I. Studies on the efficient organic reactions based upon palladium nanocrystals II. Design and synthesis of novel blue phosphorescent host materials for organic light-emitting diode application

Abstract

II. Design and synthesis of novel blue phosphorescent host materials for organic light-emitting diode application Organic light-emitting diode (OLED) is considered next generation technology for lighting and panel displays because of their full-color emission, low driving voltages, rapid responses, low power consumptions and high contrasts. OLED also has self-luminescent capability, not needing extra backlight. Devices based on the OLEDs can be as thin as 1 mm, much thinner than that of the Liquid Crystal Display (LCD), which has been the major display technology so far. Furthermore, OLEDs have simple manufacturing process and could be implemented as portable and/or flexible display. However, even with all the advantageous features of the OLED, blue phosphorescence is still under development and further progress on the materials development for high triplet energy charge transport is in dire need. For commercialization, new design and synthesis of stable and efficient blue phosphorescence materials are needed. The presently available materials do not have enough thermal and morphological stability and quantum efficiency. Therefore, novel host materials are needed to satisfy the required specifications. In this study, we designed novel compounds for blue phosphorescent host materials, which exhibit high triplet energy level, high electron/hole transportation property and high mobility. The main goal is development of new types of bipolar host materials, which have both electron donor and acceptor in a single molecule. Totally 29 new compounds were synthesized and 24 compounds were evaluated as host materials. Some of these compounds showed superior luminous and power efficiencies, as well as the deep blue color in CIE coordinates, compared to existing OLED materials.