Content uploaded by Giancarlo C. Righini
Author content
All content in this area was uploaded by Giancarlo C. Righini on Dec 31, 2014
Content may be subject to copyright.
A preview of the PDF is not available
Sol–gel-derived photonic structures handling erbium ions luminescence
Abstract and Figures
The sol–gel technique is a very flexible, relatively simple, and low-cost method to fabricate many different innovative photonic structures characterized by specific functionalities. During synthesis, starting from the molecular level, compounds or composites with well controlled composition can be obtained as thin films, powders or monoliths. These materials can be used to prepare such structures as waveguides, photonic crystals, coatings, and bulk glasses including spheres, rings and other geometries exploited in optical resonators fabrication. This article presents some results obtained by the authors in the field of the sol–gel-derived photonic structures. To emphasise the scientific and technological interest in this kind of systems and the versatility of the sol–gel route, the glass-based nano and micrometer scale range systems are discussed. Particularly, the following systems are described: silica–hafnia glass and glass–ceramic planar waveguides, nanosized tetraphosphates, and silica colloidal crystals. The attention is focused on the spectroscopic properties of \(\hbox {Er}^{3+}\) -activated materials that due to the light emission can be used in the integrated optics area covering application in sensing, biomedical diagnostic, energy conversion, telecommunication, lighting, and photon management.
Figures - uploaded by Giancarlo C. Righini
Author content
All figure content in this area was uploaded by Giancarlo C. Righini
Content may be subject to copyright.
... It is used for synthesizes a lot of materials such as Silica-Phosphate[8], Silica-Hafnia [9] and phosphate glasses [10]. Moreover it offers great possibilities performance, due to the ease of introducing a wide dopants variety [11]. Due to silica unique features such as narrow microscopic size distributions, ultrahigh surface area and highly order structure, until now it remains one of the more useful host materials including high rare earth [RE] solubility with suitable ion bonding [12][13][14]. ...
... due to the energy transferred from Yb 3+ to Ho 3+ ions and by increasing annealing temperature from 300 up to 900 o C the intensity of the peak decreased due to the increase of the thermal treatment causes decrease in defects concentration, the pores disappear and hydroxyl content decreases leading to decrease in thin films intensity peaks [35]. 11 the nanocomposite density increases affecting the high intensity in the red emission peak at 620nm [36]. ...
Nano-composite Phospho-Silicate (SiO 2-P 2 O 5) co-doped with trivalent (Ho 3+) and (Yb 3+) ions, respectively are considered as promising materials for photonic application. The nano-composite samples were prepared and their unique optical spectroscopic and structural properties were studied as a function of constant concentration of Ho 3+ ions at (0.5) mol. % and different concentrations of Yb 3+ ions at (0.5, 0.1 and 1.5) mol. % and elevated temperature. The samples structure was studied using X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Moreover, the crystallite sizes were increased by increasing the Yb 3+ ions concentrations at 900 o C to give the following values 11.7, 16.96 and 33.76 nm for (0.5), (0.1) and (1.5) mol.% of Yb 3+ ions, respectively. Optical studies were measured by using the spectrophotometer in wavelength range 300-2500nm.The refractive index (n) was calculated for the prepared samples, it was found to be strongly affected by structural rearrangement resulting from the elimination of the solvent and it increases by increasing phosphate concentrations and annealing temperature, It was increased from (1.59 to 1.67) and from (1.75 to 1.78) at constant wavelength 550 nm after annealing at 300 and 900 0 C for (0.5, 0.1 and 1.5 mol. % of Yb 3+ ions), respectively. The photoluminescence (PL) confirms that the phospho-silicate could be a promising candidate to be used for up-down-conversion application.
... It is used for synthesizes a lot of materials such as Silica-Phosphate[8],Silica-Hafnia [9] and phosphate glasses [10]. Moreover it offers great possibilities performance, due to the ease of introducing a wide dopants variety [11]. Due to silica unique features such as narrow microscopic size distributions, ultrahigh surface area and highly order structure, until now it remains one of the more useful host materials including high rare earth [RE] solubility with suitable ion bonding [12][13][14]. ...
... Due to silica unique features such as narrow microscopic size distributions, ultrahigh surface area and highly order structure, until now it remains one of the more useful host materials including high rare earth [RE] solubility with suitable ion bonding [12][13][14]. For this reason, it is very interesting to investigate the silica gel doped with P 2 O 5 or halfnia, Where they are interesting hosts for rare earth embedded in fiber amplifier [9,11,15]. The mentioned nano-particles could be very interesting in using it for new applications such as interesting up-down-conversion higher solar cell efficiency and transparent emitting devices elaboration [13,16,17] Our present work optimistic aim is to develop the change in the silica gel structure by adding the phosphate and two different rare earth dopants such as Ho 3+ and Yb 3+ ions in its network trying to obtain up-down-conversion higher solar cell efficiency for the first time from such material to be involved in future industrial applications. ...
