Computational and experimental investigation on piperazinediium bis (4-aminobenzoate) dihydrate single crystal for NLO applications

Abstract

Piperazinediium bis (4-aminobenzoate) dihydrate (P4AB) single crystal was grown successfully through slow evaporation. Several characterizations of the P4AB crystal were performed to understand its optical, dielectric, thermal, NLO, and structural properties. The structural information of the P4AB crystal was evaluated using single crystal x-ray diffraction (SXRD); P4AB material is an orthorhombic system with a centrosymmetric space group P21/c. The UV–vis–NIR study showed that the P4AB crystal had a large transmission window and exhibited a near-UV cut-off wavelength of 327 nm. The functional groups and their respective band assignments were revealed using Fourier transform infrared (FTIR) analysis. Thermal stability was ascertained through thermogravimetric and differential thermal analysis (TG-DTA). The ions of the incorporated acid compound significantly improved the dielectric, mechanical, and optical properties; they also improved the activation energy and conductivity of the P4AB crystal. In addition, they improved the energy band gap, optical transmittance, and second and third-order nonlinear optical efficiency. The open aperture z-scan technique was employed to investigate the sample's NLO absorption at 532 nm. Quantum chemical calculations were performed with B3LYP/6–311++G (d,p) level of basis set. The optimized geometry, HOMO-LUMO values, and first-order hyperpolarizability were assessed.