Nonhydrogenic exciton spectrum in perovskite CH₃NH₃PbI₃

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–Büttner potential. The energy spectrum and the eigenfunctions are calculated for both cases. The results show that the Pollmann–Büttner model, using the corresponding parameters obtained from ab initio calculations, provides better agreement with the experimental results. magnified image (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)