A UT Austin chemist claims quantum dots can hit 66% efficiency in the conversion of light into electricity.
AUSTIN, Texas—Conventional solar cell efficiency could be increased from the current limit of 30 percent to more than 60 percent, suggests new research on semiconductor nanocrystals, or quantum dots, led by chemist Xiaoyang Zhu at The University of Texas at Austin.
Zhu and his colleagues report their results in this week's Science.
The scientists have discovered a method to capture the higher energy sunlight that is lost as heat in conventional solar cells.
The maximum efficiency of the silicon solar cell in use today is about 31 percent. That's because much of the energy from sunlight hitting a solar cell is too high to be turned into usable electricity. That energy, in the form of so-called "hot electrons," is lost as heat.
If the higher energy sunlight, or more specifically the hot electrons, could be captured, solar-to-electric power conversion efficiency could be increased theoretically to as high as 66 percent.
Photovoltaic cells of such a high efficiency would lower costs substantially. Some people are skeptical about the potential for cheap solar power. But my view is that while solar is still more expensive than wind, nuclear, coal, and other sources of electric power it will eventually become competitive. Its costs (though not always its market price) have steadily fallen for decades. First Solar continues to establish new lower cost points. Even potential for further cost cutting exists that solar should become cheap as a day time power source.
| Share | | Randall Parker, 2010 June 18 06:51 AM Energy Solar |
If more energy is captured instead of being turned into waste heat, it might make the panel more durable also.
Of course the big question is cost. But with 3 times the efficiency of the average commercial solar cell, this could cut the price per watt by a large percentage.
This would also make smaller areas more viable for solar power.
8 hour summer day, 40 degree latitude 600 Watts per sq. meter= 4.8 KW-Hours X 60%= 2.88 KW Hr per square meter.
The Nissan Leaf gets about 4 miles/KW Hr. It's size is 4.4 m X 1.8 m = 7.9 m2. Lets drop 30% for windows and we have about 5.5 m2. 5.5 m2 X 2.88 KW Hr/m2 X 4 miles/KW Hr = 63 miles per day solar range. While you are at work, your leaf could get a significant recharge from solar cells on the roof and hood.
I realize these numbers are overly optimistic, and neglect charging losses, but it is a demonstration that with higher efficiency solar, new applications are opened.