基于混合量子点的颜色可调QLED器件性能及其白光应用

Color-tunable QLED Based on Mixed Quantum Dots and Its White-light Application

采用红色、绿色混合量子点作为发光层,制备了结构为ITO/PEDOT∶PSS/TFB/Mixed-QDs/ZnO/Ag的颜色可调量子点发光二极管(QLED)器件,研究了QLED器件的电致发光光谱。实验结果表明,混合QLED器件具有明显的颜色可调特性。随着外加电压增大,混合QLED器件呈现出从暗红色到橙黄色再到耀眼的黄绿色的颜色变化。其开启电压为2.0 V,最大亮度可达到6×10^(4) cd/m^(2);且器件在31934 cd/m^(2)亮度下实现了21 cd/A的最大电流效率和7.5%的最大外量子效率。作为应用展示,本文将颜色可调的混合QLED器件与氮化镓基蓝光LED相结合制备了白光LED,相关色温可从3568 K(暖白光)调至10269 K(冷白光),且显色指数不低于70,在照明应用中具有广阔的应用前景。

A color tunable quantum-dot light emitting diode(QLED)with the structure of ITO/PEDOT∶PSS/TFB/Mixed-QDs/ZnO/Ag was fabricated by using red and green mixed quantum dots as the light-emitting layer,and the electroluminescence spectrum of QLED device was studied.The experimental results show that the QLED device has significant color tunability.With the increase of applied voltage,the QLED device presents a color change from dark red to orange and then to dazzling yellow-green.The QLED device exhibits a turn-on voltage of 2.0 V and the maximum brightness can reach 6×10^(4) cd/m^(2).What's more,the device achieves a maximum current efficiency of 21 cd/A and a maximum external quantum efficiency of 7.5%at 31934 cd/m^(2).As an application demonstration,we further combine the color tunable QLED device with GaN-based blue LED to prepare a white light emission.The results show that the color temperature of white light emission can be tuned from 3568 K(warm white)to 10269 K(cold white)and color rendering index is not less than 70,exhibiting great prospects in the application of lighting.