Study On High Performance Of White Organic Light Emitting Device

White organic light emitting device(WOLED) has achieved some progress in the luminous efficiency, brightness and lifetime, but there are still many problems to be solved, such as the complex structure, the poor stability, and the serious efficiency roll-off of the device. This article does in-depth research on the control of carrier composite, improvement in the efficiency and the stability of the device, and simplifying device structure. The specific research includes the following contents:(1) In the double-layer complementary color light emitting layer in the device, we firstly achieved the ladder shape hole transport layer by fixing the position between the organic evaporation source and the substrate. The hole transport layer material TAPC in the whole luminous point increases from 10 nm to 30 nm in thickness, which changes the carrier recombination position and shape. Because the hole transport ability progressively changes. The carrier composite shape can improve the efficiency and the spectral stability of the device by reducing the energy transfer between the blue layer and yellow layer. The current efficiency of this device is 31.4 cd/A.(2) Fabricating and optimizing a blue phosphorescent OLED by doping Firpic materials as emitter into a new type of main material named DNCz PS, we systematically study the effects of host guest doped ratio in the emitting light layer, thickness of hole transport layer and thickness of electron transport layer on the device performance. The current efficiency of the optimized device can reach 39.7 cd/A. Therefore, white organic light emitting device(WOLED) is respected because of highly efficiency of the blue OLED. And systematically study the effect of layer thickness and location of the yellow light emitting layer on the performance of the white organic light emitting device. When the thickness of the yellow emitting layer is 0.25 nm, and the distance between the blue light-emitting layer and the yellow emitting layer is 3 nm, the device achieves the best performance. The current efficiency, power efficiency and external quantum efficiency were 40.6 cd/A, 32.3 lm/W and 16.4%. Finally, we also try to fabricate a green TADF device by doping the delayed fluorescence materials named 4Cz IPN into the DNCzPS as main material, obtaining an outstanding device. The current efficiency, power efficiency and the external quantum efficiency were 38.5 cd/A, 27.3 lm/W and 15.2%.(3) Single molecular white organic light emitting device is fabricated by using the small molecule, such as F, FF and the polymer, such as PF based on N,N-difluorenevinylaniline. The current efficiency, power efficiency, external quantum efficiency and the CIE coordinates of single molecular devices based on F are 0.79 cd/A, 0.73 lm/W and 0.6%,(0.32; 0.33); The current efficiency, power efficiency, external quantum efficiency and the CIE coordinates of single molecular devices based on FF are 1.75 cd/A, 1.61 lm/W and 1.3%,(0.26; 0.30); The current efficiency, power efficiency, external quantum efficiency and the CIE coordinates of single molecular devices based on PF are 4.5 cd/A, 4.2 lm/W and 2.6%,(0.32; 0.30).