EffectofNaCldopedintoBphen详解.PDF

Chin. Phys. B Vol. 23, No. 8 (2014) 087811 Effect of NaCl doped into Bphen layer on the performance of tandem organic light-emitting diodes Xiao Zhi-Hui( 肖志慧)abc , Wu Xiao-Ming(吴晓明)abc† , Hua Yu-Lin(华玉林)abc‡ , Bi Wen-Tao(毕文涛)abc , Wang Li(王 丽)abc , Zhang Xin(张 欣)abc , Xin Li-Wen(辛利文)abc , and Yin Shou-Gen(印寿根)abc a) School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China b) Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin 300384, China c) Tianjin Key Laboratory of Photoelectric Materials and Devices, Tianjin 300384, China (Received 26 December 2013; revised manuscript received 13 February 2014; published online 10 June 2014) To improve the performance of tandem organic light-emitting diodes (OLEDs), we study the novel NaCl as n-type dopant in Bphen:NaCl layer. By analyzing their relevant energy levels and carrier transporting characteristics, we discuss the mechanisms of the effective charge generation layer (CGL) of Bphen:NaCl (6 wt%)/MoO3 . In addition, we use the Bphen:NaCl (20 wt%) layer as the electron injection layer (EIL) combining the CGL to further improve the performance of tandem device. For this tandem device, the maximal current efficiency of 9.32 cd/A and the maximal power efficiency of 1.93 lm/W are obtained, which are enhanced approximately by 2.1 and 1.1 times compared with those of the single- emissive-unit device respectively. We attribute this improvement to the increase of electron