Chitosan-Porphyrin Nanocomposite Films: Preparation, Characterization, and Optical Properties

In this study, porphyrin was prepared and doped with chitosan biopolymer using the solution casting process at various weight percentages (5 and 10 wt% CS-PP). The structural characteristics of the nanocomposite material were carefully examined using FTIR, SEM, and XRD. The presence of the distinctive chitosan peaks was confirmed by FTIR spectra; these peaks were altered by contact with porphyrin molecules. The chitosan surface displayed noticeable morphological changes on the SEM graphs, which result from surface interaction with porphyrin active sites. Moreover, XRD showed structural enhancement in the crystallinity of chitosan by incorporating porphyrin molecules. The nanocomposite films' optical characteristics, including refractive index, energy band gap, and optical dispersion parameters, were also investigated. It was observed that the band gap of pure chitosan is significantly reduced upon the addition of porphyrin nanocomposite. The increase of refractive index with increasing porphyrin nanocomposite doping is evidence for the formation of new energy states and thus decreasing the energy band gap of chitosan.