Hydrothermal synthesis of hierarchical WO₃ nanostructures for dye-sensitized solar cells

Hierarchical architectures consisting of one-dimensional (1D) nanostructures are of great interest for potential use in energy and environmental applications in recent years. In this work, hierarchical tungsten oxide (WO₃) has been synthesized via a facile hydrothermal route from ammonium metatungstate hydrate and implemented as photoelectrode for dye-sensitized solar cells. The urchin-like WO₃ micro-patterns are constructed by self-organized nanoscale length 1D building blocks, which are single crystalline in nature, grown along (001) direction and confirm an orthorhombic crystal phase. The obtained powders were investigated by XRD, SEM, TEM and UV-Vis Spectroscopy. The photovoltaic performance of dye-sensitized solar cells based on WO₃ photoanodes was investigated. With increasing the calcination temperature of the prepared nanopowders, the light-electricity conversion efficiency (η) was increased. The results were attributed to increase the crystallinity of the particles and ease of electron movement. The DSSC based on hierarchical WO₃ showed a short-circuit current, an open-circuit voltage, a fill factor, and a conversion efficiency of 4.241 mA/cm², 0.656 V, 66.74, and 1.85 %, respectively.