New electrolyte for dye-based solar cells

Chemistry World ^ | 04 April 2010 | Simon Hadlington

[neverdem]

Researchers have moved a step closer to overcoming one of the key hurdles to developing low-cost solar cells based on dye-coated titanium dioxide.

Dye-sensitised solar cells (DSCs) were invented by Michael Grätzel and Brian O'Regan some 20 years ago, and consist of a thin film of titanium dioxide coated with a ruthenium-based dye, in contact with a redox electrolyte. 

Dye-based solar cells could offer a cheaper alternative to silicon-based photovoltaics

While dye-based systems are less efficient in converting solar energy than photovoltaic cells made from silicon, they are likely to become cheaper to manufacture and be more versatile in a number of applications, making them an attractive commercial prospect. 

When light energy enters the cell it ejects an electron from the dye, which enters the TiO₂ and diffuses to an electrode. The electrolyte then supplies electrons back to the dye to regenerate it. However, finding a suitable electrolyte has proven to be a significant challenge.

The most efficient electrolyte that has been found so far is based on an iodide/triiodide couple. However, this absorbs a proportion of potentially useful light and is corrosive to silver-based electrical contacts, causing difficulties in manufacturing a robust and long-lasting device. A number of iodide-free systems have been investigated, but the cells have significantly lower efficiency in converting light to electric power.

Now, a team led by Grätzel, who is at the Swiss Federal Institute of Technology in Lausanne, has demonstrated a new electrolyte based on a disulfide/thiolate redox couple using 5-mercapto-1-methyltetrazole. Cells using this electrolyte were shown to have a power conversion efficiency of 6.4 per cent under standard illumination test conditions - comparable to similar iodide-based systems and much higher than other iodide-free cells. The electrolyte avoids the corrosion issues associated with iodide and has improved optical properties. 

'An efficiency of 6.4 per cent achieved under full sunlight sets a new benchmark for iodide-free DSCs,' say the researchers, who add that the novel redox couple 'offers a viable pathway to develop efficient DSCs with attractive properties for scale up and practical applications'. 

Neil Roberston, who researches DSCs at the University of Edinburgh in the UK says, 'This is certainly a very promising step forward. It is not the first time that alternatives to iodide have been put forward, but this one outperforms the previous best alternatives. The electrolyte is a known problem with the manufacturing and long-term use of these cells, so it is important to address these issues for the future of these devices and to open up their application more widely.' 

 

References

M Wang et al., Nature Chem., 2010, DOI: 10.1038/nchem.610

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[neverdem]

An organic redox electrolyte to rival triiodide/iodide in dye-sensitized solar cells

[driftdiver]

How many years have they been working on solar and still don’t have a workable model for large scale power distribution?

Does anyone really want to cover square miles of land with these cells to replace a power plant?

[Wpin]

The promise of solar is to reduce the need for government monopolies of energy creation. I am excited that they are moving forward towards individuals being independent of the monopolies and government for our energy needs.

[MrB]

Look at solar as your way of actually having electricity at your house when the elites try to cut you off.

[driftdiver]

What makes you think the elites will let you keep your home? They are currently working to take away your 401K and other savings.

[MrB]

They can shut off our power without resorting to force.
They’ll do all they can to keep pushing us into tyranny without “triggering” us to respond.

[ExTxMarine]

True - BUT!!!

Here is the problem (just like E-85 and Obamacare, and all these programs that are subsidized with tax payer dollars) I am still paying! I am now paying for my own electricity and a portion of everyone else’s electricity, instead of just what I use!

If this technology was all that great, then it would be cost effective WITHOUT my tax dollars subsidizing the industry! My truck can use E-85, but I just don’t think it is good enough to pay for TWICE! I get half the fire-power from E-85, but get to pay for it twice!

[Wpin]

I do not disagree with you on the subsidies per se. But, in the end it will be the innovation of entrepreneurs creating technology that works for individuals that will free us from the government and it’s monopolies...

Think phone company... :) Or, maybe you are not old enough to remember when there was just one...

[ExTxMarine]

Nope, I am not old enough to remember that, but I worked for GTE after the fall out and I understand exactly what you are saying!

I agree, that true innovation and individual creationism will lead us to whatever it is we ultimately need/want to rid us of these government/utility over-lords!