Remarkable performance optimization of inverted p-i-n architecture perovskite solar cell with CZTS as hole transport material

Highlights: • Inverted perovskite solar cell with CZTS as hole transport material (HTM) is fabricated with PCE of 9.72%. • Theoretical optimized device exhibits remarkable PCE of 25.43%. • This study shows CZTS is useful inorganic HTM alternate to traditional organic HTM. Hole transport material (HTM) is a major component of perovskite solar cells (PSCs). PEDOT: PSS, an organic HTM, is widely used in inverted (p-i-n) PSCs. While PEDOT: PSS is unstable, expensive and it's acidic nature could deteriorate the absorber. Copper zinc tin sulphide (CZTS), an inorganic semiconductor can be used as HTM due to its properties such as low cost, ease of synthesis and high hole mobility. In this work, device simulation of inverted (p-i-n) PSC was performed with CZTS as HTM to exploit its maximum capability. Remarkable power conversion efficiency (PCE) of 25.43% was achieved after optimizing the performance. Device performance was strongly affected by thickness and electron affinity of HTM as well as diffusion length of carriers. PCE of real fabricated device was also found to be 9.72%. This work demonstrates CZTS is a promising candidate to replace PEDOT: PSS from both experimental and theoretical perspectives.