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![FIG. 1. Photographs of 2D [CH 3 (CH 2 ) 3 NH 3 ] 2 (CH 3 NH 3 )Pb 2 I 7...](profile/Ridwan-Fayaz-Hossain-Phd/publication/343426503/figure/fig1/AS:928043447095297@1598274208801/Photographs-of-2D-CH-3-CH-2-3-NH-3-2-CH-3-NH-3-Pb-2-I-7-perovskite-crystals-in_Q320.jpg)
Two-dimensional (2D) halide perovskites have recently drawn significant interest due to their excellent optoelectronic and photoabsorption properties. Here, we present the large scale synthesis of solution-processed 2D (CH3(CH2)3NH3)2(CH3NH3)n − 1PbnI3n + 1 (n = 2, 3, and 4) perovskites, a family of layered compounds with composition-tunable bandga...
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Context 1
... 44-47 Figure 3 shows the XRD spectra of 2D perovskite films for n = 2, 3, and 4. The 2D network is consistent with an inorganic layer of corner-sharing [Pb n I 3n + 1 ] 4− octahedral confined between an interdigitating bilayer of an intercalated organic layer as bulk alkylammonium cations. 40 The separation of the inorganic layers results in an increase of the lattice constants as the incorporation of the BA spacers requires a gap of ∼7.8 Å between the perovskite layers; the simplest case of n = 1 has a thickness of ∼6.4 Å, which roughly corresponds to the sum of the two Pb-I bond lengths. ...
Context 2
... 44-47 Figure 3 shows the XRD spectra of 2D perovskite films for n = 2, 3, and 4. The 2D network is consistent with an inorganic layer of corner-sharing [Pb n I 3n + 1 ] 4− octahedral confined between an interdigitating bilayer of an intercalated organic layer as bulk alkylammonium cations. 40 The separation of the inorganic layers results in an increase of the lattice constants as the incorporation of the BA spacers requires a gap of ∼7.8 Å between the perovskite layers; the simplest case of n = 1 has a thickness of ∼6.4 Å, which roughly corresponds to the sum of the two Pb-I bond lengths. ...
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Citations
... Though extensive research work was carried out on the fabrication of highly responsive photodetectors based on 2D MHLP single crystal materials, only few reports can be found in the form of inks that can be directly used for the printable photonic applications. For instance, Min et al., [248] showed photoresponsivity of 21 mA/W at a low light intensity of F ∼ 0.6 mW/cm 2 by using the solution-processed 2D (BA)2(MA)Pb2I7 material that are responsive for the broad range of incoming radiation in the visible region. Inkjet printed (BA)2(MA)3Pb4I13 ...
Functional inks based on two-dimensional (2D) materials have potential application in building new and commercially viable photonic devices via different printing techniques. Printed photonics using 2D material-based inks brings together the unique optical properties of 2D materials via different printing techniques for fabricating photonic devices that can revolutionize various sectors in telecommunication, information technology, sensors and computing. Understanding the need for a comprehensive guide for researchers in the field of printed photonics based on 2D material inks, we have brought together the essential concepts in this field. The review begins with discussion on optical properties of commonly used 2D materials in photonic applications. Since different printing techniques demand different ink rheological properties for efficient printing, we have discussed it for different printing techniques. The substrates compatible for printed photonics application are also listed. Mechanisms of common printing methods in device fabrication are explained with more focus on the most commonly demonstrated method in printed photonics, i.e., inkjet printing. We have discussed a few examples of photonic devices where printed photonics is already demonstrated with 2D material functional inks. Finally, our perspective on future prospects of 2D materials, with excellent optical properties, that are yet to be formulated into inks for new and efficient photonic device fabrication as well as devices with potentially new functionalities are listed.
... Though extensive research work was carried out on the fabrication of highly responsive photodetectors based on 2D MHLP single crystal materials, only few reports can be found in the form of inks that can be directly used for the printable photonic applications. For instance, Min et al., [248] showed photoresponsivity of 21 mA/W at a low light intensity of F ∼ 0.6 mW/cm 2 by using the solution-processed 2D (BA)2(MA)Pb2I7 material that are responsive for the broad range of incoming radiation in the visible region. Inkjet printed (BA)2(MA)3Pb4I13 ...
Functional inks based on two-dimensional (2D) materials have potential application in building new and commercially viable photonic devices via different printing techniques. Printed photonics using 2D material-based inks brings together the unique optical properties of 2D materials via different printing techniques for fabricating photonic devices that can revolutionize various sectors in telecommunication, information technology, sensors and computing. Understanding the need for a comprehensive guide for researchers in the field of printed photonics based on 2D material inks, we have brought together the essential concepts in this field. The review begins with discussion on optical properties of commonly used 2D materials in photonic applications. Since different printing techniques demand different ink rheological properties for efficient printing, we have discussed it for different printing techniques. The substrates compatible for printed photonics application are also listed. Mechanisms of common printing methods in device fabrication are explained with more focus on the most commonly demonstrated method in printed photonics, i.e., inkjet printing. We have discussed a few examples of photonic devices where printed photonics is already demonstrated with 2D material functional inks. Finally, our perspective on future prospects of 2D materials, with excellent optical properties, that are yet to be formulated into inks for new and efficient photonic device fabrication as well as devices with potentially new functionalities are listed.
