Assembling semiconductor nanostructures on electrode surfaces in a controlled fashion is an attractive approach for designing next generation solar cells. In recent years, quantum dot solar cells have emerged as the potential contender for making transformative changes. The size dependent electronic structure of quantum dots enables the design of photovoltaic devices with tailored electronic properties. We have now exploited this aspect in solar cells by assembling different size CdSe quantum dots on mesoscopic TiO2 films either by direct adsorption or with the aid of molecular linkers. Upon bandgap excitation, CdSequantum dots inject electrons into TiO2 nanoparticles and nanotubes, thus enabling the generation of photocurrent in a photoelectrochemical solar cell. The charge transfer dynamics between different size CdSe quantum dots and various oxide substrates have been evaluated using transient absorption spectroscopy. The dependence of electron transfer rate constant on the energy gap and its implication in photoconversion efficiency of quantum dot solar cells will be discussed. Ways to improve power conversion efficiency and maximize the light harvesting capability through the manipulation of Cu2S/grapheme oxide counter electrode and carbon nanostructure-semiconductor hybrid assemblies will also be presented.
Prashant V. Kamat is a Rev. John A. Zahm, C.S.C., Professor of Science in the Department ofChemistry and Biochemistry and Radiation Laboratory at University of Notre Dame. He is also a Concurrent Professor in the Department of Chemical and Biomolecular Engineering. 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. Professor Kamat has for nearly three decades worked to build bridges between physical chemistry and material science to develop advanced nanomaterials that promise cleaner and more efficient light energy conversion.
Professor Kamat’s research has made significant contributions to four areas: (1) Photoinduced catalytic processes using semiconductor and metal nanoparticles, nanostructures and nanocomposites, (2) Development of light energy harvesting assemblies (e.g., quantum dots and inorganic-organic hybrid assemblies) for next generation solar cells, (3) Utilization of carbon nanostructures (SWCNT and graphene) as conducting scaffolds to collect and transport charge carriers in solar cells and fuel cells, and (4) Environmental remediation using advanced oxidation processes and chemical sensors.
He has directed DOE funded solar photochemistry research for the past 20 years. In addition to large multidisciplinary interdepartmental and research center programs, he has actively worked with industry-sponsored research. He has served on many national panels on nanotechnology and energy conversion processes. He has published more than 400 scientific papers that have been well received by the scientific community (25000+ citations with a h-index of 90).
In 2010, Kamat was named by the American Chemical Society as the deputy editor of a new publication, the Journal of Physical Chemistry Letters. He is a member of the advisory board of scientific journals, Langmuir, Research on Chemical Intermediates, Applied Electrochemistry and Interface. He was awarded Honda-Fujishima Lectureship award by the Japanese Photochemical Society in 2006 and CRSI medal by the Chemical Research Society of India in 2011. He is a Fellow of the Electrochemical Society, American Chemical Society (ACS) and American Academy of Science (AAAS).