A novel near-infrared-emitting cyclometalated platinum (II) complex with donor-acceptor-acceptor chromophores

A novel near-infrared-emitting cyclometalated platinum (II) complex of (TPA-BT-Q)Ptpic with a donor-acceptor-acceptor (D-A-A) chromophores was synthesized and characterized, in which the TPA-BT-Q unit is a cyclometalated ligand of N,N-di(4-octyloxyphenyl)-4-(7-(quinolin-2-yl)-benzo[c][1,2,5]thiadiazol-4-yl)-phenylamine and pic is picolinate anion. Its optophysical, electrochemical and electroluminescent characteristics were primarily studied. An intense UV-vis absorption peak at 540 nm and a strong near-infrared emission peak at 759 nm were observed for (TPA-BT-Q)Ptpic in dichloromethane. Using (TPA-BT-Q)Ptpic as a single dopant and a blend of poly(vinylcarbazole) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole as a host matrix, the single-emissive-layer polymer light-emitting devices exhibited a near-infrared emission peaked at 760 nm with the maximum external quantum efficiency of 0.12% at 16.6 mA cm(-2) and a radiance intensity of 112 mu W cm(-2) at 11.7 mA cm(-2) at the doping concentrations of 2.0 wt%. This work provides an efficient approach to realize near-infrared electrophosphorescent emission with high radiance intensity by employing platinum (II) complex with the D-A-A structure. (C) 2014 Elsevier Ltd. All rights reserved.