SYDNEY, Oct. 7 (Xinhua) -- An Australian-led team has set a global record by creating the largest and most efficient triple-junction perovskite-perovskite-silicon tandem solar cell reported to date, marking a key step toward stabilizing next-generation renewable energy technology.
The team's 16-square-centimeter cell achieved an independently certified steady-state power conversion efficiency of 23.3 percent, the highest reported for a large-area device of this kind, according to a statement released on Tuesday by the University of Sydney, which led the study.
At the smaller scale, a 1-square-centimeter cell recorded 27.06 percent efficiency and set new standards for thermal stability. It passed the International Electrotechnical Commission's Thermal Cycling test with minimal degradation, the statement said.
This cell retained 95 percent of its efficiency after more than 400 hours of continuous operation under light in the test that exposes devices to 200 cycles of extreme temperature swings between -40 and 85 degrees Celsius, the statement added.
The study, published in the journal Nature Nanotechnology, demonstrates high efficiency and durability, important steps for overcoming barriers to the development of perovskite tandem solar cell technology.
A triple-junction solar cell uses three interconnected semiconductors, each absorbing a different part of the solar spectrum to maximize conversion of the sun's energy into electricity, researchers said.
This latest advance was achieved by re-engineering the perovskite chemistry and triple-junction cell design to improve the solar cells' performance and resilience, said Professor Anita Ho-Baillie from the University of Sydney Nano Institute and School of Physics, who led the study.
The researchers replaced less stable methylammonium, commonly used in high-efficiency perovskite cells, with rubidium creating a perovskite lattice that is less prone to defects and degradation. They also replaced the less stable lithium fluoride with piperazinium dichloride for a new surface treatment.
To connect the two perovskite junctions, the researchers used gold at the nanoscale and, using advanced transmission electron microscopy, clarified that gold at this scale is in the form of nanoparticles, not as a continuous film as many perceived. The team used this knowledge to engineer gold nanoparticle coverage to maximize the flow of electric charge and light absorption by the solar cell. ■
