Atomically-Thin 2D Materials: a Versatile Platform for Nanofluidics and Nanophotonics
Event details
| Date | 06.03.2020 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Aleksandra Radenovic, Institute of Bioengineering, School of Engineering, EPFL, Lausanne (CH) |
| Location | |
| Category | Conferences - Seminars |
BIOENGINEERING SEMINAR
Abstract:
The advent of atomically-thin 2D materials such as graphene, hexagonal boron nitride (hBN) and molybdenum disulphide (MoS2), to name a few, has enabled investigation of physical processes at ultimate scales. In my laboratory, using atomically-thin 2D materials we explore two research avenues at the nanoscale: nanofluidics and nanophotonics.
In the first part of my talk, I will introduce nanopores formed in a monolayer of MoS2 and highlight recent experimental and theoretical developments that propelled the development of nanoscale devices allowing low-cost single-molecule analysis and osmotic energy harvesting. Both applications take advantage of quasi-2D nature of MoS2 membrane. Even for the very small pore sizes, relatively high ionic currents are obtained due to the fact that the ionic current through a nanopore is inversely proportional to the thickness of the membrane. Advances in the large area growth of the MoS2 opened the door for the applications that go beyond single pore experiments while the use of light further boosted their impressive performance at water–energy nexus.
In the second part of the talk, I will introduce nanophotonics applications focusing on the atomic defects in hBN that room-temperature single-photon emitters. The advent of single quantum emitters in 2D materials offers new opportunities to construct a scalable quantum architecture. Transmission electron microscopy TEM, SPM or confocal microscopy techniques are not ideal for fast, high-throughput, in-situ imaging of defects in 2D materials with nanometer resolution. There is a clear demand for the development of advanced optical technology that images individual defects at better temporal, spectral and spatial resolutions. We have explored the single-molecule localization microscopy to characterize defects in hBN. In addition to the precise location of the optically active defects we record as well their spectral properties using spectral SMLM. As localization microscopy allows imaging in a liquid environment, we were also able to resolve for the first time the transport of single proton charges at the surface of hexagonal boron nitride crystals immersed in water. Our approach relies on the successive activation of optically-active surface defects through protonation events, permitting us to make direct optical visualization of the trajectories of individual charges at the surface of the crystal, with nanometric resolution and over micrometer range. This technique reveals proton trajectories as a succession of jumps between proton-binding defects, mediated by interfacial water. Our experiments thus demonstrate the potential of super-resolution techniques for the investigation of material science, chemistry and soft matter at the molecular scale, opening up on a number of avenues related to the interplay of flow or confinement on molecular charge transport at interfaces.
Bio:
Prof. Aleksandra Radenovic is an associate professor at EPFL, School of Engineering (STI), in the Institute of Bioenginnering where she started leading the Laboratory of Nanoscale Biology (LBEN) in 2008. Her lab works in the research field that can be termed single molecule biophysics. . She received her Ph.D. in Biophysics from University of Lausanne (Switzerland.) in 2003 and a Msc. in Physics from University of Zagreb (Croatia) in 2000. She has received an European Research Council (ERC) Starting Grant in 2010, and SNF Backup scheme Consolidator Grant (2015). She is also recipient of CCMX materials challenge aword in 2015. She develops techniques and methodologies based on optical imaging, bio-sensing and single-molecule manipulation with the aim to monitor the behavior of individual biological molecules and complexes in vitro and in live cells.
Zoom link for attending remotely: https://epfl.zoom.us/j/286789148
Abstract:
The advent of atomically-thin 2D materials such as graphene, hexagonal boron nitride (hBN) and molybdenum disulphide (MoS2), to name a few, has enabled investigation of physical processes at ultimate scales. In my laboratory, using atomically-thin 2D materials we explore two research avenues at the nanoscale: nanofluidics and nanophotonics.
In the first part of my talk, I will introduce nanopores formed in a monolayer of MoS2 and highlight recent experimental and theoretical developments that propelled the development of nanoscale devices allowing low-cost single-molecule analysis and osmotic energy harvesting. Both applications take advantage of quasi-2D nature of MoS2 membrane. Even for the very small pore sizes, relatively high ionic currents are obtained due to the fact that the ionic current through a nanopore is inversely proportional to the thickness of the membrane. Advances in the large area growth of the MoS2 opened the door for the applications that go beyond single pore experiments while the use of light further boosted their impressive performance at water–energy nexus.
In the second part of the talk, I will introduce nanophotonics applications focusing on the atomic defects in hBN that room-temperature single-photon emitters. The advent of single quantum emitters in 2D materials offers new opportunities to construct a scalable quantum architecture. Transmission electron microscopy TEM, SPM or confocal microscopy techniques are not ideal for fast, high-throughput, in-situ imaging of defects in 2D materials with nanometer resolution. There is a clear demand for the development of advanced optical technology that images individual defects at better temporal, spectral and spatial resolutions. We have explored the single-molecule localization microscopy to characterize defects in hBN. In addition to the precise location of the optically active defects we record as well their spectral properties using spectral SMLM. As localization microscopy allows imaging in a liquid environment, we were also able to resolve for the first time the transport of single proton charges at the surface of hexagonal boron nitride crystals immersed in water. Our approach relies on the successive activation of optically-active surface defects through protonation events, permitting us to make direct optical visualization of the trajectories of individual charges at the surface of the crystal, with nanometric resolution and over micrometer range. This technique reveals proton trajectories as a succession of jumps between proton-binding defects, mediated by interfacial water. Our experiments thus demonstrate the potential of super-resolution techniques for the investigation of material science, chemistry and soft matter at the molecular scale, opening up on a number of avenues related to the interplay of flow or confinement on molecular charge transport at interfaces.
Bio:
Prof. Aleksandra Radenovic is an associate professor at EPFL, School of Engineering (STI), in the Institute of Bioenginnering where she started leading the Laboratory of Nanoscale Biology (LBEN) in 2008. Her lab works in the research field that can be termed single molecule biophysics. . She received her Ph.D. in Biophysics from University of Lausanne (Switzerland.) in 2003 and a Msc. in Physics from University of Zagreb (Croatia) in 2000. She has received an European Research Council (ERC) Starting Grant in 2010, and SNF Backup scheme Consolidator Grant (2015). She is also recipient of CCMX materials challenge aword in 2015. She develops techniques and methodologies based on optical imaging, bio-sensing and single-molecule manipulation with the aim to monitor the behavior of individual biological molecules and complexes in vitro and in live cells.
Zoom link for attending remotely: https://epfl.zoom.us/j/286789148
Practical information
- Informed public
- Free
Organizer
Contact
- Institute of Bioengineering (IBI), Christina Mattsson