Odborná přednáška hostujícího vědce

Na pozvání Dr. Martina Veselého z našeho ústavu proběhla v pátek 29.4.2022 přednáška 

Nanoscale chemical imaging of 2D materials using tip-enhanced optical spectroscopy

Dr. Naresh Kumar, ETH Zurich

In the last decade, tip-enhanced optical spectroscopy has emerged as a powerful analytical tool for hyperspectral chemical imaging of 2D materials at the nanoscale. In this talk, I will present the basic principles of tip-enhanced optical spectroscopy and discuss how tip-enhanced Raman spectroscopy (TERS) can be used to visualize structural defects in pristine single-layer graphene [1,2] and determine the level and location of molecular disorder in chemically functionalized few-layer graphene [3], carboxyl-modified graphene oxide [4] and graphene nanoribbons [5]. Furthermore, application of hyperspectral tip-enhanced photoluminescence (TEPL) microscopy to probe excitonic processes in single-layer MoS2 [6], visualize optoelectronic behavior of grain boundaries grain boundaries in singlelayer WSe2 [7] and probe nanoscale exciton funneling at wrinkles of twisted bilayer MoS2 [8] will be presented.

References
1. S. Mignuzzi, N. Kumar, B. Brennan, I. S. Gilmore, D. R. Richards, A. J. Pollard, D. Roy “Probing individual point defects in graphene via near-field Raman scattering” Nanoscale 2015, 9, 19413-19418
2. W. Su†, N. Kumar†, N. Dai, D. Roy “Nanoscale chemical mapping of intrinsic defects in graphene using tipenhanced Raman spectroscopy” Chemical Communications 2016, 52, 8227-8230
3. E. L. Legge, K. R. Paton, M. Wywijas, G. McMahon, R. Pemberton, N. Kumar et al. “Determining the level and location of functional groups on few-layer graphene and their effect on the mechanical properties of nanocomposites” ACS Applied Materials & Interfaces, 2020, 12, 13481-13493
4. W. Su, N. Kumar, A. Krayev, M. Chaigneau “In situ topographical chemical and electrical imaging of carboxyl graphene oxide at the nanoscale Nature Communications 2018, 9: 2891
5. W. Su, A. Esfandiar, O. Lancry, J. Shao, N. Kumar, M. Chaigneau "Visualising structural modification of patterned graphene nanoribbons using tip-enhanced Raman spectroscopy" Chemical Communications, 2021, 57, 6895-6898
6. W. Su†, N. Kumar†, S. Mignuzzi, J. Crain, D. Roy “Nanoscale mapping of excitonic processes in single layer MoS2 using tip-enhanced photoluminescence microscopy” Nanoscale 2016, 8, 10564-10569
7. W. Su, N. Kumar, H. Shu, O. Lancry, M. Chaigneau “In situ Visualization of Optoelectronic Behavior of Grain Boundaries in Monolayer WSe2 at the Nanoscale” The Journal of Physical Chemistry C, 2021, 125, 26883-26891
8. J. Shao, F. Chen, W. Su, N. Kumar, Y. Zeng, L. Wu, H. W. Lu “Probing Nanoscale Exciton Funneling at Wrinkles of Twisted Bilayer MoS2 Using Tip-Enhanced Photoluminescence Microscopy” The Journal of Physical Chemistry Letters, 2022, 13, 3304-3309