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.

An Er3+ doped Ba2MgWO6 double perovskite: a phosphor for low-temperature thermometry.

A bifunctional luminescent material is one of the most intriguing topics in recent years with significant growth in the number of investigations. Herein, we report the potential of Ba2MgWO6 doped with Er3+ as a candidate for white-light emitting phosphor and noncontact luminescent thermometry. The synthesis of the samples was carried out by the co-precipitation method. The influence of the dopant concentration on the emission intensity, as well as the capability of temperature readout, was investigated for the first time. The highest emission intensity exhibits a sample comprising 4% Er3+; above it, the concentration quenching process by the dipole-dipole interaction occurs. However, high quality white light generates Ba2MgWO6 with 0.5% of Er3+ due to the coexistence of the host and erbium ion emission with a CIE of (0.30, 0.35). To construct a non-contact luminescent thermometer based on Er3+, the ratio of the emission from 4I11/2 → 4I15/2 to the host emission was examined. The highest sensitivity Sr of the obtained luminescent thermometers was 2.78% K-1 at 198 K. The repeatability of the calculated results and the uncertainty δT of the temperature readout were investigated.