Crystal growth, optical, physico-chemical and third-order nonlinear optical studies of morpholinium oxalate: a new organic single crystal for optical limiting application

A single crystal of morpholinium oxalate (MO) was grown by the technique of slow evaporation at ambient temperature utilizing water as a solvent. Single crystal XRD reveals the MO crystal belongs to the monoclinic system with a centrosymmetric space group of P2₁/n. Powder XRD study demonstrates the crystalline quality. HRXRD study illustrates the crystalline perfection of the crystal and it is the key necessity for device fabrication. The optical transmittance (55%), cut-off wavelength (λ = 330 nm) and band gap energy (E_g = 2.61 eV) were determined by optical studies. Laser-induced surface damage threshold (LDT) analysis appraises the aptness of grown crystal for device fabrications and also the surface roughness of the sample was determined. The thermal stability and decomposition of the crystal were studied by thermogravimetric (TG) analysis and it was found that the material was thermally stable up to 179 °C. The various thermodynamical parameters were determined from TG analysis. The dielectric constant ɛ^' and dielectric loss ɛ^'' divulges the electrical properties of MO crystal and the various electronic parameters were also calculated. The nonlinear optical (NLO) behavior and optical limiting property were analyzed from Z-scan technique. Microhardness measurement was executed to recognize the mechanical strength of the MO crystal and its hardness value is 1.65 kg/mm². Graphical abstract:

.