1. Institute of Optoelectronics Technology, Beijing Jiaotong University, and Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing 100044，China 2. BOE Technology Group Co., Ltd, Beijing 100016, China
Abstract：The changes of exciton generation region are influenced by varying electric field, which affect the color and efficiency performance of devices. Firstly, The authors fabricated two types of phosphorescent light emitting devices, device 1：ITO/PEDOT∶PSS/PVK∶Ir(ppy)3∶DCJTB (100∶2∶1 wt)/ BCP(10 nm)/Alq3(15 nm)/Al, and device 2：ITO/PEDOT∶PSS/PVK∶Ir(ppy)3 (100∶2 wt)/BCP (10 nm)/Alq3 (15 nm)/Al. The authors investigated the influences of electric field on exciton generation region in single-layer and multi-doped structure devices. Analysis of the electroluminescence spectrum under different voltages indicates that the emitting of Ir(ppy)3, PVK and DCJTB was enhanced with the increase in applied voltages. Compared to Ir(ppy)3, the emitting of PVK and DCJTB was prominently enhanced. This is because under high electric field it is easier for high energy carrier to generate high energy exciton, and the emitting of wide-band-gap material PVK is stronger; on the other hand, the authors investigated the results from the aspect of energy band gap. DCJTB is narrow-band-gap material, which can capture carrier comparatively easily and emit stronger light. At the same time, we obtained a new emission peak located at 460 nm, which becomes comparatively weak with increasing voltage. In order to explore the reason, we fabricated the device: ITO/PEDOT∶PSS/PVK∶BCP∶Ir(ppy)3 (x∶y∶2 wt)/Alq3 (15 nm)/Al. The 460 nm emission peak doesn’t disappear by changing the mass ratio of x and y. The authors speculate that the emission peak relates to PVK and BCP.
Key words：Phosphorescence;Electric field;Exciton;Generation region
刘旭东1,赵谡玲1,宋丹丹1,占红明1, 2, 袁广才1, 2,徐 征1* . 电场变化对有机磷光器件中激子形成影响的研究[J]. 光谱学与光谱分析, 2009, 29(09): 2321-2324.
LIU Xu-dong1,ZHAO Su-ling1,SONG Dan-dan1, ZHAN Hong-ming1, 2 , YUAN Guang-cai1, 2, XU Zheng1* . Study of Exciton Generation Region of Phosphorescent Light Emitting Devices Based on the Changing Electric Field. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2009, 29(09): 2321-2324.
[1] ZHANG Yan-fei, XU Zheng, ZHANG Fu-jun, et al(张妍斐，徐 征，张福俊，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2008, 28(4): 760. [2] Lee Jiun-Haw, Huang Chih-Lun, Hsiao Chih-Hung, et al. Appl. Phys. Lett., 2009, 94: 223301. [3] Tsuzukia Toshimitsu, Tokito Shizuo. Appl. Phys. Lett., 2009, 94: 033302. [4] Fukagawa H, Watanabe K, Tsuzuki T, et al. Appl. Phys. Lett., 2008, 93: 133312. [5] Lee Hyunbok, Cho Sang Wan, Han Kyul, et al. Appl. Phys. Lett., 2008, 93: 043308. [6] Liaoa L S, Klubek K P. Appl. Phys. Lett., 2008, 92: 223311. [7] Dinh Nguyen Nang, Chi Le Ha, Thuy Tran Thi Chung, et al. Journal of Applied Physics, 2009, 105: 093518. [8] Yang Suhua, Hong Bocheng, Huang Shihfong. Journal of Applied Physics, 2009, 105: 113105. [9] Simon J Martin, Geraldine L B. Verschoor Matthew A, et al. Organic Electronics, 2002, 3: 129. [10] Meerheim R, Scholz S, Olthof S, et al. J. Appl. Phys., 2008, 104: 014510. [11] Kang Jae-Wook, Lee Se-Hyung, Park Hyung-Dol, et al. Appl. Phys. Lett., 2007, 90: 223508. [12] Kim Young Min, Park Young Wook, Choi Jin Hwan, et al. Appl. Phys. Lett., 2007, 90: 033506. [13] Yang Shengyi, Liu De’ang, Jiang Yan, et al. Journal of Luminescence, 2007, 122-123: 614. [14] Cheng Gang, Zhang Yingfang, Zhao Yi, et al. Appl. Phys. Lett., 2005, 87: 013506. [15] Itano K, Ogawa H, Shirota Y. Appl. Phys. Lett., 1998, 72: 636. [16] Lee D U, Yoon Y B, Baek S H, et al. Thin Solid Films, 2008, 516: 3627. [17] Zhang Guang, Li Wenlian, Chu Bei, et al. Organic Electronics，2009, 10: 352.
