Tuning the photovoltaic parameters of ZnII porphyrin-based hole-transport materials by donor substitution strategy

Abstract

We used quantum chemical methods to conduct theoretical studies on the promising experimental HTM molecule MDA4 (Zn^II porphyrin ring as the core and diarylamine as the donor) and molecules designed based on this molecule by substitution with donor groups (named MDA4-Z1, MDA4-Z2, and MDA4-Z3), including geometric structure, electronic properties, excited state properties, and hole mobility, etc. The research results indicate that the designed molecules all have excellent light absorption properties, which is beneficial for increasing the short-circuit current density of the molecule. These molecules also have good charge transfer performance. The maximum absorption peak wavelengths of the designed molecules are all blue-shifted compared to the experimental molecule MDA4. The solubility of molecules MDA4-Z1 and MDA4-Z3 are similar to those of experimental molecules MDA4. The hole mobility of all designed molecules has been significantly improved compared to the experimental molecule MDA4, with MDA4-Z3 having the highest hole mobility. It is worth noting that MDA4-Z3 exhibits the best comprehensive performance among numerous designed molecules, which makes it a potential ideal HTM.