Electrochromic properties of novel chalcones containing triphenylamine moiety

• Novel chalcones containing triphenylamine moiety were synthesized by Aldol reaction.
• Electrochromic devices were fabricated by using propylene carbonate solutions.
• TPA-chalcones showed excellent electrochromic and rapid coloring/bleaching properties.
• This work suggests the way to investigating electrochromism of TPA derivatives.

A series of novel electrochromic chalcones containing triphenylamine units were synthesized by Aldol reaction and characterized by NMR, IR and MS. Their optical, electrochemical properties were investigated using UV–vis, photoluminescence spectra and cyclic voltammetry. The molecular orbital energy levels and excitation energies were calculated by quantum chemical calculation. It was found that the fluorescence intensity is decreasing with formation of charge-transfer state. The existence of electron donating group on triphenylamine unites caused a significant bathochromic shift of the UV absorption maximum and increased EHOMO and ELUMO. The electrochromic property of the synthesized compounds was studied by spectroelectrochemical experiments. The results showed that the chalcones containing triphenylamine moiety presented good electrochromic stability, with a color change from yellow to blue as applied potentials ranging from 0.0 to 2.8 V. The coloring and bleaching time was in the range of 2.9–4.2 s and 1.7–3.3 s, respectively.

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