Researchers Develop a Process to Control Instability in Perovskite Solar Cells

A team of researchers from the Australian Research Council Center of Excellence in Exciton Science claimed that they have developed a process that can help enhance the commercial use of perovskite cells. The research tackles bandgap instability due to light-induced phase segregation in mixed-halide perovskites that presents a major challenge for their future commercial use.

According to the research report, light-induced halide segregation is a process that leads to the formation of halide-rich domains and localized variations in the material bandgap. This decreases the charge mobility and carrier lifetime of mixed-halide perovskites.

The researchers explained that high illumination intensities could reverse the photo-induced halide-ion segregation (PHS) to control the bandgap of a mixed-halide perovskite single-crystal through optimizing the input photogenerated carrier density.

“The ability to control the halide-ion composition with light intensity provides new opportunities to utilize mixed-halide perovskites in concentrator as well as tandem solar cells, optical memory applications, and high-power light-emissive devices,” said the researchers.

In the report, the researchers stated that a range of stable photoluminescence (PL) energy could be reached by adjusting the input excitation power, which shows that the halide ion distribution is correlated with the excitation power. Photoluminescence is light emission from any form of matter after the absorption of photons.

The researchers noted that the potential to manipulate the halide-ion distribution with light intensity in perovskites provided a viable method for achieving compositional uniformity in mixed-halide perovskites.

“We provided evidence that the halide-ion distribution in mixed-halide perovskite single crystals can be tuned from a segregated state to a completely homogeneous state by increasing the input carrier density, and we have developed a lattice model that explains this behavior by the presence (or not) of polaron-induced strain gradients,” said the researchers.

In May 2020, the researchers at Iowa State University came up with an innovative way to stabilize perovskite cells at high temperatures. They developed a technique that has made the material more stable at higher temperatures.

Previously, Australian scientists, led by members of the ARC Center of Excellence in Exciton Science, published a research paper stating that they had succeeded in producing semi-transparent perovskite solar cells that generate electricity. This breakthrough could allow for windows in buildings and automobiles to generate electricity.

Image credit: Stephan Kambor, CC BY-SA (2.5)