Perovskite–silicon tandem photovoltaics are emerging as leading candidates for next-generation solar technology. Despite the availability of many wide-bandgap perovskite compositions, the optimal top-cell material and bandgap that simultaneously maximize power conversion efficiency, environmental stability, and other device-relevant optoelectronic properties remain poorly explored, particularly in tandem architectures. Here, we present a combined first-principles and drift–diffusion study on structural and opto-electronic variations in FAPb(I1-xBrx)3 and FA0.8Cs0.2Pb(I1-xBrx)3 based perovskite top cells, integrated with a silicon TOPCon bottom cell. The studied perovskites show a direct bandgap nature along the high symmetry point R. We show that A-site alloying with Cs and halide substitution with Br induce significant strain in the Pb–X–Pb framework, with bond angles deviating from the ideal cubic 180° to ~165°, and bond lengths shrinking from 3.22 Å (I–Pb) to 3.05 Å (Br–Pb). Interestingly these distortions directly influence charge transport by increasing the carrier effective mass from 0.173 me in FAPbI3 to 0.243 me in FAPb(I0.8Br0.2)3 and 0.258 me in FA0.8Cs0.2Pb(I1-xBrx)3 which have not been reported elsewhere. Apart from this, our study of moisture stability revealed that in CsFA based perovskite, water molecules preferentially reside at the centre of the metal–halide framework (hollow position), with the H atoms oriented toward the A-site cation at a distance of about 1.98 Å from the slab (3.7 Å from halide atom). This configuration exhibits a weak adsorption energy of −0.15eV, enabled by the low polarity of the mixed A-site cations, highlighting enhanced moisture stability. Finally Drift-diffusion simulation of our 2T silicon-perovskite tandem solar cell showed an efficiency of 32.10% and impressive Voc of 2.05V obtained through careful current matching, interface passivation and band alignment of carrier transport layers.

Future developments in perovskite solar cells (PSCs) focuses on lead-free versions because of their lower toxicity. However, lead-free PSCs' limited Power Conversion Efficiency (PCE) compared to their lead-based counterparts prevents them from being used more widely. This issue can be successfully resolved with the multi-absorber approach since it maximizes the use of the solar spectrum. Therefore, this article incorporates numerical modeling guided optimization of a lead free all inorganic ITO/ETL/CsSnI3/CsSnCl3/HTL dual absorbers-based heterojunction structure to improve the performance of Cesium Tin Iodide (CsSnI3) and Cesium Tin Chloride (CsSnCl3) based single absorber PSCs. The critical device's parameters, such as absorber layer and carrier transport layer thickness, defect density, temperature, doping concentration, series and shunt resistances are thoroughly optimized and evaluated using Solar cell capacitance simulator (SCAPS-1D). The proposed dual absorber composition produces a substantial enhancement in performance with PCE ( eta ) of 24%, Short Circuit Current ( Jsc ) of 28.5 mA/cm(2), Open Circuit Voltage ( V-oc ) of 0.96 V, and Field Factor (FF) of 85.87% at a device defect density of 10(15) cm(-3) outperforming the 12.96% and 9.66% of PCE attained with the reported CsSnI3 and CsSnCl3 single junction counterparts.

With the rapid global expansion of photovoltaic cell deployment, the end-of-life crystalline silicon (c-Si) modules are projected to reach similar to 78 million tons by 2050, creating both environmental risks and vast opportunity for resource circularity. This study develops and evaluates an integrated laboratory-scale recycling framework for end-of-life c-Si solar cells, putting silica upcycling within circular PV supply chain. The research addresses three core questions: how selective wet-chemical recycling can support material circularity, which environmental hotspots are most sensitive to the process chemistry, and whether value-added silica recovery can increase techno-economic feasibility. High-purity mesoporous silica was recovered as the primary product, alongside silver, alumina and hydrogen as co-products, while secondary waste streams were cautiously managed through gas capture and ammonium-salt treatment. Gate-to-gate life cycle assessment (LCA) and life cycle cost analysis (LCCA) for a functional unit of 1 kg recovered solar cells indicate relatively low climate impacts, with reagent consumption, thermal energy demand and ammonium-salt treatment identified as key environmental drivers. Avoided production of primary silica and alumina generated environmental credits across several major impact categories. Overall, the findings exhibit how process-integrated environmental management and value-added silica recovery can provide a futuristic entry-point for emerging PV recycling infrastructures.