Electronic and stability properties of quasi-2D alkylammonium perovskites are investigated using density functional theory (DFT) calculations and validated experimentally on selected classes of compounds. Our analysis is focused on perovskite structures of formula (A)2(A')n-1PbnX3n+1, with large cations A = butyl-, pentyl-, hexylammonium (BA, PA, HXA), small cations A' = methylammonium, formamidinium, ethylammonium, guanidinium (MA, FA, EA, GA) and halogens X = I, Br, Cl. The role of the halogen ions is outlined for the band structure, stability and defect formation energies. Two opposing trends are found for the absorption efficiency versus stability, the latter being assessed with respect to possible degradation mechanisms. Experimental validation is performed on quasi-2D perovskites based on pentylammonium cations, namely: (PA)2PbX4 and (PA)2(MA)Pb2X7, synthesized by antisolvent-assisted vapor crystallization. Structural and optical analysis are inline with the DFT based calculations. In addition, the thermogravimetric analysis shows an enhanced stability of bromide and chloride based compounds, in agreement with the theoretical predictions.
The incorporation of high‐precision intelligent manufacturing technologies into patterned metal halide perovskite production has attracted scientific and commercial interest because of advantages in terms of designable and controllable processes, multiscale and multimaterial construction strategies, and improved energy‐conversion performance. Here, the current developments in intelligent manufacturing technologies are reviewed for patterned and tailored perovskite structures. Six high‐precision approaches, namely, nanoimprint lithography, space‐confined growth, ink‐based direct printing, laser‐induced nucleation, modification using a laser, and high‐energy etching, are investigated and summarized. The focus of the review is on the basic principles of intelligent manufacturing methods, process optimization, and controllable perovskite microstructures. Additionally, the performance improvements of patterned and tailored perovskites and their devices, including photodetectors, solar cells, lasers, information storage and encryption devices, anticounterfeiting devices, and full‐color display applications, are discussed. The potential future applications of shaped perovskites fabricated via intelligent manufacturing technologies are promising.
Halide perovskites emerge as attractive materials because of their superior optical and optoelectrical properties. Patterned perovskites are useful because they can maximize the optical and electronic properties of perovskites to thereby enhance optoelectronic devices. However, halide perovskite patterning devices are limited by their instability (caused by lattice strain) and ionic properties (e.g., halide migration). Moreover, it is very difficult to pattern perovskites using common photolithography methods. Researchers have tried to overcome these obstacles by searching for templates or avoiding photoresists or direct patterning techniques. In this article, research into perovskite patterning methods that do not use conventional photolithography is reviewed, and a roadmap for direct optical perovskite patterning research is suggested.
Next-generation optoelectronics with lightweight, low-cost, high flexibility, and large-area compatibility have been developed to conform to soft surfaces, even human skins, to achieve various wearable and portable functionalities. Among them, flexible photodetectors (FPDs) based on metal halide perovskites (MHPs) have become an emerging optoelectronic device due to their tunable optoelectronic properties, excellent light-sensing performance, remarkable mechanical flexibility, and relatively low-temperature solution processability. This review examines the recent advances in FPDs based on MHPs, focusing on both the materials and devices of optoelectronic and mechanical properties, the deposition and patterning technologies, the encapsulation strategies, and their potential applications in conformable electronics. We also discuss the challenges and provide a future perspective on the further applications.
Although there are recent advances in many areas of quasi‐2D halide perovskites, photodetectors based on these materials still cannot achieve satisfactory performance for practical applications where high responsivity, fast response, self‐powered nature, and excellent mechanical flexibility are urgently desired. Herein, utilizing one‐step spin‐coating method, self‐assemble quasi‐2D perovskite films with graded phase distribution in the order of increasing number of metal halide octahedral layers are successfully prepared. Gradient type‐II band alignments along the out‐of‐plane direction of perovskites with spontaneous separation of photo‐generated electrons and holes are obtained and then employed to construct self‐powered vertical‐structure photodetectors for the first time. Without any driving voltage, the device exhibits impressive performance with the responsivity up to 444 mA W⁻¹ and ultrashort response time down to 52 µs. With a bias voltage of 1.5 V, the device responsivity becomes 3463 mA W⁻¹ with the response speed as fast as 24 µs. Importantly, the device's mechanical flexibility is greatly enhanced since the photocurrent prefers flowing through the metal halide octahedral layers between the top and bottom contact electrodes in the vertical device structure, being more tolerant to film damage. These results evidently indicate the potential of graded quasi‐2D perovskite phases for next‐generation optoelectronic devices.
