近日，一種最有前途的制作廉價(jià)且效率可觀的光伏電池技術(shù)再一次走上了降價(jià)之路。在加拿大多倫多大學(xué)的科學(xué)家們發(fā)現(xiàn)，便宜的鎳在關(guān)鍵的電接觸上面可以像黃金一樣通過(guò)其太陽(yáng)能電池的膠體量子點(diǎn)收集的電流。

然而，Professor Ted Sargent''''s group的光伏研究項(xiàng)目負(fù)責(zé)人Lukasz Brzozowski說(shuō)，使用的鎳的改變又可以降低原本就很便宜的材料費(fèi)用的40%-80%。在2010年7月12日，美國(guó)物理協(xié)會(huì)（AIP）出版發(fā)行了他們目前的研究-應(yīng)用物理快報(bào)（Applied Physics Letters）。

量子點(diǎn)是一種半導(dǎo)體材料，其使用成本低，在液體溶液中能夠產(chǎn)生高流動(dòng)性的化學(xué)反應(yīng)。由于大小不同，量子點(diǎn)的性質(zhì)也會(huì)變化，量子點(diǎn)可配合照明光譜。

例如，一半的陽(yáng)光都在紅外波段，而其中大部分是不能以硅為基礎(chǔ)的太陽(yáng)能電池收集。Sargent團(tuán)隊(duì)率先開(kāi)發(fā)和設(shè)計(jì)了量子點(diǎn)太陽(yáng)能電池收集可見(jiàn)光和紅外光。他們的電力轉(zhuǎn)換效率高達(dá)5%,而其目標(biāo)是在商業(yè)化之前達(dá)到10%。

事實(shí)上，起初，鎳并沒(méi)有用在此項(xiàng)目中。后來(lái),在鎳之間添加一納米的氟化鋰,量子點(diǎn)就制造出了一個(gè)屏障來(lái),阻止其受污染，最后電池效率就達(dá)到了預(yù)期水平. 這次加拿大研究人員的發(fā)現(xiàn)意味著最近太陽(yáng)能電池的里程碑。

New Inexpensive Solar Cell Design

One of the most promising technologies for making inexpensive but reasonably efficient solar photovoltaic cells just got much cheaper. Scientists at the University of Toronto in Canada have shown that inexpensive nickel can work just as well as gold for one of the critical electrical contacts that gather the electrical current produced by their colloidal quantum dot solar cells.

The change to nickel can reduce the cell''''s already low material costs by 40 to 80 percent, says Lukasz Brzozowski, the director of the Photovoltaics Research Program in Professor Ted Sargent''''s group. They present their research in the July 12, 2010 issue of Applied Physics Letters, which is published by the American Institute of Physics (AIP).

Quantum dots are nanoscale bits of a semiconductor material that are created using low-cost, high-throughput chemical reactions in liquid solutions. Since their properties vary according to their size, quantum dots can be made to match the illumination spectrum.

Half of all sunlight, for example, is in the infrared wavelengths, most of which cannot be collected by silicon-based solar cells. Sargent''''s group has pioneered the design and development of quantum dot solar cells that gather both visible and infrared light. They have reached a power-conversion efficiency as high as 5 percent and aim to improve that to 10 percent before commercialization.

At first, nickel did not appear to do the job. Adding just one nanometer of lithium fluoride between the nickel and the dots created a barrier that stopped the contamination, and the cell''''s efficiency jumped back up to the expected level.

This is the latest of several recent solar-cell milestones by the Canadian researchers. "We have been able to increase dramatically the efficiency of our photovoltaics over the last several years and continue to hold the performance world records," Professor Sargent said.