基于ZnS增透膜的顶发射白光有机发光二极管

顶发射白光有机发光二极管(TEWOLED)在白光照明和全彩显示中有着良好的应用前景, 克服顶发射器件中的微腔效应是制备光电性能良好的TEWOLED的前提. 使用具有高折射率的ZnS作为增透膜改善金属阴极在蓝光波段的透射率,降低其反射性, 从而有效抑制了微腔的影响.同时利用转移矩阵理论和宽角干涉方法分别对阴极结构和 蓝光发光层位置进行了优化,最终获得了高效、色纯度良好、色度随视角变化小的TEWOLED. 最高亮度和效率分别达到9213 cd/m²和3 cd/A,色坐标位于白光区且接近白光等能点, 同时具有良好的视角稳定性,在0°---60°范围内色坐标仅变化(0.02, 0).

Top-emitting white organic light-emitting diodes based on a ZnS light outcoupling layer

Top-emitting white organic light-emitting diode (TEWOLED) has potential applications in lighting and full color displays. Microcavity effect in TEWOLED restrains the realization of the white emission with excellent optical and electric performances. In this paper, a ZnS film with a high refractive index used as a light outcoupling layer is introduced into the metal cathode to enhance its transmittivity to a maximal value in the blue light wavelength region. In addition, transfer matrix theory is utilized to optimize the thicknesses of the cathode and the ZnS outcoupling layer and the wide-angle interference is used to design the position of the blue emission layer inside the organic light-emitting diode. Based on the above work, the white light with relatively high luminous efficiency, good color purity, and small CIE coordinate change is acquired. The corresponding luminance and current efficicency are 9213 cd/m² and 3 cd/A, respectively. The CIE coordinates belong to the white emission and are near the white light equal-energy point. The white emission also shows stable spectra with respect to the observation angle, with a limited CIE coordinate change of (0.02, 0) for a large observation angle change from 0° to 60°.