Design、Synthesis And Optoelectronic Properties Of Spirofluorene Compounds For Blue Light Emission

Organic Light Emitting Diodes(OLED) are self-luminous, high-brightness, simple structure, low driving voltage, wide viewing angle, rich color,fast response time,luminescence performance from the ambient temperature limits, anti-shock and the advantages can be curled.OLED is recognized as the most promising next-generation display technology. In the red, green and blue light-emitting display materials, red and green light-emitting materials have been met OELD needs, but highly efficient and stable blue light-emitting material is still small,that it hindered the full-color OLED, and the pace of industrialization of white light devices. Blue light-emitting materials include polymers and small molecular compounds, fluorenone compounds is as rigid planar structure, has good fluorescence properties, so the framework of structural materials with spirofluorene has high quantum efficiency, applied to the OELD display materials it can improve the thermal stability, shape stability and the stability of carrier mobility, it also can improve solubility of blue light-emitting materials.So spirofluorene is a better blue light-emitting materials. Therefore,inrecent years, research of spirofluorene as blue light-emitting materials is hot and grows fast.Our work including the following aspects:1. 2,7– dibromo-spiro[fiuorene -7,9’-benzofluorene] as basic blue light-emitting materials has been synthesized efficiently by Suzuki coupling reaction, the addition reaction of carbonyl with lithium reagents. By C-N coupling reaction,we successful add diphenylamino group and carbazolyl group on the spiro[fiuorene -7,9’-benzofluorene];by Suzuki(C-C)coupling we successful add two aromatic biphenyl and naphthalene group on the spiro[fiuorene -7,9’-benzofluorene]. Target compounds were determined by 1HNMR、MS、IR and elemental analysis.2. Their optical properties were characterized by UV、PL,their thermal properties were determined by DSC and TGA,their HOMO、LUMO energy were calculated by CV. The results show that :(1)All of the synthesized compounds emit strong blue fluorescence and have high fluorescence quantum yield;(2) The compounds possess high thermal stabilities, Tg are more than 240℃, Td more than 400℃,with them we can prepare long-life Blu-ray device;(3) The synthesized compounds have high HOMO level energy and low LUMO level energy, and it is in the interest of hole and electron transport;(4) The synthesized compounds have good solubility,which is advantaged for OLED device fabrication using spin-coating method.