Black silicon boron emitter solar cells with EQE above 95% in UV

Silicon solar cells are known to suffer from poor UV response because of high reflectance combined with recombination at the front side of the cell - including heavily doped emitter. While black silicon (b-Si) has proven to be excellent technology to overcome the reflectance losses, it has been challenging to integrate it to PERC cells with recombination-free emitter without compromising the optical properties. Here we show that no such tradeoffs are needed when using boron emitter with proper surface passivation. We demonstrate a b-Si emitter that has saturation current as low as 33 fA/cm
²
resulting close to 100% EQE even down to 300 nm. This result should be interesting for the PV industry looking for further improvements in their current products.