Previously, we have discussed in detail the near-field Raman spectroscopy (Shi L., et al. Nature Materials, 15, 634-639, 2016), resonance Raman spectroscopy (Shi L., et al. Nano Letters, 21 , 1096–1101, 2021), anti-Stokes Raman spectroscopy (Tschannen CD, et al. ACS Nano, 15, 7, 12249–12255 2021), and Raman scattering cross section (Tschannen CD, et al. Nano Letters; 20, 6750−6755, 2020)) of one-dimensional linear carbon chains confined inside carbon nanotubes. Recently, we have cooperated with researchers from the University of Cologne and other universities to apply time-resolved Raman spectroscopy to explore the exciton relaxation dynamics in one-dimensional carbon chains.

    Excited by a picosecond laser, the relaxation time in Raman spectrum of one-dimensional carbon chains is much longer than that of a quasi-one-dimensional carbon nanotube, indicating the specificity of the one-dimensional structure. Using a steady-state laser far from the resonance region to excite the carbon chain, the Raman signal of the carbon chain usually cannot be observed; while using the picosecond laser with the same energy to excite the carbon chain, a strong Raman signal of carbon chain  can be seen. Based on this, we propose a hypothesis that there is a strong energy transfer between carbon nanotubes and carbon chains, which affects their excitonic dynamics. In order to verify this hypothesis, we confirmed the existence of energy transfer by comparing the phonon relaxation kinetics of carbon nanotubes and carbon chains. In addition, the observed temperature dependence of the dynamics show that the exciton recombination is dominated by defects and optical phonon-assisted processes, whereas the power dependent experiments showed that exciton-exciton recombination does not play any significant role. Our research has improved people's understanding of the interaction between allotropes of carbon in different dimensions. This research method is also applicable to most one-dimensional and two-dimensional material exciton dynamics studies.

    Paper information: Jingyi Zhu*, Robin Bernhardt, Weili Cui, Raphael German, Julian Wagner, Boris V. Senkovskiy, Alexander Grüneis, Thomas Pichler, Rulin Liu, Xi Zhu, Paul HM Van Loosdrecht* and Lei Shi*. Unraveling the excitonic transition and associated dynamics in confined long linear carbon-chains with time-resolved resonance Raman scattering. Laser & Photonics Reviews 2100259 (2021)

    Link to the paper: https://doi.org/10.1002/lpor.202100259