"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


Wednesday, July 23, 2014Posted by Jeff Christians

Is Graphene Stable for Photocatalysis?

Read the latest paper from the Kamat Lab!

Is Graphene a Stable Platform for Photocatalysis? Mineralization of Reduced Graphene Oxide with UV-Irradiated TiO2 Nanoparticles

Is Graphene Stable for Photocatalysis

Abstract: The recent thrust in utilizing reduced graphene oxide (RGO) as a support for nanostructured catalyst particles has led to the claims of improved efficiency in solar cells, fuel cells, and photocatalytic degradation of pollutants. Specifically, the robust TiO2 system is often coupled with RGO to improve charge separation and facilitate redox reactions. Here we probe the stability of RGO in the presence of UV-excited TiO2 in aqueous media and establish its reactivity towards OH radicals, a primary oxidant generated at the TiO2 surface. By probing changes in absorption, morphology and total organic carbon content (TOC) we conclusively demonstrate the vulnerability of RGO towards OH attack and raise the concern of its use in many applications where OH are likely to be formed. On the other hand, the OH radical-mediated mineralization could also enable new approaches in tackling environmental remediation of nanocarbons such as RGO, carbon nanotubes, and fullerenes.

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Wednesday, July 23, 2014Posted by Jeff Christians

Size Dependent Excited State of Au Clusters

Read the latest paper from the Kamat Lab!

Size Dependent Excited State Behavior of Glutathione Capped Gold Clusters and Their Light Harvesting Capacity

Size Dependent Excited State of Au Clusters

Abstract: Glutathione protected gold clusters exhibit size dependent excited state and electron transfer properties. Larger size clusters (e.g., Au25GSH18) with core-metal atoms display rapid (<1 ps) as well as slower relaxation (~200 ns) while homoleptic clusters (e.g., Au10-12GSH10-12) exhibit only slower relaxation. These decay components have been identified as metal-metal transition and ligand-to-metal charge transfer respectively. The short lifetime relaxation component becomes less dominant as the size of the gold cluster decreases. The long-lived excited state and ability to participate in electron transfer are integral for these clusters to serve as light harvesting antennae. A strong correlation between the ligand-to-metal charge-transfer excited state lifetime and photocatalytic activity was evidenced from the electron transfer to methyl viologen. The photoactivity of these metal clusters show increasing photocatalytic reduction yield (0.05 - 0.14) with decreasing cluster size, Au25 < Au18 < Au15 < Au10-12. Gold clusters, Au18GSH14, were found to have the highest potential as a photosensitizer based on the quantum yield of electron transfer and good visible light absorption properties.

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Wednesday, July 23, 2014Posted by Jeff Christians

Förster versus Dexter

Read the latest paper from the Kamat Lab!

Size Dependent Energy Transfer Pathways in CdSe Quantum Dot-Squaraine Light Harvesting Assemblies: Förster versus Dexter

Förster versus Dexter

Abstract: Energy transfer coupled with electron transfer is a convenient approach to mimic photosynthesis in light energy conversion. Better understanding of mechanistic details of energy transfer processes is important to enhance the performance of dye or quantum dot sensitized solar cells. Energy transfer through both long range dipole based Förster Resonance Energy Transfer (FRET), and short range Dexter Energy Transfer (DET) mechanisms have been identified to occur between CdSe quantum dots (QDs) linked to a red-infrared absorbing squaraine dye through a short thiol functional group (SQSH). Solutions of SQSH linked to CdSe were investigated through steady-state and time resolved spectroscopy experiments to explore both mechanisms. Photoluminescence studies revealed that smaller QDs had higher energy transfer efficiencies than predicted by FRET, and femtosecond transient absorption experiments revealed faster energy transfer rates in smaller donor QD sizes. These findings supported A DET process dominating at small donor sizes. The presence of both processes illustrates multiple strategies for utilizing energy transfer in light harvesting assemblies and the required considerations in device design to maximize energy transfer gains through either mechanism.

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Thursday, July 17, 2014Posted by Jeff Christians

Why Did You Accept My Paper?

This editorial written by the J. Phys. Chem. Lett. editors appears in today's issue. It highlights manuscript attributes contributing to favorable editorial decisions.

Why Did You Accept My Paper?

This is one question that we never hear from our authors. Authors whose papers get accepted by the editor cherish their publication success, whereas authors whose papers were not accepted may in many instances put the blame squarely on the review process itself. From the author's perspective, the paper he/she just submitted consists of the best scientific results from his/her laboratory and hence deserves publication regardless of the quality of presentation. Editors and reviewers evaluate the papers from the journal reader's viewpoint. Essential factors in drawing a reader's attention to a particular paper include a broad perspective, a good fit with the journal scope, and clear presentation of new scientific findings. Editors and reviewers also check to see whether the paper meets the journal's submission criteria. Those authors who take these aspects into consideration while composing their manuscripts see a significantly higher success rate of acceptance.

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Wednesday, July 10, 2014Posted by Jeff Christians

They Said it Couldn't be Done

Rad Lab Lab Rats Softball Team

Sometimes softball can be a metaphor for life. You can't let the fact that half your team doesn't know the difference between left field and right field stop you, you just have to get back up and keep swinging.

The doubters were proven wrong, the impossible was accomplished, the Lab Rats won a softball game! Some would point out that it took into our third season to get our first win, but I would point out that we actually had a win two years ago when the other team forfeited, so the thrill of victory is not totally unfamiliar territory. While our offense kept us competitive in our first game, it was our stifling defense that helped us prevail to our first win of the season ever. We held the MBA team to just 1 run in a game that stretched the full 7 innings. The tone was set in the first inning when Doug unleashed 100% power and hit a huge home run that scored two and put us up for good. The only hiccup was when Jay thought he could be like Doug and ended up getting out after being thrown into a pickle between third and home. Nevertheless, the final score of 6-1 smelled of glory and tasted of victory! If we win our next game we make the playoffs!

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