Modification in structural, functional, thermal, dielectric, impedance and nonlinear optical properties of ammonium pentaborate crystal by addition of di-sodium sulphide nanoparticles

Abstract

Ammonium penataborate (APB) crystals are well known for their nonlinear optical (NLO) properties. Attempt is made to study the changes produced by addition of chalcogenide compound sodium sulphide in APB crystals. Di-sodium sulphide (Na2S) is soluble in water and its solubility is further increased for Na2S nanoparticles. The Na2S nanoparticles are synthesized by using co-precipitation method followed by microwave irradiation. The slow solvent evaporation method is used to grow pure and Na2S added APB crystals. Pure and Na2S added APB crystals possess orthorhombic crystal structure with the mixed phase nature for the Na2S added APB. The presence of sodium in APB is confirmed by AAS study. In FTIR spectra the absorption peak of S–H asymmetric stretching is observed for Na2S added APB indicating the presence of sulphur. The thermal stability of APB crystal is enhanced on doping the Na2S in it. The dielectric study is also carried out within this frequency range. The Jonscher’s power law is applied to AC conductivity data. The impedance spectroscopy study is carried out at room temperature within 100 Hz to 1 MHz frequency range. The complex impedance and modulus plots are drawn. The complex impedance plots indicate only the grain contribution. The Kurtz and Perry powder study indicates that all the crystals are exhibiting NLO properties with varying SHG efficiency.