High-performance carbon-based perovskite solar cells through the dual role of PC61BM

Abstract

Carbon-based HTM-free perovskite solar cells (C-PSCs) have received extensive attention due to their low cost and high stability. However, some issues with regard to their relatively low efficiency and toxicity still need to be addressed before their commercialization. For the first time, a high-efficiency carbon-based planar perovskite solar cell was prepared based on TiO₂ combined with PC₆₁BM as the electron-transport layer. PC₆₁BM could passivate the interface between the perovskite film layer and the TiO₂ film layer; at the same time, it also exhibited the function of an additive to improve the crystal quality of the perovskite. Planar C-PSC was successfully fabricated with an open voltage (V_oc) of 1.005 V, which represented ∼2.6% enhancement compared to that of the device with a mesoporous structure, and power conversion efficiency (PCE) of 14.37%. Moreover, stability was also investigated; 3% degradation appeared in the PCE of the planar C-PSC after being stored for 1900 h in the dark. This methodology of introducing PC₆₁BM to reduce the recombination probability of electrons and holes and improve the crystal quality of perovskites has universal significance for the further development of planar C-PSCs.