Related Experiment Video
Updated: May 29, 2026
13:51
Synthesis of Core-shell Lanthanide-doped Upconversion Nanocrystals for Cellular Applications
Published on: November 10, 2017
Copper-doped inverted core/shell nanocrystals with "permanent" optically active holes.
Ranjani Viswanatha1, Sergio Brovelli, Anshu Pandey
1Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
Nano Letters
|September 28, 2011
Summary
We developed novel Cu-doped ZnSe/CdSe colloidal nanocrystals. These materials exhibit unique p-type doping and tunable emission for advanced light-emitting technologies.
Area of Science:
- Materials Science
- Nanotechnology
- Quantum Dots
Background:
- Colloidal nanocrystals offer tunable optoelectronic properties.
- Doping strategies are crucial for controlling charge carrier behavior and emission characteristics.
Purpose of the Study:
- To synthesize and characterize a new class of Cu-doped ZnSe/CdSe colloidal nanocrystals.
- To investigate the doping mechanism and optical properties of these novel nanocrystals.
Main Methods:
- Spectroscopic studies
- Magneto-optical measurements
- Chemical titration with hole-withdrawing molecules
Main Results:
- Conclusive demonstration of Cu impurities as paramagnetic +2 species, acting as a source of optically active holes.
- Identification of a p-type doping signature with the Fermi level in the lower half of the band gap.
- Observation of an electron-only emission mechanism, enhanced by hole-withdrawing molecules and suppressing band-edge emission.
Conclusions:
- The developed Cu-doped ZnSe/CdSe nanocrystals exhibit intrinsic p-type doping and an unusual electron-only emission pathway.
- These materials possess broad emission tunability (1.2–3.1 eV) and large Stokes shifts, reducing reabsorption losses.
- The unique properties make them highly promising for light-emission, lasing technologies, and novel device concepts like "zero-threshold" optical gain.
