24小时热门版块排行榜

返回列表

lcazzapple

木虫 (正式写手)

应助: 3 (幼儿园)
金币: 2088.6
散金: 100
红花: 4
帖子: 722
在线: 205.2小时
虫号: 265685
注册: 2006-07-15
性别: GG
专业: 生物化学

[交流] 【讨论】光电转换率最高可达100% 新型太阳能电池研发成功。这消息真的假的？？已有30人参与

加州理工学院近日研发出了一种新的太阳能电池，其基本原理是将细长的硅线阵列嵌入聚合物基板中。除了纤薄可弯曲外，它对太阳光的吸收和光电转换效率方面都取得了极大地突破。此外，和传统太阳能电池所需要的昂贵的半导体材料量相比，这种新型太阳能电池仅需要一小部分。

应用物理学及材料学教授Harry Atwater和Howard Hughes表示：“这些太阳能电池首次突破了传统的吸光材料的光捕获极限。”新型太阳能电池所采用的硅线阵列对单一波长的入射光的吸收率高达96%，对全波长阳光的捕获率可达85%。

Atwater指出：“许多材料对光线的捕获能力很好，但是却无法转换成电能，比如黑涂料。对于太阳能电池来说，吸收的光子能否转换为电荷载子（charge carrier）也非常重要。”而他们研发的硅线阵列太阳能电池则可以将所吸收光子的90%至100%转换为电子。从技术上讲，这种阵列拥有几近完美的内部量子效率（internal quantum efficiency）。

Atwater总结说：“对光的高吸收率和较好的转换能力成就了这种太阳能电池的高质量。”

硅线阵列中的硅线长度在30至100微米（micron）之间，直径仅为1微米。整个阵列的厚度相当于硅线的长度，但是从面积或体积角度来看，这种材料中只有2%才是硅，其它98%都是聚合物。由于硅是传统太阳能电池中一种很昂贵的成分，所以这种只需要传统所需量1/50的太阳能电池投产的成本将低很多。

===================================================
High-efficiency solar cells
19 February 2010

Using arrays of long, thin silicon wires embedded in a polymer substrate, a team of scientists from the California Institute of Technology (Caltech) has created a new type of flexible solar cell that efficiently converts photons into electrons.

‘These solar cells have, for the first time, surpassed the conventional light-trapping limit for absorbing materials,’ said Harry Atwater, Howard Hughes professor of applied physics and materials science at Caltech.

The light-trapping limit of a material refers to how much sunlight it is able to absorb.

The silicon-wire arrays absorb up to 96 per cent of incident sunlight at a single wavelength and 85 per cent of total collectible sunlight.

The silicon-wire arrays are able to convert between 90 and 100 per cent of the photons they absorb into electrons.

The key to the success of the solar cells is their silicon wires, each of which, said Atwater, are independent highly efficient and high-quality solar cells.

When brought together in an array, however, they’re even more effective, because they interact to increase the cell’s ability to absorb light.

Light comes into each wire and a portion is absorbed and another portion scatters.

The collective scattering interactions between the wires make the array very absorbing.

This effect occurs despite the sparseness of the wires in the array - they cover only between two to 10 per cent of the cell’s surface area.

The new solar cells also use only a fraction of the expensive semiconductor materials required by conventional solar cells.

Just two per cent of the cell is silicon, while 98 per cent is polymer.

Since the silicon material is an expensive component of a conventional solar cell, a cell that requires just two per cent of the amount of semiconductor material will be much cheaper to produce.

The composite nature of these solar cells, Atwater added, means that they are also flexible. ‘Because flexible thin films can be manufactured in a roll-to-roll process, it is an inherently lower-cost process than one that involves brittle wafers like those used to make conventional solar cells,’ he said.

The next steps, Atwater said, are to increase the operating voltage and the overall size of the solar cell. ‘The structures we’ve made are square centimetres in size,’ he explained. ‘We’re now scaling up to make cells that will be hundreds of square centimetres - the size of a normal cell.’

Atwater says that the team is already ’on its way’ to showing that large-area cells work just as well as these smaller versions.

===================================================

该课题组发表在Science上的最新文章
Science 8 January 2010:
Vol. 327. no. 5962, pp. 185 - 187
DOI: 10.1126/science.1180783

Energy-Conversion Properties of Vapor-Liquid-Solid–Grown Silicon Wire-Array Photocathodes

Shannon W. Boettcher, Joshua M. Spurgeon, Morgan C. Putnam, Emily L. Warren, Daniel B. Turner-Evans, Michael D. Kelzenberg, James R. Maiolo, Harry A. Atwater,* Nathan S. Lewis*

该课题组发表在Nature Material上的最新文章
Nature Materials 9, 239 - 244 (2010)
Published online: 14 February 2010 | Corrected online: 19 February 2010 | doi:10.1038/nmat2635

Enhanced absorption and carrier collection in Si wire arrays for photovoltaic applications
Michael D. Kelzenberg1, Shannon W. Boettcher1, Jan A. Petykiewicz1, Daniel B. Turner-Evans1, Morgan C. Putnam1, Emily L. Warren1, Joshua M. Spurgeon1, Ryan M. Briggs1, Nathan S. Lewis1 & Harry A. Atwater1

[ Last edited by lcazzapple on 2010-3-3 at 12:39 ]

回复此楼