Publication Date
12-20-2023
Document Type
Article
Publication Title
ACS Nanoscience Au
Volume
3
Issue
6
DOI
10.1021/acsnanoscienceau.3c00033
First Page
462
Last Page
474
Abstract
Surface chemistry of materials that host quantum bits such as diamond is an important avenue of exploration as quantum computation and quantum sensing platforms mature. Interfacing diamond in general and nanoscale diamond (ND) in particular with silica is a potential route to integrate room temperature quantum bits into photonic devices, fiber optics, cells, or tissues with flexible functionalization chemistry. While silica growth on ND cores has been used successfully for quantum sensing and biolabeling, the surface mechanism to initiate growth was unknown. This report describes the surface chemistry responsible for silica bond formation on diamond and uses X-ray absorption spectroscopy (XAS) to probe the diamond surface chemistry and its electronic structure with increasing silica thickness. A modified Stöber (Cigler) method was used to synthesize 2-35 nm thick shells of SiO2 onto carboxylic acid-rich ND cores. The diamond morphology, surface, and electronic structure were characterized by overlapping techniques including electron microscopy. Importantly, we discovered that SiO2 growth on carboxylated NDs eliminates the presence of carboxylic acids and that basic ethanolic solutions convert the ND surface to an alcohol-rich surface prior to silica growth. The data supports a mechanism that alcohols on the ND surface generate silyl-ether (ND-O-Si-(OH)3) bonds due to rehydroxylation by ammonium hydroxide in ethanol. The suppression of the diamond electronic structure as a function of SiO2 thickness was observed for the first time, and a maximum probing depth of ∼14 nm was calculated. XAS spectra based on the Auger electron escape depth was modeled using the NIST database for the Simulation of Electron Spectra for Surface Analysis (SESSA) to support our experimental results. Additionally, resonant inelastic X-ray scattering (RIXS) maps produced by the transition edge sensor reinforces the chemical analysis provided by XAS. Researchers using diamond or high-pressure high temperature (HPHT) NDs and other exotic materials (e.g., silicon carbide or cubic-boron nitride) for quantum sensing applications may exploit these results to design new layered or core-shell quantum sensors by forming covalent bonds via surface alcohol groups.
Funding Number
1SC3GM125574-01
Funding Sponsor
National Science Foundation
Keywords
core−shell nanoparticles, diamond, nitrogen vacancy centers, silica, X-ray absorption spectroscopy
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Department
Chemistry
Recommended Citation
Perla J. Sandoval, Karen Lopez, Andres Arreola, Anida Len, Nedah Basravi, Pomaikaimaikalani Yamaguchi, Rina Kawamura, Camron X. Stokes, Cynthia Melendrez, Davida Simpson, Sang Jun Lee, Charles James Titus, Virginia Altoe, Sami Sainio, Dennis Nordlund, Kent Irwin, and Abraham Wolcott. "Quantum Diamonds at the Beach: Chemical Insights into Silica Growth on Nanoscale Diamond using Multimodal Characterization and Simulation" ACS Nanoscience Au (2023): 462-474. https://doi.org/10.1021/acsnanoscienceau.3c00033
