Coupling of Single Quantum Dots to Smooth Metal Films

Jul 20, 2009

Scientists at Argonne National Laboratory's CNM Nanophotonics Group have measured how light emission from individual colloidal semiconductor nanocrystals, or quantum dots, is modified when in proximity to smooth metal films.

Metal can strongly modify how emit light because of their coupling to electron oscillations in the metal, known as surface plasmons. Emission modification is important for the improvement of light-emitting devices, development of novel imaging techniques, and observation of novel phenomena, such as nanoscale lasing.

Quantum dots and metal nanoparticles can exhibit significant variation in size and shape, however, which makes it difficult to extract quantitative information. The new study alleviates this problem by employing single quantum dots near a smooth gold film. Even using single dots, measurements are difficult because of the well-known phenomenon of fluorescence , or blinking.

The CNM scientists developed a time-resolved single-photon counting technique to extract intrinsic emission rates, thereby resolving for the first time coupling between individual quantum dots and the metal surface.

Reference: X. Wu, Y. Sun, and M. Pelton, Phys. Chem. Chem. Phys. 11, 5867 (2009).

Provided by

Explore further: Team finds electricity can be generated by dragging saltwater over graphene

add to favorites email to friend print save as pdf

Related Stories

Argonne researcher studies what makes quantum dots blink

Oct 02, 2007

In order to learn more about the origins of quantum dot blinking, researchers from the U.S. Department of Energy's Argonne National Laboratory, the University of Chicago and the California Institute of Technology ...

Scientists Solve Problem of Quantum Dot 'Blinking'

Jan 23, 2008

Quantum dots—tiny, intense, tunable sources of colorful light—are illuminating new opportunities in biomedical research, cryptography and other fields. But these semiconductor nanocrystals also have a ...

Researchers set new record for brightness of quantum dots

Sep 25, 2007

By placing quantum dots on a specially designed photonic crystal, researchers at the University of Illinois have demonstrated enhanced fluorescence intensity by a factor of up to 108. Potential applications include high-brightness ...

Recommended for you

First direct observations of excitons in motion achieved

Apr 16, 2014

A quasiparticle called an exciton—responsible for the transfer of energy within devices such as solar cells, LEDs, and semiconductor circuits—has been understood theoretically for decades. But exciton ...

User comments : 0

More news stories

Thinnest feasible nano-membrane produced

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Turning off depression in the brain

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...

Is Parkinson's an autoimmune disease?

The cause of neuronal death in Parkinson's disease is still unknown, but a new study proposes that neurons may be mistaken for foreign invaders and killed by the person's own immune system, similar to the ...