Researchers achieve greater efficiency by manufacturing solar cells from crystal silicon

May 14, 2013, University of Stuttgart
Credit: 31_laserlabor2

Photovoltaic systems are indeed enjoying a boom worldwide, yet the situation for German manufacturers of solar cells and module is critical. The reasons for this are worldwide excess capacities and manufacturers from China who have flooded the world market with modules with approximately 15 % efficiency at dumping prices. German and other European manufacturers will only be able to keep up if they are able to offer cells and modules with higher degrees of efficiency at competitive prices. The Institute for Photovoltaics (ipv) at the University of Stuttgart has now set a new record in the hunt for the highest degrees of efficiency using the simplest possible production processes. In a project funded by the Federal Environmental Ministry, success was achieved in manufacturing cells from crystal silicon with almost 22 % efficiency.

The secret of success lies in a laser process developed at the institute with which it is possible to manufacture rear side contact cells without any masking steps whatsoever. This means that only almost half of the process steps are necessary that were required up to now in the industrial production of such cells.

Prof. Jürgen Werner, Manager at the Institute for Photovoltaics at the University of Stuttgart: "We now have 22 % cell efficiency. Now the 23 % mark must be attempted, however especially the implementation in industry. The cell process should be able to be implemented in production relatively quickly."

Standard have front side contacts made of silver. These metal fingers obscure parts of the cells and reduce their . In contrast, "rear side contact" have no contacts on the front side; all contacts are on the rear side. This solar cell type, however, requires a very fine structuring of the doping and contacting of the rear side. Usually to manufacture the fine structures elaborate and expensive masking steps are then necessary. Through the laser process, these steps are no longer necessary: it enables the manufacturing of the various doping procedures with a resolution below three hundredth of a millimetre.

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2.1 / 5 (14) May 14, 2013
Considering the number of advances in solar energy production, and the number of times cheap and effective means for harvesting solar energy have been developed, it seems likely that whenever the world is ready to wean itself from fossil fuel will. Throw in wind, ocean and other methods for tapping into renewable energy, and it becomes rather obvious that the only thing really keeping the world addicted to fossil fuels are its providers-profiteers.

It would be nice to be hopeful that as a species and civilization we are almost ready to end this addiction. But that is tantamount to hoping we have outgrown destructive levels of greed. Which clearly has not happened yet.
1 / 5 (4) May 15, 2013
We will never wean ourselves off of fossil fuels because
1: They meet base load demand.
2: We use oil derivatives such as asphalt tar, pharmaceuticals, plastics, rubber, paints, lubrication oils, etc so is a government regulator greedy if he/she wants to take away freedom from citizens by more regulations.

Is a person greedy if he/she wants to tax/confiscate other peoples money? There is no such thing as the absence of greed. At least in the private sector greedy people produce marketable goods and services. Greedy people in government just politically and uneconomically malinvest tax money into their pet projects. eg the DOE funding alternative energy tech for over 3 decades but only gaining less than 2% of the national energy market.
2.3 / 5 (12) May 15, 2013
When I referred to fossil fuels, there was an emphasis on "fuels," as I was discussing energy alternatives and not asphalt, pharmaceuticals or plastics.

Weaning off of fossil fuels does not necessarily imply a total abstinence from fossil fuel use. In an age when nuclear power is fed into our energy-grid, we still burn wood and coal. And we will be burning oil for a long time to come. "Weaning" refers to ending our addiction, to shifting to other sources so our reliance on fossil fuels harms us and our environment less.

If you are so enamored of greed, then you should be gratified that your politicians practice it so blatantly and enthusiastically. Greed infests the political system, which is so thoroughly corrupted by it that bribery is now open and legal.

I am not looking for an absence of greed. Just a mitigation of destructive levels of it, as I wrote in my post. Humanity's interest in its own survival will curb the greed, but sooner would be better than later.

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