Using a highly sensitive method of measurement, HZB physicists have managed to localize defects in amorphous/crystalline silicon heterojunction solar cells. Now, for the first time ever, using computer simulations at Paderborn University, the scientists were able to determine the defects’ exact locations and assign them to certain structures within the interface between the amorphous and crystalline phases.
In theory, silicon-based solar cells are capable of converting up to 30 percent of sunlight to electricity – although, in reality, the different kinds of loss mechanisms ensure that even under ideal lab conditions it does not exceed 25 %. Advanced heterojunction cells shall affront this problem: On top of the wafer’s surface, at temperatures below 200 °C, a layer of 10 nanometer disordered (amorphous) silicon is deposited. This thin film is managing to saturate to a large extent the interface defects and to conduct charge carriers out of the cell. Heterojunction solar cells have already high efficiency factors up to 24,7 % – even in industrial scale. However, scientists had until now only a rough understanding of the processes at the remaining interface defects.
Read more at Phys.org