High Conduction Band Polymer Acceptor as a Ternary Component for Indoor Power Generation and Photodiode: Enhanced Photovoltage and Suppressed Dark Current

초록

We explore the application of a high conduction band polymer acceptor (IDSIC-BTI) as a ternary component in indoor organic photovoltaic cells (IOPVs) and organic photodiodes (OPDs). IDSIC-BTI shows a 1.91 eV electrochemical band gap and a high-lying lowest unoccupied molecular orbital (LUMO) of -3.78 eV. Its compatibility and miscibility with nonfullerene acceptors (NFAs) stem from shared electron-deficient structural elements. Combining IDSIC-BTI with NFAs such as IT-4F and Y6 yields smooth surface morphologies and elevates LUMO levels due to the formation of acceptor-acceptor (A-A) alloys. This heightened LUMO level within the A-A alloy structure contributes to the expansion of the energy gap associated with charge-transfer states (E-CT) in ternary blends using PM6 as a donor polymer. As a direct consequence of this effect, these ternary blends exhibit an increased open-circuit voltage (V-OC) and decreased dark current density (J(D)). For IOPV applications, incorporating IDSIC-BTI into the PM6:IT-4F blend enhances the V-OC (from 0.70 to 0.75 V) and raises power conversion efficiency from 20.9 to 22.9%. In OPD devices, the ternary PM6:Y6:IDSIC-BTI blend demonstrates a 1.7 times higher specific detectivity of 5.71 x 10(12) Jones compared to binary OPD while effectively reducing J(D). These findings may suggest effective strategies for regulating V-OC and J(D) in IOPV and OPD devices through the strategic inclusion of a third component.

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