单选题：根据以下资料，回答题。Better Solar Energy Systems: More Heat, More Lig

根据以下资料，回答题。 Better Solar Energy Systems: More Heat, More Light Solar photovoltaic thermal energy systems, or PVTs, generate 51 heat and electricity, but until now they haven’t been very good at the heat-generating part 52 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 53 .
That’s a problem of economics. 54 solar hot-water systems can harvest much more energy 55 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 56 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, but you can also make 57 cells out of amorphous silicon, commonly known 58 thin-film silicon. They don’t create as 59 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 60 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 61 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 62 of water, they could make thicker cells that largely 63 the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy 64 , they also found that by baking the cell once a day, they 65 the solar cell’s electrical efficiency by over 10 percent.
请在第_____处填上正确答案。 A．both
B．also
C．between
D．all