Study of dual electrochromic devices based on polyaniline and poly (3-hexylthiophene) thin films

Polyaniline (PANI) and poly (3-hexylthiophene) (P3HT) are conducting polymers exhibiting electrochromic properties. In this work both polymers were studied in single and dual electrochromic devices (ECDs). PANI and P3HT are complementary electrochromic polymers, both films in its redox process in a dual device are clarified and obscured at the same time. This color change provided a significant difference in optical transmittance in a dual ECD. Both polymers were synthesized by chemical method. The effect of deposit method of P3HT films in the single and dual ECDs was studied. A viscous polymeric electrolyte (PE) of polymethyl methacrylate and lithium perchlorate dissolved in ethylene and propylene carbonates was used in ECDs. The architectural design of single and dual device was GLASS/ITO/PANI or P3HT/PE/ITO/GLASS and GLASS/ITO/PANI/PE/P3HT/ITO/GLASS, respectively. The electrochromic devices were constructed under environmental conditions. Transmittance spectra of colored and bleached states, and kinetic optical transmittance curves at 550 nm of single and dual ECDs were obtained. Dual P3HT-PANI-based ECDs exhibited a faster rate of transmittance change, higher stability and higher transmittance change compared with the single devices. The difference in transmittance depended of the deposit technique of the films. An optical contrast of 57 % was obtained at 550 nm.