I will present an approach formally based on many-body perturbation theory which introduces the coupling with longitudinal phonons in the evaluation of the self-energy for the GW method and in that of the electron-hole effective interaction for the BSE one. Our scheme allows for calculations of properties such as band-gap and effective masses renormalisation, electron and hole mobilities and exciton binding energies. As the electron-phonon interaction is modelled directly from the Infrared response, these calculations are particularly inexpensive in terms of computer resources and can be seen as a post-processing of DFT or ordinary GW-BSE runs. First, I will discuss the calculation of excition-binding energies in MAPbI3 [1] showing how the inclusion of electron-phonon interactions lowers the binding energy from 30 meV to 15 meV, while cation rotations play only a marginal role resulting in oscillations of the exciton binding energy within a 2 meV range. Then, I will talk about the calculation of electron and hole relaxation times in MAPbI3 showing how our simple scheme is in agreement with previous full electron-phonon calculations. I will clarify the role of different vibrations in the make up of the mobilities showing the implications for other solar-cell perovskites.

[1] P. Umari, E. Mosconi, F. De Angelis, J. Phys. Chem. Lett. 9, 620 (2018).