Simulation of inverted perovskite solar cells

A planar perovskite solar cell (PSC) with p-i-n inverted structure was modeled and simulated to determine the power output characteristics under illumination. The performance of inverted PSC device was correlated to the thickness of the absorber layer, band alignment, and electrical properties of the hole transport materials (HTMs). Our simulation indicates that, with an optimized absorber layer thickness ~300 nm, an efficiency of 18% can be achieved. This baseline device was further utilized to investigate the role of band offset between the HTM and absorber layer. Results show that the device efficiency can be improved to 24% when the work function of HTM is reduced to 0.1 eV lower than the valence band edge of perovskite. Parametric studies were carried out to compare the feasibility of five different HTMs including spiro-OMeTAD, Cu2O, CuSCN, NiO, and CuI. Among them, NiO is the most promising candidate with a theoretical efficiency limit up to 27%. This work would serve as a modeling frame to simulate and interpret the performance of inverted PSCs and suggest further device optimization strategies.