Zwitterions: promising interfacial/doping materials for organic/perovskite solar cells

Abstract

Zwitterions, due to their unique chemical structures and electric charges, have attracted continuous attention in organic/perovskite solar cells (OSCs/PSCs). They are widely used as interfacial materials in both OSCs and PSCs, and have been recently exploited as excellent dopants to passivate the defects and stabilize the black phase of perovskite films. This review summarizes the recent progress in zwitterionic materials toward their application in OSCs and PSCs, through the concepts of interfacial dipoles and their functions as interlayers, and the discussion on the regulation of perovskite films. In terms of interfacial modification, ultrathin zwitterionic materials, thickness-insensitive zwitterionic materials applied on metals and zwitterionic materials applied on metal oxides are listed. Based on their functions, zwitterionic dopants are described in terms of passivating defects and stabilizing phase.