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内容記述 |
2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) is known as a molecule with a stable radical so is widely used as a spin label or radical scavenger in ESR measurements. The conventional ESR measurements require a comparatively large amount of sample so is performed at a comparatively low spatial resolution. However, bio-application such as cellular metabolism analyses often requires a spatial resolution at subcellular levels. The nitrogen vacancy centers (NV centers) in diamond makes it possible to detect the change in the spin states of a small number of TEMPO molecules [1] with high spatial resolution. Furthermore, TEMPO radicals work as a quantum reporter that transfers the nuclear spin states of neighbor molecules on the diamond surface to NV center electron spins [2]. Therefore, the combination of NV centers and TEMPO molecules has potential to perform ESR measurements with ultrahigh spatial resolution. The issue in the novel ESR measurements with NV centers is that diamond intrinsically has surface dangling bonds and substitutional nitrogen atoms (P1 centers) which are difficult to distinguish from TEMPO radicals. This is because all the magnetic dipole-dipole interactions have similar g-values. In this study, we report the possibility of overcoming this issue by preparing a system with and without TEMPO adsorbed on the diamond surface and a system with and without P1 centers around NV centers. Then, we investigated a method to distinguish signal from TEMPO molecules from that from P1 centers by using the systems with single/ensemble NV centers. |
