MgF_2改性Alq_3纳米复合材料的制备及其对OLED抗老化性能的提高

MgF_2 Modified Alq_3 Nanocomposite: Synthesis and Improvement of Anti-Aging Performance of OLED

提高有机电致发光器件(OLED)的稳定性和寿命是其市场化应用中需要解决的关键问题.本文从提高发光材料自身的稳定性出发,以Mg(CF3COO)2–x(CH3COO)x溶胶为前驱体,将其与8-羟基喹啉铝(Alq3)混合浓缩成糊状后,300°C真空烧结,经过MgF2的生成和Alq3的相变后,形成了一系列Mg含量不同的具有超结构ε相的纳米复合材料Alq3-MgF2.研究结果表明,相比于纯Alq3,Alq3-MgF2纳米复合材料制备的OLED可以很好地保持Alq3的发光特性,同时,其抗老化性能得到显著提高.特别是,Mg(CH3COO)2投料量为Alq3的5%(摩尔分数)时,所得Alq3-MgF2纳米复合材料制备的器件抗老化性能最优,在空气中老化72 h,最大发光亮度仍保持在起始值的93.5%;而Alq3制备的OLED在空气中老化24 h后基本失活.

From the viewpoint of practical application, enhancing the stability and lifetime of organic lightemitting diodes（OLED） is a goal of research. A MgF2 modified tris（8-hydroxyquinoline）-aluminum（Alq3） hybrid superstructure was realized by collosol infiltration of a Mg（CF3COO）2–x（CH3COO）x precursor onto Alq3. Alq3 was well-dispersed in a large amount of Mg（CF3COO）2–x（CH3COO）x gel precursor solution, and after concentration a well-dispersed composite paste was produced. By heating the paste to 300 °C, Alq3 transformed to the superstructured ε-phase, and MgF2 homogeneously incorporated because of good gel precursor infiltration and in situ deposition. The MgF2-modified Alq3 nanocomposite with superstructure has the same electroluminescence（EL） spectrum as Alq3, with a dramatic improvement of the anti-aging performance of the OLED compared with Alq3 because of the uniform assembly and well-defined structure. The effect of the amount of Mg（CH3COO）2 reactant on the OLED device anti-aging performance was investigated. The results showed that for the Alq3-MgF2 nanocomposite with 5%（molar fraction） of the Mg（CH3COO）2 reactant, the luminance remained at the initial state of 93.5% after aging for 72 h in air. However, the luminance of the Alq3-based OLED almost disappeared after aging for 24 h under the same conditions. This work on inorganic material modified luminescent materials makes significant progress towards stable OLED.