This study explored how a thin film of meso-tetra (4-carboxyphenyl) porphyrin (TCPP) affects the electrical and dielectric properties of an Au/n-Si Schottky diode. The structural and surface features of the deposited TCPP film on n-Si were examined using X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Fourier-transform infrared (FT-IR) spectroscopy verified the molecular structure and purity of the film. Temperature-dependent current density-voltage (J-V-T) measurements were conducted between 300 and 390 K in dark conditions to analyze the device's electrical performance. The junction showed strong rectification, with a high rectification ratio of approximately 71.97 at +/- 1. 5 V, indicating effective junction formation and low reverse leakage. Analyzing the J-V-T characteristics allowed for the extraction of key parameters such as the ideality factor, barrier height, and series resistance, offering insights into the main charge transport mechanisms during both forward and reverse bias. Under illumination, the device shows high photosensitivity, with more photocurrent and better photocarrier generation and separation. The study of AC conductivity dispersion indicated that charge transport in the Au/TCPP/n-Si/Al heterojunction follows the correlated barrier hopping (CBH) model, as evidenced by the temperature-dependent reduction in the frequency exponent. Additionally, the frequency-dependent dielectric response was examined through the analysis of complex permittivity and electric modulus, shedding light on polarization processes within the structure. To untangle interfacial carrier dynamics, impedance spectroscopy was employed, and the data were fitted with a suitable equivalent circuit model, allowing detailed evaluation of charge transfer and recombination at the interface. Overall, the findings confirm that the Au/TCPP/n-Si/Al heterojunction holds significant promise as a high-performance photodetector for next-generation electronic devices.

Bismuth vanadate (BiVO4) is an n-type semiconductor of bismuth-based oxide perovskite nature, characterized by a relatively low bandgap of (2.2-2.5) eV. This material is primarily explored in photoanodes, electrodes, and photocatalysis phenomena. Nanostructures, greater availability, and a stable nature of BiVO4 have been demonstrated significantly in recent studies. The surface morphology, structure, optical properties, and electrical properties are considered for the effect of the bismuth to vanadium ratio in the precursor solutions. A simple and time-efficient spin coating at a moderate speed was used to synthesize the thin films. In our study, a low Bi/V ratio results in a single layer of BiVO4; however, a higher Bi/V ratio exhibits a heterostructure of BiVO4 and Bi4V2O11 by a single spin coating.Further increasing the Bi/V ratio yields almost a single layer of Bi4V2O11. The open circuit voltage is increased from 0.39 V at the single-phase BiVO4 to nearly twofold, 0.63 V with BiVO4/ Bi4V2O11 heterostructure due to ferroelectric properties. Interestingly, the existence of BiVO4 on Bi4V2O11 promoted an additional voltage to the open circuit voltage, exhibiting a small remanent voltage.

This study investigates the fabrication of BiVO4 and BiVO4@g-C3N4 nanocomposite thin films via spin coating to examine the structural and optical changes induced by g-C3N4 incorporation. X-ray diffraction (XRD) confirmed the formation of monoclinic scheelite-phase BiVO4. The diffraction peaks corresponding to V2O5 were observed for the film prepared from bismuth vanadate oxide powder (BVO-1), whereas the V2O5 peak was not detected in the sample prepared from BiVO4@g-C3N4 (BVO-2). Scanning electron microscopy (SEM) revealed a distinct fiber-like morphology for BVO-1 and a porous structure for BVO-2. Energy-dispersive spectroscopy (EDS) confirmed the uniform distribution of Bi, V, and O in the film. The bandgap energies (Eg) were determined to be 2.21 eV for BVO-1 and 2.52 eV for BVO-2, respectively. These structural and optical enhancements have improved the visible-light absorption and charge separation, making the films as the promising candidates for photocatalytic applications, such as the degradation of organic dyes, antibiotics, and pollutants, as well as water splitting under visible light.

