Suitability For Optoelectronic Applications Research Articles

Comprehensive study on pyrano[3,2-c]quinoline-based indole: Synthesis, characterization, and potential for optoelectronic and photovoltaic applications

The target indolylidenehydrazinylidenemethyl-pyrano[3,2-c]quinoline (IHMPQ) was synthesized and characterized. The DFT/ B3LYP approach using the 6–311++G(d,p) basis set was used to carry out the quantum computational calculations. The energy values of certain quantum chemical properties were calculated. The molecular electrostatic potential (MEP) and non-linear optical (NLO) characteristics are investigated. The Fukui function was used to forecast the reactive sites for electrophilic and nucleophilic attack using Mulliken population analysis. The calculated NMR chemical shifts were compared to experimental results. Furthermore, the study assessed the drug-likeness of the current compounds and discovered that they adhered to Lipinski's rule of five, making them appropriate for the development of oral drugs. Scanning electron microscopy was used to analyze the topography of the IHMPQ structure. The experimental results revealed a direct allowed energy gap, with values of 2.01 eV and 3.3 eV. Notably, IHMPQ films exhibit remarkable photoluminescence and absorption properties, suggesting their suitability for optoelectronic applications. Moreover, the investigation into the J-V characteristics of IHMPQ film-based devices under diverse illuminations unveiled a distinct response to incident light. This suggests the potential utility of these devices in solar cell applications.

First-principles study on electronic, mechanical, and optical properties of pressure-induced vanadium-based perovskite KVO3

Vanadium-based compounds exhibit a variety of excellent characteristics due to their variable oxidation states. In this study, Density Functional Theory (DFT) is performed to investigate the structural, electronic, mechanical, and optical properties of KVO3 under high pressure. The thermodynamical and mechanical stabilities under high pressure are probed by the negative value of formation enthalpy and Born-mechanical stability criteria, respectively. KVO3 displays a nearly metallic nature in both pressurized and unpressurized systems owing to its remarkably narrow band gap. Furthermore, a positive pressure coefficient of the band gap is revealed from electronic properties. A lower effective mass value for charge carriers indicates KVO3's suitability for optoelectronic applications. The mechanical properties indicate that increasing pressure results in a slight increase in elastic constants, elastic moduli, hardness, and machinability index. Additionally, it has been disclosed that it is capable of enduring localized plastic deformation and fracturing under intense pressure in a prospective application. The calculations of the complex dielectric function, absorption, reflectivity, conductivity, refractive index, and loss function for KVO3 with and without pressure reveal a substantial behavior change. The absorption edge exhibits a significant blue shift with the applied pressure. The high peaks in the UV region suggest that it can be used in UV detectors and anti-reflection coatings. The refractive index shows promising application in waveguides.

Optical properties of WTe2-a layered topological insulator: A DFT study

To assess its suitability for optoelectronic applications, the structural, electronic, and optical characteristics of a 2H type of layered WTe2 topological insulator have been examined using first principles DFT simulations. We have utilized single to four layers of two-dimensional 2H WTe2 for this purpose. An intriguing behavior has been uncovered in our studies. For 2H WTe2, monolayer to quad layer have distinct values for many optical characteristics such as the real and imaginary parts of the dielectric function, absorption coefficient, refractive index, etc. Our findings show that stacked 2H WTe2 might be useful in the production of optoelectronic devices.

Effect of Al doping on photoluminescence and conductivity of 1D CdS nanobelts synthesized by CVD for optoelectronic applications

One-dimensional Al-doped CdS nanobelts were synthesized for the first time via chemical vapor deposition. The vertically synthesized Cd 1- x Al x S nanobelts ( x = 0–3.09) exhibited high crystallinity. We have reported here an investigation of optical and electrical properties of prepared nanobelts for potential applications in nano-optoelectronics. The successful incorporation of Al into individual CdS nanobelts was confirmed by powder X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. Photoluminescence spectra showed multiple peaks; one emission band appeared at 728 nm (red emission), and a new broad emission band consisting of three peaks centered at 930–961 nm (NIR-1), 954–992 nm (NIR-2), and 1042 nm (NIR-3) appeared in the near-infrared (NIR). All the NIR peaks correspond to the d–d transition of Al ions. Doping with 3.09% Al increased the conductivity of the samples from 1.097 × 10 −6 to 2.59 × 10 −5 A, indicating suitability for optoelectronic applications, including nanoscale light sources and buffer layer materials in solar panels.

