Stable, eco-friendly solar cells could be made with tin-based perovskites: Study
Researchers have explored the ion density in four different, widely used perovskite compounds and discovered significant differences. They found that tin perovskite semiconductors produced with an alternative solvent had a particular low ion density — only one tenth that of lead perovskite semiconductors.
Their approach hints that tin-based perovskites could be used to make solar cells that are not only really environmentally friendly but also very stable.
The work by researchers from HZB and the University of Potsdam provides a compelling argument for paying more attention to tin-based perovskites. One of the main reasons for the insufficient stability of perovskite solar cells to date is the presence of mobile halide ions in the material. As halide ions migrate, the material degrades, and the solar cell’s efficiency decreases over time.
Insufficient stability of perovskite solar cells
One of the main reasons for the insufficient stability of perovskite solar cells to date is the presence of mobile halide ions in the material. As halide ions migrate, the material degrades, and the solar cell’s efficiency decreases over time, according to the research team.
“We found not only that tin-based perovskites have a lower concentration of mobile ions but also that they intrinsically exhibit a degradation time five times slower than that of lead-based perovskites,” said Dr Artem Musiienko, head of a research group at HZB.
“The tin perovskite materials were produced in the HZB’s Hysprint laboratory. One of the tin perovskites was synthesized using a dimethyl sulfoxide (DSMO) solvent and the other using an alternative DMF-DMI solvent. The solvent variation approach was used to demonstrate a route for avoiding tin oxidation due to strong DMSO coordination, as previously shown in several investigations.”
Excellent stability during operation
The research team also discovered that the lead-based perovskite exhibited the greatest ion density. This density was slightly lower in the lead-tin mixture and the tin perovskite. A big surprise was by the tin perovskite sample that had been produced using the alternative solvent, according to a press release.
“This was really unexpected: these FASnI3 solar cells have ten times fewer mobile ions than the Pb-based solar cells. We also found that they exhibited excellent stability during operation for over 600 hours,” said Shengnan Zuo, a PhD student in the team of Musiienko.
Perovskite solar cells widely regarded as next generation photovoltaic technology
The team also maintained that perovskite solar cells are widely regarded as the next generation photovoltaic technology. However, they are not yet stable enough in the long term for widespread commercial use. One reason for this is migrating ions, which cause degradation of the semiconducting material over time.
“We are convinced that tin-based perovskites have enormous potential and that investigating these materials is a very good idea. There are chances to significantly increase their efficiency and stability. This study paves the way for the development of innovative, stable thin-film solar cells with suppressed ion migration,” said Musiienko.