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Solution-Processed, High-Performance Nanoribbon Transistors Based on Dithioperylene
Abstract
Solution-processed, high-performance 1D single-crystalline nanoribbon transistors fabricated from dithioperylene are described. The integration of two sulfur atoms into the perylene skeleton induces a compressed highly ordered packing mode directed by S···S interactions. The mobilities of up to 2.13 cm(2) V(-1) s(-1) for a dithioperylene individual nanoribbon make it particularly attractive for electronic applications.
... d Relative quantum yield is calculated with respect to Rhodamine-6G (λ ex = 530 nm) in ethanol solution as the standard and compound in CHCl 3 . e Relative quantum yield is calculated with respect to tetrakis(octyl)-1H-phenanthro [1,10,9,8]carbazole-3,4,9,10-tetracarboxylate in THF solution as the standard. f Calculated from the red edge of the absorption band. ...
... Similarly, Jiang et al. reported the crystalline nanoribbon transistors fabricated from bis-S-annulated perylene, which exhibited enhanced charge carrier mobility of 2.13 cm 2 V À 1 s À 1 . [9] The integration of two sulfur atoms in the perylene molecular structure led to a highly ordered packing, once again due to strong S···S interactions. Mullen's group introduced a bis-S-annulated perylene tetraester with sulfur annulation at both bay positions; [10] however, the photophysical and liquid crystalline behavior of these compounds was not reported. ...
This study presents a comparative analysis of S‐annulated perylene tetraester (PTE‐S) and its sulfone (PTE‐SO2) analogue. This sulfone modification reduced melting point and stabilized a room temperature columnar rectangular (Colr) phase in contrast to its parent PTE‐S which showed a crystalline behaviour at room temperature. This molecular design also leads to red‐shifted absorbance and emission in comparison to PTE‐S, along with a tuning of photoluminescence from sky blue to green, achieving an impressive quantum yield of 85 %. OLED devices fabricated using PTE‐SO2 as emitter material at concentrations of 0.2, 0.5, and 1 wt.% in CBP as host material. A maximum external quantum efficiency (EQE) of 2.9 % was observed with the 0.5 wt.% PTE‐SO2 in CBP with CIE coordinates of (0.45, 0.35), accompanied by an orange luminance of 848 cd/m². Notably, a device with a 0.5 wt% doping concentration of PTE‐S demonstrates an EQE of 3.5 %, and cyan luminance of 2,598 cd/m².
... [5][6][7] In addition, sulfur and selenium incorporated organic semiconductors are gaining importance due to the additional intermolecular S···S and Se···Se interactions. [8][9][10][11][12][13][14][15][16] Considering the presence of oxygen (O) atoms from the carbonyls of imide units in PBIs, Further, there is a possibility of S⋯O and Se⋯O interactions which involve sulfur and selenium σ-holes. [17,18] This compliments the molecular selfassembly and also could play a major role in enhancing 1D charge transport. ...
... However, the XRD pattern obtained at 28°C exhibited this core-core separation peak corresponding to the packing of discs with in the column with an intracolumnar distance of 3.31 Å (Figure 3b). The low angle and mid angle region were composed of many peaks with d-spacings of 25.20 Å, 12.99 Å, 11.26 Å, 10.20 Å and 6.85 Å which can be assigned to Miller indices (01), (12), (22), (À 12), (42) of an oblique lattice with lattice parameters a = 28.1 Å, b = 26.4 Å and γ = 72.7° ...
Highly electron‐deficient heteroatom (N, S, Se) bay‐annulated PBIs exhibiting ordered columnar phase over a wide mesomorphic range including ambient temperature are reported in this manuscript. These compounds with six peripheral n‐decyloxy chains exhibited absorption spectra with high molar extinction coefficients, electron‐deficient nature and self‐assembling behaviour. A detailed comparison with the PBIs bearing six peripheral n‐decyl chains was also carried out to get the valuable insights on the structure‐property relations in this important class of organic semiconductors. Both of the PBI series were tested for their charge carrier mobility by space charge limited current method and found that they exhibit ambipolar conductivity. This is in contrary to the vast body of literature, where most of the PBI based semiconductors exhibit electron transport behaviour. In general, PBIs derived from tri‐n‐alkyl anilines exhibit higher mobility values than the PBIs derived from tri‐n‐alkoxy anilines. Especially, the ambipolar S‐annulated PBI derived from tri‐n‐alkyl aniline exhibited highest hole (8.39×10⁻³ cm²/V.s) and electron (1.5×10⁻² cm²/V.s) mobility values and promising for the application in organic electronics.
... [10][11][12][13][14][15][16] Furthermore, the S-annulated perylene derivatives are recognized for their attractive SÁ Á ÁS interactions, which promote the one-dimensional stacking or orderly arrangement of molecules, facilitating the close alignment of the p-orbitals and consequently, enhancing charge carrier mobility. [15][16][17][18][19] Beyond their remarkable electron-transporting capabilities, these derivatives exhibit impressive luminescent properties. This combination of impressive luminescent properties along with the remarkable electron-transporting capabilities of these derivatives positions them as frontrunners for propelling the domain of organic light-emitting diodes (OLEDs). ...
Highly fluorescent ambient mesogenic bay S-annulated swallow tail appended perylene bisimide with enhanced electroluminescence breaking the maximum EQE for fluorescent OLEDs in a host–guest configuration with CBP.
... The carbonyl group in FCO-and TCO-owns n-* transition, which can strengthen spin-orbit coupling (SOC) and thus facilitate reversible intersystem crossing (RISC) to promote delayed fluorescence. And theextended planar skeletons with embedded heteroatoms are prone to form abundant intermolecular interactions [11] (e.g., -interactions, hydrogen bonds) amongst FCO-and TCO-, which are conducive to sparking ordered arrangements and ultimately accelerating charge transport of FCO-1 and TCO-1. [12] The neat films of FCO-1 and TCO-1 exhibit strong delayed fluorescence, large horizontal dipole ratios (Θ // s), and ultrafast bipolar charge transport under ambient atmosphere with μ e and μ h reaching 0.135 and 0.034 cm 2 V −1 s −1 , respectively, at an electric field www.advancedsciencenews.com www.afm-journal.de of 1.0 × 10 6 V cm −1 . ...
Achieving strong solid‐state photoluminescence and fast charge transport simultaneously for organic molecules is of significant importance but challenging because of the trade‐off between these properties. Herein, two tailored blue luminescent molecules constructed with ring‐fused carbonyl‐containing electron acceptors and spiro‐acridine electron donors are developed. Owing to ordered long‐range molecular alignment with proper interaction energies, their neat films exhibit ultrafast bipolar charge transport and strong delayed fluorescence with high quantum yields and short lifetimes. In doped organic light‐emitting diodes (OLEDs), both molecules display eminent electroluminescence performances with excellent external quantum efficiencies (EQEs) of 40.6%. They also exhibit brilliant blue lights with record‐beating EQEs of 30.2% in non‐doped thin‐layer OLEDs, and more importantly, high‐performance simplified non‐doped thick‐layer OLEDs are achieved, rendering lowered driving voltages, and the best EQEs of 23.0% with tiny efficiency roll‐offs. In addition, using them as sensitizers, remarkable EQEs of 40.1% and 23.2% with ultrasmall efficiency roll‐offs are realized in blue hyperfluorescence thin‐layer and thick‐layer OLEDs, respectively. The operational lifetimes are obviously elongated matter in non‐doped thick‐layer devices or hyperfluorescence thick‐layer devices. This work provides promising candidates for efficient simplified thick‐layer OLEDs and opens a new avenue toward organic molecules with strong delayed fluorescence and fast charge transport simultaneously.
... However, 1,2-dichalcogenin cycles stabilized in highly conjugated scaffolds are not easily converted by light or thermal activation, as mentioned above, and their reactivity in the absence of external reagent (i.e., their photo-and thermal reactivity) has been far less explored than for heteropines. Nowadays, the most common protocol to trigger extrusion from 1,2-dichalcogenins and generate S-and Se-doped π-CPCs still relies on copper (as nanopowder) at high temperature under neat conditions [73][74][75][76][77]. ...
The “ precursor approach ” has proved particularly valuable for the preparation of insoluble and unstable π-conjugated polycyclic compounds (π-CPCs), which cannot be synthesized via in-solution organic chemistry, for their improved processing, as well as for their electronic investigation both at the material and single-molecule scales. This method relies on the synthesis and processing of soluble and stable direct precursors of the target π-CPCs, followed by their final conversion in situ, triggered by thermal activation, photoirradiation or redox control. Beside well-established reactions involving the elimination of carbon-based small molecules, i.e., retro-Diels–Alder and decarbonylation processes, the late-stage extrusion of chalcogen fragments has emerged as a highly promising synthetic tool to access a wider variety of π-conjugated polycyclic structures and thus to expand the potentialities of the “ precursor approach ” for further improvements of molecular materials’ performances. This review gives an overview of synthetic strategies towards π-CPCs involving the ultimate elimination of chalcogen fragments upon thermal activation, photoirradiation and electron exchange.
... Crystalline organic semiconductor NWs have demonstrated promising field-effect transistor behavior. [40][41][42] The one-dimensional character of organic NWs also offers a high surface-to-volume ratio, a property that may be exploited in photovoltaic, 43,44 optoelectronic, 45 and sensor [46][47][48] applications, as well as the potential for NW alignment, a characteristic that opens opportunities in flexible electronics 49,50 and nanoelectronics. [51][52][53] Herein, an organic NW e-synapse based on the squaraine molecule 2,4-bis[(4-diethylamino)-2-hydroxyphenyl]squaraine, SQ, is reported (see Scheme 1). ...
Nanowires (NWs) composed of 2,4-bis[(4-diethylamino)-2-hydroxyphenyl] squaraine were prepared by evaporation-induced self-assembly (EISA). NWs were ∼560 nm wide (aspect ratios: 10–90). X-ray diffraction analysis indicated polymorphism (monoclinic/triclinic). Optical data reported the triclinic phase with energetic disorder. Given the favorable alignment of the Au work function and squaraine HOMO energy, symmetric, unipolar metal–insulator–metal devices were formed by the EISA of NW meshes on inter-digitated Au electrodes. Room temperature DC I–V characteristics displayed hysteretic I–V loops, indicating memristive behavior. At low bias, data indicated Ohmic transport with carrier extraction facilitated by thermionic emission. At high biases, devices exhibited space-charge-limited conduction in the presence of shallow traps. At 77 K, data indicated Ohmic transport at low bias with carrier extraction by thermionic emission while, at high biases, trap-limited space-charge-limited conduction in the presence of traps distributed in energy, with carrier extraction by Fowler–Nordheim tunneling, was observed. The I–V hysteresis was eliminated at 77 K and attenuated by fast scan rates at room temperature, suggesting that carrier trapping/de-trapping underpinned the hysteresis. In impedance measurements, the device response fitted a Randles equivalent circuit indicating purely electronic conduction. By applying voltage waveforms, I–V hysteresis and analog resistive switching (memristive) functionality were observed. Device conductance could be increased sweep by sweep, giving conductance tuning through distinct states, with wait time- or voltage-erase options, consistent with trap filling/emptying effects. Repeated erase–write–read of multiple distinct states over many voltage cycles during continuous use in air was demonstrated. Finally, synaptic functions, e.g., pulse-dependent plasticity, and short- to long-term memory transition, were successfully emulated.
