Design,synthesis And Properties Of D-a Bipolar Small Molecular Photoelectric Materials

With the development of the world economy,OLED technology is also developing.Currently,OLED technology has a very broad development prospect in the field of lighting,so high-performance devices are the key to the industrialization of OLED.Optimizing the performance of materials in the luminescent layer(EML)is of great significance to the development of efficient OLED.At present,the luminescent layer is mainly host-guest doped structure,among which D-A type host material is the focus of this thesis.A series of D-A type small molecule host materials are obtained through design and synthesis,and their photoelectric properties and device performance are tested.The following is a brief introduction to the main content of each chapter:(1)In the first chapter,this thesis introduces the development of organic luminescent materials,status quo and related principles of organic light-emitting devices.And the research progress of small molecule phosphorescent main materials is reviewed,mainly from the different chemical structure of the main material,classification of all kinds of main materials are summarized.(2)In Chapter 2,A series of D-A main materials TPATRZ,Cz TRZ and POXTRZ are designed and synthesized according to ortho connection strategy,and their related properties are tested.The conformation of the molecule is highly distorted by ortho-linking,which reduces the conjugation degree and keeps the high triplet energy.When the receptor unit is the same,different donor unit has a certain effect on the basic properties of the three materials.The red phosphorescent devices using the above three molecules as main materials have high external quantum efficiency(>20%),and the devices using POXTRZ as main material achieve the highest external quantum efficiency of 24.0%and the minimum efficiency roll down of 6.3%at 1000 cd/m~2.These results further expand the possibility of D-A type host materials in ortho connection mode,which has A broad application prospect in OLED.(3)In Chapter 3,In order to further improve the electronic transmission performance of molecular TPATRZ,a series of principal materials such as 3FTPATRZ,4FTPATRZ,5FTPATRZ and 6FTPATRZ were synthesized by introducing fluorine atoms at different positions on the parent benzene ring,and their properties were tested.Compared with the parent molecule TPATRZ,the HOMO and LUMO energy levels of these molecules have decreased,which promotes electron injection.TheΔHOMO-LUMO gap of 3FTPATRZ(+0.06 e V)and 6FTPATRZ(+0.04 e V)increases,which improves the electroluminescence efficiency of the device.Devices based on3FTPATRZ and 6FTPATRZ will also achieve good results.It also shows that the D-A main material obtained by introducing fluorine atoms at different positions has A certain application prospect in OLED applications.This thesis contains 63 graphs,9 tables and 123 references.