Growth, Structural, Third Order Nonlinear Optical Properties, Dielectric Properties, Conductivity Mechanisms and Spectroscopic Characterization of a Luminescent Material Trans-Diaqua-bis(pyridine-2-carboxylato)-cobalt(ii) Dihydrate for Optoelectronic Applications

Single crystals of trans-diaqua-bis(pyridine-2-carboxylato)-cobalt(ii) dihydrate (PCOH) have been successfully grown by slow evaporation technique. The formation of crystalline structure and cell parameters were confirmed by single crystal and powder X-ray diffraction techniques respectively. The structural and optical characterization of the PCOH were analyzed experimentally by FT-IR, FT-Raman and UV-visible spectroscopic technique and theoretical studies by density functional theory method. The charge transfer interactions leading to nonlinear properties taking place in the molecule can be studied by HOMO-LUMO analysis and natural bond orbital analysis. DFT computations using CAM-B3LYP/GenECP and B3LYP/GenECP were performed to determine the linear as well as NLO properties. Open aperture Z-Scan results confirm the competence of these materials as optical limiters (NLO). Furthermore, the PCOH exhibits a blue luminescence emission, as can be seen from the (CIE) chromaticity diagram, and hence the complex may be a promising blue organic light-emitting diode (OLED) in the development of electroluminescent materials for flat-panel-display applications. The electrical properties such as dielectric constant, dielectric loss and ac conductivity of the sample were carried out at different temperatures. The Cole-Cole plot shows the presence of grain and grain boundary, it is found that single relaxation is observed in the crystal. These attractive luminescence emission and third-order nonlinear results indicated that PCOH appear to be promising candidates for optoelectronic applications.