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Manipulating spatial alignment of donor and acceptor in host–guest MOF for TADF‡.
- Source :
-
National Science Review . Aug2022, Vol. 9 Issue 8, p1-9. 9p. - Publication Year :
- 2022
-
Abstract
- Thermally activated delayed fluorescence (TADF) was achieved when electron-rich triphenylene (Tpl) donors were confined to a cage-based porous metal-organic framework (MOF) host (NKU-111) composed of electron-deficient 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (Tpt) acceptor as the ligand. The spatially separated donor and acceptor molecules in a face-to-face stacking pattern generated strong through-space charge transfer (CT) interactions with a small energy splitting between the singlet and triplet excited states (∼0.1 eV), which enabled TADF. The resulting Tpl@NKU-111 exhibited an uncommon enhanced emission intensity as the temperature increased. Extensive steady-state and time-resolved spectroscopic measurements and first-principles simulations revealed the chemical and electronic structure of this compound in both the ground and low-lying excited states. A double-channel (T1, T2) intersystem crossing mechanism with S1 was found and explained as single-directional CT from the degenerate HOMO−1/HOMO of the guest donor to the LUMO+1 of one of the nearest acceptors. The rigid skeleton of the compound and effective through-space CT enhanced the photoluminescence quantum yield (PLQY). A maximum PLQY of 57.36% was achieved by optimizing the Tpl loading ratio in the host framework. These results indicate the potential of the MOFs for the targeted construction and optimization of TADF materials. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20955138
- Volume :
- 9
- Issue :
- 8
- Database :
- Academic Search Index
- Journal :
- National Science Review
- Publication Type :
- Academic Journal
- Accession number :
- 159311886
- Full Text :
- https://doi.org/10.1093/nsr/nwab222