插入电荷控制层对蓝色OLED发光性能的提高

Improvement of Performance of A Blue Organic Light-emitting Diode by Inserting Charge Control Layers

用蓝色有机荧光材料N6,N6,N12,N12-tetrap-tolylchrysene-6,12-diamine(DNCA)作为发光层,在发光层中间以及发光层与电子传输层之间插入2-methyl-9,10-di(2-napthyl)anthracene(MADN)和9,10-di(2-naphthyl)anthracene(ADN)作为电荷控制层,制备了结构为ITO/NPB(40 nm)/DNCA(15 nm)/MADN(3nm)/DNCA(15 nm)/ADN(3 nm)/Bphen(30 nm)/LiF(0.8 nm)/Al(120 nm)的蓝色有机电致发光器件(OLED)。该器件的最大电流效率和最大亮度分别为5.6 cd/A和23 310 cd/m2。与传统的单发光层器件相比,最大电流效率和最大亮度分别提高了70%和87%。器件发光性能的提高可归结于两个电荷控制层在整个器件中的协同作用。第一电荷控制层MADN的作用主要是将发光层区域分成两个部分,从而扩大了激子在发光层中的复合区域;第二电荷控制层ADN可以有效地将空穴限制在发光层中,避免了激子在电子传输层中形成的无辐射跃迁从而提高了器件的发光性能。

The performance of blue fluorescent organic light-emitting device (OLED) with N6, N6, N12, N12-tetrap-tolylchrysene-6, 12-diamine (DNCA) as emitting layer (EML) was improved by inserting 2-methyl-9, 10-di(2-napthyl)anthracene (MADN) 9, 10-di(2-naphthyl)anthracene (ADN) as charge control layers (CCLs) into the device. For the optimum device with CCL structure of ITO/NPB (40 nm)/DNCA(15 nm) /MADN(3 nm) /DNCA(15 nm)/ADN(3 nm)/Bphen(30 nm)/LiF(0.8 nm)/Al(120 nm), the maximal current efficiency of 5.6 cd/A and the maximal luminance of 23 310 cd/m2 were achieved, which were enhanced by 70% and 87% comparing with the control device (CD) without CCLs, respectively. The performance improvement of the device can be attributed to the synergistic action (function) of the two CCLs. By utilizing the CCL structure, the original emitting zone can be separated into two parts by inserting MADN in the first EML, and the exciton formation region can also be broadened accordingly. Therefore, the exciton's radiative process can be utilized to a great extent. Meanwhile, the holes can be effectively confined in the second EML by inserting ADN between the EML and ETL, which can prevent the exciton's non-radiative process in the ETL so as to improve the device performance.