Search

Your search keyword '"Liu, Weimin"' showing total 4,638 results
Start Over Author "Liu, Weimin"
4,638 results on '"Liu, Weimin"'

113. Investigation of ultrafast intermediate states during singlet fission in lycopene H-aggregate using femtosecond stimulated Raman spectroscopy.

Author

Peng, Bo, Wang, Ziyu, Jiang, Jiaming, Huang, Yifan, and Liu, Weimin

Subjects
LYCOPENE, RAMAN spectroscopy, SOLAR cell efficiency, CHEMICAL fingerprinting, ENERGY consumption, POTENTIAL energy
Abstract

The singlet fission process involves the conversion of one singlet excited state into two triplet states, which has significant potential for enhancing the energy utilization efficiency of solar cells. Carotenoid, a typical π conjugated chromophore, exhibits specific aggregate morphologies known to display singlet fission behavior. In this study, we investigate the singlet fission process in lycopene H-aggregates using femtosecond stimulated Raman spectroscopy aided by quantum chemical calculation. The experimental results reveal two reaction pathways that effectively relax the S2 (11Bu+) state populations in lycopene H-aggregates: a monomer-like singlet excited state relaxation pathway through S2 (11Bu+) → 11Bu− → S1 (21Ag−) and a dominant sequential singlet fission reaction pathway involving the S2 (11Bu+) state, followed by S* state, a triplet pair state [1(TT)], eventually leading to a long lifetime triplet state T1. Importantly, the presence of both anionic and cationic fingerprint Raman peaks in the S* state is indicative of a substantial charge-transfer character. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

114. Terahertz emission in the van der Waals magnet CrSiTe3

Author

Suo, Peng, Xia, Wei, Zhang, Wenjie, Zhu, Xiaoqing, Fu, Jibo, Lin, Xian, Jin, Zuanming, Liu, Weimin, Guo, Yanfeng, and Ma, Guohong

Subjects
Physics - Optics, Condensed Matter - Strongly Correlated Electrons
Abstract

The van der Waals magnet CrSiTe3 (CST) has captured immense interest because it is capable of retaining the long-range ferromagnetic order even in its monolayer form, thus offering potential use in spintronic devices. Bulk CST crystal has inversion symmetry that is broken on the crystal surface. Here, by employing ultrafast terahertz (THz) emission spectroscopy and time resolved THz spectroscopy, the THz emission of the CST crystal was investigated, which shows a strong THz emission from the crystal surface under femtosecond (fs) pulse excitation at 800 nm. Theoretical analysis based on space symmetry of CST suggests the dominant role of shift current occurring on the surface with a thickness of a few quintuple layers in producing the THz emission, in consistence with the experimental observation that the emitted THz amplitude strongly depends on the azimuthal and pumping polarization angles. The present study offers a new efficient THz emitter as well as a better understanding of the nonlinear optical response of CST. It hopefully will open a window toward the investigation on the nonlinear optical response in the mono-/few-layer van der Waals crystals with low-dimensional magnetism., Comment: 36 pages, 6 figures

Published
2019

Catalog

Books, media, physical & digital resources
See catalog results