【摘要】 制备了结构为ITO/MoO3(40nm)/NPB(40nm)/TCTA(10nm)/CBP:Ir(ppy)2acac(14%)(30nm)/BCP(10nm)/Alq3(30nm)/LiF(1nm)/Al(100nm)的绿色磷光有机电致发光器件(OLED),通过测量不同电压下器件的亮度、温度、电流和效率等参数,利用瓦格纳热击穿理论和空间电荷限制电流模型等理论对器件的热电击穿特性进行了分析和实验研究,进而找到提高OLED寿命的方法。结果表明,在电压较小时,随着时间的增加,器件的温度基本稳定在20℃,器件的亮度基本稳定在80~400cd/m2,器件的电流效率基本稳定在40~60cd/A。在电压较高时,随着时间的增加,器件的温度在114s内由22.16℃上升到35.91℃,器件的亮度在193s内由17 380cd/m2降低到7 585cd/m2,器件的电流效率在106s内由0.122 208cd/A降低到0.054 515 2cd/A。原因为,电压较小时,载流子获得能量较少,迁移速度较为缓慢,使得器件电流较小,产热少,热量能够及时散发出去;而当电压较高时,获得足够能量的电子和空穴运动加剧,器件内部的电流也急剧增大,产热大于散热,温度升高较快,器件最终出现了热电击穿,使其性能出现衰减。这表明,OLED的散热对其击穿有着非常重要的影响,良好的散热条件能够降低器件热电击穿现象发生的概率,进而提高OLED的寿命。更多还原

【Abstract】 The green phosphorescent organic light emitting diode(OLED)device with the structure of ITO/MoO3(40 nm)/NPB(40 nm)/TCTA(10 nm)/CBP:Ir(ppy)2 acac(14%)(30 nm)/BCP(10 nm)/Alq3(30 nm)/LiF(1 nm)/Al(100 nm)were prepared.By measuring the luminance,temperature,current and efficiency and other parameters under different voltages,the thermoelectric breakdown characteristics of the device are analyzed and studied by Wagner thermal breakdown theory and space-charge limiting current model.So that we can find a way to improve the lifetime of OLED device.The results show that when the voltage is small,with the increase of time,the temperature of the device is basically stabilized at 20℃the luminance of the device is basically stabilized at 80-400 cd/m~2,and the current efficiency of the device is basically stabilized at 40-60 cd/A.When the voltage is high,with the increase of time,the temperature of the device rises from 22.16℃to 35.91 ℃in 114 s,the luminance of the device is reduced from 17 380 cd/m~2 to 7585 cd/m~2 in 193 s,and the current efficiency of the device is reduced from0.122 208 cd/A to 0.0545152 cd/A in 106 s.That is because when the voltage is small,the carrier has less energy,and the migration speed is slow,which makes the current of the device smaller and also makes less heat generation so the heat can be sent out in time.However,when the voltage is high,themovement of electrons and holes is intensified and the current inside the device also increases rapidly,the heat generation is greater than the heat dissipation so the temperature rises rapidly.The device finally appears the thermoelectric breakdown,so that the performance of the devices is reduced.It can be seen that the heat dissipation of OLED devices has a very important impact on the breakdown.A good heat dissipation condition can reduce the probability of thermoelectric breakdown of the device,and then extend the lifetime of OLED devices.更多还原