Boosting Upconversion through Selective Interfacial Energy Transfer toward Infrared Sub-bandgap Photodetection

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Photon upconversion in nanocrystals is promising for applications but hindered by concentration quenching.
• Conventional nanoparticles struggle with high doping levels due to this effect.

Purpose of the Study:

• To introduce a conceptual model for boosting upconversion efficiency in nanocrystals.
• To address the challenge of concentration quenching in heavy doping scenarios.

Main Methods:

• Utilizing core-shell nanocrystals with controlled interfacial energy transfer (IET).
• Achieving 100% doping of sensitizer and activator within a single nanocrystal.
• Atomically manipulating interfacial interactions between Erbium (Er) and Ytterbium (Yb) sublattices.

Main Results:

• A 2-orders-of-magnitude enhancement in luminescence intensity was achieved.
• Nonradiative energy loss was significantly minimized.
• Demonstrated temporal tuning of switchable red-to-green emission colors via IET channels.

Conclusions:

• The proposed model effectively boosts upconversion by controlling IET and minimizing energy loss.
• Provides new insights into upconversion physics in heavily doped nanomaterials.
• Offers potential for advanced infrared photodetection and photonic applications.