Structural, morphological, opto-nonlinear-limiting studies on Dy:PbI ₂ /FTO thin films derived facilely by spin coating technique for optoelectronic technology

For cost-effective fabrication of pure and 0.2, 0.4, 0.6 and 0.8 wt% Dy doped PbI ₂ thin films on FTO substrate using spin coating process was developed. First, we synthesized the pure and different concentrations of Dy doped PbI ₂ by a facile microwave route (within 15 min) at 700W power. Single phase and highly oriented films were fabricated on FTO substrate was confirmed by X-ray diffraction analysis. Further, lattice constant, crystallite size, dislocation density, lattice strain, number of unit cells, texture coefficients etc. were evaluated. Lattice constants were observed in good agreement with JCPDS#7–0235. The values of crystallite size were found in the range of 14 nm–28 nm. Moreover, FT-Raman study also confirms the single phase and high crystallinity of the fabricated films. Surface morphology was analyzed by SEM, as nanorods shape and nanoparticles; and grains size was in the range of 25–40 nm. Robust optical, nonlinear and optical limiting studies were carried out to have deep insight on key properties of films for future device applications. The optical energy gap was found in the range of 2.35–2.65 eV. The values of χ ⁽¹⁾ , χ ⁽³⁾ and n ⁽²⁾ were found in the range of 0.35–1.4, 0.023 to 8.15 (× 10 ⁻¹⁰ ) esu and 0.0052 to 6.94 (× 10 ⁻⁹ ), respectively. The optical limiting values were found in the range of 10.5–7.7 mW (532 nm CW laser) and 208.2–134.5 μW (632.8 nm CW laser) for all deposited films.