In:
Optics Letters, Optica Publishing Group, Vol. 47, No. 22 ( 2022-11-15), p. 5873-
Abstract:
An exciplex with significant thermally activated delayed fluorescence properties was realized, comprising diphenyl-[3′-(1-phenyl-1 H -phenanthro[9,10- d ]imidazol-2-yl)-biphenyl-4-yl] -amine as a donor and 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine as an acceptor. A very small energy difference between the singlet and triplet levels and a large rate constant of the reverse intersystem crossing were attained simultaneously, contributing to the efficient upconversion of triplet excitons from the triplet state to the singlet state and thermally activated delayed fluorescence emission. A high-efficiency organic light-emitting device based on the exciplex was fabricated, which exhibited a maximum current efficiency, power efficiency, external quantum efficiency, and exciton utilization efficiency of 23.1 cd/A, 24.2 lm/W, 7.32%, and 54%, respectively. The efficiency roll-off of the exciplex-based device was slight, as illustrated by a large critical current density of 34.1 mA/cm 2 . This efficiency roll-off was ascribed to triplet–triplet annihilation, as confirmed by the triplet–triplet annihilation model. We proved the high binding energy of the excitons and excellent charge confinement within the exciplex by performing transient electroluminescence measurements.
Type of Medium:
Online Resource
ISSN:
0146-9592
,
1539-4794
Language:
English
Publisher:
Optica Publishing Group
Publication Date:
2022
detail.hit.zdb_id:
243290-0
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