Synthesis of novel light-emitting polymers and application in diodes with red phosphorescent cyclometalated iridium complex

Novel carbazole- and triarylamine-containing polymers, poly[N-(2-ethylhexyl)carbazole-alt-aniline] (PECA), poly[N-(2-ethylhexyloxy-phenyl)carbazole-alt-aniline] (PEPCA), poly[N-(2-ethylhexyl) carbazole-alt-N-(4-aminophenyl)carbazole] (PECAC) and poly[N-(2ethylhexyloxy-phenyl)carbazole-alt-N-(4-aminophenyl)carbazole] (PEPCAC) showed good physical, optical, and electronic properties. Study on electrochemical properties of these polymers revealed that the band gap and HOMO energy were 2.91 and -5.19 eV for PECA, 3.14 and -5.10 eV for PEPCA, 2.97 and -5.01 eV for PECAC, and 3.25 and -5.17 eV for PEPCAC. Results proved that four polymers could be used as hole-transporting and host-matrix materials for phosphorescent PLEDs. Electrophosphorescent devices were fabricated by using a red phosphorescent iridium complex (IR-PIQCH) as a guest and four polymers as hosts, and the device performance was evaluated in terms of polymer structure, EL emission spectrum, luminance, driving voltage, and color coordinate. (C) 2007 Elsevier B.V. All rights reserved.