Thermal and Spectral Stability of Fluorescent Copolymers Containing Tetraphenylthiophene-Quinoline Unit

Fluorescent alternative copolymers containing tetraphenylthiophene- quinoline (TP-Qu) moiety were synthesized from Friedlander reaction between o-aminoketone and acetyl groups. With the wholly aromatic-quinoline chain structure, the alternative donor-acceptor copolymers of PTPQu and PTPTPQu are rigid materials with high glass transitions (T-g = 245 and 295 degrees C, respectively) and with high thermal stability (with <= 2% weight loss at 500 degrees C). The multiple phenyl pendant rings inherited PTPQu and PTPTPQu copolymers with good solubility in common organic solvents, which facilitate the easy fabrications of light-emitting diode (LED) devices. CV study resulted in the reversible E-ox/(onset) values of 0.78 and 0.75 V for the PTPQu and PTPTPQu copolymers, respectively. With high quantum yields (Phi(F)s = 0.59 for PTPQu and 0.74 for PTPTPQu) in the film states, the two copolymers and their devices exhibit stable photoluminescence (PL) and electroluminescence (EL) spectra, respectively, on change of annealing temperatures to at least higher than 250 degrees C. After annealing at 250 degrees C (or 300 degrees C), no change was observed in the respective PL and EL spectra of PTPQu (or PTPTPQu) copolymers. The results indicate that alternative copolymers containing donor-acceptor TP-Qu unit are promising candidates for LEDs with high efficiency and spectral stability. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2059-2069, 2011