Hydrogen Bond Network for Efficient and Stable Fully Ambient Air-Processed Perovskite Solar Cells with Over 21% Efficiency

Abstract

Chemical passivation serves as a highly effective strategy for mitigating defects to obtain efficient and stable perovskite solar cells. However, concerns about the stability and environmental-friendliness of molecular modulators have emerged with regard to the passivation effect. In this article, we introduce a judicious hydrogen bond network (HBN) composed of imidazole (ImA) and salicylic acid (SA) to address this issue. The ImA-SA HBN features multiple functional groups (amino and carboxyl) that simultaneously passivate various defects, including I – vacancies and uncoordinated Pb 2+ ions located at grain boundaries and surfaces of the perovskite films. Remarkably, the ImA-SA HBN effectively bridges perovskite grains and interfaces between the perovskite films and hole transport materials, which enhances the transport of photogenerated carriers. Moreover, cyclic ImA-SA, characterized by steric hindrance, inhibits ion migration derived from grain boundaries of the perovskite films. Consequently, the efficiency of the champion device processed in fully ambient air exceeded 21% and did not decline obviously after 3380 h of storage in the air environment (20 ± 5 °C, 30 ± 5% RH, and without encapsulation). This work offers a promising approach to diminishing the defects in perovskite grain boundaries and surfaces, enhancing optoelectronic properties and facilitating the creation of efficient and stable perovskite solar cells processed in fully ambient air.