Investigations on optical studies of organic single crystals grown by vertical bridgman technique

Abstract

This thesis presents the growth of organic single crystals using vertical Bridgman technique and various characterizations of grown crystals for technological applications. The first chapter describes about the need of single crystals and different growth methods to grow single crystals with its advantages and disadvantages. Particularly the importance of Bridgman method and various techniques involved in this method to grow good quality crystals are described in detail. Various ampoule shapes to grow single crystals are presented in this chapter. The theoretical background of nonlinear optics, the importance of growing organic NLO materials and its advantages are discussed. Also a review of organic single crystals grown from melts in recent years is also presented. The working principle, mode of operation, advantages and limitations of various characterizations techniques involved in this work are discussed.Second chapter discusses about the growth of 4,4 and#1523;-dimethoxybenzoin single crystal by vertical Bridgman technique and different characterization studies of grown crystal. The construction of Bridgman furnace and optimized temperature profile of the furnace to grow crystals are presented. The translation assembly and suitable range of growth rate for various materials including organic crystals are briefly described. The orthorhombic crystal structure with space group P212121 was confirmed by single crystal X-ray diffraction (XRD) measurements. The peaks from powder X-ray diffraction (XRD) pattern also confirm the structure. The presence of functional groups in the compound was identified with Fourier Transform Infrared (FTIR) studies. newline