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
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TL;DR: The focus of this study is to establish a stability window for electrochemical tests for all-inorganic CsPbBr3 and hybrid organic–inorganic MAPbI3 perovskites, and to understand the reduction and oxidation events that occur and to assess the damage done during these processes at extreme electrochemical conditions.
Abstract: The unique optoelectronic properties of lead halide perovskites have triggered a new wave of excitement in materials chemistry during the past five years. Electrochemistry, spectroelectrochemistry, and photoelectrochemistry could be viable tools both for analyzing the optoelectronic features of these materials and for assembling them into hybrid architectures (e.g., solar cells). At the same time, the instability of these materials limits the pool of solvents and electrolytes that can be employed in such experiments. The focus of our study is to establish a stability window for electrochemical tests for all-inorganic CsPbBr3 and hybrid organic–inorganic MAPbI3 perovskites. In addition, we aimed to understand the reduction and oxidation events that occur and to assess the damage done during these processes at extreme electrochemical conditions. In this vein, we demonstrated the chemical, structural, and morphological changes of the films in both reductive and oxidative environments. Taking all these result...
86 citations
TL;DR: In this paper, the surface of an optically transparent electrode has been modified with colloidal particles of ZnO and CdS. The role of the coupled semiconductor in improving the photon to photocurrent conversion efficiency of the photosensitization process is described.
85 citations
TL;DR: Detailed assessment of the roles of O2, H2O2, *OH, and O2-* in the TiO2 assisted photocatalytic oxidation (PCO) of arsenite shows oxidation rates comparable to those observed under oxygen saturation, implying the primary role of oxygen is as a scavenger of the conduction band electron.
Abstract: We report herein a detailed assessment of the roles of O2, H2O2, •OH, and O2-• in the TiO2 assisted photocatalytic oxidation (PCO) of arsenite. Although both arsenite, As(III), and arsenate, As(V), adsorb extensively onto the surface of TiO2, past studies relied primarily on the analysis of the arsenic species in solution, neglecting those adsorbed onto the surface of TiO2. We used extraction and analyses of the arsenic species adsorbed onto the surface of the TiO2 to illustrate that the oxidation of As(III) to As(V) occurs in an adsorbed state during TiO2 PCO. The TiO2 photocatalytic oxidation (PCO) of surface adsorbed As(III) in deoxygenated solutions with electron scavengers, Cu2+, and polyoxometalates (POM) yields oxidation rates that are comparable to those observed under oxygen saturation, implying the primary role of oxygen is as a scavenger of the conduction band electron. Pulse radiolysis and competition kinetics were employed to determine a rate constant of 3.6 × 106 M-1 s-1 for the reaction of ...
84 citations
TL;DR: In this article, two new pyrrolidinofullerenes, 1 and 2, have been synthesized and their photophysical properties have been investigated, and their singlet and triplet excited states have been examined with picosecond and nanosecond laser flash photolysis.
Abstract: Two new pyrrolidinofullerenes, 1 and 2, have been synthesized, and their photophysical properties have been investigated. The pyrrolidinofullerene 1 has three phenyl groups attached to the 1, 2, and 5 positions of the pyrrolidine ring. The pyrrolidinofullerene 2, on the other hand, has a flexible attachment with an N-methylaniline end group and is the prototype of a fullerene-aniline dyad. Singlet and triplet excited-state properties of these two functionalized fullerene derivatives have been examined with picosecond and nanosecond laser flash photolysis. The singlet and triplet excited states of these fullerenes exhibit characteristic absorption bands in the vis-IR region of the spectrum. The functionalization of C 60 with pyrrolidine groups shift the excited-state absorption maxima to the blue. Three different quenchers, O 2 , TEMPO, and ferrocene, are employed to investigate the reactivity of triplet excited states. The bimolecular quenching rate constants determined for these quenchers were in the range of 5.3 × 10 8 to 7.7 × 10 9 M -1 s -1 . The excited-state interactions of these functionalized fullerenes are compared to that of C 60 .
82 citations
TL;DR: In this paper, the electron injection into TiO2 was found to dominate the deactivation of the excited singlet state and the rate constant for the charge injection process as determined from the decay of the singlet is ∼1011 s-1.
Abstract: TiO2 and Ag@TiO2 core shell nanoparticles have been modified with a carbocyanine dye (IR-125) to extend the photoresponse in the near-infrared. Upon binding dye molecules to TiO2, we observe a sharp decrease in the fluorescence yield. The electron injection into TiO2 was found to dominate the deactivation of the excited singlet state. The rate constant for the charge injection process as determined from the decay of the excited singlet is ∼1011 s-1. In the case of Ag@TiO2, the electrons injected into the TiO2 layer are quickly transferred to the Ag core. The metal core in Ag@TiO2 did not alter the forward charge-transfer kinetics, but it influenced the back electron transfer. The regeneration of the dye involving the reaction between the oxidized dye and injected electron was a factor of 2 slower for Ag@TiO2 than the TiO2 system. Use of composite nanoparticles comprised of a metal core semiconductor shell may provide new ways to modulate charge recombination processes in dye-sensitized solar cells.
82 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