Dynamic structural colour using vanadium dioxide thin films

Abstract

A thin film stack consisting of layers of Indium Tin Oxide (ITO) with an intermediate Vanadium Oxide (VO2) layer on an optically thick silver film has been investigated for dynamic structural colour. The structure benefits from the phase change properties of VO2. Compared with other phase change materials, such as Germanium Antimony Telluride (GST), VO2 can be offered as a lower power consumption alternative. It has been overlooked in the visible spectral range due to its smaller refractive index change below 700 nm. We demonstrate that the sensitivity of the visible reflectance spectrum to the change in phase of a 30 nm VO2 layer is increased after it is incorporated in a thin film stack, with performance comparable to other phase change materials. The extent to which dynamic tuning of the reflectance spectra of ITO-VO2-ITO-Ag thin film stacks can be exploited for colour switching is reported, with approximately 25% change in reflectance demonstrated at 550 nm. Inclusion of a top ITO layer is also shown to improve the chromaticity change on phase transition.

Effect of a CdSe Layer on the Thermo- and Photochromic Properties of MoO3 Thin Films Deposited by Physical Vapor Deposition

“…Among chromogenic samples, certain transition-metal oxides, for instance, vanadium dioxide (VO 2 ), tungsten trioxide (WO 3 ), and molybdenum trioxide (MoO 3 ), are known to possess photo-, thermo-, or electrochromic properties. In some cases, more than one of these properties are presented simultaneously − with great potential for use in several technological applications due to their outstanding physical and chemical properties. − ,− …”

Optical Janus Effect in Large Area Multilayer Plasmonic Films

“…This is the first time the Janus effect has been demonstrated using continuous metal films with only as the dielectric material. Given the potential applications of the device, future developments could include replacing the rigid substrate with a flexible polymer or introducing a degree of tunability through the incorporation of layers of tunable materials such as liquid crystals [ 34 ] or phase change materials, [ 35 ] substituting the absorbing layer by electrically conductive films , [ 19,36 ] or via mechanical deformation. [ 37 ]…”

Stimuli-Responsive Phase Change Materials: Optical and Optoelectronic Applications

“…Other stacked non-structured multilayers, among which one is made of VO 2 , can generate different and variable colors, as reported by Wilson et al [ 24 ].…”

“… ( a ) Insulator to metal phase-change transition in VO 2 [ 23 ]; ( b ) variation in the visible range of the real part of the refractive index of VO 2 upon phase transition [ 24 ]; ( c ) variation in the visible range of the imaginary ( k ) part of the refractive index of VO 2 upon phase transition [ 24 ]. Reproduced from Refs.…”