Facile fabrication of novel nanostructured Au@PbI2 thin films and their structure, optical and NLO studies for higher order nonlinear applications

Abstract

Herein, a facile fabrication of gold (Au) doped lead iodide (PbI2) (Au@PbI2) thin films have been achieved via spin-coating process from the microwave-synthesized Au@PbI2 nanosheets for the first time. Phase was confirmed from X-ray diffraction and FT-Raman spectroscopy analyses and approved 2H-Polytype of PbI2. The grain sizes were estimated via atomic force microscopy (AFM) and noticed between 13.5 and 9.2 nm for PbI2 and Au@PbI2 sample respectively. The Au doping in PbI2 was seen in EDX spectra and its homogeneity in SEM e-mapping. The nanostructured films fabrication was confirmed by SEM/AFM images. The transmittance of grown films is quite good in the visible region and reduction was seen in Au@PbI2 film compare to pristine. The energy gaps were estimated ~2.41 eV for pure and 2.45 eV for Au@PbI2 films. The value of refractive index was noticed ~2 in lower wavelength region. Dielectric constant and loss values were also determined. The highest values of nonlinear parameters like χ1, χ1 and n2 are found to be 0.68, 3.5 × 10−11 (esu) and 4.3 × 10−10 (esu) respectively at 1.11 eV of energy.