Surface Modification And Application Of8-Hydroxyquinoline Aluminum In OLED

8-hydroxyquinoline aluminum (Alq3) is an important electron injection and light-emitting material in the Organic Light Emitting Diode (OLED). It has the advantages of low cost, convenience for preparation, high electron affinity (EA≈3.0eV), high ionization energies (Ip≈5.95eV), good thermal stability (glass transition temperature of approximately172℃), high electron conductivity (10-5cm2·V-1·S-1), and high fluorescencequantum efficiency (32%), etc.. Therefore, the surface modification of Alq3achievd by improving its insulation against oxygen and moisture has important practical significance to improve the device lifetime.Based on small organic molecules electroluminescent light-emitting materials and inorganic phosphor coating methods, Alq3has been selected to improve the coating effect by choosing two different modified materials and optimizing the experimental schemes in the paper. In the end its aim to obtain the modified products with even coatings and good performance. The main work and conclusions of this paper are as follows:First of all, in the paper the modified material of MgF2and sol-gel method has been selected. Alq3@MgF2is obtained after Alq3is coated with a layer of Mg (CF3COO)2and then sintered at300℃vacuum environment. In the modification of Alq3by MgF2, a series of different molar content of Alq3@MgF2, have been prepared by changing the feeding ratio of MgF2with Alq3. The modification effects of Alq3@MgF2has been characterized by its surface morphology, optical properties, and especially the device performance. And in the end, when the molar content ratio is5%, the optimal modified material of Alq3@MgF2has been obtained.Secondly, on the basis of early work in the laboratory, the inorganic semiconductor material SiO2has been selected as the modified material. By optimizing the process, a layer of SiO2film deposited on Alq3by Tetraethyl Orthosilicate (TEOS) under the conditions of neutral hydrolysis has been explored. Although no uniform surface coating materials have been obtained, the performance and especially the life of device has been greatly improved compared to the early work.Finally, we proposed one pot synthesis of Alq3@SiO2. With the silicon source of TEOS and the alkaline hydrolysis catalyst and bridging agent of triethylamine, the Alq3generates and in the process, TEOS is hydrolyzed on its surface. The preparation of Alq3@SiO2structure has been successfully realized by the one-pot prepared method. By changing the feed ratio of TEOS and8-hydroxy quinoline (8-Hq), the Alq3@SiO2is the most even, smooth, and of optimal performance as the ratio is1:3. In addition, The prepared principle of Alq3@SiO2can be assigned to the plausible Cage Effect of Et3N embraced Lewis acid Alq3, and a further Et3N catalytic hydrolysis of TEOS to produce SiO2on the surface of formed Alq3.