An organic thin film transistor, and a method of making the same, comprising a source and drain electrode and organic semi-conductive material disposed therebetween in a channel region, in which the source and drain electrodes have disposed on them a thin self-assembled layer of a material comprising a dopant moiety for chemically doping the organic semi-conductive material by accepting electrons, the dopant moiety having a redox potential of at least 0.3 eV relative to a saturated calomel electrode in acetonitrile.