Science and Function of Organic Amorphous Materials-An Approach from Precise Analysis of Static and Dynamic Structures-

The purpose of this project is to establish solid-state NMR methodology which enables us the detailed analysis of static and dynamic structures of organic amorphous materials. In this study, the structure analysis of organic low-molecular-weight materials and polymers including synthetic and natural rubbers was performed. Among the series of researches, we especially focused on the analysis of materials for organic light-emitting diodes (OLEDs). For a light-emitting OLED material, a clear relationship was obtained between the light-emitting properties and the isomeric states. Since the isomeric states of Alga are difficult by X-ray diffraction experiments, the results obtained in this study clearly show the validity of the structure analysis by solid-state NMR On the basis of the relationship, OLEDs were fabricated from α-Alq3, δ-Alq3, and the mixture powders of α-, γ-, and δ-Alq3 It was found that the devices fabricated from δ-Alq3 and the mixture powders exhibit higher luminescence compared to those from standard α-Alq3. For a hole-transport OLED material, the intermolecular distance was determined by solid-state NMR with a supercycle R26411 pulse sequence. This is a first example, which experimentally determines the hopping distance for the carrier transport of the OLED material.