Study On The Factors Influencing The Life Of OLED

Since the organic electroluminescent device?OLED?was invented,its performance has been greatly improved.Although OLEDs have achieved primary industrialization at present,there are still some problems to be solved,such as the stability and life of the device still can't meet the requirements of the people.This article aims at the life of the device by measuring the temperature,luminance,current,and efficiency of the device under different driving voltages over time,using different functional layer thickness and doping to change the performance of the device,the breakdown characteristics and life of the device were investigated.The main contents of this paper are summarized as follows:?1?Breakdown characteristics of OLED devices.Respectively different driving voltage applied to the green fluorescence and phosphorescence of OLED devices,by measuring the variation of the luminance,temperature,current,and efficiency of the devices over time,the green fluorescent and phosphorescent OLED devices were studied in normal operation,thermoelectric breakdown and electrical breakdown occurred.?2?The effect of electron transport layer material on the thermoelectric breakdown characteristics and life of OLED devices.The thickness of the Alq₃electron transport layer of the green fluorescent OLED devices and the doping concentration of the Bphen electron transport layer of the green phosphorescent OLED devices were changed respectively.By measuring the variation of temperature,current and luminance of the device under different voltages with time,the effects of Alq₃ thickness and Bphen doping concentration on the breakdown characteristics of green fluorescent and phosphorescent OLED devices were studied,respectively.The results show that with the increase of electron transport layer Alq₃ thickness of the green fluorescent OLED devices,the thermoelectric breakdown voltage value of the device increases first and then decreases;With the increase of the doping concentration of Cs₂CO₃ in the Bphen electron transport layer of the green phosphorescent OLED devices,the thermoelectric breakdown voltage value of the device increases first and then decreases.Therefore,selecting an appropriate thickness of the electron transport layer and proper doping of the electron transport layer can respectively reduce the probability of occurrence of thermoelectric breakdown of the green fluorescent and phosphorescent OLED devices,thereby increasing the life of the device.?3?The effect of the material thickness of the hole transport layer on the thermoelectric breakdown characteristics and life of the OLED devices.The thickness of the NPB in the green fluorescent and phosphorescent OLED devices were changed respectively.By measuring the variation of temperature,current and luminance of the device under different voltages with time,the effect of NPB thickness on the breakdown characteristics of green fluorescent OLED devices and green phosphorescent OLED devices was studied.The results show that the value of the thermoelectric breakdown voltage of the device increases with the increase of the thickness of the device NPB.Therefore,increasing the thickness of the hole transport layer of the green fluorescent and phosphorescent OLED device can reduce the probability of thermoelectric breakdown of the device,thereby increasing the life of the device.