Surface passivation of perovskite with organic hole transport materials for highly efficient and stable perovskite solar cells

Perovskite solar cells (PSCs) have become a hot spot in the field of photovoltaic research in recent years due to their low fabrication costs and rising efficiencies. However, the performance and stability degradation caused by defect states in metal halide perovskites are the main constraint to the development of PSCs. At present, researchers have successfully designed and synthesized a series of organic hole transport materials (HTMs) with excellent passivation function by introducing passivation functional groups into the structure of HTMs to passivate the defects in perovskite films, effectively improving the performance and stability of PSCs. Herein, we review the recent progress of organic HTMs with defect passivation function for efficient and stable PSCs. We mainly introduce some representative organic HTMs with passivation function, summarize and comment on their photovoltaic parameters, and explore the effect of passivation groups on their performance. Finally, we provide a guideline for the future design of novel and efficient HTMs with defect passivation based on current research.