Cassidy, M.C., et al., Radical-free dynamic nuclear polarization using electronic defects in silicon. Physical Review B, 2013. 87(16): p. 161306.
http://link.aps.org/doi/10.1103/PhysRevB.87.161306
Direct dynamic nuclear polarization of 1H nuclei in frozen water and water-ethanol mixtures is demonstrated using silicon nanoparticles as the polarizing agent. Electron spins at dangling-bond sites near the silicon surface are identified as the source of the nuclear hyperpolarization. This polarization method opens avenues for the fabrication of surface engineered nanostructures to create high nuclear spin polarized solutions without introducing contaminating radicals, and for the study of molecules adsorbed onto surfaces.