Effect of different spacers for performance enhancement on white organic light-emitting devices based on double emissive layers with homogeneous p-/n-type host
- 作者：Junsheng Yu ; jsyu@uestc.edu.cn ; Juan Zhao ; Lei Zhang ; Jian Zhong
- 关键词：White organic light-emitting device ; Double emissive layers ; p-/n-type host ; Spacer
- 刊名：Current Applied Physics
- 出版年：2012
- 期刊代码：15_15671739
- 类别：ph
- 出版时间：July, 2012
- 卷：12
- 期：4
- 页码：1212-1216
- 文件大小：742 K
摘要
White organic light-emitting devices (WOLEDs) based on phosphorescent blue and yellow emitters were fabricated, while p-type di-(4-(N,N-ditolyl-amino)-phenyl)cyclohexane (TAPC) and n-type 2,2鈥?2鈥?(1,3,5-benzenetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) were separately utilized as a homogeneous host for both blue and yellow emissive layers (EMLs). Then, various spacers were inserted between the two EMLs for performance characterization. The results showed that for the TAPC-host devices, a device using 4,7-diphenyl-1,10-phenanthroline (Bphen) as the spacer had a maximum current efficiency (CE) of 11.3聽cd/A, while stable white light emission with Commission Internationale del鈥橢clairage (CIE) coordinates of (0.394, 0.435) at a bias of 5聽V was observed. Similarly, among the TPBi-host devices, a device using 4,4鈥?bis(carbazol-9-yl)biphenyl (CBP) as the spacer exhibited a maximum CE of 18.1聽cd/A, accompanied by negligible color variation with the CIE coordinates of (0.284,0.333) at 5聽V. For the double-EML devices, the improved device efficiency and color stability by introducing proper spacer was attributed to broadened recombination region and efficient energy transfer between the EMLs.