Organic soluble deoxyribonucleic acid (DNA) bearing carbazole moieties and its blend with phosphorescent Ir(III) complexes

Abstract

A functionalized deoxyribonucleic acid (Cz-DNA) was prepared with carbazolyl ammonium lipid as a triplet host material for phosphorescent material system. It is soluble in organic solvents, which facilitates the sample preparation for the absorption and luminescent properties in solid states. A highly soluble iridium complex, Ir(Cz-ppy) 3 with carbazolyl-substituted 2-phenylpyridine ligands was employed for studying the phosphorescence in Cz-DNA. There is a good overlap between the photoluminescence spectrum of Cz-DNA and the metal-to-ligand charge transfer (MLCT) absorption bands of the iridium complex. This overlap enables efficient energy transfer from the excited state in the host to the MLCT band of Ir(Cz-ppy) 3 . In addition, photoluminescence quantum yield of Cz-DNA was found to be rela-tively larger than the copolymer (PCzSt) with vinylcarbazole and styrene. Thus, Cz-DNA was employed as a triplet host material for fabricating multilayered electrophosphorescence devices via modification of its property by doping 5,4-tert-butylhexyl-1,3,4oxadiazole (PBD). After doping 30 wt % PBD and 10 wt % Ir(Czppy) 3 into Cz-DNA, we achieved much improvement in electron injection/transport from an adjacent carrier transport layer, resulting in much improved device performances. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48:

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