A team in Japan experimentally shows that charge transport in an organic semiconductor can be tuned by varying the temperature and pressure. Charge transport in organic semiconductors has been much debated, with incompatible theories invoking either localized charge carriers hopping from molecule to molecule (incoherent transport) or delocalized charge carriers moving freely among the molecules (coherent transport) being put forward. Jun Takeya and colleagues at the University of Tokyo and the University of Tsukuba have realized a continuous change from one transport mechanism to the other in the aromatic hydrocarbon pentacene. They found that the transport mechanism depends on the degree to which the orbitals of neighbouring molecules overlap, which is sensitive to thermal fluctuations. Pushing molecules closer together through raising the pressure and lowering the temperature enhanced electronic coupling, boosting pentacene's mobility by 75 per cent.
展开▼
