ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

End-capped engineering of benzothiadiazole (BTD3) for enhanced photovoltaic applications: a computational study

Hafiza Nimra Zafar, Najam Ul Hassan, Yasir Altaf, Muhammad Kamran Shehzad, Muhammad Farhan Waris, and Fahim Ahmed

Division of Science and Technology, Department of Chemistry, University of Education, Lahore, Pakistan

E-mail: yasir.altaf@ue.edu.pk

Received: 25 December 2025  Accepted: 17 March 2026

Abstract:

This study investigates the optoelectronic and photovoltaic attributes of six new molecules featuring the unsymmetrical donor molecule benzothiadiazole (BTD3) using density functional theory. Theoretical investigations were carried out at the ωB97XD/6311G level to evaluate parameters such as frontier molecular orbitals (FMOs), absorption spectra, reorganization energy (RE), dipole moment, excitation energy, exciton binding energy, fill factor, and open-circuit voltage. Among designed molecules (B1-B6), B4 exhibits the longest wavelength absorption (543 nm), maximum dipole moment (13.653D), facilitating enhanced charge transfer, indicating its suitability for efficient charge transport. B4 molecule also displays the lowest values of excitation energy in both gas (1.375 eV) and solvent phase (2.282 eV), and the lowest adiabatic IP value (2.11) out of all the molecules explored. B6 shows the highest values of V_OC (2.9 V) and FF (0.973), respectively, showing its strong photovoltaic potential.

Graphical Abstract

Keywords: organic solar cells, density functional theory, energy harvesting, opto-electronics

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04822-5

Chemical Papers 80 (7) 7361–7376 (2026)