Surface optimization of nanodiamonds using non-thermal plasma

0585411 - ÚOCHB 2025 RIV GB eng J - Journal Article
Gulka, Michal - Balasubramanian, P. - Shagieva, Ekaterina - Čopák, Jakub - Khun, J. - Scholtz, V. - Jelezko, F. - Stehlík, Štěpán - Cígler, Petr
Surface optimization of nanodiamonds using non-thermal plasma.
Carbon. Roč. 224, April (2024), č. článku 119062. ISSN 0008-6223. E-ISSN 1873-3891
R&D Projects: GA ČR(CZ) GA23-04876S; GA MŠMT EH22_008/0004558
EU Projects: European Commission(XE) 101038045 - ChemiQS
Institutional support: RVO:61388963 ; RVO:68378271
Keywords : nanodiamond * nitrogen-vacancy center * non-thermal plasma * quantum sensing * T1 spin relaxation time
OECD category: Physical chemistry; Nano-materials (production and properties) (FZU-D)
Impact factor: 10.9, year: 2022
Method of publishing: Limited access
https://doi.org/10.1016/j.carbon.2024.119062

Sensitive local monitoring of intracellular processes by quantum sensing utilizing nitrogen-vacancy (NV) centers in nanodiamonds (NDs), would greatly advance cell biology and medicine. However, NDs still fall behind in sensitivity compared to bulk diamond because of their much shorter NV relaxation times. As suggested in theoretical studies, prolongation of NV relaxation times should be achievable by surface optimization creating mixed H/O surface termination consisting of hydrogen atoms, hydroxyl groups, and C–O–C ether bridges. Here we target such chemistry by employing a non-thermal plasma (NTP) in a point-to-plain discharge configuration in aqueous solution. We have devised a set of experiments with different types of nanodiamond samples (of HPHT or detonation origin and with an H- or O-terminated surface) and four working gases (air, O2, He, and H2). Using FTIR, we have found that NTP modification induces a relative increase of O–H and C–H bonds with respect to C[dbnd]O bonds. We have observed the biggest changes in FTIR spectra and the greatest decrease in zeta potential with oxidized NDs (both detonation and HPHT) and hydrogen as the working gas. NV electron spin relaxation times of thus modified HPHT NDs indicate an improvement of the T1 time by ∼17%–∼29% and the T2 time prolongation of 40%.
Permanent Link: https://hdl.handle.net/11104/0353123