Fig. 3: The DFT calculation of ETPB conforming to the inherent electron trapping sites.

a The unit cell model of ETPB material for first-principles calculations. b The differential charge mapping of ETPB with Br vacancy, indicating electron trapping sites for Br vacancy. c, d The DOS calculation of ETPB with and without Br2 vacancy, respectively, indicating the electron trapping properties of ETPB. e The theoretical prediction of the Fermi level shift induced by the absence of bromide atoms.