... Nevertheless, of all the fused heteroaromatic compounds explored in the literature, thiophene-fused materials are the most frequently and extensively researched [26] because of their chemical stability, capacity for forming particular intermolecular interactions, and highly electron-donating nature [27][28][29][30][31][32][33]. One of the simplest thiophene-fused and selenophene-fused compounds that may be classified as structural isomers based on the location of the fused rings are benzodithiophenes (BDTs) and benzodiselenophenes (BDSes). ...
This study's primary objective is to give a thorough examination of the comparative charge transport and optoelectronic characteristics of all conceivable isomers of benzodithiophene (BDT) and benzodiselenophene (BDSe). Density Functional Theory (DFT) simulations have been performed on all the possible isomers of benzodithiophene (BDT) and benzodiselenophene (BDSe) and results are compared with corresponding experimental known isomers. The absorption energies and HOMO–LUMO energy levels were predicted by Time-Dependent Density Functional Theory (TD–DFT). Electron and hole Reorganization Energies (RE), Hole Extraction Potential (HEP) and Electron Extraction Potential (EEP), Ionization Potentials (IP) and Electron Affinities (EA) of all the isomers are reported. The UV–visible absorption of BDT and BDSe isomers are between 250–417 nm and 290–445 nm respectively. Comparatively, the simulated hole and electron reorganization energy of all the BDT and BDSe isomers have low values and hence expected applications in the field of Organic Optoelectronic Devices.
... Thiophene fused with aromatic rings is the most often and widely studied heteroaromatic compounds described in the literature [17], depending on their chemical stability, extremely electron donor capacity and capability to form exact intermolecular interactions [19][20][21][22]. ...
The primary goal of this work is to provide a comprehensive analysis of the charge transport and optoelectronic characteristics of all the isomers of benzodifuran (BDF) for organic electronic devices in order to suggest qual- ified materials/candidates for organic photovoltaic devices. Density functional theory (DFT) calculations were performed for all possible isomers of BDF and results are compared with corresponding experimental known isomers. Time Dependent-Density Functional Theory (TD-DFT) is used for the calculation of the absorption and HOMO-LUMO energy levels. To characterize the electronic charge transport state in these isomers, the ionization potentials (IP), reorganization energies (hole and electron), and electron affinities (EA) of all the isomers are investigated. Comparatively, all the BDF isomers are having low electron and hole reorganization energies and hence they can be used in the organic electronic material fabrication.
... In particular, sulfur and selenium incorporation in organic semiconductors is a theme of intense research due to the additional intermolecular SÁ Á ÁS and SeÁ Á ÁSe interactions that promote molecular self-assembly and 1D conductivity. [38][39][40][41][42][43][44][45][46] Especially, chalcogen atoms like S and Se, when forming covalent bonds, their bonding orbitals have a deficiency of electronic charge in their outer (noninvolved) lobe, which is known as a s-hole. If the atom is sufficiently polarizable, the s-hole may have a positive electrostatic potential that can interact with a nucleophilic site in its proximity to form a noncovalent bond or it can form the same with the regions of negative electrostatic potential on the same atoms. ...
A series of electron deficient perylene bisimides (PBIs) bearing 3,4,5-tridecylphenyl substituents on the imide N-atoms and bay-annulated with the hetero atoms like N, S, Se in the bay positions of...
... In the past decades, our group has been However, experimentally bringing these imagined molecules into existence by chemical synthesis represents a gigantic challenge. No precedent has been known for bridging all six bay regions of p-HBCs to form decorated pentagonal rings, albeit methodologies for bridging the bays of triphenylene [27,28] and perylene [24,29,30] Supplementary Fig. 55). 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 6 or Cl· · · π interactions with the formation of chlo- 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 at the M062x/6-31g(d) level of theory (Fig. 7) revealed that the inversion would proceed via a planar transition state like corannulene [55][56][57][58] and sumanene [59,60] Fig. 41). ...
Synthesis of buckybowls, especially, the large sized ones, have remained a huge challenge yet due to the inherent high strain induced by curvature. Herein, we report two novel bowl-shaped polycyclic aromatics with three chalcogen (sulfur or selenium) atoms and three methylene groups embedded at the bay regions of hexa-peri-hexabenzocoronene and an expeditious three-step synthetic strategy for these superbowls, including an aldol cyclotrimerization, a Scholl reaction, and a Stille reaction. The superbowls of this type feature a nanosized, compact, and C3vsymmetric architecture, composing of 19 fused rings, 48 constituent atoms. NMR spectroscopic and X-ray crystallographic studies confirmed their bowl-shaped geometries. The crystal structures revealed that they encompass 36 pyramidalized trigonal carbon atoms and have the bowl depths of 2.29 ˚A and 2.16 ˚A and diameters of 11.06 ˚A and 11.35 ˚A for the sulfur and selenium isologs. The curvature mainly distribute at the carbon atoms of the coronene frame and edge-to-convex packing predominates due to intermolecular C–H· · · π and chalcogen· · · π interactions in two instances. Variable temperature 1H NMR experiments and theoretical calculations demonstrated the bowls have considerably high inversion barriers. The optical and electrochemical properties were elucidated by UV/vis and fluorescence spectroscopy and cyclic voltammetry. Moreover, the aromaticity distribution and electrostatic potential characteristics as well as perpendicularly aligned convex-to-concave dipolemoments were investigated by density functional theory calculations.
... Hetero-π-conjugated molecules are attractive substructures for assembling superstructures of heteroatom-annulated molecular carbons [1][2][3][4]. Despite the comprehensive researches on the N- [5][6][7][8][9], S(O)- [10][11][12][13], B(BN)- [14][15][16][17], and Si-based conjugated scaffolds [18][19][20][21], P-heteroannulation within the sp 2 -carbon backbones could offer characteristic structure with pyramidal geometries, as well as unique nature due to the valence state of the P atom and the presence of a lone pair of electrons [22][23][24]. To this end, recent investigations have unravelled the prospects of organophosphorous materials in organic/bioelectronics, such as organic light emitting diodes (OLEDs) [25], organic photovoltaics (OPVs) [26], liquid crystals [27], electro/photochromics [28,29], and bioimaging probes [30]. ...
The development of hetero-π-conjugated molecules is of significance for constructing diverse assembling superstructures based on heteroatom-related bonded or nonbonded interactions. Herein, we developed one-pot P-heteroannulation via palladium-catalyzed dual P—C bonds formation and subsequent sulfidation to construct two isomeric diphosphaperylenediimides (cis-5 and trans-5). The unique out-of-plane anisotropic π-framework induced a cumulative anisotropy with a dipole moment of up to 8.82 D for cis-5, leading to distinct supramolecular packing arrangements. Optical and electrochemical characterizations demonstrated that they showed the largest redshifts extending to 574 nm and rather low-lying LUMO levels of −4.41 eV. Furthermore, the introduced P=S moieties endowed these diphosphaperylenediimides with prominent coordination ability towards Ag+, thus the first example of perylene diimide (PDI) core-involved metal-organic coordination polymers (MOCPs) with tunable dimensionality varied from 1D, 2D, to 3D were tactfully achieved. In view of easy accessibility and 2D layered porous structure, thus 2D (trans-5)·(AgOTf) based MOCP showed high crystallinity and good CO2 adsorption capacity with surface area of 112 m2/g. The result opens a span-new avenue for exploring rylene imide-based MOCPs and related properties by integrating P functionality.
... [83][84][85] Furthermore, the sulfur atoms can also improve inter-chain coupling and lower the first ionization potential. [86][87][88] Especially, the molecule containing the thiophene rings can pack in a planar structure, which is also beneficial to achieve high mobility. As a result, hydrocarbons with thiophene groups attracted great attention to developing high mobility organic semiconductors. ...
Organic semiconductors have been receiving intensive attention due to the specific advantages of low‐temperature processing ability, low‐fabrication cost, flexibility, and so forth. The charge carrier mobility of higher than 10 cm² V⁻¹ s⁻¹ for organic semiconductors is of great importance to be studied since it presents a future promising research direction toward commercial microelectronic applications. With the significant progress of the discovery of novel organic molecules and the further improvements of device fabrication technology, some organic molecules can break the limit of our knowledge and show very high mobilities. In this review, organic polymers and small molecules with mobilities above 10 cm² V⁻¹ s⁻¹ are first introduced to provide the readers with a general understanding of the features and characteristics of high‐performance organic semiconductors. Then, some important parameters, including the molecular structures, the device configurations, and the performance, are discussed in detail. Finally, the clues to obtain high mobility are summarized, and the perspective toward the future possible research directions are also provided.
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... For example, 3 based OTFTs exhibited mobilities of 0.13 cm 2 V −1 s −1 [27], whereas 5 based OTFTs exhibited mobilities of 2.1 cm 2 V −1 s −1 (Fig. 3) [29]. Mobility as high as 0.8 cm 2 V −1 s −1 are recorded for single crystal transistors 4. Additionally, perylene analogue, 6 illustrated a highly compressed and ordered packing mode, and the FET mediated on individual nano-ribbon displayed a high mobility up to 2.13 cm 2 V −1 s −1 [28]. These excellent results give sulfur bearing perylene derivatives a great value and attraction for electronic applications (Table 2). ...
Organic electronics has been a popular field for the last two decades, due to its potential to commercialize cheap-price and large-area flexible electronics. The devices based on organic compounds heavily rely on organic semiconductors (OSs). Primary challenge for materials chemist is the new OSs construction that has ameliorated attainment in organic thin film transistors (OTFTs) and organic field effect transistors (OFETs). The construction of air-stable (stable in air) n-channel OSs (electron-conducting materials) is particularly needed with capability comparable to that of p-channel materials (hole-conducting materials). In the last 10 years, there have been significant advancements in thiophene-based OSs. Thiophene-mediated molecules have a prominent role in the advancement of OSs. The main significance in thiophene-based molecules is their cheap-price (in comparison to silicon), processability at low temperature, structural flexibility, ability to be applied on flexible substrates, and high charge transport characteristics. In this paper, we review the progress in the performance of thiophene-based OSs that has been reported in the last 18 years, with a major emphasis on the last 10 years. This approach provides a crisp introduction to organic devices and catalogs progress toward the fabrication of thiophene containing p, n and ambipolar channel OSs, and discusses their characteristics. Finally, review discusses current challenges and future research directions for thiophene based OSs. This review would be beneficial for further developments in the technological performance. Moreover, this review will serve to accelerate knowledge and lays the foundation for improved applications. Hopefully, this struggle pushes the reader’s mind to consider new perspectives, think differently and forge new connections.