The first‐ever investigation on rudorffite/silicon‐based two‐terminal (2T) tandem solar cells is presented in this innovative study, which investigates their potential to achieve unprecedented levels of efficiency. Thus, the only way to improve conversion efficiency in rudorffite photovoltaic systems would be to use multijunction or tandem ideas. For three distinct rudorffite materials—Ag 3 BiI 6 (1.71 eV), Ag 2 BiI 5 (1.90 eV), and AgBiI 4 (1.87 eV)—a number of parameters, including absorber thickness, electron transport layer thickness, hole transport layer thickness, absorber defects, and interference defects, are optimized. For every rudorffite material, the optimization efforts produce outstanding results that led to a notable increase in efficiency. The efficiency of Ag 3 BiI 6 increases from 5.77% to a remarkable 15.26%. Similarly, there is a significant improvement in the efficiency of Ag 2 BiI 5 , with an increase from 4.10 to 10.59%. Finally, AgBiI 4 shows significant improvement, with efficiency increasing from 4.06 to 10.44%. The 2T double‐junction solar cell configuration is investigated by combining rudorffite top cells with silicon‐based bottom cells. According to the results, the efficiency of Ag 3 BiI 6 , Ag 2 BiI 5 , and AgBiI 4 tandem solar cells is 22.31, 18.63, and 18.89%, respectively, showing remarkable improvements over their single‐cell counterparts.

The recent development of wireless communication technology has increased the risk of electronic equipment malfunctions and information leaks. To address this issue, we developed and evaluated a lightweight and flexible electromagnetic shielding material that can be applied to wearable devices by combining carbon nanotubes and elastomer materials.

We explored the growth rate and morphological characteristics of graphene nanowalls (GNWs) on copper (Cu), stainless steel (SUS), quartz and silicon (Si) substrates by changing the growth time using microwave plasma-enhanced chemical vapor deposition (MWPCVD). Furthermore, we investigated the impact of catalytic and non-catalytic substrates on the growth features of GNWs. The properties of GNWs were characterized using scanning electron microscopy (SEM) and Raman spectroscopy. The growth of GNWs occurred just after supplying the precursor on the Cu substrate, but those on SUS, quartz and Si delayed about 5 min, 10 min and 15 min, respectively, due to the low catalytic activity of the substrate. Once the growth started, there was not much of a difference in the growth rate. The average growth rate was about 2 nm/s. The crystallinity of GNW was improved with increasing growth time. It was found that Cu is the best substrate to get high-quality GNWs, but MWPCVD is a suitable technique to obtain GNWs on a variety of substrates at relatively low temperatures.

This study investigates the photovoltaic performance of bismuth vanadate (BiVO4)/bismuth ferrite (BiFeOs) heterostructures. By varying the pre-annealing temperature of the BiVO4 layer, we have achieved the significant enhancement in the open-circuit voltage (Voc) with the spontaneous formation of the polarized Bi4V2O11 interfacial layer. X-ray diffraction analysis confirms a pure rhombohedral distorted perovskite structure for BiFeOs and a monoclinic crystallographic nature for BiVO4. SEM analysis exhibits a porous structure with small spherical grains in the BiVO4 layer, with the dense and smooth surface of the BiFeOs layer. The heterostructures observed in a red-shifted absorption edge are compared with the individual materials, which indicates an improved light absorption. Tauc plot analysis has yielded the direct bandgap values of 1.88 eV and 1.83 eV for the BiVO4 annealing temperatures at 150 and 500 degrees C, respectively. The overall power conversion efficiency (eta) has remained low at 0.003 % and 0.005 %, demonstrating the potential of interfacial engineering to optimize the photovoltaic properties of BiVO4/BiFeOs heterostructures.

Bismuth vanadate (BiVO4) has been used as the photoanode electrodes in ferroelectric solar cells owing to its unique combination of properties: a narrow bandgap among ferroelectrics, economic viability, negative conduction band edge, and remarkable stability. The present work explores the fabrication and characterization of BiVO4 thin films prepared via spin coating, with a specific focus on elucidating the influence of the annealing temperature (400-550 degrees C) on their structural, optical, and photovoltaic properties. From X-ray diffraction (XRD) analysis, it is observed that higher annealing temperatures have promoted the formation of larger grains, enhanced crystallinity, and induced a preferred crystal orientation characteristic of the monoclinic scheelite structure. Tauc plot analysis shows the dependence of the optical band gap on the annealing temperature for BiVO4 thin films. The band gap values have decreased slightly from 2.50 eV at 400 degrees C to 2.44 eV at 550 degrees C. This is indicated by the slightly narrowed bandgap, which influences the structure of the material or defect states at higher annealing temperatures. A narrower bandgap allows for the absorption of lower-energy light, potentially improving the light absorption efficiency of BiVO4 thin films in photoanode applications. The influence of annealing temperature on BiVO4 thin film solar cell performance was investigated further through the analysis of open-circuit voltage (Voc), short-circuit current (Isc) and power conversion efficiency.

