Influence of nanoparticle addition to electrical properties of TCO films produced using electrospinning technique

In this study, the effect of nanoparticle addition on morphology and electrical properties electrospun nanofibers coated on transparent conductive oxide glass, namely, Indium Tin Oxide (ITO) has been investigated. For this purpose, an aqueous solution of Polyvinyl Alcohol (PVA) was prepared and nanoparticles of silver, zinc oxide, and titanium dioxide were added in the range of 3, 5, 10 and 20 wt.% under the magnetic stirring action. Then, prepared nanoparticle doped PVA solutions were electrospun and coated on ITO glass for 1 h. Morhological characteristics of nanoparticle containing fibers in films were investigated using scanning electron microscope and the resistance and resistivity values of obtained thin films were measured. It has been observed that the nanoparticles displayed agglomeration in PVA fibers and the size of the agglomerated regions increased as the content of nanoparticle in solution increased. The smallest size of the agglomerated region in all type of solutions was seen in TiO2 added fibers. As low as 643.7 ± 85.5 nm agglomerate size was detected in 3 wt.% TiO2 added PVA solutions. Likewise, the smallest fiber diameter size and more homogenous fiber size distribution was observed in TiO2 added fibers. For example, the average fiber diameter were found to be around 370, 376 and 380 nm for TiO2, ZnO and Ag nanoparticle doped fibers by 3 wt.%, respectively. Less agglomeration and homogenous fiber size distribution in TiO2 doped fibers influencedthe electrical conductivity of thin film deposited on ITO glasses positively as well. In all of the thin films containing fibers doped with different amounts of nanoparticles, the resistance and the resistivity values decreased by decreasing the content of nanoparticles. For the TiO2 doped fiber containing film, the resistance became equilivalent to resistance of ITO glass (34 ohm) at 10 wt.% TiO2 addition, below which the resistance of the thin film decreased well beyond the resistance of ITO glass as targeted. On the other hand, for the thin films containing fiber doped with ZnO and Ag nanoparticles, ITO resistance value was reached when the nanoparticle content decreased down to 5 wt.%.