Electronic structure and interfacial features of triphenylamine- and phenothiazine-based hole transport materials for methylammonium lead iodide perovskite solar cells

Abstract

- and the MAI-terminations. We also addressed already known HTM molecular systems to allow for a direct comparison with the recently proposed HTM1: we characterized the molecular parameters and the MAPI/HTM interfacial properties for Spiro-OMeTAD, PTZ1, and PTZ2. Our results suggest that good adhesion properties do not ensure effective and efficient MAPI-HTM hole injection. Despite the theoretical good alignment between HTM1 HOMO and MAPI valence band edge, our results for the mutually polarized interface point out the lack of a sufficient driving force for hole transport. While the hole mobility of HTM1 outperforms those of the other HTM molecules, for this HTM molecule, our findings suggest the application of lead halide perovskite compositions other than MAPI, with substituents that lower its valence band maximum potential value.