Crystal growth and characterisation of thiocyanate and thiourea ligands based transition metal zn hg cd mn complexes for nonlinear optical applications

Abstract

In the fast growing modern technology, the field of nonlinear optics newlinehas dominated the application area such as optical information processing newlinetelecommunications sensors optical phase conjugation image processing newlineoptical switching optical data processing and frequency generation newlineNonlinear optics field can explore extending its fruits with the help of good newlinequality single crystals Thus growing good quality crystals of highly efficient newlinematerials is a challenge that has been placed before the young researcher newlineMany semi organic materials combining metals with organic ligands have newlinebeen explored to be highly efficient nonlinear material newlineThe present thesis deals with the growth and characterisation of newlinesome metal organic complexes combining metals like Zn Cd Hg and Mn newlinewith some organic ligands like thiocyanate thiourea Nmethyl formamide newlineand thiosemicarbazide The thesis starts with a brief overview on the theory newlinebehind non linear optics the various types of nonlinear optical crystals newlinevarious crystal growth techniques and the fundamentals of various newlinecharacterisation techniques used to study the properties of the grown crystals newlineA detailed investigation on the growth and characterisation of newlinetetrathiourea mercury tetra thiocyanato manganate TMTM single crystal has newlinebeen discussed in the second chapter TMTM was grown by solvent newlineevaporation method The complex was found to crystallise in tetragonal newlinegeometry with the non centrosymmetric space group I4 The grown single newlinecrystal of TMTM shows 69 transparency over the entire range of visible newlineregion with a cutoff wavelength of 362 nm The SHG efficiency of TMTM newlinewas found to be 10 times that of KDP crystal The complex exhibits good newlinethermal stability up to 205 C Etching studies showed a layer growth pattern newlineThe thermal and mechanical properties of the TMTM are also presented Chapter 3 deals with the growth and characterisation of newlinetetrathiourea cadmium tetrathiocyanato zincate TCTZ The single crystal of newlinethe complex was grown using solvent evaporation method using 3 1 wateracetone newlinesolvent