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In this work, we delve into the investigation of the structural, electronic, and optical properties of Ba₂NbBiS₆ and Ba₂TaSbS₆ chalcogenide-based double perovskites, which are structured in the cubic space group $Fm\bar{3}m$ form. We have performed first-principles calculations using density functional theory (DFT) to study the above properties. The electronic band structure and density of states of this compound have been investigated, and their results show that Ba₂NbBiS₆ and Ba₂TaSbS₆ exhibit a semiconducting nature with an indirect energy gap of 1.680eV and 1.529eV, respectively. Furthermore, an investigation was conducted on the optical properties of the compounds throughout the energy range spanning from 0eV to 55eV. This investigation focused on many parameters, including dielectric functions, optical reflectivity, refractive index, extinction coefficient, optical conductivity, and electron energy loss. The optical data obtained from the calculations reveals that all compounds demonstrate isotropy in optical polarization. Furthermore, it has been noted that our compounds exhibit absorption properties inside the ultraviolet (UV) region. Consequently, these materials hold promise as potential candidates for various applications, such as UV photodetectors, UV light emitters, and power electronics. This is primarily attributed to their inherent absorption limits and the presence of prominent absorption peaks in this spectral range. In brief, chemical mutation techniques have been employed to manipulate the characteristics of double-sulfide perovskites to develop durable and environmentally friendly perovskite materials suitable for solar purposes.

Metal chalcogenide copper sulfide nanoparticles exhibit a broad spectrum of applications, encompassing solar cells, photovoltaics, optical devices, ionic materials and more. In this investigation, CuS nanoparticles were synthesized through a facile co-precipitation method. The synthesis involved employing copper sulfate and thiourea as precursors for Cu and S, respectively. Quantitative analysis, confirming the presence of Cu–S and S–S bonds, was conducted through Raman spectroscopy. X-ray diffraction (XRD) was employed to ascertain the structural phases. The semiconducting behavior of the synthesized CuS nanoparticles was studied through UV–Vis spectroscopy, correlating optical absorption and energy bandgap. The comprehensive findings suggest that the prepared CuS nanoparticles hold promise for advancements in photovoltaic technology and optical devices.

In this study, the composite P(4ClAni)/CuO, which consists of Poly(4-Chloroaniline) P(4ClAni) and copper oxide (CuO) nanoparticles, was successfully synthesized utilizing a chemically oxidative polymerization approach to be applied in optoelectronics. Both FTIR and EDX analyses showed that CuO has been successfully integrated into the P(4ClAni) matrix. The SEM micrographs reveal uniform loading and distribution of CuO throughout the P(4ClAni) polymeric chains. The UV–Vis absorbance, the Urbach energy, the band edge and a number of carbon clusters were determined. The Tauc relationship was used to determine the band gaps, which revealed a decrease as the CuO concentration increased. The band gap drops from 3.84eV for P(4ClAni) to 3.09, 2.85, and 2.64eV, correspondingly for P(4ClAni)/CuO-1, P(4ClAni)/CuO-2, and P(4ClAni)/CuO-3. While, the Urbach tail is increased from 1.66eV for P(4ClAni) correspondingly to 1.81, 1.85, and 1.93eV. The results show composites made of P(4ClAni)/CuO have better optical characteristics than pure polymer P(4ClAni), suggesting that they can use these composites in optoelectronics devices.

First principles investigation of PbTiO₃ in bulk and layer phases has been performed using full potential-linear augmented plane wave method (FP-LAPW) implemented in WIEN2K code, based on the density functional theory (DFT) within the generalized gradient approximation (GGA) to explore the structural, electronic, thermoelectric and optical properties of PbTiO₃. Total energy calculations, optimized structure, band structure, density-of-states (DoS), optical, and thermoelectric properties are computed and analyzed. The change in structural and electronic phases are observed. The optical properties of the compound can be studied by evaluating from the optical spectra and the changes in the properties such as complex dielectric function, absorption, energy loss function, refractive index and refractivity are studied. The thermoelectric properties are analyzed from Seebeck coefficient, power factor and thermoelectric figure of merit. The superior phase of PbTiO₃ is analyzed from the observation of all the above-mentioned properties for optoelectronic applications.

