Suppressing electron-phonon coupling in organic photovoltaics for high-efficiency power conversion.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37604923.
- Also identified by DOI 10.1038/s41467-023-40806-9 and PMC identifier 10442373.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The nonradiative energy loss (∆E<sub>nr</sub>) is a critical factor to limit the efficiency of organic solar cells. Generally, strong electron-phonon coupling induced by molecular motion generates fast nonradiative decay and causes high ∆E<sub>nr</sub>. How to restrict molecular motion and achieve a low ∆E<sub>nr</sub> is a sticking point. Herein, the free volume ratio (FVR) is proposed as an indicator to evaluate molecular motion, providing new molecular design rationale to suppress nonradiative decay. Theoretical and experimental results indicate proper proliferation of alkyl side-chain can decrease FVR and restrict molecular motion, leading to reduced electron-phonon coupling while maintaining ideal nanomorphology. The reduced FVR and favorable morphology are simultaneously obtained in AQx-6 with pinpoint alkyl chain proliferation, achieving a high PCE of 18.6% with optimized V<sub>OC</sub>, J<sub>SC</sub> and FF. Our study discovered aggregation-state regulation is of great importance to the reduction of electron-phonon coupling, which paves the way to high-efficiency OSCs.