Functionalized Fluorescent Nanodiamonds with Millisecond Spin Relaxation Times.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41107207.
- Also identified by DOI 10.1021/acsnano.5c02407 and PMC identifier 12574219.
- Licence recorded as CC BY-NC-ND.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Fluorescent nanodiamonds (FNDs) containing nitrogen-vacancy (NV) defects are useful probes for biological imaging and nanoscale sensing applications. Here, we explore the effect of chemical surface modifications and core-shell structures on the <i>T</i><sub>1</sub> relaxation times of 100 nm FNDs hosting nitrogen-vacancy ensembles. The results show that surface oxidation and silica coating of FNDs using the Stöber method can dramatically increase the spin relaxation time from <i>T</i><sub><i>1</i></sub> = <i>320</i> ± 9 μs to <i>T</i><sub><i>1</i></sub> = 1.00 ± 0.06 ms. Using FT-IR and NEXAFS measurements conducted on air oxidized particles, we find that changes to surface functional groups and sp<sup>2</sup> carbon density may be responsible for the observed enhancements to the spin relaxation rate. Finally, we use a Monte Carlo model to numerically investigate the relationship between chemical sensitivity and shell thickness and find that a shell thickness on the order of 1 nm should provide the highest sensitivity. Our findings demonstrate that the surface of FNDs can be engineered to exhibit bulk-like <i>T</i><sub>1</sub> relaxation times, in the absence of complex quantum control sequences, which is crucial to advancing biosensing and imaging applications where surface spin noise currently limits measurement precision.