An investigation on optical, mechanical and thermal properties of nickel sulphate hexahydrate single crystal-a UV band pass filter

Nickel sulphate hexahydrate (NSH) crystal is known to be an excellent material for UV light band-pass filter applications. In this research work, good quality and enhanced size of NSH single crystal has been effectively grown by implementing Sankaranarayanan-Ramasamy (SR) method. After a prolonged period of 185 days, a fine quality of transparent as well as improved size single crystal of NSH with dimension 220 mm in length and 12 mm in diameter has been successfully harvested. The grown crystal has been subjected to various characterizations as that of single crystal x-ray analysis to confirm the crystal system with unit cell parameters, UV-Vis analysis to know the transmission spectrum, FTIR spectral analysis to find out the functional groups and photoluminescence study to affirm the green emission of the crystal. NSH crystal falls into the category of soft material as identified by microhardness study and etching study confirms that it has good quality as the surfaces are almost free of defects. Photoacoustic spectroscopy has been utilized to find the thermophysical parameters. The resultant value of thermal diffusivity is compared with few other familiar nonlinear optical materials such that it is asserted by the observed superior value of NSH single crystal that it is an added advantage for band-pass filter and harmonic generation applications.