... [11][12][13][14] Among 1D microstructures, organic single-crystal microwires ("SCMWs"), being free of grain boundaries and molecular disorder, facilitate directional charge transport and exciton diffusion. 15,16 High-performance OFETs based on SCMWs have been reported for various small conjugated molecules. For instance, OFETs based on fullerene C 60 needle-like single crystals exhibit electron mobilities exceeding 10 cm 2 V −1 s −1 , 17 which is one of the highest among OFETs based on solution-grown organic single crystals. ...
There are only a few reported methods by which the size and morphology of organic single crystals for high-performance organic field-effect transistors (OFETs) or other devices can be controlled. Here, a facile solution-processed antisolvent vapor diffusion method was employed to grow millimeter-length C60 single crystal microwires directly in the solution. The size of the microwires can be controllably varied via the C60 concentration and/or the choice of antisolvent. OFETs fabricated from the as-produced microwires exhibit mobilities as high as 2.30 cm2 V-1 s-1. A clear relationship between crystal preparation condition and device performance is revealed whereby the lower the evaporation rate of antisolvent and/or the higher the C60 concentration, the higher the devices performance. Photodetectors based on our microwires give a responsivity that is an order of magnitude higher than those grown by drop-casting methods. This study provided a facile method for the crystal engineering of size-tunable millimeter-length C60 single crystals, and revealed the important influences of antisolvent to the C60 crystal size and the performance of devices based on them. We believe that our processing approach can be further exploited for a broad range of other organic semiconductors to achieve desirable single crystal size and morphology and thus desirable OFETs and photodetector performance.
The continuous innovation of captivating new organic semiconducting materials remains pivotal in the development of high‐performance organic electronic devices. Herein, a molecular engineering by combining sila‐annulation with the vertical extension of rylene diimides (RDIs) toward high‐mobility organic semiconductors is presented. The unilateral and bilateral sila‐annulated quaterrylene diimides (Si‐QDI and 2Si‐QDI) are designed and synthesized. In particular, the symmetrical bilateral 2Si‐QDI exhibits a compact, 1D slipped π–π stacking arrangement through the synergistic combination of a sizable π‐conjugated core and intercalating alkyl chains. Combining the appreciable elevated HOMO levels and reduced energy gaps, the single‐crystalline organic field‐effect transistors (SC‐OFETs) based on 2Si‐QDI demonstrate exceptional ambipolar transport characteristics with an impressive hole mobility of 3.0 cm² V⁻¹ s⁻¹ and an electron mobility of 0.03 cm² V⁻¹ s⁻¹, representing the best ampibolar SC‐OFETs based on RDIs. Detailed theoretical calculations rationalize that the larger transfer integral along the π–π stacking direction is responsible for the achievement of the superior charge transport. This study showcases the remarkable potential of sila‐annulation in optimizing carrier transport performances of polycyclic aromatic hydrocarbons (PAHs).
Oligothiophenes and thienoacenes are essential components of organic semiconductors and usually form the herringbone structure with a dihedral angle of θ = 50 - 60 o . However, when more than three...
The increasing demand for polycyclic aromatic hydrocarbons (PAHs) as an advanced material led to significant interest among synthetic and material science community. PAHs being highly conjugated are found to have good absorption and emission properties. Heteropolycyclic aromatic hydrocarbons (hetero‐PAHs) are those with one or more heteroatoms in the carbon framework, and they have multifold applications in optoelectronics. Synthesis of such molecules via directed CH functionalization has reduced the time, energy, and more importantly multiple steps in comparison with their classical synthesis. In this article, the synthesis of these valuable doped‐PAHs/hetero‐PAHs through directed CH functionalization has been documented.
Catalysis has always been part of the development of mankind; from the fermentation of alcoholic drinks, through the development of fertilisers in the agricultural revolution and production of bulk chemicals in the 20th Century. Today, society demands improved production routes with greater product output and energy efficiency; the ultimate goal to achieving this would be having all catalytic reactions in concert, effectively functioning like a biological cell.
Metal organic frameworks (MOFs) are a relatively new type of hybrid material. Their crystalline porous structure, built up from organic and inorganic building blocks, presents a vast array of composition, porosity and functionality offering enormous potential in catalytic systems.
This book examines the latest research and discovery in the use of MOFs in catalysis, highlighting the extent to which these materials have been embraced by the community. Beyond presenting a digest of recent research by major players in the field, the book presents the strategies behind recent developments, providing a lasting reference for seasoned researchers and newcomers to the field.
Weak intermolecular interactions, such as π-π interactions, hydrogen bonds, halogen bonds and charge transfer interactions, are important to tuning the physical properties of organic charge transfer cocrystals. However, it is...
A catalyst-free method for the synthesis of dibenzothiophenes has been developed. The nucleophilic intramolecular cyclization of methylthiolated diazonium salts enables the direct synthesis of dibenzothiophenes under mild reaction conditions. The addition of TEMPO is beneficial for improving the reaction yield by suppressing the formation of by-products, which can be formed via a radical-mediated process. This simple method provides an alternative for the synthesis of dibenzothiophenes, which are frequently found in valuable compounds.
Rare studies of cocrystal engineering have focused on improving carrier mobility of organic semiconductors mainly because of the generation of ambipolarity, the alteration of the charge carrier polarity or the reduction of electronic couplings. Herein, we utilize indolo[2,3‐a]carbazole (IC) as the model compound and 2,6‐diphenylanthraquinone (DPAO) and 9‐fluorenone (FO) as the coformers to construct IC2‐DPAO and IC‐FO cocrystals with 2:1 or 1:1 ratios respectively through hydrogen bonds and donor‐acceptor interactions. Very interestingly, the more appropriate packing structure, possessing not only enhanced electronic couplings but also increased intermolecular distances, is achieved in IC2‐DPAO, which shows an improved carrier mobility of 0.11 cm 2 V −1 s −1 by four orders of magnitude relative to IC crystal. These results suggest that non‐equal ratio cocrystal engineering opens up the possibility to the development of organic semiconductors with enhanced charge transport behaviors.
Rare studies of cocrystal engineering have focused on improving carrier mobility of organic semiconductors mainly because of the generation of ambipolarity, the alteration of the charge carrier polarity or the reduction of electronic couplings. Herein, we utilize indolo[2,3‐a]carbazole (IC) as the model compound and 2,6‐diphenylanthraquinone (DPAO) and 9‐fluorenone (FO) as the coformers to construct IC2‐DPAO and IC‐FO cocrystals with 2 : 1 or 1 : 1 ratios, respectively, through hydrogen bonds and donor–acceptor interactions. Interestingly, the more appropriate packing structure, possessing not only enhanced electronic couplings but also increased intermolecular distances, is achieved in IC2‐DPAO, which shows an improved carrier mobility of 0.11 cm² V⁻¹ s⁻¹ by four orders of magnitude relative to the IC crystal. These results suggest that non‐equal ratio cocrystal engineering opens up the possibility to develop organic semiconductors with enhanced charge transport behaviors.
Chronic non-communicable diseases are the major cause of death globally. Whole grains are recommended in dietary guidelines worldwide due to increasing evidence that their consumption can improve health beyond just providing energy and nutrients. Epidemiological studies have suggested that the incorporation of whole grains, as part of a healthy diet, plays a key role in reducing one’s risk for cardiovascular diseases (CVDs), obesity, type 2 diabetes (T2D) and cancer. Phenolic acids and dietary fibre are important components found in whole grains that are largely responsible for these health advantages. Both phenolic acids and dietary fibre, which are predominantly present in the bran layer, are abundant in whole-grain cereals and pseudo-cereals. Several studies indicate that whole grain dietary fibre and phenolic acids are linked to health regulation. The main focus of this study is two-fold. First, we provide an overview of phenolic acids and dietary fibres found in whole grains (wheat, barley, oats, rice and buckwheat). Second, we review existing literature on the linkages between the consumption of whole grains and the development of the following chronic non-communicable diseases: CVDs, obesity, T2D and cancer. Altogether, scientific evidence that the intake of whole grains reduces the risk of certain chronic non-communicable disease is encouraging but not convincing. Based on previous studies, the current review encourages further research to cover the gap between the emerging science of whole grains and human health.
Herein, we present silver nanoparticle anchored on copper oxide and copper hydroxide (Ag@CuO@Cu(OH)2) by green synthetic approach. Interestingly, as‐obtained Ag@CuO@Cu(OH)2 not only enhances the peroxidase‐like activity but also eliminates oxidase‐like activity. The peroxidase‐like activity was enhanced mainly due to the abundance of Ag⁺ and Cu²⁺ vacant states, which populate reactive oxygen species (ROS). This prolonged peroxidase‐like activity of Ag@CuO@Cu(OH)2 was successfully recognized H2O2 and also have long stability and repeatability. The proposed strategy, finding nanozymes with single activity will open a new opportunity to enhance the performance of colorimetric sensors.
For years, concepts and models relevant to the fields of molecular electronics and organic electronics have been invented in parallel, slowing down progress in the field. This book illustrates how synthetic chemists, materials scientists, physicists, and device engineers can work together to reach their desired, shared goals, and provides the knowledge and intellectual basis for this venture.
Supramolecular Materials for Opto-Electronics covers the basic principles of building supramolecular organic systems that fulfil the requirements of the targeted opto-electronic function; specific material properties based on the fundamental synthesis and assembly processes; and provides an overview of the current uses of supramolecular materials in opto-electronic devices. To conclude, a “what’s next” section provides an outlook on the future of the field, outlining the ways overarching work between research disciplines can be utilised.
Postgraduate researchers and academics will appreciate the fundamental insight into concepts and practices of supramolecular systems for opto-electronic device integration.
Nanoconfinement of organic semiconductors in nanoporous templates is promising for manipulating polymorphism and molecular orientation while forming nanowires with controlled dimensions. To harness the potential advantages of templated organic semiconductor nanowires, there is a need to understand the factors that influence final nanowire structure. Little is known, however, about the extent to which nanowire morphology and internal structure are impacted by nanowire release from the boundary conditions imposed by the template. To address this knowledge gap, we assessed the morphological, crystallographic, and photophysical changes that occur in three common organic semiconductors in response to nanoporous template removal [(Bis(triisopropylsilylethynyl)pentacene (TIPS-Pn), (7,7′-[4,4-Bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]- dithiophene-2,6-diyl]bis[6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5 yl)benzo[c][1,2,5]thiadiazole] (p-DTS(FBTTh2)2), and poly(3-hexylthiophene) (P3HT)]. Although the nanowires comprising planar small molecules maintained their cylindrical shape following template removal, the investigated polymer, P3HT, exhibited extensive nanowire fusing for pore sizes of 55 nm and below, leading to a networked structure. All three systems presented preferred crystallite orientations that persisted in the freed nanowires. Nanowires generally exhibited an increasingly J-like aggregation character following template removal. Collectively, these results reveal that
subtle molecular rearrangement takes place in the small molecule systems, while significant structural rearrangement can occur in polymer systems in response to template removal.
