Analysis of the electron transport properties in dye-sensitized solar cells using highly ordered TiO ₂ nanotubes and TiO ₂ nanoparticles

This study uses TiO ₂ nanoparticles and highly ordered anatase TiO ₂ nanotubes (AOTnt) as thin film photoanodes for dye-sensitized solar cells (DSSCs). DSSCs are assembled by single-layer and double-layer films of photoanodes and their electron transfer performance is compared. TiO ₂ nanoparticles were fabricated by the sol-gel method, and AOTnts were grown on titanium foil. This study uses TiO ₂ nanoparticles or AOTnts to prepare single-layer photoanodes and TiO ₂ nanoparticles coated on an AOTnt film to fabricate double-layer photoanodes. These three different photoanodes are soaked in dye and assembled into DSSCs, and their open-loop voltage recession, electrochemical impedance, lifetime, life cycle, and effective diffusion coefficient are measured. Electron transfer efficiency of the photoanodes and light harvesting efficiency are further analyzed. The results show that the electron transfer efficiency, open-loop voltage recession, lifetime, life cycle, and effective diffusion coefficient of the DSSCs assembled using double-layer photoanodes (AOTnt-TiO ₂) are superior to those of single-layer photoanodes (TiO ₂ or AOTnt).