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Deep Learning for Optoelectronic Properties of Organic Semiconductors
摘要： Atomistic modeling of the optoelectronic properties of organic semiconductors (OSCs) requires a large number of excited-state electronic-structure calculations, a computationally daunting task for many OSC applications. In this work, we advocate the use of deep learning to address this challenge and demonstrate that state-of-the-art deep neural networks (DNNs) are capable of accurately predicting various electronic properties of an important class of OSCs, i.e., oligothiophenes (OTs), including their HOMO and LUMO energies, excited-state energies and associated transition dipole moments. Among the tested DNNs, SchNet shows the best performance for OTs of different sizes, achieving average prediction errors in the range of 20-80meV. We show that SchNet also consistently outperforms shallow feed-forward neural networks, especially in difficult cases with large molecules or limited training data. We further show that SchNet could predict the transition dipole moment accurately, a task previously known to be difficult for feed-forward neural networks, and we ascribe the relatively large errors in transition dipole prediction seen for some OT configurations to the charge-transfer character of their excited states. Finally, we demonstrate the effectiveness of SchNet by modeling the UV-Vis absorption spectra of OTs in dichloromethane and a good agreement is observed between the calculated and experimental spectra.
关键词： optoelectronic properties,organic semiconductors,transition dipole moment,SchNet,oligothiophenes,deep learning,UV-Vis absorption spectra
更新于2025-09-23 15:19:57
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Microwave-assisted particle size-controlled synthesis of ZnO nanoparticles and its application in fabrication of PLED device
摘要： ZnO nanoparticles were synthesised in diethylene glycol (DEG) with different ZnO molar precursor concentration (1 mmol, 2 mmol, 4 mmol and 8 mmol) in a microwave reactor for 15 minutes up to 250 °C. Zinc acetate dihydrate was used as the precursor for ZnO nanoparticles and oleic acid as a capping agent. It was found that different mmol precursor concentration yielded in different nanoparticle sizes. The crystallinity and particle size was analysed by XRD and the optical properties of the nanoparticles were studied by UV-Vis and PL. Oleic acid forms a layer around the ZnO nanoparticle surface. This layer helps in preparing nanocomposite solution by dispersing the ZnO nanoparticles in MEH-PPV solution. Further, the nanocomposite solution is deposited as a thin-film by spin-coating and this forms the emissive layer of the fabricated PLED device. The diode characteristics were analysed by studying the I-V and EL graphs.
关键词： PLED device,ZnO nanoparticles,MEH-PPV,microwave-assisted synthesis,optoelectronic properties
更新于2025-09-23 15:19:57
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Hybrid glass optical fibers-novel fiber materials for optoelectronic application
摘要： Hybrid glass optical fibers incorporated with optoelectronic materials and functionalities are highly anticipated for potential applications in optical communication, remote sensing, biomedicine, and nonlinear optics. However, the design and construction of hybrid glass fibers present significant challenges due to restrictions on the composition of fiber fabricated using conventional chemical vapor deposition (CVD) methods and the difficulty in maintaining the optoelectronic performance stably of fiber prepared by common rod-in-tube fiber-drawing technique. In this review, a versatile fiber-drawing approach which is called “melt-in-tube” (MIT) or “molten core” is presented to produce hybrid glass optical fibers. During the fiber-drawing process, the core is melted whereas the cladding is only just softened. The recent advances of the hybrid glass fibers including glass core-glass cladding fiber, crystal core-glass cladding fiber, and semiconductor core-glass cladding fiber are reported. In addition, the extensive applications of the hybrid glass fibers in the fields of fiber laser, fiber sensing, frequency conversion, photodetection and thermoelectric conversion are also discussed. These breakthroughs and advances in novel fiber materials and applications offer new opportunities for the research and development of optoelectronic devices.
关键词： optoelectronic properties,melt-in-tube or molten core method,hybrid glass fiber
更新于2025-09-23 15:19:57
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Firsta??principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of ?±a?? and ?2a??SrZrS3: Implications for Photovoltaic Applications
摘要： Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm?1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo‐generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo‐generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.
