Efficient and stable perovskite solar cells via surface defect passivation using 4-fluorobenzamine trifluoroacetate†

Abstract

Perovskite solar cells (PSCs) have achieved high power conversion efficiencies (PCEs). However, surface defects present a major challenge to further improving their performance. Fluorine-substituted materials have been widely utilized to passivate surface defects and improve the photovoltaic performance and stability of PSCs. In this study, post-treatment of the methylamine-lead iodide (MAPbI₃) perovskite surface was performed using 4-fluoroaniline trifluoroacetate (P-F-PMATFA), and the surface defects of the perovskite were passivated via an F atom, which reduced the energy barrier between the perovskite film (PVK) and hole transport layer (HTL). Consequently, the PCE of P-F-PMATFA treated solar cells based on the MAPbI₃ perovskite increased from 19.19 to 21.01% with low open-circuit voltage (V_OC) loss (0.44 V). Further, P-F-PMATFA treated perovskite devices exhibited long-term stability, owing to the higher hydrophobicity of fluorinated materials. The post-treatment strategy demonstrated in this study shows wide application potential in the field of photovoltaic devices owing to its ability to passivate surface defects and improve material stability.