In situ optical and structural properties of the thermochromic material Nd2MoO6

Abstract

The reversible thermochromic inorganic material of rare earth neodymium molybdate Nd2MoO6 was synthesized by solid state reaction. In the temperature range of 30–300 ℃, the color of the sample changed reversibly from light blue to green. In-situ UV/Vis diffuse reflectance spectroscopy (UV/Vis DRS), in-situ powder X-ray diffraction (XRD) and in-situ Raman spectroscopy were used to study the mechanism of the reversible thermochromism of the materials. In-situ XRD shows that there is no phase transition during heating and cooling. With the increase in temperature, the lattice of the sample expands anisotropically. The lattice extension leads to a change in the ligand field environment around the Nd-O polyhedra, which affects the absorption intensity of the UV/Vis diffuse reflectance spectrum, leading to a change in color. The distorted lattice returns to its initial state after cooling to room temperature.