"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


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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Friday, December 26, 2014Posted by Jeff Christians

Predicting ket at the CdSe-Linker-TiO2 Interface

Read the latest paper from the Kamat Lab!

Predicting the Rate Constant of Electron Tunneling Reactions at the CdSe-Linker-TiO2 Interface

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

Abstract: Current interest in quantum dot solar cells (QDSCs) motivates an understanding of the electron transfer dynamics at the quantum dot (QD) – metal oxide (MO) interface. Employing transient absorption spectroscopy, we have monitored the electron transfer rate (ket) at this interface as a function of the bridge molecules that link QDs to TiO2. Using mercaptoacetic acid (MAA), 3-mercaptopropionic acid (3-MPA), 8-mercaptooctanoic acid (8-MOA) and 16-mercaptohexadecanoic acid (16-MHA) we observe an exponential attenuation of ket with increasing linker length, which has been attributed to the tunneling of the electron through the insulating linker molecule. We model the electron transfer reaction using both rectangular and trapezoidal barrier models that have been discussed in the literature. The one electron reduction potential (equivalent to the lowest unoccupied molecular orbital or LUMO) of each molecule as determined by cyclic voltammetry (CV) was used to estimate the effective barrier height presented by MAA, 3-MPA, 8-MOA and16-MHA at the CdSe-TiO2 interface. The electron transfer rate (ket) calculated for each CdSe-TiO2 interface using both models showed the results in agreement with the experimentally determined trend. This demonstrates that electron transfer between CdSe and TiO2 can be viewed as electron tunneling through a layer of organic linking molecules and provides a useful method for predicting electron transfer rate constants.

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Friday, December 26, 2014Posted by Jeff Christians

Boosting VOC using Gold Clusters

Read the latest paper from the Kamat Lab!

Boosting the Photovoltage of Dye-Sensitized Solar Cells with Thiolated Gold Nanoclusters

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

Abstract: Glutathione-capped gold nanoclusters (Aux-GSH NCs) are anchored along with a sensitizing squaraine dye on a TiO2 surface to evaluate the cosensitizing role of Aux-GSH NCs in dye-sensitized solar cells (DSSCs). Photoelectrochemical measurements show an increase in the photoconversion efficiency of DSSCs when both sensitizers are present. The observed photoelectrochemical improvements in cosensitized DSSCs are more than additive effects as evident from the increase in photovoltage (ΔV as high as 0.24 V) when Aux-GSH NCs are present. Electron equilibration and accumulation within gold nanoclusters increase the quasi-Fermi level of TiO2 closer to the conduction band and thus decrease the photovoltage penalty. A similar beneficial role of gold nanoclusters toward boosting the Voc and enhancing the efficiency of Ru(II) polypyridyl complex-sensitized solar cells is also discussed.

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