Quantum Chemical Approach of Donor−π–Acceptor Based Arylborane–Arylamine Macrocycles with Outstanding Photovoltaic Properties Toward High-Performance Organic Solar Cells

Abstract

A theoretical quantum chemical investigation of D−π–A conjugated molecules based on arylborane–arylamine is proposed with the motive of suggesting new organic materials for organic solar cells (OSCs). Optoelectronic properties and geometries of organic donor molecules MC1R–MC1M5 encompassing a caged ring as the donor, thiophene as the bridge, and end-capped moieties as the acceptor are characterized using DFT and TD-DFT. Study involved forecasting the photophysical descriptors such as frontier molecular orbitals, ionization potential, electron affinity, molecular electrostatic potential, transition density matrix, binding energy (Eb), dipole moment, reorganization energy, and open-circuit voltage (VOC) at ground state geometries using the MPW1PW91/6-31G(d,p) basis set. By modulation of end-capped acceptor groups, comprehensive analysis of newly tailored molecules is conducted to reveal insight about π-conjugation contribution on the performance of OSCs. The structure–property relationship of the reference (MC1R) is contrasted with newly organized molecules (MC1M1–MC1M5). The proposed strategy effectively enhanced the absorption (λmax) of all designed molecules. MC1M1 exhibited λmax at 530 nm in DCM (dichloromethane) solvent with the lowest band gap (2.86 eV) and lowest excitation energy of 2.34 eV. An elevated VOC of 2.27 eV is revealed by MC1M4. MC1M2 presented a lowest binding energy of 0.42 eV. The highest hole and electron mobility is ascertained in all newly designed molecules because of their low reorganization energy values which validated preferrable photovoltaic properties as compared to the reference MC1R. MC1M1 showed the lowest electron mobility (λe = 0.009301 eV), and MC1M2 demonstrated the lowest hole mobility (λh = 0.001 874 eV). Our comparative outcomes are proposed to be possible choices for designing efficient OSCs.