One factor of immense importance for many technical applications is the power density. This means the ability of solar cells to generate a high electrical output in relation to their own weight. The output of the new foil from the laboratory of the researchers in Linz is much higher than from conventional solar cells on a silicon basis.
In comparison, the solar-powered aircraft “Solar Impulse 2" has such conventional solar cells. The 135 micrometer cells are as thick as a piece of paper. The new foil is only three micrometers, thus four times thinner than plastic wrap. Their efficiency at twelve percent is still considerably lower than that of the solar-powered aircraft, but its power density is ten times higher due to their low weight.
Electrodes of solar cells on a perovskite basis corrode very quickly due to moisture. For this reason, the cells are usually protected by rigid layers of glass. In order to have a thin and flexible solar cell, a new type of electrode coating made of chromium oxide was developed which makes solar cells resistant to corrosion for at least several days.
According to the study, the foil can even be stretched and crumpled without any major loss of output. One more advantage is that it can be produced on a wide scale and above all cheaply with relatively simple means.