Highly efficient and stable InP/ZnSe/ZnS quantum dot light-emitting diodes
Highly efficient and stable InP/ZnSe/ZnS quantum dot light-emitting diodes
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DOI：
10.1038/s41586-019-1771-5
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发表时间：
2019-11-28
期刊：
影响因子：
64.8
通讯作者：
Jang, Eunjoo
中科院分区：
文献类型：
--
作者：
Won, Yu-Ho;Cho, Oul;Jang, Eunjoo
量子点（QD）发光二极管（LED）是大面板显示器的理想选择，因为它们具有出色的效率，色纯度，可靠性和成本效益的制造（1 - 4）。密集的努力已经生产出效率分别为20.5%（4）、21.0%（5）和19.8%（6）的红色、绿色和蓝色发光QD-LED，但是仍然期望提高器件的操作稳定性，并且用更环境友好的替代物来代替它们的有毒镉成分。磷化铟（InP）基材料和器件的性能远远落后于含镉的同类材料和器件。在这里，我们提出了一种合成方法，制备均匀的InP核和高度对称的核/壳量子点，量子产率约为100%。特别是，我们添加氢氟酸蚀刻出氧化的InP核表面在初始ZnSe壳的生长过程中，然后我们使高温ZnSe生长在340摄氏度。设计的壳层厚度抑制能量转移和俄歇复合，以保持高的发光效率，并且初始表面配体被较短的配体取代，以获得更好的电荷注入。优化的InP/ZnSe/ZnS QD-LED显示出21.4%的理论最大外量子效率，每平方米100，000坎德拉的最大亮度和每平方米100坎德拉的百万小时超长寿命，代表了与最先进的含镉QD-LED相当的性能。这些制备的InP基QD-LED很快就可以用于商业显示器。
Quantum dot (QD) light-emitting diodes (LEDs) are ideal for large-panel displays because of their excellent efficiency, colour purity, reliability and cost-effective fabrication(1-4). Intensive efforts have produced red-, green- and blue-emitting QD-LEDs with efficiencies of 20.5 per cent(4), 21.0 per cent(5) and 19.8 per cent (6), respectively, but it is still desirable to improve the operating stability of the devices and to replace their toxic cadmium composition with a more environmentally benign alternative. The performance of indium phosphide (InP)-based materials and devices has remained far behind those of their Cd-containing counterparts. Here we present a synthetic method of preparing a uniform InP core and a highly symmetrical core/shell QD with a quantum yield of approximately 100 per cent. In particular, we add hydrofluoric acid to etch out the oxidative InP core surface during the growth of the initial ZnSe shell and then we enable high-temperature ZnSe growth at 340 degrees Celsius. The engineered shell thickness suppresses energy transfer and Auger recombination in order to maintain high luminescence efficiency, and the initial surface ligand is replaced with a shorter one for better charge injection. The optimized InP/ZnSe/ZnS QD-LEDs showed a theoretical maximum external quantum efficiency of 21.4 per cent, a maximum brightness of 100,000 candelas per square metre and an extremely long lifetime of a million hours at 100 candelas per square metre, representing a performance comparable to that of state-of-the-art Cd-containing QD-LEDs. These as-prepared InP-based QD-LEDs could soon be usable in commercial displays.