Researchers from Peking University have conducted an experiment which is said to have demonstrated large-area perovskite solar cells are more stable 35 km up than at ground level. The researchers tested the stability of the devices by sending them to an altitude of 35 km above the Inner Mongolia autonomous region of China using an high-altitude balloon.
The cells, which had an active area of 1 cm², were developed with a TiO2 mesoporous structure based on two mixed-cation perovskites, FA0.9Cs0.1PbI3 and FA0.81MA0.10Cs0.04PbI2.55Br0.40. “Moreover, different kinds of perovskite photoactive absorbers with and without UV filters were investigated”, the scientists said.
The researchers said the stability of the cells was not compromised as the two main stress factors for the technology – oxygen and humidity – barely exist in near space. They said the atmosphere at 35 km contains trace amounts of moisture and ozone, resulting in an AM0 solar spectrum with light intensity of 136.7 mW/cm². “This atmosphere also contains several high-energy particles and radiation – such as neutrons, electrons and gamma rays – originating from the galactic cosmic rays and solar flares,” they added.
The perovskite cell devices tested, according to the researchers, retained 95.19% of their initial power conversion efficiency during the test under AM0 illumination.
The scientists claim the experiment not only paves the way for spatial application of perovskite cells, but also casts more light on how future “conventional” solar cells of this kind may reach more stability.