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New-phase retention in colloidal core/shell nanocrystals via pressure-modulated phase engineering
Yixuan Wang1, Hao Liu1, Min Wu1
1State Key Laboratory of Superhard Materials, College of Physics, Jilin University Changchun 130012 China yangxinyi@jlu.edu.cn zoubo@jlu.edu.cn.
Chemical Science
|May 27, 2021
Summary
Researchers developed core/shell manganese selenide/manganese sulfide (MnSe/MnS) nanocrystals using a high-pressure method. This process created a novel orthorhombic phase, offering potential for new electronic and magnetic properties.
Area of Science:
- Materials Science
- Nanotechnology
- Solid-State Physics
Background:
- Core/shell nanocrystals (NCs) offer advanced properties due to integrated functionalities.
- Achieving novel crystal phases in NCs, not found in bulk materials, is a significant challenge.
- Crystal structure is crucial for properties like energy conversion and emission in NCs.
Purpose of the Study:
- To develop a novel phase in heterostructured core/shell nanocrystals.
- To investigate the phase transitions of MnSe/MnS core/shell NCs under high pressure.
- To explore the potential for retaining novel phases at ambient conditions.
Main Methods:
- Fabrication of heterostructured core/shell MnSe/MnS NCs using a fast, clean high-pressure approach.
- Analysis of phase transitions using recognizable diffraction patterns under pressure.
- First-principles calculations to determine phase stability.
Main Results:
- Successfully synthesized core/shell MnSe/MnS NCs with a previously undiscovered orthorhombic phase (B31).
- Observed two distinct phase transitions (wurtzite → rocksalt → B31) in the MnSe core, influenced by the MnS shell.
- Determined the B31 phase to be thermodynamically stable under high pressure and potentially retainable at ambient conditions.
Conclusions:
- A novel orthorhombic phase (B31) was created in MnSe/MnS core/shell NCs via high pressure.
- The heterointerface effect plays a key role in regulating core phase transitions.
- The ability to retain this new phase opens avenues for manipulating electronic and magnetic properties.
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