Thursday, May 1, 2014

Printable solar cells

To allay my notorious pessimism about the future, I went to a talk today. It was about printable solar cells, presented by Scott Watkins, the very same CSIRO scientist featured in the linked news item.

And they are truly amazing. Much cheaper to produce than normal silicon solar panels, flexible (he gave some to the audience to feel), and very simple in their internal structure. Essentially the material scientists just print two layers onto a plastic sheet: first a polymer mixture, then a silver lattice that takes off the power.

In small experimental formats they have achieved the same efficiency as standard silicon solar cells; in larger formats, efficiency is still considerably lower, but they have various polymers to play around with, and they have not even tried how the best mixtures they have already developed work when scaled up, so there is still a lot of potential for improvement. Because so many different polymers can be employed, it is also possible to tailor the printable solar cells to different light wavelengths.

Apparently even in the best case they will most likely not achieve the lifetime of thick and solid silicon solar panels, but again, they will be considerably cheaper. Once the research consortium has settled on the best materials for efficiency and durability, this will have enormous potential.

There is, however, one possible irony: The plastic that the solar cells are printed on, and the polymers themselves, are made from oil. Perversely, that means that the more oil we waste for cars and heating now, the more difficult it will be to produce this type of solar cell in, say, 2050; and the same for any other type of plastic, for all their various uses. Okay, the outlook is not entirely bleak, because some polymers can be made from biomass, but that will be more difficult and use land that could otherwise produce food.


In other news, and certainly completely unrelated to the question of our distressing overuse of petrochemicals, today somebody incredulously asked me if I really rode the bike to work every day, even now in the "cold" "winter" here in Canberra.

Well, yes. It is one hour of exercise every day (30 min each way), with the added benefits of saving money, saving the aforementioned resources, and not getting a fit while standing in the traffic jams on Mouat Street and Northbourne.

Also, it is not cold, nor has Canberra got a winter. I'd say it has four months of what would be late autumn in Germany followed immediately by spring. (Which might be a reason why no native trees have ever evolved to be deciduous.) And of course I also rode my bicycle to university when it was -10C back in Germany. There is no wrong weather, only wrong clothes, and it is not the weather's fault if Australians believe that they should be able to wear shorts and flip-flops at all times.

No offence meant. Just saying.

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