... Phosphate P 2 O 5 is an extremely useful co-dopant for silica as it improves the ability of dissolving the rareearth ions and provides desirable spectroscopic properties for Tb 3+ and Ho 3+ ions [1][2][3][4]. In fact, the pure silica is an anomalous host for rare-earth ions which is considered to be an oxide adsorbent [5,6]. ...
... The prepared nanocomposite systems were obtained in two different forms, namely monolithic and thin film. The prepared samples were obtained by hydrolysis and poly-condensation of tetra-ethoxysilane (CH 3 CH 2 OH) 4 [SP1TbM] for monolithic samples. These solutions were then filtered with 0.22 µm of sterilized filter membrane. ...
The use of sol-gel technique to fabricate phospho-silicate nanocomposite SiO2–P2O5 based glasses containing
20 mol.% P2O5 deposited on quartz silica substrate is presented in this work. Particularly, terbium Tb3+ and
holmium Ho3+ ions were doped in the mentioned host matrix. A variety of material studies were carried out for
the investigation of the physical properties of these new materials, such as the Fourier transform infrared and
X-ray diffraction. The X-ray diffraction confirmed that the silica gel crystallization was enhanced as a result of the
phosphorus existence. Moreover, the functional groups of the prepared nanocomposite samples were detected from
the Fourier transform infrared analyses. The morphology of prepared monolith samples was characterized by high
resolution transmission electron microscopy. The surface morphology of both the thin film and monolith samples
were confirmed using field emission scanning electron microscopy.
DOI: 10.12693/APhysPolA.137.1037
PACS/topics: nanocomposite, thin film, phospho-silicate and monolith
... The whole fabrication process flow of the ultra-bend-resistant 4-core SXC can be orderly divided into three parts: preform deposition, fiber drawing and cabling, which are, respectively exhibited in Figure 2. For the preform deposition, in order to avoid the OH-absorption during the manufacture process of the preform as much as possible [18], we used the in-tube chemical vapor deposition with a deep fluorine-doped process for the wave-guided core and the OVD process for the high-purity silica rod, respectively. The original diameter and length of the core preform are 24.89 ...
We optimized and fabricated an ultra-bend-resistant 4-core simplex cable (SXC) employing 4-core multicore fiber (MCF) suitable for short-reach dense spatial division multiplexing (DSDM) optical transmission in the O-band. The characteristics of transmission loss, macro-bending and cross-talk (XT) between adjacent cores after cabling were firstly clarified. By introducing the trapezoid index and optimizing the cabling process, the maximum values of added XT of 1.17 dB/km due to 10 loops with a bending radius of 6 mm imposed over the 4-core SXC and a macro-bending loss of 0.37 dB/10 turns were, respectively, achieved.P Then, the optical transmission with low bit error rate (BER) was presented using a 100GBASE-LR4 transceiver over the 1.2 km long 4-core SXC. The excellent bending resistance of the 4-core SXC may pave the way for a reduction in space pressure and increase in access density on short-reach optical interconnect (OI) based on DSDM.
... It is well known that the erbium solubility in silica matrix is low, however if it is doped with phosphate ions the solubility increases dramatically [7]. Light source producing the optical signal is an important optical integrated circuit (OIC) component, optical waveguide systems transmit, and can process this optical signal, then detector will convert the optical signal back to the electric domain giving rise to ease, low-cost techniques, and offer the integration promise of passive, and active function [8][9][10][11]. That's why Er-doped planer optical waveguide amplifier has much possible usages in transferring optically modulated data over long distances, and signal processing system as integrated appliances [12,13]. ...
Volume 49, Issue 15, 1 August 2023, Pages 25333-25343
... The fabrication of the proposed structure can be divided into two parts. Fiber with specific air hole arrangement can be drawn by conventional stack and draw [35] or sol-gel casting methods [36], while the coating of the plasmon materials can be achieved by chemical vapor deposition approach [37] or pulsed laser deposition technique [38]. It is worth supplying that, although PCF-SPR sensors are of ultra-high wavelength sensitivity, the high confinement loss of the SPP determines that the effective length of such device is usually restricted to several hundred micrometers [11]. ...
This work proposes a novel multi-channel photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) technique where Au-Ta2O5 layer and Ag-Ta2O5 layer are selected as plasmonic materials. Dual-analyte simultaneous measurement can be well implemented by individually monitoring the SPR intensities of the x-polarized and y-polarized modes in the near-infrared region. Using a full-vectorial finite element method (FV-FEM) and COMSOL software, we have theoretically elucidated the effects of related parameters comprising coating thickness and pitch parameter on the sensing response. The optimized results show that the proposed sensor has attended to average wavelength sensitivities of 11,466 nm/RIU and 6833 nm/RIU, with maximum amplitude sensitivities of − 940.1/RIU and − 1008/RIU for channel 1 and channel 2, respectively. A ± 2% structural error of air holes has been taken into consideration and shows little impact on the wavelength sensitivities. Moreover, our sensing response is of excellent linear characters with R² of the polynomial lines up to 0.9983 and 0.9993.
