TNO, TU Eindhoven, Imec and TU Delft have stacked independently operating silicon and perovskite solar cells to obtain a record-breaking efficiency of 30.1 percent. The researchers tweaked perovskite solar cells in such a way that they efficiently convert of UV and visible light, while letting 93 percent of near-infrared pass through for the silicon to convert. In this so-called four-terminal (4T) tandem devices, the perovskite contributes 19.7 percent points and silicon 10.4 percent points to the total.
In 4T tandem devices different solar technologies can be combined to improve yield with hardly any modifications. Additionally, the architecture makes it straightforward to implement bifacial tandems to further increase the yield. The researchers also combined their perovskite with other types of silicon solar cells and all stacks approached 30 percent yield.