Growth, thermal, dielectric and mechanical properties of L-phenylalanine-benzoic acid: a nonlinear optical single crystal.

An efficient amino acid family nonlinear optical single crystal L-phenylalanine-benzoic acid (LPB) was conveniently grown by slow evaporation technique at room temperature. The crystal system and the lattice parameters were analyzed by single crystal X-ray diffraction studies. The grown crystal has excellent transmission in the entire visible region and its lower cut-off wavelength was found to be 248 nm. The SHG efficiency of the grown crystal was found to be 1.6 times higher than that of KDP crystal. The Laser damage threshold value of LPB has been found to be 6.5 GW/cm(2). The sample was thermally stable up to 134°C. Microhardness, dielectric and AC/DC conductivity measurements were made along (001) plane and reported for the first time. Microhardness studies revealed that the sample belongs to hard nature. Frequency dependent dielectric constant was measured for different temperatures and found maximum dielectric constant of 14 for 363 K. Photoconductivity studies of LPB divulged its negative photoconducting nature.

Growth and physicochemical properties of L-phenylalaninium maleate: a novel nonlinear optical crystal.

Single crystals of novel organic nonlinear optical material, L-phenylalaninium maleate (LPM) having dimensions up to 10 × 6 × 6 mm(3) were grown by slow evaporation solution growth technique at room temperature. The grown crystals were confirmed by single crystal X-ray diffraction studies and the various functional groups were identified by FT-IR spectroscopic analysis. The optical properties were studied by optical absorption, second harmonic generation (SHG), photoconductivity and photoluminescence (PL) studies and reported for the first time. The optical band gap energy and SHG efficiency were found to be 4.85 eV and 1.5 times higher than KDP crystals. Negative photoconducting nature was confirmed by photoconductivity studies. Photoluminescence studies confirm the suitability of the sample for blue and green radiations. The title compound was also subjected to TG/DTA analysis and dielectric studies. Layer like growth pattern was analyzed by SEM micrograph.