This letter reports an all-optical measurement of laser electric field based on strong field ionization.By measuring the attosecond transient absorption spectra of krypton ions subjected to strong laser fields,we obta...This letter reports an all-optical measurement of laser electric field based on strong field ionization.By measuring the attosecond transient absorption spectra of krypton ions subjected to strong laser fields,we obtain the time-dependent effective valence-hole population,from which the driving laser waveform is retrieved with particle swarm optimization and genetic algorithm under strong-field approximation.展开更多
Exploiting a synthesis protocol to tailor TiO_(2)with a unique morphology and crystal phase has received considerable interest in the energy and environmental fields.We here describe the use of a titanium glycolate pr...Exploiting a synthesis protocol to tailor TiO_(2)with a unique morphology and crystal phase has received considerable interest in the energy and environmental fields.We here describe the use of a titanium glycolate precursor in a hydrothermal hydrolysis reaction to engineer TiO_(2)nanocrystals with different crystal phases and structures.Anatase TiO_(2)nanocrystals with twinned structures were obtained by using a lower amount of NaOH in the hydrolysis system,while brookite TiO_(2)nanocrystals were formed when higher amounts of NaOH were employed.The as-synthesized different TiO_(2)nanocrystals have a suitable bandgap to harvest photons and a more negative bottom level of the conduction band than the redox potential of H^(+)/H_(2)indicating their potential as hydrogen-evolution semiconductor photocatalysts.However,the TiO_(2)nanotwins show promoted charge separation efficiency,and thus result in superior photocatalytic H_(2)generation activity compared to the anatase and brookite TiO_(2)nanocrystals.Our findings provide an effective and versatile solution for the fabrication of TiO_(2)-based nanostructures with different phases and morphologies through chemical conversion of powder precursor nanoparticles,which could pave the way to the design of other functional nano-oxides with unique structures.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12234020,12450403,and 12374263)。
文摘This letter reports an all-optical measurement of laser electric field based on strong field ionization.By measuring the attosecond transient absorption spectra of krypton ions subjected to strong laser fields,we obtain the time-dependent effective valence-hole population,from which the driving laser waveform is retrieved with particle swarm optimization and genetic algorithm under strong-field approximation.
基金supported by the National Natural Science Foundation of China(21501137)Department of Education of Hubei Province under the project of Science and Technology Innovation Team of Outstanding Young and Middle-aged Scientists(T201606).
文摘Exploiting a synthesis protocol to tailor TiO_(2)with a unique morphology and crystal phase has received considerable interest in the energy and environmental fields.We here describe the use of a titanium glycolate precursor in a hydrothermal hydrolysis reaction to engineer TiO_(2)nanocrystals with different crystal phases and structures.Anatase TiO_(2)nanocrystals with twinned structures were obtained by using a lower amount of NaOH in the hydrolysis system,while brookite TiO_(2)nanocrystals were formed when higher amounts of NaOH were employed.The as-synthesized different TiO_(2)nanocrystals have a suitable bandgap to harvest photons and a more negative bottom level of the conduction band than the redox potential of H^(+)/H_(2)indicating their potential as hydrogen-evolution semiconductor photocatalysts.However,the TiO_(2)nanotwins show promoted charge separation efficiency,and thus result in superior photocatalytic H_(2)generation activity compared to the anatase and brookite TiO_(2)nanocrystals.Our findings provide an effective and versatile solution for the fabrication of TiO_(2)-based nanostructures with different phases and morphologies through chemical conversion of powder precursor nanoparticles,which could pave the way to the design of other functional nano-oxides with unique structures.
