Investigation on structural, elemental, thermal, mechanical, linear, and nonlinear optical nature of potassium pentaborate tetrahydrate inorganic single crystals

Potassium pentaborate tetrahydrate (PPBTH) is an inorganic nonlinear optical single crystal. It was grown by slow evaporation solution growth method at room temperature and physical properties there are studied. The lattice parameters of grown crystal were determined using single-crystal and powder X-ray diffraction analysis. The functional group of various vibrational modes was assigned using FTIR spectrum. The optical transmittance, optical band gap, optical constants, and extinction coefficient were determined by recording UV–Vis–NIR spectrum. The fluorescence study confirmed the green emission of PPBTH. Vickers hardness test estimates the mechanical properties for various loads. This material exhibited the soft material category. The magnetic properties of PPBTH were studied by vibrating sample magnetometer. Thermal behaviours of the grown crystals have been investigated using TGA/DTA analysis. The nonlinear optical studies confirm the second harmonic generation signal of the grown sample.