Hole transport triphenylamine-azomethine conjugated system: Synthesis and optical, photoluminescence, and electrochemical properties

A series of six conjugated aromatic polyazomethines has been obtained by high-temperature solution polycondensation of diformyltriphenylamine with different primary aromatic diamines. The structures of polymers are characterized by means FTIR, ¹H NMR, and ¹³C NMR spectroscopy and elemental analysis; the results show an agreement with the proposed structure. Polyazomethines emitted blue or blue-green light. Relative PL intensity of the polymers investigated in chloroform solution was found about 0.30%, while for doped ones it was about 20% in relation to 9,10-diphenylanthracene. Additionally, the photoluminescence spectra of the polyazomethines in polymer blend with poly(methyl methacrylate) (PMMA) have also been described. The lowest optical band gap value at 2.41 eV was detected. Polymers were investigated also by cyclic voltametry and differential pulse voltammetry in dichloromethane. An influence of different types of dopants, i.e., methanesulfohic acid (MSA), camphorsulfonic acid (CSA), m-cresol (MC), p-chlorophenol (PC), and p-pentadecylphenol (PDP), on absorption and emission wavelengths was investigated.