Characteristics Analysis of Color Glass for BIPV Manufactured Using R.F Magnetron Sputtering Method

Building-integrated photovoltaics (BIPV) extend the traditional role of buildings by enabling on-site power generation while simultaneously addressing architectural and aesthetic requirements. In this context, colored glass is no longer a purely decorative element but a functional component that directly influences optical transmittance, color perception, and electrical performance. Despite increasing interest in colored BIPV modules, systematic quantitative analyses of color dispersion and optical property variation within the same color family remain limited. In this study, colored glass for BIPV applications was fabricated by depositing thin films with thicknesses below 100 nm onto indium tin oxide (ITO)-coated glass substrates using radio-frequency (R.F.) magnetron sputtering with various metal targets, including MoO₃, WO₃, Si, TiN, and SiO₂. The fabricated specimens were categorized into red, yellow, and blue color families and systematically analyzed in terms of optical transmittance, sheet resistance, and quantitative colorimetric properties. Color characteristics were evaluated using CIELAB coordinates (L*, a*, b*) and CIE 1931 chromaticity coordinates (x, y), while color differences (ΔE*ab) were calculated relative to a MoO₃/WO₃ reference specimen. The chromaticity distributions revealed continuous and material-dependent color-shift trajectories within the CIE 1931 color space rather than random dispersion. Oxide-based coatings exhibited gradual shifts toward the yellow region with relatively high lightness, whereas TiN-based coatings showed distinct migration toward the blue region accompanied by reduced lightness. These color shifts were consistently correlated with changes in spectral transmittance and electrical resistance induced by variations in sputtering targets and deposition conditions. The results demonstrate that color variation in sputter-deposited BIPV glass arises from systematic optical responses across the visible spectrum rather than from isolated wavelength-selective absorption. This study provides a quantitative framework for comparing color realization characteristics within the same color family and offers practical guidance for material selection and process optimization in the design of colored glass for BIPV applications.