In this work, cesium bismuth iodide (Cs₃Bi₂I₉) perovskite was synthesized via chemical method and at room temperature, it exhibits a hexagonal crystal structure with P63/mmc space group. The material possesses an optical band gap of ∼2.13 eV, which is indirect in nature. The electrochemical properties of Cs3Bi2I9 were studied in a three-electrode system, where a maximum specific capacitance (Csp) of ∼744 Fg-1 was obtained at 2 mVs-1 scan rate. Under visible light illumination (1 SUN), the specific capacitance of the material enhanced significantly to ∼1291 Fg-1, measured at the same scan rate. This enhancement demonstrates the excellent photo-induced charge storage capability of the material. A two-electrode symmetric device provides maximum energy density of 15.50 Wh/kg at current density of 1 Ag-1 and power density of 1223 W/kg at 3 Ag-1. The fabricated device has shown 76 % retention of initial capacitance after 5000 galvanostatic-charge-discharge (GCD) cycles. Ion intercalation at electrode-electrolyte interface, followed by diffusion within the bulk, is responsible for charge storage and it enhanced with visible light illumination. The occurrence of ion intercalation was further confirmed by the X-ray diffraction (XRD) and elemental analysis of the used electrode after 5000 GCD cycles. The optical band gap obtained from first-principles density functional theory (DFT) matched well with experimentally obtained optical band gap. In addition, quantum capacitance of ∼1597 Fg-1 has been obtained for Cs3Bi2I9, indicating its high charge storage capability. These findings confirm that the material may be employed for energy storage as well as energy conversion.

In the absence of conventional energy sources renewable energy is the only suitable option left. Multiple renewable energy sources like Hydroelectric Energy, Tidal Energy, Geothermal Energy, and Solar Electrical Energy are becoming popular every day. There are multiple reasons such as its availability in small to large sizes, predictability, easy installation, smooth maintenance process, drop in system installation cost, and mostly fast return on investment. With the increase in demand for solar photovoltaic panels, the demand for producing higher power output from less area is increasing rapidly. Hence with every breakthrough, the efficiency of the Photovoltaic Panel is increasing rapidly. With continuous development, the PV modules are developed in such a way that light can be absorbed from the front and rear on both sides. In the Bi-facial module, the direct sunlight gets absorbed from the front, and the albedo is also absorbed from the back to increase the power generation further. With the implementation of half-cut technology, the shading losses are minimized further. Rapid development is also being done on MPPT and Inverter to improve efficiency. Presently a generalized mathematical model for bifacial half-cut module is not published in any literature. In this paper, the research gap is covered by designing a Bifacial Half-cut PV Module along with an MPPT and also a bidirectional DC-DC Converter for charging and discharging of Battery Bank. Finally, we have integrated the system and also have simulated the designed system to check its stability. Such a model helps in analyzing and validating performance characteristics of commercially available bifacial modules and half-cut modules.

The urgent need for renewable energy solutions has made perovskite solar cells pivotal in combating climate change. Among lead-free alternatives, germanium-based perovskites, particularly CsGeI3 with a 1.6 eV bandgap, show great promise for single-junction solar cells. However, their full potential remains untapped due to significant open-circuit voltage (Voc) losses arising from non-radiative recombination and low fill factor (FF), which limit device efficiency. In this work, we present for the first time the simulation of a p-i-n solar cell with the structure ITO/NiOx/CsGeI3/Al2O3/PCBM/C60/Ag, introducing Al2O3 as a tunnel layer to optimize charge transport and suppress recombination at the perovskite/PCBM interface. An optimal 4 nm Al2O3 layer not only enhances electron tunnelling efficiency but also prevents holes from the perovskite layer from recombining with electrons at the ETL, thereby significantly increasing recombination resistance, as revealed by Nyquist plot analysis. These optimizations result in a notable Voc of 1.26 V and FF of 81%, boosting single-junction efficiency by 4%. Physics based understanding of this improvement have been discussed through Capacitance-Voltage (CV) and Impedance-Spectroscopy (IS) study. Furthermore, thickness optimization across the device enables the construction of a tandem cell, pairing the CsGeI3-based top cell with a Silicon H-I-T bottom cell in a 2T configuration. The tandem cell achieves a remarkable efficiency of 31.39%, with Voc of 1.97 V, Jsc of 19.40 mA/cm2, and FF of 82.17%. This study shows the transformative potential of Al2O3 tunnel layers in advancing high-performance lead-free perovskite-silicon tandem solar cells, offering a critical pathway for sustainable and efficient photovoltaic solutions.

