近年來，有機發光二極體(OLED)快速的發展。主要的原因在於它具有製作上的簡易性、低驅動電壓、低秏電功率、廣視角、高亮度和高效率、超薄結構與機械可撓性等性質，因此有機發光二極體於未來幾年內是極有可能挑戰平面液晶顯示器(LCD)的市場。而現在已有幾家公司已生產單色OLED顯示器用於手機螢幕與汽車儀表板上，而下個市場上的目標則是開發全色系OLED顯示器。全色系OLED顯示器則需紅、綠、藍三色系發光材料，而開發新型藍光材料為近年來較為熱門的題材，原因在於它能轉換成其他兩種色系的發光材料。由於藍光材料的能帶(band gap)較大，擁有較高的低未配對分子軌域(LUMO)，易造成陰極電子不易躍遷，且現有的藍光材料的光色純度、穩定度不夠與生命週期短(lifetime)，這些仍是有待研究與改進的地方。另一有趣的課材則為紅光材料，主要分成聚合物材料與小分子材料，此兩種不同物性的材料皆利用微調(tuning)結構的共軛性質來造成能帶降低而獲得純光色，確易造成其光量子產率下降，使其不利於應用。 組合式化學已廣泛的應用於藥物開發與生物技術上，其平行(parallel)固相合成方法則為最為廣為使用的合成工具。組合式合成於材料的開發上，現今大多使用傳統化學合成方法來進行，這始終無法加速材料的開發。本論文則是利用組合式固相合成的方式來進行OLED紅光磷光材料的開發並進行放光波長的screening。利用我們所開投的方法，我們可以於固相合成中進行有機金屬的反應，並於樹脂(resin)進行紅光發光材料的波長分析，最後選出可行的發光材料進行device的製作。利用此方法，我們獲得其中一紅光材料具有不錯的色彩飽合度與發光效率，其結果分別為最大發光效率為20.3%與CIE值為(0666, 0.332)。 In the near future, a rapid growth is sighted in the applications of organic light-emitting devices (OLED) in diverse fields. The major reason behind such a rapid expansion is their ability to provide low-cost route for large-area light-emitting display technology. Their flexibility, low cost of fabrication and low operational voltages are some of the advantages that have attracted considerable interest of scientific as well as commercial community. Organic light-emitting diodes (OLEDs) can be used in displays to provide full viewing angle. Already the monochromatic OLEDs are being used for display panels in mobile phones and car stereos. However, to obtain the full-color display, the red, green, and blue colors with appropriate chromaticity are essential. Recently designed blue emitters are the most sought-after materials. But, due to high lowest unoccupied molecular orbital and large band gap energy, electrons migration from cathode to anode is difficult in case of blue emitters. The adequate modifications in conjugation may convert them into green or red emitters. However, the elaboration of conjugation is mostly associated with loss of quantum energy or luminescence intensity which is unfavorable for their applications in displays. Combinatorial approach includes parallel synthesis and high-throughput screening of the compounds for desired properties. We herewith report a complete combinatorial strategy, solid-phase synthesis and rapid screening, to discover luminescent organometallic complexes for applications in organic light emitting diodes (OLEDs). A library of red phosphorescent Ir-complexes has been synthesized with an efficient synthetic strategy which includes the use of unique spacers and assembling of unreported resin-bound bis-cyclometalated Ir(III) μ-chloro-bridged dimers. The combinatorial screening was developed to search for high luminescent materials from the synthesized library of the resin-bound compounds. Bright light-emitting hits can be identified through mere manual observation of the brightness and determination of emission maxima of on-bead compounds. This screening technique was validated from photophysical characteristics of leads, cleaved products and the corresponding emitters. Using this method, two hits were identified and used as dopant emitters in the fabrication of electroluminescent (EL) devices. One of these devices possesses saturated red emission with a maximum external quantum efficiency of 20.3%, current efficiency of 16.6 cd/A and CIE coordinates at x = 0.666, y = 0.332.
