Tailoring the optical characteristics and band-gap of BG doped PMMA/FTO nanocomposite films for laser power attenuation: New approach

Herein a good adherent film of PMMA doped with the various ratio of BG-dye deposited on optically flat FTOsubstrates by using a well-controlled spin coating process. The average crystallite size and microstrain were determined by X-ray diffraction pattern analysis and were found to be 21.7219 nm and 0.0016, respectively, with a significant change with the amount of BG-dye doping in the matrix of PMMA film. Both linear and nonlinear optical characteristics, as well as their related parameters, were measured using a UV-Vis-NIR spectrophotometer. As a result of doping BG-dye molecules into the host PMMA matrix system, optical absorption studies revealed significant changes in optical characteristics. BG-dye doped PMMA film revealed impressive absorption bands in the range of 350-750 nm, depending on the degree of doping of BG-dye into the PMMA film. Another distinguished property is the attenuation of the complete absorption in the range of 552-688 nm and observed as a cut-off-absorbance. The point of the art of this contribution is the various applications for optical limitation systems like Cut-off filters and other related optical devices due to the remarkable optical features. The BG-dye doping influenced all optical metrics, including the absorption band, absorption edge, and direct and/or indirect energy band gap. The direct energy gap's first region is in the range of 1.77-1.97 eV, whereas the second is in the range of 2.68-2.82 eV, and the third is in the range of 3.67-4.09 eV. The indirectly allowed transitions are divided into two regions, the first of which is in the 1.74-1.82 eV range and the second of which is in the 3.69-3.98 eV range. The appearance of extra energy levels is confirmed by fluctuations in the optical band gap, which are aided by the influence of dopant concentration of BG-dye dopant wt.%. The ratio of BG-dye into the PMMA film is promising for the optical respective of the green light for the cut-off filter as well as optoelectronic device applications.