... Photonic systems have aroused growing interest in medical, biological and technological applications, with the use of lasers, sensors, waveguides, optical fibers, lightemitting diodes, among others (Kajihara, 2013;Bouras et al., 2014;Lukowiak et al., 2015;Rai and Fanai, 2016). ...
In this work the complexes Ln(β-dik)3L (where Ln= Nd+3 e Er+3, β-dik= 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Btfa) and L= 1,10-Phenanthroline (Phen) or 2,2’-Bipyridyl (Bipy)), were synthesized from the direct reaction of LnCl3 with β-diketone and the ligands. The purpose was to create new lanthanide complexes with perspectives of use in markers. After the syntheses, the complexes were characterized by Solubility Test, Scanning Electron Microscopy (SEM) and the thermal properties of compounds were studied using Thermogravimetry Analisys (TGA), Differential Scanning Calorimetry (DSC) and Determination of Melting/Decomposition Intervals. Based on the verified properties, the solubility test found that the complexes are not soluble in chloroform and water. The microscope images showed an excellent crystallization of the complexes. The complexes are stable up to 120°C, after this temperature they show a peak in the DSC referring to the fusion and the beginning of decomposition. The values of activation energy suggests the following decreasing order of stability: Er(Btfa)3Phen>Nd(Btfa)3Phen>Er(Btfa)3Bipy>Nd(Btfa)3Bipy.
... The use of various materials that can emit near-infrared and visible light in optical waveguides has been investigated; these materials include glass doped with lanthanide elements, such as Er, Eu, Y, Ce, and Nd [6][7][8][9][10][11][12][13]. Er 3+ -doped SiO 2 glasses have potential optical telecommunication applications given their capability to radiate and amplify optical signals over the 1.54 μm wavelength range. ...
In this study, we demonstrated two processes for the fabrication of thin films comprising ZnO nanocrystals dispersed in a SiO2 matrix doped with Er3+ ions (Er3+-doped SiO2/ZnO nanocomposites). The thin films can be applied as SiO2 glasses for optical waveguide materials working at the 1.54 μm band. In the first process, the conventional sol–gel method was utilized to generate homogeneous materials wherein ZnO nanoparticles formed after heat treatment. In the second process, SiO2 and ZnO sols were separately prepared before the fabrication of Er3+-doped nanocomposites. Different fabrication conditions, such as doping concentration and heat treatment temperature, and the optical properties of the corresponding prepared films were presented. The optical properties of the two material systems were compared to propose and discuss different excitation mechanisms via the interaction between intermediate ZnO nanocrystals and Er3+dopants.
... The use of various materials that can emit near-infrared and visible light in optical waveguides has been investigated; these materials include glass doped with lanthanide elements, such as Er, Eu, Y, Ce, and Nd [6][7][8][9][10][11][12][13]. Er 3+ -doped SiO 2 glasses have potential optical telecommunication applications given their capability to radiate and amplify optical signals over the 1.54 μm wavelength range. ...
Nano-composite silica-phosphate system (SiO2-P2O5) co-doped with Al2O3 as a host material and prepared by sol gel technique in two forms monolith and thin film using multilayer spin-coating method were activated by Er 3+ and Yb 3+ ions as in the formula; [SiO2:11P2O5:3Al2O3:(1.2)Er:(1.2, 1.8 and 3)Yb]. The prepared samples have been synthesized using tetra-ethyl-orthosilicate (TEOS) and triethyl-phosphate (TEP) as precursor sources of silica and phosphorus oxides. The microstructure and crystallinity of the prepared samples will be characterized by using x-ray diffraction (XRD) which, imply that the crystallite sizes of [SiO2:11P2O5:3Al2O3:(1.2)Er:(1.2)Yb] at 500℃ for both thin film and monolith forms of the prepared samples were found to be equal to 35 and 33 nm, respectively. The refractive index will be evaluated by measuring the normal transmission and specular reflection of the prepared samples. The photoluminescence properties have analyzed in the visible wavelength range between 500 and 800 nm as a function of sample composition.
Sol–gel is a handy, very flexible, and cheap method to fabricate, study, and apply innovative photonic structures. The possibility
of starting from molecular precursors and elementary building blocks permits to tailor structures at the molecular level and
to create new materials with enhanced performances. Of specific interest for the study of important physical effects as well
as for application in light management are confined structures on the nano-micro scale as photonic crystal and planar waveguides.