关键词： Solar cell,Optoelectronic properties,Density Functional Theory,chalcogenide perovskites,earth–abundant materials
更新于2025-09-23 15:19:57
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Zinc Oxo Clusters Improve the Optoelectronic Properties on Indium Phosphide Quantum Dots
摘要： This study explored the effect of zinc precursors on the optical properties of InP quantum dots (QDs) by controlling the reactivity of zinc carboxylates via a simple thermal treatment. The formation of zinc oxo clusters, Zn4O(oleate)6 and Zn7O2(oleate)10, during the thermal decomposition of zinc oleate was confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. By using the zinc oxo clusters as reaction precursors, high-quality InP QDs with high photoluminescence quantum yield (PLQY) and narrow full width at half maximum (FWHM) were synthesized. (Green QDs: PLQY=95%, FWHM=37 nm. Red QDs: PLQY=84%, FWHM=40 nm) The analysis results showed that the improved optoelectronic properties were achieved by two important functions of the zinc oxo clusters: 1) suppressing the rapid depletion of the highly reactive phosphorus source and inducing size uniformity of the In(Zn)P core, and 2) facilitating the formation of an oxidized buffer layer, which effectively controls defects. Likewise, the use of reactivity-controlled species is an effective strategy for the synthesis of well-designed QDs.
关键词： full width at half maximum,InP quantum dots,optoelectronic properties,photoluminescence quantum yield,zinc oxo clusters
更新于2025-09-23 15:19:57
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Nanoshell quantum dots: Quantum confinement beyond the exciton Bohr radius
摘要： Nanoshell quantum dots (QDs) represent a novel class of colloidal semiconductor nanocrystals (NCs), which supports tunable optoelectronic properties over the extended range of particle sizes. Traditionally, the ability to control the bandgap of colloidal semiconductor NCs is limited to small-size nanostructures, where photoinduced charges are confined by Coulomb interactions. A notorious drawback of such a restricted size range concerns the fact that assemblies of smaller nanoparticles tend to exhibit a greater density of interfacial and surface defects. This presents a potential problem for device applications of semiconductor NCs where the charge transport across nanoparticle films is important, as in the case of solar cells, field-effect transistors, and photoelectrochemical devices. The morphology of nanoshell QDs addresses this issue by enabling the quantum-confinement in the shell layer, where two-dimensional excitons can exist, regardless of the total particle size. Such a geometry exhibits one of the lowest surface-to-volume ratios among existing QD architectures and, therefore, could potentially lead to improved charge-transport and multi-exciton characteristics. The expected benefits of the nanoshell architecture were recently demonstrated by a number of reports on the CdSbulk/CdSe nanoshell model system, showing an improved photoconductivity of solids and increased lifetime of multi-exciton populations. Along these lines, this perspective will summarize the recent work on CdSbulk/CdSe nanoshell colloids and discuss the possibility of employing other nanoshell semiconductor combinations in light-harvesting and lasing applications.
关键词： Optoelectronic properties,Nanoshell quantum dots,CdSbulk/CdSe nanoshell,Colloidal semiconductor nanocrystals,Quantum confinement
更新于2025-09-23 15:19:57
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Inorganic halide double perovskites with optoelectronic properties modulated by sublattice mixing
摘要： All-inorganic halide double perovskites have emerged as a promising class of materials that are potentially more stable and less toxic than lead-containing hybrid organic-inorganic perovskite optoelectronic materials. In this work, 311 cesium chloride double perovskites (Cs2BB’Cl6) were selected from a set of 903 compounds as likely being stable based on a statistically learned tolerance factor (t) for perovskite stability. First-principles calculations on these 311 double perovskites were then performed to assess their stability and identify candidates with band gaps appropriate for optoelectronic applications. We predict that 261 of the 311 Cs2BB’Cl6 compounds are likely synthesizable based on a thermodynamic analysis of their decomposition to competing compounds (decomposition enthalpy < 0.05 eV/atom). Of these 261 likely synthesizable compounds, 47 contain no toxic elements and have direct or nearly direct (within 100 meV) band gaps between 1 and 3 eV as computed with hybrid density functional theory (HSE06). Within this set, we identify the triple alkali perovskites Cs2[Alk]+[TM]3+Cl6, where Alk is a group 1 alkali cation and TM is a transition metal cation, as a class of Cs2BB’Cl6 double perovskites with remarkable optical properties, including large and tunable exciton binding energies as computed by the GW-Bethe Salpeter Equation (GW-BSE) method. We attribute the unusual electronic structure of these compounds to the mixing of the Alk-Cl and TM-Cl sublattices, leading to materials with small band gaps, large exciton binding energies, and absorption spectra that are strongly influenced by the identity of the transition metal. The role of the double perovskite structure in enabling these unique properties is probed through analysis of the electronic structures and chemical bonding of these compounds as compared with other transition metal and alkali transition metal halides.
