Investigations on the synthesis growth and characterisation of cyclohexanone derivative crystals for optical applications

Abstract

Nonlinear optic (NLO) materials are playing a significant and an unavoidable role in the field of nonlinear optics and optoelectronics. The research in NLO materials are motivated by realization of these materials in optical device fabrication. Either large data to be stored or large data to be transmitted, NLO materials with, good nonlinear hyperpolarizability, good thermal stability and transparency in UV, visible and IR region are required. Different types of materials are tested for their optical nonlinearity. Among them, organic materials are more superior than inorganic materials. Since movement of delocalized electrons cause the optical nonlinearity, ultra fast switching could be achieved. Easy synthesis, existence of conjugation, molecular tailorability, availability of various donor and acceptor substituents, crystallizing in noncentrosymmetry space group and formation of hydrogen bondings are some of the advantages of organic material to be employed for nonlinear applications. Enhancement of hyperpolarizability could be done by understanding the structure-activity relationship. Various characterization techniques and interpretation of the results from these methods will help to develope a theoretical model, which in turn, will predict the physico-chemical characteristics. In that view, cyclohexanone derivatives, which are not studied earlier for their SHG, is taken and different characterizations have been done to understand the structure-activity relationships. Here seven crystals, among them one of it is polymorph, were synthesized by standard aldol condensation. Different solvents were used to grow crystals by slow evaporation method and various characterizations have been done to understand their ability for industrial applications. Here, either different electron donors and acceptors or different in their place in aromatic rings were used to investigate their SHG efficiency. This thesis consists of seven chapters. First chapter presents brief introduction about the importance of crystal growth