Application of aerodynamic levitation to the formation of glass ceramics

The lighting industry is intensively looking for materials that can generate white light, similar to sunlight. WLED is a new type of semiconductor lighting device, widely used today due to its low cost, long service life, energy efficiency, excellent reliability and environmental friendliness. Commonly used WLED lighting generates light that contains too strong a blue component and no red one, which has a negative impact on health. Our solution is to use Ba₂MgMoO₆ (BMM) as a host for Sm³⁺, as a potential red phosphor to improve the color characteristics of WLEDs.

In this study, the red phosphor of 1% Sm³⁺ ion-doped BMM with a double perovskite structure was prepared using a co-precipitation method. Next, we obtained amorphous structures in the form of balls with a diameter of 1.0 mm, using a unique aerodynamic levitation method. Then, an attempt was made to obtain glass ceramics by crystallising BMM crystallites surrounded by an amorphous structure by heating it at the designated crystallization temperature. The structural and spectroscopic properties of the obtained materials were analyzed.

We can successfully conclude that the obtained BMM:Sm³⁺ materials are good candidates as a red phosphor (CRI=91 and CCT=2943 K), giving a warm white emission. Temperature measurements brought us completely unexpected results. The relative sensitivity calculated from FIR had a maximum of 2.7% K^-1 at -30 ⁰C and another local maximum of 1.6% K^-1 at 75 ⁰C. This value is one of the highest achieved for luminescence thermometry performed only using Sm³⁺ ions. This is an extremely promising precedent for temperature sensing using perovskite materials with high symmetry. Transparent glass samples were obtained (Fig. 1). From the XRD patterns, only a broad diffuse peak is observed, which indicates that the samples are totally amorphous, without any traces of crystalline structure. The SEM images show the homogeneous topography of the sample.