Combining mixed titania morphologies into a complex assembly thin film by iterative block-copolymer-based sol–gel...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Titania (TiO2) thin films are crucial for energy applications.
• Controlling nanostructure in TiO2 films is key to enhancing performance.
• Hierarchical structures offer unique advantages for charge transport and surface area.

Purpose of the Study:

• To develop a method for creating custom hierarchically structured titania thin films.
• To combine foam-like structures with nanogranules in a thin film geometry.
• To evaluate the potential of these structures for photovoltaics and photocatalysis.

Main Methods:

• Sol-gel templating using poly(styrene-block-ethylene oxide) (P(S-b-PEO)) as a structure-directing agent.
• Iterative spin-coating steps to build the hierarchical structure.
• Scanning Electron Microscopy (SEM) for morphological analysis.
• Grazing-Incidence Small-Angle X-ray Scattering (GISAXS) for structural probing.
• Optical characterization to assess material properties.

Main Results:

• Successfully fabricated hierarchically structured titania thin films.
• Achieved a complex assembly combining foam-like structures and nanogranules.
• The mesoporous titania structure exhibits distinct holes of approximately 45 nm.
• SEM and GISAXS confirmed the hierarchical morphology and pore size.

Conclusions:

• The developed sol-gel templating and spin-coating method allows for precise control over titania thin film nanostructure.
• The resulting hierarchical titania films with 45 nm pores are promising for applications in photovoltaics and photocatalysis.
• Further optical characterization supports the potential utility of these tailored materials.