Dynamic nuclear polarization: State of the art and future possibilities with light activation

Dynamic nuclear polarization (DNP) has emerged as a transformative technique for enhancing the sensitivity of nuclear magnetic resonance (NMR) signals, playing a crucial role in solid-state NMR spectroscopy and imaging applications. This review outlines the fundamental principles of DNP and its applications across various materials, which have yielded remarkable insights and advancements in the field. However, the employment of stable paramagnetic centers in traditional DNP introduces several challenges, such as paramagnetic relaxation, the spin diffusion barrier effect, and the requirement for low temperatures. Light-activated DNP is an approach that generates transient electron spins or highly polarized electron spins via optical pumping. This method has the potential to address several fundamental limitations of traditional DNP techniques. It offers enhanced hyperpolarization efficiency and reduced paramagnetic broadening, with the added possibility of functioning at room temperature. The review examines significant progress in light-activated DNP over recent years, emphasizing its potential to transform nuclear spin sensing techniques.