Prashant V. Kamat

Bio: Prashant V. Kamat is an academic researcher from University of Notre Dame. The author has contributed to research in topics: Racism & Excited state. The author has an hindex of 140, co-authored 725 publications receiving 79259 citations. Previous affiliations of Prashant V. Kamat include Indian Institute of Technology Kanpur & Council of Scientific and Industrial Research.

Electrochemically assisted photocatalysis: titania particulate film electrodes for photocatalytic degradation of 4-chlorophenol

Abstract: A commercially available TiO[sub 2] powder (Degussa P25) has been used to prepare thin particulate films on conducting glass plates. These semiconductor particulate films are photoelectrochemically active with properties similar to an n-type semiconductor. The recombination between the photogenerated charge carriers can be suppressed by applying an external anodic bias. Electron scavengers, such as oxygen, affect the photocurrent generation by competing for the photogenerated electrons. These particulate films provide a convenient method for accelerating the photocatalytic reaction by applying an external bias. For example, the rate of photocatalytic degradation of 4-chlorophenol greatly increases when the TiO[sub 2] particulate film electrode is maintained at an external anodic bias (0.6 V vs SCE) during the UV photolysis. 26 refs., 6 figs.

Boosting the efficiency of quantum dot sensitized solar cells through modulation of interfacial charge transfer.

Abstract: The demand for clean energy will require the design of nanostructure-based light-harvesting assemblies for the conversion of solar energy into chemical energy (solar fuels) and electrical energy (s...

Cu2S Reduced Graphene Oxide Composite for High-Efficiency Quantum Dot Solar Cells. Overcoming the Redox Limitations of S2–/Sn2– at the Counter Electrode

Abstract: Polysulfide electrolyte that is employed as a redox electrolyte in quantum dot sensitized solar cells provides stability to the cadmium chalcogenide photoanode but introduces significant redox limitations at the counter electrode through undesirable surface reactions. By designing reduced graphene oxide (RGO)-Cu2S composite, we have now succeeded in shuttling electrons through the RGO sheets and polysulfide-active Cu2S more efficiently than Pt electrode, improving the fill factor by ∼75%. The composite material characterized and optimized at different compositions indicates a Cu/RGO mass ratio of 4 provides the best electrochemical performance. A sandwich CdSe quantum dot sensitized solar cell constructed using the optimized RGO-Cu2S composite counter electrode exhibited an unsurpassed power conversion efficiency of 4.4%.

Semiconductor−Metal Nanocomposites. Photoinduced Fusion and Photocatalysis of Gold-Capped TiO2 (TiO2/Gold) Nanoparticles

Abstract: Semiconductor/metal composite nanoparticles have been synthesized by chemically reducing HAuCl4 on the surface of preformed TiO2 nanoparticles. These gold-capped TiO2 nanoparticles (particle diameter 10−40 nm) were stable in acidic (pH 2−4) aqueous solutions. At low [TiO2]:[Au] ratio (<1:1), these composite nanoparticles are bigger in size (20−40 nm) and readily undergo aggregation. The TiO2/Au nanoparticles with TiO2:Au ratio ≥1:10 were relatively stable to 532 nm laser irradiation. On the other hand 532 nm laser pulse excitation of aggregated nanoparticles ([TiO2]:[Au] ≤ 1:1) led to morphological changes as they fused to produce large-size particles. Laser-induced melting/fusion was confirmed from the growth in the particle size as well as the disappearance of the aggregation absorption band. The process of melting and fusion occurred with an apparent rate constant of 1.25 × 109 s-1. The role of the gold layer in promoting the photocatalytic charge transfer has been probed using thiocyanate oxidation at...

Improving the Photoelectrochemical Performance of Nanostructured TiO2 Films by Adsorption of Gold Nanoparticles

Abstract: TiO2 films cast on conducting glass plates were modified by adsorbing gold nanoparticles (5 nm diameter) from a toluene solution. Selective formation of Au islands and larger particles on the TiO2 surface could be seen from transmission electron micrographs and AFM images. Although the adsorbed Au particles are larger in diameter (50−70 nm), they retain surface plasmon characteristics, similar to those observed for smaller gold nanoparticles in solutions. A 3-fold enhancement in photocurrent generation has been achieved upon modification of TiO2 films with Au nanoparticles. This improved photoelectrochemical performance is explained on the basis of improved interfacial charge-transfer kinetics of the TiO2/Au composite film. Such semiconductor−metal composite films have potential applications in improving the performance of photoelectrochemical solar cells.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Organometal Halide Perovskites as Visible-Light Sensitizers for Photovoltaic Cells

Abstract: Two organolead halide perovskite nanocrystals, CH3NH3PbBr3 and CH3NH3PbI3, were found to efficiently sensitize TiO2 for visible-light conversion in photoelectrochemical cells. When self-assembled on mesoporous TiO2 films, the nanocrystalline perovskites exhibit strong band-gap absorptions as semiconductors. The CH3NH3PbI3-based photocell with spectral sensitivity of up to 800 nm yielded a solar energy conversion efficiency of 3.8%. The CH3NH3PbBr3-based cell showed a high photovoltage of 0.96 V with an external quantum conversion efficiency of 65%.

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides

Abstract: To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Films and powders of TiO 2- x N x have revealed an improvement over titanium dioxide (TiO 2 ) under visible light (wavelength 2 has proven to be indispensable for band-gap narrowing and photocatalytic activity, as assessed by first-principles calculations and x-ray photoemission spectroscopy.