A team of scientists say they've flipped the script when it comes to how silicon interacts with light.
The UC Irvine-led team's innovative tech facilitates ultrathin silicon solar cells that could power thermoelectric clothing or onboard vehicle and device charging, per a news release.
The journal ACS Nano published the study, which was conducted in collaboration with scientists from Kazan Federal University in Russia and Tel Aviv University.
The key for the team was not to change the silicon material itself, but instead focus on conditioning the light to change pure silicon from an indirect to a direct bandgap semiconductor.
As an indirect bandgap semiconductor, silicon's "optical properties are inherently weak," commented Dmitry Fishman, the study's lead author. The team used a method to enhance the momentum of photons.
"Photons carry energy but almost no momentum, but if we change this narrative explained in textbooks and somehow give photons momentum, we can excite electrons without needing additional particles," study co-author Eric Potma said.
The result of the added momentum was majorly enhanced light absorption and a huge increase in device performance. Potma divulged the method "increases light absorption by a factor of 10,000, completely transforming light-matter interaction."
Potma says that innovation is much-needed for solar energy to become a viable clean energy source and slow the warming of the planet that is coming with increasingly dire consequences.
Advocates of dirty energy sources like coal and gas often point to the cost and deficiencies of current solar tech in arguments against adoption. While this view is at odds with all the progress being made, that doesn't mean solar can't take further strides.
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"The commercial solar cells we rely on are falling short," Potma said.
The research team's work is part of many efforts to increase the efficiency of solar energy, lower costs, optimize silicon, and explore alternatives for cells.
Some of the current efforts include coating silicon and perovskite, enhancing tandem solar panels, fashioning organic semiconductors, maximizing Kesterite thin-film solar cells, and going all-in on perovskite as the primary material for solar cells.
Scientists at MIT are also at work on paper-thin solar cells, as are researchers in Spain. Ultimately, the hope for thinner cells is to add more practical solutions for solar energy in applications like wearables, and on-board vehicle charging.
The UC-Irvine team was bullish that their findings could play a big role in maximizing solar energy by improving silicon's light absorption.
Potma pointed out the current thickness of silicon solar cells "not only drives up production costs but also limits efficiency due to increased charge carrier recombination."
"The thin-film solar cells that are one step closer to reality due to our research are widely seen as the solution to these challenges," concluded Potma.
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