Temperature effect on photoluminescent properties of red light-emitting materials based on Ru(II)-chelated complexes

Abstract

A new class of silicon-based copolymers containing Ru(II)-chelated complexes for new red light-emitting materials was developed by well-known Heck reaction between distyrylsilane monomer and the difunctionalized metal-chelated complexes. Ru(II)-chelated copolymers I and II showed one strong band approximately 265-289 nm for ligand units, one strong absorption band approximately 386-392 nm for pi-conjugated backbones, and a broad shoulder metal-to-ligand charge transfer band approximately 460-465 nm. Ru(II)-chelated polymers exhibited a negligibly broad band approximately 495-500 nm in the greenish blue region and one/or two strong bands in the red region at room temperature. The photoluminescent (PL) properties of all materials as a function of temperatures were also investigated. With a photoexcitation wavelength of 325 nm at various temperatures, their PL intensity approximately 673-675 nm increased gradually with decreasing temperature, due to the restraint of the thermal relaxation decay. (C) 2002 Elsevier Science B.V. All rights reserved.