Polarized Upconversion of sub-100 nm Single Nanoparticles
Yangjian Cai1,2, Yunfei Shang1, Ming Lu1
1Institute for Biomedical Materials & Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, New South Wales 2007, Australia.
Nano Letters
|August 21, 2024
Summary
Researchers observed polarized upconversion emissions from single nanoparticles below 100 nm. Different nanostructure shapes showed unique polarization, linked to crystallographic orientation and lanthanide ion emission.
Area of Science:
- Materials Science
- Nanotechnology
- Photonics
Background:
- Upconversion nanoparticles (UCNPs) are valuable imaging probes due to photostability and tunable emission.
- Upconversion polarization in UCNPs is under-explored, with prior studies limited to microstructures.
Purpose of the Study:
- To investigate polarized upconversion emissions from single UCNPs at the sub-100 nm scale.
- To understand the factors influencing polarization in different UCNP morphologies.
Main Methods:
- Synthesis of β-NaYF4 single nanostructures (nanorods, nanodiscs, nanoplates) below 100 nm.
- Characterization of upconversion emission polarization degrees.
- Correlation of polarization with crystallographic orientation and spectral profiles of Er3+ transitions.
Main Results:
- Distinct polarized upconversion emissions were observed from individual nanorods, nanodiscs, and nanoplates.
- Polarization degrees varied significantly between morphologies, independent of lanthanide doping concentration.
- Crystallographic orientation relative to the light field was identified as the primary factor controlling polarization.
Conclusions:
- The study reveals controllable polarization in UCNPs at the nanoscale.
- Findings enhance understanding of UCNP optical properties and their dependence on morphology and orientation.
- This work opens avenues for polarization-sensitive UCNP applications in imaging and sensing.
