A facile surface trap passivation of perovskite absorber enabled by tetrabenzocorrolazine dye for efficient and stable planar perovskite solar cells

The trap-site passivation of perovskite absorbers is very important for reducing charge recombination and resultant energy loss in high-performance perovskite solar cells (PSCs). To achieve the successful role of a passivating agent, an appropriate molecular design strategy with specific functional groups should be considered for effective passivation of the defective antisites on the surface of perovskite absorber layers. Here, we designed a tetrabenzocorrolazine phosphorus dye (RC1), that is capable of electron-donating properties with a hydroxyl functionalization, as a multi-functional passivation agent for high-performance PSCs. It is found that the surface properties of the perovskite absorber were stabilized as RC1 interacts with Pb2+ and Cs + cations of the perovskite lattice, providing much improved optoelectronic properties and their charge extraction/collection capability. Moreover, the RC1-passivation successfully reduced carrier recombination and internal energy loss, leading to hysteresis-free power conversion efficiency of 18.922% (14.466% for the control device). The RC1 also retains long-term stability for 2000 h with only 10% efficiency loss of the fresh device. Thus, this study demonstrates a successful passivating capability of functionalized tetrabenzocorrolazine phosphorus dye for high-performance PSCs.