https://doi.org/10.1140/epjp/s13360-025-06659-5
Regular Article
Enhanced organic photovoltaic performance of end-capped non-fullerene acceptor molecules: a TD-DFT analysis
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 210094, Nanjing, People’s Republic of China
Received:
22
January
2025
Accepted:
15
July
2025
Published online:
31
July
2025
Researchers were under pressure to discover new energy sources and enhance the effectiveness of existing technologies due to the increasing global demand for renewable energy sources. One of the most promising answers to the energy and climate crises is solar energy, which generates energy without contaminating the environment and is stable over a long duration. Here, modification in the donor–acceptor 1-acceptor 2 (D-A1-A2) design has been used to rationally construct non-fullerene acceptors (NFAs) molecules A1-A6 derived from a compound 5-(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)-N,N-dip-tolylthiophen-2-amine (TNBO) for organic solar cells (OSCs). The impact of A1-A6 was examined using the density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. This was achieved by examining the properties of charge transfer (CT), photovoltaic (PV), reorganization energies (RE), frontier molecular orbitals (FMOs), maximum absorption wavelength (λmax), and other relevant parameters. The molecules with the smallest energy gaps (Eg) among all were A3 (1.96 eV) and A4 (1.94 eV) because of the effect of end-capped acceptors. All derivatives have very low excitation energy Ex (1.63–1.81 eV) and very large λmax (683–759 nm), especially A4 has an Ex of 1.63 eV and λmax of 759 nm. The λe and λh values of A4 (0.0162 eV and 0.0052 eV, respectively) indicate that these molecules have plausible electron transportation, as evidenced by their lower values of λh than λe. Besides, all compounds exhibit the highest open-circuit voltage (Voc) with PTB7-Th, which ranges from 1.80 to 1.86 eV. The highest Voc has achieved specifically around 1.86 eV on A4. The six differently created compounds demonstrate beneficial CT characteristics, high excitonic generation with low excitation energy (Ex), easier charge separation, and raised Voc. At a short circuit current, density (Jsc) of 12.4 mA.cm2 has reached power conversion efficiencies (PCE) ranging from 20.65 to 21.39%. In particular, the PCE of 21.39% for NFAs-based OSCs was obtained with the highest value for molecule A4. The potential application of these engineered compounds with distinct end-capped A-groups as innovative building blocks for renewable energy sources. Constructive nonlinear optical (NLO) outcomes were framed for every derivative, indicating that the greatest dipole moment (µ), polarizability (α), and hyperpolarizabilities (β) greater than those of the TNBO. A4 exhibits the highest significant NLO response (µ = 13.78 D, α = 3.70 esu, and β = 9.31 esu). A major contributing factor to achieving beneficial NLO activity has been a computationally modeled strategy that makes use of the end acceptors. Finally, the insightful results of these molecules might open up new avenues for developing the optoelectronic characteristics of effective OSCs and NLO materials, particularly A4.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
