Lin, Chun-YenChun-YenLinHsu, Chao-HsienChao-HsienHsuHung, Chieh-MingChieh-MingHungWu, Chi-ChiChi-ChiWuLiu, Yi-HungYi-HungLiuShi, Emily Hsue-ChiEmily Hsue-ChiShiLin, Tse-HungTse-HungLinHu, Yuan-ChengYuan-ChengHuHung, Wen-YiWen-YiHungKEN-TSUNG WONGPI-TAI CHOU2023-12-042023-12-042023-10-2617554330https://scholars.lib.ntu.edu.tw/handle/123456789/637485Exciplex-forming systems that display thermally activated delayed fluorescence are widely used for fabricating organic light-emitting diodes. However, their further development can be hindered through a lack of structural and thermodynamic characterization. Here we report the generation of inclusion complexes between a cage-like, macrocyclic, electron-accepting host (A) and various N-methyl-indolocarbazole-based electron-donating guests (D), which exhibit exciplex-like thermally activated delayed fluorescence via a through-space electron-transfer process. The D/A cocrystals are fully resolved by X-ray analyses, and UV-visible titration data show their formation to be an endothermic and entropy-driven process. Moreover, their emission can be fine-tuned through the molecular orbitals of the donor. Organic light-emitting diodes were fabricated using one of the D/A systems, and the maximum external quantum efficiency measured was 15.2%. An external quantum efficiency of 10.3% was maintained under a luminance of 1,000 cd m-2. The results show the potential of adopting inclusion complexation to better understand the relationships between the structure, formation thermodynamics and properties of exciplexes.en[SDGs]SDG7journal article10.1038/s41557-023-01357-0378846662-s2.0-85174851113https://api.elsevier.com/content/abstract/scopus_id/85174851113