Scientists propose new recipes for perovskite cellOctober 24, 2018
Researchers from Kaunas University of Technology in Lithuania, working with the École Polytechnique Fédérale de Lausanne, have found an additive commonly used to improve performance in perovskite solar cells speeds up degradation of the material.
October 22, 2018 Mark Hutchins
While perovskites appear to be on the fast track to commercialization, concerns remain over the stability and durability of many of the materials used in them.
The new research, however, theorizes another reaction between TBP and perovskite semiconductor materials could be contributing to the sometimes rapidly declining performance seen in such cells.
“We have raised a hypothesis that tert-butylpyridine, which is a routinely used additive for improving performance, is reacting with semiconductors – i.e. hole transporting materials – in the solar cells,” says Professor Vytautas Getautis, from the KTU Faculty of Chemical Technology.
“Due to the reaction, the efficiency of the hole transporting material declines as the new pyridinated products are formed, and this has [a] negative influence on the performance of the cell.”
EPFL physicists were then able to confirm both the presence of the materials in aged perovskite solar cells, and prove their negative effect on performance.
However, the detection of the harmful substances after exploitation opens new avenues in the production of … long-term-stable perovskite solar cells,” adds Prof. Getautis.
KTU initially recommends using fewer pyridine-derivative materials in production, or changing the structure of the hole transport material to prevent the reaction taking place, as possible solutions.
At the MRS meeting, some researchers foreshadowed that day. Giles Eperon, a materials scientist at the University of Washington in Seattle, explained that when getting his Ph.D. at Oxford, he made a perovskite that strongly absorbs reddish light—the wavelengths that silicon has specialized in. Partnering with McGehee’s group, Eperon layered his red absorber on top of a more standard blue absorber, achieving an efficie…