Conductive chelating agent-treated electron transfer layers for environmentally friendly and efficient perovskite solar cells

Abstract

The electron transfer layer (ETL) adjacent to the pivotal perovskite layer has significant effects on the ultimate performance of perovskite solar cells (PSCs). Exquisite improvement of ETLs is feasible to elevate the already impressive photoelectric characteristics of PSCs. Herein, a multifaceted conductive chelating agent, sodium p-styrenesulfonate (SSS), is incorporated into SnO₂ precursor solution to improve the performance of PSCs. Our results indicate that SSS can regulate crystal growth of SnO₂, passivate vacancy oxygen traps of the formed SnO₂ ETL, and further strengthen the interface contact. In addition, SSS molecules can also adjust the growth of perovskite crystals and improve the quality of perovskite films. Furthermore, SSS molecules in the SnO₂ ETL can provide in situ suppression of lead leakage by chelating with dissociative Pb²⁺. Finally, the photoelectric conversion efficiency of PSCs is increased from 21.45% to 24.23% with enhancement in the conductivity of the SnO₂ ETL and the electron transport at the SnO₂/perovskite interface. Simultaneously, SSS-optimized PSCs exhibit improved storage and operational stability, as well as in situ fixation of dissociative Pb²⁺. This promotion of both the SnO₂ ETL and the perovskite layer via adding a conductive chelating agent to the SnO₂ precursor solution provides a convenient strategy to effectively improve the performance and stability of environmentally friendly PSCs.