A Rh-catalyzed pot and step economic synthesis of aza-polycyclic aromatic hydrocarbons (N-PAHs) from readily available aryl ketones and alkynes has been disclosed. Additionally, a novel synthetic application of the well-known aminating reagent hydroxylamine-O-sulfonic acid (HOSA) has been explored as an in situ redox-neutral directing group for the formation of N-PAHs via isoquinoline. Multiple bond formation in a single operation through a cascade of triple C−H bond activations is the beauty of this protocol. The challenging annulations of two different alkynes in a regioselective fashion have been demonstrated effectively. Mechanistic studies reveal that 3,4-diphenyl-1-methylisoquinoline is an active intermediate for this one-pot transformation.
Two structural isomers of naphthalene diimide (NDI) chromophores NDI‐3 and NDI‐4, which are NDI imide position functionalised with four L‐/D‐alanine subunits. Density functional theory calculations revel that HOMO molecular orbital is localized on N‐phenyl substituent and LUMO on NDI core. Further, the UV‐vis, fluorescence measurements show that both the derivatives i. e. NDI‐3 and NDI‐4 exhibit changes in optical and photophysical properties with the addition of non‐polar i. e. methylcyclohexane in chloroform as well as water in tetrahydrofuran. From these results, it is clear that the structural isomers NDI‐3 and NDI‐4 shows a significant solvatochromic effect, which ascribed to the aggregation effect via π‐π stacking of NDI core along with hydrogen‐bonding between alanine side chains. Scanning electron microscopy (SEM) and polarized optical microscopy images clearly demonstrate formation of flower like morphology in THF:H2O and fiber nanostructure in CHCl3:MCH for both NDI‐3 and NDI‐4. Interestingly, only NDI‐4 in CHCl3:MCH (4 : 6, v/v) solvent mixture produces rose‐like flower microstructures.
To reveal the influence of synergistic effect of non-covalent forces on the FET performance, two high symmetrical “H”-shaped heteroarene derivatives anthra[2,1-b:3,4-b':6,5-b'':7,8-b''']tetra(benzothiophene) (ATBT) and anthra[2,1-b:3,4-b':6,5-b'':7,8-b''']tetra(benzofuran) (ATBF) as the novel two-dimensional (2D) organic semiconductor materials were synthesized. The thermal, optical and electrochemical properties of ATBT and ATBF were investigated and high stability was confirmed. Single-crystalline XRD of ATBT confirmed the close π-π stacking due to the “wider” π-conjugation frame-work and the four S atoms site on the both sides of each molecule could produce eight S…S contacts with neighbour molecules. Mobility up to 15.6 cm2V-1s-1 could be achieved for the single-crystalline field effect transistor which fabricated by the ‘‘two-dimensional organic-ribbon mask’’ technique based on the individual ATBT microribbon. The strong anisotropy along different crystal axes is consistent with the molecular arrangement which evidenced by XRD, TEM and corresponding selected-area electron diffraction pattern. Moreover, the analogue ATBF shows lower FET performance due to lacking of S…S contacts in comparison to that of ATBT, which reflects that the synergistic effect of non-covalent forces has important influence on the molecular aggregation and electrical properties.
An application of dechalcogenization of aryl dichalcogenides via copper catalysis to synthesize aryl chalcogenides is dis-closed. This approach is highlighted by the practical conditions, broad substrates scope and good functional group tolerance with several sensitive groups such as aldehyde, ketone, ester, amide, cyanide, alkene, nitro and methylsulfonyl. Further-more, the robustness of this methodology is depicted by the late-stage modification of estrone and synthesis of vortioxetine. Remarkably, synthesis of more challenging organic materials with large ring tension under milder conditions and synthesis of some halogen contained diaryl sulfides which could not be synthesized using metal-catalyzed coupling reactions of aryl halo-gen are successfully accomplished with this protocol.
The density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods have been used to investigate the persulfurated coronene (PSC) and its chalcogenide analogues (POC and PSeC), derived from the substitution of sulfur, oxygen, and selenium for all hydrogen atoms in coronene, respectively. The presence of peripheral S-S in PSC results in a σ-type lowest unoccupied molecular orbital (LUMO) and the dark low-lying states (S1 ∼ S15). The peripheral S-S bond is responsible for its electron capture, which maintains a planar configuration of the singly and doubly negative-charged PSC. POC is predicted to have the most stable saddle-shaped structure with the C=O group, and its bowl-shaped isomer with the O-O moiety is less stable by 279.2 kcal/mol energetically. PSeC has similar electronic and structural features with PSC, but its dimer is predicted to have much better hole mobility, compared to PSC. The present results indicate that the chalcogenide substitution at the periphery of the polycyclic aromatic hydrocarbons may remarkably change their electronic and spectroscopic properties as well as the carrier transport behavior of their molecular materials.
Strom und Schwefel: Tetrathiotetracen(TTT)- und Hexathiapentacen(HPT)-Einkristalle wurden mit einer zonenschmelzenden chemischen Gasphasentransport-Methode synthetisiert. Als organische Batterieelektrode zeigt HTP eine überragende Leistung, was am unterschiedlichen S-S-Bindungsszenario im Vergleich zu TTT liegt. Die Anzahl benachbarter Schwefelatome beeinflusst den Charakter der S-S-Bindungen und ist wichtig für die Entwicklung neuer organischer Batteriematerialien.
Abstract
The molecular design of organic battery electrodes is a big challenge. Here, we synthesize two metal-free organosulfur acenes and shed insight into battery properties using first-principles calculations. A new zone-melting chemical-vapor-transport (ZM-CVT) apparatus was fabricated to provide a simple, solvent-free, and continuous synthetic protocol, and produce single crystals of tetrathiotetracene (TTT) and hexathiapentacene (HTP) at a large scale. Single crystals of HTP showed better Li-ion battery performance and higher cycling stability than those of TTT. A two-step, three-electron lithiation mechanism instead of the commonly depicted two-electron mechanism is proposed for the HTP Li-ion battery. The superior performance of HTP is linked to unique trisulfide bonding scenarios, which are also responsible for the formation of empty channels along the stacking direction. In-depth theoretical analysis suggests that organosulfur acenes are potential prototypes for organic battery materials with tunable properties, and that the tuning of sulfur bonds is critical in designing these new materials.
The molecular design of organic battery electrodes is a big challenge. Here, we synthesize two metal‐free organosulfur acenes and shed insight into battery properties using first‐principles calculations. A new zone‐melting chemical‐vapor‐transport (ZM‐CVT) apparatus was fabricated to provide a simple, solvent‐free, and continuous synthetic protocol, and produce single crystals of tetrathiotetracene (TTT) and hexathiapentacene (HTP) at a large scale. Single crystals of HTP showed better Li‐ion battery performance and higher cycling stability than those of TTT. A two‐step, three‐electron lithiation mechanism instead of the commonly depicted two‐electron mechanism is proposed for the HTP Li‐ion battery. The superior performance of HTP is linked to unique trisulfide bonding scenarios, which are also responsible for the formation of empty channels along the stacking direction. In‐depth theoretical analysis suggests that organosulfur acenes are potential prototypes for organic battery materials with tunable properties, and that the tuning of sulfur bonds is critical in designing these new materials.
Solution-phase synthesis of buckybowls remains a big challenge and there are limited reports on the fragments of C70. Herein, we report a new basic subunit of C70 with C2v symmetry, the dicyclopenta[4,3,2,1-ghi:4',3',2',1'-pqr]perylene (2CP-Per). Its aryl-substituted derivative 2CP-Per-Ar was synthesized and shows a bowl-shaped geometry according to X-ray crystallographic analysis. A fast bowl-to-bowl inversion process was observed above 183 K by VT NMR, with a small inversion energy barrier. 2CP-Per-Ar displays amphoteric redox behavior with a small electrochemical energy gap (1.29 eV). Different from many other aromatic buckybowls, 2CP-Per exhibits global anti-aromaticity with a strong paratropic ring current associated with the 16π-electrons rim, as revealed by NMR measurements and theoretic calculations. Its dianion is aromatic, similar to its isoelectronic structure coronene. Its dication is predicted to be aromatic, with a [6]annulene-within-[14]annulene structure.
The use of metal complex immobilized/decorated porous materials as catalysts has found various applications. As such, finding a new and mild method for synthesis of metal complex immobilized over porous material is of great interest. Immobilized porous materials for styrene oxidation were reported in this work. Immobilized porous material of Cu‐Schiff base complex @MIL‐101 were described, in which immobilized Cu‐Schiff base complex within super cage of a metal‐organic framework (MOF)‐based porous material, chromium (III) terephthalate MIL‐101. They were systematically characterized by using elemental analysis, powder X‐ray diffraction, fourier transform infrared spectroscopy, N2 absorption‐desorption, and so on, also used as catalyst for the selective oxidation of styrene to benzaldehyde. Comparatively, the immobilized heterogeneous catalyst of Cu‐Schiff base complex@MIL‐101 acted as an efficient heterostructure catalyst in the oxidation of styrene to benzaldehyde up to six cycles, and showed superior activity for styrene oxidation over MIL‐101.
L’opinion publique est consciente que l’électronique qui nous entoure présente un coût de développement et de production important en plus d’un impact environnemental non négligeable. C’est dans le but de résoudre ces inconvénients que l’électronique organique est étudiée et développée. L’électronique organique a été introduite par la découverte de polymères conducteurs, par les prix Nobel de chimie de l’année 2000, Alan J. Heeger, Alan G. MacDiarmid et Hideki Shirakawa. Depuis lors cette technologie c’est grandement développée, on note ainsi de nos jours la commercialisation des écrans OLED (Organic Light Emitting Diode) mais aussi d’autres composants organiques comme les MEMS (Micro ElectroMechanical System), des systèmes liant l’électronique et la mécanique. Ces MEMS organiques sont de plus en plus étudiés et développés dû à une plus grande flexibilité des semi-conducteurs organiques par rapport à leurs homologues inorganiques. Cependant, même si la recherche sur la mécanique des polymères et l'électronique des semi-conducteurs organiques est avancée, l'interaction électromécanique de ces semi-conducteurs n'est que peu étudiée. Néanmoins, il est nécessaire de comprendre cette interaction pour développer l'électronique flexible de demain. L'objectif de ces travaux est donc d'approfondir les connaissances sur l'interaction électromécanique au sein des semi-conducteurs organiques et de développer des outils/méthodes facilement transposables à l'étude de nouvelles molécules. Pour mieux comprendre l'interaction entre la déformation de la structure des semi-conducteurs et leur réponse électrique, ces derniers sont fabriqués sous forme de monocristaux pour étudier un arrangement moléculaire parfait, sans défauts, dans les trois dimensions de l'espace. Ainsi donc dans un premier temps, l'influence de la structure moléculaire sur la mobilité des charges a été étudiée dans le cas du rubrène. Même s'il est majoritairement avancé que la distance intermoléculaire est la raison de la variation de mobilité dans le rubrène, il s'avère que la réponse électrique dépend en réalité d'un réarrangement moléculaire et de la variation d'une multitude de paramètres intra/intermoléculaires modifiant le couplage électronique entre molécules. Dans un deuxième temps, la réponse électromécanique de transistors, à diélectrique d’air, à base de rubrène a été étudiée. Dans ces systèmes plus complexes, plusieurs paramètres sont modifiés lors de la déformation. A l'aide du facteur de jauge, il est possible de mettre en évidence que la réponse électromécanique de ces transistors dépend majoritairement de la modification mécanique et électrique du contact entre le semi-conducteur et les électrodes. La forte amélioration de la réponse électrique des transistors a permis la fabrication de capteurs de forces capables de mesurer des forces de l'ordre de 230 nN. Finalement, les méthodes développées et utilisées lors de ces travaux ont été utilisées pour amorcer la fabrication et caractérisation électrique de transistors à base de pérovskites hybrides, dans le but d'étudier l'interaction électromécanique de ces matériaux émergents.
