Novel electrochromic and infrared emissivity modulation films based on poly(carbazoyltriphenylamine) and poly(carbazoyltriphenylamine-thiophene)

Synthesis and characterizations of novel conducting polymer film based on poly(carbazoyltriphenylamine) (poly(CBZ-TPA)) were studied. Additionally, copolymer film based on CBZ-TPA and thiophene (Th) was also obtained by electrochemical polymerization. Electrochromic properties of poly(CBZ-TPA) and poly(CBZ-TPA-Th) films were investigated by cyclic voltammetry and double step potential chronoamperometry. Optical properties of the two films were characterized by UV–vis spectrophotometer and FT-IR spectrometer. Different colors of poly(CBZ-TPA) film were achieved, which exhibits as camel gray (at −0.5 V), light gray (at 0 V) and army green (at 1.6 V). The maximum UV–vis absorption difference of poly(CBZ-TPA) film is about 15.83% in the visible region when applied with the voltage between 0 V and 1.6 V, and the coloring and bleaching time are 1.8 s and 1.0 s, respectively. The biggest different average IR-emissivity modulation of poly(CBZ-TPA) film is 0.37 in the wavelength regions of 8–14 μm. The copolymerization film of thiophene with CBZ-TPA has a distinct effect on the electrochromic performance of poly(CBZ-TPA) film. Compared with poly(CBZ-TPA) film, poly(CBZ-TPA-Th) film shows different colors, which exhibits as maize-yellow (at −0.5 V), milk white (at 0 V) and dark green (at 1.4 V). The maximum UV–vis absorption difference of poly(CBZ-TPA-Th) film is about 23.30% in the visible region between 0 V and 1.4 V, but it has a slower response speed (coloring and bleaching time are 3.0 s and 4.0 s, respectively). However, the biggest different average IR-emissivity modulation of poly(CBZ-TPA-Th) film reaches up to 0.41 in the wavelength regions of 8–14 μm compared to that of poly(CBZ-TPA) film.