Chromatic-Invariant Photothermal Fabrics Enabled by Narrow-Bandgap Organic Semiconductors for Wearable Solar Energy Harvesting.

The increasing popularity of outdoor activewear has placed higher demands on its thermal comfort, multi-functionality, and esthetics. Existing photothermal fabrics for cold weathers are based on visible light absorption, which limits color design options. Herein, a chromatic-invariant photothermal material is developed and integrated onto fabrics to prepare novel photothermal clothing, achieving 4°C-8°C temperature increase within only 5 min under 1000 W m- 2 simulated solar irradiation. It exhibits strong absorption in the near-infrared region and effectively converts the radiation into thermal energy, while maintaining the original visual colors of fabrics due to high reflectivity across the visible spectrum. Additionally, this photothermal material does not compromise the original functionality of fabrics and is suitable for application on various types of fabric materials. Furthermore, the prepared fabric achieves a sterilization rate exceeding 95.3% after only 20 min of irradiation under 1000 W m- 2 standard simulated solar light to ensure hygiene during outdoor activities. These results demonstrate a versatile wearable strategy with integrated functionality and aesthetic appeal for maintaining personal thermal comfort in cold-weather outdoor scenarios.