This work introduces a novel design for high-performance semi-transparent perovskite solar cells (STPSC) using CsPbI(1-x)Br(2+x) as the absorber layer, tailored for building-integrated photovoltaic (BIPV) applications. Optimized bilayer ETLs (TiO2/WO3, SnO2/BaSnO3) and Cu-based HTLs, along with a MoOx/Au/MoOx transparent electrode, enabled efficient charge extraction, achieving a power conversion efficiency (PCE) of 10.40 %, average visible transparency (AVT) of 38.57 %, and a Light Utilization Efficiency (LUE) of 4.02, in the device structure FTO/TiO2/WO3/CsPbIBr2/CuSCN/MoOx/Au/MoOx which is a notable high value reported for STPSCs. Chromaticity coordinates calculated in the CIE 1931 XYZ colour space for the top devices were (0.41, 0.29) and (0.36, 0.28), closely matching the AM1.5G spectrum, ensuring excellent colour neutrality perfect for aesthetic integration into architectural applications. Capacitance-voltage (C-V) and capacitance-frequency (C-F) analyses highlighted minimized hysteresis and stable charge dynamics, positioning this STPSC design as a promising candidate for efficient, transparent, and visually neutral photovoltaic systems.

The world is progressively moving towards greener energy sources to meet the goal of net carbon neutrality by 2050, and an accelerated rate of deployment of photovoltaic modules is witnessed internationally. At the end of their life, photovoltaic modules must be recycled to promote sustainable development goals and to restrict the escalation of dangerous pollutants from spent modules. The silicon wafer can be recovered through destructive or non-destructive routes. If the monocrystalline Si wafers are retrieved via the non-destructive method, they can serve as a substrate for second-life solar cells after retexturization. An imminent challenge of wafer re-texturization requires attention to fabricate second-life solar cells. Due to the surface conditions of a junction-removed wafer, it is often challenging to texture the recovered wafer with a surface reflectance similar to that of a virgin wafer. The height of the pyramidal structure, generated due to the directional etching of silicon via potassium hydroxide solution, must be controlled to integrate such refurbished wafers into the traditional solar cell fabrication process. This work produces a Si wafer with resistivity similar to 1 ohm-cm, thickness similar to 127-130 mu m, and reflectivity similar to 13-14%. Repurposing the recovered silicon wafer could add tremendous economic value to the global economy, avoid the energy cost during manufacturing, starting from ingot production to solar-grade silicon wafer fabrication, and effectively reduce the energy-payback time of the photovoltaic sector, promoting resource efficiency.

This study explores the optimization of triple cation (CsFAMA) mixed halide (I, Br) perovskite solar cells through cation engineering and halide tuning via comprehensive simulations. Csx(FA0.88MA0.12)1-xPb(I1-yBry)3 is modeled as the absorber layer, achieving a tunable bandgap range of 1.58-1.74 eV. Considering the exceptional stability of triple-cation perovskites, the objective is to determine the optimal bandgap and the material properties for single-junction solar cell applications, ensuring their suitability for real-world industrial deployment in thin-film n-i-p solar cells. A thorough evaluation of various hole transport/selective layers (HTLs), including Spiro-OMeTAD, CuSCN, Cu2O, and NiOx, alongside electron transport/selective layers (ETLs), such as SnO2 and TiO2, is conducted. The exhaustive analysis transcended standard J-V characterization, incorporating C-V and I-S measurements to unravel the intricate device physics-a dimension often over looked in current research. The stand out device, utilizing TiO2 as the ETL and NiOx as the HTL, showcased an extraordinary power conversion efficiency (PCE) greater than 27% (under ideal operating conditions) and a PCE of more than 25% (under simulated outdoor condition) with a bandgap of 1.58 eV. These compelling findings highlight the tremendous potential of the meticulously optimized perovskite composition, pointing toward an era of high-efficiency, commercially viable solar cell technology.

