Urea Glass Route as a Way to Optimize YAGG:Ce³⁺,Cr³⁺,Pr³⁺ Nanocrystals for Persistent Luminescence Applications

Abstract

A new approach for the synthesis of Y 3 Al 2 Ga 3 O 12 (YAGG) nanophosphors allowing the preparation of crystallites with sizes starting from 45 nm is presented. The controllability of the energy and trap density of the resulting material samples by annealing temperature was confirmed by thermoluminescence (TL) measurements. It has been shown that the annealing of samples at temperatures up to 1300 °C does not cause any substantial growth of crystallites, still remaining below 100 nm, but leads to changes in the activation energy of the persistent luminescence (PersL) process. On the other hand, annealing above 1400 °C results in grain growth on the submicron scale, which was confirmed by X-ray powder diffraction (XRPD) and electron transmission microscopy (TEM) measurements. In addition, with an increase in the molar ratio of urea to the total amount of metals used ( R ), qualitative changes are observed in the PersL process occurring from the excited states of Cr 3+ and Pr 3+ ions. This proves the influence of the synthesis process, in particular of the metal complexation at its initial stage, on the final structure ordering in the annealed materials. These observations are linked to previously reported defects in the YAGG structure, leading to PersL.

Synergy between structural rigidity and cluster defects in a bright near-infrared Cr3+-based phosphor for excellent thermal stability and long afterglow

“…The Cr 3+ ion can occupy the Al 3+ /Ga 3+ octahedral sites as the ionic radii of Cr 3+ ions (0.615 Å) are comparable with ionic radii of Al 3+ (0.535 Å) and Ga 3+ (0.62 Å) ions. 37 Fig. 1(c) shows the FTIR spectra of Cr 3+ doped YAGG samples and no significant changes in the vibrational frequencies were observed upon incorporation of Cr 3+ ions.…”

“…The Cr 3+ ion can occupy the Al 3+ /Ga 3+ octahedral sites as the ionic radii of Cr 3+ ions (0.615 Å) are comparable with ionic radii of Al 3+ (0.535 Å) and Ga 3+ (0.62 Å) ions. 37…”

Synthesis of cerium-doped gadolinium gallium aluminum garnet (GGAG:Ce) scintillating powder via solvothermal method

“…While solid-state methods are advantageous for certain systems, solution-based methods are preferred for better control over material properties, improved homogeneity, and enhanced scalability in large-scale GGAG: Ce scintillator production. Various solution-based methods, such as the Pechini sol-gel method [7], sol-gel method [8,9], co-precipitation method [10,11], combustion method [8], urea glass method [12], have been explored for GGAG: Ce nanoparticle synthesis. Coprecipitation involves dissolving metal salts in a solution, adding a precipitating agent to form a solid precipitate, and processing it into GGAG: Ce scintillator powder.…”

“…These properties are critical for efficient light collection and detection. The synthesis conditions can affect the wavelength of emitted light, which in turn affects the choice of photodetectors used to capture the scintillation signals [7,[12][13][14][15]. The synthesis process can influence the mechanical integrity and stability of the scintillator material.…”