Abstract
Organic-inorganic hybrids based on liquid crystalline symmetrical imine (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine (AZJ1) with two aliphatic chains and TiO₂ nanomaterials were obtained and investigated taking into account thr crystallographic form of titanium dioxide i.e., anatase versus rutile. The type of TiO₂ influences the mesomorphic properties of imine AZJ1, as observed by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques. Fourier-Transform Infrared Spectroscopy (FT-IR) was used to investigate the interactions of oxygen vacancies located on the TiO₂ surface with the studied AZJ1 imine together with studying the influence of temperature. Both imine:TiO₂ anatase versus rutile hybrids possessed the highest occupied molecular orbital (HOMO) levels of about -5.39 eV (AZJ1:anatase) and -5.33 eV (AZJ1:rutile) and the lowest unoccupied molecular orbital (LUMO) levels of about -2.24 eV. The presence of TiO₂ in each hybrid did not strongly affect the redox properties of imine AZJ1. Organic devices with the configuration of ITO/TiO₂/AZJ1 (or AZJ1:TiO₂ anatase versus rutile)/Au were fabricated and investigated in the presence and absence of visible light irradiation with a light intensity of 93 mW/cm². Finally, to analyze defects in the constructed organic devices we used thermal imaging and atomic force microscopy (AFM). The addition of TiO₂ in both crystallographic forms has a positive influence on layer-forming properties that manifests itself as a very homogenous heat distribution for the whole sample.