Three pairs of regioisomers of the planar acridone derivatives (9 vs 10, 11 vs 12, and 13 vs 14), classified as the 1-cyclized compounds (9, 11, and 13) and the 3-cyclized (or 1,3'-cyclized) regioisomers (10, 12, and 14), have been synthesized, and their X-ray structures have been determined. The 1-cyclized compounds have higher yields and lower energies compared with their 3-cyclized isomers. The fluorescence spectra of the intramolecular H-bond containing compounds (9, 11, 13, and 14) consist of two bands (shorter wavelength band for the keto form and longer wavelength band for the enol form) and exhibit the feature of the excited-state intramolecular proton transfer (ESIPT). The density functional theory (DFT) theoretical investigation of the reorganization energy (λ) with respect to molecular symmetry revealed that planar rigid- C2 v-symmetric polycyclic heteroaromatic molecules (such as acridone, 1, and 13) can have low charge-transport barrier (small λ value) and keep the invariance of the molecular point group in the charge-transport process, and therefore can have high hole mobility.
Direct arylation represents an attractive alternative to the conventional cross‐coupling methods because of its step‐economic and eco‐friendly advantages. A set of simple D–A oligomeric molecules (F‐3, F‐5, and F‐7) by integrating thiophene (T) and tetrafluorobenzene (F4B) as alternating units through a direct arylation strategy is presented to obtain high‐performance charge‐transporting materials. Single‐crystal analysis revealed their herringbone packing arrangements driven by intensive C−H⋅⋅⋅π interactions. An excellent hole‐transporting efficiency based on single‐crystalline micro‐plates/ribbons was witnessed, and larger π‐conjugation and D–A constitution gave higher mobilities. Consequently, an average mobility of 1.31 cm² V⁻¹ s⁻¹ and a maximum mobility of 2.44 cm² V⁻¹ s⁻¹ for F‐7 were achieved, providing an effective way to obtain high‐performance materials by designing simple D–A oligomeric systems.
A palladium-catalyzed synthesis of dibenzothiophenes from 2-biphenylthiols is described. This highly efficient reaction employs a simple PdCl2/DMSO catalytic system, in which PdCl2 is the sole metal catalyst and DMSO functions as an oxidant and solvent. This transformation has broad substrate scope and operational simplicity and proceeds in high yield. The synthetic utility was demonstrated by the facile synthesis of helical dinapthothiophene 3 and an eminent organic semiconductor DBTDT 4. Importantly, highly strained trithiasumanene 5, a buckybowl of considerable synthetic challenge, was observed under this catalytic system.
Acenes/heteroacenes, the most widely studied small‐molecule organic semiconductors, always possess linear structures. In this work, three stable, soluble and angular π‐exteneded hepta‐thienoacenes with internal carbazole, i.e., thienobenzo‐fused carbazole (DTBCz) were synthesized via a four‐step tandem method. The tandem synthesis starting from carbazole derivatives resulted into an interesting isomeric effects. The synthetic regioselectivity was discussed in detail. Their physical properties and electron density distributions were studied by UV‐vis absorption, photoluminescence, thermogravimetric analysis (TGA), differenctial scanning calorimetry (DSC), cyclic voltammetry (CV) measurements and theoretical calculations. Their potentials as semiconducting materials were evaluated by fabricating the solution‐processed organic field‐effect transistors (OFETs). The more angular shaped isomer of DTB[32,34]Cz displayed the best performance with hole mobility up to 0.0044 cm2 V‐1 s‐1 in devices with a thickness of ca. 115 nm. Particularly, the performance of DTB[32,34]Cz‐based devices showed less dependence on the thickness of their active layer.
Protein self‐assembly processes, by which polypeptides interact and independently form multimeric structures, lead to a wide array of different endpoints. Structures formed range from highly ordered molecular crystals to amorphous aggregates. Order arises in the system from a balance between many low‐energy processes occurring due to a set of interactions between residues in a chain, between residues in different chains, and between solute and solvent. In Nature, self‐assembling protein systems have evolved over millions of years to organize into supramolecular structures, optimized for specific functions, with this propensity determined by the sequence of their constituent amino acids, of which only 20 are encoded in DNA. The structural materials that arise from biological self‐assembly can display remarkable mechanical properties, often as a result of hierarchical structure on the nano‐ and microscales, and much research has been devoted to mimicking and exploiting these properties for a variety of end uses. This work presents a review of a range of studies in which biological functions are effectively reproduced through the design of self‐assembling fibrous protein systems. The range of biomimetic structures that can be prepared by the exploitation of the tendency of proteins to self‐organize into extended fibrillar structures is explored, with a specific focus on applications in reproducing biological functionality through the design of the aggregating species and the conditions under which the self‐assembly process proceeds.
Solution-processed organic single-crystalline donor–acceptor heterojunctions
(SCHJs) composed of N,N,N′,N′-tetraphenylbenzidine (TPB) and phenyl-
C61-butyric acid methyl ester ([60]PCBM) are successfully obtained, and
fundamental studies on its charge transport properties are demonstrated,
revealing the advantages of applying SCHJs in photovoltaic devices. The SCHJs
exhibit a balanced high-mobility ambipolar charge transport with both hole and
electron mobility being more than one-order magnitude higher than its thin-film
heterojunction (TFHJ) counterparts. The difference between single-crystalline
and TFHJs in charge transport mechanisms was revealed, and it is shown that
SCHJs present a more favorable band-like charge transport properties at room
temperature. Organic photovoltaics fabricated on SCHJs present much higher
current density and a 32-times higher power conversion efficiencies than TFHJ
devices. The present work, which outlines comprehensive advantages of SCHJs
in charge transport properties, should accelerate the application of organic
single crystals for high-performance photovoltaics.
Three new heteroatom bay-annulated perylene bisimides (PBIs) have been synthesized by microwave-assisted synthesis in excellent yield. N-annulated and S-annulated perylene bisimides exhibited columnar hexagonal phase, while Se-annulated perylene bisimide exhibited low temperature columnar oblique phase in addition to the high temperature columnar hexagonal phase. The cup shaped bay-annulated PBIs pack into columns with enhanced intermolecular interactions. In comparison to PBI, these molecules exhibited lower meting and clearing temperature, with good solubility. A small red shift in the absorption was seen in the case of N-annulated PBI, while S- and Se-annulated PBIs exhibited blue-shifted absorption spectra. Bay-annulation increased the HOMO and LUMO levels of the N-annulated perylene bisimide, while a slight increase in the LUMO level and a decrease in the HOMO levels were observed in the case of S- and Se-annulated perylene bisimides, in comparison to the simple perylene bisimide. The band gaps of PBI and PBI-N were almost same, while an increase in the band gaps were observed in the case of S- and Se-annulated PBIs. The tendency to freeze in the ordered glassy columnar phase will help to overcome the charge traps due to crystallization, which are detrimental to one-dimensional charge carrier mobility. These solution processable electron deficient columnar semiconductors with good thermal stability will form an easily accessible promising class of n-type materials.
In this letter, we report the regioselective iodocyclization reaction of 3-alkynyl-2-(methylthio)quinolines and 3-alkynyl-2-(methylseleno)quinolines for the synthesis of thieno[2,3–b]quinoline and selenopheno[2,3–b]quinoline derivatives. Further, the resulting halides derivatives were allowed for structural diversification by employing various palladium-catalyzed Sonogashira, Suzuki, and Heck reactions, which can act as the important intermediates for building other valuable compounds. All compounds were fully characterized by the FT-IR, mass, 1H NMR, and 13C NMR spectral data. Finally, the structure of the thieno[2,3–b]quinoline derivative was confirmed by X–ray crystallography. This methodology provided a novel pathway to access quinoline fused heterocycles via iodocyclization reaction. Further, the reaction process was well elucidated by density functional theory calculations.
Organic semiconductors have attracted a lot of attention since the discovery of highly doped conductive polymers, due to the potential application in field-effect transistors (OFETs), light-emitting diodes (OLEDs) and photovoltaic cells (OPVs). Single crystals of organic semiconductors are particularly intriguing because they are free of grain boundaries and have long-range periodic order as well as minimal traps and defects. Hence, organic semiconductor crystals provide a powerful tool for revealing the intrinsic properties, examining the structure–property relationships, demonstrating the important factors for high performance devices and uncovering fundamental physics in organic semiconductors. This review provides a comprehensive overview of the molecular packing, morphology and charge transport features of organic semiconductor crystals, the control of crystallization for achieving high quality crystals and the device physics in the three main applications. We hope that this comprehensive summary can give a clear picture of the state-of-art status and guide future work in this area.
To explore the effect of hydrogen bonding on organic semiconductors, four novel benzo[b]thiophene-benzo[b]furan analogues with contorted configuration were synthesized and exhibited good solubility in normal solvents. The optical, electrochemical characteristics and DFT simulated calculations demonstrates that the configuration feature of molecule plays an important role in modulating the π-conjugated delocalized degree. The X-ray crystallography further revealed the significant effect of hydrogen bonding on the planarity and aggregation mode of the molecular solid-state structure. The single-crystalline field effect transistor (FET) devices were fabricated and both compounds exhibit excellent FET performance with mobility over 0.8 cm²V⁻¹s⁻¹. All the results suggest that it would be an effective method to balance the solubility and electrical properties of organic π-conjugated compounds through regulating the molecular configuration by introduction of the hydrogen bonds.
A new class of nitrogen-containing polycyclic aromatic hydrocarbons (N-PAHs) based on naphthalene-fused triazatruxenes, named as TATNaCn (n = 1-3), were successfully designed, synthesized and characterized. During the oxidative cyclodehydrogenation, multiple dehydrocyclization molecules can be effectively separated apart in a single reaction, implying a stepwise ring-closed process. A combination of thermal, optical, and electrochemical characterization of these stepwise ring-closed N-PAHs was conducted to explore the influence of the ring fused process on the optoelectronic characteristics of N-PAHs. The absorption bands of the fused products TATNaCn are red-shifted compared to those of the TATNa precursor both in dilute solution and thin solid films, suggesting enlarged π-conjugation induced by the fused rings. Furthermore, the band-gap energies of these N-PAHs are facilely modulated with varying the number of closed rings, leading to tunable emission characteristics. The way of introducting triazatruxenes to construct N-PAHs provides a general guideline for exploring novel heteroatom-doped PAHs with facilely tunable optoelectronic properties.
