The preparation of luminescent and reversible thermochromic Mn-doped Ca-Zn-Al-O inorganic materials

In this research, we reported the thermochromic and luminescent behaviors of Ca14Zn6Al10-xMnxO35 (x = 0,0.5,1.0,1.5,2) garnet materials prepared by a high-temperature solid-state reaction method. Thermochromism of all samples showed gradual tunability of color with a change in temperature. However, the optimal thermochromic performance was observed for Ca14Zn6Al10-xMnxO35 samples with x = 1 and the sintering temperature of 1200°C. The resultant samples showed a reversible change in color from yellow to reddish yellow when heated to around 500°C. This was due to the changes in absorption bands of Mn4+ and Mn5+ in octahedral and tetrahedral sites, respectively. The materials also exhibited a deep red emission at around 710 nm. The existence of impurity phases was found to degrade the optical properties of the samples.