Reflectance and Color Tuning in TiO2-CuO Nanoparticle Composition Mixing

Abstract

Energy consumption for building cooling is directly related to incident solar radiation. Therefore, solutions of high reflectivity, while keeping color comfort, are being actively researched. Here, finite-difference time-domain (FDTD) simulations were used to investigate the influence of nanoparticle and core–shell additives on coating reflection and color. Different TiO2 and CuO nanoparticle mixings were tested, with relative concentrations varying from 0 to 20% of each on acrylic. The same compounds were used to define core–shells with a varied inner radius (0–30 nm) for both TiO2 and CuO as the core and shell. The numerical simulations demonstrate that mixing CuO with TiO2 enables dark colors while maintaining the overall reflectance. The reflectance results for the core–shell structure are comparable with those of the nanoparticles when CuO is the core, while a more pronounced color change is originated when CuO is the shell.