Carboxymethylcellulose/polyvinylpyrrolidone filled with Al-doped ZnO nanoparticles as a promising film for optoelectronic applications

With the aim of developing sustainable cellulose/polyvinyl pyrrolidone (carboxymethyl cellulose (CMC)/PVP) films for optoelectronic applications, Al-doped ZnO nanoparticles were incorporated into CMC/PVP films to create a synergistic effect arising from the excellent electrical properties of Al and the outstanding optical features of ZnO. Zn 0.95 Al 0.05 O (ZAL) nanoparticles were synthesized by sol–gel technique and then incorporated into CMC/PVP at various ratios via a solution casting method. The X-ray and selected-area electron diffraction results confirmed the formation of ZAL in wurtzite hexagonal phase with an average grain size of 19 nm. The infrared spectra showed an overlap between functional groups that proves the interaction between the CMC/PVP blend and the particles. The scanning electron microscopy images of the films revealed a change in the film surface in response to the filler concentration. The optical bandgap was gradually red-shifted with increasing the ZAL concentration, whereas the Urbach energy showed an opposite trend. The refractive index was investigated according to Sellmeier's and single-oscillator energy models. Two secondary relaxations (γ and β) that became faster upon filling were identified by dielectric spectroscopy. Overall, the incorporation of ZAL particles enhanced the optical parameters of the films in the THz range. • (CMC/PVP) x (ZNO:0.05Al) successfully prepared by casting technique. • Boosted thermal stability was indicated by increasing activation energy. • Tunable band gap suitable for photocatalysis and optoelectronic applications. • Two relaxation processes were (γ and β) were detected. • All optical parameters are enhanced in THZ range.