We report the experimental demonstration of transform-limited sub-6 fs pulses at an optimal central wavelength by a tunable noncollinear optical parametric amplification（NOPA） source. Meanwhile, a white light contin...We report the experimental demonstration of transform-limited sub-6 fs pulses at an optimal central wavelength by a tunable noncollinear optical parametric amplification（NOPA） source. Meanwhile, a white light continuum in the near-infrared（NIR） range from 900 to 1100 nm is also successfully generated by focusing the unconverted800 nm beam during NOPA generation on a sapphire rod. Both visible-pump/visible-probe and visible-pump/NIR-probe experiments are realized using the same laser system. As examples, ultrafast photo-induced exciton dynamics inside two kinds of materials are investigated by the visible-pump/visible-probe and visible-pump/NIR-probe spectroscopy, respectively.展开更多
Two-dimensional(2D)titanium carbide MXene Ti_(3)C_(2) has attracted significant research interest in energy storage applications.In this study,we prepared Chl@Ti_(3)C_(2) composites by simply mixing a chlorophyll deri...Two-dimensional(2D)titanium carbide MXene Ti_(3)C_(2) has attracted significant research interest in energy storage applications.In this study,we prepared Chl@Ti_(3)C_(2) composites by simply mixing a chlorophyll derivative(e.g.,zinc methyl 3-devinyl-3-hydroxymethylpyropheophorbide a(Chl))and Ti_(3)C_(2) in tetrahydrofuran,where the Chl molecules were aggregated among the multi-layered Ti_(3)C_(2) MXene or on its surface,increasing the interlayer space of Ti_(3)C_(2).The as-prepared Chl@Ti_(3)C_(2) was employed as the anode material in the lithium-ion battery(LIB)with lithium metal as the cathode.The resulting LIB exhibited a higher reversible capacity and longer cycle performance than those of LIB based on pure Ti_(3)C_(2),and its specific discharge capacity continuously increased along with the increasing number of cycles,which can be attributed to the gradual activation of Chl@Ti_(3)C_(2) accompanied by the electrochemical reactions.The discharge capacity of 1 wt-%Chl@Ti_(3)C_(2) was recorded to be 325 mA·h·g^(-1) at the current density of 50 mA·g^(-1) with a Coulombic efficiency of 56% and a reversible discharge capacity of 173 mA·h·g^(-1) at the current density of 500 mA·g^(-1) after 800 cycles.This work provides a novel strategy for improving the energy storage performance of 2D MXene materials by expanding the layer distance with organic dye aggregates.展开更多
基金partly financially supported by the 100 Talents Program of CASthe National Basic Research Program of China(Grant No.2011CB808101)the National Natural Science Foundation of China(Grant No.61475169,61221064)
文摘We report the experimental demonstration of transform-limited sub-6 fs pulses at an optimal central wavelength by a tunable noncollinear optical parametric amplification（NOPA） source. Meanwhile, a white light continuum in the near-infrared（NIR） range from 900 to 1100 nm is also successfully generated by focusing the unconverted800 nm beam during NOPA generation on a sapphire rod. Both visible-pump/visible-probe and visible-pump/NIR-probe experiments are realized using the same laser system. As examples, ultrafast photo-induced exciton dynamics inside two kinds of materials are investigated by the visible-pump/visible-probe and visible-pump/NIR-probe spectroscopy, respectively.
基金supported by the National Natural Science Foundation of China(Grant No.11974129)to Xiao-Feng Wangthe Fundamental Research Funds for the Central Universities,Jilin University,the Science and Technology Development Plan of Jilin Province(Grant Nos.20180414010GH,20190201133JC)Japan Society for the Promotion of Science(JSPS)KAKENHI(Grant No.JP17H06436)to Hitoshi Tamiaki.
文摘Two-dimensional(2D)titanium carbide MXene Ti_(3)C_(2) has attracted significant research interest in energy storage applications.In this study,we prepared Chl@Ti_(3)C_(2) composites by simply mixing a chlorophyll derivative(e.g.,zinc methyl 3-devinyl-3-hydroxymethylpyropheophorbide a(Chl))and Ti_(3)C_(2) in tetrahydrofuran,where the Chl molecules were aggregated among the multi-layered Ti_(3)C_(2) MXene or on its surface,increasing the interlayer space of Ti_(3)C_(2).The as-prepared Chl@Ti_(3)C_(2) was employed as the anode material in the lithium-ion battery(LIB)with lithium metal as the cathode.The resulting LIB exhibited a higher reversible capacity and longer cycle performance than those of LIB based on pure Ti_(3)C_(2),and its specific discharge capacity continuously increased along with the increasing number of cycles,which can be attributed to the gradual activation of Chl@Ti_(3)C_(2) accompanied by the electrochemical reactions.The discharge capacity of 1 wt-%Chl@Ti_(3)C_(2) was recorded to be 325 mA·h·g^(-1) at the current density of 50 mA·g^(-1) with a Coulombic efficiency of 56% and a reversible discharge capacity of 173 mA·h·g^(-1) at the current density of 500 mA·g^(-1) after 800 cycles.This work provides a novel strategy for improving the energy storage performance of 2D MXene materials by expanding the layer distance with organic dye aggregates.
