Characteristics of ZnO–SnO2 Composite Nanofibers as a Photoanode in Dye-Sensitized Solar Cells

Composite materials are aimed to combine properties of their components to achieve a desired device functionality; however, synthesizing them in morphologies such as one-dimensional nanofibers is challenging. This article compares optical and electrical properties of ZnO–SnO 2 composite nanofibers (CNFs) synthesized by electrospinning technique for energy-harvesting applications with similar CNFs (TiO 2 –SnO 2 ) and their single-component nanofibers (NFs). The composite formation is confirmed by X-ray and electron diffraction, energy-dispersive X-ray, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy analyses; the morphology is examined by HRTEM and field-emission scanning electron microscopy. The electrochemical properties of the CNFs are studied by cyclic voltammetry, absorption spectroscopy, and electrochemical impedance spectroscopy. The CNFs behaved as a single semiconducting material of band gap ∼3.32 (ZnO–SnO 2 ) and ∼3.15 (TiO 2 –SnO 2 ) eV. The CNFs showed superior photoconversion efficiency (∼5.60% for ZnO–SnO 2 and ∼8.0% for TiO 2 –SnO 2 CNFs) compared to its binary counterparts SnO 2 (∼3.90%), ZnO (∼1.38%), and TiO 2 (∼5.1%) when utilized as photoanodes in dye-sensitized solar cells.