An investigation on structural, optical and enhanced third order nonlinear optical properties of facilely synthesized Ce:CuS nanosheets

Current work reported facile chemical synthesis of hexagonal covellite CuS nanostructures with 0.0, 1.0, 3.0 and 5.0 wt% cerium doping concentrations. Scherrer's equation used to determine the crystallites size and preferred orientation of growth plane is found along (1 1 0). Raman spectra of CuS nanostructures showed the characteristics sharp peak at the ∼ 472.21 cm⁻¹. SEM images revealed the shape of nanostructures as nanosheets (NSs) for Ce:CuS. The band gap values of Ce:CuS NSs was computed from diffuse reflectance spectra (DRS) using Kubelka-Munk (K-M) theory which was found in range of 1.56–1.85 eV. Red and UV emission band of nanostructures can be seen in Photoluminescence spectra clearly. Third order nonlinear optics were performed by Z-scan techniques via femtosecond fiber pulsed laser. The nonlinear absorption coefficients (β) and nonlinear refractive index (n₂) were found in range of 1.14 × 10^-8–2.04 × 10^-8 cm/W and 1.04 × 10^-12–1.38 × 10^-12 cm²/W, respectively. The value of third order nonlinear optical susceptibility (χ⁽³⁾) was noticed ∼ 3.36 × 10^-8–5.48 × 10^-8 esu. A significant improvement was observed in χ⁽³⁾ with Ce incorporation in CuS lattice system. Therefore, Ce doping makes CuS potential nonlinear optical material for modern photonics device applications.