Researchers develop new materials that could improve performance of perovskite solar cells, according to a report published on January 10, 2019.
Perovskite solar cells (PSCs) are widely preferred due to its power conversion efficiency to above 20 per cent. However, the performance of these cells are affected due to ion defects present in the perovskite material. As these defects move, the internal electric environment within the cell are affected.
In this study, researchers from the Universities of Portsmouth, Southampton and Bath developed a method that can be used to adjust the properties of the transport layers. This will encourage the ionic defects within the perovskite to move in such a way that they suppress recombination and lead to more efficient charge extraction. Researchers showed that performance of PSCs are strongly dependent on the permittivity and the effective doping density of the transport layers.
Dr. Jamie Foster from the University of Portsmouth said, “We found that ion movement plays a significant role in the steady-state device performance, through the resulting accumulation of ionic charge and band bending in narrow layers adjacent to the interfaces between the perovskite and the transport layers. The distribution of the electric potential is key in determining the transient and steady-state behavior of a cell.”
According to the researchers, PSCs that are made using transport layers with low permittivity and doping are more stable, when compared to the ones with high permittivity and doping. This is because such cells show reduced ion vacancy accumulation within the perovskite layers, which is associated with chemical degradation at the edges of the perovskite layer.