Transmission Spectra of All Inorganic Solid State Electrochromic Multilayers: A Simulation and Experimental Study

The all inorganic solid state electrochromic multilayers, comprising the bleached layer of WO₃, colored layer of Li_xWO_y, ion-conductive layer of Ta₂O₅, ion-storage layer of Ni_xO and anti-reflection layer of SiO₂, were synthesized by reactive magnetron co-sputtering on the glass substrate pre-coated with indium-tin-oxide (ITO) layer.Its optical properties, including the refractive index and extinction coefficient, were mathematically modeled, theoretically analyzed, numerically simulated with TFCalc software and experimentally evaluated with ellipsometry.The influence of the anti-reflection SiO₂ layer, 110 nm in thickness, on the enhancement of bleached state transmittance and electrochromic behavior was investigated.The results show that the calculated change in transmittance, 66.9%, was higher than that of 56.7% measured at 550 nm and ±5 V, and that the anti-reflection layer further increased the change in transmittance to 77.7%.