From the Science Daily--solar topics

Absorbing more of the spectrum

Using OLED technology for solar power.

“We’re working on synthesizing novel polymers with variable band gaps, including high, medium and low-band gap varieties, to absorb the full spectrum of sunlight. By this we can double the light harvesting or absorption,” Qiao said.


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Roads as water heaters/solar energy creators:

“Asphalt has a lot of advantages as a solar collector,” Mallick says. “For one, blacktop stays hot and could continue to generate energy after the sun goes down, unlike traditional solar-electric cells. In addition, there is already a massive acreage of installed roads and parking lots that could be retrofitted for energy generation, so there is no need to find additional land for solar farms. Roads and lots are typically resurfaced every 10 to 12 years and the retrofit could be built into that cycle. Extracting heat from asphalt could cool it, reducing the urban ‘heat island’ effect. Finally, unlike roof-top solar arrays, which some find unattractive, the solar collectors in roads and parking lots would be invisible.”

Hot water flowing from an asphalt energy system could be used “as is” for heating buildings or in industrial processes, or could be passed through a thermoelectric generator to produce electricity.

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Slicing Wafer better lowers costs of solar cells.

"We're coming up with a more efficient way of making germanium wafers for solar cells – to reduce the cost and weight of these solar cells and make them defect-free."

The new method for slicing solar cell wafers – known as wire electrical discharge machining (WEDM) – wastes less germanium and produces more wafers by cutting even thinner wafers with less waste and cracking. The method uses an extremely thin molybdenum wire with an electrical current running through it. It has been used previously for machining metals during tool-making.

Germanium serves as the bottom layer of the most efficient existing type of solar cell, but is used primarily on NASA, military and commercial satellites because of the high expense – raw germanium costs about $680 per pound. Four-inch-wide wafers used in solar cells cost $80 to $100 each, and the new cutting method may reduce the cost by more than 10 percent, . . .

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Old news here
Thin films solar cells

Silicon is the material of choice in the electronics industry because of its stability, non-toxicity and ubiquity. However, silicon is a poor absorber of light. In a bid to drive down costs, scientists have moved from using expensive thick silicon “wafers” to cheaper “thin film” cells, containing less silicon.


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