Moriomoto Takuro, Oka Ryohei, Minagawa Kohei, Masui Toshiyuki
Department of Engineering, Graduate School of Sustainability Science, Tottori University 4-101, Koyama-cho Minami Tottori 680-8552 Japan.
Field of Advanced Ceramics, Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa Nagoya 466-8555 Japan
RSC Adv. 2022 Jun 6;12(26):16570-16575. doi: 10.1039/d2ra02483g. eCollection 2022 Jun 1.
Gd-doped cerium vanadates, Ce Gd VO (0 ≤ ≤ 0.30), were synthesized as near-infrared (NIR) reflective black pigments by a conventional solid-state reaction method. Crystal structure, particle size, optical properties, and color of the samples were characterized. The Ce Gd VO (0 ≤ ≤ 0.30) samples were obtained in a single-phase form and the lattice volume decreased with increasing Gd concentration. Optical absorption below 630 nm was observed in all samples, which corresponded to the charge-transfer transition between Ce and V orbitals. The absorption spectrum of Ce Gd VO was shifted to the longer wavelength side as the Gd content increased, because of the increase in the crystal field around V due to the lattice shrinkage. As a result, the sample color gradually changed from dark brown to black with increasing Gd content. Among the samples synthesized in this study, CeGdVO absorbed visible light with wavelengths shorter than 650 nm and exhibited the darkest color. Furthermore, this black pigment showed a sufficient NIR reflectance value ( = 66.3%), which was higher than those of the commercially available products ( < 50%).
通过传统的固态反应法合成了掺钆钒酸铈（Ce₁₋ₓGdₓVO₄，0 ≤ x ≤ 0.30）作为近红外（NIR）反射黑色颜料。对样品的晶体结构、粒径、光学性能和颜色进行了表征。Ce₁₋ₓGdₓVO₄（0 ≤ x ≤ 0.30）样品以单相形式获得，晶格体积随钆浓度的增加而减小。在所有样品中均观察到630 nm以下的光吸收，这对应于铈和钒轨道之间的电荷转移跃迁。由于晶格收缩导致钒周围晶体场增加，Ce₁₋ₓGdₓVO₄的吸收光谱随着钆含量的增加向更长波长方向移动。结果，随着钆含量的增加，样品颜色逐渐从深棕色变为黑色。在本研究合成的样品中，CeGdVO吸收波长小于650 nm的可见光并呈现出最深的颜色。此外，这种黑色颜料显示出足够的近红外反射率值（ρ = 66.3%），高于市售产品（ρ < 50%）。
