A mini review: Constructing perovskite p-n homojunction solar cells

Organic metal halide perovskite materials have excellent photoelectric properties, and the power conversion efficiency (PCE) of the perovskite solar cells (PSCs) has increased from 3.8% to more than 25%. In the development of PSCs, innovative architectures were being proposed constantly. However, the use of the electron transport layer (ETL) and hole transport layer (HTL) increases manufacturing costs and process complexity. Perovskite material has ambipolar charge transport characteristics, so it could functionalize as both the optical absorption layer and carrier transport layer (CTL). In this review, we analyzed the p/n-type perovskite materials, perovskite p-n homojunction solar cells, and carrier transport layers-free (CTLs-free) devices. Finally, we propose some innovative device architectures. We hope that this mini review could pave way for the simplification of the architectures, promote the preparation of the low-cost and high-efficiency devices, and accelerate the commercialization of the PSCs.