Looking for a way to make solar panels more efficient? Why not try putting a dent in them? No, it’s not a “fix the TV by banging your hand on it” solution, but an actually demonstrable discovery from researchers at the United Kingdom’s University of Warwick.
This isn’t something you could do with your own home solar panel by way of a ladder and a hammer, though. Instead, the research shows that it’s possible to squeeze extra power out of solar cells by deforming the tiny p-type and n-type crystals in photovoltaic semiconductors.
Most commercial solar panels are made up of two layers, which create a junction at the boundary where the positively charged p-type and negatively-charged n-type semiconductors meet. When the solar cell absorbs light, this junction splits the photo-excited carriers in opposite directions, thereby generating current and voltage. But while this junction is crucial for producing electricity, it also comes with a limit — called the Shockley-Queisser limit — which stops any more than 33.7 percent of the power in sunlight being transformed into electricity.
For their demonstration, the Warwick researchers used conductive tips to force semiconductors into a device called a nano-indenter, which deformed the individual crystals. By making the semiconductors non-symmetrical, they were able to create something called the “bulk photovoltaic effect,” another way to collect charge. Combining these two approaches resulted in improved efficiency of solar cells and the chance to generate more electrical energy from sunlight.
“This flexo-photovoltaic effect is a new effect,” Marin Alexe, a professor in the Department of Physics at Warwick, told Digital Trends. “It shows that by engineering the strain applied, any semiconductor can be transformed in a photovoltaic generator without a need [for] chemical doping or any other processing. We haven’t yet evaluated in detail how effective is this effect. But in principle there is nothing to prevent combining the two effects, the classical harvesting using p-n junctions and the present flexo-PV effect.”
So what’s next for the research? And, more importantly, when will be able to lay our hands on these more efficient solar cells? “Next, we would like to understand the microscopic mechanism of this intriguing bulk photovoltaic effect, which stays as the basis of the flexo-PV effect,” Alexe continued. “Then we will look to quantify the gain and efficiency at both macro and nano-scale.”
Alexe acknowledged that this could be the start of a “long and painful optimization and engineering process.” However, the team has filed a patent application to lay claim to their work. Now they just need to find some industrial partners to further develop their ideas.
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