Synthesis, electrochromic, halochromic and electro-optical properties of polyazomethines with a carbazole core and triarylamine units serving as functional groups?

Journal of Materials Chemistry C Pub Date: 2015-02-17 DOI: 10.1039/C4TC02400A

Abstract

A series of aromatic polyazomethines (PAMs) were prepared via direct polycondensation from 9-(2-ethylhexyl)-carbazole-3,6-dicarboxaldehyde and six different types of diamine containing triarylamines. The PAMs displayed good solubility in many organic solvents, such as tetrahydrofuran (THF), chloroform (CHCl3) and N,N-dimethylformamide (DMF) which was beneficial for polymer film formation via spin coating, and exhibited outstanding thermal stability. These PAMs exhibited blue-green photoluminescence around 405–520 nm with a quantum yield of up to 48% in a dichloromethane (CH2Cl2) solution. They exhibited halochromic properties with a color change from yellow to red, accompanied by fluorescence quenching after HCl-doping. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the PAMs were determined from cyclic voltammograms to be ?5.01 to ?4.88 eV and ?2.15 to ?2.11 eV, respectively. The PAMs films not only had good electrochromic properties with high coloration efficiency, but also generated photovoltage and photocurrent under simulated solar radiation.

Graphical abstract: Synthesis, electrochromic, halochromic and electro-optical properties of polyazomethines with a carbazole core and triarylamine units serving as functional groups
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