Download quantum dots, synthesis and applications.

Workshop June 2012
QUANTUM DOTS, SYNTHESIS AND
APPLICATIONS
JESÚS GAONA
[email protected]
As we can see the in the diagram bellow, the
wavelength of the emitted photons is
proportional to the nanoparticle size. The
more energetic radiation corresponds to the
blue light (smaller NPs.)
Quantum dots are nanoparticles, of a
semiconductor material, which range from 2 to
10 nanometers in diameter. Due to their small
size, quantum dots display unique optical and
electrical properties that are different in
character to those of the corresponding bulk
material. The most important feature of
Quantum dots, is the emission of photons
under excitation, which are visible to the
human eye as light. Moreover, the wavelength
of these photon emissions depends not on the
material from which the quantum dot is made,
but its size. [1]
Quantum dots are used in several fields such
as nanobiomedicine, in which they are
employed in diagnostic imaging, helping to
detect tumors and cellular processes. [2]
Due to this severe size reduction, the
continous
bands
(typical
of
semiconductor materials ) turn into
discrete energy levels. This fact is
known as Quantum effect. Now , the
nanoparticles behave like fluorescent
discrete molecules.
One of the most important applications
of Quantum dots is the solar cell
fabrication.
DSSCs, also known as
Graztel cells . [3]
Due to their unique emitting properties,
quantum dots are also applied in LED
fabrication, security inks, photovoltaic
devices, photocatalysis etc.
We can consider Quantum Dots as a
promising technology in development.
REFERENCES:
[1]: (CdSe)ZnS Core-shell Quantum dots. Synthesis and characterization of a size series of highly luminescent nanocrystallites. B.P. Dabbousi et Al. J.Phys.Chem 1997
[2]: Quantum dots as cellular probes. Alvisatos, AP, Gu WW, Larabell C. Annual Review of Biomedical engineering Vol. / 55-76. 2005
[3]: Células solares de titanio nanoestructurado sensitivizado. Alternativas para la generación Fotovoltaica. Juan Bisquert. Junio 2008.
ACKNOWLEDGEMENTS
Jesús Gaona Marín, NANOMAT master student in the academic year 2011-12, acknowledges financial assistance from the University of Zaragoza in the framework of project A_PIECyT_11_1_445.