Solution-phase fluorination of nanodiamond: near-surface NV- activation and spin relaxation
Abstract
Nanodiamonds hosting luminescent point defects, known as fluorescent nanodiamonds (FND), are a leading platform for quantum technology. The nitrogen-vacancy (NV) centre is the most intensively studied of these; its negatively charged state (NV-) can serve as a qubit at room temperature, and its stability is governed by surface functional groups. We present two solution-phase fluorination routes for stabilising NV-: direct C-F bond formation by decarboxylation with xenon difluoride via a radical mechanism, and the Balz-Schiemann reaction, which replaces surface amino groups with fluorine. The two routes were compared by infrared, X-ray photoelectron, energy-dispersive X-ray, Raman and photoluminescence spectroscopy. Both gave a high NV- fraction, up to ∼85% on average, which to our knowledge is among the highest reported for surface-terminated nanodiamonds of this size and, in particular, for fluorine termination. We attribute the stabilisation to the fluorination treatment, which removes acceptor-like carboxyl groups and forms C-F bonds that give the surface a positive electron affinity. Frequency-domain relaxometry shows that the fluorinated particles retain a long spin-lattice relaxation time, 733±56 and 712±20 μs for the XeF2 and Balz-Schiemann routes, several times the values reported for commercial HPHT nanodiamonds, although shorter than the 1173±123 μs of the as-received material. Fluorination thus activates near-surface NV- centres, which dominate relaxometric sensing, at the cost of a moderate shortening of T1.
Related
- Dual-Kinetic Relaxation Spectroscopy for Discrimination of Volatile Organic Mixtures via Finite-Size Surface Gratings
- Neural Field Ensembles for Aerodynamic Surface Prediction: Winning Solution to the ONERA CRM Wall Distribution 2025 Challenge
- Optical activation of nonlinear Hall effect in topological insulators with warped Fermi surface
- Nanodiamond Sensing of Stray Fields during Domain Reversal
- Graphene-nanodiamond membranes for atomic-impact sensing: design and fluorescence readout limits
BibTeX
@misc{czene2026solutionphase,
title = {{Solution-phase fluorination of nanodiamond: near-surface NV$^-$ activation and spin relaxation}},
author = {Szabolcs Czene and Olga Krafcsik and Nikoletta Jegenyés and Dávid Beke and László Péter and Vladimir Verkhovlyuk and Adam Gali},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.06605},
eprint = {2609.06605},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.06605},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Solution-phase fluorination of nanodiamond: near-surface NV^- activation and spin relaxation
AU - Szabolcs Czene
AU - Olga Krafcsik
AU - Nikoletta Jegenyés
AU - Dávid Beke
AU - László Péter
AU - Vladimir Verkhovlyuk
AU - Adam Gali
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2609.06605
UR - https://arxiv.org/abs/2609.06605
AB - Nanodiamonds hosting luminescent point defects, known as fluorescent nanodiamonds (FND), are a leading platform for quantum technology. The nitrogen-vacancy (NV) centre is the most intensively studied of these; its negatively charged state (NV^-) can serve as a qubit at room temperature, and its stability is governed by surface functional groups. We present two solution-phase fluorination routes for stabilising NV^-: direct C-F bond formation by decarboxylation with xenon difluoride via a radical mechanism, and the Balz-Schiemann reaction, which replaces surface amino groups with fluorine. The two routes were compared by infrared, X-ray photoelectron, energy-dispersive X-ray, Raman and photoluminescence spectroscopy. Both gave a high NV^- fraction, up to ∼85% on average, which to our knowledge is among the highest reported for surface-terminated nanodiamonds of this size and, in particular, for fluorine termination. We attribute the stabilisation to the fluorination treatment, which removes acceptor-like carboxyl groups and forms C-F bonds that give the surface a positive electron affinity. Frequency-domain relaxometry shows that the fluorinated particles retain a long spin-lattice relaxation time, 733±56 and 712±20 μs for the XeF_2 and Balz-Schiemann routes, several times the values reported for commercial HPHT nanodiamonds, although shorter than the 1173±123 μs of the as-received material. Fluorination thus activates near-surface NV^- centres, which dominate relaxometric sensing, at the cost of a moderate shortening of T_1.
ER -