Small Organic Molecule Semiconductor Materials Sublimation Purification Process Improvements

Organic Electroluminescent devices is light-emitting phenomenon arising from luminescent materials in which electricity is transformed into light when turned appropriate voltage on. Compared with the normal display devices, It has a higher luminous efficiency, lower driving voltage, wider visual angle, wider range of material selection, simpler production process, so it has been Known as the new generation of flat panel display, and causing more and more attention. But some of the shortcomings such as:shorter device working life, unbalanced carrier injection, lower color light-emitting efficiency, higher production costs of the device, lower yield and other reasons, limit the commercial development of OLED. Therefore, it is a great significance to Solution the lifetime,efficiency and production cost of the devices by improving the purity of the organic small molecule material. In this paper,we focuses on synthesis of high transmission performance of carrier transporting materials, improve the purity and the recovery of the material after sublimation purification.In the frist part of the paper,we synthetic high-performance hole transport materials NPB and electron transport material Alq, selecting the appropriate reactant, catalyst and post-treatment process, reduces the conditions in Alq Synthesis process,long reaction time in NPB Synthesis process,we get the high purity crude materials,whose purity get 98.5%and 98.7%. we purify the crude materials by adding Ar gas, double zone sublimation method,prepared to meet the light-emitting devices on the material purity requirements, The sublimation method can effectively improve the purity of the material, improve the rate of sublimation and distillation purification equipment to reduce the production cost. Finally, we used the materials of different number sublimation made the OLED devices, compared the performance of the device. The results showed that the improvement of material purity,reduce the impurities on the carrier and exciton been completed, reducing the luminescence quenching centers, improved device performance.In the second part of t he paper, we improved the traditional sublimation purification equipment by increased baffle in the glass tube to increase the collision of the material after sublimation, comparing the performance and materials recovery with different baffle device. The results show that increase the the baffle in High temperature zone, the smaller the baffle opening area, the higher material purity; In the case of the same opening area, reduce the size of individual openings, Increase the number of openings, Increasing the size of the entrance is on the gas can improve the purity of the material. Under the same baffle, Increased gas flow also can improve the purity of the material. Increase the baffle at low temperatures has little effect on the total recovery of the material, but the high purity materials deposite more concentrated, so increased the recovery of the high purity materials.