Visible-Near Infrared Independent Modulation of Hexagonal WO₃ Induced by Ionic Insertion Sequence and Cavity...

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Dual-band electrochromic materials offer independent control of sunlight and solar heat.
• Existing materials face limitations, and their regulation mechanisms are poorly understood.
• Need for advanced materials for dynamic optical and thermal management.

Purpose of the Study:

• To introduce and investigate the visible-near-infrared (NIR) independent regulation capabilities of hexagonal tungsten oxide (h-WO3).
• To establish a structure-activity relationship linking microscopic properties to macroscopic dual-band electrochromic performance.
• To demonstrate the potential of h-WO3 for energy-efficient dynamic temperature control.

Main Methods:

• Synthesis and characterization of hexagonal tungsten oxide (h-WO3).
• Investigation of ion intercalation processes and cavity characteristics.
• Electrochemical testing to evaluate dual-band electrochromic performance, including switching speeds and capacities.
• Device fabrication and testing for dynamic temperature control.

Main Results:

• h-WO3 demonstrates unprecedented visible-NIR-independent regulation, enabling distinct "bright," "cool," and "dark" modes.
• Established a structure-activity relationship correlating ion insertion and cavity properties with electrochromic performance.
• Achieved broadband full shielding from 550 to 2000 nm, the widest reported for dual-band electrochromics.
• Demonstrated high discharge capacity (270.9 mAh m⁻² at 0.25 A m⁻²) and efficient switching between modes.
• Constructed device achieved a dynamic temperature control range of 10.5 °C.

Conclusions:

• h-WO3 offers a novel platform for independent visible and NIR light modulation.
• The established structure-activity relationship provides a pathway for designing advanced electrochromic materials.
• The superior performance and energy efficiency highlight the significant potential of h-WO3 for practical applications in smart windows and energy management.