Synthesis And Properties Of Novel Organic Light-emitting Materials Based On Phenylpyrimidine

With the rapid development of novel display industry in recent years,the output of OLED devices has been in the forefront of the world,but there are still some problems,such as weak supporting ability of industrial chain and low added value of products.Among them,the problems of key materials and production equipment need to be solved urgently.This also makes the research and development of organic light-emiiting materials,which is the core part of the device,become the focus of attention.Red,green and blue organic light-emitting materials are essential for display devices.Compared with mature red and green light materials,the development of blue light-emitting materials is relatively slow.Low cost,high color purity and stable dark blue light materials are even rarer.Based on the design idea of D-?-A bipolar molecules,a series of organic small molecule blue fluorescent materials 2PQ-PPC,4PQ-PPC and 24PQ-PPC were designed and synthesized by using quinazolin and its derivatives as electron receptor group,carbazole unit as electron donor group and benzene ring as bridge group.The molecular composition of the compound was determined by nuclear magnetism and hydrogen spectroscopy,and many optical and electrical properties of the material were determined by theoretical simulation,absorption and emission spectra and CV curves.TGA and DSC results also show that materials have good thermal stability and meet the requirements of emitting layer materials.Based on three kinds of materials,OLED devices with glass/ITO/HATCN/TAPC/mCP/blue light-emitting material:DPEPO/TPBi/LiF/Al were prepared.The driving voltage of the device is 4.3V,4.3V and 3.9V,respectively,and the maximum brightness can reach 1668 cd·m^-2,936 cd·m^-22 and 3850 cd·m^-2respectively,and all of them emit dark blue light.After testing,the corresponding devices of 24PQ-PPC has a maximum external quantum efficiency of 2.64%.In addition,the dark blue light emitted by 4PQ-PPC devices has high purity and is close to the standard blue light level.Although the external quantum efficiency of the device is not high,its CIE deviation is very small under different voltages,showing excellent color stability.