Enhancing Perovskite Solar Cells Performance through Tailored Design: Pyridine-Functionalized Phenothiazine Derivatives with Modified End-Capped Acceptor Moieties

Abstract

Abstract Modifying the end-capped acceptor structural units is a very effective approach to power up the performance of hole-transporting materials. Herein, a new stream of donor- π -acceptor (D- π -A) type pyridine functionalized phenothiazine derivates based donor contributor, resulting in nine newly designed HTMs, by substituting the terminal with thiophene and acceptors moieties respectively to enhance the photovoltaic attributes of perovskite solar cells (PSCs). All newly proposed materials were computationally examined to estimate their optoelectronics, geometrical, and photovoltaic properties using density functional theory (DFT) and time-dependent density functional theory (TD-DFT), and then compared to the reference. For organic hole-transporting materials, a heterocyclic phenothiazine (PTZ) has been proven effective as it has feasible structure modifications, excellent electron-donating properties, and straightforward synthesis. The study of electronic parameters (density of state, frontier molecular orbitals, and electrostatic potential ESP), optical properties (light harvesting efficiency, absorption maxima, dipole moment, and first excitation energies) and charge transfer characteristics (electron-hole overlap, transition density matrix) of designed materials revealed that there is an increase in absorption range under the influence of terminal acceptor groups, with a reduction in bandgap values compared to the reference. A density of state (DOS) graph and HOMO-LUMO schema are evidence of the electron-withdrawing effect of acceptor moieties. Transition density matrix (TDM) analysis proves reliable charger transfer in designed molecules. Reorganization energy values for designed molecules are lower than the reference making charge transfer carriers more efficient. Additionally, solvation-free energy values (-17.28 to -33.19 Kcalmol-1) and higher dipole moments suggest better solubility and surface-wetting properties. In general, our newly derived materials have exceptional charge mobilities with higher absorption and reduced band gap values that make them suitable stable candidates for photovoltaic devices.