Researchers from the KAUST Solar Center have monitored the impact of compositional changes on the structural organization and photovoltaic properties of perovskite thin films in situ. The team has reached a conclusion that may benefit perovskite solar cells in the future - that changes in composition affect light-harvesting layer crystallization and perovskite solar cell efficiency.

Sequence of fabrication of a perovskite thin film from precursor solution to solid film via the spin-coating deposition process. Image by KAUST

Solar cell performance and stability depend on the morphology of the thin films, especially their ability to crystallize in the so-called photoactive α-phase. Perovskites that contain lead tend to combine various halides, such as the anionic forms of bromine and iodine, with mixtures of methylammonium, formamidinium, cesium and other cations. These have led to record conversion efficiencies and thermal stabilities compared with their single-halide, single-cation analogs. However, these mixed-halide, mixed-cation perovskite films have been characterized only through ex-situ postdeposition techniques. This limits the understanding of the mechanisms that govern their growth from their sol-gel precursor to their solid state and stalls attempts to improve device performance and stability.

Researchers from the Australian National University (ANU) have reportedly broken new ground in solar cell energy efficiency and in the process provided a glimpse of the technology’s future. The researchers have a announced a record of 21.6% efficiency, which they say is the highest achieved for perovskite cells above a certain size.

Associate Professor Thomas White says as a comparison, typical solar panels being installed on rooftops right now have efficiencies of 17-18%. “There are three things you’re trying to achieve with solar cells, you’re trying to make them efficient, stable and cheap," he said. "Perovskites are the future of solar cells."

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have created a nickel oxide material that shows signs of superconductivity.

Also known as a nickelate, it’s the first in a potential new family of unconventional superconductors that’s very similar to the copper oxides, or cuprates, whose discovery in 1986 raised hopes that superconductors could someday operate at close to room temperature and revolutionize electronic devices, power transmission and other technologies. Those similarities make scientists wonder if nickelates could also superconduct at relatively high temperatures.

Researchers led by Prof. MA Cheng from the University of Science and Technology of China (USTC) have proposed a perovskite-based strategy to address the electrode-electrolyte contact issue that is limiting the development of next-generation solid-state Li batteries. The solid-solid composite electrode created this way reportedly exhibited exceptional capacities and rate performances.

Replacing the organic liquid electrolyte in conventional Li-ion batteries with solid electrolytes can greatly alleviate the safety issues, and potentially break the "glass ceiling" for energy density improvement. However, mainstream electrode materials are also solids. Since the contact between two solids is nearly impossible to be as tight as that between solid and liquid, at present the batteries based on solid electrolytes typically exhibit poor electrode-electrolyte contact and unsatisfactory full-cell performances.