有机微腔绿色发光二极管

Organic Microcavity Green Color Light Emitting Diode

光学微腔是指尺寸在光波长量级的光学微型谐振腔。微腔结构可以使腔内物质和光场的相互作用与体材料相比发生很大变化,出现了自发辐射谱线窄化和增强等腔效应。利用这些腔效应,可以改善有机发光器件的性能。采用微腔结构,优化设计并研制了有机微腔绿色发光二极管,器件结构为Glass/DBR/ITO/NPB/Alq∶Rubrene/Alq/MgAg,获得了最大亮度40100 cd/m2、最大发光效率为6.44 cd/A、半峰全宽为28 nm的纯绿色有机微腔电致发光器件。而与之比较的无腔器件最大亮度为22580 cd/m2、最大发光效率为2.98 cd/A、半峰全宽为120 nm。相同电流密度下微腔电致发光谱的峰值发射强度是无腔器件的4.2倍。结果表明将微腔结构引入有机电致发光器件中,不但改善了发光的色纯度,而且使器件的发光效率和亮度都得到明显增强。

An optical microcavity is a structure with at least one dimension on the order of an optical wavelength. The interaction between material and light within microcavity was changed greatly compared with the condition of free space. Cavity effects such as spectral narrowing and intensity enhancement of spontaneous emission have been observed. These effects can be used to improve the electroluminesence （EL） performances of organic light emitting device （OLED）. The microcavity structure of green light OLED was optimized. The device was fabricated and studied with a structure of Glass/DBR/ITO/NPB/Alq.-Rubrene/Alq/MgAg. The maximum luminance of 40100 cd/ m^2 , maximum luminous efficiency of 6.44 cd/A, and a full width at half maximum （FWHM）of 28nm were obtained in microcavity OLED, whereas the maximum luminance of a noncavity device is 22580 cd/m^2 , maximum luminous efficiency 2.98 cd/A, and FWHM 120 nm. The EL peak intensity of the microcavity device is 4.2 times stronger than that of noncavity device of the same current density. It shows that introduction of microcavity into OLED improves not only the color purity, but also the luminous efficiency and luminance of the device.