Tailored multifunctional hydrazine derivatives for efficient printable hole-conductive-free mesoscopic perovskite solar cells via enhancing defect passivation

The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells (p-MPSCs) are overshadowed by their limited photovoltaic conversion efficiency (PCE). Here, we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine (4-HBH) to improve the PCE of p-MPSCs by inducing enhanced defect passivation. Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite. The hydroxyl group, as an electron donor group, increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring, and thus enhances its interaction with perovskite. Additionally, the hydroxy group itself interacts with perovskite and passivates defects synergistically. The hydrazine agents can also reduce I2 and suppress the loss of iodine in perovskite films, which inhibits the formation iodine-related defects. Consequently, p-MPSCs with 4-HBH achieve a high PCE of 19.21%, and present well improved stability.