Tuning band gap and enhancing optical functions of AGeF3 (A = K, Rb) under pressure for improved optoelectronic applications

The current study diligently analyzes the physical characteristics of halide perovskites AGeF3 (A = K, Rb) under hydrostatic pressure using density functional theory. The goal of this research is to reduce the electronic band gap of AGeF3 (A = K, Rb) under pressure in order to improve the optical characteristics and assess the compounds’ suitability for optoelectronic applications. The structural parameters exhibit a high degree of precision, which correlates well with previously published work. In addition, the bond length and lattice parameters decrease significantly leading to a stronger interaction between atoms. The bonding between K(Rb)–F and Ge–F reveal ionic and covalent nature, respectively, and the bonds become stronger under pressure. The application of hydrostatic pressure demonstrates remarkable changes in the optical absorption and conductivity. The band gap becomes lower with the increment of pressure, resulting in better conductivity. The optical functions also predict that the studied materials might be used in a variety of optoelectronic devices operating in the visible and ultraviolet spectrum. Interestingly, the compounds become more suitable to be used in optoelectronic applications under pressure. Moreover, the external pressure has profound dominance on the mechanical behavior of the titled perovskites, which make them more ductile and anisotropic.

First Principles Study on Electronic and Optical Properties of Single Walled Carbon Nanotube for Photonics Application

Recent research works on single-walled carbon nanotube (SWCNT) based material has witnessed a great technological importance in photonic applications due to their unique optical characteristics. Present work aims to employ theoretical first principles study to explore the electronic and optical properties of SWCNT in the form of armchair nanotube. The theoretical simulation is done by using density functional theory (DFT) as implemented in the CASTEP computer code. Similar to almost gapless nature of graphene, formation of Fermi level of a relaxed SWCNT structure is found to be at a value approaching zero. The calculated electronic band structure shows a direct band gap of 0.259 eV with Dirac cone form between conduction and valence band. The optical spectrum shows a variation of real and imaginary of dielectric function with inter-band transition taking place along with frequency of the incident light. The absorption spectrum exhibits a significant degree of anisotropic characteristic with almost transparent nature ranging from near infrared to ultraviolet energy range. These optical spectra show excellent nonlinear optical features which remark the suitability in optoelectronic applications.

Graphene Oxide Concentration Effect on the Optoelectronic Properties of ZnO/GO Nanocomposites.

In this work, the effects of graphene oxide (GO) concentrations (1.5 wt.%, 2.5 wt.%, and 5 wt.%) on the structural, morphological, optical, and luminescence properties of zinc oxide nanorods (ZnO NRs)/GO nanocomposites, synthesized by a facile hydrothermal process, were investigated. X-ray diffraction (XRD) patterns of NRs revealed the hexagonal wurtzite structure for all composites with an average coherence length of about 40–60 nm. A scanning electron microscopy (SEM) study confirmed the presence of transparent and wrinkled, dense GO nanosheets among flower-like ZnO nanorods, depending on the GO amounts used in preparation. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis) absorption spectroscopy, and photoluminescence (PL) measurements revealed the impact of GO concentration on the optical and luminescence properties of ZnO NRs/GO nanocomposites. The energy band gap of the ZnO nanorods was independent of GO concentration. Photoluminescence spectra of nanocomposites showed a significant decrease in the intensities in the visible light range and red shifted suggesting a charge transfer process. The nanocomposites’ chromaticity coordinates for CIE 1931 color space were estimated to be (0.33, 0.34), close to pure white ones. The obtained results highlight the possibility of using these nanocomposites to achieve good performance and suitability for optoelectronic applications.

