Synthesis of Self-Assembled Randomly Oriented VO2 Nanowires on a Glass Substrate by a Spin Coating Method.

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).

Design and optimization of a high efficiency CdTe-FeSi2 based double-junction two-terminal tandem solar cell.

This article theoretically demonstrates an enormously efficient CdTe-FeSi2 based dual-junction tandem solar cell accompanied by slender semiconductor layers. The peak efficiency of the device has been ensured through the optimization of its various attributes of window, CdTe (bandgap 1.5 eV) top absorber, FeSi2 (bandgap 0.87 eV) bottom absorber and back surface layers. Additionally, the impacts of thickness, doping and the level of defects in different window, base and rear surface layers have been examined to observe how different layers affect the solar cell's performance. The optimized n-CdS/p-CdTe/p+-MoS2--n-CdS/p-FeSi2/p+-Cu2SnS3 dual-junction tandem solar device displays an efficiency of 43.9% with a voltage at no load, VOC of 1.928 V, current density under a closed circuit, JSC of 25.34 mA/cm2, and fill factor of 89.88%, respectively. These results disclose the high potential of the suggested solar cell based on CdTe and FeSi2 compounds.

Numerical evaluation and optimization of high sensitivity Cu2CdSnSe4 photodetector.

Copper cadmium tin selenide (Cu2CdSnSe4) based photodetector (PD) has been explored with the solar cell capacitance simulator (SCAPS-1D). Herein, cadmium sulfide (CdS) and molybdenum disulfide (MoS2) are used as a window and back surface field (BSF) layers, respectively. The physical attributes, such as width, carrier density and bulk defects have been adjusted to attain the optimal conditions. In an optimized environment, the performance parameters of the Cu2CdSnSe4 (CCTSe) PD e.g. open circuit voltage (VOC), short circuit current (JSC), responsivity, and detectivity are determined as 0.76 V, 45.57 mA/cm2, 0.72 A/W and 5.05 × 1014 Jones, respectively without a BSF layer. After insertion of the BSF layer, the performance of the CCTSe PD is significantly upgraded because of the production of high built-in potential which rises the magnitude of VOC from 0.76 V to 0.84 V. For this reason, the responsivity and detectivity of CCTSe PD are also grows with the value of 0.84 A/W and 2.32 × 1015 Jones, respectively that indicate its future potential.

Numerical Expedition on the Potential of AgBiS2-Based Thin Film Solar Cells Employing Different Carrier Transport Layers.

In this study, a photovoltaic (PV) device has been developed by using AgBiS2 as the key material. The simulation of the photovoltaic cell has been performed using the SCAPS-1D simulator to analyze the impact of each layer. The design incorporates three window layers, CdS, In2S3, and ZnSe, alongside six familiar compounds, AlSb, CuGaSe2 (CGS), CuS, MoS2, Sb2S3, and WSe2, as the back surface field (BSF) layers. These heterostructures aim to uncover the potential of AgBiS2 in the realm of photovoltaic technology. When AgBiS2 functions within a singular heterojunction, specifically in configurations such as n-CdS/p-AgBiS2, n-In2S3/p-AgBiS2, and n-ZnSe/p-AgBiS2, the resulting values for open-circuit voltage (V OC) and the short circuit current (J SC) are found to be ∼0.90 V and ∼32 mA/cm2, respectively, while the corresponding power conversion efficiencies (PCE) are 23.56%, 22.60%, and 23.62%, respectively. On the contrary, the incorporation of various BSF layers like AlSb, CGS, CuS, MoS2, Sb2S3, and WSe2 results in a substantial increase in V OC, leading to an enhancement in PCE. Among the AgBiS2 based different dual-heterostructures, the outstanding PCE of 30.04% with a V OC of 1.12 V is achieved by n-ZnSe/p-AgBiS2/p+-Sb2S3 device. In comparison, the n-ZnSe/p-AgBiS2/p+-CGS structure exhibits a similar PCE of 30.03% with a V OC of 1.12 V. Additionally, the n-ZnSe/p-AgBiS2/p+-MoS2 arrangement demonstrates a PCE of 29.95% and a V OC of 1.12 V. The effective band alignments observed at the interfaces of ZnSe/AgBiS2 and AgBiS2/MoS2, ZnSe/AgBiS2 and AgBiS2/CGS, as well as ZnSe/AgBiS2 and AgBiS2/Sb2S3 contribute to a substantial built-in potential, leading to an elevated V OC. As an alternative to ZnSe, the CdS window could offer similar performances, whereas In2S3 might provide a lower efficiency. The elaborate simulation findings highlight the substantial potential of AgBiS2 as an absorber, particularly when coupled with different windows and BSF layers. This opens avenues for experimental research focused on AgBiS2 in the era of photovoltaic cells.

Design and simulation of a high performance Ag3CuS2 jalpaite-based photodetector.

