Title：Mapping the structure and properties of printed nanosheet networks
Speaker：Jonathan N Coleman
Time：Sep. 28,2022 18：00
Online report（Tencent ID: 663-412-890）
Abstract：While graphene and related 2D materials are extremely exciting due to their novel properties and applications potential, producing them in large quantities and processing them into functional structures has been a challenge. However, solution processability has been achieved via the discovery of liquid phase exfoliation (LPE), a method for converting layered materials to nanosheets in liquids in a scalable way. This method yields printable inks which can be patterned into functional structures for a range of applications. Printing nanosheets onto substrates leads to the formation of nanosheet networks. These networks are disordered arrays of nanosheets that are somewhat aligned in the plane of the substrate. Typically, electrical transport in these networks is limited by inter-sheet charge transport. In turn this transport is limited by inter-sheet junctions which are controlled by the morphology of network. In this talk I will describe printing nanosheet networks for a range of device applications including strain sensors, transistors and diodes. In all cases I will demonstrate that the performance of these devices is linked to the morphology of the nanosheet network. In general, the morphology of nano networks is very hard to measure with standard methods such as X-ray tomography lacking the required resolution. Here we will discuss in new method for generating 3 dimensional images of nanosheet networks. This method involves combining SEM and FIB repeatedly image cross sections before shaving off a very thin layer and imaging again. Repeating this process up to 1000 times allows the reconstruction of the image stack to form a 3-dimensional image. From these 3D images, a range of data types can be extracted, allowing full interrogation of the network morphology. We show that this method can be applied to networks of Graphene, WS2 nanosheets as well as silver nanoplatelets and nanowires.
Brief Bio：Prof. Jonathan N Coleman is the Head of School of Physics & Professor of Chemical Physics at Trinity College Dublin. His main interest is researching chemical physics of low-dimensional nanostructures; carbon nanotubes, graphene and 2-dimensional inorganic materials. This work focuses on the exfoliation of van der Waals bonded nano-materials, leading to the formation of dispersions, suspensions and solutions of nanostructures. Such liquid processing allows the production of coatings, thin films and composites. His group work on applying these materials and methods in a number of areas including electro-mechanical sensors, printed electronics and energy storage materials. In the latter area, they have particular interest in new electrode materials for lithium-ion batteries, battery electrode architectures and the factors limiting rate performance in batteries. He has co-authored 372 peer reviewed papers in international journals such as Nature, Science, Nature Nano, Nature Materials, Nature Energy, Nature Comms etc. These journal papers have been cited a total of ~94,000 times to date and over 9500 times in 2021 alone. He has a research H-index of 118 (Google scholar). Over the last five years he has presented ~40 invited/plenary/keynote talks at international conferences, and departmental seminars. He is an inventor on numerous patents and have a Research Group of 5 postdocs and 10 postgrads.
Honors：
Clarivate (Thompson Reuters) list of highly cited researchers (2014, 2015, 2016, 2017, 2018, 2019, 2020).
TUBALL Award 2019.
ACS Nano Award Lecture Laureate 2018.
Enterprise Ireland Knowledge Transfer Awards: The License to Market Award 2016.
Elected Member of the Royal Irish Academy (MRIA) in 2015.
Kroll Medal from the Institute of Materials in 2012.
Science Foundation Ireland Researcher of the year in 2011.
The top 100 Materials Scientists of the previous decade by Thompson Reuters in 2011.
