Tunable Raman spectroscopy of carbon nanotubes under high pressure

Lead Research Organisation: Queen Mary, University of London
Department Name: Physics

Abstract

The purpose of this proposal is to test the idea that the puzzling variations in the behaviour of carbon nanotubes under high pressure observed by different research groups around the world are due to Raman resonance effects. The implication is that high-pressure Raman spectroscopy of nanotubes - and indeed the study of nanotubes in different solvents - absolutely requires tunable laser excitation, so the same nanotubes (diameter and chirality) can be picked out as the conditions are changed. This would bring high-pressure Raman to a much higher degree of precision and here enable reliable and definitive high-pressure data to be obtained for single wall carbon nanotubes. As far as we are aware, no laboratory world-wide has the capabilities (tunable Raman plus high pressure) required for this programme, so the apparatus will constitute a novel, indeed unique facility. The results of this programme will have pivotal implications for the entire literature on the subject. The results will provide means of reliable testing of mechanical response of carbon nanotubes to applied stress and will provide decisive insights into interplay (and connection) between mechanical and electronic properties of nanotubes. This will provide vital information to the academic community and to workers in nanotechnology exploiting carbon nanothubes.
 
Description The nantubes which are observed by Raman spectroscopy are those that are in resonance with the exciting laser. As a first step, it was found that the effect of different solvents (water, alcohol, sulphuric acid) is change the energy of the resonance, while the effect of pressure is to shift the frequency. This opened the way to obtaining pressure coefficients independent of solvent, by tuning the laser to the same nanotubes. These experiments obtained pressure coefficients consistent with theory, if the data for graphite and graphene are re-appraised.
Exploitation Route As information revealing mechanical properties of nanotubes. For most applications of nanotubes, it is important to understand their mechanical properties and how they arise from the mechanical properties of graphite, by way of graphene.
 
Description Guest Professor Lyon 2015/2016 
Organisation Claude Bernard University Lyon 1 (UCBL)
Country France 
Sector Academic/University 
PI Contribution Ideas and designs for a novel helium-loading facility for diamond-anvils cells. Ideas and theory for interpreting their earlier data.
Collaborator Contribution Collaboration enabling my contributions above. Finding the financial side, providing Workshop facilities, finding industrial partners. Hosting me for six months (Feb - July) both in 2015 and in 2016.
Impact Papers in preparation. Equipment being built.
Start Year 2015
 
Description Guest Professor Toulouse 
Organisation Paul Sabatier University (University of Toulouse III)
Country France 
Sector Academic/University 
PI Contribution CEMES funded a two-month visit by me March/April 2014. My contribution is theoretical - we identified an interesting problem, leading to a paper currently in preparation, on the pressure dependence of Raman modes in carbon nanotubes.
Collaborator Contribution Collaborating on the theoretical problem.
Impact Paper in preparation. Not multi-disciplinary.
Start Year 2014
 
Description Summer School Lecturer 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I was invited to be one of six speakers at a Summer School on the Mechanics of Carbon Nanostructures for the International Center for Mechanical Sciences. The school ran for a week in July 2014, in Udine, Italy. Awarding Body - International Center for Mechanical Sciences, Name of Scheme - CISM Summer School

The most significant outcome, which is not offered as an option in the box below, was the book,
https://books.google.co.uk/books?id=798LCwAAQBAJ&pg=PP6&lpg=PP6&dq=Mechanics+of+Carbon+Nanostructures+CISM&source=bl&ots=J7Zrwngus7&sig=AELNG7Nw3LLlmjaycnedRvBcAmg&hl=en&sa=X&ved=0ahUKEwim8JX1rqXLAhXB1xQKHey6AOIQ6AEINDAD#v=onepage&q=Mechanics%20of%20Carbon%20Nanostructures%20CISM&f=false
Year(s) Of Engagement Activity 2014
URL http://www.cism.it/courses/C1409/lectures/