Synthesis and characterization of unsymmetrically branched alkyl chains carbazole-based polymer

This work introduces a modified poly[N- dodecanyl-2,7-carbazole-alt-5,5-(4’,7’-di -2-thienyl -(N,N’- dodecanyl -6, 6’- isoindigo))] (PCDTID) with the unsymmetrically branched N-alkyl chain, which is as poly[N -(2-hexyldecyl)-2,7-carbazole -alt -5, 5-(4’,7’-di -2-thienyl-N,N’ -(2-hexyldecyl) -6,6’- isoindigo)] (P1). The synthesis of P1 involves Suzuki’s coupling reactions. Suitable analysis techniques have been used to study the chemical, physical, thermal, optical and electrochemical properties of P1. The analysis results show that P1 possesses higher HOMO and LUMO energy levels than the previously reported PCDTID, which have been narrowing the electrochemical band gap down to 1.37 eV. However, the P1 experiences 5% thermal degradation at 393 °C, which is relatively less favourable than the PCDTID. Hence, the replacement of the symmetrically branched alkyl chains of PCDTID with unsymmetrically branched alkyl chains results in both improvement and drawback on the characteristics of the polymer.