The straightforward synthesis of rigid fused thienoacenes through FeCl3 mediated Scholl cylcodehydrogenation by utilizing thieno[3, 2-b]thiophene as core and alkylthiophenes (alkyloxylphenyls) as arms is described. Their thermal behaviours were studied by different techniques such as thermo-gravimetric analysis, differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. Their self-assembly properties were systematically investigated by variable concentration NMR, scanning electron microscopy and transmission electron microscopy. These new discotic mesogens have very good thermal stability and display thermo-tropic liquid crystalline behaviours. Ordered columnar liquid crystalline phases and crystalline phases were observed for these compounds with tunable phase transition temperatures and mesophase widths. Interestingly, these compounds could simultaneously generate micro-ribbons in various solvents due to strong π-π intermolecular interactions.
The title compound, C20H10S, contains discrete molecules which are essentially planar and are regularly stacked along the b axis [interplanar separation 3.474 (4) Angstrom]; columns are bridged by short S ... S interstack contacts of 3.506 (2) Angstrom about inversion centres.
Organic nanowires self-assembled from small-molecule semiconductors and conducting polymers have attracted an enormous amount of interest for use in organic field-effect transistors. This new class of materials offers solution processability, the potential for elucidating transport mechanisms and structure-property relationships, and the realization of high-performance transistors that rival the performance of amorphous Si. We discuss the self-assembly of one-dimensional, single-crystalline organic nanowires, show the structures of commonly employed organic semiconductors, and review some of the advances in this field.
Micrometer sized single crystalline ribbons of a Se-heterocyclic annelated perylene were prepared by drop casting and physical vapor transport techniques. The crystals of the Se-heterocyclic annelated perylene showed near planar molecular conformation, which regularly stacked along b-axis with Se...Se contacts at 3.49 A˚. Single crystal transistors of individual ribbon were fabricated by ``gold layer glue'' technique. Over 90% transistors exhibited mobility >1.6 cm2 V-1 s-1, the highest mobility approaching 2.66 cm2 V-1 s-1. The top performance indicated the bright prospect of this material in organic electronics.
Chemical-level details such as protonation and hybridization state are critical for understanding enzyme mechanism and function. Even at high resolution, these details are difficult to determine by X-ray crystallography alone. The chemical shift in NMR spectroscopy, however, is an extremely sensitive probe of the chemical environment, making solid-state NMR spectroscopy and X-ray crystallography a powerful combination for defining chemically detailed three-dimensional structures. Here we adopted this combined approach to determine the chemically rich crystal structure of the indoline quinonoid intermediate in the pyridoxal-5'-phosphate-dependent enzyme tryptophan synthase under conditions of active catalysis. Models of the active site were developed using a synergistic approach in which the structure of this reactive substrate analogue was optimized using ab initio computational chemistry in the presence of side-chain residues fixed at their crystallographically determined coordinates. Various models of charge and protonation state for the substrate and nearby catalytic residues could be uniquely distinguished by their calculated effects on the chemical shifts measured at specifically (13)C- and (15)N-labeled positions on the substrate. Our model suggests the importance of an equilibrium between tautomeric forms of the substrate, with the protonation state of the major isomer directing the next catalytic step.
Figure Presented Twisted up: Perchlorination of perylene diimide afforded an exceptionally electron-poor organic semiconductor molecule (see picture; C black, Cl green, O red, N blue, H white) that crystallizes in an ideal brickstone arrangement with close π-π and chlorine-chlorine contacts. Vapor-deposited thin films of this molecule show excellent transistor performance, even in air (μ≈08 cm2V-1 s -1, lon /loff≈108).
The synthesis of a single-crystalline submicrometer-sized ribbons of copper phthalocyanine (CuPc) and fabrication of organic field effect transistor (OFET) devices based on individual submicrometer-sized ribbons, were analyzed. CuPc submicrometer-sized ribbons have been synthesized by physical vapor transport with β-CuPc powder as the starting material. OFET devices based on individual single-crystalline submicrometer-sized ribbons have been fabricated on Si/SiO2 substrates. The results show that CuPc submicrometer-sized ribbons exhibit excellent flexibility and compatibility with conventional Si technology, which is indicative of the great potential of these devices for applications in the future.
Bis(benzo[4,5]thieno)[3,2‐ c :2′,3′‐ e ][1,2]dithiin, ein Valenzisomer von „Dithioxo‐thioindigo”︁
3‐Mercaptobenzo[b]thiophene (1) is transformed with assistance of bases, especially of amines, into the benzo[ b ]‐thieno‐annellated 1,2‐dithiine 6 and not into the originally claimed “Dithioxo‐thioindigo” trans ‐ 3. Primarily, the formation of 6 from 1 involves oxidation to the disulfide 4 which may also be used separately. Conceivable rationalizations are discussed. The same compound is accessible (in lower yield)by thionation of thioindigo with the aid of the Lawesson reagent. X‐ray elucidation of 6 reveals a non‐planar structure of the cyclic disulfide with a dihedral CSSC‐angle of 53°. Despite of the absence of any established chromonphoric moiety, 6 is deeply red in the crystal and in solution, as it is representative for the “undisturbed” 1,2‐dithiine system. Contrary to the usual behaviour of the non‐annellated 1,2‐dithiines, 6 displays no spontaneous sulfur extrusion under mild conditions, but only at high temperatures and in the presence of sulfur‐binding agents, leading to the benzo[ b ]thieno‐annellated thiophene 22. Moreover, 6 may be reduced to the dithiol 14 (or 13 , respectively) and regenerated exclusively from this by oxidation. Further characteristic reactions of 6 are described (e.g. to the sulfoxide 18 , to the pyridazine 19 , and to the thiphosphoric ester 21 ).
The use of micrometer and nanometer-sized organic single crystals to fabricate devices can retain all the advantages of single crystals, avoid the difficulties of growing large crystals, and provide a way to characterize organic semiconductors more efficiently. Moreover, the effective use of such “small” crystals will be beneficial to nanoelectronics. Here we review the recent progress of organic single-crystalline transistors based on micro-/nanometer-sized structures, namely fabrication methods and related technical issues, device properties, and current challenges.
The properties of single-crystalline microribbons of triisopropylsilyethynyl pentacene (TIPS-PEN) were analyzed using solution-phase self-assembly. The TIPS-PEN powder acted as the starting material for the TIPS-PEN microribbons in the solution phase. The induction of a small amount of concentrated toluene solution of TIPS-PEN into acetonitrile led to the formation of nanocrystals and the growth of a microribbon in the closed chamber. The presence of an elevated solvent vapor pressure helped in the spontaneous organization of TIPS-PEN molecules into 1D microribbons. The field-effect properties of OFET were measured by the fabrication of TIPS-PEN microribbons on silica substrates. The solvent exchange method proved to be feasible for the fabrication of OFET based on microribbons, which showed excellent performance and high mobility. Results show that the approach can be useful for optoelectronic applications.
The investigation of the solid-state order of pentacene reveals "herringbone" packing with a combination of edge-to-face and face-to-face molecular interactions. This packing arrangement yields limited π-orbital overlap and may limit the field-effect mobility possible in pentacene. This paper reports on organic thin-film transistors (OTFTs) fabricated with pentacene functionalized to improve π-orbital overlap.
With the advent of devices based on single crystals, the performance of organic field-effect transistors has experienced a significant leap, with mobility now in excess of 10 cm2 V−1 s−1. The purpose of this review is to give an overview of the state-of-the-art of these high-performance organic transistors. The paper focuses on the problem of parameter extraction, limitations of the performance by the interfaces, which include the dielectric–semiconductor interface, and the injection and retrieval of charge carriers at the source and drain electrodes. High-performance devices also constitute tools of choice for investigating charge transport phenomena in organic materials. It is shown how the combination of field-effect measurements with other electrical characterizations helps in elucidating this still unresolved issue.
A method for the enantioselective synthesis of biphenols from readily prepared 1,4-diketones is reported. Key to the success of this method is the highly selective transfer of central to axial chirality during a double aromatization event triggered by BF3·OEt2. On the basis of X-ray crystallographic data, a stereochemical model for this chirality exchange process is put forth.
Rhenium is an important alloying agent in catalytic materials and superalloys, but the experimental and computational data on its binary alloys are sparse. Only 6 out of 28 Re transition-metal systems are reported as compound-forming. Fifteen are reported as phase-separating, and seven have high-temperature disordered σ or χ phases. Comprehensive high-throughput first-principles calculations predict stable ordered structures in 20 of those 28 systems. In the known compound-forming systems, they reproduce all the known compounds and predict a few unreported ones. These results indicate the need for an extensive revision of our current understanding of Re alloys through a combination of theoretical predictions and experimental validations. The following systems are investigated: AgRe(★), AuRe(★), CdRe(★), CoRe, CrRe(★), CuRe(★), FeRe, HfRe, HgRe(★), IrRe, MnRe, MoRe, NbRe, NiRe, OsRe, PdRe, PtRe, ReRh, ReRu, ReSc, ReTa, ReTc, ReTi, ReV, ReW(★), ReY, ReZn(★), and ReZr ((★) = systems in which the ab initio method predicts that no compounds are stable).
The construction of a new class of compounds--the hangman corroles--is provided efficiently by the modification of macrocyclic forming reactions from bilanes. Hangman cobalt corroles are furnished in good yields from a one-pot condensation of dipyrromethane with the aldehyde of a xanthene spacer followed by metal insertion using microwave irradiation. In high oxidation states, X-band EPR spectra and DFT calculations of cobalt corrole axially ligated by chloride are consistent with the description of a Co(III) center residing in the one-electron oxidized corrole macrocycle. These high oxidation states are likely accessed in the activation of O-O bonds. Along these lines, we show that the proton-donating group of the hangman platform works in concert with the redox properties of the corrole to enhance the catalytic activity of O-O bond activation. The hangman corroles show enhanced activity for the selective reduction of oxygen to water as compared to their unmodified counterparts. The oxygen adduct, prior to oxygen reduction, is characterized by EPR and absorption spectroscopy.
Tin-doped indium oxide (ITO) has found widespread use in solar cells, displays, and touch screens as a transparent electrode; however, two major problems with ITO remain: high reflectivity (up to 10%) and insufficient flexibility. Together, these problems severely limit the applications of ITO films for future optoelectronic devices. In this communication, we report the fabrication of ITO nanofiber network transparent electrodes. The nanofiber networks show optical reflectivity as low as 5% and high flexibility; the nanofiber networks can be bent to a radius of 2 mm with negligible changes in the sheet resistance.