The growing interest in high-efficiency solar energy technologies has driven research on multijunction solar cells to flourish over the last several years. This study sheds light on the optical, structural, and morphological aspects of the (CH3NH3)3Bi2I9 ((MA)3Bi2I9) film by fabricating and analyzing it experimentally. This thorough investigation lays the groundwork for more research into the film's possible uses in solar cell technology. We performed simulations to enhance the efficiency of two-terminal (2T) perovskite/perovskite double junction and perovskite/perovskite/c-Si triple-junction solar cells (TJSC) by using the MA3Bi2I9 material. The power conversion efficiency was greatly increased by using 2T triple-junction solar cells; the increase was around 116.59% from single junction (13.80-29.89%) and 31.91% from double junction (22.66-29.89%). As far as we know, this is the first investigation of the efficacy of MA3Bi2I9 as a top layer in multijunction tandem configurations. This revolutionary approach allows both academics and industry experts to produce cost-effective and efficient tandem solar cells, thereby enhancing earth-based solar energy development.

Ferroelectric materials have attracted attention as photovoltaic materials since the open circuit voltage larger than bandgap has been reported. Bismuth vanadate (BiVO4) is an n-type semiconductor with a moderate band gap of 2.4 eV of a monoclinic phase. This material has been mostly studied in photoanode and photocatalysis in recent years. Similarly, bismuth ferrite (BiFeO3) is a p-type semiconductor with band gap of 2.2 eV. Ferroelectric and ferromagnetic are the two unique properties of this material. Some promising properties like good stability, natural abundance, moderate band gap, and nontoxic nature of these materials in the oxide family enthusiastically widen door towards the solar cells sector. However, the low power conversion efficiency of these materials is looking for new methods, technology, and structures. The purpose of this paper is to improve the photovoltaic properties with employing BVO/BFO pn junction cell compared with conventional BVO or BFO single-layer cell. The highly increased photovoltaic properties are expected by the combination of two layers or multiple layers. Similarly, the multiferroic property of bismuth ferrite material widens its scope in optoelectronics and nanotechnology as well as puts forward many possibilities of combination with other suitable materials. We fabricated the heterostructure of these materials for photovoltaic analysis at relatively low temperatures. The structure, surface morphology, and optical, and photovoltaic properties are exploited in our study by spin coating. The open circuit voltage (Voc) and short circuit current (Isc) are almost increased by three folds in the P-N junction heterostructure compared with single-layer cells. The absorption range is widened BVO/BFO heterostructure but the absorption coefficient is slightly lowered for high energy radiation due to the interface layer. The formation of BVO, BFO, BFO/BVO heterostructure, and the crystallinity of the material are confirmed by the XRD analysis, FE-SEM, and EDS analysis.

Inorganic metal halide solar cells made from perovskite stand out for having outstanding efficiency, cheap cost, and simple production processes and recently have generated attention as a potential rival in photovoltaic technology. Particularly, lead-free Ca3AsBr3 inorganic materials have a lot of potential in the renewable industry due to their excellent qualities, including thermal, electric, optoelectronic, and elastic features. In this work, we thoroughly analyzed the stress-driven structural, mechanical, electrical, and optical properties of Ca3AsBr3 utilizing first-principles theory. The unstressed planar Ca3AsBr3 compound's bandgap results in 1.63 eV, confirming a direct bandgap. The bandgap within this compound could have changed by applying hydrostatic stress; consequently, a semiconductor-to-metallic transition transpired at 50 GPa. Simulated X-ray diffraction further demonstrated that it maintained its initial cubic form, even after external disruption. Additionally, it has been shown that an increase in compressive stress causes a change of the absorption spectra and the dielectric function with a red shift of photon energy at the lower energy region. Because of the material's mechanical durability and increased degree of ductility, demonstrated by its stress-triggered mechanical characteristics, the Ca3AsBr3 material may be suitable for solar energy applications. The mechanical and optoelectronic properties of Ca3AsBr3, which are pressure sensitive, could potentially be advantageous for future applications in optical devices and photovoltaic cell architecture.

