A first-principles prediction on the "healing effect" of graphene preventing carrier trapping near the surface of metal halide perovskites.

ABSTRACT: We herein report that surface modification of metal halide perovskites using graphene would be beneficial to improving the energy conversion efficiencies of perovskite solar cells. The present first-principles calculations on MAPbI₃ with a single vacancy created by removing either I, Pb or MA show that the I and Pb vacancies near the surface result in the formation of Pb-Pb and I-I dimers, respectively. They are predicted to yield mid-gap levels, and would degrade the energy conversion efficiency of perovskite solar cells through carrier trapping. The present calculations suggest that when the surface of MAPbI₃ is covered with a graphene sheet, the formation of the carrier trapping dimers would be suppressed. The origin of the "healing effect" of graphene on the latti

SUBMITTER: Wang WW 

PROVIDER: S-EPMC5932977 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature