Advancing Energy Efficiency in Smart Windows via Dual-Responsive Electro-Thermochromism

Area of Science:

• Materials Science
• Energy Science
• Optoelectronics

Background:

• Net-zero buildings require advanced dynamic smart windows.
• Existing electrochromic (EC) and thermochromic (TC) windows have limitations in optical modulation.
• Current technologies struggle with broad solar spectrum modulation due to absorption mechanisms.

Purpose of the Study:

• To design and assemble a dual-responsive electro-thermochromic smart window.
• To couple Prussian blue (PB) electrodes with a hydroxyl cellulose-based hydrogel electrolyte (HPC).
• To achieve significant optical and solar modulation for energy efficiency.

Main Methods:

• Formulation of HPC hydrogel electrolyte for enhanced properties.
• Coupling PB electrode with HPC hydrogel.
• Assembly of the dual-responsive smart window.
• Testing of transmittance modulation, mechanical stability, and ionic conductivity.

Main Results:

• HPC hydrogel achieved 83% TC transmittance modulation, 514% strain, and 62.58 mS/cm ionic conductivity.
• PB electrode exhibited high coloration efficiency (108.21 cm²/C) and fast switching kinetics (5s/6.8s).
• The smart window demonstrated 87.3% visible-light and 50.5% solar modulation, reducing annual energy consumption by 35%-55%.

Conclusions:

• The developed dual-responsive smart window offers four operating modes for coupled opto-thermal regulation.
• This technology significantly reduces building energy consumption, achieving savings up to 129 MJ m⁻².
• The study inspires future energy-efficient optoelectronics for decarbonization efforts.