High‐Performance Organic Solar Cells by Adding Two‐Dimensional GeSe

Abstract In organic solar cells (OSCs), the crystalline morphologies of the donor and acceptor at the microscale play an important role. 2D GeSe with periodic structure and high carrier mobility is an ideal additive material for active layer of OSCs that can effectively improve the crystallinity and molecular orientation of the acceptor molecule ITIC. Here, 2D GeSe is introduced into the active layer of OSCs to adjust the morphology of active layer for the first time, the results show that the incorporation of 2D GeSe induces the crystallization of acceptor molecule and facilitates the formation of efficient bicontinuous interpenetrating charge transport networks, and effectively reduces carrier recombination in OSCs. The power conversion efficiency and lifetime of OSCs are obviously enhanced. More importantly, the results of first‐principles calculation reveal that the interaction between 2D GeSe and ITIC guides the ITIC molecules to form a continuous conductive network. This study provides a method for the morphology regulation of the donor and acceptor domains in bulk heterojunctions, provides an idea for researching the interaction between 2D materials and organic molecules, and also indicates that 2D GeSe has good application prospects in photovoltaic devices.