First principle calculations on cesium chloride (CsCl) compound have been performed using state of the art full potential linearized augmented plane wave (FP-LAPW) method. Calculated structural parameters are found in excellent agreement to the experimental results. Band gap of the compound decreases with the increase of pressure. At 507GPa, electronic nature of the compound changed from the insulating to metallic. Changes are reported in the optical properties like real and imaginary parts of dielectric function, optical conductivity and reflectivity of CsCl on application of high pressure.

p-type conductivity and the modulation of bandgap of ZnO are crucial aspects for realization of optoelectronic devices’ applications. The Li and Li-Cu could be suitable doping agents for achieving the p-type conductivity and the modulation of bandgap of ZnO. To this point of view, the Zn${}_{100-x}$Li${}_x$O (x = 0 to 40 at.%) and Zn${}_{100-x-y}$Li${}_x$Cu${}_y$O (fixed, x = 5 at.%, and y = 0.0 to 10 at.%) thin films were prepared on the microscopic glass substrates at a temperature of 350${}^{\circ }$C using cost effective chemical spray pyrolysis (CSP) technique. Field emission scanning electron microscope images show the coexistence of interconnected fibrous and flat grains on the films surface. The grain size changes as function of Li- and Li-Cu concentrations, and at a higher doping granular grains are observed. The successful incorporation of Li and Cu-Li into ZnO crystal is confirmed by X-ray photoelectron spectroscopy (XPS) measurements. The X-ray diffraction (XRD) patterns exhibit hexagonal polycrystalline structure of doped ZnO. However, the crystallinity is deteriorated at higher Li- and Li-Cu doping concentrations. The optical bandgap study exhibits direct transition type and it is red shifted from 3.21 to 2.61 eV and 2.84 to 3.56 eV for Li and Li-Cu doping in ZnO thin films, respectively. The optical conductivity enhances as a result of Li- and Li-Cu doping in ZnO. Therefore, Li- and Li-Cu can effectively be doped to tune bandgap and enhance optical properties of ZnO for electronic and optoelectronic device applications.

Flexible silver nanowires (AgNWs) transparent conductive films (TCFs) were fabricated on poly(ethylene terephthalate) (PET) substrate by using spray coating process. Effects of concentration and amount of AgNWs suspension on the performances of optoelectronics and microstructures of AgNWs TCFs were investigated. The experimental results demonstrate that as the increase of both of concentration and amount of AgNWs suspension, the sheet resistance and nonuniformity factor of the sheet resistance (NUF) and transmittance of AgNWs TCFs decrease and the root mean square (RMS) roughness and figure of merit (FoM) and haze of the AgNWs TCFs increase, respectively, due to the increase of the deposition density of AgNWs on the substrate. The flexible AgNWs TCFs with excellent comprehensive performance, which is a NUF of 0.48, haze of 1.94%, FoM of 148.5, transmittance of 84.5%, and sheet resistance of $12.95\mathrm{\Omega }\cdot {\mathrm{\text{sq}}}^{-1}$, can be obtained under the proper experimental conditions. The pressure treatment can improve the electrical conductivity of AgNWs TCFs due to the increase of contact area and the decrease of contact resistance. AgNWs TCF with pressure treatment also exhibits excellent reliability against mechanical bending over 1000 cycles. Our works demonstrate that flexible AgNWs TCFs with high performance can be obtained by using spray coating method, which is one of the common techniques for preparing coatings or films.

A finite discretization method in two dimensions has been developed and used to model electron transport in wurtzite phase GaN MESFETs. The model is based on the solutions of the highly-coupled nonlinear hydrodynamic partial differential equations. These solutions allow us to calculate the electron drift velocity and other device parameters as a function of the applied electric field. This model is able to describe inertia effects which play an increasing role in different fields of micro and optoelectronics where simplified charge transport models like drift-diffusion model and energy balance model are no longer applicable. Results of numerical simulations are shown for a two-dimensional GaN MESFET device which are in fair agreement with other theoretical or experimental methods.

This report reviews the feasibility of two-dimensional hydrodynamic models in bulk SiC and ZnO semiconductor materials. Although the single-gas hydrodynamic model is superior to the drift-diffusion or energy balance model, it is desirable to direct the efforts of future research in the direction of multi-valley hydrodynamic models. The hydrodynamic model is able to describe inertia effects which play an increasing role in different fields of micro and optoelectronics where simplified charge transport models like the drift-diffusion model and the energy balance model are no longer applicable. Results of extensive numerical simulations are shown for SiC and ZnO materials, which are in fair agreement with other theoretical or experimental methods.