In recent years, Ag3BiI6 materials have gained popularity because of their low cost, high element abundance, and environmental friendliness. For the first time, this study was to determine the best organic hole-transport layer (HTL) for FTO/(c+mp)TiO2/Ag3BiI6/HTLs/Au structure, among well-known options like Spiro-OMeTAD, PTAA, P3HT and PEDOT:PSS by integrating experimental and simulation techniques. A single-step spin-coating process was used on FTO substrates to deposit the first (c+mp) TiO2 layer, followed by the Ag3BiI6 layer. After depositing, the films were analyzed for structural properties, thickness, optical properties, and surface morphology by X-ray diffraction (XRD), Dektak, ultraviolet-visible (UV-vis), and scanning electron microscopy (SEM). Additionally, solar cell capacitance simulator in one dimension (SCAPS-1D) simulations have been used to study the effects of aligning band energies, current density voltage (J-V) characteristics, quantum efficiency (QE), capacitance frequency (C-f), as well as generation and recombination rates. This study revealed that the device architectures of the investigated device types were greatly influenced by several factors, such as the Ag3BiI6 thickness and total defect density, as well as the specific HTL employed in the device design. It was found that by meticulously optimizing the total defect density and thickness of the absorbing layer and HTLs, notable improvements in efficiency were achieved for Spiro-OMeTAD (8.49%), PTAA (7.27%), P3HT (7.62%), and PEDOT:PSS (6.97%). The optimized performance has nearly doubled the performance of the initial structure, leading to a significant improvement in the FTO/(c+mp)TiO2/Ag3BiI6/HTLs/Au configuration. The numerical simulations of Ag3BiI6 solar cells, in combination with experimental investigations have not yet been reported.

We conducted a simple solution-based method to fabricate Bi2S3 nanowire thin film solar cells by spin coating with varying sulfur-to-bismuth ratios. Spherical nanoparticles were observed in the thin film with low-concentration sulfur solution, with these nanoparticles gradually changing to nanorods. Finally, nanowires of Bi2S3 were observed in the thin film with a high sulfur concentration in solution. The band gap gradually decreased with the increase in sulfur concentration. The solar cell performance was significantly improved with the nanowire structure. During film fabrication, sulfur vacancy defects appeared primarily because of high annealing temperatures. These defects were somewhat reduced by the high concentration of sulfur in the solution, supported by the energy-dispersive x-ray spectroscopy (EDS) results. The elemental chemical composition of Bi2S3 material showed an increase in the sulfur-to-bismuth ratio, reaching saturation at almost 0.9. In this work, we systematically observed the effect on the optical properties, surface morphology, and photovoltaic properties by changing the concentration of sulfur in the precursor. The nanowire structure with a high concentration of sulfur in the solution is a promising way to improve the Bi2S3 thin film solar cell.

This study has explored the development of V2O5/BiVO4 nanowire thin films using a spin-coating method prepared using two distinct approaches: solution and powder processes. We have investigated the impact of these preparation methods on the physicochemical properties of V2O5/BiVO4 nanowire films. Various characterization techniques such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and optical spectroscopy have been employed to examine the crystal structure, surface morphology, and light absorption behavior of the films. V2O5/BiVO4 nanowire thin films were synthesized from a powder process, whereas conventional BiVO4 films were synthesized from a solution. The findings from this comparative analysis provide valuable insights into the influence of the precursor preparation methods on the physicochemical properties of V2O5/BiVO4 thin films.