Multichromophoric arrays provide one strategy for assembling molecules with intense absorptions across the visible spectrum but are generally focused on systems that efficiently produce and manipulate singlet excitations and therefore are burdened by the restrictions of (a) unidirectional energy transfer and (b) limited tunability of the lowest molecular excited state. In contrast, we present here a multichromophoric array based on four boron dipyrrins (BODIPY) bound to a platinum benzoporphyrin scaffold that exhibits intense panchromatic absorption and efficiently generates triplets. The spectral complementarity of the BODIPY and porphryin units allows the direct observation of fast bidirectional singlet and triplet energy transfer processes (k(ST)((1)BDP→(1)Por) = 7.8 × 10(11) s(-1), k(TT)((3)Por→(3)BDP) = 1.0 × 10(10) s(-1), k(TT)((3)BDP→(3)Por) = 1.6 × 10(10) s(-1)), leading to a long-lived equilibrated [(3)BDP][Por]⇌[BDP][(3)Por] state. This equilibrated state contains approximately isoenergetic porphyrin and BODIPY triplets and exhibits efficient near-infrared phosphorescence (λ(em) = 772 nm, Φ = 0.26). Taken together, these studies show that appropriately designed triplet-utilizing arrays may overcome fundamental limitations typically associated with core-shell chromophores by tunable redistribution of energy from the core back onto the antennae.
We report an interesting approach for efficient synthesis of SnO(2) hollow spheres inside mesoporous silica "nanoreactors". The as-prepared products are shown to have a uniform size distribution and good structural stability. When evaluated for their lithium storage properties, these SnO(2) hollow spheres manifest improved capacity retention.
We present evidence for a near-resonant mechanism of charge transfer in short peptide nucleic acid (PNA) duplexes obtained through electrochemical, STM break junction (STM-BJ), and computational studies. A seven base pair (7-bp) PNA duplex with the sequence (TA)(3)-(XY)-(TA)(3) was studied, in which XY is a complementary nucleobase pair. The experiments showed that the heterogeneous charge transfer rate constant (k(0)) and the single-molecule conductance (σ) correlate with the oxidation potential of the purine base in the XY base pair. The electrochemical measurements showed that the enhancement of k(0) is independent, within experimental error, of which of the two PNA strands contains the purine base of the XY base pair. 7-bp PNA duplexes with one or two GC base pairs had similar measured k(0) and conductance values. While a simple superexchange model, previously used to rationalize charge transfer in single stranded PNA (Paul et al. J. Am. Chem. Soc. 2009, 131, 6498-6507), describes some of the experimental observations, the model does not explain the absence of an enhancement in the experimental k(0) and σ upon increasing the G content in the duplexes from one to two. Moreover, the superexchange model is not consistent with other studies (Paul et al. J. Phys. Chem. B 2010, 114, 14140), that showed a hopping charge transport mechanism is likely important for PNA duplexes longer than seven base pairs. A quantitative computational analysis shows that a near-resonant charge transfer regime, wherein a mix of superexchange and hopping mechanisms are expected to coexist, can rationalize all of the experimental results.
Presented here is a centrally controlled, automated parahydrogen-based polarizer with in situ detection capability. A 20% polarization, corresponding to a 5,000,000-fold signal enhancement at 48 mT, is demonstrated on 2-hydroxyethyl-1-(13)C-propionate-d(2,3,3) using a double-tuned antenna and pulsed polarization transfer. In situ detection is a refinement of first-generation devices enabling fast calibration of rf pulses and B(0), quality assurance of hyperpolarized contrast agents, and stand-alone operation without the necessity of high-field MR spectrometers. These features are essential for biomedical applications of parahydrogen-based hyperpolarization and for clinical translation. We demonstrate the flexibility of the device by recording (13)C signal decay due to longitudinal relaxation of a hyperpolarized contrast agent at 48 mT corresponding to 2 MHz proton frequency. This appears to be the longest recorded T(1) (101 ± 7 s) for a (13)C hyperpolarized contrast agent in water.
Direct radical addition reactions at the C(8)-site of 2'-deoxyguanosine (dG) can afford C(8)-Ar-dG adducts that are produced by carcinogenic arylhydrazines, polycyclic aromatic hydrocarbons, and certain phenolic toxins. Such modified nucleobases are also highly fluorescent for sensing applications and possess useful electron transfer properties. The site-specific synthesis of oligonucleotides containing the C(8)-Ar-G adduct can be problematic. These lesions are sensitive to acids and oxidants that are commonly used in solid-phase DNA synthesis and are too bulky to be accepted as substrates for enzymatic synthesis by DNA polymerases. Using the Suzuki-Miyaura cross-coupling reaction, we have synthesized a number of C(8)-Ar-G-modified oligonucleotides (dimers, trimers, decamers, and a 15-mer) using a range of arylboronic acids. Good to excellent yields were obtained, and the reaction is insensitive to the nature of the bases flanking the convertible 8-Br-G nucleobase, as both pyrimidines and purines are tolerated. The impact of the C(8)-Ar-G lesion was also characterized by electrospray ionization tandem mass spectrometry, UV melting temperature analysis, circular dichroism, and fluorescence spectroscopy. The C(8)-Ar-G-modified oligonucleotides are expected to be useful substrates for diagnostic applications and understanding the biological impact of the C(8)-Ar-G lesion.
High performance p-channel transistors based on a single-crystal organic microribbon self-assembled through a solution process, are achieved by enhancing the crystallinity, improving the interface between the dielectric and the crystal, shrinking the channel length, and realizing asymmetric metal electrodes for source and drain (see figure). The highest mobility reached is 2.1Cm 2V-1S-1 with an on/off ratio of 2 x 10 5 and a threshold voltage of-7 V. (Figure Presented)
Charge carrier mobility is at the center of organic electronic devices. The strong couplings between electrons and nuclear motions lead to complexities in theoretical description of charge transport, which pose a major challenge for the fundamental understanding and computational design of transport organic materials. This tutorial review describes recent progresses in developing computational tools to assess the carrier mobility in organic molecular semiconductors at the first-principles level. Some rational molecular design strategies for high mobility organic materials are outlined.
Crystalline self-assembled monolayers (SAMs) of organosilane compounds such as octadecyltrimethoxysilane (OTMS) and octadecyltrichlorosilane (OTCS) were deposited by a simple, spin-casting technique onto Si/SiO(2) substrates. Fabrication of the OTMS SAMs and characterization using ellipsometry, contact angle, atomic force microscopy (AFM), grazing angle attenuated total reflectance Fourier transform infrared (GATR-FTIR) spectroscopy and grazing incidence X-ray diffraction (GIXD) are described. The characterization confirms that these monolayers exhibit a well-packed crystalline phase and a remarkably high degree of smoothness. Semiconductors deposited by vapor deposition onto the crystalline OTS SAM grow in a favorable two-dimensional layered growth manner which is generally preferred morphologically for high charge carrier transport. On the OTMS SAM treated dielectric, pentacene OFETs showed hole mobilities as high as 3.0 cm(2)/V x s, while electron mobilities as high as 5.3 cm(2)/V x s were demonstrated for C(60).
The development of solution-processable, high-performance n-channel organic semiconductors is crucial to realizing low-cost, all-organic complementary circuits. Single-crystalline organic semiconductor nano/microwires (NWs/MWs) have great potential as active materials in solution-formed high-performance transistors. However, the technology to integrate these elements into functional networks with controlled alignment and density lags far behind their inorganic counterparts. Here, we report a solution-processing approach to achieve high-performance air-stable n-channel organic transistors (the field-effect mobility (mu) up to 0.24 cm(2)/Vs for MW networks) comprising high mobility, solution-synthesized single-crystalline organic semiconducting MWs (mu as high as 1.4 cm(2)/Vs for individual MWs) and a filtration-and-transfer (FAT) alignment method. The FAT method enables facile control over both alignment and density of MWs. Our approach presents a route toward solution-processed, high-performance organic transistors and could be used for directed assembly of various functional organic and inorganic NWs/MWs.
A practical strategy for the preparation of a series of heterocyclic annulated perylenes in good yields is presented. UV-vis absorption spectra indicate hypsochromic shift of the absorption maxima relative to the corresponding parent perylene. Single-crystal X-ray diffraction analysis reveals that they all adopt planar conformation, but the solid-state packing arrangements are significantly altered by annulation of various heterocycles.
Single-crystal field effect transistors of the organic semiconductor dithiophene-tetrathiafulvalene (DT-TTF) were prepared by drop casting. Long, thin crystals connected two microfabricated gold electrodes, and a silicon substrate was used as a back gate. The highest hole mobility observed was 1.4 cm2/Vs, which is the highest reported for an organic semiconductor not based on pentacene. A high ON/OFF ratio of at least 7 x 105 was obtained for this device.
The substitution of chloro or bromo groups in tetracene gives rise to the change of crystal structure, having a substantial effect on carrier transport. Halogenated tetracene derivatives were synthesized and grown into single crystals. Monosubstituted 5-bromo- and 5-chlorotetracenes have the herringbone-type structure, while 5,11-dichlorotetracene has the slipped pi stacking structure. Mobility of 5,11-dichlorotetracene was measured to be as high as 1.6 cm2/V.s in single-crystal transistors. The pi stacking structure, which enhances pi orbital overlap and facilitates carrier transport, may thus be responsible for this high mobility.
We present the device parameters for organic field-effect transistors fabricated from solution-deposited films of functionalized pentacene and anthradithiophenes. These materials are easily prepared in one or two steps from commercially available starting materials and are purified by simple recrystallization. For a solution-deposited film of functionalized pentacene, hole mobility of 0.17 cm2/V.s was measured. The functionalized anthradithiophenes showed behavior strongly dependent on the substituents, with hole mobilities as high as 1.0 cm2/V.s.
[reaction: see text] A new intramolecular triple cyclization of bis(o-haloaryl)diacetylenes, via dilithiation followed by reaction with chalcogen elements, produces pi-conjugated compounds containing heterole-1,2-dichalcogenin-heterole fused tricyclic skeletons. The subsequent dechalcogenation with copper metal affords a series of thiophene- and selenophene-based heteroacenes.
Theoretical investigations of charge transport in organic materials are generally based on the "energy splitting in dimer" method and routinely assume that the transport parameters (site energies and transfer integrals) determined from monomer and dimer calculations can be reliably used to describe extended systems. Here, we demonstrate that this transferability can fail even in molecular crystals with weak van der Waals intermolecular interactions, due to the substantial (but often ignored) impact of polarization effects, particularly on the site energies. We show that the neglect of electronic polarization leads to qualitatively incorrect values and trends for the transfer integrals computed with the energy splitting method, even in simple prototypes such as ethylene or pentacene dimers. The polarization effect in these systems is largely electrostatic in nature and can change dramatically upon transition from a dimer to an extended system. For example, the difference in site energy for a prototypical "face-to-edge" one-dimensional stack of pentacene molecules is calculated to be 30% greater than that in the "face-to-edge" dimer, whereas the site energy difference in the pentacene crystal is vanishingly small. Importantly, when computed directly in the framework of localized monomer orbitals, the transfer integral values for dimer and extended systems are very similar.
