ORGANIC AND INORGANIC ELECTROLUMINESCENT DISPLAYS INCLUDING A POROUS SILICON LAYER

为了提高有机电致发光显示器件的效率和色质，我们研究了含无机多孔硅层的有机电致发光显示器件的电学和光学特性。主要研究结果如下：1.通过调整阳极氧化电流密度和光照方式等制备条件，将多孔硅的禁带宽度控制在1.6 ~ 2.3eV之间。我们发现多孔硅作为PVK基聚合物电致发光器件的缓冲层时，对载流子通过有机层的输运过程具有很大的空穴阻挡优势。2.提出了由聚合物发光层、荧光客体掺杂剂和多孔硅层组成的新型器件结构，通过结构和材料的设计，显示了深蓝、亮绿色和纯白色电致发光。蓝、绿色和白色OLED的外量子效率和色坐标（x，y）分别为5.1%（0.15，0.09）、5.5%（0.20，0.60）和4.0%（0.33，0.33）。通过使用该方案，首次提出了一种名为“侧耦合颜色转换方法”的新的彩色面板结构，并显示了通过利用侧发射将白色效率提高两倍的可能性。总之，本研究显著提高了器件的效率，但从实用的角度来看，器件的可靠性、红色OLED的效率和多孔硅的再现性仍存在技术问题。

We investigated on electrical and optical properties in organic EL display devices including inorganic porous silicon layer in order for the improvement of efficiency and color quality. Research results are summarized as follows.1.We controlled band-gap energy of porous silicon in the range between 1.6 and 2.3eV by adjusting preparation conditions such as anodization current density and light irradiation metode. We found that the porous silicon has great advantage of hole -blocking to the carrier transport process through the organic layer when is used as a buffer layer for PVK based polymer EL devices.2.We proposed new device structure consisting of polymer emissive layer, fluorescent guest dopant and porous silicon layer, and showed the deep blue, bright green and pure white electroluminescence by designing the structure and materials. The external quantum efficiencies and color coordinates (x, y) are 5.1%' (0.15,0.09), 5.5% (0.20,0.60) and 4.0% (0.33,0.33) in blue, green and white OLEDs, respectively.3.Optical analysis was developed for the stacked layer organic EL devices on the basis of fresnel analysis and transferred matrix. By employing this program, new color panel structure named "Side-coupling color conversion method" was first proposed and showed a possibility to increase the white efficiency twice as much by utilizing a lateral emission. High efficiency beyond the theoretical limitation of transition probability was confirmedIn conclusion, efficiency of the device was significantly improved by this study, but technical problems are still remained in reliability of the device, efficiency of red OLED and reproducibility of porous silicon for the practical viewpoints.