MXene-based aerogel nanocomposites have significant attention as the promising supercapacitor electrode materials. This review highlights their potential by exploring the synergy between MXenes and aerogels. MXenes have good electrical conductivity and a high specific surface area due to their inherent characteristics. When combined with the high porosity and tunable pore structure of aerogels, these nanocomposites exhibit enhanced performance in supercapacitors. This review delivers the complete outline on the current advancements in MXene-based aerogel nanocomposites for supercapacitor applications. We delved into MXenes and their advantages as electrode materials. Also, explored various fabrication strategies, including hydrothermal synthesis, freeze drying, and templating methods. The discussion emphasizes the key factors influencing the aerogel morphology and pore structure, highlighting their impact on electrolyte accessibility and charge storage performance. Furthermore, the review analyzes the synergistic effects of these composite structures on critical parameters like specific capacitance, rate capability, and cycling stability. The challenges and future directions for the field are also discussed. By optimizing MXene-based aerogel nanocomposites, researchers can improve the electrochemical performance of the supercapacitors.

To date, the lead-free perovskite has shown remarkable progress in solar cell development owing to its outstanding properties. Here, we report on the structural, optical, and photovoltaic properties of methylammonium bismuth iodide ((CH3NH3)3Bi2I9, MBI) and cesium bismuth iodide (Cs3Bi2I9, CBI) hybrid perovskite solar cells (HPeSCs) fabricated using the hot immersion method (HIM) with changing the composition x, ((CH3NH3)1-xCsx)3Bi2I9; from x = 0 to x = 1.0. The compact MBI and CBI films were successfully fabricated on FTO glass substrates at x = 0 and x = 1, respectively. On the other hand, the CBI/MBI mixed structure with a rough surface was obtained in the range from x = 0.2 to x = 0.8. An incorporation of CBI in MBI showed improvement, especially in optical properties, indicating that the absorption region was extended toward a longer wavelength region with increasing x. Interestingly, the open-circuit voltage of the hybrid cell was higher than that of the MBI or CBI cell, whereas the short-circuit current was lower than that of the MBI or CBI cell. This work provides alternative ways to fabricate lead-free PeSCs using a simple and low-cost method in the future.

The potential of silicon-based anodes, with their high specific capacity and abundant reserves, has sparked significant interest as a potential alternative to commercialized graphite anodes, paving the way for a promising future for energy materials. However, there are major challenges in the use of silicon. There are two main challenges with applying Si anodes: huge volume variations during lithiation and delithiation processes, and unstable surface electrolyte interphase (SEI) films, which cause pulverization and low cycling efficiency. The silicon nanostructure is a solution for preventing damage caused by large volume variations. However, a simple nanoparticle structure cannot obtain cycle characteristics that are conducive to practical use. Due to the volume change, the adhesion among the silicon nanoparticles, the binder, and the conductive material, and the cycle characteristics deteriorate. In contrast, porous silicon nanowires, with their unique structure and properties, offer a potential solution to these challenges, demonstrating their superiority over other materials.In this study, we introduced a groundbreaking innovation: porous silicon nanowires. These nanowires, created using the pioneering metal-assisted chemical etching method, possess a significant surface area and conductive path. This original development holds vast potential for energy materials and lithium-ion technology, stirring curiosity and anticipation in the scientific community. Silver nanoparticles were fabricated on silicon wafers by electroless plating. The silicon wafer was then immersed in an HF + H2O2 solution. The porous silicon nanowires detached automatically from the silicon wafer. Composite films of porous silicon nanowires and carbon nanotubes were fabricated without a binder or conductive material. We characterized the film removed from water and dried using an FE-SEM (JSM-7001F) and an optical microscope (VHX-7000). By contrast, the porous silicon nanowire's mean pore diameter and surface area were used to determine its porosity. The Brunauer–Emmett–Teller (BET) method (BELSORP-MINIX) was used to determine the surface area. Constant current charge/discharge cycling was carried out in a glove box. Our FE-SEM analysis revealed that the porous silicon nanowires were 70 nm in diameter and 10 μm in length, with pores in the range from 1 nm to 10 nm. These experiments achieved 480 m2/g of a groundbreaking specific surface area of silicon. By combining these porous silicon nanowires with carbon nanotubes, we formed a negative electrode without the need for a binder, as they were naturally intertwined. Our study demonstrated that the reversible capacity showed significantly higher stability during the first 100 cycles and remained at 1,966 mAh g-1 after 100 cycles. In combination with the higher silicon doping concentration, the larger number of pores may provide more stability for lithiation/delithiation. Because the charge/discharge characteristics did not alter the film structure, we concluded that porous silicon nanowires hold promise as negative electrodes in practical applications. Acknowledgment This work was supported by JST GTEX Program (Grant Number JPMJGX23S8 and JPMJGX23S5, Japan)

