Photoconductivity of Copper Phthalocyanine Single Crystals

Abstract

Dark conductivity and photoconductivity of copper Phthalocyanine single crystals of the β form are measured as a function of electric field strength, temperature and light intensity in vacuum and in the atmosphere of H ₂ , O ₂ and Ar. The spectral responces of photocurrent and optical absorption are also measured in the atmosphere of H ₂ . The conductivity of a copper phthalocyanine single crystal is 1×10 ^-11 Ω ^-1 cm ^-1 at 100°C and the activation energy of dark current is 1.96±0.05 eV in the measured range of 30°C to 250°C, while that of photocurrent is 0.41±0.03 eV in the measured range from 30°C to 200°C. The photocurrent generated by continuous illumination depends on the square root of light intensity and that generated by flash illumination of Q switched ruby laser light decays via bimolecular recombination. The photocurrent per quantum of incident light appears to vary with wave length in the same way as the absorption coefficient. These results are consistent with the scheme that photocarriers are generated via exciton surface interaction and decay via bimolecular recombination.