Better Solar Energy Systems: More Heat, More Light
Solar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but_until_ now they haven’t been very good at the heat-generating part compared to a stand-alone solar thermal collector. That’s because they operate at low temperatures to cool crystalline silicon solar cells, which lets the silicon generate more _electricity__ but isn’t a very efficient way to gather heat.
That’s a problem of _economics_ . Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower __cost_. And it，s also a space problem：photovoltaic cells can take up all the space on the roof, leaving little room for thermal applications.
In a pair of studies, Joshua Pearce, an associate professor of materials science and engineering, has devised a _solution__ in the form of a better PVT made with a different kind of silicon. His research collaborators are Kunal Girotra from ThinSilicon in California and Michael Pathak and Stephen Harrison from Queen’s University, Canada."
Most solar panels are made with crystalline silicon， you can also make solar cells out ofbut amorphous silicon, _commonly__ known as thin-film silicon. They don’t create as much electricity, but they are lighter, flexible, and cheaper. And, because they __require__ much less silicon, they have a greener footprint. Unfortunately，thin-film silicon solar cells are _vulnerable_ to some bad-news physics in the form of the Staebler-Wronski effect.
“That means that their efficiency __drops__ when you expose them to light — pretty much the worst possible effect for a solar cell,” Pearce explains，which is one of the __reasons_ thin-film solar panels make up only a small fraction of the market.
However, Pearce and his team found a way to engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new _type_ of PVT. You don’t have to cool down thin-film silicon to make it work. In fact，Pearce’s group discovered that by heating it to solar-thermal operating temperatures，near the boiling _point_ of water, they could make thicker cells that largely _overcame_ the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy _collector_ , they also found that by baking the cell once a day，they _boosted_ the solar cell’s electrical efficiency by over 10 percent.
Solar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but_until_ now they haven’t been very good at the heat-generating part compared to a stand-alone solar thermal collector. That’s because they operate at low temperatures to cool crystalline silicon solar cells, which lets the silicon generate more _electricity__ but isn’t a very efficient way to gather heat.
That’s a problem of _economics_ . Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower __cost_. And it，s also a space problem：photovoltaic cells can take up all the space on the roof, leaving little room for thermal applications.
In a pair of studies, Joshua Pearce, an associate professor of materials science and engineering, has devised a _solution__ in the form of a better PVT made with a different kind of silicon. His research collaborators are Kunal Girotra from ThinSilicon in California and Michael Pathak and Stephen Harrison from Queen’s University, Canada."
Most solar panels are made with crystalline silicon， you can also make solar cells out ofbut amorphous silicon, _commonly__ known as thin-film silicon. They don’t create as much electricity, but they are lighter, flexible, and cheaper. And, because they __require__ much less silicon, they have a greener footprint. Unfortunately，thin-film silicon solar cells are _vulnerable_ to some bad-news physics in the form of the Staebler-Wronski effect.
“That means that their efficiency __drops__ when you expose them to light — pretty much the worst possible effect for a solar cell,” Pearce explains，which is one of the __reasons_ thin-film solar panels make up only a small fraction of the market.
However, Pearce and his team found a way to engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new _type_ of PVT. You don’t have to cool down thin-film silicon to make it work. In fact，Pearce’s group discovered that by heating it to solar-thermal operating temperatures，near the boiling _point_ of water, they could make thicker cells that largely _overcame_ the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy _collector_ , they also found that by baking the cell once a day，they _boosted_ the solar cell’s electrical efficiency by over 10 percent.