Quantum Dot Solar Cells. Semiconductor Nanocrystals As Light Harvesters
Prashant V. Kamat
Department of Chemistry and Biochemistry, Department of Chemical and Biomolecular Engineering,
University of Notre Dame, Notre Dame, IN 46556
http://www.nd.edu/~pkamat
Renewable energy resources are needed to meet our clean energy demand. The emergence of
semiconductor nanocrystals as the new building blocks of nanotechnology has opened up new
ways to utilize them in next generation solar cells. Recent developments in the utilization of
semiconductor quantum dots for light energy conversion show three major ways to utilize them
in solar cells: (i) Metal-Semiconductor or Schottky junction photovoltaic cell (ii) Polymersemiconductor hybrid solar cell and (iii) Quantum dot sensitized solar cell.[1-3] Of particular
interest is quantum dot solar cell which can be constructed by assembling CdSe quantum dots on
TiO2 films. These composite semiconductor nanostructures can be tailored to tune the
photoelectrochemical response via size control of CdSe quantum dots and improve the
photoconversion efficiency by facilitating the charge transport through TiO2 nanotube
architecture. Ways to improve power conversion efficiency and maximize the light harvesting
capability through the construction of a rainbow solar cell will be presented. The salient features
of carbon nanotube scaffolds[4] for facilitating charge collection and charge transport will also
be discussed.
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Aluminu
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IT
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Semiconductor
Nanocrystals
CdSe
IT
O
PE
D
et
al
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(a)
h
TiO2
h
Glass
Glass
Redox or Hole
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e
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m
Aluminu
e
Active Polymer/
Semiconductor Layer
h
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Pt
OTE
(b)
(c)
Figure 1. Schematic diagram showing the strategies to develop quantum dot (semiconductor
nanocrystal) based solar cells: (a) Metal-semiconductor junction, (b) Polymer-semiconductor
and (c) Semiconductor-Semiconductor systems
References:
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Kamat, P. V., Meeting the Clean Energy Demand: Nanostructure Architectures for Solar Energy
Conversion. J. Phys. Chem. C, 2007, 111, 2834 - 2860.
Kongkanand, A.; Tvrdy, K.; Takechi, K.; Kuno, M. K.;Kamat, P. V., Quantum Dot Solar Cells. Tuning
Photoresponse through Size and Shape Control of CdSe-TiO2 Architecture. J. Am. Chem. Soc., 2008, 130,
4007 - 4015.
Robel, I.; Kuno, M.;Kamat, P. V., Size-Dependent electron Injection from Excited CdSe Quantum Dots into
TiO2 Nanoparticles. J. Am. Chem. Soc., 2007, 129, 4136 -4137.
Kongkanand, A.;Kamat, P. V., Electron Storage in Single Wall Carbon Nanotubes. Fermi Level
Equilibration in Semiconductor–SWCNT Suspensions. ACS Nano, 2007, 1, 13-21.
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Prashant V. Kamat is a Professor of Chemistry & Biochemistry, a Senior Scientist at Radiation Laboratory, and
Concurrent Professor of Department of Chemical and Biomolecular Engineering, University of Notre Dame.
He earned his doctoral degree (1979) in Physical Chemistry from the Bombay University, and postdoctoral research at
Boston University (1979-1981) and University of Texas at Austin (1981-1983). He joined Notre Dame in 1983 and initiated
the project on utilizing semiconductor nanostructures for light energy conversion.
His major research interests are in three areas : (1) catalytic reactions using semiconductor and metal nanoparticles,
nanostructures and nanocomposites, (2) develop advanced materials such as inorganic-organic hybrid assemblies and
functionalized carbon nanotubes for energy conversion, and (3) environmental remediation using advanced oxidation
processes and chemical sensors. He is currently serving as an Executive Editor of Journal of Physical Chemistry
A/B/C and a member of the advisory board of scientific journals, Langmuir, Research on Chemical Intermediates,
Electrochemistry and Solid State Letters, and Interface. He has written more than 350 peer-reviewed journal papers,
review articles and book chapters. He has edited two books in the area of nanoscale materials. He was a fellow of Japan
Society for Promotion of Science during 1997 and 2003 and was awarded Honda-Fujishima Lectureship award by the
Japanese Photochemical Society in 2006. He was elected as a Fellow of the Electrochemical Society in 2008.
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