可用於增進有機發光元件性能之光學結構研究

Abstract

在本論文中，我們研究數種新型結構並用以增進有機發光元件之性能。首先，我們提出對電極材料不敏感的電洞注入架構以及電子注入架構。這些架構可用於提升有機發光元件的電特性。接著，以這些載子注入架構為基礎形式連接單元，並將之用於白光堆疊串接式元件，使該元件具有良好的光電特性。 接下來，採用具波長選擇作用的反射鏡面作為電極，並以此來調變白光元件的發光頻譜，我們實現了在紅光、綠光和藍光波段具有陡峭發光峰的三發光峰白光有機發光元件。其頻譜與典型彩色濾光片的穿透帶有較佳之匹配，可產生較飽和的三原色，將色域範圍大幅提高至87%。依類似之概念，我們設計另一種波長選擇性反射鏡面來增進藍光有機發光元件發光的色彩飽和度。透過仔細地設計該鏡面的結構與適當地選擇發光區相對於該鏡面的距離，以苝為摻雜物之藍光元件發光的色彩飽和度可被大幅改善，其CIEx,y色度座標為(0.151, 0.092)。 最後，我們利用嚴謹的電磁學模型分析輸出端鏡面的反射率對光學微共振腔有機發光元件發光特性之影響，並以實驗結果驗證之。其中輸出端鏡面反射率之調變乃是藉由在薄金屬上沈積不同厚度的介電層來達成。

In this thesis, we investigate various novel architectures for enhancing performances of organic light-emitting devices (OLEDs). First, we propose hole-injection and electron-injection schemes that are insensitive to electrode materials. Such schemes can be used to improve electrical characteristics of OLEDs. Then, an effective connecting structure based on such carrier injection schemes is used in tandem white-emitting devices, giving superior electrical and optical performances. Next, by employing the wavelength-selective mirror as the cathode and the reflecting mirror to reshape the spectra of devices, we realize the three-peak white-emitting OLEDs that show sharp peaks at RGB wavelengths and have spectra matching better with transmission spectra of typical color filters and thus give much enhanced color gamuts of 87%. Based on quite similar concept, another wavelength-selective mirror is designed to enhance the color saturation of blue OLEDs. Through carefully designing the wavelength-selective mirror and choosing suitable emitter-to-mirror distance, the CIE coordinates of Perylene-based blue devices can achieve (0.151, 0.092), which is very close to the NTSC recommendations. Finally, we investigated theoretically and experimentally the influences of the reflectance of the exit mirror on the emission characteristics of microcavity OLEDs having resonant wavelength set at the peak wavelength of the intrinsic emission by adjusting the thickness of dielectric capping layer.