Low sensitivity is the primary limitation to extending nuclear magnetic resonance (NMR) techniques to more advanced chemical and structural studies. Thanks to Photochemically induced dynamic nuclear polarization (photo-CIDNP) of a donor–acceptor chromophore molecule, we report the first example of optically enhanced solid-state 1H NMR spectroscopy in the high-field regime. These findings enable a new strategy for hyperpolarized NMR beyond the current limits of conventional microwave-driven DNP.
Low sensitivity is the primary limitation to extending nuclear magnetic resonance (NMR) techniques to more advanced chemical and structural studies. Photochemically induced dynamic nuclear polarization (photo-CIDNP) is an NMR hyperpolarization technique where light is used to excite a suitable donor–acceptor system, creating a spin-correlated radical pair whose evolution drives nuclear hyperpolarization. Here, we report the first example of optically enhanced solid-state 1H NMR spectroscopy in the high-field regime. This is achieved via photo-CIDNP of a donor–chromophore–acceptor molecule in a frozen solution at 0.3 T and 85 K, where spontaneous spin diffusion among the abundant strongly coupled 1H nuclei relays polarization through the whole sample, yielding a 16-fold bulk 1H signal enhancement under continuous laser irradiation at 450 nm. These findings enable a new strategy for hyperpolarized NMR beyond the current limits of conventional microwave-driven DNP.