短波長有機發光材料與元件

Abstract

短波長有機發光材料與元件，具有高度應用於照明燈源及全彩化顯示器上之潛力。 在本論文中，首先我們探討含嘧啶環寡聚物，其具有良好的薄膜形態穩定性，高螢光量子產率及寬能隙等特性，可作為藍光有機發光元件之發光層材料或主體材料，而據以製作之藍光有機發光元件在直流電源驅動時，可承受高電流密度，產生高亮度之藍光。 接著，我們探討三聚芴化合物，其所具有罕見之高螢光量子產率及雙極性載子傳輸特性，將其應用於藍光有機發光元件時，會因為元件結構而影響元件特性。經由雙層異質結構之元件設計，大幅地提昇元件之發光效率，未摻雜客體發光物之藍光元件具有低操作電壓及相當高的外部量子效率等特性，其所發出的藍光光色相當地純且色彩飽和。 最後，我們探討二聚芴化合物作為紫外光有機發光元件之發光層材料，由於二聚芴化合物在固態薄膜時，具有良好的形態穩定性、高螢光量子產率及良好之雙極性載子傳輸特性，搭配雙層異質結構，成功地製作出具有高外部量子效率、低操作電壓及低亮度起始電壓值之電特性的紫外光有機發光元件。

Organic light-emitting devices (OLEDs) have been the subjects of intense investigation in recent years due to their applications in displays and lighting. In all these applications, the short-wavelength emitting materials and devices with high efficiency, good color purity and thermal stability have been essential. In this thesis, we investigate of various device architectures to study the optical and electrical properties of the short-wavelength emitting materials. In the first part of the work, we employed an efficient and morphologically stable pyrimidine-containing spirobifluorene-cored oligoaryl, as a blue emitter or emitting host for blue OLEDs. These devices exhibit unique endurance for high currents, leading to a very high brightness under dc driving. In the second part of the work, we investigate various device architectures of OLEDs incorporating highly efficient blue-emitting and ambipolar carrier-transport ter(9,9-diarylfluorene)s, and their influences on device characteristics. Using the double heterostructure that provides effective double confinement on both carriers and excitons, results in a high EL external quantum efficiency, low-voltage, and very saturated blue emission without doping the emitting layer. Finally, we studied a series of UV emitter based on ambipolar carrier-transport bi(9,9-diaryfluorene)s that exhibited promising physical properties including high morphological and thermal stability, and high neat-film quantum yields for UV emission. The UV OLEDs using the double heterostructure can exhibit high EL external quantum efficiency, low device voltage, and UV emission without emissive dopants.