Asymmetric Non-Fullerene Acceptor Derivatives Incorporated Ternary Organic Solar Cells

Abstract

Incorporating ITIC derivatives as guest acceptors into binary host systems is an effective strategy for constructing high-performance ternary organic solar cells (TOSCs). In this work, we introduced A−D−A type ITIC derivatives PTBTT-4F (asymmetric) and PTBTP-4F (symmetric) into the PM6:BTP-BO-4F (Y6-BO) binary blend and investigated the impacts of two guest acceptors on the performance of TOSCs. Differentiated device performance was observed, although PTBTT-4F and PTBTP-4F presented similar chemical structures and comparable absorptions. The PTBTT-4F ternary devices exhibited an improved power conversion efficiency (PCE) of 17.67% with increased open circuit (V OC ) and current density (J SC ), whereas the PTBTP-4F-based ternary devices yielded a relatively lower PCE of 16.34%. PTBTT-4F showed much better compatibility with the host acceptor BTP-BO-4F, so that they formed a well-mixed alloy phase state; more precise phase separation and increased crystallinity were thus induced in the ternary blends, leading to reduced molecular recombination and improved charge mobilities, which contributed to improved fill factors of the ternary devices. In addition, the optimized PTBTT-4F devices exhibited good performance tolerance of the photoactive layer thickness, as they even delivered a PCE of 15.25% when the active layer was as thick as up to ∼300 nm.

A high-efficiency and stable organic solar cell with balanced crystallization kinetics

“…13–15 Moreover, the addition of single-component based guests (for ternary blends) tends to restrain the absorption complementarity of photoactive layers. 16–18 To widen the absorption of OSCs and better control the nanomorphology and carrier transport, 18–23 the approach based on quaternary blends has been proposed. 24–28 For example, by introducing a co-donor and a co-acceptor (co-DA) into the host blends, the inter-percolated charge transport networks in the quaternary OSCs were improved, leading to a certified power conversion efficiency (PCE) of over 19%.…”