Journal of Luminescence 122–123 (2007) 678–682 Efficient organic electroluminescent devices based on an organosamarium complex Jiangbo Yu a , Hongjie Zhang a,Ã , Liang Zhou a , Ruiping Deng a,b , Zeping Peng a,b , Zhefeng Li a,b , Lianshe Fu a , Zhiyong Guo a,b a Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. 5625 Renmin Street, Changchun (130022), PR China b School of Chinese Academy of Sciences, China Available online 23 March 2006 Abstract Several organic electroluminescent devices with different device structures were fabricated based on an organosamarium complex Sm(HFNH) 3 phen[HFNH ¼ 4, 4, 5, 5, 6, 6, 6-heptafluoro-1-(2-naphthyl)hexane-1, 3-dione; phen ¼ 1, 10-phenanthroline] as emitter. Their electroluminescent properties were investigated in detail. Although the devices with the optimal structure ITO/TPD (50 nm)/ Sm(HFNH) 3 phen (x wt%):CBP (50 nm)/BCP (20 nm)/AlQ (30 nm)/LiF (1 nm)/Al (200 nm) show high brightness (more than 400 cd/m 2 ) and high current efficiency (about 1 cd/A), there are emissions from CBP, BCP and even from AlQ existing in the electroluminescence (EL) spectra besides emission from Sm(HFNH) 3 phen. The reason to this was discussed. The device with the structure ITO/TPD (50 nm)/ Sm(HFNH) 3 phen (50 nm)/AlQ (30 nm)/LiF (1 nm)/Al (200 nm) exhibits the maximum brightness of 118 cd/m 2 and current efficiency of 0.029 cd/A, and shows emissions from AlQ and Sm(HFNH) 3 phen at high voltages. However, with the BCP hole-block layer added, the device [ITO/TPD (50 nm)/Sm(HFNH) 3 phen (50 nm)/BCP (20 nm)/AlQ (30 nm)/LiF (1 nm)/Al (200 nm)] exhibits pure Sm 3+ emission in the EL spectra even at high voltages, with the maximum current efficiency of 0.29 cd/A and brightness of 82 cd/m 2 . r 2006 Elsevier B.V. All rights reserved. Keywords: Samarium; Complex; Electroluminescence; Photoluminescence 1. Introduction Organic light-emitting diodes (OLEDs) have attracted intense interest from both academic and practical view- points since Tang’s pioneering work [1]. With the unique f-electronic configuration, organolanthanide luminescent complexes have been demonstrated to be new promising electroluminescent (EL) emitters due to their narrow emission with high color purity and internal quantum efficiency [2–9]. By selecting an appropriate organolantha- nide complex for the emitter, the EL spectrum in the entire visible region can be obtained. It is well known that OLEDs with trivalent europium [9] and terbium [3] ion complex as emitter exhibit bright red and green light, respectively. Other organolanthanide complexes [8], such as thulium, samarium and dysprosium complex have been used as emitter to obtain blue, orange and near white light, respectively. Among the organolanthanide complexes, the central lanthanide ions coordinated with b-diketone ligands give fascinating strong and high efficient fluores- cence, especially when b-diketone ligands with aromatic or fluorine substituents are present [10]. To our knowledge, fluorinated substituent introduced into the ligand increases the volatility of the complex, thus facilitating thin-film fabrication, and leads to improved thermal and oxidative stability and reduced concentration quenching of the luminescence [11]. In addition, fluorination can improve the photoluminescence (PL) and EL efficiency and enhance luminescence intensity [11]. In this paper, an organosamarium complex Sm(HFNH) 3 phen having b-diketone ligand with the polyfluorinated alkyl group and the long conjugate naphthyl group was synthesized. Several devices were ARTICLE IN PRESS www.elsevier.com/locate/jlumin 0022-2313/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jlumin.2006.01.258 Ã Corresponding author. Tel.: +86 431 5262127; fax: +86 431 5698041. E-mail address: hongjie@ciac.jl.cn (H. Zhang).