Numerical analysis of electron and hole transport layer engineering in MASnBr₃-based perovskite solar cells via SCAPS-1D simulation

Lead-free perovskite solar cells represent a sustainable alternative toward toxic lead-based devices. However, the performance of lead-free perovskites has often been challenged due to interfacial losses and instability. Therefore, in this manuscript, SCAPS-1D simulation is conducted in a high-performance lead-free device configuration of FTO/IGZO/MASnBr 3 /CBTS/Ni to gain insight into the role of transport layers and defect control on photovoltaic behavior. An amorphous IGZO electron transport layer is adopted to enable efficient charge extraction with superior optical transparency, while Cu 2 BaSnS 4 acts as an environmentally benign hole transport layer, offering good valence-band alignment with MASnBr 3 . By means of absorber thickness, defect density, and interface recombination velocity parametric optimization, the simulation study revealed that reduction of defect density below 1 × 10 16 cm −3 and optimization of the absorber at ∼900 nm not only enhanced the charge separation but also suppressed nonradiative recombination. The highest PCE of 32.18%, with Voc = 1.1216 V, Jsc = 32.23 mA cm −2 , and fill factor = 89.02%, was realized from this optimized configuration. The synergistic adoption of IGZO and CBTS has thus been addressed, which promotes carrier extraction and stability, hence representing this heterostructure as a promising pathway toward efficient, thermally stable, and nontoxic lead-free perovskite photovoltaics. • SCAPS-1D modeling of IGZO/MASnBr₃/CBTS lead-free solar cells is performed. • Transport-layer engineering suppresses interfacial recombination losses. • Defect and thickness optimization significantly enhance photovoltaic performance. • A record PCE of 32.18% is obtained in an environmentally benign architecture.