Better Solar Energy Systems: More Heat, More Light
Solar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but __1__ now they havent been very good at the heat-generating part compared to a stand-alone solar thermal collector. Thats because they operate at low temperatures to cool crystalline silicon solar cells, which lets the silicon generate more __2__ but isnt a very efficient way to gather heat.
Thats a problem of __3_ . Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower __4__. 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 __5__ 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 Queens University, Canada.
Most solar panels are made with crystalline silicon，but you can also make solar cells out of amorphous silicon, __6__ known as thin-film silicon. They dont create as much electricity, but they are lighter, flexible, and cheaper. And, because they __7__ much less silicon, they have a greener footprint. Unfortunately，thin-film silicon solar cells are __8__ to some bad-news physics in the form of the Staebler-Wronski effect.
That means that their efficiency __9__ when you expose them to light pretty much the worst possible effect for a solar cell, Pearce explains，which is one of the __10__ 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 __11__ of PVT. You dont have to cool down thin-film silicon to make it work. In fact，Pearces group discovered that by heating it to solar-thermal operating temperatures，near the boiling __12__ of water, they could make thicker cells that largely __13__ the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy __14__ , they also found that by baking the cell once a day，they __15__ the solar cells electrical efficiency by over 10 percent. 词汇:
photovoltaic n.光电的
silicon n.硅
thermal adj.热的，热量的
amorphous adj.非晶形的
crystalline adj.晶体的
footprint n.足迹
注释：
1. solar photovoltaic thermal energy systems:太阳能光伏热能系统
2. they: 指代 solar photovoltaic thermal energy systems。
3. stand-alone:单机的
4. crystalline silicon solar cells:晶体硅太阳能电池
5. which:指前半句中的 to cool crystalline silicon solar cells 这件事
6. room:空间
7. solar panels:太阳能电池板
8. amorphous silicon：非晶硅
9. thin-film silicon:薄膜硅
10. Staebler-Wronski Effect: SWE效应。在光的照射下，非晶桂氢的导电性短时间内显著衰退，这种特性被称为SWE效应o
11. pretty much:几乎
12. the worst possible effect：最可能坏的效应
13. engineer around:精心地设计以克服或绕过
14. solar-thermal operating temperatures:太阳热能操作温度