Related Experiment Video
Updated: Jun 21, 2026
Compact Quantum Dots for Single-molecule Imaging
Published on: October 9, 2012
Optical and magnetic properties of conjugate structures of PbSe quantum dots and gamma-Fe(2)O(3) nanoparticles
Lioz Etgar1, Gregory Leitus, Leonid Fradkin
1Nanoscience and Nanotechnology Program, Technion, Haifa 32000, Israel.
Abstract:
An investigation of the optical and magnetic properties of a unique hydrogen-linked conjugate nanostructure, comprised of superparamagnetic gamma-Fe(2)O(3) nanoparticles (NPs) and near-infrared PbSe nanocrystal quantum dot (NQD) chromophores, is reported. The results show retention of the NQDs' emission quantum efficiency and radiative lifetime, and only a small red shift of its band energy, upon conjugation to the dielectric surroundings of gamma-Fe(2)O(3) NPs. The study also shows the sustainability of the superparamagnetism of the NPs after conjugation, with only a slight decrease of the ferromagnetic-superparamagnetic transition temperature with respect to that of the individual NPs. Thus, the conjugate nanostructure can be considered as a useful medical platform when PbSe NQDs act as fluorescent tags, while the gamma-Fe(2)O(3) NPs are used as a vehicle driven by an external magnetic field for targeted delivery of tags or drugs.
Related Concept Videos
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:42Valence Bond Theory