A switchable electronic device comprises a hole blocking layer and a layer comprising a conductive material between first and second electrodes, wherein the conductivity of the device may be irreversibly switched upon application of a current having a current density of less than or equal to 100 A cm−2 to a conductivity at least 100 times lower than the conductivity of the device before switching. The conductive material is a doped organic material such as doped optionally substituted poly(ethylene dioxythiophene).