In two research papers published in the prestigious journals Joule and PNAS (Proceedings of the National Academy of Sciences), an international research team led by Monash University has developed a highly efficient, ultra-thin photovoltaic cell with the highest mechanical bending and stretching capabilities, as well as the ability to provide sustained power.
In their paper, Joule researchers successfully developed a novel mechanically robust light-absorbing material that can be used to fabricate ultra-flexible solar cells. These cells achieve a power conversion efficiency of 13%, retain 97% efficiency after 1000 bending cycles, and retain 89% efficiency after 1000 stretching cycles.
Dr. Wenchao Huang, a researcher in the Department of Materials Science and Engineering at Monash University, explained that power conversion efficiency takes into account how much solar energy can be converted into electrical energy. The amount of solar energy irradiated on Earth is 1000 watts per square meter. Our device can generate 130 watts of electrical energy per square meter. The 13% efficiency we achieved is one of the highest efficiencies among organic solar cells.
In a PNAS paper, tests showed that after treating the solar cell with a special method, its performance decreased by only 4.8% after an astonishing 4,736 hours. It can operate for more than 20,000 hours (about 2.5 years) with minimal degradation, and its estimated shelf life is 11.5 years.
The solar cell has an area of only 2 square centimeters, roughly the same as the 5c in Australia, and is light enough to be supported by a flower petal, producing 9.9 watts of power per gram.
Further testing has shown that this revolutionary device could serve as a battery alternative in many future technologies, such as mobile phones, watches, the Internet of Things (IoT), and biosensors.
Researchers at RIKEN in Japan, in collaboration with colleagues from the University of Tokyo, the University of California, the Australian Synchrotron Radiation Facility, and Monash University, led these studies. The researchers are working to commercialize the technology.
Researchers have developed new materials and a simple post-annealing method to improve the mechanical and environmental stability of organic photovoltaics without reducing efficiency, thereby enhancing stability and scalability, according to the Micro Lithium Battery Group. Annealing is a heat treatment that alters the physical (and sometimes chemical) properties of a material to reduce its degradation. These solar cells were fabricated and tested in laboratories in Japan using advanced thin-film deposition and characterization equipment. Some key parts of this research on device physics were conducted at Monash University's Renewable Energy Laboratory and the Australian Synchrotron.
Despite its small size, the micro-lithium battery group's analysis suggests that the low cost of this ultra-thin photovoltaic cell allows for easy replication via continuous printing technology, making it ideal for rapid tracking and mass production in wearable technology.