Dye-sensitized solar cells (DSSCs) represent a burgeoning photovoltaic technology with significant commercial promise due to their unique attributes, including semi-transparency, cost-effectiveness in manufacturing, simple fabrication methodologies, and strong performance in low-light conditions. The principal challenge facing DSSCs pertains to enhancing their efficiency and stability to bolster their viability as a sustainable energy solution. This research explores the impact of varying dye loading durations on the performance of ZnO-based dye-sensitized solar cells, which are fabricated on the FTO substrate. The study encompasses the analysis of I-V characteristics under both dark and illumination conditions, involving four distinct cells. During the cell fabrication process, the electrochemical Deposition (EPD) technique are employed for metal oxide deposition onto the electrode. A critical post-deposition step involved the application of hot compression at 60 MPa and room temperature to ensure the formation of a uniform, crack-free layer. Notably, the four sample cells underwent different dye immersion durations-30 minutes, 1 hour, 2 hours, and 3 hours-as part of the fabrication process. Performance parameters under dark conditions were extracted using the principles of thermionic emission Theory. Additionally, series resistance and shunt resistance were calculated from the I-V data under illumination conditions utilizing the Lambert W function. Notably, the cell with a 1-hour dye-loading period demonstrated superior performance, achieving a 2.7% conversion efficiency, a short-circuit current density of 8.9 $\text{mA}/\text{cm}{}^{\text{2}}$ , an open-circuit voltage $(V_{oc})$ of 0.53 V, and a fill factor (F F) of 0.56. These findings hold significant promise in advancing the efficiency of DSSCs as a sustainable energy solution.

The depletion of fossil fuels and increasing demand for the sustainable energy storage have driven research toward agricultural biomass-based activated carbons as a promising alternative for supercapacitor electrodes. This review explores the perspective of biomass-based activated carbons, highlighting their advantages, such as renewability, low cost, and abundant availability. It also discusses the conversion process of agricultural waste into activated carbons, emphasizing the role of activation methods in tailoring the pore structure and surface chemistry for enhanced electrochemical performance. The key characteristics of activated carbons derived from various agricultural sources and their effects on the specific capacitance and energy/power density are compared and analyzed. Furthermore, this review has addressed the challenges of using agricultural biomass for activated carbon production, including process optimization and environmental considerations. Finally, this review summarizes the future outlook of this field, and current research efforts to develop high-performance, sustainable supercapacitors using agricultural biomass-derived activated carbons.

In the realm of solid-state lithium-ion battery (SLIB) research, anode development remains a focal area because the interface between the solid electrolyte and the anode plays a critical role in determining battery performance. Among various anode materials, vertically aligned graphene nanowalls (GNWs) stand out as a promising candidate due to their extensive surface area, sharp exposed edges, and high conductivity. These features give GNWs great potential to enhance the efficiency and capacity of solid-state batteries. However, the plasma generated in microwave plasma chemical vapor deposition (MWPCVD) equipment chamber exhibits uneven distribution, making it challenging to achieve uniform growth of GNWs over a large area. To improve the in-plane uniformity during the growth of GNWs, a drive motor was installed beneath the substrate holder, allowing the substrate to rotate at a constant speed during the film deposition process, thus enhancing the in-plane uniformity of the GNWs. This paper also showed that the charge-discharge properties of SLIBs are improved with substrate rotation. Compared with the previously reported method of producing uniform microwave plasma through rapid rotation and slow pulsation in a resonant field, this modification of the apparatus is simpler. Additionally, the use of a mixed gas can effectively improve the uniformity of the in-plane GNW films, providing a viable reference for the mass production of SLIB anode electrodes.