卤化亚铜配合物的光致发光与电致发光研究

In order to solve two current big problems, energy crisis and environment pollution, the development of display and solid state lighting technologies with high efficiency and low cost properties is highly necessary. Organic light-emitting diode (OLED) is considered as one of the most competitive technologies. So far, OLEDs using phosphorescent emissive iridium-based complexes have been achieved the highest efficiency. Unfortunately, iridium is low in natural abundance and very expensive, which restricts its commercial application. Though cheap Cu(I) complexes based OLEDs theoretically have the maximum internal quantum efficiency of 100%, most Cu(I) complexes are unstable toward sublimation and hence not amenable to the vacuum deposition methods typically used to fabricate OLEDs, few devices containing such emitters have been explored. In this project, we study cuprous halide complexes (CuX)mLn（X = I, Br, Cl; L = Ligand), to explore the controllable synthesis of materials and OLEDs, as well as to realize high efficiency conversion from electricity to light. In details, a series of ligands/hosts L will be synthesized. By in situ codeposition of the ligand/host L and CuX, amorphous films containing thermal unstable complex (CuX)mLn with different chemical structures and emission colors could be fabricated, hence OLEDs with high efficiencies and tuned emission colors. This study would provide a basis for exploring low-cost, new type, high efficiency materials as well as OLEDs.

为节约能源和减少环境污染，研发高效率、低成本的新一代显示和固态光源技术势在必行，其中有机发光二极管(OLED)最具竞争潜力。目前，铱配合物OLED虽然具有最高的发光效率，但是铱在自然界中含量低、价格贵，严重制约了其商业化应用。廉价的Cu(I)配合物OLED尽管在理论上也具有100%的最大内量子效率，但是大多数Cu(I)配合物热稳定性差，无法通过传统的真空蒸镀方法制备器件，限制了其作为新型OLED材料的研究。本项目拟以卤化亚铜配合物(CuX)mLn（X = I, Br, Cl；L = 配体）为研究对象，探讨材料和器件的可控合成及电光的高效转换。设计、合成一系列有机小分子配体/主体材料，针对热稳定性差的配合物，发展共蒸原位反应技术，制备多种结构和发光颜色的(CuX)mLn配合物和高效率、全彩色及白光Cu(I)配合物OLED，为低成本、新型、高效OLED材料与器件的研制奠定理论和技术基础。

有机发光二极管(OLEDs)由于具有能耗低、柔性等优点，在新一代显示和固态照明领域具有广阔的应用前景。目前，铱配合物发光OLEDs虽然具有最高的发光效率，但是铱在自然界中含量低、价格贵，严重制约了OLEDs商业化应用。低成本的Cu(I)配合物发光OLEDs尽管在理论上也具有100%的最大内量子效率，但大多数Cu(I)配合物热稳定性差，无法通过传统的真空热蒸镀方法制备OLEDs器件，限制了其作为新型OLEDs发光材料的研究。鉴于此，本项目发展了碘化亚铜（CuI）配合物的共蒸原位反应技术，即在真空腔体内同时蒸镀CuI和有机小分子配体/主体材料，原位生成CuI配合物掺杂的发光薄膜，该技术集合了热蒸镀过程与原位反应，尤其适用于制备加热易分解的配合物薄膜，为热稳定性差的CuI配合物在OLEDs中的应用提供了一种全新的思路。此外，该技术不仅极大地拓展了CuI配合物的选择范围，还显著降低了配合物合成及纯化的成本。通过系统地设计、合成具有不同电子结构、分子轨道能级、三重态能级、载流子传输性、配位数、空间位阻等因素的有机小分子配体/主体材料，我们制备出外量子效率高达15.7%的CuI配合物OLEDs，与相同结构铱配合物OLEDs相当；制备出发光颜色丰富，包括绿光、黄光、橙光、红光及白光OLEDs。通过对这些结果的分析，我们揭示了高效、全彩色CuI配合物掺杂薄膜与小分子配体/主体材料结构的构效关系；明确了CuI配合物掺杂薄膜的结构、光学、电学性能的有效调控机制；阐明了制约CuI配合物发光OLEDs性能的关键因素，为低成本、高效率、全彩色及白光CuI配合物OLED 的可控制备提供了理论和技术基础。