One‐Step Reactive Sputtering of Novel MoOx Nanogradient Absorber for Flexible and Wearable Personal Passive Heating

Thermoregulating textiles as an emerging approach to promote people comfort have attracted significant attention in recent years. However, a simple, efficient, and cost‐effective strategy that can autonomously absorb sunlight without extra power supply to warm the human body is lacking. Herein, a novel nanogradient MoOx absorber (NMOA) on flexible polymers and wearable fabrics for personal passive heating is successfully fabricated via a simple one‐step reactive sputtering technique. The surface steady‐state temperatures of the NMOA coated on polymers and fabrics reach 78 and 90 °C under one sun illumination, confirming efficient solar thermal conversion, resulting from the superior absorption of NMOA. More importantly, the heating property of NMOA is on par with those of silver nanowire or carbon nanotube‐coated textiles that use the Joule heating effect applied with a high voltage supply. It is noteworthy that achieving a high temperature at a low voltage is difficult, and hence the use of NMOA presents significant advantages. Due to the outstanding spectrally selective property of NMOA, the textile enables a 11 °C temperature enhancement in a cold environment (2 °C). Together with its superior light‐absorbing ability and excellent adhesion nature, the NMOA could be very promising in thermoregulating flexible and wearable applications. A flexible, efficient, and scalable MoOx‐based solar absorber coating is fabricated by using a straightforward one‐step reactive sputtering process. The result reflects superior endothermic ability as well as good adhesion and bendable nature, which indicate potential for regulating human body temperature, and the outdoor cloudy nature condition achieves a 6 °C difference compared with bare fabric.