Hierarchically structured microspheres for high-efficiency rutile TiO(2)-based dye-sensitized solar cells

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Titanium dioxide (TiO2) is a crucial material in renewable energy applications, particularly in dye-sensitized solar cells (DSSCs).
• Developing efficient photoanode materials is key to enhancing solar cell performance.
• Controlling the morphology and structure of TiO2 at the nanoscale is essential for optimizing photovoltaic properties.

Purpose of the Study:

• To synthesize novel peachlike rutile TiO2 microsphere films.
• To investigate the role of polyethylene glycol (PEG) in controlling TiO2 morphology.
• To evaluate the performance of these TiO2 microspheres as photoanodes in DSSCs and improve their efficiency through post-treatments.

Main Methods:

• A facile, one-pot chemical bath route at low temperature (80-85 °C) was employed.
• Polyethylene glycol (PEG) was used as a steric dispersant to control microsphere formation.
• Dye-sensitized solar cells were assembled using the synthesized TiO2 microspheres, followed by post-treatments including calcination, TiCl4 treatment, and O2 plasma exposure.

Main Results:

• Peachlike rutile TiO2 microspheres composed of nanoneedles were successfully synthesized on fluorine-doped tin oxide substrates.
• The formation mechanism involved acidic conditions for nanoneedle growth and PEG's steric interaction to prevent aggregation and Ostwald ripening.
• Initial DSSC efficiency using the TiO2 microspheres was 2.55%, which increased to 5.25% after post-treatments.

Conclusions:

• The synthesized rutile TiO2 microspheres are promising photoanode materials for DSSCs.
• Post-treatments significantly enhance DSSC efficiency by improving TiO2 crystallinity, dye loading, and light scattering/trapping.
• The low-temperature, one-pot synthesis method offers a scalable approach for producing advanced TiO2 photoanodes.