Brookite TiO2 nanoparticle films for dye-sensitized solar cells

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Titanium dioxide (TiO(2)) is a key material in photovoltaic applications.
• Brookite, a less common TiO(2) polymorph, offers unique properties for solar energy conversion.
• Developing efficient synthesis methods for brookite nanostructures is crucial for advancing solar cell technology.

Purpose of the Study:

• To synthesize pure brookite TiO(2) nanoparticles and porous films at low temperatures.
• To fabricate and characterize dye-sensitized solar cells (DSSCs) using brookite nanoparticle films.
• To investigate the effect of nanoparticle size and lanthanum doping on photovoltaic performance.

Main Methods:

• Soft solution growth method for brookite TiO(2) nanoparticle synthesis.
• X-ray diffraction (XRD) and Raman spectroscopy for structural confirmation.
• Spectrophotometry to determine the direct band gap (3.4 eV).
• Fabrication of DSSCs sensitized with N719 dye.

Main Results:

• Pure brookite nanoparticle porous films were successfully prepared.
• The films exhibited a direct band gap of 3.4 eV.
• A maximum conversion efficiency of 5.97% was achieved with larger brookite nanoparticles, surpassing anatase cells.
• Smaller brookite particles showed lower electron diffusion coefficients.
• Lanthanum doping reduced dye loading and overall current density.

Conclusions:

• Brookite TiO(2) nanoparticles are promising building blocks for efficient solar cells.
• Nanoparticle size significantly impacts photovoltaic performance, with larger particles yielding higher efficiency.
• Lanthanum doping negatively affects dye loading and current density in these brookite-based solar cells.