All-solution-processed mid-infrared electrochromics (ASPIRE) for thermoregulation with arbitrary curvatures

Area of Science:

• Materials Science
• Nanotechnology
• Energy

Background:

• Mid-infrared electrochromism is key for managing radiative heat transfer in buildings, industry, and personal devices.
• Current devices on planar substrates limit applications on 3D or curved surfaces due to air gaps and reduced efficiency.

Purpose of the Study:

• To develop an all-solution-processed fabrication method for mid-infrared electrochromic devices on arbitrary 3D surfaces.
• To enable objects to become electrically tunable thermal emitters with full surface conformity.

Main Methods:

• Utilized poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for electrochromic and charge-storage layers.
• Employed a heterogeneous mixed ionic-electronic conductor (HNO3-doped carbon nanotubes and hydrogel) for layer separation.
• Developed a layer-by-layer configuration for complete surface conformity and electrochemical stability.

Main Results:

• Achieved an emissivity tunability of 0.195 in the mid-infrared spectrum.
• Demonstrated apparent temperature modulation of 6.1 °C on planar and 2.3 °C on curved surfaces.
• Fabricated conformable electrochromic devices directly on 3D objects.

Conclusions:

• Established a generalizable strategy for outward-facing electrochromic devices on complex geometries.
• Opened new avenues for advanced light and heat management technologies using tunable thermal emitters.
• Overcame limitations of planar devices for applications requiring conformal coverage on 3D structures.