Colloidal ReO₃ Nanocrystals: Extra Re d-Electron Instigating a Plasmonic Response.

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Rhenium oxide (ReO₃) exhibits metallic properties, enabling localized surface plasmon resonance (LSPR) in its nanocrystalline form.
• Existing synthesis methods for metal oxide nanocrystals often involve complex ligand exchange procedures for solvent compatibility.

Purpose of the Study:

• To develop a novel colloidal synthesis route for ReO₃ nanocrystals (NCs).
• To investigate the plasmonic properties and optical modulation capabilities of these ReO₃ NCs.

Main Methods:

• Colloidal synthesis of ReO₃ NCs via a hot-injection route, reducing Re(+7) oxide with a long-chain ether.
• Characterization using Mie theory simulations and Drude modeling to analyze optical properties.
• Electrochemical charging via ion (de)insertion to induce dynamic optical modulation.

Main Results:

• Successful synthesis of ReO₃ NCs with ether and hydroxyl surface ligands, allowing easy solvent switching.
• Observation of LSPR bands around 590 nm and interband absorptions at 410 nm.
• Demonstration of reversible dynamic optical modulation of ReO₃ NC films via electrochemical ion insertion/deinsertion.

Conclusions:

• The novel synthesis protocol yields ReO₃ NCs with tunable plasmonic properties.
• Electrochemical ion insertion enables dynamic optical modulation of ReO₃ NC films, a phenomenon not observed in bulk ReO₃.
• This work facilitates further exploration of plasmonic applications for ReO₃ nanocrystals.