Realization of Efficient Phosphorescent Organic Light-Emitting Devices Using Exciplex-Type Co-Host

High-performance phosphorescent organic light-emitting devices with an exciplex-type co-host were fabricated. The co-host is constituted by 1,3,5-tris(N-phenylbenzimidazol-2-yl) benzene, and 4,4,4-tris (N-carbazolyl) triphenylamine, and has obvious virtues in constructing efficient devices because o...

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Bibliographic Details
Published in:Micromachines (Basel) 2021-12, Vol.13 (1), p.51
Main Authors: Wu, Lishuang, Xu, Huiwen, Yang, Huishan
Format: Article
Language:English
Subjects:
Benzene
Critical current density
Devices
Efficiency
Energy transfer
exciplex
Excitons
Fluorescence
Hydrocarbons
Organic light emitting diodes
Phosphorescence
Quantum efficiency
reverse intersystem crossing (RISC)
thermally activated delayed fluorescence (TADF)
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Summary:High-performance phosphorescent organic light-emitting devices with an exciplex-type co-host were fabricated. The co-host is constituted by 1,3,5-tris(N-phenylbenzimidazol-2-yl) benzene, and 4,4,4-tris (N-carbazolyl) triphenylamine, and has obvious virtues in constructing efficient devices because of the thermally activated delayed fluorescence (TADF) resulting from a reverse intersystem crossing (RISC) process. The highest external quantum efficiency and luminance are 14.60% and 100,900 cd/m for the optimal co-host device. For comparison, 9.22% and 25,450 cd/m are obtained for a device employing 4,4,4-tris (N-carbazolyl) triphenylamine as a single-host. Moreover, the efficiency roll-off is notably alleviated for the co-host device, indicated by much higher critical current density of 327.8 mA/cm , compared to 120.8 mA/cm for the single-host device. The alleviation of excitons quenching resulting from the captured holes and electrons, together with highly sufficient energy transfer between the co-host and phosphorescent dopant account for the obvious boost in device performances.
ISSN:2072-666X
2072-666X
DOI:10.3390/mi13010051