The new ultrathin material has the potential to significantly increase the efficiency of solar panels. Colorado State University reports.
Most modern solar panels are made of silicon semiconductors. They have a significant “innate” minus – about 40% of the light falling on them turns into heat and does not participate in the generation of electricity.
A group of scientists led by Rachel Austin proposed creating solar cells based not on silicon, but on its close analogue, molybdenum disulfide. The idea arose when experimenting with an ultrafast transient absorption spectrometer that can very accurately measure the successive energy states of individual electrons when excited by a laser pulse. Experiments using this instrument can provide “pictures” of how charges flow in a system. The authors created a photoelectrochemical cell using a monolayer of molybdenum disulfide, then excited electrons with a laser and tracked their movement through the material.
This material turned out to be extremely efficient at converting light into energy. Additionally, they were able to find out exactly why this happened.
This is because its crystal structure allows it to extract and use the energy of so-called hot electrons, which are high-energy electrons that are briefly excited from their ground state when they collide with visible light. In the new photoelectrochemical cell, the energy of these hot electrons is instantly converted into current instead of wasted as heat. The observed “use” phenomenon of hot electrons is absent in conventional silicon solar cells.
The authors hope that in the future, based on this technology, it will be possible to create efficient photovoltaic panels with twice the efficiency of modern ones.
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