Thermal and spectral stability of fluorescent copolymers containing tetraphenylthiophene‐quinoline unit

Fluorescent alternative copolymers containing tetraphenylthiophene‐quinoline (TP‐Qu) moiety were synthesized from Friedländer 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 (Tg = 245 and 295 °C, respectively) and with high thermal stability (with ≤2% weight loss at 500 °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 Eox/onset values of 0.78 and 0.75 V for the PTPQu and PTPTPQu copolymers, respectively. With high quantum yields (ϕFs, = 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 °C. After annealing at 250 °C (or 300 °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.