Benzotriazole derivative inhibits nonradiative recombination and improves the UV-stability of inverted MAPbI3 perovskite solar cells

Abstract

Suppressing the nonradiative recombination in the bulk and surface of perovskite film is highly desired to improve the power conversion efficiency (PCE) and stability of halide perovskite solar cells (PSCs). In this study, a benzotriazole derivative (6-chloro-1-hydroxybenzotriazole, Cl-HOBT) is applied to improve the crystallinity and reduce the trap density of methylammonium lead iodide (MAPbI3) perovskite film. Meanwhile, incorporation of Cl-HOBT elongates the photoluminescence carrier lifetime and charge-recombination lifetime, implying the trap-assisted nonradiative recombination is greatly suppressed. Besides, the improved energy level alignment and enhanced built-in potential are conducive to the charge carrier separation and transfer process with Cl-HOBT. Consequently, a PCE of 20.27% and an open-circuit voltage (Voc) of 1.09 V are achieved for the inverted MAPbI3 PSCs, along with an 85% maintaining of the initial PCE under stored at relative humidity of 20% for 500 h. Furthermore, the existence of Cl-HOBT could inhibit the formation of Pb0 defect under prolonged UV illumination to retard the degradation of perovskite film. It is believed that this study paves a novel path for the realization of high-efficiency PSCs with UV-stability.