基于有机-无机混合配体置换的蓝光量子点发光二极管性能

Performance of Blue Quantum Dot Light-Emitting Diodes Based on Organic-Inorganic Hybrid Ligand Exchange

相较于红光和绿光量子点发光二极管(QLED),制备高效蓝光QLED仍然具有挑战性。比较研究了有机配体(辛硫醇,OT)、无机配体(ZnCl_(2))和有机-无机混合配体(OT和ZnCl_(2))置换原始油酸配体对量子点(QD)的光致和电致发光性能的影响规律及机制。实验结果表明,有机-无机混合配体置换对蓝光QLED的发光性能的提升效果最佳,ZnCl_(2)配体次之,辛硫醇配体最小,这主要归因于三种配体置换后量子点表面缺陷钝化以及量子点价带顶能级上移程度方面的差异。相较于原始油酸配体置换QLED,基于有机-无机混合配体置换量子点蓝光QLED的峰值功率效率和最高外量子效率分别约提高了2.08倍和1.89倍,最高亮度从2413 cd/m^(2)提高到了6994 cd/m^(2)。该研究为调控量子点表面化学性质和提高蓝光QLED性能提供了一种有效策略。

Compared with red and green quantum dot light-emitting diodes(QLEDs),the fabrication of efficient blue QLEDs remains challenging.By exchanging the original oleic acid ligand,the effect laws of organic ligand(octanethiol,OT),inorganic ligand(ZnCl_(2))and organic-inorganic hybrid ligand(OTZnCl_(2))on the photoluminescence and electroluminescence properties of quantum dots(QDs)and their mechanism were comparatively investigated.The experimental results show that organic-inorganic hybrid ligand exchange has the best effect on improving the luminescence performance of blue QLEDs,followed by ZnCl_(2)ligand,and then OT ligand,which is mainly attributed to the difference in the surface defect passivation of quantum dots and the upshift degree of the valence band top energy level of quantum dots shifts upwards after the three ligands exchanges.Compared with the QLED based on original oleic acid ligand exchange,the peak power efficiency and highest external quantum efficiency of the blue QLED based on the organic-inorganic hybrid ligand exchange increase by about 2.08 times and about 1.89 times,respectively,and the highest luminance increases from 2413 cd/m^(2)to 6994 cd/m^(2).The study provides an effective strategy for regulating the surface chemical property of quantum dots and improving the performances of blue QLEDs.