Low temperature synthesis of NIR reflecting bismuth doped cerium oxide yellow nano-pigments

High Near-Infrared Reflective Zn1–xAxWO4 Pigments with Various Hues Facilely Fabricated by Tuning Doped Transition Metal Ions (A = Co, Mn, and Fe)

“…The near-infrared reflectance and spectral irradiance in a range of 700−2500 nm are clearly shown in Figure 7; it can be obviously observed in Figure 7a that the ZnWO 4 pigment has the highest nearinfrared reflectance of 96.66%. When the chromophore ions have replaced the Zn 2+ ion, the near-infrared reflectance in a wavelength range of 1300−2100 nm has slightly decreased; however, the colorful pigments still keep a relatively higher near-infrared reflectance compared with the commonly reported near-infrared reflectance pigments, such as the specific Ce 0.8 Bi 0.2 O 2 yellow pigment (R = 87.31%), 5 Sr 0.6 Eu 0.4 CuSi 4 O 10+σ blue pigment (R = 57.07%), 39 La-Fe 0.7 Al 0.3 O 3 brown pigment (R = 52.50%), and Bi 0.6 Cr 0.4 PO 4 pale green pigment (R = 84.63%). 40,41 There is a difference in the near-infrared reflectance between the Mn 2+ -doped pigment and Co 2+ -doped pigment; this may be the reason for the absorbed radiance energy of the Zn 0.9 Co 0.1 WO 4 pigment that is located in the NIR region.…”

“…In recent years, inorganic pigments with aesthetic features, nontoxic elements, and high near-infrared reflectance have attracted wide attention from researchers. , Inorganic pigments are more stable than organic pigments and are quite suitable for utilization in cooling buildings, which resulted from the absorption of solar radiation in the visible region (380–780 nm) and near-infrared region (700–2500 nm), − and the near-infrared light is not only valuable for the inorganic pigments, but also they can be applied in the field of bioimaging. − Because of the limitation of prerequisite light absorption for colors, highly near-infrared reflective inorganic pigments are more conducive to reducing the absorption of solar energy …”

“…10 Moreover, charge transfer between two atoms in a host compound was also an inducing factor of colors. 11,12 Notably, ZnWO 4 possessed irregular octahedral geometry and Zn 2+ (3d 10 ) can be possibly substituted by some transition metal ions, such as Mn 2+ (3d 5 ), Fe 3+ (3d 5 ), Co 2+ (3d 7 ), Ni 2+ (3d 8 ), and Cu 2+ (3d 9 ), which will lead to the formation of different colors. 13,14 Ni 2+ is adverse to environment protection, and Cu 2+ is relatively expensive; accordingly, both of them are ignored.…”

High Near-Infrared Reflectance Orange Pigments of Fe-Doped La2W2O9: Preparation, Characterization, and Energy Consumption Simulation

“…It is well known that 5% of the solar radiation is distributed in the ultraviolet region (UV, 200–400 nm), 43% in the visible region (vis, 400–700 nm), and 52% in the near-infrared (NIR) region (700–2500 nm). − In view of this, the heat island effect can be effectively alleviated by the development of a pigment with high NIR reflectance and applying it to the cool coatings. At present, inorganic pigments with good chemical and thermal environmental stabilities are superior to organic pigments .…”

WITHDRAWN: Synthesizing and Characterizing the Hybrid Pigment Fe 0.7 Cr1.3 O3 With High NIR Reflectance for Sustainable Energy Saving Applications

“…These cool colors could be applied as coatings on the house roofs and effectively re ect the sunlight's infrared part. The cool pigments play a prominent role in these cool coatings [5,6]. Many researchers have focused on these pigments during the last years to improve their IR re ectance property [7][8][9][10][11].…”