Synthesis And Properties Of Triarylborane-pyrrolo[3,2-b]pyrrole Compound With AIE Properties

OLED has attractive features such as beauty,thinness,flexibility,low power consumption and high contrast.It is considered to be the next-generation new display flat panel technology and is now widely used in the display screens of smart phones and televisions.As the light-emitting layer of the core of the OLED,the small organic compound has the advantages of easy structure modification,easy synthesis and easy purification.However,most of them have the problem of aggregation-induced quenching?ACQ?in the solid state.On the contrary,the luminous efficiency of aggregation-induced emission?AIE?materials in the aggregated state is higher,and the emergence of AIE breaks through the plight of OLED development.Pyrrolo[3,2-b]pyrrole and its derivatives are a new kind of organic light-emitting materials.Its structure is composed of two pyrrole rings,which have large planar rigid conjugated structure.What's more,there are 10 ? electrons separated from each other,which makes it have strong electron-donating ability.Thus,it is an important unit for the synthesis of various small molecules and polymers.In triarylborane,the boron atom has an empty p-orbital,and it has a strong electron-deficient property when it is connected to an aromatic compound.Therefore,triarylborane is often used as a strong electron acceptor.Based on this,the compound DMBPDPP containing pyrrolo[3,2-b]pyrrole-triarylborane was designed and synthesized,and the structure of the compound was systematically characterized.The thermal stability,photophysics and electrochemical properties of the compound were also studied.What's more,the characteristics of doped and non-doped OLEDs manufactured using the compound as a light emitting layer are also studied in detail.The main contents are as follows:?1?The development and mechanism of OLED,the AIE phenomenon and current progress,pyrrolo[3,2-b]pyrrole compounds and triarylborane compounds are introduced.?2?A new material DMBPDPP with aggregation-induced emission properties was designed and synthesized by combining triarylborane units with pyrrole[3,2-b]pyrrole skeleton,and the structure of the compound was characterized.The thermal stability,photophysical properties,electrochemical properties and AIE properties of DMBPDPP were studied.The results show that the Td of DMBPDPP is 347?,which indicates that it has good thermal stability.The HOMO / LUMO orbital electron cloud arrangement and energy level were calculated through DFT.The results show that DMBPDPP has a distorted conformation,which can reduce the ?-? interaction and produce AIE characteristics.The AIE characteristics of DMBPDPP were confirmed by spectroscopic studies of THF-H2 O solvents in different proportions.The cyclic voltammetry method was used to test the electrochemical performance.The results showed that the electrochemical performance was stable,and the HOMO / LUMO energy level was further verified experimentally.?3?Non-doped and doped OLEDs was constructed with DMBPDPP as the light-emitting layer,and its electroluminescence properties were systematically tested.The results show that the compound is a good green light material.The maximum current efficiency of the non-doped device A based on DMBPDPP is 5.90 cd A^-1,the turn-on voltage is 3.3 V,the maximum brightness is 4158 cd m-2,the maximum external quantum efficiency is 0.61%.The turn-on voltage of the 3% doped device B is 3.3V,the maximum current efficiency is 7.90 cd A^-1,the maximum brightness is 13340 cd m-2,the maximum external quantum efficiency is0.79%,and the maximum power efficiency of 7.52 lm W^-1.The turn-on voltage of the 5% doped device C is 3.0 V,the maximum power efficiency of 8.40 lm W^-1,the maximum brightness is 13500 cd m-2,the maximum current efficiency is 8.6 cd A^-1,and the maximum externalquantum efficiency is 0.77%.The maximum current efficiency of the 8%doped device D is 8.9 cd A^-1,turn-on voltage of is 3.0 V,the maximum current efficiencyis 8.9 cd A^-1,the maximum brightness is 13400 cd m-2,the maximum power efficiency of 9.01 lm W^-1,and the maximum external quantum efficiency is 0.87%.