Design of Phosphorescent Organic Light Emitting Diodes (OLED) Host Materials Based on Carbazole: Quantum Chemistry Study on Carrier Transport Properties of Oxazole Derivatives

摘要

Organic Light Emitting Diodes (OLEDs), as lighting materials, have great application potential. Compared with fluorescent OLEDs, phosphorescent OLED devices can produce higher luminous efficiency, which is favored by many researchers. Among them, the key material of OLED is an important factor affecting the performance of this kind of device. In this study, the carbazole group and the 1,2,4-Triazole group with high hole transport properties were used as research materials, and four bipolar main materials of Triazole-carbazole group were prepared by mixed reaction under high temperature and catalyst conditions. One of the materials (4PTBB) was selected as carbazole derivative, and the Density Functional Theory (DFT) was introduced to study the carrier transport properties of the derivatives in quantum chemistry. During the experiment, the physicochemical properties of the four Triazole-carbazole bipolar host materials were analyzed. These new materials exhibited good thermal stability (Td: 418-448 degree), high glass transition temperature (Tg: 127-149 degrees C) and high triplet energy level (E-T: 2.38 eV-2.78 eV); and the electron mobility of 4PTBB (5.77x10(-2) cm(2).V-1.s(-1)) was two orders of magnitude higher than hole mobility (5.89x10(-4) cm(2).V-1.s(-1)). The above results indicated that the Triazole-carbazole bipolar host material has good thermal stability and good electron transport performance, and it can be used for phosphorescent OLED devices to exhibit better performance.