Bipolar host materials with carbazole and dipyridylamine groups showing high triplet energy for blue phosphorescent organic light emitting diodes. (June 2017)

• Record Type: Journal Article
• Authors: Park, So-Ra; Kim, Su-Mi; Kang, Ji-Ho; Lee, Ji-Hoon; Suh, Min Chul
• Is Part Of: Dyes and pigments. Volume 141(2017)
• Page Start: 217
• Page End: 224
• Publication Date: 2017-06
• Subjects: Organic light emitting diodes -- Blue host materials -- Highly efficient blue PHOLED -- Carbazole based host materials; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2017.02.014
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: A series of new bipolar host materials with carbazole and different number of dipyridyl amine groups were synthesized for blue phosphorescent organic light-emitting diodes (PHOLEDs). Especially, we applied dipyridyl amine to control the polarity as well as electron transporting property of the carbazole based host materials for comparison with the properties of 1, 3-di(9 H -carbazol-9-yl)benzene (mCP). As a result, all the carbazole based host materials with dipyridyl amine moieties showed very high triplet energies (>2.9 eV) as well as wide band gap (>3.5 eV). Thus, the blue phosphorescent devices employing those materials with bis(4, 6-difluorophenyl pyridinato- N, C2 )picolinato-iridium (III) (FIrpic) as a dopant and we obtained moderately high external quantum efficiency (EQE) up to 21.6% with N -(3, 5-di( 9H -carbazol-9-yl)phenyl)- N -(pyridin-2-yl)pyridin-2-amine (DCPPy ). Graphical abstract: Highlights: Highly efficient blue PHOLED devices fabricated with new host materials. Bipolar properties originated from carbazole and dipyridyl amine moieties. High triplet energy greater than 2.9 eV. Higher thermal stability than that of common host material like mCP.