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In this article, AgGaTe2-based n-CdS/p-AgGaTe2/p+-SnS double-heterojunction solar cells have been designed and explored utilizing a solar cell capacitance simulator (SCAPS-1D). This design manifested n-type CdS and p+-type SnS as window and back surface field (BSF) layer, respectively with the AgGaTe2 absorber. The major contributing parameters of these layers such as thickness, doping concentration level, and bulk flaws have been adjusted to reach the optimum computation. This introduced n-CdS/p-AgGaTe2/p+-SnS double-heterostructure solar cell demonstrates the significant power conversion efficiency (PCE) of 32.48% with the open circuit voltage, VOC of 0.96 V, short circuit current, JSC of 38.64 mA/cm2, and the Fill factor, FF of 87.31%. This remarkable efficiency is originated by the formation of a higher built-in potential at the p-AgGaTe2/p+-SnS heterostructure and a decrease in the surface recombination velocity brought on by the SnS BSF layer. This computational study demonstrates the potential of AgGaTe2 as an absorber and SnS as a BSF layer, and pave the way for the AgGaTe2-based experimental research in the era of solar cells.

This article demonstrates the successful synthesis of indium selenide thin films by a spin coating method in air using thiol-amine cosolvents. The synthesized films encountered a transformation from β-In3Se2 to γ-In2Se3 phase due to mechanical stress during annealing as confirmed from XRD and EDS analysis. The SEM study ensured the homogeneity and uniformity of surface morphology of both phases. The FTIR analysis also confirmed the In–Se stretching vibration bond for both β-In3Se2 and γ-In2Se3 thin films. The temperature dependent electrical conductivity indicated the semiconducting nature of both phases. The optical transmittance was found to increase with annealing temperatures for both phases. The optical band gaps were estimated to be in the range of 2.60–2.75 and 2.12–2.28 eV for β-In3Se2 and γ-In2Se3 phases, respectively consistent with the reported values. These results indicate that stress-induced phase transformation in solution-processed indium selenide could be useful in 2D optoelectronic devices in future.

Randomly oriented vanadium dioxide (VO2) nanowires were produced on a glass substrate by spin coating from a cosolvent. SEM studies reveal that highly dense VO2 nanowires were grown at an annealing temperature of 400 °C. X-ray diffraction (XRD) provides evidence of the high crystallinity of the VO2 nanowires-embedded VO2 thin films on the glass substrate at 400 °C. Characterization by high-resolution transmission electron microscopy (HR-TEM) confirmed the formation of VO2 nanowires. The optical band gap of the nanowires-embedded VO2 thin films was also calculated from the transmittance data to be 2.65-2.70 eV. The growth mechanism of the solution-processed semiconducting VO2 nanowires was proposed based on both solvent selection and annealing temperature. Finally, the solar water splitting ability of the VO2 nanowires-embedded VO2 thin films was demonstrated in a photoelectrochemical cell (PEC).

Copper indium telluride (CuInTe2)-based n-CdS/p-CuInTe2/p + -MoS2 double-heterostructure solar cell has been investigated numerically by solar cell capacitance simulator (SCAPS-1D). Initially, an adjusted condition among the most influencing parameters e.g. thickness, carrier doping level, and bulk defects of active materials such as CdS window, CuInTe2 absorber, and p + -MoS2 back surface field (BSF) layers has been obtained by a systematic computation. The proposed solar cell exhibits an improved power conversion efficiency (PCE) of 34.32% with VOC =0.927 V, JSC = 42.50 mA/cm2, and FF = 87.14% under the optimized condition. The PCE can be further enhanced to 38.87% introducing sub-bandgap absorption in the MoS2 (300 nm) BSF with Urbach energy, E0 of 0.4 eV. These detailed simulation results reveal a huge potential of CuInTe2 absorber with MoS2 BSF layer for the manufacture of a cost-effective, high-efficiency double-heterojunction thin film solar cell.

