Highly
Efficient, Solution-Processed Organic Light-Emitting Diodes Based
on Thermally Activated Delayed-Fluorescence Emitter with a Mixed Polymer
Interlayer
Yanwei Liu
Xiaofang Wei
Zhiyi Li
Jianjun Liu
Ruifang Wang
Xiaoxiao Hu
Pengfei Wang
Yukiko Yamada-Takamura
Ting Qi
Ying Wang
10.1021/acsaem.7b00131.s001
https://acs.figshare.com/articles/journal_contribution/Highly_Efficient_Solution-Processed_Organic_Light-Emitting_Diodes_Based_on_Thermally_Activated_Delayed-Fluorescence_Emitter_with_a_Mixed_Polymer_Interlayer/5873511
The efficiency of
solution-processed organic light-emitting diodes based on pure organic
thermally activated delayed-fluorescence (TADF) emitters is limited
by the hole-injection/severe exciton quenching of poly(styrenesulfonate)-doped
poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) and the exction quenching
of TADF emitters due to the self-aggregation. In order to effectively
enhance the hole-injection from PEDOT:PSS and to alleviate the exciton
quenching of the PEDOT:PSS, the mixed interlayer of poly(9-vinylcarbazole)
(PVK) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-<i>co</i>-(4,4′-(<i>N</i>-(4-s-butylphenyl)diphenylamine))
(TFB) was inserted between emitting layer (EML) and the PEDOT:PSS
layer. Additionally, the cohost of 3′,5′-di(carbazol-9-yl)-[1,1′-biphenyl]-3,5-dicarbonitrile
(DCzDCN) and bis(3,5-di(9<i>H</i>-carbazol-9-yl)phenyl)diphenylsilane
(SimCP2) was used to suppress the self-aggregation of the TADF emitter
of 2-(9-phenyl-9<i>H</i>-carbazol-3-yl)-10,10-dioxide-9
thioxanthone (TXO-PhCz) and tune the charge carrier transport. By
optimizing the mix ratio, highly efficient, solution-processed, green-emitting
TADF-OLEDs with the hole-transport layer (HTL) of TFB:PVK (1:1) and
the EML host of DCzDCN:SimCP2 (1:2) can be turned on at 4 V and can
show a maximum current efficiency (CE) of 55.6 cd/A, a maximum power
efficiency (PE) of 47.2 lm/W, and an external quantum efficiency (EQE)
of 18.86%. The devices are among the most efficient OLEDs fabricated
by solution-processed methods. These results indicate that the employment
of a mixed HTL and EML cohost is a promising way toward the high-efficiency
solution-processed OLEDs.
2018-01-29 00:00:00
carbazol -3-yl thioxanthone
EML cohost
PE
mix ratio
power efficiency
hole-injection
EQE
TADF emitter
self-aggregation
TADF emitters
PEDOT
high-efficiency solution-processed OLEDs
exction quenching
light-emitting diodes
HTL
hole-transport layer
poly
quantum efficiency
carbazol -9-yl
DCzDCN
PVK
Mixed Polymer Interlayer
CE
exciton quenching
Solution-Processed Organic Light-Emitting Diodes
solution-processed methods
EML host
4 V
green-emitting TADF-OLEDs
charge carrier transport
Thermally Activated Delayed-Fluorescence Emitter
TFB