The enhancement of dark d.c. conductivity by gas adsorption on thin films of macrocyclic copper complexes

The dark d.c. conductance of thin films of copper complexes of phthalocyanine (α-form), hemiporphyrazine and dihydrodibenzo b, i] 1, 4, 8, 11] tetra-azacyclotetradecine has been studied in vacuo and in the presence of an extensive range of gases. Only those gases which can be classed as electron acceptors increased the conductance, with NO₂/N₂O₄ (“NOX”) being particularly effective. Spectroscopic evidence is provided to show that the NOX-copper phthalocyanine interaction generates the organic radical cation and NO^-₂, and that substantial quantities of gas are accumulated within the thin film. A new class of extrinsic organic semiconductor is described.