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Highly Efficient All-Solution Processed Inverted Quantum Dots Based Light Emitting Diodes

delete2018-01-30
delete136
PRE
AI
Y
Yu Liu
C
Congbiao Jiang
S
Song Chen
J
Juanhong Wang
L
Lan Mu
何志伟 (Zhiwei He)
Z
Zhenji Zhong
寸阳珂 (Yangke Cun)
C
Chaohuang Mai
J
Jian Wang *
彭俊彪 (Junbiao Peng)
曹庸 (Yong Cao)
DOI:10.1021/acsnano.7b08129delete
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Abstract

Abstract

En 中文
In all-solution processed inverted quantum dots based light emitting diodes (QLEDs), the solvent erosion on the quantum dot (QD) layer prevents devices from reaching high performance. By employing an orthogonal solvent 1,4-dioxane for the hole transport layer (HTL) poly(9-vinlycarbazole) (PVK), the external quantum efficiencies (EQE) of red QLED is increased 4-fold, while the luminous efficiencies (LE) of blue QLED is enhanced by 25 times, compared to the previous devices' record. To further improve the device efficiency and reduce the efficiency roll-off, solution processed PVK/poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB) double-layer HTL is introduced to facilitate hole injection with stepwise energy level. By reducing the hole injection barrier, the turn-on voltage of QLEDs decreases from 3.4 to 2.7 V for red, from 5.1 to 2.7 V for green, and from 5.3 to 4.1 V for blue. The peak LE reach 22.1 cd/A, 21.4 cd/A, and 1.99 cd/A, while the maximum EQE reach 12.7%, 5.29%, and 5.99%, for red, green, and blue QLEDs, respectively. To the best of our knowledge, the red and blue QLEDs exhibit the best device performance among all the all-solution processed inverted QLEDs. In addition, the blue QLED is the champion among all the inverted QLEDs, including the devices fabricated by thermal evaporation.
Keywords:
light emitting diodes
quantum dots
solution process
orthogonal solvent
hole transport layer
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Journal

ACS Nano cover
ACS Nano
IF:
16
Papers:
2.6W
Citations:
25.6W

Organization

S
south china university of technology
Scholars:
6.6W
Papers: 5.0W
Citations: 85