Evaluation of optical performance due to coating [formula omitted], [formula omitted], [formula omitted] and [formula omitted] nano-layer on a commercial [formula omitted]-based switchable window: A simulation approach

Abstract

Most of Switchable Windows (SWs) in opaque status reduce the Light Transmittance Coefficient (LTC) especially in visible range of wavelengths and this causes to use more energy for compensating the lighting demands. In this study, four metals; Au, Ag, Pr And Yb; were separately coated on a Switchable Window Sensitive to Electron Density (SWSED) which are a cheap and easy to build type of the SWs and the changes of the LTC was simulated in both opaque and bleached status and the results compared with the base SWSED. Based on the results of the bleached status, using of the metals except for Yb improved the LTC in all wavelengths. Moreover, in the opaque status, metals with the high light-scattering property including Au and Ag significantly increased the LTC in the visible range in all thicknesses but they also increased the LTC in the ultraviolet and infrared ranges. The results showed that Pr with the up-conversion property improved the LTC in all wavelengths less than Au and Ag whereas Yb as a metal with the down-conversion property decreased the LTC in all wavelengths. Considering a multi-objective optimization function, based on increasing the LTC in the visible range and decreasing the LTC in other wavelengths, showed that a layer of Pr with the thickness of 50 nm coated on a layer of WO3 with the thickness of 569 nm can increase the LTC averagely about 4.93% for the SWSED in the opaque status.