Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Nano Lett. 2011 Feb 9;11(2):329-32. doi: 10.1021/nl1021442. Epub 2010 Dec 28.
We report in this communication the design and fabrication of solution-processed white light-emitting diodes (LEDs) containing a bilayer of heavy metal-free colloidal quantum dots (QDs) and polymer in the device active region. White electroluminescence was obtained in the LEDs by mixing the red emission of ZnCuInS/ZnS core/shell QDs and the blue-green emission of poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine). A high color rendering index of 92 was achieved as compared to a 5310 K blackbody reference by virtue of broadband emission of the QDs. The Commission Internationale de l'Eclairage chromaticity coordinates of the white LED output exhibit a distinctive bias dependence. Finally, aging of the white LEDs was studied, revealing the difference between the photochemical stabilities of the QDs and polymer molecules and the consequent effect on the color evolution of the LEDs.
在本通讯中，我们报告了一种设计和制造方法，用于制备含有双层无重金属胶体量子点（QD）和聚合物的溶液处理型白光发光二极管（LED），该双层结构位于器件有源区中。通过混合 ZnCuInS/ZnS 核/壳 QD 的红光发射和聚（N，N'-双（4-丁基苯基）-N，N'-双（苯基）联苯胺）的蓝绿光发射，在 LED 中获得了白色电致发光。与 5310 K 黑体参考相比，由于 QD 的宽带发射，实现了 92 的高显色指数。白色 LED 输出的国际照明委员会色度坐标表现出独特的偏置依赖性。最后，研究了白色 LED 的老化，揭示了 QD 和聚合物分子的光化学稳定性之间的差异，以及这对 LED 颜色演变的影响。
