Low-light dye sensitized solar cells for connected devices

U.S.-based technology company Ambient Photonics has been awarded a $162 million loan guarantee by the U.S. Department of Energy (DoE) for the construction of a low-light solar cell production facility.

“We have not yet made a public announcement of the location for either our first or second factory,” the company’s CEO and founder Bates Marshall told pv magazine. “But we can disclose that both factories will be in the U.S., with the first located in California, and that funding from the DoE is for the second factory. We can also share that the first factory will be able to deliver tens of millions of cells and the second facility will have roughly ten times the capacity of the first.”

The company has developed dye sensitized solar cells that are used by internet-of-things (IoT) and smart home device companies and can be manufactured in sizes from 5cm² to 225cm² and in arbitrary rectangular sizes to fit any device and satisfy different power requirements. 

“Ambient works with several of the largest smart home and IoT device manufacturers in the world, who use our products to improve the functionality and sustainability profiles of their products,” Marshall went on to say. “Since many of Ambient’s customers will be debuting products in a few weeks at CES, which is an annual trade show organized by the U.S. Consumer Technology Association, we would like to not share any names at this time, out of respect for their upcoming announcements.”

The solar cells are claimed to eliminate the costs associated with replaceable batteries in consumer electronics, generate three times more power than amorphous silicon cells, and have a 90% higher conversion efficiency than other devices in low-light conditions. “Our selling price is competitive with high volume pricing per watt from conventional low-power commodity, Chinese-made, amorphous silicon indoor PV cells,” the CEO also explained.

Under illumination at 200 lux, the solar cell has a maximum power of 140 μW, an open-circuit voltage of 870 mV, and a short-circuit current of 200 μA. “Ambient’s unique advantage is its extremely high power density – 15mW/cm² at 200 W linear, with respect to illumination of 25 to 1,000 lux, which is comparable performance to gallium arsenide and more than three times the performance of conventional amorphous silicon indoor PV cells,” Marshall emphasized, noting that the devices are able to deliver power across all types of illumination sources, including LED, fluorescent, incandescent and diffuse natural light.