Design, Synthesis And Characterization On Novel Organic Light Emitting Materials Containing N-heterocycles

When comparing to traditional inorganic electroluminescent material, organic electroluminescent devices(OLED) have more advantages. With decades of development, the synthesis of materials and the improvement of device properties still attract much attention although OLED has been applied in the display field to a certain scale. In addition, considerable attention has been paid to ?uorescent methods for the detection of metal ions because of their apparent advantages, such as low cost, operational simplicity, high sensitivity and selectivity, over other methods. In this dissertation, a series of compounds with diaryl 2-(pyridin-2-yl)oxazole or spiro fluorene skeleton have been synthesized and studied. Moreover, we have also designed and synthesized novel fluorescent sensors based on triaryl 1H-imidazo[4,5-b]pyrazine. The property for the detection of metal ions has been systematicaly studied. This dissertation could be divided into five parts:Firstly, we synthesized novel dipolar hosts for red phosphorescent OLED device. Based on the skeleton of diaryl 2-(pyridin-2-yl)oxazole, we introduced diphenylamine and carbazole into the para-position of the phenyl group. The properties of the hosts were studied which revealed that they possessed good thermal stability. The OLED devices based on the hosts were fabricated and they displayed well luminescent properties with low starting voltage and work voltage.Secondly, we changed the diphenylamine group with N-phenyl-2-naphthylamine to study the properties. The thermal stability became better. The expansion of conjugation system made a contribution to its hole transporting capability. In addition, the influence of different substituted positions on the conjugation scale and spatial structure had been examined as well.Thirdly, we modified the diaryl 2-(pyridin-2-yl)oxazole core with different electron donor in different sites of the phenyl group. We found that these compounds exhibited high ?uorescent intensity in solution(393-513 nm) and amorphous solid ?lm(400-500 nm) with large Stokes shifts(75-170 nm) which will prevent self-quenching through energy transfer and suppress emission in the solid state effectively.Forthly, we desighed and synthesized novel dipolar hosts with the spiro fluorene as the bridge to separate the electron donor group and acceptor group. With the structural characteristics of spirofluorene, the conjuction degree would be restricted and the intramolecular energy transfer would be suppressed as well. The high triple energy level(2.55 eV) will make contribution to the energy transfer from the host to the guest in order to improve the device properties.Finally, a series of novel fluorescent sensors based on triaryl 1H-imidazo[4,5-b]pyrazine for Pd2+/Pd0 was designed and synthesized. Fluorescence quenching occurred in the present of palladium species and they displayed a high selectivity and anti-interference. Hence, they were expected for the potential applications in human health and environmental protection.