Plasma-assisted chemical vapor synthesis of indium tin oxide (ITO) nanopowder and hydrogen-sensing property of ITO thin film

Transparent conducting indium tin oxide (ITO) nanoparticles were synthesized by plasma-assisted chemical vapor synthesis route using indium nitrate and tin nitrate as the precursors. The injected precursors were vaporized in the plasma flame followed by vapor-phase reaction and subsequent quenching of the vaporized precursors produced nanosized ITO. The amount of tin nitrate was varied to obtain 5, 10 and 15 atomic percent Sn designated as ITO1, ITO2 and ITO3, respectively. The grain size of the produced ITO powder increased with increasing plasma torch power. On the other hand, it decreased with increasing plasma gas flow rate. The electrical and optical properties of ITO films prepared by spin-coating a dispersion of synthesized nanoparticles on a glass substrate vary as a function of tin content. Hall effect measurements showed that the minimum resistivity of 6.65 × 10−4 Ωcm was obtained for ITO2 film. ITO1 and ITO2 film exhibited an average transmission of 85% indicating their suitability in optoelectronic applications. The ITO gas sensor was exposed to different concentrations of H2 gas and temperatures to evaluate its gas sensitivity. The optimum operating temperature and gas concentration of H2 showing the highest sensitivity was determined to be 350 °C and 400 ppm, respectively. The linear relation between sensitivity and concentration up to 400 ppm of H2 can benefit the actuator to detect the concentration of H2 and thus making it suitable for high-performance hydrogen gas sensing applications.

Thioethyl‐Porphyrazine/Nanocarbon Hybrids for Photoinduced Electron Transfer

AbstractA novel pyrene‐substituted thioethyl‐porphyrazine (PzPy) and the formation of supramolecular assembly with nanocarbons demonstrating photoinduced electron transfer ability are designed. As revealed by spectroscopic and electrochemical studies, PzPy displays wide spectral absorption in the visible range, charge separation upon photoexcitation, as well as bandgap and highest occupied/lowest unoccupied molecular orbital (HOMO/LUMO) energy values, matching the key requirements of organic optoelectronic. Moreover, the presence of a pyrene moiety promotes attractive interactions with π‐conjugated systems. In particular, theoretical calculations show that in the PzPy the HOMO and LUMO are localized on different positions of the molecule, i.e., the HOMO on the pyrene moiety and the LUMO on the macrocycle. Therefore, HOMO–LUMO excitation gives rise to a charge separation, preventing excitons recombination. Two kinds of noncovalent hybrid composites are prepared by mixing the PzPy with single‐wall carbon nanotubes (SWNTs) and graphene nanoflakes (GNFs), respectively, and used for photocurrent generation through charge transfer processes between PzPy and nanocarbons. Photoconduction experiments show photocurrent generation upon visible light irradiation of both PzPy/SWNT and PzPy/GNF composites (0.78 and 0.71 mA W−1 at 500 nm, respectively), demonstrating their suitability for optoelectronic applications and light harvesting systems.

Synthesis, computational study and characterization of a 3-{[2,3-diphenylquinoxalin-6-yl]diazenyl}-4-hydroxy-2H-chromen-2- one azo dye for dye-sensitized solar cell applications

A solution-processable 3-{[2,3-diphenylquinoxalin-6-yl]diazenyl}-4-hydroxy-2H-chromen-2-one azo dye was synthesized. Analysis of measured UV-visible absorption spectrum and frontier orbitals computed using simplified time dependent density functional theory (sTDDFT) revealed its suitability for optoelectronic applications. A dye-sensitized solar cell (DSSC) was fabricated using this metal-free organic dye as a sensitizer. The photovoltaic parameters of the cell were studied under simulated AM 1.5 illumination (100 mWcm $$^{-2}$$ ). Comparing the photovoltaic data with a DSSC using a different member of the azo family of dyes, open circuit voltage and fill factor of the device studied in this work were found higher by 33 and 104%, respectively. The performance was also compared with the DSSCs fabricated using 49 commercial mordant dyes and open circuit photovoltage of the device studied in this work was found higher. To gain insight into its charge transport, impedance spectroscopy was performed. Impedance spectra were observed both voltage and frequency dependent.

Synthesis and characterization of zinc oxide thin films for optoelectronic applications.

