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Breakthrough in low-cost efficient solar cells

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April 8, 2010

Breakthrough in low-cost efficient, dye-sensitized solar cells

Breakthrough in low-cost efficient, dye-sensitized solar cells

The Earth receives more solar energy in one hour than the human race currently consumes in a year. At least, that’s what the scientists at Canada’s Université du Québec à Montréal (UQAM) tell us. That’s a lot of energy, and it’s going mostly untapped. Why? Because, we are told, solar collection cells are too inefficient and expensive to be more widely used. A researcher at UQAM, however, has come up with new technology that addresses these problems - for the first time in 20 years, according to Professor Benoît Marsan, there is an effective, low-cost solar cell.

The conventional solar cell

Marsan’s invention builds upon work done in the early '90s by Professor Michael Graetzel of the Ecole Polytechnique Federale de Lausanne in Switzerland. Graetzel designed the dye-sensitized solar cell, which is still considered to be one of the most promising types of solar collection technology. Graetzel’s cell is composed of a porous layer of titanium dioxide nanoparticles, covered with a molecular dye that absorbs sunlight, like the chlorophyll in green leaves. The titanium dioxide is immersed under an electrolyte solution, above which is a platinum-based catalyst.

As in a conventional alkaline battery, an anode (the titanium dioxide) and a cathode (the platinum) are placed on either side of a liquid conductor (the electrolyte). Sunlight passes through the cathode and the conductor, and then withdraws electrons from the anode, at the bottom of the cell. These electrons travel through a wire from the anode to the cathode, creating an electrical current.

The drawbacks

Although Graetzel’s cell is easy to manufacture and can be used in a variety of applications, Marsan says it has two major problems that have held it back from large-scale commercialization. For one thing, the electrolyte is extremely corrosive, resulting in a lack of durability, and it’s densely colored, preventing the efficient passage of light. The other problem is the platinum cathode. Platinum is expensive, non-transparent, and rare - hardly a low-budget substance.

The electrochemical cell

Marsan’s patented electrochemical solar cell has neither of these problems. For the electrolyte, UQAM created a new liquid/gel that is transparent and non-corrosive, increasing the cell’s output and stability. For the cathode, the platinum has been replaced with much less expensive cobalt sulphide. This substance is also more efficient, more stable, and easier to produce in a lab.

Using this approach, the researchers have demonstrated an efficiency of 6.4% under standard illumination test conditions. While this is lower than the efficiency of conventional PV cells, the manufacturing and durability advantages of the Marsan electrochemical solar cell still make it an attractive proposition.

Marsan’s findings have recently been published in the Journal of the American Chemical Society and Nature Chemistry.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
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5 Comments

Hmm, this article is a little misleading. 6.4% is hardly what I would consider efficient. Current cell tech is what? 18%? I suppose the cost per percentage of efficiency is probably better, but doesn't this just mean that these cells will take up more space to generate the same amount of power as conventional PV cells? I think this is a fine achievement, but the article makes it seem like a 40% efficiency or something close was achieved.

Stradric
8th April, 2010 @ 06:52 pm PDT

Wow- this is really interesting but- could you break it down for a person that is not aware of all the science terms you used- what is the bottom line...

Facebook User
9th April, 2010 @ 03:44 pm PDT

Sounds interesting.

There is a misnomer that SOLAR ENERGY IS FREE.

Infact one criticism on Solar PV (Photovoltaics) is that ,the amount of energy that goes into its production one may not get back in its life time. The material that goes into the production of glass,aluminium,copper etc., is all energy intensive(to make).

As such any improvement in efficiency and cost reduction is most welcome.

Dr.A.Jagadeesh Nellore(AP),India

Anumakonda Jagadeesh
9th April, 2010 @ 08:39 pm PDT

"Infact one criticism on Solar PV (Photovoltaics) is that ,the amount of energy that goes into its production one may not get back in its life time."

This has been discredited as a myth.

http://www.nrel.gov/docs/fy04osti/35489.pdf

excerpt: "Based on models and real data, the idea that PV cannot pay back

its energy investment is simply a myth. Indeed, researchers Dones

and Frischknecht found that PV-systems fabrication and fossilfuel

energy production have similar energy payback periods

(including costs for mining, transportation, refining, and

construction)."

Mark in MI
12th April, 2010 @ 12:52 pm PDT

" Infact one criticism on Solar PV (Photovoltaics) is that ,the amount of energy that goes into its production one may not get back in its life time"

This claim is utterly false. It was true at one point in time, the 1970s, but since then the energy cost of semiconductor fabrication has plummeted, and the efficiency of the cells has skyrocketted. Energy payoff for a typical modern panel is around two years.

By the way, the explanation of how these cells work is completely wrong in the article. For a real description, see the wiki article.

Maury

Maury Markowitz
10th June, 2010 @ 04:11 am PDT
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