Inkjet method could lower cost of producing solar energy cells

According to Oregon State’s Prof Chih-hung Chang, part of the advantage of using an inkjet printing technique, rather than depositing chemical compounds on a substrate through vapour phase deposition, is that less material is wasted.

‘Some of the materials we want to work with for the most advanced solar cells, such as indium, are relatively expensive,’ said Chang. ‘You can’t really afford to waste it, and the inkjet approach almost eliminates the waste.’

One of the most promising compounds that could be used to manufacture solar cells is called chalcopyrite, or ‘CIGS’ for the copper, indium, gallium and selenium elements from which it is composed. CIGS material one or two microns thick has the ability to capture the energy from photons about as efficiently as a 50-micron-thick layer made with silicon.

In their research, the researchers were able to print chalcopyrite onto substrates with an inkjet approach, producing a solar cell with a power conversion efficiency of about five per cent. They claim that, with more research, they should be able to achieve an efficiency of about 12 per cent, which would make a commercially viable solar cell.

In related work being performed in collaboration with Greg Herman, an Oregon State associate professor of chemical engineering, the engineers are studying other compounds that might also be used with inkjet technology and cost even less.