Eu³⁺ doped Ba₂MgWO₆ (BMW) double-perovskite was successfully synthesized for the first time by the co-precipitation method. The synthesis procedure, crystal structure, as well as morphology of obtained samples are presented. Domination of the ⁵D₀–⁷F₁ magnetic–dipole over forced electric–dipole transitions in the emission spectra indicates that Eu³⁺ ions are located in the high symmetry site with inversion center. Only one emission line assigned to the ⁵D₀–⁷F₀ transition was observed, confirming that europium substituted for only one host cation site. The photoluminescence excitation (PLE) spectrum is dominated by a strong and broad band related to the O²⁻ → Eu³⁺ and O²⁻ → W⁶⁺ charge transfer. The decay of the emission from the ⁵D₀ and ⁵D₁ levels was investigated. The temperature-dependent emission spectra showed that the T_0.5 is equal to 350 K. Extinguishing mechanisms of the Eu³⁺ luminescence in the studied host are discussed.

We present double-perovskite molybdate with the formula of Ba₂MgMoO₆ doped with Sm³⁺ ions as a potential red phosphor to improve the color characteristics of white-light-emitting dioded (wLEDs). The new orange–red phosphor was synthesized using the co-precipitation (CP) method, and then its structural and spectroscopic properties were determined. Red emission at 642.6 nm dominates, which results from the electric dipole (ED) transition of the ⁴G_5/2 → ⁶H_9/2 type, and the materials are characterized by short luminescence decay times. BMM:Sm³⁺ is, to our best knowledge, the clearest example of dominant red emission of Sm³⁺ resulting from the location of the dopant in octahedral sites of high-symmetry cubic structure. In the sample containing 0.1% Sm³⁺, Sm³⁺ ions are located in both Mg²⁺ and Ba²⁺ sites, while at higher concentrations the Ba²⁺ site is less preferable for doping, as a result of which the emission becomes more uniform and single-site. The relative sensitivity calculated from FIR has a maximum of 2.7% K⁻¹ at −30 °C and another local maximum of 1.6% K⁻¹ at 75 °C. Such value is, to the best of our knowledge, one of the highest achieved for luminescent thermometry performed using only Sm³⁺ ions. To sum up, the obtained materials are good candidates as red phosphor to improve the color characteristics of wLEDs, obtaining a color-rendering index (CRI) of 91 and coordinated color temperature (CCT) of 2943 K, constituting a warm white emission. In addition to this, a promising precedent for temperature sensing using high-symmetry perovskite materials is the high sensitivity achieved, which results from the high symmetry of the BMM host.

Herein, the structure, morphology, as well as optical properties of the powder and ceramic samples of Ba₂MgWO₆ are presented. Powder samples were obtained by high temperature solid-state reaction, while, for the ceramics, the SPS technique under 50-MPa pressure was applied. The morphology of the investigated samples showed some agglomeration and grains with a submicron size of 490–492 µm. The theoretical density and relative density of ceramics were calculated using the Archimedes method. The influence of sample preparation on the position, shape, and character of the host, as well as dopants emission was investigated. Sample sintering enhances regular emission of WO₆ groups causing a blue shift of Ba₂MgWO₆ emission. Nonetheless, under X-ray excitation, only the green emission of inversion WO₆ group was detected. For the ceramic doped with Eu³⁺ ions, the emission of both host and dopant was detected. However, for the powder efficient host to activator energy, the transfer process occurred, and only the magnetic dipole emission of Eu³⁺ was detected. The intensity of Nd³⁺ ions of Ba₂MgWO₆ powder sample is five times higher than for the ceramic. The sintering process reduces inversion defects and creates a highly symmetrical site of neodymium ions. The emission of Ba₂MgWO₆:Nd³⁺ consists of transitions from the ⁴F_3/2 excited level to the ⁴I_J multiplet states with the dominance of the ⁴F_3/2→⁴I_11/2 one. The spectroscopic quality parameter and branching ratio of Nd³⁺ emission are presented.

In this work, we present a comparative study of LaAlO₃:Pr³⁺ materials in both crystalline and amorphous specimens, exploring how structural differences influence their optical properties.