This work provides a comprehensive investigation by using simulations and performance analysis of a high performance and narrowband Ag3CuS2 photodetector (PD) that operates in the near-infrared (NIR) region and is built using WS2 and BaSi2 semiconductors. Across its operational wavelength range, a comprehensive assessment of the device's electrical and optical properties such as photocurrent, open-circuit voltage, quantum efficiency, responsivity and detectivity is methodically carried out. Furthermore, a thorough investigation has been conducted into the impact of many parameters, including width, carrier density and defects of various layers. Also, the intricate interactions between WS2/Ag3CuS2 and Ag3CuS2/BaSi2 interface properties of the photodetector are explored. The Ag3CuS2-based PD remarkably produces the best outcomes with an open-circuit voltage of 0.74 V, current of 43.79 mA/cm2, responsivity of 0.79 AW-1 and detectivity of 4.73 × 1014 Jones and over 90 % QE in the NIR range for the Ag3CuS2 PD. The results showcase this jalpaite material as a promising one in the field of PD.

Numerical studies on a ternary AgInTe2 chalcopyrite thin film solar cell.

This paper theoretically outlines a new n-AlSb/p-AgInTe2/p+-BaSi2 solar cell. The dominance of several factors such as depth, carrier density and defects of every layer on the photovoltaic (PV) outcome has been ascertained applying Solar Cell Capacitance Simulator (SCAPS)-1D computer-based simulator. The AgInTe2 (AIT) solar cell has been probed for finding the role of BaSi2 as a back surface field (BSF) layer. It is revealed that the device power conversion efficiency (PCE) increments from 30% to 34% owing to the use of BaSi2 semiconducting BSF with VOC = 0.90 V, JSC = 43.75 mA/cm2, FF = 86.42%, respectively. The rippling of the output parameters with respect to the change in series and shunt resistances has also been probed and demonstrated. All the findings reveal the prospect of n-AlSb/p-AIT/p+-BaSi2 dual-heterojunction thin film photovoltaic cell.

Synthesis of Transparent CuI Thin Films by a Facile Low-Cost High Pressure (HP)-PECVD Method at Room Temperature for the Application in Solar Cells.

Copper iodide (CuI) thin films were prepared on a glass substrate by a facile high pressure (HP)-PECVD method at room temperature. For this, CuI powder was dissolved in CH3 CN. The CuI vapor with plasma was investigated by Optical Emission Spectroscopic (OES) data for identifying the species in the plasma. The XRD study reveals the polycrystalline nature of the films. The SEM analyses indicate the homogeneity of the films. The EDS mapping confirms that the thin films mostly consisted of carbon followed by nitrogen, copper and iodine, respectively. The band gaps of CuI thin films were in the range of ~2.71-3.14 eV. The high transmittance and band gap engineering in HP-PECVD-synthesized CuI thin films indicates their potential use as window and hole transport layers in low cost solar cells.

Theoretical insights into a high-efficiency Sb2Se3-based dual-heterojunction solar cell.

Here, we manifest the design and simulation of an n-ZnSe/p-Sb2Se3/p + -AgInTe2 dual-heterojunction (DH) solar cell which exhibits a prominent efficiency. The performance of the solar cell has been assessed with reported experimental parameters using SCAPS-1D simulator by varying thickness, doping concentration and defect density in each layer. The proposed structure shows an efficiency of 38.6% with V OC = 0.860 V, J SC = 54.3 mA/cm2 and FF = 82.77%, respectively. Such a high efficiency close to Shockley-Queisser (SQ) limit of DH solar cell has been achieved as a result of the longer wavelength photon absorption in the p + -AgInTe2 back surface field (BSF) layer through a tail-states assisted (TSA) two-step photon upconversion phenomenon. These results indicate hopeful application of AgInTe2 as a bottom layer in Sb2Se3-based solar cell to enhance the cell performance in future.

Concurrent investigation of antimony chalcogenide (Sb2Se3 and Sb2S3)-based solar cells with a potential WS2 electron transport layer.

Antimony (Sb) chalcogenides such as antimony selenide (Sb2Se3) and antimony sulfide (Sb2S3) have distinct properties to be used as absorber semiconductors for harnessing solar energy including high absorption coefficient, tunable bandgap, low toxicity, phase stability. The potentiality of Sb2Se3 and Sb2S3 as absorber material in Al/FTO/Sb2Se3(or Sb2S3)/Au heterojunction solar cells (HJSCs) with 2D tungsten disulfide (WS2) electron transport layer (ETL) layer has been investigated numerically using SCAPS-1D solar simulator. A systematic investigation of the impact of physical properties of each active material of Sb2Se3, Sb2S3, and WS2 on photovoltaic parameters including layer thickness, carrier doping concentration, bulk defect density, interface defect density, carrier generation, and recombination. This study emphasizes the exploration of causes of low performance of actual devices and demonstrates the individual variation in the open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), power conversion efficiency (PCE) and quantum efficiency (QE). Thereby, highly potential heterostructures of Al/FTO/WS2/absorber (Sb2Se3 or Sb2S3)/Au proposed, in which, the PCE over 28.20 and 26.60% obtained with V OC of 850 and 1230 mV, J sc of 38.0 and 24.0 mA/cm2, and FF of 86.0 and 89.0% for Sb2Se3 and Sb2S3 absorber, respectively. These detailed findings revealed that the Sb-chalcogenide heterostructure with potential WS2 ETL can be used to realize the fabrication of feasible thin film solar cells and thus the design of high-efficiency high-current (HEHC) and high-efficiency high-voltage (HEHV) solar panels.