Micro-ring structured zinc oxide (ZnO) thin films were prepared on glass substrates by spray pyrolysis and their structural, morphological, optical and electrical properties were investigated. X-ray Diffraction (XRD) analysis revealed the films’ hexagonal wurtzite phase with a preferred (002) grain orientation. The mean crystallite size calculated on the basis of the Debye-Scherrer model was 24 nm and a small dislocation density of was obtained, indicating the existence of few lattice defects and good crystallinity. Scanning Electron Microscopy (SEM) micrographs revealed the film’s granular nature composed of rod-shaped and spherical nanoparticles which agglomerated to form micro-ring like film clusters on the film surface. The average transmittance in the visible region, optical band gap and Urbach energy were approximately 75–80%, 3.28 eV and 57 meV, respectively. The refractive index and extinction coefficient were determined using Swanepoel’s envelope method. Raman spectroscopy revealed the presence of small amounts of residual tensile stress and low density of defects in the ZnO thin films. This was consistent with XRD analysis. A low sheet resistivity and high figure of merit were obtained for our films indicating their suitability in optoelectronic applications.

Systematic evaluation of a new organic material: 1-methyl-1H-imidazol-3-ium-2,4,6-trinitrobenzene-1,3-bis(olate) for optoelectronics through spectral, structural, electrical, optical, quantum chemical and Hirshfeld surface studies

A new organic material, 1-methyl-1H-imidazol-3-ium-2,4,6-trinitrobenzene-1,3-bis(olate) (MITB), was synthesized and crystallized by solution growth-slow evaporation technique at ambient temperature. The characteristic functional groups in MITB were identified from FT-IR spectrum. 1H, 13C and DEPT-135 NMR spectroscopic techniques were used to ascertain types of carbons and protons in MITB. The compound crystallizes in the monoclinic system with a space group of P21/c. The electrostatic attraction between anions and cations stabilizes the crystal lattice and the N-H…O and C-H…O hydrogen bonds linking the cations and anions supplement the stable three dimensional networks. The material was thermally stable up to 178 °C. The molecular structure was optimized by Gaussian 09 program at B3LYP/6–311++G(d,p) level of basis set. Hydrogen bonding interactions are responsible for greater hyperpolarizability value of MITB and the value was found to be 34 times greater than that of reference material, urea. HOMO-LUMO, electrostatic potential surface and Mulliken atomic charges were calculated to explore covalent and non covalent interactions present in MITB. Hirshfeld surface analysis was carried out to estimate prominent covalent and non covalent interactions. Dielectric constant and dielectric loss have been determined to find MITB's suitability for optoelectronic applications.

Directional solidification and characterization of InBi1−xSbx crystals

Homogeneous and stoichiometric samples of InBi1−xSbx (x = 0, 0.1) crystals have been directionally solidified to explore their suitability for optoelectronic applications. Prior to the growth, the temperature distribution of an indigenously fabricated horizontal furnace has been analysed and optimized to conduct the growth experiments on the basis of phase diagram of the material. Systematic trials have been carried out for several growth runs (48, 60 and 72 h) by maintaining an axial temperature gradient of 4, 6 and 8 °C/cm with the aid of a temperature controller mechanism. The key parameters governing the growth mechanism, composition, phase, and structure of the grown InBi1−xSbx crystals were investigated via X-ray diffraction, scanning electron and atomic force microscopy, Raman and Fourier transform infrared spectroscopy. The presence of secondary phases was ruled out and the average congruent melting points of InBi and InBi0.9Sb0.1 samples were confirmed as 109.43 and 121.13 °C respectively, by employing differential scanning calorimetric analysis. Investigations on the optical, electrical and mechanical properties of these materials were carried out. Vickers microhardness was found to increase with the Sb incorporation. The average optical band gap computed from the IR transmission spectra was found to be 0.165 eV. The results obtained promise that InBi1−xSbx crystals grown by directional solidification are favourable candidates than those grown by other melt methods.

