空穴传输层NPB中掺杂Alq3制备高性能的蓝光器件

Using doped Alq3 in NPB Hole Transmistion Layers to Produce High Performance Bule Organic Lighe Emitting Devices

研究了在空穴传输层NPB中掺杂Alq3制备高性能的蓝光有机电致发光器件(OLED)。采用传统的材料和结构,在空穴传输层NPB中掺杂Alq3,在掺杂浓度为3%时,OLED的色坐标为(0.17,0.19)、亮度为10 770 cd/m2(在13 V时)和最大效率为4.1 cd/A。在同等条件下,Alq3掺杂降低了开启电压,在7 V时亮度达到了118.8 cd/m2。研究分析表明,OLED性能的提高是由于NPB的HOMO能级比Alq3的HOMO能级高,掺杂剂Alq3对空穴有散射作用,阻挡了部分空穴的传输,降低了空穴的迁移率;而Alq3又是很好的电子传输材料,Alq3掺杂提高了空穴和电子在发光层中的注入平衡,有利于激子的形成,从而提高了器件的性能。

We have designed a high performance bule emission device by using the do ped Alq3 in hole transmission layers of NPB. According to traditional material and structure,we have designed the new structure of the device reasonably and increased the efficiency of blue light emission effectively and conveniently. The commission international CIE coordination of the devices is very stable at （0.17,0.19）. The maximum electroluminescence efficiency is 4.1 cd/A at 11 V. The maximum brightness is 10 770 cd/m^2 at 13 V. Under equal conditions,the turn-on voltage also has reduced,the device luminance is 118.8 cd/m^2 at 7 V.The reason of these improvements is as follows：the HOMO level of the NPB is higher than that of the Alq3 at 0.3 eV,and the Alq3 molecule has scattering function to the hole, it has stopped the transmission of some holes,and reduced the mobility of hole; moreover Alq3 is a good material of electron and transmission, this adulterate can improve transfused balance of hole and electronic in the luminous layer,and it is beneficial to the formation of exciton,so it can enhance the capability of the device.