Research On Synthesis And Performance Of Organic Small Molecular Light-emitting Materials Based On Carbazole

OLED (Organic Light-Emitting Diodes) is a new kind of flat panel display. Due to its extraordinary properties, for example, low energy consumption, self-illumination, solid-state lighting, high brightness, wide view angle, flexibility, OLED has become one of research hotspot in the world.Carbazole possesses special rigid plane structure, large conjugate system and good intermolecular electron transition ability. So, carbazole is a kind of very important organic electroluminescent material. In addition, it exhibits excellent photoelectric properties, which is facile to introduce funcitonal groups in its 3,6,9 bits. Carbazole is often utilized as foundation in designing and synthesizing photoelectric functional organic molecules. And, research on carbazole derivatives has gained more attention in OELD research area now.Introducing long conjugated chain, elcrton-donating groups, electron-drawing groups or rigid conjugated plane can effectively improve luminous performance of organic electroluminescent materials. For gaining a kind of light-emitting materials with rigid conjugate flat plane, people usually adopt molecules with rigid conjugated plane and connect electron donors or electron acceptors in its skeleton by conjugated bridge. Besides, introduction of long alkyl chain can effectively block intramolecular electronic transition and improve solubility.In this paper, carbazole was used as base in its molecules. Through various reactions, different functional groups were introduced in its 3,6,9 bits, respectively, and five kinds of organic electroluminescent materials were synthesized and were named as CB,CCN,CBQ,CBBQ,CBCN. Their structures were characterized by elemental analysis, IR spectra and 1HNMR spectra. For discussing luminous properties, their ultraviolet-visible absorption spectra and fluorescence spectra were measured and analyzed. In addition, films of above five kinds of organic electroluminescent materials were prepared by spin-coating, which were observed by AFM in order to characterize film formability.The experimental results have shown as follows:(1) The five materials can emit different colors of light. The emission spectra were that:CB:379nm, CBQ:407nm, CBBQ:420nm, CBCN:497nm, CCN:612nm.(2) Alkyl chain can effectively hinder intra molecular electronic transition between carbazole and other groups and can improve solubility.(3) It can also indicated that introduction functional groups in carbazole induces remarkable variation of fluorescence spectra, that is, structure modification of carbazole can change its band gap and realize emitting different-colors light and effective controling light-emitting colors. (4) In addition, the five organic small molecule light-emitting materials based on carbazole exhibit excellent solubility and film formability, which can be made into OLED by wet processes.