Developed non-fullerene acceptors with modified BTPT-OD donor core: A DFT and TD-DFT methods to boost organic solar cell performances

Abstract

In this study, density functional theory (DFT) and time-dependent (TD) DFT were employed in order to conduct electronic structure predictions of four novel non-fullerene acceptors (NF2-NF5) generated from the recently synthesized acceptor BTPT-OD (NF1). We provided detailed information about charge transfer and optoelectronic properties of tailored structures, and we compared them to the reference compound. Compared to the energy gap of the reference molecule (2.09 eV), all developed molecules showed a smaller energy gap (2.00–2.08 eV). The created molecules, NF3 and NF4, exhibit high dipole moments of 8.902 D and 6.988 D, respectively, which may enhance the charge transfer rate. Maximum absorption of NF3-NF5 compounds (λ_max, 686.7–694.6 nm) revealed a red shift in absorption as compared to the primary molecule NF1 (λ_max = 676.9 nm). Based on the earlier research (J. Comput. Chem. 2023, 44, 2130–2148), we employed the recently modified Scharber plot to highlight the role of a narrower electronic gap in the proposed non-fullerene acceptors to enhance the power conversion efficiency. Among all tailored molecules, NF3 showed enhanced photovoltaic parameters; it exhibits a short circuit current density of J_sc = 11.34 mA/cm², an open circuit voltage of V_OC = 1.09 V, and a power conversion efficiency of PCE = 5.35 %, while reference molecule photovoltaic parameters are J_sc = 09.43 mA/cm², V_OC = 1.03 V, and PCE = 4.21 %.