Structural, optical, spectroscopic and thermal investigations on novel semi-organic nonlinear optical material - Potassium boro-oxalate single crystal

Abstract

In this work, a new semi-organic nonlinear optical material of Potassium boro-oxalate (KBO) is synthesized and subsequently a single crystal of size 7 × 5 × 3 mm3 is grown from the aqueous solution by slow evaporation technique at ambient temperature. Characterizations are performed on the single crystals to study the structural, thermal, linear and nonlinear optical (NLO) properties of the as-grown single crystals. Crystal and molecular structure of KBO are solved by direct method and further refinement is performed by full-matrix least-square method employing SHELXL-2014 software. Single crystal X-ray diffraction (SXRD) studies revealed that the grown crystal associates to triclinic crystal family with non-centrosymmetric space group P1. The Fourier transform infrared (FTIR) spectrum reflected the presence of various functional groups in the title compound. The Ultraviolet-visible-near infrared (UV-VIS-NIR) absorption and transmission spectrum are recorded to capture the suitability of the grown single crystals for various optical and NLO applications. The thermal decomposition and thermal stability of the KBO single crystals up to 187°C are investigated by TGA-DTG (Thermo Gravimetric - Differential Thermo Gravimetric), TGA-DTA (Thermo Gravimetric-Differential Thermal analysis) and DSC (Differential Scanning Calorimetry) curves. Kurtz-Perry powder technique is employed to explore the SHG (Second Harmonic Generation) efficiency of the KBO single crystals. SHG efficiency of KBO is found to be comparable to KDP.