Energy. It is the string that binds us all together. Whoever we may be, wherever we may live, and however old we are, we all use and depend upon it every day. And as a general rule, we all want more. So when it starts to hurt our environment, we rationalize it. Oh, its only a hurting it a little bit, or its only me doing it, so that will be alright. Or even more disturbing, we look for any fake, unscientific reason that we can find to convince ourselves that it isn’t real. Because if its all a lie of the liberal media, than I don’t have to pay attention to my energy usage, and I don’t have to pay for development of alternative energies. Anyways, there are many solutions proposed, some far out, and some not. The paper “Loss analysis of emitter-wrap-through silicon solar cells by means of experiment and three-dimensional device modeling” explores some of the solar energy aspect of the solution and researches on whether a cheaper model of the classic photovoltaic cell could become efficient enough on its energy conversion to replace the more common, more expensive version.

    The world’s climate is changing. That is fact. The icecaps are melting, the polar bears are dying, and soon all of the people will follow. OK, maybe that’s an exaggeration, but you get the point. Fossil fuels are bad for us. They’re basically like cheating at life. Let me explain. They are easy, cheap, and highly condensed energies, but they ruin the environment, and there isn’t really many more of them (the cheap, easy to access ones at least). So you are basically cheating your future for the present. This has stop if we are to continue living on this wonderful earth. Unfortunately there are things standing in the way of our ‘green’ takeover. While most of these are corporations or special interests, we will be talking only about the technological gaps that need to first be made. One of the biggest of which, is to lower the cost of ‘green’ energy solutions without lowering the quality of them.

In short, we need to make them more economically sound. They need to be able to compete on the free market with other fossil fuel products, and with coal produced electricity. This needs to happen to get the people behind a ‘green’ economy. And one of the major stumbling blocks in this sense is that of coal power. For how much power it produces, coal power is extremely cheap and easy to produce. And this is a problem because to become green, solar power must be able to compete with that, which it just can’t right now. Most of this is due to the high cost of materials to produce solar panels. A new way to make solar panels, dubbed EWT panels dramatically reduces the cost of making the solar panels, but unfortunately also decreases the energy conversion efficiency by a significant amount.

    The classic photovoltaic cells average around 25% efficiency, while the EWT (emitter-wrap-through) cells are averaging around 18%. Researchers are saying that this is due to the historically low ‘FF’ values of the EWT cells. Most agree that the low FF levels can blame this is on the relatively high resistance in the rear end of the cell as compared to the classic cell’s.  This article attacks that assumption to see if it holds water, and if not, to see what may be causing the EWT cells to be performing under expected efficiency values as predicted by the common device theory.

    By means of many 3D device simulation the researchers in the article showed “that the VIRE effect causes the front emitter of an EWT solar cell to operate systematically at higher bias conditions than the external voltage probed at the rear emitter. As the difference of the bias of front and rear emitter diminishes with increasing external voltage, the VIRE effect reduces the
FF of EWT cells.” This results in a less efficient photovoltaic cell, but according to the researchers, they have found a way to at least partially correct this. They say that their “simulations predict that EWT design with a nonpassivated rear emitter and a homogeneous emitter diffusion leads to an efficiency improvement of about 1% absolute as compared to the common FJ design.” So basically, decreasing the resistivity of the base metal by a significant amount can result in the increase of efficiency by 1%, which may seem small, but would save many people quite a bit of money.

    In conclusion, EWT cells show much potential due to their relatively low cost of production as long as the producers find other creative ways to raise their efficiency, because, as significant as 1% is, it is just simply not enough to compete with coal.

Works Cited

Ulzhöfer, Christian, Pietro P. Altermatt, Nils-Peter Harder, and Rolf Brendel. "Loss Analysis of Emitter-wrap-through Silicon Solar Cells by Means of Experiment and Three-dimensional Device Modeling." Journal of Applied Physics 107.10 (2010): 1-12. Web. 23 Sept. 2011. <http://ehis.ebscohost.com/ehost/detail?vid=4&hid=101&sid=f907b4bd-d6e2-4366-b166-7369d22f13a6%40sessionmgr110&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=aph&AN=51060806>.