PhDMADBr assisted additive or interface engineering for efficient and stable perovskite solar cells fabricated in ambient air

The fabrication of high-quality perovskite films with low defect density in ambient air is an important approach to enhance the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). In this paper, efficient and stable PSCs were fabricated in ambient air, and p-xylilenediamine bromide (PhDMADBr) assisted additive or interface engineering were carried out to modify perovskite films, which was dispersed into the electron transport layer (ETL) or deposited in the ETL/ perovskite interface. Notably, interaction between PhDMADBr and perovskite layer could reduce defect density and release residual stress of the active layer, which would induce a high-quality perovskite film, and accelerate the transport rate and prolong lifetimes of charge carriers, contributing to the PCE and stability of devices. As a result, compared with the PCE of the control device (22.54 %), the PhDMADBr modified target PSCs exhibited the enhanced PCE of 24.15 % and 23.74 % after additive or interface treatments in ambient air, respectively. Except the improvement of the PCE, PhDMADBr-based devices also presented the enhanced moisture stability. The average efficiency retained the 88 % or 84 % of initial efficiency after 120 h with RH of 40 ± 5 % for additive or interface modification, respectively. In contrast, the PCE of the control devices would decline to 51 % of initial efficiency after storage for 120 h.