Upconversion Luminescence from CdSe Nanoparticles

Journal Article · Wed Jun 08 04:00:00 EDT 2005 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.1930828· OSTI ID:15017409

Chen, Wei; Joly, Alan G; McCready, David E

Efficient upconversion luminescence has been observed from CdSe nanoparticles ranging in size from 2.5 to 6 nm. The upconversion luminescence exhibits a near quadratic laser power dependence. Emissions from both excitons and trap states are observed in the upconversion and photoluminescence spectra, and in the upconversion luminescence the emission from the trap states is enhanced relative to trap state emission in the photoluminescence. The upconversion decay lifetimes are slightly longer than the photoluminescence decay lifetimes. Time-resolved spectral measurements indicate that this is due to the involvement of long decay components from surface or trap states. Both the photoluminescence and upconversion luminescence decrease in intensity with increasing temperature due mainly to thermal quenching. All the observations indicate that surface or trap states work as emitters rather than as intermediate states for upconversion luminescence and that two-photon absorption is the likely excitation mechanism.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15017409
• Report Number(s): PNNL-SA-43873; 2214a; KP1301030
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 22 Vol. 122
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABSORPTION
DECAY
EXCITATION
EXCITONS
LASERS
LUMINESCENCE
PHOTOLUMINESCENCE
QUENCHING
SPECTRA
environmental molecular sciences laboratory