"Welcome to The Prashant Kamat lab at the University of Notre Dame! With the help of internal and external collaborations we have established a successful multidisciplinary research program in nanostructure architectures and energy conversion processes." - Prashant Kamat

Kamat Lab News

Thursday, May 7, 2015Posted by Sebastian Snowberger

Synergistic Effects in the Coupling of Plasmon Resonance of Metal Nanoparticles with Excited Gold Clusters

Read the latest paper from the Kamat Lab!

Synergistic Effects in the Coupling of Plasmon Resonance of Metal Nanoparticles with Excited Gold Clusters

Synergistic Effects in the Coupling of Plasmon Resonance of Metal Nanoparticles with Excited Gold Clusters

Abstract: When molecules or clusters are within the proximity of metal particles, their electronic transitions can be drastically enhanced. We have now probed the off-resonance excitation of molecule-like, glutathione-capped gold clusters (Au-GSH) in the close proximity of larger (plasmonic) Au and Ag nanoparticles. The excited state absorption spectrum of Au-GSH* is obtained with monophotonic excitation. The characteristic absorption of Au-GSH* allows us to probe the influence of excited plasmonic nanoparticles coupled with the clusters. Although infrared (775 nm) lasers pulses do not produce Au-GSH*, the excited states of these clusters are formed when coupled with metal (Au, Ag) nanoparticles. Interestingly, the coupled excitation of Au-GSH/AgNP with 775 nm laser pulses also results in an enhanced field effect, as seen from increased plasmon response of the metal nanoparticles. Transient absorption measurements confirm the synergy between these two inherently different nanomaterials, causing them to display greater excitation features. Better understanding of metal cluster–metal nanoparticle interactions will have important implications in designing light harvesting systems, and optoelectronic devices.

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Thursday, April 23, 2015Posted by Sebastian Snowberger

Congratulations to Dr. Jeffrey Christians and Dr. Douglas Hines!

Congratulations to Dr. Jeffrey Christians and Dr. Douglas Hines!

Congratulations to graduate students Jeffrey Christians and Douglas Hines, who completed their Ph.D.s in Chemical and Biomolecular Engineering and Chemistry, respectively!

Jeff successfully defended his thesis entitled:

Mesostructured Thin Film Solar Cells: Examining Hole Transfer Mechanisms and Device Stability,

and was awarded the Eli J. and Helen Shaheen Graduate School Award in the Division of Engineering.

Doug successfully defended his thesis entitled:

Excited State Reactions at the Quantum Dot Surface,

and was awarded the Eli J. and Helen Shaeen Graduate School Award in the Division of Science.

Congratulations for completion of your Ph.D.s and having your excellent work recognized by the Graduate School!

Friday, February 27, 2015Posted by Sebastian Snowberger

Jeff Christians - National Renewable Energy Laboratory Postdoc

Graduate Student Jeff Christians gets postdoc at NREL

Join us in congratulating graduate student Jeffrey Christians who will be joining the National Renewable Energy Laboratory in Golden, CO (a suburb of Denver) as a postdoc with Dr. Joseph Luther! Jeff will be starting at NREL in May and will be working with Dr. Luther and others there to further develop and understand perovskite solar cells.

Friday, January 30, 2014Posted by Sebastian Snowberger

Humidity Effects on CH3NH3PbI3

Read the latest paper from the Kamat Lab!

Transformation of the Excited State and Photovoltaic Efficiency of CH3NH3PbI3 Perovskite upon Controlled Exposure to Humidified Air

Humidity Effects on CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>

Abstract: Humidity has been an important factor, in both negative and positive ways, in the development of perovskite solar cells, and will prove critical in the push to commercialize this exciting new photovoltaic technology. The interaction between CH3NH3PbI3 and H2O vapor is investigated by characterizing the ground state and excited state optical absorption properties, and probing morphology and crystal structure. These systematic undertakings elucidate the complex interaction inherent in this system, demonstrating that H2O exposure does not simply only CH3NH3PbI3 to revert to PbI2. It is shown that, in the dark, H2O is able to complex with the perovskite, forming a hydrate product similar to (CH3NH3)4PbI6•2H2O. This causes a decrease in absorption across the visible region of the spectrum and a distinct change in the crystal structure of the material. Femtosecond transient absorption spectroscopic measurements show the effect that humidity has on the ultrafast excited state dynamics of CH3NH3PbI3. More importantly, the deleterious effects of humidity on complete solar cells, specifically on photovoltaic efficiency and stability, are explored in light of these spectroscopic understandings.

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Saturday, December 27, 2014Posted by Jeff Christians

Water Splitting with CH3NH3PbI3/BiVO4

Read the latest paper from the Kamat Lab!

All Solution-Processed Lead Halide Perovskite-BiVO4 Tandem Assembly for Photolytic Solar Fuels Production

Size-Dependent Photovoltaic Performance of CuInS2 Quantum Dots Sensitized Solar Cells

Abstract: The quest for economic, large scale hydrogen production has motivated the search for new materials and device designs capable of splitting water using only energy from the sun. Here we introduce an all solution-processed tandem water splitting assembly composed of a BiVO4 photoanode and a single-junction CH3NH3PbI3 hybrid perovskite solar cell. This unique configuration allows efficient solar photon management, with the metal oxide photoanode selectively harvesting high energy visible photons and the underlying perovskite solar cell capturing lower energy visible-near IR wavelengths in a single-pass excitation. Operating without external bias under standard AM 1.5G illumination, the photoanode-photovoltaic architecture, in conjunction with an earth-abundant cobalt phosphate catalyst, exhibits a solar-to-hydrogen conversion efficiency of 2.5% at neutral pH. The design of low-cost tandem water splitting assemblies employing single-junction hybrid perovskite materials establishes a potentially promising new frontier for solar water splitting research.

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Friday, December 26, 2014Posted by Jeff Christians

Chemistry of Materials - Cover Article

Chemistry of Materials - Cover ArticleCongratulations to graduate student Danilo Jara on the cover art for the journal Chemistry of Materials! The cover art appeared in this month's issue of Chemistry of Materials to go along with Danilo, Joon, Kevin, and Prashant's article on the size effect of CuInS2 entitled, Size-Dependent Photovoltaic Performance of CuInS2 Quantum Dots Sensitized Solar Cells.

About the Image: CuInS2 quantum dots with pyramidal shape display size-dependent photovoltaic performance. The origin of the photocurrent was found to arise from defect states, and an optimal size was identified based on charge stabilization.

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