| Organic light-emitting diodes（OLED）is shining in the field of flat plates and solid lighting.It has the advantages of full solid-state self-light,ultra-wide-angle display,high contrast,and ultra-thin quality,so it has been favored by industry insiders.Organic electronic transmission materials（ETM）,as an component of OLED devices,assist the electrons to inject the luminous layer from the cathode,and also avoid the luminous luminousness caused by the direct contact of the cathode and the luminous layer.stability.Although a considerable number of organic electronic transport materials have been reported,the market’s pursuit of more efficient and stable OLED devices also poses new challenges to organic electronic transport materials.Anthracene derivatives have the advantages of good film-forming and stability,certain carrier transport capacity,and strong chemical modification,so this paper systematically studies the development of excellent electron transport materials based on anthracene units.The main contents are as follows:Four anthracene-based organic electron transport materials ETM111,ETM119,ETM120and ETM139 were designed and synthesized by introducing pyrimidine and oxazole groups on the anthracene unit.The UV-Vis absorption spectrum,differential scanning calorimetric curve,thermogravimetric curve and energy level distribution were tested.The measurement and calculation results show that the band gap width of these compounds had a small difference,about 3.05 e V.The thermal decomposition temperature was above 370°C,and it has high thermal stability.There were lower LUMO（lowest unoccupied molecular orbitals）energy levels,both below-2.8 e V.Four compounds were doped with Liq（1:1 wt/wt）to prepare a single electronic device,and the J-V curve of the single electron device was measured,and then the zero-field electron mobility of ETM111,ETM119,ETM120 and ETM139 were calculated to be 9.94×10-8 cm2·V-1·s-1,8.32×10-9 cm2·V-1·s-1,1.03×10-6 cm2·V-1·s-1and 3.13×10-9 cm2·V-1·s-1.The electron mobility of these materials at an electric field strength of 5×105 V·cm-1 were1.2×10-4 cm2·V-1·s-1,1.07×10-5 cm2·V-1·s-1,1.21×10-3 cm2·V-1·s-1 and 4.07×10-6 cm2·V-1·s-1,respectively.Materials ETM111 and ETM120 containing pyrimidine groups showed higher electron mobility in 4 material tests.Then,pyrimidine groups were introduced on the anthracene unit,and three asymmetric anthracene-based organic electron transport materials ETM122,ETM131and ETM132 with similar structures were designed and synthesized.The UV-Vis absorption spectrum,differential scanning calorimetric curve,thermogravimetric curve and energy level distribution were tested.The measurement and calculation results show that the band gap width of these compounds also had a small difference,about 3.05 e V.There wae no obvious glass transition temperature,and the thermal decomposition temperature was above 400°C,which had high thermal stability;LUMO energy levels were all below-2.8 e V.The single-electron device was prepared by doping three compounds with Liq（1:1 wt/wt）,and the J-V curve of the single-electron device was measured,and then the zero-field electron mobility of ETM131,ETM132 and ETM122 were calculated to be 1.24×10-10 cm2·V-1·s-1,2.00×10-8 cm2·V-1·s-1 and6.14×10-9 cm2·V-1·s-1.The electron mobility of these materials at an electric field strength of5×105 V·cm-1 were 1.73×10-7 cm2·V-1·s-1,2.59×10-5 cm2·V-1·s-1 and 7.96×10-6 cm2·V-1·s-1,respectively.Based on the difference in electron mobility between ETM131 and ETM132,the interaction between pyrimidine-containing materials and cathodes was proved by simple work function test experiments,and the calculation results of the electrostatic potential on the molecular surface show that materials with low molecular surface electrostatic potential were more likely to obtain high electron mobility.Four organic electron transport materials ETM111,ETM122,ETM131 and ETM132containing pyrimidine groups were doped with Liq（1:1 wt/wt）as electron transport layers,and used to prepare blue OLED devices,and contrast devices were prepared based on commercially available electron transport materials under the same conditions.The device performance test results show that the device using ETM111 shows similar performance to the device using commercial materials,its blue light efficiency could reach 98%of that of commercially available material devices,the voltage at a current density of 10 m A/cm2 is only 113%of that of commercially available material devices,the brightness reaches 800 cd/m2,and the external quantum efficiency was 16.83%,and the comprehensive performance was close to that of commercially available materials,which had certain application potential. |
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