Self-Cleaning Transparent Heat Mirror with a Plasma Polymer Fluorocarbon Thin Film Fabricated by a Continuous Roll-to-Roll Sputtering Process

Abstract

This paper proposes a novel self-cleaning transparent heat mirror (SC-THM) produced by depositing a plasma polymer fluorocarbon thin film on a silver-and-SiN _x multilayer structure fabricated by continuous roll-to-roll sputtering. The optimal structure and the thickness of each thin film of three-layer and five-layer SC-THMs were derived from optical simulation. In the five-layer SC-THM, the visible light transmittance was 60.67% at a wavelength of 406 nm and the infrared (IR) transmittance was 6.86% at a 1000 nm wavelength and 2.50% at a 1500 nm wavelength. The value of the performance parameter T_vis/ T_sol was 1.70. The SC-THM exhibited self-cleaning with a very good water repellency of more than 111°, achieved by applying a low-surface-energy fluorocarbon thin film to the top layer. This study successfully demonstrated the IR blocking properties of an SC-THM through IR reflection and IR irradiation experiments.