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-SnO2 composite nanofibers (CNFs) synthesized by electrospinning technique for energy harvesting applications with similar CNFs (TiO2-SnO2) 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 similar to 3.32 (ZnO-SnO2) and similar to 3.15 (TiO2-SnO2) eV. The CNFs showed superior photoconversion efficiency (similar to 5.60% for ZnO-SnO2 and similar to 8.0% for TiO2-SnO2 CNFs) compared to its binary counterparts SnO2 (similar to 3.90%), ZnO (similar to 1.38%), and TiO2 (similar to 5.1%) when utilized as photoanodes in dye-sensitized solar cells.