Synthesis, structural, optical, thermal, electrical, nonlinear optical and theoretical investigation on 3-aminopyridine picrate (3APP) single crystal

Abstract

A single crystal of 3-Aminopyridinium picrate (3APP), an organic nonlinear optical (NLO) crystal is successfully grown using a slow evaporation technique with a dimension of 18 × 4 × 3 mm3. Single crystal XRD measurement confirms that 3APP crystal belongs to the monoclinic crystal system with space group P21/n. Powder XRD analysis is performed to estimate the phase purities and crystalline perfection of the grown 3APP crystal. UV-Vis-DRS spectral analysis of the grown 3APP crystal shows 97% of transmittance and cut-off wavelength at 511 nm with an optical band gap (Eg) of 2.31 eV. The presence of various functional groups of 3APP crystal is identified qualitatively by FTIR study. The etching study is performed on the grown 3APP crystal in order to identify surface morphology and dislocation density. The elemental composition of the 3APP crystal is confirmed by using EDS analysis. Thermal studies indicate that the 3APP crystal is stable up to 198 °C. The high LDT of 10.56 against an Nd: YAG laser shows the suitability of the 3APP crystal for high-power laser device applications. Dielectric measurements are carried out to examine the dielectric properties and electronic polarizability values of the 3APP crystal. Third order NLO parameters of the 3APP crystal obtained by Z-scan techniques are n2 = 3.53 × 10−12 m2/W, β = 1.25 × 10−5 m/W and χ(3) 3.90 × 10−9 esu (5.46 × 10−17(m/V)2). Here β and n2 are positive, due to the two-photon absorption nature and self-focusing nature as detected in closed and open aperture z-scan spectra. Theoretical calculations are performed using density functional theory with B3LYP/6-311++G(d,p) level and related to experimental results. Furthermore, the Frontier FMO, MEP and NBO have been visualized and studied. The results suggested that the 3APP crystal is suitable for NLO, optoelectronic, optical switching and optical limiting applications.