Nonplanar structure accelerates reverse intersystem crossing of TADF emitters: nearly 40% EQE and relieved efficiency roll off.

ABSTRACT: Exploring strategies to enhance reverse intersystem crossing (RISC) is of great significance to develop efficient thermally activated delayed fluorescent (TADF) molecules. In this study, we investigate the substantial impact of nonplanar structure on improving the rate of RISC (k _RISC). Three emitters based on spiroacridine donors are developed to evaluate this hypothesis. All molecules exhibit high photoluminescent quantum yields (PLQYs) of 96-98% due to their rigid donor and acceptor. Leveraging the synergistic effects of heavy element effect and nonplanar geometry, S2-TRZ exhibits an accelerated k _RISC of 24.2 × 10⁵ s^-1 compared to the 11.1 × 10⁵ s^-1 of S1-TRZ, which solely incorporates heavy atoms. Addition

SUBMITTER: Liu H 

PROVIDER: S-EPMC11304530 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature