The Study On New White Phosphorescent Organic Light-emitting Device

Organiclight-emittingdevices(OLEDs),withthecharacteristicsofself luminescence,fast response,high efficiency,wide viewing angle and flexibility,are regarded as the next generation of display and solid-state light source.the white OLED devices in the flat panel display,solid-state lighting and liquid crystal display backlight source has shown great potential for applications,has been widely concerned and become one of the global research hotspot.After more than 20 years of in-depth study,both the structure,materials and preparation process,white OLED devices have made considerable progress.However,at present,there are many shortcomings in the white OLED devices,such as lack of luminous efficiency and light-emitting color easy to drift.In this thesis,white OLED as the research object,and the influence factors of the efficiency and color stability have been studied.besides,through different ways to improve the white OLED performance,so as to achieve high efficiency,high color stability of white emission.This thesis includes three parts:1.First of all,the study of multi-emitting layer white OLED.The FIrpic is doped into TCTA and TmPyPB to form double blue-emitting layers(D-BEML),(MDQ)2(acac):TmPyPB is inserted into the D-BEML,Combining TCTA and TmPyPB which have effective blocking effect on the carriers and excitons,and thus mixed to achieve white light.The influence of the red emitting layer on the luminescent properties of the device is studied under different thickness and doping concentration.The results shows that the optimum performance of OLED is achieved when the thickness of Ir(MDQ)2(acac):Tm PyPB red emitting layer is 2 nm,and the doping concentration is 5 wt%,WOLEDs with peak efficiencies of 11.50 cd/A and CIE coordinates of(0.339,0.337)are achieved.2.The effect on the performance of blue light-emitting OLED devices when FIrpic doping in different host materials is studied,When the host material is TCTA,the device exhibits better carrier balance characteristics.On this basis,the performance of the devices are improved by optimizing the doping concentration and the thickness of the light-emitting layer,When the concentration of FIrpic is 8%and the thickness of the luminescent layer is 25 nm,the luminous performance of blue OLED is the best.maximum current efficiency reached 9.34 cd/A,the brightness of 16V reached 1230cd/m~2.3.Different concentrations of DCJTB color conversion film is prepared by spin coating method,and combing with the optimized highly efficient blue OLED devices devices,White light emission was achieved.When the concentration of DCJTB is 1%,the white light device with perfect photoelectric performance is obtained.The maximum current efficiency of the device is 5.66 cd/A.When the voltage is 11 V,the color coordinates of the device is(0.330,0.339),very close to the pure white light(0.333,0.333).When the driving voltage increases from 11 V to 17V,the range of color coordinates is(±0.007,±0.026),which shows excellent color stability.