Band gap enhancement on metal chelation: Growth and characterization of cobalt chelated glycine single crystals for optoelectronic applications

Single crystals of Diaqua Bisglycine Cobaltous Chloride (DBGCoCl) have been synthesized and grown by slow evaporation method. Grown crystals were subjected to FTIR and XRD studies for structural confirmation. The DBGCoCl crystallizes in the monoclinic system with the space group P21/c. The UV–vis spectrum for the pure glycine as well the cobalt chelated glycine have been recorded. The lower cutoff wavelength observed from the UV–vis spectrum is found to decrease by the chelation of cobalt with glycine and this leads to an increase in the band gap of the compound from 3.13 eV to 4.91 eV. The optical constants were calculated and illustrated graphically. Mechanical hardness of the grown crystal DBGCoCl was studied and Vickers hardness number was calculated. The work hardening coefficient (n) was determined to be 1.365 and the stiffness constants for different loads were calculated and reported. The thermal stability of the grown crystal has been studied using TGA and DTA. The crystal is thermally stable up to 116.86 °C.