Radical-free dynamic nuclear polarization using electronic defects in silicon

Cassidy, Maja; Ramanathan, Chandrasekhar; Cory, David G.; Ager, Joel W.; Marcus, C. M.

doi:10.1103/physrevb.87.161306

Cited by 34 publications

(89 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The high enhancement factors, relatively long nuclear T 1 values, and rapid polarization buildups of the diamond samples just surveyed are akin to the properties of other kinds of radical‐containing nanoparticles that have been recently proposed as in vivo hyperpolarization tracers . Driven by these similarities, we investigated the potential use of diamond powders as hyperpolarized tracing agents in dissolution DNP NMR experiments.…”

Section: Resultssupporting

confidence: 57%

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution ¹³C NMR Spectroscopy

et al. 2016

View full text Add to dashboard Cite

Dynamic nuclear polarization (DNP) is a versatile option to improve the sensitivity of NMR and MRI. This versatility has elicited interest for overcoming potential limitations of these techniques, including the achievement of solid-state polarization enhancement at ambient conditions, and the maximization of (13) C signal lifetimes for performing in vivo MRI scans. This study explores whether diamond's (13) C behavior in nano- and micro-particles could be used to achieve these ends. The characteristics of diamond's DNP enhancement were analyzed for different magnetic fields, grain sizes, and sample environments ranging from cryogenic to ambient temperatures, in both solution and solid-state experiments. It was found that (13) C NMR signals could be boosted by orders of magnitude in either low- or room-temperature solid-state DNP experiments by utilizing naturally occurring paramagnetic P1 substitutional nitrogen defects. We attribute this behavior to the unusually long electronic/nuclear spin-lattice relaxation times characteristic of diamond, coupled with a time-independent cross-effect-like polarization transfer mechanism facilitated by a matching of the nitrogen-related hyperfine coupling and the (13) C Zeeman splitting. The efficiency of this solid-state polarization process, however, is harder to exploit in dissolution DNP-enhanced MRI contexts. The prospects for utilizing polarized diamond approaching nanoscale dimensions for both solid and solution applications are briefly discussed.

show abstract

Section: Resultssupporting

confidence: 57%

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution ¹³C NMR Spectroscopy

et al. 2016

View full text Add to dashboard Cite

show abstract

“…As Dreher et al have shown previously, EDMR can be used to detect protons adsorbed onto the silicon surface, analogous to NMR measured by way of NV centers [21]. This coupling between interfacial P b0 defects and surface nuclear spin species has also been observed in dynamic nuclear polarization experiments [45,46]. In principle, it should be possible to resonantly detect any spin system -electronic or nuclear -that is coupled to the interfacial defect spins.…”

Section: Discussionmentioning

confidence: 99%

Optical Dependence of Electrically Detected Magnetic Resonance in Lightly Doped Si:P Devices

et al. 2017

View full text Add to dashboard Cite

Electrically-detected magnetic resonance (EDMR) provides a highly sensitive method for reading out the state of donor spins in silicon. The technique relies on a spin-dependent recombination (SDR) process involving dopant spins that are coupled to interfacial defect spins near the Si/SiO2 interface. To prevent ionization of the donors, the experiments are performed at cryogenic temperatures and the mobile charge carriers needed are generated via optical excitation. The influence of this optical excitation on the SDR process and the resulting EDMR signal is still not well understood. Here, we use EDMR to characterize changes to both phosphorus and defect spin readout as a function of optical excitation using: a 980 nm laser with energy just above the silicon band edge at cryogenic temperatures; a 405 nm laser to generate hot surface-carriers; and a broadband white light source. EDMR signals are observed from the phosphorus donor and two distinct defect species in all the experiments. With near-infrared excitation, we find that the EDMR signal primarily arises from donor-defect pairs, while at higher photon energies there are significant additional contributions from defect-defect pairs. The optical penetration depth into silicon is also known to be strongly wavelength dependent at cryogenic temperatures. The energy of the optical excitation is observed to strongly modulate the kinetics of the SDR process. Careful tuning of the optical photon energy could therefore be used to control both the subset of spin pairs contributing to the EDMR signal as well as the dynamics of the SDR process.

