Broadband near-infrared luminescence properties of Sc₂(MoO₄)₃:Cr³⁺ molybdates

The structural and spectroscopic properties of Sc₂(MoO₄)₃ molybdate containing various concentrations of Cr³⁺ ions were investigated in a temperature range of 80-300 K. The samples were prepared using hydrothermal as well as solid-state reaction methods. The influence of synthesis conditions and the molybdenum source on the structural properties was studied by X-ray diffraction (XRD), IR (infrared), and Raman methods. The optical properties of Sc₂(MoO₄)₃ samples doped with 0.1, 0.5, 1.0, and 2.0 % of Cr³⁺ ions were investigated. The broadband near-infrared (NIR) luminescence spectra generated from the ⁴T₂ and ²E levels of Cr³⁺ ions may be attractive for NIR light-emitting diode (LED) applications. Emission decay profiles and the crystal field parameters of Cr³⁺ ions are discussed. In particular, the mechanism of photoluminescence generation and the thermal quenching path are described in detail.