Reported by Prof. Han YAN

Due to the attraction of optimizing the electronic structure beyond chemical synthesis, molecular doping has recently arounsed wide study interest in organic solar cells. However the selection of limited dopants confines its successful application. Inspired by the Lewis base characteristics of the photovoltaic materials, we introduce the Lewis acid as novel dopant in organic solar cells. In both fullerene and non-fullerene based blends, Lewis acid doping leads to increased photovoltaic performances. Detailed experiments reveal that, Lewis acid doping has a synergistic effect on modifying the polymer’s electronic properties and the acceptor’s nano-structure even at low doping concentration, and these are simultaneously responsible for the device improvements. Based on the mechanism studies, we propose that the Lewis acid doped polymer cations produce induced dipole on the acceptor, this increases the inter-molecular interaction and facilitates the morphology optimization. We believe that the synergistic effect by Lewis acid doping greatly expands the application of doped organic solar cells, in concert with other existing methods to yield higher efficiency values.

The research is finished by the Lab of Organic Optoelectronic Materials and Interfaces which is directed by Prof. Wei Ma. Associate Prof. Han YAN conducted the work as the first author. Prof. Wei Ma and Associate Prof. Han YAN are the corresponding authors. 

The paper is accessed by https://onlinelibrary.wiley.com/doi/full/10.1002/aenm.201703672.

Group website: http://gr.xjtu.edu.cn/web/msewma/home