Dual-Function Smart Windows Using Polymer Stabilized Cholesteric Liquid Crystal Driven with Interdigitated Electrodes

Area of Science:

• Materials Science
• Optoelectronics
• Applied Physics

Background:

• Smart windows offer dynamic control over light and heat transmission.
• Existing smart window technologies have limitations in simultaneously managing visible and infrared light.

Purpose of the Study:

• To develop an electrically switchable window capable of dynamically controlling both visible light transmittance and infrared (IR) light reflection.
• To investigate the use of polymer stabilized cholesteric liquid crystals (PSCLCs) for this application.

Main Methods:

• Fabrication of a window device using PSCLCs sandwiched between patterned electrode substrates.
• Application of vertical alternating current (AC) electric fields to modulate visible light transmittance.
• Application of in-plane interdigital direct current (DC) electric fields to tune IR reflection bandwidth.

Main Results:

• Visible light transmittance was reduced from 90% to less than 15% by switching CLC texture to a scattering focal conic state.
• IR reflection bandwidth was dynamically adjustable from 158 nm to 478 nm by controlling helix pitch distortion.
• Both visible transmittance and IR reflection bandwidth were tunable via electric field strength and reversible upon field removal.

Conclusions:

• The developed PSCLC-based window offers on-demand control over both visible light and IR radiation.
• This technology presents a promising solution for advanced indoor light and heat management.
• Potential applications include energy-efficient green buildings and automotive windows.