Bulk heterojunction organic photovoltaic cells based on D-A type BODIPY small molecules as non-fullerene acceptors

Wei, T and Dahiya, H and Liang, X and Zhu, W and Pandey, SK and Singh, MK and Xu, H and Sharma, GD (2022) Bulk heterojunction organic photovoltaic cells based on D-A type BODIPY small molecules as non-fullerene acceptors. In: Journal of Materials Chemistry C .

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Abstract

Two non-fullerene small molecule acceptors based on CF3-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) as the central acceptor core and different donor terminal triphenylamine and carbazole units denoted as CF3-BDP-TPA and CF3-BDP-Cz, respectively, were designed and synthesized, and their optical and electrochemical properties were investigated. Both CF3-BDP-TPA and CF3-BDP-Cz showed a narrow bandgap, similar to the well-known Y6 acceptor. The molecular dipole moment of CF3-BDP-Cz is 5.53 D, which is significantly larger than that of CF3-BDP-TPA (3.347 D) and leads to strengthening the intramolecular (C-H⋯π) interaction, thereby enhancing molecular packing. We have used conjugated polymer PBDB-T as the donor (HOMO = −5.22 eV and LUMO = −3.45 eV), having complementary absorption spectra to both CF3-BDP-TPA and CF3-BDP-Cz. The optimized polymer solar cells based on CF3-BDP-TPA and CF3-BDP-Cz attained power conversion efficiencies of 9.89% and 13.07%, respectively. The higher PCE for the CF3-BDP-Cz-based device is linked with the larger dipole moment of CF3-BDP-Cz compared to that of CF3-BDP-TPA, which leads to a lower exciton binding energy and apparently increases both short circuit current and open circuit voltage. The increased value of the fill factor for the CF3-BDP-Cz-based device compared to that of CF3-BDP-TPA counterpart is associated with the balanced charge transport and suppressed recombination processes.

Item Type:	Journal Article
Publication:	Journal of Materials Chemistry C
Publisher:	Royal Society of Chemistry
Additional Information:	The copyright for this article belongs to Royal Society of Chemistry.
Keywords:	Binding energy; Dipole moment; Fullerenes; Heterojunctions; Molecules; Open circuit voltage; Photoelectrochemical cells; Synthesis (chemical), Bulk heterojunction; Carbazole units; Cell-based; Molecular dipole moment; Molecular packings; Narrow bandgap; Organic photovoltaic cell (OPVs); Small molecules; Synthesised; Triphenylamines, Conjugated polymers
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	06 Oct 2022 08:01
Last Modified:	06 Oct 2022 08:01
URI:	https://eprints.iisc.ac.in/id/eprint/77142

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