Perovskite flaws revealed, points to major efficiency upside

The potential of perovskites in solar applications continues to be explored, with the latest research from the University of Washington and Oxford University indicating that the conversion efficiency of the material could be enhanced greatly. In a study published on April 30, the researchers found the existence of defects in the perovskite material that limit electron movement and therefore conversion efficiency.

Not only did the researchers discover the flaws, they also found they the flawed areas could be “turned on” using a chemical treatment. This could, in turn, boost the efficiency of the perovskite device.

“Surprisingly, this result shows that even what are being called good, or highly-efficient perovskite films today still are ‘bad’ compared to what they could be. This provides a clear target for future researchers seeking to improve and grow the materials,” said David Ginger, a professor of chemistry at the University of Washington.

Pervoskite has already achieved efficiencies of around 20% in the laboratory in a very short space of time. That further gains could be made and in such a short period of time indicates just how great the promise of the PV material is.

The flaws were identified by the research team by applying confocal optical microscopy. This means that fluorescent images are correlated with those obtained through using a electron microscope to show up the “dark” or flawed areas. Ginger said that the technique can show up previously undetected flaws in the perovskite. Confocal optical microscopy is normally used in the field of biology.

While there is much promise in the research being carried out on perovskites, sensitivity to water and therefore durability remains a major challenge.

The research findings were published in the journal Science. It was carried out at the University of Washington’s Clean Energy Institute.

Tandem crystalline silicon/perovskite applications are currently being explored in laboratories, including the University of New South Wales under Martin Green and commercially by startups such as Oxford PV.