Pink NIR pigment based on Cr-doped SrSnO3

Abstract

Perovskite pigments with SrCrxSn1-xO3- (x = 0.025, 0.05, 0.1, 0.2, 0.3) composition were prepared by a solid-state reaction, suspension mixing of materials, and mechanochemical activation of initial reagents with calcination at high temperature. Results of thermal analysis show the effectivity of mechanochemical activation of reaction mixture that shifts the reaction course to lower temperature. Solid solution of SrSn0.975Cr0.025O3- was prepared at temperature 1200 °C. The optimal composition for synthesis of the intense red-pink powder is SrSn0.975Cr0.025O3- (L*/a*/b* = 36.34/14.21./1.12). Red-pink colour of the pigments is explained in terms of crystal field theory. The partial substitution of tin ions by chromium ions leads to formation of the optical absorption bands corresponding to the O2p-Cr3d charge transfer transitions. Pigment is distinguished by good chemical stability in a molten ceramic glaze and high value of solar reflectance in the near infrared region of light (R*  61%).

Influence of Zirconium (Zr4+) Substitution on the Crystal Structure and Optical and Dielectric Properties of Sr0.8Mg0.2(Sn1–xZrx)O3 Ceramics

“…Hydrothermal syntheses with microwave assistance method have also been carried out for several compositions . Microwave dielectric ceramics with right relative permittivity (ε r ), high quality factor ( Q × f ) values, and approximately zero temperature coefficient of resonant frequency have been extensively studied over the past few decades because they are essential components for microwave substrates, resonators, oscillators, and so on. − In addition, with the rapid development of wireless communication and the huge amount of information discovery since the start of the 21 st century, there are new and higher requirements for microwave dielectric ceramics. ,, The focus of academic attention has shifted more and more toward investigating the upper limit of dielectric properties and looking for new low-loss candidates to meet emerging requirements. Based on this, we previously systematically investigated the synthesis of Sr 3 Ti 2 O 7 bulk ceramics and obtained excellent microwave dielectric properties (ε r = 63, Q × f = 84,000 GHz, and τ f = 293 ppm/°C) .…”

“…Semiconductor sensors (for humidity and gases), energy storage, and barrier layer capacitors have been reported as applications of stannates. − Stannate synthesis routes are especially interesting because of their importance. Stannates have already been successfully synthesized using a variety of techniques, i.e., high-temperature solid-state reactions of M­(NO 3 ) 2 /SnO 2 or MCO 3 /SnO 2 powder mixtures at different temperatures, i.e., 1000–1450 °C. − In addition to these ceramic preparation methods, those stannates can also be made by using sol–gel processes or by thermally decomposing oxalates . However, the temperatures needed for these two alternate methods are 800 or 1000 °C, respectively.…”

“…18−23 In addition, with the rapid development of wireless communication and the huge amount of information discovery since the start of the 21 st century, there are new and higher requirements for microwave dielectric ceramics. 5,8,11 The focus of academic attention has shifted more and more toward investigating the upper limit of dielectric properties and looking for new low-loss candidates to meet emerging requirements. Based on this, we previously systematically investigated the synthesis of Sr ties (ε r = 63, Q × f = 84,000 GHz, and τ f = 293 ppm/°C).…”

Combined experimental and DFT study on high‐temperature thermochromism of Co‐doped LaCrO3 coating for thermal indicator

“…For example, the LaCrO 3based materials are used in a variety of colors of paints and photothermal coatings, which is ascribed to lattice distortion caused by doping and octahedrally coordinated 3d (Cr)−2p (O) charge-transfer transitions. [33][34][35] Moreover, elemental doping affects the electronic structure and introduces impurity energy levels, which enhances polarization between ions at high temperatures and promotes chargetransfer reactions. 36,37 Meanwhile, the change in temperature and the coordination field of the chromophores can cause changes in the electronic structure and bandgap width, leading to changes in color.…”

“…For perovskite structures, the unique optical properties of Cr 3+ in the Cr–O octahedral also promote its application in optical crystals and optical materials. For example, the LaCrO 3 ‐based materials are used in a variety of colors of paints and photothermal coatings, which is ascribed to lattice distortion caused by doping and octahedrally coordinated 3d (Cr)−2p (O) charge‐transfer transitions 33–35 . Moreover, elemental doping affects the electronic structure and introduces impurity energy levels, which enhances polarization between ions at high temperatures and promotes charge‐transfer reactions 36,37 .…”