Molecular engineering of tetraphenyl-based hole transporting materials to enhance photovoltaic properties of perovskite solar cells

Abstract

Perovskite photovoltaic cells have lately gained appeal due to their excellent operational efficiency, photophysical properties, and high dielectric constant. Five novel hole transport materials namely TADM1–TADM5 were devised to improve power conversion efficiency (PCE) of Perovskite solar cells (PSCs). These molecules have tetraphenyl (TP) as a typical core, donor, and different acceptor units connected via a thiophene spacer. Under the framework of DFT theory, the B3LYP functional along with the 6–31 G basis set was utilized to study their geometries, molecular electrostatic potential, reorganization energies, the density of states, quantum chemical parameters, transition density matrix, binding energies, and charge transfer properties. All the designed HTMs (TADM1–TADM5) displayed excellent photovoltaic properties due to lower (Eg) varying (1.94–2.54 eV), small binding energies (0.04–0.36 eV), and high dipole moments (12.89 D to 26.93 D) that enhanced their electron charge transfer behavior. Small reorganization energy (RE) values for holes and electrons resulted in significant charge mobility. All the designed HTMs (TADM1-TADM5) have higher VOC (1.30–1.43 V) and power conversion efficiency (23.70–26.27%) than the reference molecule SMeTAD (20.94%). Consequently, all of the modelled molecules (TADM1-TADM5) demonstrate that using acceptor moieties is an effective method for achieving acceptable optoelectronic characteristics and outstanding efficiency.