Park Sang Hyun, Hong Ara, Kim Jong-Hoon, Yang Heesun, Lee Kwangyeol, Jang Ho Seong
†Materials Architecturing Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea.
‡Department of Chemistry, Korea University, Seoul 136-701, Republic of Korea.
ACS Appl Mater Interfaces. 2015 Apr 1;7(12):6764-71. doi: 10.1021/acsami.5b00166. Epub 2015 Mar 18.
In this study, we report bright yellow-green-emitting CuInS2 (CIS)-based quantum dots (QDs) and two-band white light-emitting diodes (LEDs) using them. To achieve high quantum efficiency (QE) of yellow-green-emitting CIS QDs, core/shell/shell strategy was introduced to high quality CIS cores (QE = 31.7%) synthesized by using metal-oleate precursors and 1-dodecanethiol. The CIS/ZnS/ZnS QDs showed a high QE of 80.0% and a peak wavelength of 559 nm under the excitation of 450 nm, which is well matched with dominant wavelength of blue LEDs. The formation of core/shell/shell structure was confirmed by X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-optical emission spectroscopy analyses. Intense and broad yellow-green emission band of the CIS/ZnS/ZnS is beneficial for bright two-band white light. When the CIS/ZnS/ZnS was coated on the blue LEDs, the fabricated white LED showed bright natural white light (luminous efficacy (η(L)) = 80.3 lm·W(-1), color rendering index (R(a)) = 73, correlated color temperature (T(c)) = 6140 K). The QD-white LED package showed a high light conversion efficiency of 72.6%. In addition, the CIS/ZnS/ZnS-converted white LED showed relatively stable white light against the variation of forward bias currents of 20-150 mA [color coordinates (x, y) = (0.3320-0.3207, 0.2997-0.2867), R(a) = 70-72, T(c) = 5497-6375 K].
在本研究中，我们报道了基于亮黄绿色发光的硫化铜铟（CIS）量子点（QDs）以及使用它们的双波段白光发光二极管（LEDs）。为实现黄绿色发光CIS量子点的高量子效率（QE），我们将核/壳/壳策略引入到通过金属油酸盐前驱体和1-十二烷硫醇合成的高质量CIS核（QE = 31.7%）中。在450 nm激发下，CIS/ZnS/ZnS量子点显示出80.0%的高量子效率和559 nm的峰值波长，这与蓝色LED的主波长良好匹配。通过X射线衍射、透射电子显微镜和电感耦合等离子体发射光谱分析证实了核/壳/壳结构的形成。CIS/ZnS/ZnS强烈而宽广的黄绿色发射带有利于产生明亮的双波段白光。当将CIS/ZnS/ZnS涂覆在蓝色LED上时，制备的白光LED显示出明亮的自然白光（发光效率（η(L)） = 80.3 lm·W⁻¹，显色指数（R(a)） = 73，相关色温（T(c)） = 6140 K）。量子点白光LED封装显示出72.6%的高光转换效率。此外，CIS/ZnS/ZnS转换的白光LED在20 - 150 mA的正向偏置电流变化下表现出相对稳定的白光[色坐标（x，y） = （0.3320 - 0.3207，0.2997 - 0.2867），R(a) = 70 - 72，T(c) = 5497 - 6375 K]。
