Nickel oxide-based photochromic composite films

Abstract

Nickel oxide-based photochromic composite films were fabricated by combining nickel nitrate in methanol solution with a transparent urethane resin. The resulting nickel oxide-based composite film showed a reversible photochromic property that was similar to the electrochromic property in nickel oxide-based films. IR spectra revealed that the valence state of nickel in the composite films changed from "+3" to "+2" under UV irradiation. The Ni-based particles dispersed in the films had sizes of 40100 nm.