Crystalline/amorphous tungsten oxide core/shell hierarchical structures and their synergistic effect for optical...

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• High-performance electrochromic films are crucial for smart windows, requiring large color contrast and rapid switching.
• Tungsten oxide (WO3) is a promising material for electrochromic applications, but its performance can be limited by its structure.
• Hierarchical nanostructures offer potential for enhanced optical and electrical properties.

Purpose of the Study:

• To synthesize crystalline/amorphous WO3 core/shell (c-WO3@a-WO3) nanowire arrays.
• To investigate the synergistic effects of the core/shell structure on electrochromic performance.
• To optimize the synthesis for enhanced optical modulation, switching speed, and durability.

Main Methods:

• Hydrothermal synthesis to create crystalline WO3 cores.
• Electrodeposition to form amorphous WO3 shells, creating c-WO3@a-WO3 core/shell structures.
• Characterization of structural, optical, and electrochromic properties.

Main Results:

• The 1D c-WO3@a-WO3 core/shell nanowire arrays exhibited enhanced optical modulation, particularly in the infrared region.
• Optimized films showed significant optical modulation (e.g., 70.3% at 750nm, 42.0% at 2000nm, 51.4% at 10μm).
• Achieved fast switching speeds (3.5s and 4.8s), high coloration efficiency (43.2cm(2)C(-1)), and excellent cycling stability (68.5% after 3000 cycles).

Conclusions:

• The c-WO3@a-WO3 core/shell nanostructured film demonstrates a synergistic effect for superior electrochromic performance.
• This nanostructure provides a viable pathway for developing next-generation high-performance electrochromic materials for smart windows.
• The enhanced infrared modulation and fast switching speed are key advantages for advanced applications.