High field dynamic nuclear polarization at 6.7Â T: Carbon-13 polarization above 70% within 20Â min

► Dynamic Nuclear Polarization (DNP) is performed at 1.2 K and 6.7 T with the free radical TEMPO. ► DNP is coupled to cross polarization (CP) to transfer protons magnetization to carbon-13. ► Carbon-13 polarization as high as 71% is attained in a record time.