Optimal design and performance assessment of CH3NH3SnBr3 lead-free perovskite solar cells for > 24% efficiency

Recent breakthroughs based on lead (Pb) halide perovskites have inspired extensive study into low-cost photovoltaics to overcome the major challenges that come in this space: stability and toxicity. This work undertook the device configuration of a lead-free perovskite solar cell (PSC) to adopt (CH3NH3SnBr3) methylammonium tin bromide perovskite as an absorber layer. The perovskite solar cell was built with the perovskite CH3NH3SnBr3 as the light absorber layer, Spiro-OMeTAD as the hole transport layer, and a comparative evaluation of various electron transport layers (ETLs) was performed depending on conduction band offsets. CdZnS excelled the other suggested ETLs, with a 24.05% power conversion efficiency. The efficiency of the solar cell was also improved by modifying the doping density in the ETL, the perovskite light absorber layer's thickness, and the HTL layer. The ETL based doping concentrations for the CdZnS (1021 cm−3) and Spiro-OMeTAD (1020 cm−3) were discovered to be the most effective for displaying increased efficiency. 600 nm thick perovskite layer was acceptable for the efficient design. These findings represent the photovoltaic device's best performance; it will be employed to design PSC with high efficiency.