With the rapid expansion of photovoltaic technology, managing photovoltaic-solid waste has become a growing challenge. This study presents an efficient process for recovering metals and silicon wafers from end-of-life solar cells, which has significant potential for generating auxiliary sources of revenue for the world economy and mitigating resource depletion risks along with environmental offsets. Following aluminium removal from the back of the solar cells utilizing hydrochloric acid, 99.997 % pure silver extraction was successfully done via chronoamperometric etching with an exceptionally low energy consumption of 0.012 kWh.kg-1, ensuring 98.31 % extraction and 96.75 % recovery efficiency. The passivation layers were removed by hot ortho-phosphoric acid. The p-n junction etching was performed independently, yielding an average recovery of 94.46 % for alkaline etching (5 N purity) and 94.25 % for acidic etching (6 N purity). The environmental impacts of the developed recycling process were evaluated via life cycle assessment. Structural characteristics of reclaimed materials were studied using XRD, EDX and ICP-OES. A cost analysis validated the commercial viability of the process. Significant environmental offset of ∼ 230.80-251.68 kg CO2 eq. for every 1.0 kg of end-of-life silicon solar cells can be achieved by reducing hazardous waste, reclaiming high-purity materials, and lowering energy demands, reinforcing the circular economy principles in PV recycling.

Perovskite solar cells (PSCs) have been proven to become a promising alternative in place of conventional photovoltaic (PV) technologies, all thanks to their high-power conversion efficiency (PCE). This study, focus towards a comprehensive theoretical analysis and optimization of a high-performance four-cation PSC using SCAPS-1D simulation. The device structure explored is FTO/ZnSe/RbCs (FAMA)PbI3/MoO3/Au here absorber layer thickness, defect density, & operational temperature, were systematically varied to identify the configuration that yields maximum efficiency. Simulation results reveal that enhancing absorber layer properties specifically by increasing the thickness and minimizing defect density significantly boosts PCE. The electronic characteristics of both the ETL and HTL were also found to critically impact overall device performance. Additionally, the influence of temperature on device efficiency was examined, showing a gradual decrease in performance as the temperature varied in steps 300K to 360K. The best performance was observed at 300K, where the optimized RbCsFAMA based PSC gave a peak PCE of 27.23%, a short-circuit current density (JSC) of 22.05mA/cm2, an open-circuit voltage (VOC) of 1.38V, and a fill factor (FF) of 89.18%. The ideal absorber parameters were determined to be a thickness of 600nm and a defect density of 1×1013cm-3. These findings highlight the significant potential of multi-cation perovskite compositions like RbCsFAMA in developing highly efficient and thermally stable next-generation solar cells.

Performance of silicon solar cells using pure and Cd-doped SnSe as back surface field (BSF) layers in p-type Si wafer and n + -Si emitter has been simulated. Replacing n + -Si emitter with metal oxides, namely Cadmium oxide (CdO) and Tin oxide (SnO 2 ), the improvement could be achieved in the solar cell parameters open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF) and efficiency (η). Moreover, deposition of these oxides can be done at much lower temperatures compared to diffused Si emitters diffused at high temperatures. Also, the doped Si emitters make use of poisonous gases like diborane and phosphine. In this work, a low thermal budget silicon solar cell with pure and Cd-doped SnSe BSF and metal oxide emitters has been prepared.

