Improved performance and stability of solid state electrochromic devices with eco-friendly chitosan-based electrolytes

Development of chitosan (Ch)-based green solid polymer electrolyte was attained with addition of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) using solvent casting method for electrochromic device. In the electrochromic device configuration, poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3-methylthiophene) (PMeT) were used as counter polymer electrodes. The effect of chitosan/PEDOT:PSS-based electrolyte on PEDOT/PMeT-based electrochromic devices was evaluated. In order to deeply compare all electrochromic devices, electrochemical, transmittance, electrochemical impedance measurements were used. PEDOT:PSS can assist both electronic and ionic conduction leading to reduced charge transfer resistance and better electrochromic performance. Presented electrochromic device with use of PEDOT:PSS displayed higher optical modulation (20.6%/ +/- 1 V; 32.2%/ +/- 2 V at 650 nm, faster response times (coloration time (t(c): 0.1 s/ +/- 1 V, 0.24 s/ +/- 2 V and bleaching time (t(b)): 0.11 s/ +/- 1 V, 0.52 s/ +/- 2 V)). These results signify that the addition of PEDOT:PSS to electrolyte is useful for improved electrochromic characteristics as the electrolyte for the fabrication of electrochromic device.