高效顶发射量子点发光二极管的结构和性能研究

量子点发光二极管 （ QLED） 由于具有色纯度高、 高效率和溶液制
备等优点，被认为最有希望成为下一代显示技术。经过多年来研究人员
的共同努力， QLED 效率以及稳定性都得到了极大的提升。但是大多数
报道的 QLED 都是基于底发射结构。 然而，对于显示应用来说，顶发射
量子点发光二极管（ TQLED）可以获得更高的显示器的开口率、效率和
颜色饱和度。 目前顶发射结构大都采用半透明金属 作为顶电极的强微腔
结构，该结构存在着严重的角依赖发射和无法实现白光出射的问题。此
外，金属顶电极的吸收和表面等离子体激元效应也会降低器件的发射效
率。
为了解决上述问题， 本文首先，采用铟锌氧化物（ IZO）代替传统金
属作为顶电极，开发出了高效稳定的 TQLED。由于 IZO 的高透过率，器件
的微腔效应得到了削弱， 光谱的角度稳定性得到了提升。 其次， 在 IZO 电
极上引入纳米球散射层作为出光结构，有效的实现了对器件内部波导模式
的光萃取，大幅提升了相应器件的出光效率。所制备的出光红色、绿色和
蓝色器件外量子效率(EQE)， 分别实现了 35%、 50%和 133%的提升幅度，
相应器件的 EQE 最大值分别为 32.5%、 19.2%和 10.3%。其中红色 TQLED
的 EQE 刷新了目前顶发射红光器件的记录。 此外， 纳米球的散射作用极大
的提升了器件的发光强度和光谱的角度稳定性，实现了 0 度-75 度观测角内
光谱的零偏移。
最后，将纳米球散射层应用于顶发射混合白光器件，很好的将被微腔
效应调制的白光光谱还原出来，实现了均衡的白光出射（ 0.292， 0.359）。
相比于常规白光 QLED，基于微球的 QLED 器件具有更优异的器件性能。
最终获得亮度为 47210 cd/m2，电流效率为 19.1 cd/A， EQE 为 8.06%的顶
发射白光量子点发光二极管，完成了对顶发射白光领域的初步探索。
 

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