All inorganic Cesium lead bromide (CsPbBr3) planar perovskites have garnered enormous significance in photovoltaic applications owing to its outstanding stability against oxygen, heat and moisture. However, the power conversion efficiencies of the CsPbBr3 planar perovskites are quite low primarily due to the inferior range of light absorbance and interfacial charge recombination losses. This issue can be successfully resolved with a novel multi-absorber architecture approach which incorporates dual absorbers consisting of a lower band gap Lanthanum Nickel Manganese Oxide (La2NiMnO6 or LNMO) material along with the wider band gap CsPbBr3 material so that the light absorbance regime could be well extended for maximal utilization of the solar spectrum. Therefore, this article incorporates numerical modeling and guided optimization of all inorganic ITO/ETL/CsPbBr3/La2NiMnO6(LNMO)/HTL dual absorbers-based heterojunction structure to improvise the power conversion efficiency of CsPbBr3 based single absorber PSCs. The critical device's parameters, such as; absorber layer and carrier transport layer thickness, defect density, temperature, doping concentration, frequency response, capacitance effects, Mott-Schottky effects as well as series and shunt resistances are thoroughly optimized and evaluated using Solar Cell Capacitance Simulator (SCAPS-1D) simulator. The proposed dual absorber layer composition produces a substantial enhancement in performance with a peak power conversion efficiency (PCE) of 26.98 %, short circuit current (J(sc)) of 39.75 mA/cm(2), open circuit voltage (V-oc) of 0.85 V, and fill factor (FF) of 77.98 % at a device defect density of 1015 cm(-3) outperforming the 11 % of PCE attained with the experimentally reported CsPbBr3 single junction counterpart along with PSCs with various dual absorbers-based composition.

SummaryThe photon‐trapping nanostructures greatly contributes in minimizing the light reflectance losses occurring due to air–semiconductor refractive mismatch in photodetector devices. Here we have proposed a vertically oriented CdSe/CdS/ZnSe tri material‐based multiple core–shell nanopillar array structure to act as a light‐trapping efficient antenna for broadband photodetection applications. The nanopillar structure consist of diamond shaped nanotexturization over its three layer pillar interfaces. The proposed nanotexturization over the triple‐layered nanopillar structure would feature multiple scattering mechanisms for the trapped photons enhancing their optical path length along with the defect‐free confinement of the exciton pairs. The lattice compatibility of the CdS and ZnS shell layers forms a bridge between the lattice‐mismatched CdSe core and ZnSe shell leading towards the attainment of a reduced strain as well as high photochemical stability and photo quantum efficiency. As compared to the single‐layered CdSe/ZnSe nanotextured core–shell nanopillar structure the double‐layered nanotextured CdSe/CdS/ZnSe exhibits a high photoresponsivity of 0.425 A/W and external quantum efficiency of 0.98 is attained. The obtained results exhibit that the double‐shell layered‐based nanotextured nanopillar array structure would be a well‐competent alternative as compared to the planar counterpart for next‐generation photodetector applications.

This research explores numerical modeling and simulation studies of a lead-free perovskite solar cell employing (Cs2AgBi0.75Sb0.25Br6) as the absorber layer and utilizing single-walled carbon nanotubes (SWCNTs) in conjunction with metal oxides as the electron transport layer (ETL). Systematic investigation with six different carrier transport layers (both ETL and hole transport layer) along with comprehensive exploration of device physics, coupled with diverse optimization strategies concerning thickness, bandgap, and defect density (both interfacial and bulk), has been carried out. Our study reveals that the proposed configuration can achieve a remarkable device performance, approaching 29.06% efficiency with a current density of 35 mA/cm(2). This achievement stands in close proximity to the Shockley-Queisser limit. It has been observed that SWCNT, with a 1.4 eV bandgap, enables favorable band alignment, extracting charge carriers efficiently and yielding an impressive 1.102 V open-circuit voltage. This work is poised to catalyze further experimental research, providing valuable insights for advancing perovskite solar cell technology.

"Necessity is the mother of invention." The global imperative to transition from fossil fuels to renewable energy sources, driven by the pressing issue of climate change, highlights the significance of advancing solar energy technologies. While single junction solar cells have reached a peak efficiency of approximately 31 %, the pursuit of higher efficiency has led to the exploration of tandem solar cell architectures, including perovskite-silicon and all-perovskite configurations. However, the widespread use of lead in perovskite structures raises environmental and health concerns. In response to these challenges, this study proposes a novel approach by integrating a tin-based wide bandgap absorber layer with a silicon HIT solar cell (Heterojunction with Intrinsic Layer). The investigation consists of an extensive exploration of six different carrier transport layers (CTL) for the top perovskite layer, considering variations in thickness and defect density. A comprehensive analysis of charge carrier dynamics within the device is conducted to understand the role of defect density in influencing solar cell performance parameters. Simulation results show that the overall tandem device gives an encouraging PCE of 32.12 % in 2 T configuration due to its excellent high value of current density matching 17.63 mA/cm2 and open-circuit voltage of 2.19V. We sincerely hope that our work will open new avenues in the field of Solar Photovoltaics paving the way for future innovations.