In this paper, we have carried out a theoretical investigation on the structural and optoelectronic properties of NaCl under pressure effect via first principle calculations within the density functional theory. The structural phase transition from NaCl(B1) to CsCl(B2)-type structures is determined. The compound has a very wide bandgap in both phases. Optical properties including the absorption coefficient, optical conductivity and frequency dependent reflectivity are explained to characterize the optical nature of NaCl up to pressure of 134 GPa.

High speed random number generation (RNG) utilizing a nonlinear optoelectronic oscillator (OEO) is explored experimentally. It has been found that by simply adjusting either the injected optical power or the gain of the modulator driver, low complexity dynamics such as square wave, and more complex dynamics including fully developed chaos can be experimentally achieved. More importantly, physical RNG based on high-speed-oscilloscope measurements and pseudo RNG based on post-processing are implemented in this paper. The generated bit sequences pass all the standard statistical random tests, indicating that fast physical and pseudo RNG could be achieved based on the same OEO entropy source. Our results could provide further insight into the implementation of RNG based on chaotic optical systems.

We present the results of ab initio calculations of K-doped ZnO in the wurtzite structure using a supercell of 32 atoms and density functional theory. A complete analysis of its electronic, optical and magnetic properties is provided. The local spin density approximation (LSDA) has been used to analyze the density of states and to understand the K influence at different concentration values. The material is revealed to become a $p$-type doped semiconductor. The optical constant or refractive index, the dielectric function, and the absorption coefficient were determined and show a good agreement with available experimental data. Potassium doping leads to an absorption peak at about 380 nm. That peak might improve the absorption characteristics of ZnO for solar cell or optical applications.

In this work, we studied the electronic and optical properties of ${\mathrm{\text{Er}}}_x{\mathrm{\text{Ga}}}_{1-x}\mathrm{\text{N}}$ with a concentration $x=0.0625$. Based on a first-principle calculation and using the FP-LAPW full-linearized augmented plane wave method, to see the doping phenomenon with Erbium (Er) ${\mathrm{\text{4f}}}^{12}{\mathrm{\text{6s}}}^2$, we used the three approximations: local spin density approximation (LSDA), the LSDA$+U$ with $U$ is the Hubbard potential and the Becke–Johnson modification (mBJ). Our results show that the values of the structural parameters increase with the substitution of Ga by the Erbium atom. The analysis of the electronic structures in this study shows that the Er-doped GaN has a semi-metallic ferromagnetic character with the LSDA and mBJ approximations and a semiconductor behavior when we apply the Hubbard potential $U$. The real and imaginary part of the dielectric function, refractive index, and extinction coefficient are also calculated and presented in the photon energy range up to 14 eV. In the optical spectrum, the intensity of the absorption coefficient is observed in the imaginary part of both doped and undoped GaN in the ultraviolet regions.

Semiconductors are the backbone of the optoelectronic industry. Direct band gap materials in the visible energy region are highly desirable for the efficient optoelectronic applications. In this work, we have probed the structural, electronic and optical properties of Mg-IV-V₂ (IV$=$Si, Ge, Sn and V$=$P, As) compounds by FP-LAPW calculations, based on density functional theory. Their crystal structure is chalcopyrite with space group of I-42d. The lattice constants of MgSiP₂, MgSiAs₂ and MgGeAs₂ are consistent with experimental results. These compounds show semiconductor behavior with direct band gap ranging from 1.3–2.15eV. Optical properties were also investigated. Optical properties include real and imaginary parts of dielectric constant, energy loss function, refraction and reflection. Direct band gap nature and good response in the visible region of these compounds predict their usefulness in optoelectronic devices.

4-(4-dimethylaminostyryl)-1-methylpyridinium tosylate (DAST) is a very promising organic nonlinear optical (NLO) material for future optoelectronic and nonlinear optical applications, though it cannot be grown from molten state. Hence, a derivative of DAST was synthesized and mixed with DAST. The melting point of the mixed crystal decreased drastically, making it possible to grow a single crystal from molten state. In the present investigation, a mixed single crystal of DAST has been grown from molten state by vertical Bridgman–Stockbarger method.

