Nonhydrogenic exciton spectrum in perovskite CH3 NH3 PbI3

The excitons in the orthorhombic phase of the perovskite CH3NH3PbI3 are studied using the effective mass approximation. The electron-hole interaction is screened by a distance-dependent dielectric function, as described by the Haken potential or the Pollmann-Buttner poteial. The energy spectrum and the eigenfunctions are calculated for both cases. The results show that the Pollmann-Buttner mod, using the corresponding parameters obtained from ab initio calculations, provides better agreement with the experimental results. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim