Aggregate (Feb 2024)

Aggregation‐induced delayed electrochemiluminescence of organic dots in aqueous media

  • Hang Gao,
  • Shen‐Yu Shi,
  • Shu‐Min Wang,
  • Qian‐Qian Tao,
  • Hui‐Li Ma,
  • Jun Hu,
  • Hong‐Yuan Chen,
  • Jing‐Juan Xu

DOI
https://doi.org/10.1002/agt2.394
Journal volume & issue
Vol. 5, no. 1
pp. n/a – n/a

Abstract

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Abstract Full utilization of the excited species at both singlet states (1R*) and triplet states (3R*) is crucial to improving electrochemiluminescence (ECL) efficiency but is challenging for organic luminescent materials. Here, an aggregation‐induced delayed ECL (AIDECL) active organic dot (OD) containing a benzophenone acceptor and dimethylacridine donor is reported, which shows high ECL efficiency via reverse intersystem crossing (RISC) of non‐emissive 3R* to emissive 1R*, overcoming the spin‐forbidden radiative decay from 3R*. By introducing dual donor‐acceptor pairs into luminophores, it is found that nonradiative pathway could be further suppressed via enhanced intermolecular weak interactions, and multiple spin‐up conversion channels could be activated. As a consequence, the obtained OD enjoys a 6.8‐fold higher ECL efficiency relative to the control AIDECL‐active OD. Single‐crystal studies and theoretical calculations reveal that the enhanced AIDECL behaviors come from the acceleration of both radiative transition and RISC. This work represents a major step towards purely organic, high‐efficiency ECL dyes and a direction for the design of next‐generation ECL dyes at the molecular level.

Keywords