A New Flexible Solar Panel Material Is 15 Times Thinner Than Paper

And it could work in wearables and light aircraft.

Researchers at Stanford University are developing an efficient new solar panel material that is fifteen times thinner than paper, a press statement reveals. 

Made using transition metal dichalcogenides (TMDs), the materials have the potential to absorb a higher level of sunlight than other solar materials at the same time as providing an incredibly lightweight alternative to silicon-based solar panels.

Searching for silicon alternatives

The researchers are part of a concerted effort within the scientific community to find alternative solar panel materials to silicon. Silicon is by far the most common material used for solar panels, but it's heavy and rigid, meaning it isn't particularly well suited to lightweight applications required for aircraft, spacecraft, electric vehicles, or even wearables.

The team of researchers at Stanford was able to develop an active array only a few hundred nanometers thick. They outlined their new findings in a paper published in Nature Communications. The new array includes the TMD as well as contacts of gold encased in a layer of conducting graphene that is only a single atom thick. All of that is then placed inside a flexible, anti-reflective polymer that improves light absorption. The TMD cells themselves are less than six microns thick.

"Imagine an autonomous drone that powers itself with a solar array atop its wing that is 15 times thinner than a piece of paper," said Koosha Nassiri Nazif, co-lead author of the study. "That is the promise of TMDs."

Unleashing the potential of TMDs

Researchers have so far struggled to fully unleash the potential of TMDs. Obstacles exist when it comes to manufacturing and transporting the incredibly lightweight material without damaging it. The main issue, however, is that silicon solar panels currently convert roughly 30 percent of sunlight into electricity, while TMDs only convert about 2 percent. Though TMDs have great potential for enabling a wide range of solar applications, researchers will have to greatly improve their efficiency. 

The new Stanford material goes some way towards bridging that gap by achieving 5.1 percent power conversion efficiency. The crucial point though in the researchers' new paper is that they believe they can optimize their material to reach 27 percent efficiency, meaning it would be comparable to the best solar panels on the market today. The prototype material also reached a 100-times greater power-to-weight ratio than any TMDs developed so far.

"Silicon makes up 95 percent of the solar market today, but it's far from perfect. We need new materials that are light, bendable, and, frankly, more eco-friendly," said Krishna Saraswat, senior author of the paper.

TMDs contain no toxic chemicals and are also biocompatible, meaning they can be used for wearables that come in contact with human skin. Their biggest benefit however is the fact that they are incredibly thin and flexible, making them cheaper at the same time as being moldable to irregular shapes. 

For electric vehicles, this new material could equal a much greater range. Such a lightweight material could greatly enhance the development of solar electric vehicles (SEVs), such as the Lightyear One, which promises to run for months without being plugged into a charger thanks to its solar panels. The material could be used to charge any number of objects, including small wearables, robots, aircraft, and spacecraft. 

Source: https://interestingengineering.com/a-new-flexible-solar-panel-material-is-15-times-thinner-than-paper