Effect of gallium doping on the structural, optical and electrical properties of zinc oxide thin films prepared by spray pyrolysis

Gallium-doped zinc oxide (GZO) thin films were deposited onto glass substrates by the spray pyrolysis technique and the effect of gallium (Ga) doping on their structural, optical and electrical properties was investigated by X-ray Diffraction (XRD), Spectrophotometry and Current–Voltage (I–V) measurements, respectively. XRD studies revealed that all films were polycrystalline in nature, with a hexagonal wurtzite crystal structure and a predominant (002) c-axis orientation. Ga doping resulted in deterioration of the film's crystallinity, increase in full width at half maximum (FWHM) and reduction in the mean crystallite sizes. All GZO thin films had relatively higher average transmittances, approximately 70–85% in the visible region as compared to the undoped ZnO thin films. Introduction of Ga led to a blue shift in the optical band gap from 3.26eV to 3.30eV and an increase in the Urbach energy from around 67meV to 100meV. Ga doping induced a decrease in sheet resistance leading to a minimum electrical resistivity of 1.2Ωcm and a maximum figure of merit of 1.02×10−4Ω−1 for the 1at% GZO thin film, indicating its suitability for optoelectronic applications, especially transparent electrode fabrication.

Unraveling the Role of Π - Conjugation in Thiophene Oligomers for Optoelectronic Properties by DFT/TDDFT Approach

Thiophene oligomer has been investigated using DFT/TDDFT calculations with an aim to check its suitability for opto electronic applications and also to analyse the influence of π-bridge. Our results revealed that thiophene oligomers have excellent π-conjugation throughout. FMO analysis give an estimate of band gap of thiophene oligomer and further revealed HOMO are localized on π - bridge, donor group and LUMO are localized on π - bridge and acceptor group. A TDDFT calculation has been performed to understand the absorption properties of them in gas phase and solvent phase. PCM calculations convey that absorption maxima show positive solvatochromism. Among the designed candidates, the one with more π - bridge show higher wavelength of absorption maxima and would be a choice for better optoelectronic materials. NBO analysis provides support for complete delocalization in these systems. It is interesting to note that oligomer with more π-bridge display an enhanced optoelectronic properties than with less π - bridge.

Highly textured and transparent RF sputtered Eu2O3 doped ZnO films.

BackgroundZinc oxide (ZnO) is a wide, direct band gap II-VI oxide semiconductor. ZnO has large exciton binding energy at room temperature, and it is a good host material for obtaining visible and infrared emission of various rare-earth ions.MethodsEuropium oxide (Eu2O3) doped ZnO films are prepared on quartz substrate using radio frequency (RF) magnetron sputtering with doping concentrations 0, 0.5, 1, 3 and 5 wt%. The films are annealed in air at a temperature of 773 K for 2 hours. The annealed films are characterized using X-ray diffraction (XRD), micro-Raman spectroscopy, atomic force microscopy, ultraviolet (UV)-visible spectroscopy and photoluminescence (PL) spectroscopy.ResultsXRD patterns show that the films are highly c-axis oriented exhibiting hexagonalwurtzite structure of ZnO. Particle size calculations using Debye-Scherrer formula show that average crystalline size is in the range 15–22 nm showing the nanostructured nature of the films. The observation of low- and high-frequency E2 modes in the Raman spectra supports the hexagonal wurtzite structure of ZnO in the films. The surface morphology of the Eu2O3 doped films presents dense distribution of grains. The films show good transparency in the visible region. The band gaps of the films are evaluated using Tauc plot model. Optical constants such as refractive index, dielectric constant, loss factor, and so on are calculated using the transmittance data. The PL spectra show both UV and visible emissions.ConclusionHighly textured, transparent, luminescent Eu2O3 doped ZnO films have been synthesized using RF magnetron sputtering. The good optical and structural properties and intense luminescence in the ultraviolet and visible regions from the films suggest their suitability for optoelectronic applications.

