Organic electronics: the nuclear option

The conductivity of electronic materials is fundamentally determined by the interaction of its charge carriers with their environment. In devices based on conducting polymers, the dipole-mediated hyperfine interactions of polarons with the ubiquitous hydrogen nuclear spins are thought to be responsible for a range of phenomena including the extremely large magnetoresistive effects that are often seen.1 Malissa et al.2 have now demonstrated an elegant approach to investigating these effects in working devices by utilizing electron-nuclear double resonance and electron spin-echo envelope modulation, both detected by monitoring the change in the current through a poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)-based organic light-emitting diode (see Figure 1).