Insight into charge transportation in cadmium based semiconducting organic–inorganic hybrid materials and their application in the fabrication of photosensitive Schottky devices

Abstract

A coordination polymer (1) and a trinuclear complex (2) have been synthesized using a compartmental N₂O₂O₂′ donor Schiff base ligand. Both complexes are characterized using different spectroscopic techniques and their structures are determined using single crystal X-ray diffraction analyses. Energies associated with different non-covalent (S⋯O chalcogen bonds, C–H⋯H–C, C–H⋯I and C–H⋯π) interactions in the solid state of both complexes have been calculated using the Turbomole program. Investigations of electrical conductivity and photosensitivity of both complexes reveal that suitable Schottky diode devices could be fabricated from both complexes. The current vs. voltage plots of the complex based devices have been used to calculate the conductivity under dark and irradiation conditions. In both complexes the charge transportation mainly occurs through space which involves the hopping process. Standard band theory has been used to compare the experimental and theoretical results of optoelectronic measurements. The calculations confirm that both are direct band gap (2.78 and 3.30 eV) semiconductors and that complex 1 exhibits a lower band gap, in line with the experimental results (3.21 and 3.43 eV in 1 and 2, respectively).