In this study, the quantum state depression (QSD) in a semiconductor quantum well (QW) is investigated. The QSD emerges from the ridged geometry of the QW boundary. Ridges impose additional boundary conditions on the electron wave function, and some quantum states become forbidden. State density is reduced in all energy bands, including the conduction band (CB). Hence, electrons, rejected from the filled bands, must occupy quantum states in the empty bands due to the Pauli exclusion principle. Both the electron concentration in the CB and the Fermi energy increased, as in the case of donor doping. Since quantum state density is reduced, the ridged quantum well (RQW) exhibits quantum properties at widths approaching 200 nm. A wide RQW can be used to improve photon confinement in QW-based optoelectronic devices. Reduction in the state density increases the carrier mobility and makes the ballistic transport regime more pronounced in the semiconductor QW devices. Furthermore, the QSD doping does not introduce scattering centers and can be used for power electronics.

Iron-doped lead sulfide thin films were deposited on glass substrates using successive ionic layer adsorption and reaction method (SILAR) at room temperature. The X-ray diffraction pattern of the film shows a well formed crystalline thin film with face-centered cubic structure along the preferential orientation (1 1 1). The lattice constant is determined using Nelson Riley plots. Using X-ray broadening, the crystallite size is determined by Scherrer formula. Morphology of the thin film was studied using a scanning electron microscope. The optical properties of the film were investigated using a UV–vis spectrophotometer. We observed an increase in the optical band gap from 2.45 to 3.03eV after doping iron in the lead sulfide thin film. The cutoff wavelength lies in the visible region, and hence the grown thin films can be used for optoelectronic and sensor applications. The results from the photoluminescence study show the emission at 500–720nm. The vibrating sample magnetometer measurements confirmed that the lead sulfide thin film becomes weakly ferromagnetic material after doping with iron.

In the present work, nanocrystalline hausmannite Mn₃O₄:Ba thin films have been deposited on glass substrates by chemical spray pyrolysis (CSP). Then, we investigated the impact of Ba doping concentrations on the structural, morphological and optical properties. The structural characteristics were investigated by X-ray diffraction technique and clearly show the films have a spinel Mn₃O₄ polycrystalline structure, the degree of crystallinity was improved by increasing Ba concentrations in Mn₃O₄ matrix with crystallite size range of 15–33nm. The lattice parameters, the unit cell volume and the (Mn-O) bond length of tetrahedral and octahedral sites, were varied by increasing Ba concentrations. SEM micrographs show that the films are homogeneous with nanoparticles dispersed on the surface with sizes range 30–132nm. The optical properties were estimated by UV-Vis-NIR spectrophotometer and exhibited that the optical transmittance and band gap were improved by increasing Ba doping concentration. Empirical equations were suggested to estimate some correlated variables with excellent agreement with the experimental data. The optimum condition was recorded in films doped with 3% of Ba where a better crystallinity, a preferable surface morphology and outstanding optical properties have been achieved.

Poly-5,10,15,20-tetrakis($p$-aminophenyl)porphyrin films were obtained by interfacial polymerization and electropolymerization. According to the results of electron spectroscopy and IR spectroscopy it has been determined that oxidative polymerization of 5,10,15,20-tetrakis($p$-aminophenyl)porphyrin, regardless of its type (chemical/electrochemical), proceeds through the formation of phenazine and dihydrophenazine fragments. It has been established that the film obtained by the electrochemical method is in the oxidized state, the supporting electrolyte anions are included in the film. The polyporphyrin films obtained by interfacial polymerization are non-conductive. As a result of doping the films obtained by the chemical method, due to the oxidation in the anodic potential region, the polymer acquires $p$-type semiconductor properties. It has been shown that electrochemical doping of poly-5,10,15,20-tetrakis($p$-aminophenyl)porphyrin films can make them electroconductive. The obtained films can be recommended as elements of photovoltaic devices, the operation of which is based on the excitation of excitons under the action of light radiation, the redistribution of which leads to a change in the potential of the working electrode.

Ternary nickel cobaltite nanostructures have found their application in many optoelectronic devices due to their excellent electronic and catalytic properties. In this review paper, we will discuss two synthetic strategies for ternary nickel cobaltite nanostructures: nickel cobaltite nanopowders and conductive substrate supported nickel cobaltite, respectively. Then selected examples utilizing ternary nickel cobaltite nanostructures as building blocks for solar cells, photodetectors and water oxidation will be highlighted. In the end, an outlook and conclusion will be given about the future research and development in this field.