High efficiency solid–liquid hybrid-state quantum dot light-emitting diodes
Quantum dots (QDs) can achieve high quantum yields close to unity in liquid solutions, whereas they exhibit a decreased conversion efficiency after being integrated into solid-state polymer matrices for light-emitting diode (LED) devices, which is called the host matrix effect. In this study, we propose a solid–liquid hybrid-state QD-LED to solve this issue. The ethylene-terminated polydimethylsiloxane (ethylene-PDMS) is used to establish a solid-state cross-linked network, whereas the methyl-terminated PDMS (methyl-PDMS) is used in its liquid state. From a macroscopic level, the cured solid–liquid hybrid-state PDMS (SLHP) composites reach a solid state, which is stable and flexible enough to be used in LED devices. Compared with LEDs using conventional QD/solid PDMS composites at equal color conversion efficiency ranging from 40% to 60%, the luminous flux of LEDs with QD/SLHP composites is increased by 13.0% using an optimized methyl-PDMS concentration of 85 wt. %. As a result, high efficiency QD-LEDs using QDs as the only color convertor with luminous efficacy of 89.6 lm/W (0.19 A) were achieved, which show a working stability comparable with that using conventional solid-state structures at a harsh condition. Consequently, the novel approach shows great potential for achieving high efficiency and high stability QD-LEDs, which is also compatible with current structures used in illumination and display applications.
基金项目：National Natural Science Foundation of China (NSFC)10.13039/501100001809 (51735004, 51775199); Natural Science Foundation of Guangdong Province10.13039/501100003453 (2014A030312017); Science Technology Program of Guangdong Province (2016B010130001).
Yong Tang：Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangzhou 510640, China
Zong-Tao Li：Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangzhou 510640, ChinaFoshan Nationstar Optoelectronics Company Ltd., Foshan 528000, China
Long-Shi Rao：Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangzhou 510640, China
Xin-Rui Ding：Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangzhou 510640, China
Bin-Hai Yu：Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangzhou 510640, China
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Jia-Sheng Li, Yong Tang, Zong-Tao Li, Long-Shi Rao, Xin-Rui Ding, and Bin-Hai Yu, "High efficiency solid–liquid hybrid-state quantum dot light-emitting diodes," Photonics Research 6(12), 1107-1115 (2018)