This study details a new derivative of the contorted HBCs that self-organizes into one-dimensional, single-crystalline fibers. X-ray diffraction, transmission electron microscopy, and electron diffraction studies show that they have an orthorhombic unit cell with dimensions of 5.8 nm x 4.5 nm x 0.45 nm. Each fiber is composed of a few thousands columns. A method is put forth that utilizes elastomer stamps to manipulate and position isolated fibers in organic field effect transistors.
High-performance air-stable n-type field-effect transistors based on single-crystalline submicro- and nanometer ribbons of copper hexadecafluorophthalocyanine (F(16)CuPc) were studied by using a novel device configuration. These submicro- and nanometer ribbons were synthesized by a physical vapor transport technique and characterized by the powder X-ray diffraction pattern and selected area electron diffraction pattern of transmission electron microscopy. They were found to crystallize in a structure different from that of copper phthalocyanine. These single-crystalline submicro- and nanometer ribbons could be in situ grown along the surface of Si/SiO(2) substrates during synthesis. The intimate contact between the crystal and the insulator surface generated by the "in situ growing process" was free from the general disadvantages of the handpicking process for the fabrication of organic single-crystal devices. High performance was observed in devices with an asymmetrical drain/source (Au/Ag) electrode configuration because in such devices a stepwise energy level between the electrodes and the lowest unoccupied molecular orbital of F(16)CuPc was built, which was beneficial to electron injection and transport. The field-effect mobility of such devices was calculated to be approximately 0.2 cm(2) V(-)(1) s(-)(1) with the on/off ratio at approximately 6 x 10(4). The performances of the transistors were air stable and highly reproducible.
In this communication we report the electrical characteristics of hexathiapentacene (HTP) and emphasize the unusual chemical structure and molecular packing. We report field-effect mobilities as high as 0.04 cm2 V-1 s-1 and current on/off ratios of >105. With crystallographic evidence of unusually long S-S bonds compared to normal S-S bonds, we have suggested a unique resonance structure similar to trithiapentalene, which well explains the bonding characteristics of HTP. This work appears to be the first to determine its molecular structure/packing mode and to study its application in organic transistors.
We have first investigated the thin-film field-effect behavior of perylo[1,12-b,c,d]thiophene by vacuum evaporation technique, which exhibits a moderate mobility of 0.05 cm(2) V-1 s(-1), an on/off ratio of 10(5), and a low threshold voltage of -6.3 V at room temperature. Moreover, we have grown its single-crystalline micrometer wires and successfully applied them to transistors. A high mobility up to 0.8 cm(2) V-1 s(-1) has been achieved. The extraordinary solid-state packing arrangement with the likelihood of double-channel fashion induced by marked S center dot center dot center dot S interactions may contribute to the high performance.
This paper describes a simple, solution-phase route to the synthesis of bulk quantities of hexathiapentacene (HTP) single-crystal nanowires. These nanowires have also been successfully incorporated as the semiconducting material in field-effect transistors (FETs). For devices based on single nanowires, the carrier mobilities and current on/off ratios could be as high as 0.27 cm2/Vs and >103, respectively. For transistors fabricated from a network of nanowires, the mobilities and current on/off ratios could reach 0.057 cm2/Vs and >104, respectively. We have further demonstrated the use of nanowire networks in fabricating transistors on mechanically flexible substrates. Preliminary results show that these devices could withstand mechanical strain and still remain functional. The results from this study demonstrate the potential of utilizing solution-dispersible, nanostructured organic materials for use in low-cost, flexible electronic applications.
In this review, we have discussed the major advances that have recently been achieved in the description of the parameters impacting charge transport in organic semi-conductors. Once again, the picture emerging in organic semiconductors appears to be more complex than in conventional inorganic semiconductors; this was the case already when comparing the electronic structure of these materials: while inorganic semiconductors can usually be well described via one-electron (band structure) approaches, organic semi-conductors often require a treatment that takes both electron-electron and electron-phonon interactions into account. In the case of transport, we emphasized in sections 3 and 4 some of the shortcomings of the current models used to depict organic semiconductors and the paths to be followed to achieve significant improvements. An important element is that it has become clear that organic semiconductors require that both local and nonlocal electron-phonon couplings be considered. Thus, we can conclude that a comprehensive understanding will come from the development of models allowing the calculations of the vibrational couplings: (i) with all modes, optical as well as acoustical since the actual strength of acoustic-type nonlocal interactions is not well-established yet; (ii) at a high level of theory; and (iii) over a much larger range of systems than those that have been examined to date. We hope that this review will provide the impetus for these calculations to be undertaken.
Perylenetetracarboxyldiimide (PTCDI) nanowires self-assembled from commercially available materials are demonstrated as the n-channel semiconductor in organic field-effect transistors (OFETs) and as a building block in high-performance complementary inverters. Devices based on a network of PTCDI nanowires have electron mobilities and current on/off ratios on the order of 10(-2) cm2/Vs and 10(4), respectively. Complementary inverters based on n-channel PTCDI nanowire transistors and p-channel hexathiapentacene (HTP) nanowire OFETs achieved gains as high as 8. These results demonstrate the first example of the use of one-dimensional organic semiconductors in complementary inverters.
A condensed benzothiophene peripherally carrying rich sulfur atoms favoring pi-pi stacking is developed through facile approaches. The (1)H NMR and the absorption spectra strongly indicate that this molecule easily forms the self-assembled structures in solutions. Microwires directly precipitate from solution, and such 11) self-assembled nano- and microstructures can be controlled and tuned by changing solvents and casting on various substrates. Single microwire transistor based on such condensed benzothiophene is easily fabricated through solution process with carrier mobility as high as 0.01 cm(2) V(-1) S(-1).
A novel heptacyclic bisindoloquinoline-based organic semiconductor has been synthesized, characterized, and used to fabricate single-crystal field-effect transistors. A synthetic route was developed for the synthesis of heptacyclic bis(indolo(1,2-a))quinoline via an intramolecular cyclization of anthrazoline derivatives. Single-crystal X-ray structure revealed that the seven fused rings of bis(indolo(1,2-a))quinoline are relatively coplanar and lead to slipped face-to-face stacking with the shortest intermolecular spacing of 3.3 angstrom. Single-crystal field-effect transistors based on the bis(indolo(1,2-a))quinoline had carrier mobility as high as 1.0 cm(2)/V s with on/off ratios greater than 10(4).
Single-crystalline, precise size-controlled nanowires and ultralong microwires with lengths reaching several millimeters of organic semiconductor 1 were prepared in large scale by cast assembly. The size and density of the nanowires and microwires could be controlled by simply adjusting the concentration of 1 in casting solutions. More importantly, the formation of these nanowires and microwires showed no substrate and solvent dependence and was orientation controllable. Highly reproducible and sensitive photo response characteristics were observed in these nanowires and microwires. Fast and reversible photoswitchers based on multiple or individual single-crystal microwires were fabricated via "multi times gold wire mask moving" technique with switch ratio over 100.
Photoinduced electron transfer (ET) in zinc-substituted cytochrome c (Zn-cyt c) has been utilized in many studies on the long-range ET in protein. Attempting to understand its ET mechanism in terms of electronic structure of the molecule, we have calculated an all-electron wave function for the ground-state of Zn-cyt c on the basis of density functional theory (DFT). The four molecular orbitals (MOs) responsible for excitation by UV-vis light (Gouterman's 4-orbitals) are assigned on the basis of the excited states of chromophore model for Zn-porphine complex calculated with the time-dependent DFT method. ET rates between each Gouterman's 4-orbitals and other MOs were estimated using Fermi's golden rule. It appeared that the two occupied MOs of the 4-orbitals show exclusively higher ET rate from/to particular MOs that localize on outermost amino acid residues (Lys 7 or Asn 54), respectively, whereas ET rates involving the two unoccupied MOs of the 4-orbitals are much slower. These results imply that the intramolecular ET in photoexcited Zn-cyt c is governed by the hole transfer through occupied MOs. The couplings of MOs between zinc porphyrin core and specific amino acid residues on the protein surface have been demonstrated in Zn-cyt c immobilized on an Au electrode via carboxylic acid group-terminated self-assembled monolayer. The Zn-cyt c-modified electrode showed photocurrents responsible for photoillumination. The action spectrum of the photocurrent was identical with the absorption spectrum of Zn-cyt c, indicating photoinduced electron conduction via occupied MOs. The voltage dependence of the photocurrent appeared to be linear and bidirectional like a photoconductor, which strongly supports the intramolecular ET mechanism in Zn-cyt c proposed on the basis of the theoretical calculations.
In general, fabrication of well-defined organic nanowires or nanobelts with controllable size and morphology is not as advanced as for their inorganic counterparts. Whereas inorganic nanowires are widely exploited in optoelectronic nanodevices, there remains considerable untapped potential in the one-dimensional (1D) organic materials. This Account describes our recent progress and discoveries in the field of 1D self-assembly of planar π-conjugated molecules and their application in various nanodevices including the optical and electrical sensors. The Account is aimed at providing new insights into how to combine elements of molecular design and engineering with materials fabrication to achieve properties and functions that are desirable for nanoscale optoelectronic applications. The goal of our research program is to advance the knowledge and develop a deeper understanding in the frontier area of 1D organic nanomaterials, for which several basic questions will be addressed: (1) How can one control and optimize the molecular arrangement by modifying the molecular structure? (2) What processing factors affect self-assembly and the final morphology of the fabricated nanomaterials; how can these factors be controlled to achieve the desired 1D nanomaterials, for example, nanowires or nanobelts? (3) How do the optoelectronic properties (e.g., emission, exciton migration, and charge transport) of the assembled materials depend on the molecular arrangement and the intermolecular interactions? (4) How can the inherent optoelectronic properties of the nanomaterials be correlated with applications in sensing, switching, and other types of optoelectronic devices?
Markovnikov Intermolecular Hydroalkoxylation of Terminal Acetylenes Masataka Kondo, Takuya Kochi
- Rhodium
- Anti
Rhodium-Catalyzed Anti-Markovnikov Intermolecular Hydroalkoxylation of Terminal Acetylenes Masataka Kondo, Takuya Kochi, Fumitoshi Kakiuchi Journal of the American Chemical Society 2011 133 (1), 32-34
Control of the Helix Structure and Enhanced Differential Binding to Immune Cells Iria M. Rio-Echevarria, Regina Tavano
- Water-Soluble
- Peptide
- Nanoparticles
Water-Soluble Peptide-Coated Nanoparticles: Control of the Helix Structure and Enhanced Differential Binding to Immune Cells Iria M. Rio-Echevarria, Regina Tavano, Valerio Causin, Emanuele Papini, Fabrizio Mancin, Alessandro Moretto Journal of the American Chemical Society 2011 133 (1), 8-11
Ordered Structures in Rhenium Binary Alloys from First-Principles Calculations Ohad Levy
- Roman V Jahn Tek
- Gus L W Chepulskii
- Hart
Ordered Structures in Rhenium Binary Alloys from First-Principles Calculations
Ohad Levy, Michal Jahn tek, Roman V. Chepulskii, Gus L. W. Hart, Stefano Curtarolo
Journal of the American Chemical Society 2011 133 (1), 158-163
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