This study focuses on the simulation and optimization of an InGaP/GaAs dual-junction solar cells using Silvaco Atlas software, with a special emphasis on the incorporation of a hetero tunnel junction. The hetero-tunnel junction plays a pivotal role in enabling efficient charge carrier transport between the sub-cells, significantly improving the overall cell efficiency. Additionally, a new back-surface field (BSF) layer was integrated into the GaAs bottom sub-cell to further enhance performance. Various material combinations for the hetero-tunnel junction such as GaInP/GaAs, AlGaInP/GaInP, and AlGaInP/GaAs were systematically tested to assess their influence on device efficiency. The optimized structure demonstrated a short-circuit current density of 1.780 mA/cm², an open-circuit voltage of 2.310 V, a fill factor of 86.501%, and a conversion efficiency of 35.57% under AM1.5G illumination at 300 K. Recombination losses were minimized by the BSF layer optimization in the top and bottom cell, particularly with AlGaInP, leading to improved charge collection. Elevated temperatures were found to reduce both the open-circuit voltage and efficiency, highlighting the necessity of thermal management. These optimizations represent significant improvements over prior designs.

This study numerically optimizes Cu₂ZnSnS₄ (CZTS)/Cu(In,Ga)Se₂ (CIGS) tandem solar cells (TSCs) with a ZnS buffer layer using Silvaco-Atlas software, achieving a record simulated efficiency of 29.41% (AM1.5 G), a 4.14% improvement over the baseline (25.27%). Critical loss mechanisms are addressed through systematic parameter optimization: a CZTS absorber thickness of 0.18 μm balances photon absorption and transmission, while a doping density of 3 × 10¹⁶ cm⁻³ minimizes recombination losses by optimizing the depletion width. Comprehensive loss analysis reveals that excessive CZTS thickness (>0.18 μm) obstructs low-energy photons from reaching the CIGS subcell, while overdoping (> 3 × 10¹⁶ cm⁻³) narrows the depletion region, elevating recombination. Temperature-dependent simulations (260–380 K) demonstrate a 12.83% efficiency decline at 380 K, driven by bandgap narrowing (Varshni’s Effect) and increased recombination. This work resolves critical challenges in optical losses and thermal instability, providing a roadmap for eco-friendly, high-efficiency tandem photovoltaics.

Journal of Nano- and Electronic Physics. Scientific journal. ISSN: 2077-6772. Journal abbreviation: J. Nano- Electron. Phys. No page charges. All articles are freely available on-line. Issued 4 times per year. Publisher: Sumy State University. (Sumy, Ukraine)

This study explores the development of a lead-free CsSnI₃-based solar cell structure aimed at enhancing charge stability, transport, and overall performance. A device configuration of Spiro-OMeTAD/CsSnI₃/CH₃NH₃SnI₃/PCBM/ITO was simulated using the SCAPS-1D program. Simulation results, performed under standard illumination conditions (1000 W m⁻²) at 300 K, identified an optimal CsSnI₃ absorber layer thickness of 300 nm, corresponding to a defect density ranging between 10¹² cm⁻³and 10¹⁴ cm⁻³. This optimized configuration not only enhances device performance but also reduces the long-term environmental toxicity associated with tin. Through a detailed analysis of parasitic resistances, the optimal shunt resistance ( R shunt ) was found to be 10⁶ Ω.cm², with a series resistance ( R Series ) approaching zero. Under these conditions, the device achieved a fill factor ( FF ) of 71.99%, power conversion efficiency ( η ) of 19.47%, short-circuit current density ( J SC ) of 31.092 mA cm⁻², and open-circuit voltage ( V OC ) of 0.87 V. After optimizing the doping density, the performance was further enhanced, yielding V OC = 0.9919 V, J SC = 32.5664 mA cm⁻², FF = 71.64%, and η = 23.14%. These results closely align with the experimental findings reported by NREL in 2024. This work demonstrates significant advancements in the development of high-efficiency, environmentally friendly, lead-free CsSnI₃ solar cells, providing valuable insights for future research and practical applications.