Researchers have developed advanced lead-free semiconductors for solar cells, based on complex lead halides with a perovskite inspired structure.
The results of the study from researchers at Skolkovo Institute of Science and Technology (Skoltech), SB RAS Nikolaev Institute of Inorganic Chemistry, and RAS Institute for Problems of Chemical Physics were published in the Journal of Materials Chemistry A. The solar cells are based on complex lead halides with a perovskite inspired structure.
The light-conversion performance of solar cells
The solar cells have benefits such as their low cost, ease of manufacturing and enhanced light-conversion efficiency of >24%. However, there are obstacles to overcome before they are able to be mass produced and widely used, such as the toxicity and low stability of complex lead halides.
Researhcers are working on designing lead-free photoactive materials based on bismuth and antimony halides. So far these solar cells have displayed poor light-conversion performance. The researchers on this study showed that the reason for this is the non-optimal structure of the bismuth and antimony compounds.
Professor Pavel Troshin of the Skoltech Center for Energy Science and Technology explained: “We found out that unhindered vertical transport of holes and electrons, which is essential for efficient operation of solar cells, is prevented by the low dimensionality of the anionic sublattice in these compounds, which is typically 0D and sometimes 1D or very rarely 2-D. As a consequence, this class of materials can work efficiently in lateral photodetectors but not in solar cells.”
The new lead-free semiconductors for solar cells
The team also designed a new family of solar cell materials, which are based on the perovskite-like complex antimony bromides, ASbBr6(where A is a positively charged organic ion).
According to Skoltech, “the ASbBr6-based solar cells have exhibited record-high light-conversion efficiency for antimony and bismuth halides. The results of this study were published in the journal Advanced Energy Materials.”