Scientists use inkjet printing to produce solar cells

Solar energy may soon become easier to capture, say researchers who have developed a novel method to produce solar cells using inkjet printing.

Oregon State University researchers have come up with a technology similar to that commonly used to print documents and photos.

They say their method is quicker and less expensive than traditional solar cell manufacturing techniques.

It could also reduce raw material waste by 90%, they add.

As people move away from conventional combustion-type technologies, more attention is paid to renewable energy types, and solar energy is one of them.

It is known as a clean and sustainable form of energy, but this is offset by the manufacture of solar panels which is an expensive and complicated process.

Finding a balance between costs of production and efficiency could become key to future manufacture of solar cells, and many scientists around the world have been concentrating on developing new materials and methods to do that.

The recent inkjet approach is one of those novel methods.

If efficiency and costs can be balanced, then lower efficiency cells become attractive”

"This is very promising and could be an important new technology to add to the solar energy field," said Professor Chih-hung Chang, the lead author of the study, which appeared in Solar Energy Materials and Solar Cells journal.

The team used chalcopyrite - a material composed of copper, indium, gallium and selenium and also known as CIGS. It has a much greater solar efficiency than silicon, currently used to manufacture solar panels.

The researchers then printed chalcopyrite onto the surface of the cell, applying a technique similar to a common inkjet approach, but with a special type of ink.

They managed to produce solar cells of 5% efficiency - and say that in future, they will aim to increase this figure to about 12% to make the product commercially viable.

Wei Wang, one of the scientists, told BBC News that the main advantages of the method were the ease of manufacturing and low cost.

"We produced CIGS solar cells using cheap inkjet printing under normal conditions," she said.

Also, she added, there was almost no waste in the process - unlike with a more expensive method of vapour phase deposition.

Professor Chang agreed that the waste issue was crucial.

"Some of the materials we want to work with for the most advanced solar cells, such as indium, are relatively expensive," he said.

"If that's what you're using you can't really afford to waste it, and the inkjet approach almost eliminates the waste."

CIGS cells produced by conventional means typically have an efficiency of 15-18%, but the methods of manufacturing are known to be a lot more time-consuming, or involve expensive vacuum systems or toxic chemicals.

An alternative to CIGS is silicon panels.

"The best cells that we put on house roofs at the moment are conventional silicon cells and those have an efficiency from 20 to 25% routinely, but the manufacturing costs and materials costs are extremely high," said Dr Martyn McLachlan from Imperial College, London.

He thinks that, although it is less efficent, the cheap manufacturing costs of the inkjet approach means it is a "significant development".

"If efficiency and costs can be balanced, then lower efficiency cells become attractive," he said.