Quantitative measurement of graphitic sp2 on single nanodiamonds with sub-monolayer sensitivity using differential interference contrast and photo-thermal microscopy

Hamilton, Samuel, Regan, David ORCID: https://orcid.org/0000-0003-0420-3481, Payne, Lukas, Borri, Paola ORCID: https://orcid.org/0000-0002-7873-3314 and Langbein, Wolfgang ORCID: https://orcid.org/0000-0001-9786-1023 2024. Quantitative measurement of graphitic sp2 on single nanodiamonds with sub-monolayer sensitivity using differential interference contrast and photo-thermal microscopy. Carbon 228 , 119371. 10.1016/j.carbon.2024.119371

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

The surface of nanodiamonds is prone to be decorated with a graphitic layer due to the thermodynamic instability of diamond versus graphite. Notably, this surface layer affects the zeta-potential of nanodiamonds controlling their colloidal stability, modulates the charging of embedded nitrogen vacancy centres used for sensing and quantum technology, and introduces an optical absorption which leads to heating and destruction of nanodiamonds under intense laser irradiation. Physical and chemical treatments to reduce the graphitic carbon are available, but a sensitive method to measure this graphitic layer on single nanodiamonds is lacking. Here, we demonstrate a non-destructive method to quantitatively determine the graphitic carbon correlatively with the nanodiamond size, on individual nanodiamonds. The method allows determining the fraction of graphitic sp to diamond sp bonded atoms, and estimating the sp surface layer thickness. We investigated milled nanodiamonds, both untreated and chemically treated to remove sp . We found that untreated nanodiamonds were covered by the equivalent of a single monolayer, which was reduced to 10% of a monolayer for treated nanodiamonds. In both cases, significant variations between individual nanodiamonds were observed. The minimum number of bonded atoms detectable under the measurement conditions reported here was found to be .

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy Biosciences
Publisher:	Elsevier
ISSN:	0008-6223
Date of First Compliant Deposit:	15 July 2024
Date of Acceptance:	18 June 2024
Last Modified:	25 Jul 2024 11:38
URI:	https://orca.cardiff.ac.uk/id/eprint/170605

Actions (repository staff only)

Edit Item