新型双极性TPABMI的高效率非掺杂蓝色OLED

High efficiency nondoped blue OLEDs based on novel ambipolar blue emitting material TPABMI

通过研究双极性蓝色荧光染料对(4-三苯胺)-联二苯基-(2-苯基)苯并咪唑(TPABMI)的电致发光(EL)特性,发现TPABMI不仅具有较强的发光特性,同时还具有较强的空穴/电子传输特性。利用此特性,制备了蓝光器件ITO/NPBX(40nm)/TPABMI(20nm)/TPBi(20nm)/LiF(0.5nm)/Al(93nm);进而在空穴传输层NPB和发光层TPABMI之间插入TCTA薄层,并对ITO表面用MoO3进行修饰,制备了结构为ITO/MoO3(10nm)/NPB(80nm)/TCTA(5nm)/TPABMI(20nm)/TPBi(40nm)/LiF(1nm)/Al(100nm)的蓝色OLED。实验结果表明,器件在16V电压下实现了蓝光发射,发光波长为464nm,色坐标为(0.150 9,0.143 8),最大发光亮度为18 970cd·m-2,获得最大发光效率为5.48cd·A-1;器件效率由启亮后6V时的3.53cd·A-1到14V时的3.66cd·A-1比较稳定,从15V时的3.89cd·A-1到16V时的5.48cd·A-1有一个很大的提升;器件的色度从启亮到获得最大亮度的过程中比较稳定。

We investigate the electroluminescence （EL） characteristics of a novel blue emitting material TPABMI. The results demonstrate the TPABMI with strong blue emitting and hole-electron transpor- ting ability. Based on the performance,an un-doping blue organic light-emitting device （OLED） was fab- ricated. The blue device structure is as follows：ITO/NPBX（40 nm）/TPABMI（20 nm）/TPBi（20 nm）/ LiF（0.5 nm）/Al（93 nm）. A series of blue devices were fabricated by inserting TCTA thin layer be- tween the hole-hole transport layer NPB and emitting layer TPABMI,and inserting ITO buffer layer of MolDs. It has the configuration of ITO/MoO3 （10 nm）/NPB（80 nm）/TCTA （5 nrn）/TPABMI（20 nm）/ TPBi（40 nm）/LiF（1 nm）/Al（100 nm）. Blue OLEDs were obtained with the maximum emission wave- length at about 464 nm and the Commission International de L Eclairage coordinates of （ 0. 150 9, 0. 143 8） ,the maximum luminance is 18970 cd m-2 and the maximum luminous efficiency of 5.48 cd A-1 at an applied voltage of 16 V. The efficiency slightly varies from 6 V （3. 53 cd A-1 ） to 14 V （3.66 cd A 1 ） ; The CIE coordinates slightly vary from （0. 158,0. 1469） to （0. 150 9,0. 143 8） when the voltage shifts from 6 V （6 cd m-2） to 16 V （18970 cd m-2）.