Studies on the effect of L-alanine on the structural, optical and thermal properties of potassium acid phthalate crystals

Potassium acid phthalate (KAP) crystals are promising materials as good monochromator for the qualitative and quantitative X-ray analysis of light elements like Fe, Al, Mg, F, Si, etc. in a long and middle range. KAP crystal exhibits a rare blend of ionic and molecular properties and has wide application by virtue of their polar nature. KAP is a non cenrrosymmerric molecular ionic crystal. L-alanine is an efficient organic non Linear Optical (NLO) compound under the amino acid group. L-alanine doped semi organic material like KAP may be the fundamental building block to develop many complex crystals with improved NLO properties. In this paper an attempt has been made to grow large size optically transparent L-alanine doped KAP crystals by slow evaporation solution growth technique and to see the effects of L-alanine into the pure KAP crystals. The chemical composition of the grown crystals was determined by Energy Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) Spectroscopy. The structure of pure and L-alanine doped KAP crystals have been examined by powder X-ray diffraction (XRD) study. Optical properties of the grown crystals were studied using UV-visible specrtroscopy. Using Thermogravimetry (TG) and Differential Thermal Analysis (DTA), the decomposition temperature was obtained. Powder XRD study on grown crystals showed that they belong to an orthorhombic system. The transmission in the visible region and the thermal stability of the crystal was found to increase with the doping concentration of L-alanine into the KAP crystal. Optically transparent, large size and thermally stable L-alanine doped KAP crystals were grown successfully in a laboratory for useful application in opto-electromc devices. © 2011 Asian Network for Scientific nformation.