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08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
9.0K
Bimetallic Ions Codoped Nanocrystals: Doping Mechanism, Defect Formation, and Associated Structural Transition
Qingbo Sun, Changlin Zheng, Larissa Q Huston
1School of Physical, Environmental and Mathematical Sciences, University of New South Wales , Australian Capital Territory, Canberra 2601, Australia.
The Journal of Physical Chemistry Letters
|June 30, 2017
Summary
Ionic codoping effectively incorporates difficult dopants like Indium (In3+) into titanium dioxide (TiO2) nanocrystals. This study reveals defect structures that influence high-pressure phase transitions, enabling rational material design.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Chemistry
Background:
- Ionic codoping is key for tuning material properties.
- Incorporating difficult-to-dope ions at high concentrations via wet chemistry remains challenging.
- Understanding codopant incorporation and defect structures is crucial for rational material design.
Purpose of the Study:
- Investigate the doping mechanisms of In3+ (difficult-dopant) and Nb5+ (easy-dopant) in anatase TiO2 nanocrystals.
- Characterize the defect structures formed by codoping.
- Analyze the impact of these defects on high-pressure induced structural transitions.
Main Methods:
- Experimental synthesis of In3+ and Nb5+ codoped TiO2 nanocrystals.
- Theoretical modeling to understand defect formation and structures.
- High-pressure experiments to observe structural transition behaviors.
Main Results:
- Dual mechanisms (nucleation and diffusion) enable synergistic incorporation of In3+ and Nb5+.
- Defect structures comprise clusters and pairs of In3+, Nb5+, Ti3+, and oxygen vacancies.
- These defects act as nucleation sites for metastable phases, inducing abnormal structural transitions under pressure.
Conclusions:
- Presents an effective strategy for synthesizing codoped nanocrystals with high concentrations of difficult dopants.
- Highlights the critical role of local defect structures in dictating material properties and phase transitions.
- Advances the fundamental understanding of codoping mechanisms in nanomaterials.
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