关键词： stability,sublattice mixing,band gaps,inorganic halide double perovskites,optoelectronic properties,excitons
更新于2025-09-23 15:19:57
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Characterization and NO2 gas sensing performance of CdO:In2O3 polycrystalline thin films prepared by spray pyrolysis technique
摘要： Polycrystalline CdO:In2O3 thin films for gas sensor applications were prepared on glass and silicon substrates by using one-step spray pyrolysis technique from the aqueous solution of CdCl2 and InCl3 at a substrate temperature of 300 °C. The structure, surface morphology, and the optoelectronic properties of prepared films were characterized respectively by means of X-ray diffraction (XRD), atomic force microscope and UV–visible spectroscopy. Based on the XRD results, the polycrystalline nature of CdO films has been confirmed, and In2O3 films were found to exhibit a preferred orientation along (222) diffracted plane. The grain size varies between 9.0 and 28.4 nm. The results of Hall effect measurement of CdO:In2O3 thin films confirms that all films were an n-type semiconductor. The electrical properties of prepared thin films and their sensitivity to nitrogen dioxide (NO2) gas are also studied. The influence of the operating temperature and In2O3 concentration on the NO2 response were investigated. It is found that all films are sensitive to NO2 gas, and the ideal operating temperature for the film contented 20 vol% of In2O3 was found to be 200 °C at a gas concentration of 25 ppm. The sensing mechanism of the CdO:In2O3 thin film is discussed and attributed to electron transfer between the sensing element and NO2 molecules.
关键词： NO2 gas sensor,Sensitivity,Optoelectronic properties,Structural,Morphology,Metal-oxide semiconductors
更新于2025-09-19 17:15:36
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Structure-dependent performance of single-walled carbon nanotube films in transparent and conductive applications
摘要： We investigate a complex relationship between structural parameters of single-walled carbon nanotubes (namely, mean length, diameter, and defectiveness) and optoelectrical properties (equivalent sheet resistance) of thin films composed of the nanotubes. We obtained a systematic dataset describing the influence of CO2 concentration and growth temperature. On the basis of the experimental results, we prove the high Raman peak ratio (IG/ID), length, and diameter of the nanotubes to decrease the equivalent sheet resistance of the nanotube-based film. The approach employed highlights the change in the nanotube growth mechanism at the temperature coinciding with the phase transition between α-Fe and γ-Fe catalyst phases. We believe this work to be of high interest for researchers working not only in the field of transparent and conductive films based on nanocarbons, but also for those who reveals the fundamentals of the nanotube growth mechanism.
关键词： aerosol CVD,nanotube growth mechanism,optoelectronic properties,transparent conductive films,single-walled carbon nanotubes
更新于2025-09-19 17:13:59
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Rational Design of Bay-Annulated Indigo (BAI)-Based Oligomers for Bulk Heterojunction Organic Solar Cells: A Density Functional Theory (DFT) Study
摘要： In this paper, we have designed a series of oligomers based on the donor?acceptor concept. Here, acceptor bay-annulated indigo (BAI) dye and donor N-methyl-4,5-diazacarbazole (DAC) are joined by a thiophene linkage. We have substituted the 5th and 5′th positions of the acceptor unit and the 2nd position of the donor unit with various electron-withdrawing and electron-donating groups to study various structural and electronic properties of the compounds. In this regard, we have calculated the dihedral angle, distortion energy, bond length alteration (BLA) parameters, bang gap (ΔH ? L) values, partial density of states (PDOS), electrostatic potential (ESP) surface analysis, reorganization energy, charge transfer rates, hopping mobility values, and absorption spectra of the compounds. The ESP plots of the compounds indicate signi?cant charge separation in the studied compounds. Our study manifests that the designed compounds are prone to facile charge transport.
关键词： charge transport,organic solar cells,donor-acceptor,density functional theory,optoelectronic properties
更新于2025-09-19 17:13:59