Polyethylene Glycol Dodecyl Ether as Interfacial Modifier for Improving Efficiency of Perovskite Solar Cells

The rapid development of the perovskite solar cell (PSC) makes its best research efficiency comparable with that of silicon solar cells. However, the large‐scale application of PSCs still faces the dual challenges of improving efficiency and stability. Herein, an interfacial modifier of polyethylene glycol dodecyl ether (Brij) with ether group (C–O–C) and long alkyl chain is introduced into the interface of the perovskite layer and hole transport layer. It is demonstrated that the interaction of the ether group on Brij with uncoordinated lead ions on the perovskite passivates the point defects and reduces carrier recombination. The introduction of Brij tunes the energy gradient among electron transport layer/perovskite layer/hole transport layer and promotes the carrier extraction and transportation. The long alkyl chain of Brij covers the surface of perovskite and effectively improves the moisture resistance of perovskite films and the environmental stability of devices. Under an optimal Brij concentration, the modified perovskite solar cell achieves the best power conversion efficiency of 22.57%, along with improved environmental stability, while the pristine device obtains an efficiency of 20.66%.