Department of Electronic Engineering, Institute for Wearable Convergence Electronics, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
Semicon Light Co., Ltd., 49 Wongomae-ro 2beon-gil, Giheung-gu, Yongin-si, Gyeonggi-do 446-901, Republic of Korea.
Sci Rep. 2017 Feb 9;7:42348. doi: 10.1038/srep42348.
The commercially available white-light-emitting diodes (WLEDs) are made with a combination of blue LEDs and yellow phosphors. These types of WLEDs lack certain properties which make them meagerly applicable for general illumination and flat panel displays. The solution for such problem is to use near-ultraviolet (NUV) chips as an excitation source because of their high excitation efficiency and good spectral distribution. Therefore, there is an active search for new phosphor materials which can be effectively excited within the NUV wavelength range (350-420 nm). In this work, novel rare-earth free self-luminescent CaKZn(VO) phosphors were synthesized by a citrate assisted sol-gel method at low calcination temperatures. Optical properties, internal quantum efficiency and thermal stability as well as morphology and crystal structure of CaKZn(VO) phosphors for their application to NUV-based WLEDs were studied. The crystal structure and phase formation were confirmed with XRD patterns and Rietveld refinement. The optical properties of these phosphor materials which can change the NUV excitation into visible yellow-green emissions were studied. The synthesized phosphors were then coated onto the surface of a NUV chip along with a blue phosphor (LiCaPO:Eu) to get brighter WLEDs with a color rendering index of 94.8 and a correlated color temperature of 8549 K.
市售的白光发光二极管（WLED）是由蓝色发光二极管和黄色荧光粉组合而成。这些类型的 WLED 缺乏某些特性，使得它们在一般照明和平板显示器方面的应用有限。解决这个问题的方法是使用近紫外（NUV）芯片作为激发源，因为它们具有高激发效率和良好的光谱分布。因此，人们积极寻找新的荧光粉材料，这些材料可以在 NUV 波长范围内（350-420nm）有效激发。在这项工作中，通过柠檬酸辅助溶胶-凝胶法在低温下合成了新型的无稀土自发光 CaKZn（VO）荧光粉。研究了 CaKZn（VO）荧光粉在近紫外基白光 LED 中的应用，包括光学性能、内量子效率和热稳定性，以及形貌和晶体结构。通过 XRD 图谱和 Rietveld 精修证实了晶体结构和相形成。研究了这些荧光粉材料的光学性质，它们可以将 NUV 激发转化为可见的黄绿光发射。然后，将合成的荧光粉涂覆在 NUV 芯片表面，再加上蓝色荧光粉（LiCaPO：Eu），得到显色指数为 94.8、相关色温为 8549K 的更亮的 WLED。
