Enhancement of Optoelectronic Properties of Electrospun PVA Fibers by Adding Zinc and Cobalt Ions for Photodetection Applications

Abstract

In this work, polyvinyl alcohol (PVA) nanofibers dual mixed with zinc (Zn) and cobalt (Co) ions were prepared using an electrospinning technique with a precursor solution consisting of, citric acid, and zinc acetate. A polycrystalline structure was revealed for all samples, with peaks corresponding to the semi crystalline-PVA. The branched fibers of mean diameters increased with increasing Co ratio were shown. When the cobalt concentration was increased, the direct bandgap energy decreased from 3.2 to 2.3 eV. A conversion from p- to n-type conductivity was proved with increasing Co ratio. An increase in photoconductivity was observed in the prepared films with increasing Co ratio. The fabricated photodetector demonstrated excellent stability and reproducibility with a notable sensitivity of 503.8% under 380 nm illumination wavelength with a power density of 5.02 mW/cm² for the sample prepared at Co:Zn atomic ratio of 4:6.