Activation by luminescent species and in particular by rare earth ions allows results in the integrated optics area covering
application in sensing, biomedical diagnostic, telecommunication, lightning, and photon management. The present review is
focused on some recent results obtained by the authors in Sol–gel photonics. The first part presents colloidal structures
including single nano-micro spheres and photonic crystal structures. The second part of the review deals with amorphous and
transparent glass–ceramic employed for the fabrication of confined structures in planar format. Some specific application
are also reported to highlight the role of sol gel photonics in the development of high performance optical sensors, waveguide
lasers, and nanostructured materials.
Nanoparticles of lithium lanthanum tetraphosphates doped with different concentration of Eu3+ ions were synthesized. The selected tetraphosphate was used to fabricate a transparent composite where nanocrystals were immobilized in a sol-gel-derived silica-hafnia amorphous film. The structural and spectroscopic properties of the systems were investigated by XRD analysis, Raman spectroscopy, and photoluminescence measurements. For all the samples with the Eu3+ ions concentration from 1 to 100 mol% the monoclinic structure with a space group C12/c1 was determined. The mean diameter of nanocrystals determined by Scherrer equation was in the range of 40-55 nm. The luminescence of 10%Eu3+:LiLa(PO3)(4) in silica-hafnia matrix indicated the immobilization of Eu3+ ions into a distorted environment. The dependence of both luminescence intensity and lifetime on the Eu3+ concentration demonstrated effective reduction of concentration quenching in the tetraphosphate nanopowders.
In this paper we describe a composite system based on polystyrene
colloidal nanoparticles assembled and embedded in an elastomeric matrix
(polymer colloidal crystal, PCC), in the specific we have designed a PCC
structure which displays an iridescent green color that can be
attributed to the photonic crystal effect. This effect has been
exploited to create a chemical sensor, in fact optical measurements have
evidenced that the composite structure presents a different optical
response as a function of the solvent applied on the surface. In
particular we have demonstrated that the PCC possess, for specific
solvents: (i) high sensitivity, (ii) fast response (less than 1s), and
(iii) reversibility of the signal change. Finally preliminary results on
the PCC have shown that this system can be also used as optical writing
substrate using a specific solvent as ink, moreover an erasing procedure
is also reported and discussed.
This review discusses strategies for the synthesis of three-dimensionally ordered macroporous (3DOM) solids (inverse opals) by colloidal crystal templating. Compositions of 3DOM structures include simple and ternary oxides, chalcogenides, non-metallic and metallic elements, hybrid organo-silicates, and polymers. A wide range of 3DOM synthesis techniques, including sol–gel chemistry, polymerization, salt-precipitation and chemical conversion, chemical vapor deposition, spray pyrolysis, ion spraying, laser spraying, nanocrystal deposition and sintering, oxide and salt reduction, electrodeposition, electroless deposition, fabrication from core-shell spheres, and patterning methods, as well as templating using inverse opal molds to produce new opal compositions are reviewed. Potential uses of 3DOM solids, including photonic crystal, optical, catalytic, and bioglass applications are briefly discussed.
X-ray photoelectron spectroscopy (XPS) has been used in the study of sol gel-derived Er3+-activated xHfO2–(100−x)SiO2 (x=10, 20, 30, 40, 50mol) planar waveguides. The analysis of Si 2p and O 1s core lines were related to the Hf/Si molar ratio to assess the role of hafnia in modifying the silica network. Increasing the HfO2 content brings about a change of the Si 2p and O 1s binding energy respect to those from pure silica. This trend is explained with a formation of hafnium silicate in the matrix with successive phase separation between HfO2 and SiO2 rich phases. XPS results show that hafnia is well dispersed in the silica matrix for molar concentration below 30%. Formation of pure HfO2 domains was detected at higher hafnia concentrations in agreement with previous spectroscopic analyses.
Yb3+:YAG nano-ceramics have been obtained by a low temperature/high pressure sintering process. Structural properties have been studied by X-ray diffraction (XRD). Grain sizes and R.M.S micro-strains have been calculated based on the XRD patterns by Rietveld analysis method. Emission spectra and decay curves have been recorded and analyzed. It has been observed that the decay time decreases with the increase of sintering pressure. Presence of Yb3+–Yb3+ pairs have been detected by cooperative emission spectroscopy.
Sintering of rare earth phosphates REPO 4 (RE = La, Ce or Y) was studied using dilatometry. The presence of a secondary rare earth metaphosphate phase RE(PO 3) 3 as sintering aid was investigated. It proved to accelerate the densification but it activated fast grain growth, which was very detrimental to the microstructural design of processed ceramics. A temperature of 1400–1450 • C was required to sinter pure LaPO 4 and CePO 4 ceramics with fine grains. Both compounds behave similar while YPO 4 did not densify even at 1500 • C. The influence of specific surface area of starting powders, temperature and holding time on the sintering rate and microstructures of dense REPO 4 materials is also reported.