Layer-by-layer versus copolymer: Opto-electrochemical properties of 1,3,5-Tris(N-carbazolyl)benzene and EDOT based polymers

Polymer deposition directly from monomer(s) is important for different applications in wide fields. Layer-by-layer thin film PTCB-layer-PEDOT was deposited by the successive electrochemical polymerization of 1,3,5-tris(N-carbazolyl)benzene (TCB) and 3,4-ethylenedioxythiophene (EDOT) using 0.1 M TBAPF6 in CH2Cl2. For comparison purpose, copolymers P(TCB-co-EDOT) along with corresponding homopolymers (PTCB and PEDOT) were prepared systematically by electrochemical polymerization under identical conditions. A systematic study of cyclic voltammetry (CV), stability, impedance spectroscopy, spectroelectrochemistry and electrochromic properties of all the polymers are reported where applicable. The results revealed that CV and spectroelectrochemistry could be a powerful technique to characterize these polymer films. In contrast to layer-by-layer polymer, copolymer exhibits new properties compared to the corresponding homopolymers. Further, a series of copolymers P(TCB-co-EDOT) were prepared from the different molar ratio of monomers and we achieved the band gap control in the copolymers.