Constructing a Semi-Coherent TiO₂ Heterointerface for Rapid and Stable Dual-Band Electrochromism

Area of Science:

• Materials Science
• Nanotechnology
• Energy

Background:

• Dual-band electrochromic smart windows regulate visible (VIS) and near-infrared (NIR) light for energy savings and comfort.
• Current limitations include insufficient optical modulation, slow switching, and poor durability.

Purpose of the Study:

• To design and fabricate a hierarchical TiO2 nanorod/nanosheet (TNR/TNS) heterostructure film.
• To enhance optical modulation, switching speed, and cycling stability for smart windows.

Main Methods:

• A two-step in situ-oriented growth strategy was employed.
• Rutile-phase TiO2 nanorods were grown on FTO substrates, followed by epitaxial growth of anatase-phase TiO2 nanosheets.
• This created a porous heterostructure with a semi-coherent interface.

Main Results:

• The TNR/TNS composite film achieved 60.2% modulation at 1300 nm and 65.1% at 700 nm.
• Rapid switching kinetics and remarkable cycling stability were observed, retaining 92% modulation after 2000 cycles.
• Synergistic effects from structural buffering and efficient ion/electron transport contributed to performance.

Conclusions:

• The study demonstrates an effective strategy using crystal phase and interface engineering for high-performance electrochromic materials.
• The developed TNR/TNS film shows significant potential for energy-efficient architectural windows.