Researchers from Sweden's Linköping University and the Nanyang Technological University (NTU) in Singapore have developed high-quality films based on double perovskites, which demonstrate promising photovoltaic properties. Developing environmentally friendly perovskites has become important in solving the toxicity issue of lead‐based perovskite solar cells.

Lead-free double perovskite imageThe lead-free double perovskite solar cells (yellow, in the front) compared with the lead-based device (dark, in the background)

"Our colleagues at Nanyang Technological University in Singapore have shown that the charge carriers demonstrate long diffusion lengths in the material, which is necessary if the material is to be appropriate for the application of in solar cells," says the Linköping team.

The power conversion efficiency of the lead-free double perovskites solar cells is still quite low - only around 1% of the energy in sunlight is converted to electricity - but the research team has taken the first major step and developed a method to manufacture the active layer. "We have several good ideas of how to proceed to increase the efficiency in the near future," the researchers state.