Synergy of Plasmonic Silver Nanorod and Water for Enhanced Planar Perovskite Photovoltaic Devices

Perovskite solar cells (PSCs) have been widely studied during the past 10 years. Albeit the excellent light‐absorption ability, the thickness of the perovskite layer is limited to maintain effective control over morphology and carrier migration. Meanwhile, the quality of perovskite films is a crucial factor affecting the performance of final devices. The traditional one‐step process for preparing triple‐cation perovskite films suffers from small grain size, low crystallization quality, and many surface defects. Herein, in the process of triple‐cation perovskite‐based solar cells, a facile dosing strategy of a silver nanorods (AgNR) aqueous solution into the perovskite precursor is adopted. The localized surface plasmon resonance effect of AgNR enhances the light‐capture ability of the perovskite layer without increasing the thickness. At the same time, the presence of appropriate water helps to obtain high‐quality perovskite films with larger grain size and fewer defects. It is found that the synergy of AgNR and water successfully reduces the defect density and increases mobility significantly. Consequently, a power conversion efficiency of 20.18% and a short‐circuit current ( J SC ) of 22.08 mA cm −2 is achieved. Meanwhile, an excellent fill factor beyond 82% is reported, which is one of the highest values for triple‐cation hybrid PSCs.