Two Swiss organizations have combined conventional silicon solar cells with an extra Perovskite layer – reaching a record 25.2% efficiency. This new addition can be easily introduced to extant assembly lines.
EPFL Polytechnique Institute has teamed up with CSEM research and technology organization from Neuchatel Sqizerland to successfully overcome previous engineering challenges – combining Silicon and Perovskites distinct spectral layers to circumvent previous efficiency records of silicon based convention.
Silicon based solar cells make up 90% of the solar energy market because they convert 20-22% of incoming light in to energy – placing them leaps and bounds ahead of competition. However they only convert red and infra-red layers of the EM spectrum.
Over the past nine years, Perovskite cells have improved by a factor of six. Not to mention Perovskite is more proficient at absorbing blue-green spectra. Scientists have been trying to combine these two so the resulting cell can absorb both red an green light, increasing the overall efficiency of the device.
The outside of silicon solar cells are made of really small pyramids 5 microns in size. The challenge was to somehow “glue” a perovskite layer over these tiny pyramids without damaging their electical conductivity – a consequence of this free flowing geometry.
Originally they attempted to simply paint liquid perovskite on. Unfortunately that lowered the conversion rate as it dried – homogenizing the surface geometry and ruining the integrity of the pyramid shape silicon layer.
Researchers circumvented this problem by meeting natural law half-way. They painted on a more porous inorganic material first so that most of the silicon cells pyramidal geometry was conserved in the porous membrane, then after that dries out they overlay the Perovskite.
Using this method they’ve broken previous conversion records reaching 25.2% efficiency.
“The calculations and work we have done show that a 30% efficiency should soon be possible,” say the study’s main authors Florent Sahli and Jérémie Werner.