高温固相法制备ZnO∶Zn绿色荧光粉及其在近紫外LEDs中的应用研究

Preparation of ZnO∶Zn Green Phosphors via Sintering Temperatures with Solid State Reaction and Their Application in Near-UV LEDs

采用高温固相法在温度900~1 100℃,时间3h的条件下制备出系列ZnO∶Zn荧光粉样品,并进行了封装应用研究。利用X射线衍射分析(XRD)、场发射扫描电子显微镜(FESEM)、荧光分光光度计(PL)和可见光光谱分析系统等手段对样品分别进行了表征分析。研究结果表明:所制备的荧光粉样品均具有ZnO晶型的六方纤锌矿结构,样品可以有效地被近紫外光激发,所发射的绿光光谱具有宽谱发射特征,峰位于502nm归属于氧空位发射,同时940℃条件下制备的荧光粉样品具有最高的发光强度。结合近紫外LED芯片和RGB荧光粉分别制备出绿光LED和白光LED,其中绿光LED在不同驱动电流(250~500mA)泵浦下表现出稳定的光谱发射特性,发射光谱谱型和色坐标基本未变,发射强度随电流升高而增加,所制备的白光LED在色温3 212K时,显色指数达到94.1,发光效率为85.6lm·W-1(@300mA,9.3V),在(250~500mA)驱动电流泵浦下同时也表现出稳定的光谱发射特性,所制备的ZnO∶Zn绿色荧光粉对于制备高显色、高品质近紫外白光LED具有潜在的应用价值。

In this paper,Zinc oxide phosphors(ZnO∶Zn)were prepared at a variety of sintering temperatures with solid state reaction.In addition,the annealing was done at 900~1 000℃for 3 h.The characterization of the samples was done by different techniques such asX-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),photoluminescence(PL)spectra and visible spectrum analysis system,respectively.The results indicate that all samples are in agreement with the hexagonalwurtzite structure of the ZnO phase.The phosphors can be effectively excitedby near-UV and emit the broad green emission band with the peak located at 502nm which was attributed to oxygen vacancies.Samples sintered at 940℃exhibitthe brightest.In addition,the green and white LED devices were fabricated with the green and RGB phosphors,respectively.The results indicate that the green LED show stable spectral emission under different driving currents(250~500 mA),the emission spectra and color coordinates are basically unchanged,and the emission intensity increases with the increasing of current,the packaged white LED with the CCT 3 212 K,Ra94.1 and luminous efficiency reach 85.6 lm·W-1(@300 mA,9.3 V)which also show stable spectral emission under different driving currents(250~500 mA).The ZnO∶Zn green phosphor prepared in this paper has potential application value in the preparation of high color rendering and high quality white light LED.