Vacancy Engineering in Tungsten Oxide for Enhanced Temperature-Modulated Electrochromic Smart Windows.

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Effective temperature control relies on modulating visible (VIS) and near-infrared (NIR) radiation.
• Electrochromic materials face challenges in achieving strong NIR light absorption for enhanced thermal management.

Purpose of the Study:

• To develop an electrochromic material with high NIR absorbance for improved temperature modulation.
• To investigate the performance of Ag-doped tungsten oxide (Ag@WOx) in smart window applications.

Main Methods:

• Fabrication of Ag-doped tungsten oxide (Ag@WOx) utilizing enhanced local surface plasmon resonance.
• Assembly and testing of electrochromic smart windows.
• Theoretical confirmation of crystal structure modification using Density Functional Theory (DFT) calculations.

Main Results:

• Achieved high NIR absorbance in Ag@WOx, leading to a 6.3 °C temperature difference compared to untreated WOx.
• Demonstrated low transmittance (2.64% at 1800 nm) in dark mode for excellent temperature modulation.
• Obtained high optical modulation (91%) for efficient visible light transmission and fast switching speeds (9.9 s coloration, 7.4 s bleaching).

Conclusions:

• Ag@WOx is a promising material for high-performance electrochromic energy-saving smart windows.
• Enhanced local surface plasmon resonance in Ag@WOx significantly improves NIR absorption and thermal control.
• The material exhibits excellent cycling stability, with minimal decay after 20,000 cycles.