Photosensitive field effect transistor based on metallo-phthalocyanines containing (4-pentylphenyl) ethynyl moieties

The syntheses of new cobalt, manganese and zinc phthalocyanine complexes containing 4-pentylphenylethynyl substituents at the peripheral positions are reported. 4-[(4-pentylphenyl) ethynyl] phthalonitrile was obtained through Sonogashira coupling reaction. The new compounds have been characterized using UV–vis, FT- IR, ¹H NMR, ¹³C NMR, and mass spectroscopy data. In order to study the dependence of device performance on the central metal atom, photosensitive field effect transistor based on tetra-substituted metallo phthalocyanines with [(4-pentylphenyl) ethynyl groups at peripheral positions were fabricated and characterized. Photoelectric characterization results showed that the device with active layer of 3 exhibits highest photoelectric performance with maximum field effect mobility (4.27 ×10^-3 cm²/Vs), photosensitivity (72.05), and photo/dark current ratio (230). It was found that the photoelectric performance of the Pc compounds depends on the central metal atom which is found consistent with UV–vis spectrum. Surface topography of the sensing films were analyzed by atomic force microscopy.