show abstract

“…17,18,20,21,31,34,49 Trityl OX063, the stable organic radical used in this work, has a very narrow EPR linewidth that makes it ideal for polarizing low-γ nuclei such as 13 C. When using this free radical to polarize low-γ nuclei such as 13 C spins, DNP data at 3.35 T and temperatures close to 1 K have shown indications of thermal mixing (TM) as the predominant DNP mechanism. 24,[50][51][52][53] Other DNP data at similar conditions suggested that the mechanism could be a combination of the solid effect (SE) and cross effect (CE).…”

Section: Resultsmentioning

confidence: 99%

Influence of Dy3+ and Tb3+ doping on 13C dynamic nuclear polarization

Niedbalski

Parish

Kiswandhi

et al. 2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

Dynamic nuclear polarization (DNP) is a technique that uses a microwave-driven transfer of high spin alignment from electrons to nuclear spins. This is most effective at low temperature and high magnetic field, and with the invention of the dissolution method, the amplified nuclear magnetic resonance (NMR) signals in the frozen state in DNP can be harnessed in the liquid-state at physiologically acceptable temperature for in vitro and in vivo metabolic studies. A current optimization practice in dissolution DNP is to dope the sample with trace amounts of lanthanides such as Gd 3+ or Ho 3+ , which further improves the polarization. While Gd 3+ and Ho 3+ have been optimized for use in dissolution DNP, other lanthanides have not been exhaustively studied for use in 13 C DNP applications. In this work, two additional lanthanides with relatively high magnetic moments, Dy 3+ and Tb 3+ , were extensively optimized and tested as doping additives for 13 C DNP at 3.35 T and 1.2 K. We have found that both of these lanthanides are also beneficial additives, to a varying degree, for 13 C DNP. The optimal concentrations of Dy 3+ (1.5 mM) and Tb 3+ (0.25 mM) for 13 C DNP were found to be less than that of Gd 3+ (2 mM). W-band electron paramagnetic resonance shows that these enhancements due to Dy 3+ and Tb 3+ doping are accompanied by shortening of electron T 1 of trityl OX063 free radical. Furthermore, when dissolution was employed, Tb 3+ -doped samples were found to have similar liquid-state 13 C NMR signal enhancements compared to samples doped with Gd 3+ , and both Tb 3+ and Dy 3+ had a negligible liquid-state nuclear T 1 shortening effect which contrasts with the significant reduction in T 1 when using Gd 3+ . Our results show that Dy 3+ doping and Tb 3+ doping have a beneficial impact on 13 C DNP both in the solid and liquid states, and that Tb 3+ in particular could be used as a potential alternative to Gd 3+ in 13 C dissolution DNP experiments. Published by AIP Publishing.

show abstract

Radical-free dynamic nuclear polarization using electronic defects in silicon

Cited by 34 publications

References 42 publications

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution ¹³C NMR Spectroscopy

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution ¹³C NMR Spectroscopy

Optical Dependence of Electrically Detected Magnetic Resonance in Lightly Doped Si:P Devices

Influence of Dy3+ and Tb3+ doping on 13C dynamic nuclear polarization

Contact Info

Product

Resources

About

Radical-free dynamic nuclear polarization using electronic defects in silicon

Cited by 34 publications

References 42 publications

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution 13C NMR Spectroscopy

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution 13C NMR Spectroscopy

Optical Dependence of Electrically Detected Magnetic Resonance in Lightly Doped Si:P Devices

Influence of Dy3+ and Tb3+ doping on 13C dynamic nuclear polarization

Contact Info

Product

Resources

About

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution ¹³C NMR Spectroscopy

On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid‐State and Dissolution ¹³C NMR Spectroscopy