新元素搭配将提高太阳能电池效率
文章来源:未知 文章作者:meng 发布时间:2010-09-09 01:08 字体: [ ]  进入论坛
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In what could be a step toward higher efficiency solar cells, an international team including University of Michigan professors has invalidated(使无效) the most commonly used model to explain the behavior of a unique class of materials called highly mismatched alloys2. Highly mismatched alloys, which are still in the experimental stages of development, are combinations of elements that won't naturally mix together using conventional(传统的,常见的) crystal growth techniques. Professor Rachel Goldman compares them to some extent to homogenized(均匀分布的) milk, in which the high-fat cream and low-fat milk that would naturally separate are forced to mix together at high pressure.

New mixing methods such as "molecular3 beam epitaxy(外延,外延附生) " are allowing researchers to combine disparate(不同的,全异的) elements. The results, Goldman says, are more dramatic than smooth milk.

"Highly mismatched alloys have very unusual properties," Goldman said. "You can add just a sprinkle(少量) of one element and drastically change the electrical and optical properties of the alloy1."

Goldman is a professor in the departments of Materials Science and Engineering, and Physics. Her team included other U-M physicists4 and engineers as well as researchers from Tyndall National Institute in Ireland.

Solar cells convert energy from the sun into electricity by absorbing light. However, different materials absorb light at different wavelengths5. The most efficient solar cells are made of multiple materials that together can capture a greater portion of the electromagnetic radiation in sunlight. The best solar cells today are still missing a material that can make use of a portion of the sun's infrared6 light.

Goldman's team made samples of gallium arsenide(砷化镓) nitride, a highly mismatched alloy that is spiked7 with nitrogen, which can tap into that underutilized(未充分使用的) infrared radiation.

The researchers used molecular beam epitaxy to coax8 the nitrogen to mix with their other elements. Molecular beam epitaxy involves vaporizing pure samples of the mismatched elements and combining them in a vacuum.

Next, the researchers measured the alloy's ability to convert heat into electricity. They wanted to determine whether its 10 parts per million of nitrogen were distributed as individual atoms or as clusters. They found that in some cases, the nitrogen atoms had grouped together, contrary to what the prevailing9 "band anti-crossing" model predicted.

"We've shown experimentally that the band anti-crossing model is too simple to explain the electronic properties of highly mismatched alloys," Goldman said. "It does not quantitatively10 explain several of their extraordinary optical and electronic properties. Atomic clusters have a significant impact on the electronic properties of alloy films."

If researchers can learn to control the formation of these clusters, they could build materials that are more efficient at converting light and heat into electricity, Goldman said.

"The availability of higher efficiency thermoelectrics(热电的) would make it more practical to generate electricity from waste heat such as that produced in power plants and car engines," Goldman said.



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1 alloy fLryq     
n.合金,(金属的)成色
参考例句:
  • The company produces titanium alloy.该公司生产钛合金。
  • Bronze is an alloy of copper and tin.青铜是铜和锡的合金。
2 alloys a0554febd06fadac0b9b8f0ad597e74d     
n.合金( alloy的名词复数 )
参考例句:
  • This is essentially a development of thoria dispersion strengthened nickel alloys. 这基本上是用二氧化钍弥散强度化的镍基合金。 来自辞典例句
  • The lack of deep hardening in these alloys negates their use. 这些合金缺乏深层硬化能力使它们无法利用。 来自辞典例句
3 molecular mE9xh     
adj.分子的;克分子的
参考例句:
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
4 physicists 18316b43c980524885c1a898ed1528b1     
物理学家( physicist的名词复数 )
参考例句:
  • For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说,这是受挫折的一年。 来自英汉非文学 - 科技
  • Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。
5 wavelengths 55c7c1db2849f4af018e7824d42c3ff2     
n.波长( wavelength的名词复数 );具有相同的/不同的思路;合拍;不合拍
参考例句:
  • I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话,因为我们俩完全不对路。 来自《简明英汉词典》
  • Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句
6 infrared dx0yp     
adj./n.红外线(的)
参考例句:
  • Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
  • Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。
7 spiked 5fab019f3e0b17ceef04e9d1198b8619     
adj.有穗的;成锥形的;有尖顶的
参考例句:
  • The editor spiked the story. 编辑删去了这篇报道。 来自《简明英汉词典》
  • They wondered whether their drinks had been spiked. 他们有些疑惑自己的饮料里是否被偷偷搀了烈性酒。 来自辞典例句
8 coax Fqmz5     
v.哄诱,劝诱,用诱哄得到,诱取
参考例句:
  • I had to coax the information out of him.我得用好话套出他掌握的情况。
  • He tried to coax the secret from me.他试图哄骗我说出秘方。
9 prevailing E1ozF     
adj.盛行的;占优势的;主要的
参考例句:
  • She wears a fashionable hair style prevailing in the city.她的发型是这个城市流行的款式。
  • This reflects attitudes and values prevailing in society.这反映了社会上盛行的态度和价值观。
10 quantitatively 4b081280983d0e01c866e9065e0034b0     
adv.数量上
参考例句:
  • With the ease, radiation detectors can be used semi-quantitatively in the field. 使用射线探测器可以很方便地进行野外半定量测定。 来自辞典例句
  • In other words, you are to analyze them quantitatively and qualitatively. 换句话说,你们要对它们进行量和质的分析。 来自辞典例句
TAG标签: cells solar materials
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