New solar cells ready to be made

Third-generation design abandons silicon, mimics photosynthesis for high performance

A third-generation solar cell that produces zero pollution in manufacture, requires less light intensity and works with lower angles of sunlight, was handed off from its Chinese creator on August 18 to a commercial manufacturer in Shenzhen.

The transfer indicates that the cells are approaching the point of practical application in intelligent buildings, transportation and the so-called internet of things.

Shenzhen Precision Light & Automatic Equipment Co purchased the technology for the dye-sensitized solar cells — whose performance is said to surpass competitors worldwide — for 100 million yuan ($15 million) from the Shanghai Institute of Ceramics, under the Chinese Academy of Sciences.

In developing the cells over a 10- year period, researchers amassed more than 50 patents, all of which transfer to the Shenzhen company. The institute’s existing production line is also included in the deal.

The cell, which differs from those of the previous two generations in light acquisition and principle of power-generation, will serve in a wide variety of applications in modern cities — for example, in household electrical appliances, wearable devices, traffic lights and outdoor big screens — said Liu Yan, the institute’s Party chief.

“The first two generations of solar cells require strong and direct sunlight, but the third generation is able to work even indoors or on cloudy days or when the sunshine slants through. So it can be applied to more situations, such as an outdoor display screen that’s shaded by trees,” Liu said.

Shen Hujiang, a leading researcher of the project, added: “It can also be used for portable chargers, which will work despite environmental constraints. Portable chargers made with solar cells of the first or second generation can fail to work for tourists in jungles. But with the latest technology, a charger will continue to work.”

Crystalline silicon is the main ingredient in the first two generations of solar cells. Its semiconductor properties have been used to produce and transport electrical signals, Shen said.

In the third generation, however, researchers simulated the process of photosynthesis. Light received by the cells is converted into electrons and stored in a special material, and when the electrons gather and reach a certain amount, they will produce voltage and electrical current.

“The chemical materials used during manufacture are widely used in food products and cosmetics, so they are safe and environmentally friendly,” Shen said.

The cells were used in display screens at bus stops in Shanghai’s Pudong New Area as part of a pilot project.

“Shanghai is building its intelligent public transportation system, one element of which is screens to show when the next bus will arrive,” Liu said. “All the buses have been equipped with GPS. Screens with solar cells will be more energyconserving and sustainable,” Liu said.