Influence of Synthesis-Dependent Structural Morphology on Performance of Natural Dye-Sensitized ZnO Solar Cells

Abstract

ZnO nanostructures were synthesized by solvothermal (STT), solution combustion (SCT), and template synthesis (TS) techniques, showing the formation of rod-like, dot-like, and wire-like morphology. Pure-phase wurtzite structure was observed for STT and SCT samples, and mixed-phase wurtzite structure for the TS sample. Strong excitonic peaks appeared for STT and TS samples, whereas the excitonic peak tended to shift for the SCT sample. Dye-sensitized solar cell device structures using natural anthocyanin dye were fabricated and their I-V characteristics studied. The ZnO nanowire-based device showed the maximum open-circuit voltage (V-oc) and short-circuit current density (I-sc) in comparison with the rod-like and flake-like ZnO nanostructures. The photoconversion efficiency (PCE) was found to be 3.2%, 4.4%, and 5.4% for the rod-, dot-, and wire-like morphology, respectively. The enhancement in the PCE can be attributed to increased charge collection at the interface of the ZnO photoanode and electrolyte layer.