Next-Generation Lead-Free Solar Cells with MASnBr₃/ZnSnN₂ Dual Absorbers for High Efficiency

Md. Mehedi Hasan¹Mst. Aysha Siddika²Md. Feroz Ali^3*Md. Rafiqul Islam Sheikh¹Abdullah Al Mamun⁴Md Jakir Hossen^5*

• ¹Rajshahi University of Engineering and Technology, Rajshahi, Bangladesh
• ²Pundra University of Science and Technology, Bogura, Bangladesh
• ³Pabna University of Science & Technology, Pabna, Bangladesh
• ⁴Griffith University, Brisbane, Australia
• ⁵Multimedia University, Malacca, Malaysia

This study presents a next-generation lead-free perovskite solar cell (PVSC) architecture employing a dual-absorber design using MASnBr₃ and ZnSnN₂ to enhance photovoltaic performance while ensuring environmental sustainability. The proposed structure-FTO/n-ZnO/p-MASnBr₃/p-+ ZnSnN₂/p-++ CNTS/Au-was simulated and optimized using SCAPS-1D software. Extensive material and structural optimization was conducted, including selection of electron and hole transport layers as well as tuning absorber thickness, doping concentration, and defect density. The dual-absorber configuration leverages the complementary optical properties of MASnBr₃ (bandgap: 1.3 eV) and ZnSnN₂ (bandgap: 1.5 eV), enhancing spectral absorption and carrier separation. Optimization of interface properties, series/shunt resistance, and operating temperature further improved the device's efficiency and stability. The final optimized structure achieved a power conversion efficiency (PCE) of 35.87%, with open-circuit voltage (VOC) of 1.17 V, short-circuit current density (JSC) of 34.39 mA/cm², and fill factor (FF) of 89.01%.Quantum efficiency analysis confirmed near-unity photon-to-charge conversion across the visible spectrum. This work demonstrates the viability of combining lead-free perovskites with nitride absorbers for high-efficiency, eco-friendly solar technologies and provides a scalable pathway for future experimental validation and commercialization of sustainable PV systems.