Nuclear spin polarization transfer across an organic-semiconductor interface

Motivated by Tycko’s proposal to harness optically pumped nuclear spin polarization for the enhancement of nuclear magnetic resonance ~NMR! signals from biological macromolecules, we investigate the transfer of thermal nuclear spin polarization between H or F in an organic overlayer and P at the surface of micron-sized InP particles by Hartmann–Hahn cross polarization. Comparison with analytic and numerical models indicates that the total quantity of polarization transferred across the semiconductor-organic interface is limited by the relatively short room-temperature H T1r ~11 ms! and the slow diffusion of nuclear spin polarization in the semiconductor. Models and spin-counting experiments indicate that we are able to transfer approximately 20% of the total nuclear spin polarization originating in the organic overlayer to the semiconductor, supporting the feasibility of transferred optically pumped NMR. © 2003 American Institute of Physics. @DOI: 10.1063/1.1617975#