Electron-decoupled MAS DNP with N@C 60 .

Frequency-chirped microwaves decouple electron- and C-spins in magic-angle spinning N@C:C powder, improving DNP-enhanced C NMR signal intensity by 12% for 7 s polarization, and 5% for 30 s polarization. This electron decoupling demonstration is a step toward utilizing N@C as a controllable electron-spin source for magic-angle spinning magnetic resonance experiments.