| Organic light-emitting diodes(OLEDs)are competitive candidates for the next generation flat-panel displays and solid state lighting sources.In the full-color display,red,green and blue as the three primary colors are particularly important.In recent years,there are many reports related red and green OLEDs materials.But the research progress for blue light materials is very slow because of its large energy gap.Thus,how to obtain an excellent blue light material and to build a blue light emitting OLEDs has become a very hot research topic.The development process of devices is from simple single-layer devices gradually to multilayer devices,and from doped devices gradually to non-doped devices.Meanwhile,the development of emitter layer material is also gradually from one function to multifunctions with light-emitting group,electron transport and hole-injection group.Due to their important commercial values,it is urgent to design and prepare the blue organic electroluminescent materials and devices with excellent photoelectric properties.The aim of this thesis is to obtain blue light emitting conjugated organic molecules and corresponding devices.We designed and synthesized two types(small molecule and polymer)blue organic electroluminescent materials.Their photophysical properties,electrical properties,thermal stabilities and device performances were studied.This thesis mainly includes the following four aspects:The first chapter:A brief overview of the recent development progress and design ideas of organic light-emitting diodes.At the same time,the main topic of paper is also proposed.The second chapter:Two small molecule blue emission compounds were synthesized,in which pyrene ring as the main emission group connected with a hole-transporting group(carbazole ring)and an electron injection group(oxadiazole),respectively.The photophysical properties of the two compounds show the emission peaks are at 430-440 nm,which is matched with typical blue light emitting regions.The two compounds have high thermal stabilities and high luminous efficiencies.The results of electrochemical experiments are well anastomotic with theoretical calculations.The CIE of the materials are(0.17,0.11)and(0.16,0.15),respectively.The performances of the devices based on the two compounds as emitters indicate that both of them meet the technical parameters of the electroluminescent materials.Owing to their different electronic distributions,the compound with pyrene and carbazole units(BCP)processes more excellent optoelectronic properties.The third chapter:Four new?-conjugated polymers with 8-methoxyquinoline and aromatic derivatives were designed and synthesized.In this chapter,we studied the optical and electrical properties of polymer PCQH,in which 8-methoxyquinoline acts as electron transport and light emission group,carbazole is hole-transport group.Polymer PCQH has a high thermal stability(decomposition temperature is 295?and glass transition temperature is 250?).The emission peak of PCQH is around 440 nm and the fluorescence quantum yield is 81%in CH3C1.The studies with electron donor and electron acceptor indiacte that the polymer has excellent electron transport properties.The results of electrochemical experiments are also well matched theoretical calculations.Preliminary results reveal that the polymer has potential to be a blue electroluminescent material.The further work is to fabricate electroluminescent device by using the polymer PCQH as an emitter.The fourth chapter:Summary and outlook. |
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