University of Toledo team reports breakthrough in new material for all perovskite tandem solar cells

Researchers from the University of Toledo have reported progress that may push the performance of tandem perovskite solar cells to new levels. Working in collaboration with the U.S. Department of Energy's National Renewable Energy Lab and the University of Colorado, Dr. Yanfa Yan, UToledo professor of physics, envisions that the new high efficiency tandem perovskite solar cell will be ready to debut in full-sized solar panels in the consumer market in the near future.

"We are producing higher-efficiency, lower-cost solar cells that show great promise to help solve the world energy crisis," Yan said. "The meaningful work will help protect our planet for our children and future generations. We have a problem consuming most of the fossil energies right now, and our collaborative team is focused on refining our innovative way to clean up the mess."

Eindhoven team finds that the addition of fluoride boosts the stability of perovskite solar cells

Researchers at the Eindhoven University of Technology in the Netherlands have found a way to address the issue of stability in perovskite solar cells by adding a small amount of fluoride during the production process, which was found to increase the stability of such cells.

Fluoride stabilizes perovskite solar cells imageFluoride stablizes perovskite solar cells by encouraging the formation of strong hydrogen bonds and ionic bonds on the surface of the perovskite material.

The scientists found the fluoride ions form a protective layer around perovskite crystals, preventing the ill effects of light, heat and moisture. "Our work has improved the stability of perovskite solar cells considerably," said Shuxia Tao, assistant professor at Eindhoven University of Technology's Center for Computational Energy Research. "Our cells maintain 90% of their efficiency after 1,000 hours under extreme light and heat conditions. This is many times as long as traditional perovskite compounds. We achieve an efficiency of 21.3%, which is a very good starting point for further efficiency gains."

UK researchers achieve record PSC stability using waterproof graphite-based coating

Researchers at the University of Bath have applied a waterproof graphite-based coating to a perovskite cell intended to power the production of hydrogen underwater. The cell reportedly worked underwater longer than expected, and may open the door to a cheap and sustainable way of making hydrogen fuel from water using sunlight.

Researchers used graphite film to coat perovskite solar cells and waterproof them image

“The coated cells worked underwater for 30 hours – ten hours longer than the previous record,” the scientists wrote, adding the glue sandwiching the coat to the cells began to fail after 30 hours. They believe stronger glue could help the cell stabilize for longer. “We achieve a record stability of 30h in aqueous electrolyte under constant simulated solar illumination, with currents above 2 mA cm−2 (milliamperes per cm−2) at 1.23 VRHE,” they added.

Interview with Greatcell Solar Materials' GM Yanek Hebting

In December 2018, Greatcell Solar declared bankruptcy, a sad ending to a once promising perovskite venture. However, prior to this bankruptcy (in September 2018), the Production Division of Greatcell Solar was sold off, in a new business called Greatcell Solar Materials (GSM).

GSM's materials image

GSM manufactures and supplies its products like perovskite precursors, silver inks, various dopants and more to the scientific community. The company's general manager, Dr. Yanek Hebting, kindly agreed to answer some of our questions regarding GSM's business and technology.

Researchers develop artificial retinas with microcavity perovskite photoreceptors

Researchers at the National Tsing Hua University in Taiwan, led by Professor Hao-Wu Lin, have demonstrated that high-performance filter-less artificial human photoreceptors can be realized by integrating a novel optical metal/dielectric/metal microcavity structure with vacuum-deposited perovskite photoresponse devices.

Schematic and cross-sectional SEM image of the photoreceptor with an inverted structure image

Sensory substitution with flexible electronics is one of the intriguing fields of research. Scientists already fabricate electronic devices that can replicate, to a certain degree degree, some of the human senses – touch (electronic skin – e-skin), smell (e-nose), and taste (e-tongue). E-versions of the eye's photoreceptors (e-retinas) could potentially be used in a wide range of applications from robotic humanoid vision to artificial retina implantation for vision restoration or even vision extension into a wider range of wavelength.

HZB team opens the door to stable PSCs based on inorganic perovskite thin films

A team at the Helmholtz-Zentrum Berlin (HZB) has succeeded in producing inorganic perovskite thin films at moderate temperatures using co-evaporation – rendering the process of post-tempering at high temperatures unnecessary it much easier to produce thin-film solar cells.

HZB team opens the door to stable PSCs based on inorganic perovskite thin films imageBy co-evaporation of cesium iodide and lead iodide thin layers of CsPbI3 can be produced even at moderate temperatures. An excess of cesium leads to stable perovskite phases. image: HZB

Researchers all over the world are working intensively on the development of perovskite solar cells. The focus is mainly on ones made from metal-organic hybrid perovskites, whose crystal structure is composed of inorganic elements such as lead and iodine as well as an organic molecule. Completely inorganic perovskite semiconductors such as CsPbI3 have the same crystalline structure as hybrid perovskites, but contain an alkali metal such as caesium instead of an organic molecule. This makes them much more stable than hybrid perovskites, but usually requires an extra production step at very high temperature – several hundred degrees Celsius.

Caffeine can make perovskite solar cells more stable under heat

Researchers at the California NanoSystems Institute at UCLA have discovered that caffeine improves the thermal stability of perovskite solar cells.

“Solar cells need high thermal stability since they are constantly exposed to sunlight, which warms up the devices,” said Yang, who is also a professor of materials science and engineering at the UCLA Samueli School of Engineering. “While perovskites are an attractive option for solar cells, the materials degrade and become less stable over time. We need them to last 20 to 30 years like traditional solar cells.”