Solid-State Solar Energy Conversion from WO₃ Nano and Microstructures with Charge Transportation and Light-Scattering Characteristics

Solar energy conversion devices composed of highly crystalline gel polymers with disk-WO₃ nanostructure and plate-WO₃ microstructures (D-WO₃ and P-WO₃, respectively) exhibited higher power conversion efficiency than those with a gel electrolyte. In this study, D-WO₃ and P-WO₃ were prepared using a hydrothermal process and their structural and morphological features were investigated for application in solar energy conversion devices. The P-WO₃ solid-state electrolyte significantly enhanced the cell performance owing to its charge transportation and light-scattering characteristics. The P-WO₃ solid-state electrolyte showed a power conversion efficiency of 6.3%, which is higher than those of the gel (4.2%) and D-WO₃ solid-state (5.5%) electrolytes. The electro-chemical impedance spectroscopy (EIS), intensity-modulated voltage spectroscopy (IMVS), diffuse reflectance, and incident photon-to-current conversion efficiency (IPCE) analysis results showed that the P-WO₃ solid-state electrolyte showed improved charge transportation and light scattering, and hence enhanced the cell performance.