High Pressure Luminescence and Raman Studies on the Phase Transition of Gd₂O₃:Eu³⁺ Nanorods

Abstract

The cubic Gd2O3:Eu3+ nanorods were synthesized by a hydrothermal method. The SEM image indicated the nanorods with diameter of 30-35 nm and length of 200-500 nm. The structural stability of Gd2O3:Eu3+ nanorods was investigated by in situ high pressure luminescence and Raman spectra up to 18.9 GPa at room temperature. The results reveals a pressure-induced phase transition from cubic to hexagonal structure at about 11.3 GPa. After releasing pressure, the part of hexagonal structure is retained and the other transfers to monoclinic phase.

High-Pressure Phase Transition of Micro- and Nanoscale HoVO4 and High-Pressure Phase Diagram of REVO4 with RE Ionic Radius

“…The intensity of these new Raman peaks increased gradually with increasing pressure, whereas the characteristic peaks of the zircon-type HoVO 4 became more and more indistinct. These variations shown on the Raman pattern of HoVO 4 microcrystals confirmed a pressure-induced structure transformation from zircon-type to scheelite-type, which was similar to the phenomenon observed in YVO 4, 28 ScVO 4, 18 GdVO 4 , 29 and LuVO 4 . 30 In the unit cell of the scheelite structure of HoVO 4 , including four formula units, the V atoms occupy S4 sites of the VO 4 group.…”

Novel Gd(OH)3, GdOOH and Gd2O3 Nanorods: Microwave-Assisted Hydrothermal Synthesis and Optical Properties

“…This behavior is explained by the dehydration process during the phase change, as well as the synthesis method employed, which facilitates the preparation of materials with small particle sizes. Figure 2 shows the representations of the unit cells for the hexagonal Gd(OH) 3 structure with a P63/m space group, the monoclinic GdOOH structure with a P121/m1 space group, and the cubic Gd 2 O 3 structure with an Ia-3 space group [18][19][20] . VESTA program was used for the construction and visualization of these three models 21 .…”

Interpretation of europium(III) spectra

“…The study of the influence of pressure on the luminescence of europium-doped nanoparticles is a popular research topic [680][681][682][683][684][685][686]. Pressure changes have also an influence on the positions of the energy levels of the 4f 6 electronic configuration of Eu 3+ and on the position of the charge-transfer band [687][688][689][690][691][692][693][694][695][696].…”