scispace - formally typeset
Search or ask a question
Topic

Photoexcitation

About: Photoexcitation is a research topic. Over the lifetime, 5874 publications have been published within this topic receiving 134733 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: The IrO2-loaded SrTiO3 doped with rhodium and antimony synthesized by a conventional solid-state reaction splits water under visible light and simulated sunlight irradiation giving 0.1% of the apparent quantum yield at 420 nm is the longest among achieved photocatalytic water splitting with one-step photoexcitation.

178 citations

Journal ArticleDOI
TL;DR: A theoretical investigation of the optical response and of the excited-state properties of three-arm and four-arm phenyl-cored dendrimers for photovoltaic applications and calculated reorganization energies were found to correlate well with the device photocurrent data where available.
Abstract: π-Conjugated dendrimers are an important class of materials for optoelectronic devices, especially for light-harvesting systems. We report here a theoretical investigation of the optical response and of the excited-state properties of three-arm and four-arm phenyl-cored dendrimers for photovoltaic applications. A variety of theoretical methods are used and evaluated against each other to calculate vertical transition energies, absorption and excitation spectra with vibronic structure, charge transport, and excitonic behavior upon photoexcitation and photoemission processes. Photophysical phenomena in these dendrimers are, in general, better explained with ab initio methods rather than with semiempirical techniques. Calculated reorganization energies were found to correlate well with the device photocurrent data where available. The excitons formed during photoexcitation are calculated to be more delocalized than the ones formed after vibrational relaxation in the excited states for fluorescence emission. ...

178 citations

Journal ArticleDOI
TL;DR: It is found that the dynamics of the ultrafast carrier dynamics in single-walled carbon nanotubes are dependent on excitation intensity and the electronic transitions initially excited.
Abstract: Ultrafast carrier dynamics in individual semiconducting single-walled carbon nanotubes was studied by femtosecond transient absorption and fluorescence measurements. After photoexcitation of the second van Hove singularity of a specific tube structure, the relaxation of electrons and holes to the fundamental band edge occurs to within 100 fs. The fluorescence decay from this band is dependent on the excitation density and can be rationalized by exciton annihilation theory. In contrast to fluorescence, the transient absorption has a distinctly different time and intensity dependence for different tube structures, suggesting a branching to emissive and trap states following photoexcitation.

177 citations

Journal ArticleDOI
TL;DR: Predominantly excitons, with near-unity quantum efficiency, are generated on excitation, while only a very small fraction of free charges are initially excited, consistent with rapid hot exciton dissociation.
Abstract: We determine the efficiencies for the formation of excitons and charge carriers following ultrafast photoexcitation of a semiconducting polymer (MEH-PPV). The simultaneous, quantitative determination of exciton and charge photoyields is achieved through subpicosecond studies of both the real and the imaginary components of the complex conductivity over a wide frequency range. Predominantly excitons, with near-unity quantum efficiency, are generated on excitation, while only a very small fraction ($l{10}^{\ensuremath{-}2}$) of free charges are initially excited, consistent with rapid ($\ensuremath{\sim}100\text{ }\text{ }\mathrm{fs}$) hot exciton dissociation. These initial charges are very short lived, decaying on subpicosecond time scales.

174 citations

Journal ArticleDOI
TL;DR: It is argued that the activation enthalpy reduction is directly related to the photoelectrochemical potential built-up on the Au nanoparticle under steady-state light excitation, analogous to electrochemical activation.
Abstract: The activation energy of a catalytic reaction serves not only as a metric of the efficacy of a catalyst but also as a potential indicator of mechanistic differences between the catalytic and noncatalytic reaction. However, activation energies are quite underutilized in the field of photocatalysis. We characterize in detail the effect of visible light excitation on the activation enthalpy of an electron transfer reaction photocatalyzed by plasmonic Au nanoparticles. We find that in the presence of visible light photoexcitation, the activation enthalpy of the Au nanoparticle-catalyzed electron transfer reaction is significantly reduced. The reduction in the activation enthalpy depends on the excitation wavelength, the incident laser power, and the strength of a hole scavenger. On the basis of these results, we argue that the activation enthalpy reduction is directly related to the photoelectrochemical potential built-up on the Au nanoparticle under steady-state light excitation, analogous to electrochemical...

172 citations


Network Information
Related Topics (5)
Raman spectroscopy
122.6K papers, 2.8M citations
92% related
Band gap
86.8K papers, 2.2M citations
91% related
Amorphous solid
117K papers, 2.2M citations
87% related
Graphene
144.5K papers, 4.9M citations
86% related
Thin film
275.5K papers, 4.5M citations
86% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023249
2022529
2021221
2020204
2019183
2018256