Author
Prashant V. Kamat
Other affiliations: Indian Institute of Technology Kanpur, Council of Scientific and Industrial Research, Université du Québec à Trois-Rivières ...read more
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.
Topics: Racism, Excited state, Electron transfer, Quantum dot, Flash photolysis
Papers published on a yearly basis
Papers
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TL;DR: In this article, photochemical and photophysical processes that directly influence the photocatalytic properties of semiconductor colloids and the factors that limit the charge transfer at the semiconductor/electrolyte interface are discussed.
128 citations
TL;DR: In this article, the potential of a coupled electrode in bringing about an efficient charge separation in nanocrystalline DSPE cells has been highlighted, and the importance of the proper placement of the energy levels of individual semiconductor components in the coupled system for vectorial el...
Abstract: In an effort to suppress charge recombination in nanoporous dye sensitized photoelectrochemical (DSPE) solar cells, nanocrystalline coupled semiconductor electrodes of the type OTE/SnO2/TiO2 have been prepared, and their photosensitization with a ruthenium polypyridyl complex, Ru(II), has been carried out (OTE is an optically transparent electrode). Improved photoresponse, i.e., higher incident photon to current conversion efficiency (IPCE), higher photovoltage, lower back-electron-transfer rate, kr, and similar front- and back-face action spectra in the coupled OTE/SnO2/TiO2/Ru(II) system compared to those for simple OTE/SnO2/Ru(II) and OTE/TiO2/Ru(II) ones emphasize the potential of a coupled electrode in bringing about an efficient charge separation in nanocrystalline DSPE cells. A negligible photocurrent in a reverse composite OTE/TiO2/SnO2/Ru(II) system underscores the importance of the proper placement of the energy levels of individual semiconductor components in the coupled system for vectorial el...
128 citations
TL;DR: In this paper, a photoinduced morphological changes have been elucidated using picosecond laser flash photolysis, showing that a growth in the particle size (5−20 nm) is observed as a result of melting and fusion of gold nanoparticles, and that adsorption of the cationic dye on the gold surface results in surface charge neutralization causing the Au/dye assembly to aggregate.
Abstract: Au nanoparticles (particle diameter ∼2 nm) prepared by thiocyanate reduction method are too small to exhibit the characteristic surface plasmon band. Addition of Rhodamine 6G (Rh 6G) to the colloidal gold solution brings about significant changes in the absorption spectrum. Two distinct peaks appear at 507 and 537 nm. Close packing of the cationic dye molecules on the gold surface induces intermolecular and intercluster interactions. Furthermore, the adsorption of the cationic dye on the gold surface results in surface charge neutralization causing the Au/dye assembly to aggregate. When the Au/Rh-6G solution was subjected to 532 nm laser pulse irradiation for long time intervals, we observed distinct changes in the absorption spectrum due to morphological changes. A growth in the particle size (5−20 nm) is observed as a result of melting and fusion of gold nanoparticles. The photoinduced morphological changes have been elucidated using picosecond laser flash photolysis. The multiphoton process leading to ...
127 citations
TL;DR: In this paper, photoinduced halide segregation in mixed halide perovskites has a direct influence on decreasing the solar cell efficiency as segregated I-rich domains serve as charge recombination centers.
Abstract: Photoinduced segregation in mixed halide perovskites has a direct influence on decreasing the solar cell efficiency as segregated I-rich domains serve as charge recombination centers. The changes in the external quantum efficiency mirror the spectral loss in the absorption; however, the time scale of the IPCE recovery in the dark is slower than the absorption recovery, showing the intricate nature of the photoinduced halide segregation and charge collection in solar cell devices.
127 citations
TL;DR: In this paper, a selective growth of gold nanoparticles on the corners of CsPbBr3 nanocrystals (NCs) is made possible with the treatment of Au(III) salts such as Au(3) bromide and Au(4) chloride in solution.
Abstract: A selective growth of gold (Au) nanoparticles on the corners of CsPbBr3 nanocrystals (NCs) is made possible with the treatment of Au(III) salts such as Au(III) bromide and Au(III) chloride in solution. The surface bound oleylamine ligands not only stabilize NCs but also facilitate reduction of the Au(III) salts followed by nucleation of the Au nanoparticles on the corners of the perovskite NCs. The luminescence quantum yield of NCs is decreased when Au nanoparticles are formed on the corners of CsPbBr3 NCs, suggesting interaction between the two systems. Formation of Au nanoparticles as well as an anion exchange is seen when Au(III) bromide was replaced with Au(III) chloride as a precursor. This simple strategy of designing perovskite–gold hybrid nanostructures with good colloidal stability offers new opportunities to explore their photocatalytic properties.
126 citations
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TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
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 …
33,785 citations
TL;DR: Two organolead halide perovskite nanocrystals were found to efficiently sensitize TiO(2) for visible-light conversion in photoelectrochemical cells, which exhibit strong band-gap absorptions as semiconductors.
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%.
16,634 citations
TL;DR: This work reviews the historical development of Transition metal dichalcogenides, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.
Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.
13,348 citations
TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
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
11,752 citations
TL;DR: Film and powders of TiO2-x Nx have revealed an improvement over titanium dioxide (TiO2) under visible light in optical absorption and photocatalytic activity such as photodegradations of methylene blue and gaseous acetaldehyde and hydrophilicity of the film surface.
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.
11,402 citations