In this work, doped and dopant-free carrier-selective passivating contacts have been incorporated in Interdigitated Back Contact solar cells. TCAD simulation study was done to check the performance of an IBC-SHJ (Silicon Hetero-Junction) and IBC-POLO (POLy-silicon on Oxide as seen in TOPCon) cell structures for both p and n-type wafers. The IBC-POLO structure was also repeated with HfO2 and ZrO2 over electron transport and hole transport layers, respectively. Simulation study was done by replacing the doped silicon layers with dopant-free Transition Metal Oxides (TMOs). NiO was used as a dopant-free hole-selective contact, whereas Nb2O5 was used a dopant-free electron-selective contact. The fabrication of these materials is non-hazardous and at low temperatures due to which they are preferable over the doped Si layers that require toxic gases like phosphine, diborane, etc. and may also require high temperatures. For example, poly-Si layer applied in IBC-POLO requires an annealing temperature of over 800 °C; similarly, the diffusion of Front Surface Field (FSF) layer in normal IBC cells also requires the same high temperature. Temperature variation was done on these structures to check the dependence of solar PV parameters of each IBC structure on different temperatures. Same variation was checked with minority carrier lifetime of the silicon wafer.

Motivation: With the increase in world population, fossil-fuel-based energy will last for the next few years. Therefore, there is a need to shift from fossil-fuel-based energy sources to renewable energy sources. Solar cells directly convert sunlight into electrical energy. But the high cost is one of the major challenges of power generation by solar cells. The cost of a solar cell depends on different parameters like material consumption, silver consumption, specific fabrication facility, etc. There are several ways to mitigate the cost of solar cell and module production. Material cost can be optimized by the thinning of wafer thickness, whereas optimization of grid parameters can reduce the silver consumption. On the other hand, one of the important cost reduction parameters is the fabrication cost. This chapter describes the fabrication technology of solar cells in detail. Various steps are involved in solar cell fabrication, such as texturing, emitter diffusion, PSG removal and edge isolation, ARC coating, metallization and screen printing, and testing. CZ/FZ wafer is used to fabricate the solar cell. After the saw damage removal, the surface of the wafers shows high optical reflectivity, which can be reduced by texturing the surfaces and followed by the ARC coating. The next step is to create the junction, which can be done by emitter diffusion, wherein the case of p-type c-Si substrate n-type top layer will be the emitter and vice versa. To disconnect the top and bottom surface of the solar cell electrically, edge isolation is done. After that, passivation is done to passivate the surface defects by depositing a thin dielectric layer. For electrical 2connections, metallization is done to make the contacts in the form of fingers and busbars. For front contact, silver (Ag), and for rear contact, aluminum (Al) is used, and it is done by screen printing followed by co-firing. One of the important issues to reduce the solar cell cost is to increase the solar cell efficiency by minimizing the power losses (electrical and optical power losses) in the front grid structure optimization in the solar cell.

Metal halide perovskites owing to their excellent bandgap tunabilityhave shown great promise in designing two-terminal tandem solar cellsto push the limitations of single-junction devices. However, the useof lead in perovskite absorber layers has raised several questionsin this field due to the inherent toxic nature of this element. Moreover,most of the wide-band-gap top absorber layers that are used are composedof mixed halides (mixture of iodine and bromine), leading to halidesegregation inside the device and affecting its long-term performance.In order to address these issues, the present work focuses on thesimulation of a lead-free, single-halide, all-perovskite two-terminaltandem solar cell with its physical understanding in great detail.A total of 4 different absorber layers and 10 different charge transportlayers have been evaluated for bringing out the best device performance.Since the band gap of the absorber layers plays a vital role in determiningthe efficiency of the overall device, this work also contains a briefsummary of the band gap tuning of the perovskite crystal via compositionalengineering. It has been observed that methylammonium germanium halide(MAGeI(3)), having a thickness of 930 nm, is used as a topabsorber layer when combined with FA(0.75)Cs(0.25)SnI(3), which is used as a bottom absorber layer havinga thickness of 507 nm; the best-performing tandem device has beenobtained with a current density matching of 16 mA/cm(2) anda PCE of 29.26%, thus showing a lot of potential for future investigations.