Large-Area Near-Infrared Emission Enhancement on Single Upconversion Nanoparticles by Metal Nanohole Array

Area of Science:

• Nanotechnology
• Materials Science
• Biophotonics

Background:

• Single lanthanide (Ln) ion doped upconversion nanoparticles (UCNPs) are promising for sensitive biomolecule detection.
• Plasmonic structures can boost UCNP emission efficiency by controlling energy transfer.
• Challenges exist in achieving uniform, large-area modulation of single UCNP emission.

Purpose of the Study:

• To develop a strategy for simultaneous, large-area energy transfer modulation of single UCNPs.
• To enhance the emission efficiency of single UCNPs using plasmonic structures.
• To provide a platform for quantitative single-particle biosensing.

Main Methods:

• Fabrication of metal nanohole arrays (NHAs) for plasmonic coupling.
• Coupling surface plasmon polaritons (SPPs) with specific energy transitions in UCNPs.
• Numerical simulation of electric field distribution and particle location insensitivity.

Main Results:

• Achieved up to 10-fold enhancement in 800 nm emission from single UCNPs.
• Demonstrated enhanced emission by coupling SPPs with higher-intermediate states (¹D₂ transitions).
• Confirmed robustness and location insensitivity of luminescent enhancement via simulations.

Conclusions:

• Metal nanohole arrays offer a viable strategy for large-area, efficient modulation of single UCNP emission.
• The developed method significantly surpasses conventional SPP coupling approaches.
• This platform facilitates broad exploration of single-particle quantitative biosensing.