Color and transparency-switchable semitransparent polymer solar cells towards smart windows

Area of Science:

• Materials Science
• Renewable Energy
• Optoelectronics

Background:

• Semitransparent polymer solar cells (ST-PSCs) offer unique light utilization but lack dynamic color tuning.
• Current ST-PSCs have a uniform color post-fabrication, limiting aesthetic applications.
• Smart window technology requires dynamic control over color and transparency.

Purpose of the Study:

• To develop ST-PSCs with reversible color-switching capabilities for smart window applications.
• To integrate a gasochromic tungsten trioxide/platinum (WO3/Pt) back reflector for dynamic control.
• To enhance power conversion efficiency (PCE) through light trapping in switchable ST-PSCs.

Main Methods:

• Fabrication of ST-PSCs incorporating a WO3/Pt gasochromic back reflector.
• Reversible switching between colored and bleached states using hydrogen exposure.
• Characterization of optical properties, switching speed, PCE, and average visible transmission (AVT).

Main Results:

• Achieved sub-second response speed for color and transparency switching.
• Demonstrated enhanced light trapping in the long-wavelength range.
• Reported PCE of 10.2% (colored) and 9.1% (bleached) with corresponding AVT of 25.4% and 33.8%.

Conclusions:

• First demonstration of ST-PSCs with simultaneous color-switching and light trapping functionalities.
• The developed smart windows meet aesthetic requirements for building-integrated photovoltaics.
• Gasochromic smart windows offer promising avenues for future ST-PSC development and commercialization.