In-situ optical and structural insight of reversible thermochromic materials of Sm3-xBixFe5O12 (x= 0, 0.1, 0.3, 0.5)

• Published in: Dyes and pigments 2017-10, Vol.145, p.418-426
• Main Authors: Liu, Huanhuan, Yuan, Long, Qi, Hui, Wang, Shan, Du, Yanyan, Zhang, Yimeng, Hou, Changmin, Feng, Shouhua
• Format: Article
• Language: English
• Subjects: Raman spectroscopy; Rare-earth iron garnet; Thermochromism; UV-vis spectroscopy
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2017.06.038

Reversible thermochromic inorganic materials of rare-earth iron garnets Sm3-xBixFe5O12 (x = 0, 0.1, 0.3, 0.5) with different ratio of doped Bi3+ were synthesized via high temperature solid state reaction and their structure and properties were investigated by powder x-ray diffraction (XRD), infrared spectroscopy (IR), Raman, and UV-vis-NIR spectroscopy. Refinement of the as-prepared powders XRD results indicates that the lattice constants decreased with the increasing of the doping amount of Bi3+. Thermochromism for all Sm3-xBixFe5O12 (x = 0, 0.1, 0.3, 0.5) samples showed the change in colour from yellow-green to brown and the substitution of Bi3+ ions also affect the colour of the samples. The initial colour of the samples is related to O2−→Fe3+ ligand-to-metal charge transfer at 2.54 eV and d-d transitions peaking at 1.38 and 2.03 eV. The macroscopic thermochromic is originated from charge transfer at lower energy, whereas the d−d is only very weakly affected. This family of materials could be applied as a thermal indicator pigments for cooking tools and hotplates. [Display omitted] •Reversible thermochromic inorganic materials Sm3-xBixFe5O12 (x = 0, 0.1, 0.3, 0.5) were synthesized.•Thermochromism for all Sm3-xBixFe5O12 (x = 0, 0.1, 0.3, 0.5) samples showed the change in colour from yellow-green to brown.•In-situ optical and structural characterization were performed to show the themochromic mechanism.