In this work, a dual-heterojunction (DH) thin film solar cell of notable efficiency has been designed and simulated where p-type CuInSe2 (CIS) has been employed as the base layer in combination with an n-type CdS window and a p + -type GeSe back surface field (BSF) layer. The influences of each layer have been revealed using the SCAPS-1D simulator. While the n-CdS/p-CIS single heterojunction (SH) structure acting alone has been found to be resulted with 24.86% of photoconversion efficiency (PCE) with the JSC = 42.80 mA/cm2, VOC = 0.70 V, and FF = 83.44%, an enhancement to PCE of 30.52% is observed with the corresponding JSC of 44.10 mA/cm2, VOC of 0.86 V, and FF of 80.30% owing to the addition of GeSe as BSF layer in the proposed structure with optimized parameters. Because of the enormous built-in potential of the CIS/GeSe interface, increased VOC mostly contributes to the efficiency enhancement. These findings suggest that the CIS absorber layer with GeSe BSF layer is a promising choice for solar energy harvesting in the near future.

Here, we manifest the design and simulation of an

Randomly oriented vanadium dioxide (VO

In this article, we demonstrate the design and simulation of a highly-efficient n-CdS/p-CIGS/p+-CGS dual heterojunction solar cell. The simulation was performed using SCAPS-1D software with reported experimental physical parameters. The simulation performance of our proposed design arises 47% with Voc=0.98 V, Jsc=59.94 mA/cm2 and FF=80.07%, respectively. The high short circuit current and hence the high efficiency is predominantly originated from the longer wavelength absorption of photon through a tail-states-assisted two-step upconversion in dual heterojunction (DH) and thus reaches the SQ detailed balance limit of DH solar cell., Comment: 21 pages, 6 figures

This article reports the design and computational analysis of an efficient GeSe-based n-ZnSe/p-GeSe/p +-WSe2 dual-heterojunction (DH) thin film solar cell using SCAPS-1D simulation program with physical parameters from the literature. The device has been optimized considering the thickness, doping and defect density of each layer. The optimized device shows an efficiency of ∼42.18% with a short circuit current density, J SC of 47.84 mA cm−2, an open circuit voltage, V OC of 1.07 V and fill factor, FF of 82.80%, respectively that remains within the Shockley-Queisser limit of a DH solar cell. The raised built-in potential developed between the two interfaces of the devices produces a surpassing V OC. The higher J SC is attributed to the current generated by absorption of sub-band gap photons by a tail-states-assisted two-step photon upconversion mechanism in the WSe2 back surface field layer. These results indicate the potential of manufacturing the high efficiency GeSe-based DH solar cell in future.

In spite of having higher carrier mobilities and absorption coefficients of germanium (Ge) than those of silicon (Si), there has been less focus on Ge-based solar cells due to the low bandgap and high-cost of Ge wafer as well as requirement of its high-purity level. Currently, availability of high-purity Ge (HPGe), the low-cost wafer slicing method and proper design guidelines make it possible to design HPGe-based solar cells. Accordingly, in this article, we have designed and simulated a novel n-CdS/p-HPGe/p+-BaSi2 based npp+ double-heterojunction solar cell, where HPGe, cadmium sulfide (CdS) and orthorhombic barium disilicide (beta-BaSi2) have been used as the absorber, window and back-surface field (BSF) layers, respectively. Using the solar cell capacitance simulator (SCAPS-1D), the effects of different physical parameters such as the thickness, doping and defect densities, band offsets and temperature on the photovoltaic (PV) parameters of the designed solar cells have been investigated systematically. This article renders the optimized PV parameters to improve the device performance with the highest power conversion efficiency (PCE) of ~45.65% with a high open-circuit voltage of 1.16 V owing to the high built-in voltage of 1.7 V for the n-CdS/p-HPGe/p+-BaSi2 solar cells. This efficiency is almost consistent with the detailed-balance limit for double heterojunction solar cell., Comment: 23 pages, 9 figures

