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题目:
High-Efficiency Quantum Dot Light-Emitting Diodes Employing Lithium Salt Doped Poly(9-vinlycarbazole) as a Hole-Transporting Layer
 
 
作者:
Ying-Li Shi, Feng Liang, Yun Hu, Xue-Dong Wang, Zhao-Kui Wang, and Liang-Sheng Liao*
 
 
单位:
Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Centre of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123, China.
 
 
摘要:
For the purpose of fabricating solution-processed quantum-dot light-emitting diodes (QLEDs) with high performance, the efficient hole-electron recombination at low current density is particularly pivotal. Herein, to enhance the charge balance of the QLED device, we employ the lithium bis (trifluoromethylsulfonyl) imide (Li-TFSI) as a p-type dopant into the hole-transporting material (HTM) of poly(9-vinlycarbazole) (PVK). In the experiment, the increased conductivity and the enhanced charge mobility of the Li-TFSI-doped PVK layer were confirmed by the J-V curves of the hole-only devices and the conductive atomic force microscopy (c-AFM). Furthermore, on combining the ultraviolet photoelectron spectroscopy (UPS) and the absorption spectrar, it was found that the highest occupied molecular orbital (HOMO) of the Li-TFSI-doped PVK layers gradually shifted closer to the Fermi level upon increasing the doping ratios from 0 to 4.5 wt%. Therefore, the hole-injecting barrier decreases from 1.17 eV to 0.64 eV. As a result, the maximum current efficiency, and the highest external quantum efficiency (EQE) of our fabricated QLED devices can reach as high as 15.5 cd/A, and 11.46%, respectively. It was demonstrated that the p-type dopant Li-TFSI in  the HTM can contribute to the fabrication of high-performance solution-processed light-emitting diodes.
 
 
影响因子:
5.066
 
 
分区情况:
一区
 
 
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