Völker Laura A, Herb Konstantin, Merchant Darin A, Bechelli Lorenzo, Degen Christian L, Abendroth John M
Department of Physics, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland.
Quantum Center, ETH Zürich, 8093 Zürich, Switzerland.
Nano Lett. 2024 Sep 25;24(38):11895-11903. doi: 10.1021/acs.nanolett.4c03064. Epub 2024 Sep 12.
Shallow nitrogen-vacancy (NV) centers in diamond offer opportunities to study photochemical reactions, including photogeneration of radical pairs, at the single-molecule regime. A prerequisite is a detailed understanding of charge and spin dynamics of NVs exposed to the short-wavelength light required to excite chemical species. Here, we investigate the charge and spin dynamics of shallow NVs under 445 and 375 nm illumination. With blue excitation, charge-state preparation is power-dependent, and modest spin initialization fidelity is observed. Under UV excitation, charge-state preparation is power-independent and no spin polarization is observed. Aging of NVs under prolonged UV exposure manifests in a reduced charge stability and spin contrast. We attribute this aging to modified local charge environments of near-surface NVs and identify distinct electronic traps only accessible at short wavelengths. Finally, we evaluate the prospects of NVs to probe photogenerated radical pairs based on measured sensitivities and outline possible sensing schemes.
金刚石中的浅氮空位（NV）中心为在单分子水平上研究光化学反应（包括自由基对的光生）提供了机会。一个先决条件是详细了解暴露于激发化学物种所需的短波长光下的NV的电荷和自旋动力学。在这里，我们研究了在445和375nm光照下浅NV的电荷和自旋动力学。在蓝光激发下，电荷态制备与功率有关，并观察到适度的自旋初始化保真度。在紫外光激发下，电荷态制备与功率无关，且未观察到自旋极化。长时间紫外光照射下NV的老化表现为电荷稳定性和自旋对比度降低。我们将这种老化归因于近表面NV的局部电荷环境的改变，并识别出仅在短波长下可及的不同电子陷阱。最后，我们根据测量的灵敏度评估NV探测光生自由基对的前景，并概述可能的传感方案。
