Electrochemical Analysis of Optical Switchable Filter with a NiO Thin Film for High-Performance Incubators

Abstract

An optical switchable light filter was fabricated from all solid-state materials of ITO/W-Ir-O/Ta2O5/NiO/ITO for use in preterm infant incubators. The materials were fabricated by magnetron sputtering. The as-prepared NiO film was stored in a thermostat/humidistat bath to create the nickel hydroxide, and its basic properties were also investigated by electrochemical and optical analysis. The filter also contained a W-Ir-O thin film, because the widely used WO3 thin film shows an unsuitable electrochromic color change to dark blue. The W-Ir-O thin film did not absorb the longer wavelengths in the visible range, which is required for incubators. The filter changed between pale yellow and dark yellow when a voltage was applied. The fabrication of filters with a suitable color change for incubators requires further investigation.