研究目的
Investigating the photo- and cathodoluminescence of high-temperature optical ceramics synthesized from MgF2 activated with tungsten oxide, to explore their emissive and exploitation characteristics for potential applications in scintillators and luminophores.
研究成果
The synthesized MgF2-based ceramics exhibit intensive luminescence bands at 500 nm and, after annealing, an additional band at 720 nm. The luminescence at 500 nm has spectral-kinetic characteristics similar to known oxygen-containing luminophores like LiF-WO3, ZnWO4, and MgWO4, suggesting the formation of similar luminescence centers, possibly oxygen-vacancy complexes. Annealing introduces new luminescence centers associated with surface oxide phases. These ceramics show promise for applications in scintillators and luminophores due to their high emissive properties and operational advantages over single crystals.
研究不足
The SEM-EDS analysis only probes the subsurface region (about 10 nm deep), which may not represent the bulk composition accurately. The synthesis method using high-energy electron flux is complex and may not be easily reproducible. The luminescence mechanisms are inferred based on similarities to known materials, and further studies are needed to confirm the exact nature of luminescence centers.
1：Experimental Design and Method Selection:
The study involved synthesizing MgF2-based ceramics using a high-energy electron flux from an ELV-6 accelerator as a heater, with WO3 as an activator and LiOH as a coactivator. Luminescence properties were investigated through cathodoluminescence (CL) and photoluminescence (PL) measurements at 300 K.
2：Sample Selection and Data Sources:
Ceramic samples were synthesized from a charge of MgF2 powder with varying ratios of WO3 (0.5-3%) and LiOH (0-3%) additives. Samples were analyzed before and after annealing at 1000°C in air for 7 hours.
3：5-3%) and LiOH (0-3%) additives. Samples were analyzed before and after annealing at 1000°C in air for 7 hours.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Equipment included an ELV-6 accelerator (for synthesis), Quanta 3d 200i SEM with Bruker XFlash MIN SVE EDS system (for surface and elemental analysis), AwaSpec-3648 and AwaSpec-2048 spectrometers (for CL spectra), Agilent Cary Eclipse spectrofluorimeter (for PL spectra and excitation spectra), and a NABERTHERM furnace (for annealing). Materials included MgF2 powder, WO3, and LiOH.
4：Experimental Procedures and Operational Workflow:
The charge was placed in a copper crucible and irradiated with an electron flux (1.4 MeV, 18 kW/cm2 power density) for 1 second to melt and form ceramics. Samples were characterized using SEM and EDS for surface and composition, and luminescence was measured with CL (excited by 250 keV electrons) and PL (excited in 200-350 nm range).
5：4 MeV, 18 kW/cm2 power density) for 1 second to melt and form ceramics. Samples were characterized using SEM and EDS for surface and composition, and luminescence was measured with CL (excited by 250 keV electrons) and PL (excited in 200-350 nm range).
Data Analysis Methods:
5. Data Analysis Methods: Luminescence spectra were normalized and analyzed for band positions, intensities, and decay kinetics using exponential fitting for decay curves. Elemental composition was quantified from EDS data.
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