Flexible silicon solar cells could be rolled out on tricky to cover buildings

A new technique for producing silicon solar cells that are more than 24% efficient and yet can be rolled up like a sheet of paper has been demonstrated. The work could allow solar cells to be used in applications that currently use more expensive thin-film alternatives.

Crystalline silicon is an indirect-bandgap semiconductor, which means a photon travels further before being absorbed and forming an electron–hole pair than it would through gallium arsenide or a perovskite, for example. Many researchers claim that this makes it unsuitable for flexible or curved solar cells. Andrew Blakers at the Australian National University in Canberra, however, says this is fallacious, and that thin silicon can produce conformable or flexible cells from either spacing out the cells within a flexible matrix or tolerating crack formation – albeit with one or two percentage points lost in efficiency.