Topic
Photoexcitation
About: Photoexcitation is a research topic. Over the lifetime, 5874 publications have been published within this topic receiving 134733 citations.
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TL;DR: In this paper, a two-step photoexcitation mechanism was proposed, whereby the Pt-TiO 2 served as a photocatalyst for H 2 evolution, the NO 3 - / NO 2 - couple serves as a redox mediator, and O 2 evolution occurs via direct photo-excitation of NO 3 ion.
43 citations
TL;DR: In this paper, the authors reported ultrafast transient grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd3As2, at both room temperature and 80 K.
Abstract: We report ultrafast transient-grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd3As2, at both room temperature and 80 K. After photoexcitation with 1.5-eV photons, charge-carriers relax by two processes, one of duration 500 fs and the other of duration 3.1 ps. By measuring the complex phase of the change in reflectance, we determine that the faster signal corresponds to a decrease in absorption, and the slower signal to a decrease in the light's phase velocity, at the probe energy. We attribute these signals to electrons' filling of phase space, first near the photon energy and later at lower energy. We attribute their decay to cooling by rapid emission of optical phonons, then slower emission of acoustic phonons. We also present evidence that both the electrons and the lattice are strongly heated.
43 citations
TL;DR: The protein environment was found to enhance the bond length alternation (BLA) of the retinyl chain and blueshift the first absorption maxima of the protonated Schiff base in the BC and Rh models relative to the chromophore in the gas phase, thus improving the quantum yield of the photoexcitation process.
Abstract: Retinal is the photon absorbing chromophore of rhodopsin and other visual pigments, enabling the vertebrate vision process. The effects of the protein environment on the primary photoexcitation pro...
43 citations
TL;DR: In this paper, the Coulomb blockade oscillations around the few-electron regime in an asymmetric Si single-electron transistor were investigated, and a novel type of photocurrent was observed, which can be attributed to the interplay of photogenerated holes and singleelectron tunneling via the island.
Abstract: We observed a novel type of photocurrent by investigating Coulomb blockade oscillations around the few-electron regime in an asymmetric Si single-electron transistor. Photoexcitation generates new current peaks below the threshold voltage only for one polarity of source-drain voltage. Under low excitation, such photocurrent exhibits intermittent behavior with sudden drops and rises. The phenomena can be ascribed to the interplay of photogenerated holes and single-electron tunneling via the island. The sudden drop is a manifestation of single-electron recombination with a hole in the island.
43 citations
TL;DR: This finding allows the treatment of plasmonic excitation as a reagent in chemical reactions; the chemical potential of this reagent is tunable by the light intensity.
Abstract: By the photoexcitation of localized surface plasmon resonances of metal nanoparticles, one can generate reaction equivalents for driving redox reactions. We show that, in such cases, there is a chemical potential contributed by the plasmonic excitation. This chemical potential is a function of the concentration of light, as we determine from the light-intensity-dependent activity in the plasmon-excitation-driven reduction of CO2 on Au nanoparticles. Our finding allows the treatment of plasmonic excitation as a reagent in chemical reactions; the chemical potential of this reagent is tunable by the light intensity.
43 citations