Computational evaluation of optoelectronic and photophysical properties of unsymmetrical distyrylbiphenyls

Unsymmetrical distyrylbiphenyls (UDSBs) have been evaluated for their suitability for optoelectronic applications. Totally 14 UDSBs including four already reported have been investigated using DFT/TD-DFT calculations. The computed results reveal that the UDSB 1–12 can be used as good hole transport materials and UDSB 13 and 14 can be used as good electron transport materials. The newly designed UDSBs show promising optoelectronic properties and they can be used as a ‘trifunctional materials’ (emitter, hole and electron transport) in OLEDs. The results show that the HOMOs, LUMOs, energy gaps, ionization potentials, electron affinities, reorganization energies and exciton binding energies for these complexes are affected by different donor and acceptor groups. The photophysical characterization of the UDSBs show that, except UDSB 11–14 the absorption and emission spectra of all other molecules have π → π* character as revealed by natural transition orbital (NTO) analysis. The results obtained confirm that the optical properties of UDSBs can be significantly tuned by suitable substitution and these compounds can be used to make efficient OLEDs.

Structural and spectral characterization of novel non-centrosymmetric 2,4-dintrobenzene derivative

A novel organic compound 9-(2,4-dinitrophenyloxy)-3,3,8-trimethyl-1,5-dihydro-[1,3]dioxepino[5,6-c]pyridine (DNPAP) has been synthesized and a nonlinear optical (NLO) crystal has been grown by slow evaporation method. Compound was subjected to different characterization analyses in order to find out its suitability for optoelectronic applications. Single crystal and powder X-ray diffraction analyses show that DNPAP crystallizes in the orthorhombic space group Pca21. The range of optical absorption was ascertained by recording UV–Vis spectrum. The second harmonic generation (SHG) test has shown that DNPAP possesses 6.4-times higher NLO efficiency compared to KDP.

Application of Time-Dependent Density Functional Theory and Optical Spectroscopy toward the Rational Design of Novel 3,4,5-Triaryl-1-R-1,2-diphospholes

Twenty 3,4,5-triaryl-1-R-1,2-diphospholes were studied within the framework of density functional theory (DFT) and experimentally by UV/vis spectroscopy to check their suitability for opto-electronic applications. Time-dependent DFT (TD-DFT) calculations employing the PBE0 hybrid density functional combined with moderately sized def-TZVP basis set were shown to excellently reproduce the experimental absorption spectra of various 1,2-diphospholes. Frontier molecular orbital analysis reveals that HOMO and LUMO are mainly localized on the diphosphole ring and, to some extent, on the aryl moieties. The HOMO-LUMO energy gap can be easily tuned by variation of substituents introduced in para-positions of the aryl moieties and, to a lesser extent, by modification of the R group at phosphorus atom. As a result, both position and intensity of the absorption bands with highest wavelength are strongly influenced by the above structural changes. The UV-spectra simulations reveal that the introduction of donor groups like para-OMe, para-NMe2, and para-N(H)Ph, which are in n-π conjugation with the aryl moieties, should result in absorption of visible light by the corresponding 1,2-diphospholes, thus making them promising candidates for new functional materials.

Designing benzosiloles for better optoelectronic properties using DFT & TDDFT approaches

Like siloles, benzosiloles have low lying LUMOs due to σ*-π* conjugation between Si and the butadiene moiety but are more amenable for structural tuning. In total, 27 benzosiloles, 12 of them already synthesized and another 15 newly reported here, have been investigated using DFT and TDDFT calculations with an aim to check their suitability for optoelectronic applications. Our results show that all these molecules have excellent π-conjugation throughout. Frontier molecular orbital analysis gives an estimate of the band gap of these benzosilole derivatives and further reveals that the LUMOs are highly localized on the benzosilole moiety whereas HOMOs are localized on both the benzosilole moiety and the substituents. TDDFT calculations have been performed to understand the absorption properties in gas and solvent phases. PCM calculations show that solvation has a minimum effect on absorption maxima. Among the different functionals, PBE0 was found to perform well compared to other functionals and the computed absorption spectra are in good agreement with experiments. Among the designed candidates, styryl substituted benzosiloles are the most promising, showing higher wavelength of absorption and would make better OLED materials. NBO and AIM analysis provide evidence for complete delocalization in these systems. It is interesting to note that eleven out of the fifteen newly designed candidates have lower band gaps than the best known benzosilole derivatives synthesized so far.