Entropy-driven charge-transfer complexation yields thermally activated delayed fluorescence and highly efficient OLEDs.
Nat Chem
; 16(1): 98-106, 2024 Jan.
Article
in En
| MEDLINE
| ID: mdl-37884666
ABSTRACT
Exciplex-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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nat Chem
Journal subject:
QUIMICA
Year:
2024
Document type:
Article
Affiliation country:
Taiwán