Structural rearrangements govern the various properties of disordered systems and visualization of these dynamical processes can provide critical information on structural deformation and phase transformation of the systems. However, direct imaging of individual atoms or molecules in a disordered state is quite challenging. Here, we prepare a model molecular system of C70 molecules on graphene and directly visualize the structural and dynamical evolution using aberration-corrected transmission electron microscopy. E-beam irradiation stimulates dynamics of fullerene molecules, which results in the first-order like structural transformation from the molecular crystal to molecular liquid. The real-time tracking of individual molecules using an automatic molecular identification process elucidates the relaxation behavior of a stretched exponential functional form. Moreover, the directly observed heterogeneous dynamics bear similarity to the dynamical heterogeneity in supercooled liquids near the glass transition. Fullerenes on graphene can serve as a new model system, which allows investigation of molecular dynamics in disordered phases.
Bibliographical noteFunding Information:
This work was mainly supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF-2017R1A5A1014862 and NRF-2019R1C1C1003643) and grants from the Institute for Basic Science (IBS-R006-D1). C. U.K. acknowledges support from the National Research Foundation of Korea (NRF) funded by the Korea government (NRF-2016R1A5A1013277 and NRF-2014R1A2A1A11051254). Y.K. acknowledges support from the National Research Foundation of Korea (NRF-2014R1A1A1002667) and from UNIST (1.180016.01). J.P. acknowledges support from the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2017R1C1B2010434 and NRF-2017R1A5A1015365), the support program by MOTIE (Ministry of Trade, Industry & Energy) and KRSC (Korea Semiconductor Research Consortium) for the development of future semiconductor devices (No. 10080657), and IBS-R006-D1.
© 2019, The Author(s).
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)