Strategic integration of charge transport layers in novel Sr3AsI3 perovskite solar cells for enhanced photovoltaic performance

Abstract Perovskite solar cells (PSCs) have gained immense interest as next-generation photovoltaics due to their impressive power conversion efficiencies (PCEs), ease of fabrication, and low production costs. Despite their potential, practical implementation is hindered by challenges such as interfacial recombination, suboptimal energy band alignment, and stability issues. This study addresses these challenges by investigating a novel perovskite-derived absorber material, Sr 3 AsI 3 , in combination with advanced charge transport layers (CTLs) to enhance device performance. Six distinct PSC configurations were systematically analyzed using polyethyleneimine ethoxylated (PEIE) and tungsten disulfide (WS 2 ) as electron transport layers (ETLs), and copper-based oxides (Cu 2 O, SrCu 2 O 2 ) and molybdenum disulfide (MoS 2 ) as hole transport layers (HTLs). Initial configurations with 300-nm absorbers yielded PCEs in the range of 15.7–24.2%, depending on the CTL combination. A stepwise optimization was conducted by varying absorber thickness, absorber/CTL doping concentrations, and incorporating a reflective back surface. The most significant improvement resulted from increasing absorber thickness to 1200–1250 nm, which enhanced photocurrent collection. Optimized structures with absorber doping concentrations of 1 × 10 17 –1 × 10 18 cm −3 delivered substantially improved efficiencies. Among all cases, the PEIE/Sr 3 AsI 3 /Cu 2 O and WS 2 /Sr 3 AsI 3 /Cu 2 O configurations achieved peak PCEs of 28.52% and 28.50%, with Voc of 0.91 V, Jsc of 35.7 mA/cm 2 , and FF of 87%. These findings demonstrate the effectiveness of absorber thickness and controlled doping optimization in Sr 3 AsI 3 -based PSCs, providing a robust framework for designing stable, high-efficiency perovskite photovoltaics for practical energy applications.