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:

Organic soluble DNA bearing two different fluorophores in the side chain was prepared by reacting purified DNA with the cationic molecules 9-(12-bromododecyl)-9H-carbazole and (E)-1-(4-(12-bromododecyloxy)styryl)pyrene in water. Two homopolymers (CzDNA and PyDNA) and random copolymers (CzDNA-co-PyDNA) were prepared successfully. The absorption and photoluminescence (PL) behavior of CzDNA-co-PyDNA with pyrene derivative concentrations was investigated. As reference, we employed a guest-host system and polymer blends using DNA homopolymers. The Förster energy transfer process was investigated in three different DNA systems. The DNA copolymer system showed much better energy transfer efficiency than the other DNA systems. The copolymers were mixed with 2-{2-[2-(4-diethylamino-phenyl)-vinyl]-6-methyl-pyran-4-ylidene}-malononitrile (DCM) at an optimum concentration. At low DCM concentration (0.3 wt %), undesired emissions were observed due to an incomplete energy transfer process from excited pyrene moieties. At high DCM concentration (5.0 wt %), red emissions were predominant; this is attributed to an efficient Förster energy transfer process. V V C 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: [5416][5417][5418][5419][5420][5421][5422][5423][5424][5425] 2009

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