The effects of annealing and variation of temperature on the electrical and thermoelectric properties of e-beam evaporated InSe thin films has been investigated in details. The XRD study demonstrates that the as-deposited InSe thin films are amorphous while they become polycrystalline with the presence of In3Se4 phase after annealing. The SEM micrographs reveal that the surfaces of as-deposited films are smooth whereas they become non-uniform due to annealing. The heating and cooling cycles of the as-deposited films exhibit that the resistivity of the films shows an irreversible phase-transition and become stable after 3-4 successive heat-treatment operations in air. The electrical conductivity of annealed InSe thin films shows a highly degenerate semiconducting (metallic) behavior. The thermopower of the annealed films indicates that InSe thin film is a highly degenerate n-type semiconductor i.e. metallic. Thickness dependence thermopower obeys the Fuchs-Sondheimer theory. The optical band gap of the annealed films increases as compared to the as-deposited films. These results indicate that InSe thin films encounter a phase-transformation from In2Se3 to a new In3Se4 metallic phase with an optical band gap of ~1.8 eV due to heat-treatment., 25 pages, 16 figures

In this article, we perform a theoretical analysis on PEDOT:PSS/n-Si heterojunction solar cells for further enhancement of the solar cells. We introduced CdS and In3Se4 chalcogenide compounds as back surface field (BSF) layer in the solar cell. The impacts of various parameters such as the thickness, doping and defect densities on the photovoltaic performance have been investigated in details employing the solar cell capacitance simulator (SCAPS-1D) software. It is found that the power conversion efficiency (PCE) of the PEDOT:PSS/n-Si heterojunction solar cells significantly increases with use of these BSF layers. The optimized PCE of the PEDOT:PSS/n-Si solar cell is 22.46% which increases to 30.94% with VOC = 0.89 V, JSC = 44.02 mA/cm2 and FF = 78.92%, respectively due to the use of CdS BSF layer. On the other hand, the PCE of the solar cell is found to be 38% with VOC = 0.84 V, JSC = 53.22 mA/cm2 and FF = 85.11%, respectively as a result of longer wavelength absorption in In3Se4 BSF layer. These entire theoretical predictions indicate the promising applications of CdS and In3Se4 compounds as BSF layers in PEDOT:PSS/n-Si heterojunction solar cells to harness solar energy in near future.

Theoretical investigation of the elastic, electronic, superconducting, and thermal properties of newly synthesized cubic perovskite superconductor (Ba0.54K0.46)4Bi4O12 (BKBO) is carried out by generalized gradient approximation (GGA) which is based on density functional theory (DFT). Comparisons are made with two recently discovered Bi-basedAA'3B4O12-typeperovskite superconductors (Na0.25K0.45)Ba3Bi4O12 and (K1.00)(Ba1.00)3(Bi0.89Na0.11)4O12 and with available experimental data of (Ba0.54K0.46)4Bi4O12 perovskite. The elastic constants, mechanical stability, machinability index, Poisson's ratio, Cauchy's pressure, elastic anisotropy, Vickers hardness and Peierls stress are all investigated. The electronic band structure, density ofstates, features of Fermi surface and distributions of charge density are studied as well. Hybridization involving Bi-6s and O-2p orbitals (dominant contribution) is observed at EF similar to that seen in the previously published Bi-based perovskite superconductors. Both electron and hole like Fermi surfaces are seen which exhibits multiband nature of the superconductor. The flatness of the Fermi surface promotes transport features in Bi-based perovskite superconductor. The distribution of charge density of BKBO is basically spherical around all ions which essentially reveal the ionic characteristics of the material. The thermal properties, namely, Debye temperature, specific heat capacities and volume thermal expansion coefficient as a function of temperature areanalyzed with the help of quasi-harmonic Debye model. The estimated electron-phonon (e-ph) coupling constant of (Ba0.54K0.46)4Bi4O12 indicates its typical nature of a strongly coupled superconductor similar to the previously studied isostructural perovskites superconductors.

The effects of temperature and liquid-phase iodination on the electrical property of spin coated CuI thin films have been investigated in details. The XRD study indicates that CuI thin films are polycrystalline in nature and I-doping enhances the crystal quality and size of the films. The SEM images show that the surface uniformity of the CuI thin films increases due to I-doping. The doping of iodine increases the conductivity as well as carrier concentration and mobility of the films as confirmed by Hall study. The temperature dependent resistivity of CuI film shows a sharp fall of resistivity at ˜80 °C for un-doped films whereas this behavior disappears for I-doped films. The optical transmittance and band gap of the I-doped films also increases indicating high degeneracy of the films. These findings imply that I-doped spin coated CuI thin films are potential candidates for the solution-processed CuI/n-Si solar cells.