Study On The Effect Of New Electrodes On The Performance Of OLED Devices

OLED is a new generation of display technology,which has the advantages of electroluminescence,wide viewing angle,high contrast,fast response,low power consumption and wide temperature range.Moreover,it can realize flexible display.Electrode is an important factor affecting the performance of OLED devices,in order to improve the performance of OLED devices,the following work has been done in this thesis:(1)Based on green light OLED device ITO/HAT-CN/TAPC/CBP:Ir(ppy)3/TmPyPB/Liq/Al,this thesis studies the effect of anode ITO/Ag/ITO on device performance by replacing ITO.Studies have shown that replacing ITO with ITO/Ag/ITO has excellent photoelectric properties except that the starting voltage is slightly higher.ITO/Ag/ITO composite electrode can effectively reduce the energy level barrier of OLED device interface,making it easier for internal carriers to reach the cavity transport layer.When the magnetron sputtering thickness of ITO/Ag/ITO composite electrode is 80 nm,7 nm and 52 nm respectively,the device performance is the best.At the condition of 0.25 mA/cm2,the illumination voltage is 3.35 V,the maximum brightness is 31340 cd/m2,the maximum power efficiency is 90.58 1m/W,the maximum current efficiency is 96.68 cd/A,and the maximum external quantum efficiency is 25.22%.Compared with ITO devices,the maximum brightness of ITO/Ag/ITO devices increased by 6713 cd/m2,the highest current efficiency increased by 28.03 cd/A,the highest power efficiency increased by 26.29 1m/W,and the highest external quantum efficiency increased by 34.15%.(2)Based on green light OLED device ITO/Ag/ITO/HAT-CN/TAPC/CBP:Ir(ppy)3/Tm PyPB/Liq/Yb/Al,this thesis studies the influence of doping ratio of different Yb concentrations on device performance by doping Yb of different concentrations in Liq as an electron injection layer modified electrode.The research shows that doping with trace Yb in Liq can effectively improve the luminous efficiency of the device.When the doping ratio is 1.85%,the device performance is the best.Under the condition of 0.25 mA/cm2,the starting voltage is 3.65 V,the maximum brightness is 26720 cd/m2,the maximum power efficiency is 74.89 1m/W,the maximum current efficiency is 87.07 cd/A,and the maximum external quantum efficiency is 24.07%.Compared with the device with undoped and pure Al,the maximum brightness increased by 2181 cd/m2,the maximum power efficiency increased by 10.6 1m/W,the maximum current efficiency increased by 18.42 cd/A,and the maximum external quantum efficiency increased by 28.03%.(3)Composite new anode,modified electrode and cathode on a green light device,and the device is compared with other device which changes anode and cathode separately.It is found that ITO/Ag/ITO/HAT-CN/TAPC/CBP:Ir(ppy)3/TmPyPB/Liq/Yb/Al has the best performance.The starting voltage is 3.37V,the maximum brightness is 30011 cd/m2,the highest current efficiency is 97.35 cd/A,the highest power efficiency is 90.86 1m/W,and the highest external quantum efficiency is 25.38%.It shows that the combination of new anode and new cathode can effectively improve the photoelectric characteristics of the device.It is found that the highest current efficiency,the highest power efficiency and the highest external quantum efficiency of the comprehensive device are better than those of the anode device.The maximum current efficiency increased by 0.67 cd/A,the maximum power efficiency increased by 0.28 1m/W,and the maximum external quantum efficiency increased by 2.5%.