Exploiting Endogenous Surface Defects for Dynamic Nuclear Polarization of Silicon Micro- and Nanoparticles

Abstract

Micro- and nanoparticles of elemental, crystalline silicon represent an attractive target for a wide range of applications spanning from quantum computing to contrast agents for biomedical imaging applications. To overcome the low sensitivity of the 29Si nuclei in magnetic resonance, dynamic nuclear polarization (DNP), which exploits the endogenous surface defects as a source of polarization, can be used to temporarily boost nuclear polarization of the 29Si spin bath. In the present work, we have assessed a number of commercially available silicon micro- and nanoparticles concerning properties and characteristics under DNP conditions. It has been found that optimal physical and chemical conditions, including surface-defect concentration adjusted to the particle size, are necessary to achieve a high level of polarization enhancement.