Fabrication of Sodium-Doped ZnO Nanorods and Investigation of Their Physical Properties as Electron Transport Layers for Dye-Sensitized Solar Cells

Abstrak

Sodium-doped ZnO nanorods were fabricated on fluorine-doped tin oxide (FTO) substrates by a self-assembly process using NaOH as the sodium source. Undoped ZnO and Na-doped ZnO with NaOH concentrations of 0.01, 0.015, and 0.02 M were prepared and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrical resistivity measurements. SEM showed vertically oriented ZnO nanorods with diameters that increased with Na doping, from 94.08 nm for undoped ZnO to 159.59 nm at 0.02 M NaOH. The estimated nanorod thicknesses were 4086.67, 4953.52, 2049.83, and 1263.38 nm for undoped ZnO, 0.01, 0.015, and 0.02 M NaOH, respectively. XRD confirmed the hexagonal wurtzite structure with a dominant (002) orientation. The crystallite size estimated from the (002) reflection increased from 112.4 nm for undoped ZnO to 156.9, 157.0, and 252.1 nm for 0.01, 0.015, and 0.02 M NaOH, respectively. Resistivity increased from 0.5868 Ω cm for undoped ZnO to 17.51, 17.62, and 24.11 Ω cm with increasing NaOH concentration. These results demonstrate that Na doping systematically modifies the morphology, crystallinity, and electrical resistivity of ZnO nanorods, providing a basis for tailoring ZnO nanorod layers as electron-transport materials for DSSC applications.