Flexible solar cells that cover a car within reach after breakthrough

11 Sep 2019

Image: © minicel73/Stock.adobe.com

Electric cars of the future could be covered almost entirely in solar cells following a substantial breakthrough in flexible solar cells.

Researchers at the University of Warwick believe their latest creation could be revolutionary for the auto industry. In a paper published to Advanced Functional Materials, they described the forging of solar cells that use mixtures of organic molecules to absorb sunlight and convert it to electricity.

Most importantly, this solar cell design can be applied to curved surfaces, such as the body of a car, challenging conventional thinking about one of the key components of their design.

A typical organic solar cell consists of a thin film of organic semiconductor between two electrodes. However, it has long been assumed that 100pc of the surface of each electrode should be electrically conductive to maximise the efficiency of charge extraction.

Now, the researchers have shown that these electrodes only need as little as 1pc of their surface area to be fully effective.

This, the researchers said, opens the door to using a whole range of composite materials at the interface between electrodes and the light-harvesting organic semiconductor layers to improve device performance and reduce costs.

Close to commercialisation

In testing, they were able to show that this dramatic reduction in necessary surface area with significant charge could be achieved as long as the conducting regions aren’t too far apart.

“This new finding means composites of insulators and conducting nanoparticles such as carbon nanotubes, graphene fragments or metal nanoparticles, could have great potential for this purpose, offering enhanced device performance or lower cost,” said Dr Dinesha Dabera.

“Organic solar cells are very close to being commercialised but they’re not quite there yet, so anything that allows you to further reduce cost whilst also improving performance is going to help enable that.”

One of the benefits of organic solar cells is that they are potentially very environmentally friendly. This is because they contain no toxic elements and can be processed at low temperature using roll-to-roll deposition, resulting in a low carbon footprint.

Lead researcher on the project, Dr Ross Hatton, said that this design will help suit a purpose that conventional solar cells simply don’t.

“Conventional silicon solar cells are fantastic for large scale electricity generation in solar farms and on the roofs of buildings, but they are poorly matched to the needs of electric vehicles and for integration into windows on buildings, which are no longer niche applications,” he said. “Organic solar cells can sit on curved surfaces, and are very lightweight and low profile.”

Colm Gorey was a senior journalist with Silicon Republic