Bromophenoxy Substitution Effect on Thermal and Opto‐Electronic Properties of Triphenylamine‐Based Co‐polyimides

Abstract

AbstractThe present study reported the synthesis of a series of 4,4’diamino‐(4’’‐p‐bromophenoxy)triphenylamine diamine 2 based co‐polyimides (Br‐TPA co‐PIs (A−D))obtained via polycondensation of 2 with a series of dianhydrides. The nucleophilic N‐arylation of the 4‐(4‐bromophenoxy)benzenamine followed by catalytic reduction was used to obtain 2. The synthesized Br‐TPA coPIs were characterized by CHN elemental, and FTIR spectral analysis. The optical and redox active properties were examined by the ultraviolet/visible (UV/vis) absorption, photoluminescence emission spectral analysis and cyclic voltammetry respectively. From which it is obvious that Br‐TPA coPIs are optical transparent, and deep blue light emissive in the range 465–472 nm with a quantum efficiency of 4.6–7.3 %. The lifetime decay was calculated from the time correlation single photon counting (TCSPC) and found in the range 11.7‐12.9 nS. The evaluation of thermal properties via thermogravimetric analysis (TGA) revealed excellent thermal stability of synthesized materials in the range 426–476 °C. The excellent thermal properties, appreciable processability, shallow HOMO levels (−4.70 eV), low onset oxidation (E onset=0.296 V) and long‐lived excited states (12.94 nS decay time) evidently depicted their optoelectronic character, suggesting their use as efficient light emitting layer in light emitting diiodes.