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Nanostructure of Er3+ doped silicates.
Nan Yao1, Kirk Hou, Christopher D Haines
1Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ 08544, USA. nyao@princeton.edu
Journal of Electron Microscopy
|August 27, 2005
Summary
Annealing amorphous silicate nanopowders doped with Er3+ ions induces nanostructural changes. These structural modifications significantly enhance photoluminescence properties in the resulting nanocrystalline materials.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Chemistry
Background:
- Amorphous silicates doped with rare-earth ions are promising for optical applications.
- Controlling nanostructure is key to optimizing photoluminescence (PL) properties.
Purpose of the Study:
- To investigate the nanostructural evolution of Er3+-doped silicates upon thermal annealing.
- To correlate structural changes with photoluminescence enhancement.
Main Methods:
- Synthesis of amorphous SiO2/Al2O3/Er2O3 (SAE) and SiO2/Y2O3/Er2O3 (SYE) nanopowders.
- Thermal annealing treatments at various temperatures.
- Characterization using High-Resolution Transmission Electron Microscopy (HRTEM), Nano-Energy Dispersed X-ray (NEDX) spectroscopy, X-ray Diffraction (XRD), and photoluminescence analysis.
Main Results:
- Formation of nanocrystallites (approx. 8 nm diameter) observed in SAE at 1000°C and SYE at 1200°C.
- Increased nanocrystalline phase volume fraction with annealing, leading to complete devitrification at 1400°C.
- Identification of a pyrochlore structure (Er(x)Al(2-x)Si2O7 or Er(x)Y(2-x)Si2O7) within a silica matrix.
Conclusions:
- Thermal annealing drives nanostructural evolution in Er3+-doped silicates.
- Nanocrystallization and phase formation are directly linked to significantly enhanced photoluminescence.
- The pyrochlore phase is crucial for the observed optical property improvements.