Stress-induced phase-alteration in solution processed indium selenide thin films during annealing.

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 ß-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 ß-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 ß-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.

Solution-Processed Synthesis of Copper Oxide (Cu x O) Thin Films for Efficient Photocatalytic Solar Water Splitting.

This article reports a solution-processed synthesis of copper oxide (Cu x O) to be used as a potential photocathode for solar hydrogen production in the solar water-splitting system. Cu x O thin films were synthesized through the reduction of copper iodide (CuI) thin films by sodium hydroxide (NaOH), which were deposited by the spin coating method from CuI solution in a polar aprotic solvent (acetonitrile). The phase and crystalline quality of the synthesized Cu x O thin films prepared at various annealing temperatures were investigated using various techniques. The X-ray diffraction and energy dispersive X-ray spectroscopy studies confirm the presence of Cu2O, CuO/Cu2O mixed phase, and pure CuO phase at annealing temperatures of 250, 300, and 350 °C, respectively. It is revealed from the experimental findings that the synthesized Cu x O thin films with an annealing temperature of 350 °C possess the highest crystallinity, smooth surface morphology, and higher carrier density. The highest photocurrent density of -19.12 mA/cm2 at -1 V versus RHE was achieved in the photoelectrochemical solar hydrogen production system with the use of the Cu x O photocathode annealed at a temperature of 350 °C. Therefore, it can be concluded that Cu x O synthesized by the spin coating method through the acetonitrile solvent route can be used as an efficient photocathode in the solar water-splitting system.

Electronic Structure of In3-x Se4 Electron Transport Layer for Chalcogenide/p-Si Heterojunction Solar Cells.

In this article, we perform density functional theory calculation to investigate the electronic and optical properties of newly reported In3-x Se4 compound using CAmbridge Serial Total Energy Package (CASTEP). Structural parameters obtained from the calculations agree well with the available experimental data, indicating their stability. In the band structure of In3-x Se4 (x = 0, 0.11, and, 0.22), the Fermi level (E F) crossed over several bands in the conduction bands, which is an indication of the n-type metal-like behavior of In3-x Se4 compounds. On the other hand, the band structure of In3-x Se4 (x = 1/3) exhibits semiconducting nature with a band gap of ∼0.2 eV. A strong hybridization among Se 4s, Se 4p and In 5s, In 5p orbitals for In3Se4 and that between Se 4p and In 5p orbitals were seen for ß-In2Se3 compound. The dispersion of In 5s, In 5p and Se 4s, Se 4p orbitals is responsible for the electrical conductivity of In3Se4 that is confirmed from DOS calculations as well. Moreover, the bonding natures of In3-x Se4 materials have been discussed based on the electronic charge density map. Electron-like Fermi surface in In3Se4 ensures the single-band nature of the compound. The efficiency of the In3-x Se4/p-Si heterojunction solar cells has been calculated by Solar Cell Capacitance Simulator (SCAPS)-1D software using experimental data of In3-x Se4 thin films. The effect of various physical parameters on the photovoltaic performance of In3-x Se4/p-Si solar cells has been investigated to obtain the highest efficiency of the solar cells. The optimized power conversion efficiency of the solar cell is found to be 22.63% with V OC = 0.703 V, J SC = 38.53 mA/cm2, and FF = 83.48%. These entire theoretical predictions indicate the promising applications of In3-x Se4 two-dimensional compound to harness solar energy in near future.

Nafion-Modified PEDOT:PSS as a Transparent Hole-Transporting Layer for High-Performance Crystalline-Si/Organic Heterojunction Solar Cells with Improved Light Soaking Stability.

We demonstrate the chemistry of amphiphilic perfluorosulfonic copolymer Nafion-coated conductive poly(3,4-ethyelenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and its effect on the photovoltaic performance of PEDOT:PSS/crystalline Si (c-Si) heterojunction solar cells. The highly hydrophilic sulfonate group of insulating, chemically stable Nafion interacts with PSS in PEDOT:PSS, which reduce the Coulombic interaction between PEDOT and PSS. The highly hydrophobic fluorocarbon backbone of Nafion favorably interacts with hydrophobic PEDOT of PEDOT:PSS. These factors give rise to the extension of π-conjugation of PEDOT chains. Silver paste used as a top grid electrode diffused into the Nafion layer and contacted with underneath Nafion-modified PEDOT:PSS layer. As a consequent, solution-processed Nafion-coated PEDOT:PSS/c-Si heterojunction solar cells exhibited a higher power conversion efficiency of 14.0% with better stability for light soaking rather than that of the pristine PEDOT:PSS/c-Si device by adjusting the layer thickness of Nafion. These findings originate from the chemical stability of hydrophobic fluorocarbon backbone of Nafion, diffusivity of silver paste into Nafion and contact with PEDOT:PSS, and Nafion as an antireflection layer.