Synthesis And Electroluminescent Device Research Of Blue Emitters Based On Anthracene Derivatives

Organic Light-Emitting Device(OLED)has become a new generation of display technology because of its high image quality,good contrast,fast response time,high resolution,thinness and other advantages.As one of the three primary color light,blue light materials play an important role in the development of OLED.However,for many years,the performance of blue OLED is still inferior to green and red OLED.Due to the inherent wide bandgap and quenching effect caused by aggregation of blue light materials,the development of blue light materials with high emissivity is still a major problem that researchers need to overcome.In order to solve this problem,this paper synthesizes a series of blue luminescent materials using anthracene as a bridge design.The main research contents are as follows:1.Three blue light materials,TPA-AN-p PY,TPA-AN-m Py and TPA-AN-Pm,were designed and synthesized,and their basic physical properties and electroluminescence properties were tested and characterized.The Highest Occupied Molecular Orbital(HOMO)and Lowest Unoccupied Molecular Orbital(LUMO)of these three molecules overlap and separate,indicating that there may be both LE and CT states within the molecule.In the solvent chromogenic effect experiment,these three molecules exhibited the LE state under low polarity conditions,the CT state under high polarity conditions,and the two coexisted under medium polarity conditions.Non-doped OLED devices were prepared based on TPA-AN-p PY,TPA-AN-m Py and TPA-AN-Pm,all of which realized blue light emission,and the TPA-AN-Pm-based devices had the best performance.Its turn-on voltage is 2.7 V,the emission wavelength is 480nm,and the maximum current efficiency(CE)and external quantum efficiency(EQE)are 9.64 cd/A and 4.41%,respectively.2.Three blue light materials,CZ-AN-Py CN,2CZ-AN-Py CN and 3CZ-AN-Py CN,were designed and synthesized,and their basic physical properties and electroluminescence properties were tested and characterized.The singlet state(S1)levels of CZ-AN-Py CN,2CZ-AN-Py CN and 3CZ-AN-Py CN are 2.93 e V,2.80 e V and2.84 e V,respectively,and the triple state(T1)energy levels are 1.73 e V,1.72 e V and1.73 e V,respectively.2E(T1)>E(S1),which supports the occurrence of intramolecular TTA processes.In the solvent chromogenic experiment,these three materials exhibited only a strong CT state.Non-doped OLED devices were prepared based on CZ-AN-Py CN,2CZ-AN-Py CN and 3CZ-AN-Py CN,all of which achieved blue light emission.Among them,the maximum EQE of devices based on CZ-AN-Py CN and 3CZ-AN-Py CN was5.07%and 6.43%,respectively,which broke through the limitation of 5%EQE of traditional fluorescent materials,which may be due to the effective occurrence of TTA process.The non-doped device with 3CZ-AN-Py CN as the light-emitting layer has also demonstrated its excellent performance in other aspects,with a maximum brightness of30600 cd/m~2,a maximum CE of 14.4 cd/A,and a narrow half-peak width.