Pressure-induced amorphization of YVO₄:Eu³⁺ nanoboxes

The behavior of nanomaterials under extreme pressure is not fully understood. Prior research has shown that structural changes can occur in crystalline materials when subjected to high pressures. However, the specific transformation mechanisms in doped nanoscale materials remain unclear. Some studies suggest that pressure can induce amorphization in certain compounds. Yet, the local structural similarities between amorphous and crystalline phases under pressure are rarely explored. The role of luminescent dopants like Eu(3+) in tracking such transitions has not been thoroughly examined. This gap motivated the investigation of pressure-induced changes in YVO4:Eu(3+) nanoboxes. The study aimed to clarify how high pressure affects the structural and optical properties of this nanomaterial. Understanding these effects is crucial for applications in high-pressure materials science.

This study aimed to investigate the structural and optical transformations of YVO4:Eu(3+) nanoboxes under high pressure. The researchers focused on the phase transition from a crystalline to an amorphous state. They used x-ray diffraction to identify structural changes above 12.7 GPa. The study also examined the local structure using the pair distribution function. Raman spectroscopy and photoluminescence were employed to confirm the transition. The goal was to determine the pressure thresholds for the phase change and its irreversibility. The researchers also sought to understand the local environments of Eu(3+) ions in the material. By combining multiple techniques, the study aimed to provide a comprehensive view of the high-pressure behavior of these nanoboxes.

X-ray diffraction was used to observe the structural transformation of YVO4:Eu(3+) nanoboxes at pressures above 12.7 GPa. The pair distribution function was analyzed to assess local structural similarities. Raman spectroscopy was applied to detect the phase transition to a scheelite-type structure. Eu(3+) photoluminescence measurements were conducted to confirm the transition at lower pressures. The researchers monitored the irreversibility of the phase change after reaching a maximum pressure of 20 GPa. The study combined experimental data from three independent techniques. The presence of two photoluminescence peaks was used to infer different local environments for Eu(3+). The methods provided a detailed picture of the structural and optical changes under pressure.

X-ray diffraction showed an amorphous phase forming in YVO4:Eu(3+) nanoboxes above 12.7 GPa. The pair distribution function revealed that the local structure resembled the scheelite-type YVO4. Raman spectroscopy confirmed the phase transition to a scheelite-type structure at 10.1 GPa. Eu(3+) photoluminescence detected the same transition at 9.1 GPa. The phase transition was irreversible after reaching a maximum pressure of 20 GPa. Two (5)D0-->(7)F0 photoluminescence peaks were observed in the low-pressure phase. One peak corresponded to the expected Eu(3+) environment substituting Y(3+). The other peak suggested a disordered environment, possibly at the nanobox surface.

The study shows that YVO4:Eu(3+) nanoboxes undergo a pressure-induced amorphization above 12.7 GPa. The local structure of the amorphous phase is similar to the scheelite-type YVO4. Raman and photoluminescence data support the phase transition to a scheelite-type structure at lower pressures. The irreversibility of the transition was observed after reaching 20 GPa. The presence of two photoluminescence peaks indicates two Eu(3+) environments. One environment is consistent with substitution at Y(3+) sites. The other environment suggests surface-related disorder in the nanoboxes. The findings highlight the complex structural and optical behavior of doped nanomaterials under high pressure.