Evaluation of Electrochromic Device Influenced by Various Formulation of Solid Polymer Electrolyte

Electrochromic devices (ECDs) using various polymer electrolyte membranes were evaluated in relation to their optical and electrochemical properties. It was found that the composition of polymer matrix markedly influence the transmittance change (ΔT) and stability of ECDs. The electrochromic (WO) and ion storage (Antimony tin oxide; ATO) layers were fabricated using dry deposition method. Moreover, various types of polymer matrix were used as the electrolyte, i.e., Liquid; PVdF-HFP (UV-0); PEGDMA-PEGMA/PVdF-HFP blended (UV-30); and PEGDMA-PEGMA solid (UV-100) membranes. ECDs using UV-30 exhibited good cyclability, in which the ΔT of 35% was maintained over 200 cycles. Furthermore, as a result of electrochemical analysis, ECD using UV-30 showed charge density of 34.43 mC/cm with low charge transfer resistance of 237.7 Ω at the interface between the coloration layer and electrolyte. Therefore, the solid polymer matrix electrolyte (UV-30) improved the electrochromic performance including stability due to excellent ion dissociation and ion mobility in the electrolyte.