Wearable solar powered clothing coming in the early 2020s

A group of Japanese researchers has developed a super-thin organic solar cell that can be heat-printed onto clothes just like a T-shirt design.

The cells could be used to power portable devices and wearable tech, eliminating the need to carry around a battery or adapter. Furthermore, if the cells were affixed to tents, they could provide electricity in the outdoors or during disasters, and can simply be folded up and put away when not being used.

At the Earth’s surface, the energy density is reduced to approximately 1,000 W/m2 for a surface perpendicular to the Sun’s rays at sea level on a clear day. However, there is less solar power from a vertical surface. Plus the current material is only 10% efficient. clothing that was completely covered with 10% efficient wearable solar might be able to generate 20-30 watts in brightest sunlight.

Japanese researchers have developed an ultraflexible organic photovoltaic (OPV) that achieves sufficient thermal stability of up to 120 °C and a high power conversion efficiency of 10% with a total thickness of 3 microns. By combining an inherently stable donor:acceptor blend as the active layer and ultrathin substrate and barriers with excellent thermal capability, we were able to overcome the trade-offs between efficiency, stability, and device thickness. The ultraflexible and thermally stable OPV can be easily integrated into textiles through the commercially available hot-melt process without causing performance degradation, thereby presenting great potential as a ubiquitous and wearable power source in daily life.

Power sources that are flexible enough to be attached onto curved and rough surfaces are one of the most promising solutions to supplying electrical power directly to Internet of Things sensors, wearable sensors, and electronic devices. As one of the thinnest, lightest, and most flexible photovoltaic technologies, organic photovoltaics (OPVs) are promising for extensive integration in various shapes and sizes, thus extending power sources from space-intensive to the prevailing wearable form of electronics.

The power conversion efficiency (PCE) of OPVs improved from 1 to 10% (1⇓⇓–4), which is considered a representative efficiency for widespread applications.

The ultrathin plastic substrate and barrier coatings with good thermal capability and low gas permeability further allow the operation of the cells and their storage in air or under harsh conditions over a long period. In combination with the mature hot-melt process in the apparel industry, our thermally stable and ultraflexible OPVs can greatly expand the possibilities of textile-compatible electronics.