Flexible TEMPO-cellulose/silver selenide nanocomposites with advanced optical, electrical, and antimicrobial
Ahlam I Al-Sulami1, Fatimah Mohammad H Al Sulami1, Reema H Aldahiri1
1College of Science, Department of Chemistry, University of Jeddah Jeddah 21589 Saudi Arabia.
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Transforming dielectric polymers into conductive or semiconductive materials opens new avenues for advanced and unprecedented applications. Herein, flexible films were fabricated from TEMPO-oxidized cellulose nanofibers/silver selenide (T-CNF/Ag2Se) nanocomposites. Ag2Se particles were in situ prepared in the presence of TEMPO-oxidized cellulose nanofibers to limit the Ag2Se formation within the nanopores of the TEMPO-oxidized cellulose nanofibers. XRD and FTIR patterns verified the effective embedding of Ag2Se nanoparticles within the T-CNF matrix, where Ag2Se crystallized exclusively in the orthorhombic β-Ag2Se phase. For optoelectronic applications, the optical features were investigated, and Ag2Se has a great impact on transmittance, reflectance, optical band gap, and Urbach energy of CNF. The transmittance was reduced from 10% to 2% in the visible region, while the optical band gap dropped from 4.46 eV for CNF to 2.65 eV for CNF/Ag2Se I. Compared with pure CNF, the CNF/Ag2Se I nanocomposites showed broader M″ peaks that shifted towards higher frequencies, indicating enhanced charge-carrier dynamics due to the additional conductive pathways introduced by the Ag2Se nanoparticles. At 313 K, conductivity followed the order of CNF < CNF/Ag2Se III < CNF/Ag2Se < CNF/Ag2Se II < CNF/Ag2Se I, with the conductivity increased by three orders of magnitude for CNF/Ag2Se I compared with that for the pure CNF. The antimicrobial performance of CNF/Ag2Se at different concentrations was evaluated, and it exhibited high toxicity against E. coli, S. typhimurium, and C. albicans, while S. mutans exhibited more resistance against the nanocomposite materials.
