Investigation on the optical, electronic, and thermal parameters of ammonium pentaborate tetrahydrate single crystal for photonic application

Ammonium pentaborate tetrahydrate (APBTH), an efficient inorganic crystal was grown up using slow evaporation process. APBTH was analyzed by single-crystal XRD confirm the structure (monoclinic) cell parameters with space group P_n. The luminescence nature of APBTH has been accomplished by the analysis of PL which affirmed violet and green emission spectrum. The UV spectra reveal good transmittance value in the visible spectrum showing lower cut-off wavelength at 252 nm and the band gap value is 5.61 eV. The thermal analysis discloses that the grown crystal possesses the thermal stability of about 110 °C. The dielectric feature was determined and Jonscher law affirms the conductivity process with s = 0.984. The laser damage threshold was calculated from LDT analysis to evaluate the suitability of the material for high power laser applications. SHG efficiency was affirmed by Kurtz–Perry method. The third-order nonlinearity of APBTH was analyzed and its value are given as 3.524 × 10^–10 cm² W⁻¹ (n₂), 0.0157 × 10⁻⁴ cm² W⁻¹ (β), 3.487 × 10^–8 esu (χ³) substantiates its application in nonlinear optical process.