Preparation and near-infrared reflective characterization of Cu-doped sodium zincophosphate

Cu-doped sodium zincophosphate [NaZn1−x(Cu)xPO4; x=0.05, 0.10, 0.15, and 0.20] powders were prepared by a coprecipitation method for the use as a dark heat-reflective material. The weighted average of the reflectance was calculated according to the reflectivity data measured using a UV–visible and near-infrared spectrophotometer. The measurement wavelength region was 380–2500 nm. The visible and near-infrared reflective properties of NaZn1−x(Cu)xPO4 doped with different amounts of Cu at varied calcination temperatures were investigated. NaZn(Cu)PO4 was found to be the main phase that crystallized in a monoclinic system of NaZn0.9(Cu)0.1PO4 at 800 °C. The sample of NaZn0.9(Cu)0.1PO4 was black in the visible region because of its high absorption, and its weighted average reflectance reached 51% in the near-infrared region. As a result, NaZn1−x(Cu)xPO4 has potential applications as a dark heat-reflective material.