Hi Blogfaces,
If I seem in high spirits, it's because today marks the conclusion of my 21st straight year of being in school. That is way WAY too much education. Time Magazine would probably think I've achieved a dangerous amount of “lurninz” at this point, and as such shouldn't be trusted. See, Time recently ran an article detailing all these mistakes educated people have made in the past, and thus insinuated that since the well educated have made errors, clearly idiots are better at making decisions. It was... AMAZING.
If that first paragraph is any indication, todays blog post is going to be fairly stream of consciousness, and for this, I'm sorry. I've had a long long week. Incidentally, if anybody would like to know anything about the production of cadmium telluride based photovoltaic devices, I got yo back. But summer is upon us (nearly). The majority of undergrads shall scamper back to their parents places of residence and a wonderful quiet will drift onto campus. It is my favorite time of year.
Well, I've spent all week working on a talk and paper about cadmium telluride, and as my brain is tapped out, guess what I”m gonna write about about...
CdTe: The Best Solar Cell Solution We Can't Have!
Here is the thing about CdTe, it's a nearly ideal material for solar cells, at least solar cells you want to mass produce. Sure, they got cells with better efficiency (CIGS) and they certainly got cells made out stuff that isn't cadmium (silicon solar cells), but nothing we got quite matches the ease of production than CdTe cells. I mean, you can electrodeposit this junk, you can close-space sublimate them, you can hot-wall sublimate them, you can screen print, you can chemical spray, cadmium telluride don't care WHAT you do. It's gonna form a wonderfully stoichiometric p-type zinc blend structure. You sandwich that in there with a little cadmium sulfide, throw down a couple of contacts, bada-bing-bada-boom you got yo self a 16% efficient solar cell! Sure, there is some garbage in there about “activating” the two layers together so as to avoid any crippling 5% lattice mismatch, but what's 5% between friends. What? A 5% mismatch drops your overall cell efficiency down to 2%… That's both interesting and terrible news! Ah well, we heat that garbage up (in the presence of chlorine, you know, to act as sort of a social mediator between the two materials) to like just under 600 C, and CdTe and CdS be like best friends again.
Ok, so if it's such a great solar cell material, easily processed with currently available technologies, why ain't I going out and investing in it right now? Well, you could. First Solar, your Toledo based Wal-Mart owned photovoltaic production company is a big fan of these. They've actually set up quite a few home instillations as well as large scale solar farms. So the problem? The problem is that this technology might actually take off. Here is a solar cell that could actually really go be affordable in the near future, as First Solar has claimed to get prices below a dollar a watt! So what would happen then? People would start buying them up. Demand would rise. That's when the little “Te” component of our solar cell becomes a huge pain in our little green energy butts. See, Tellurium is the 9th rarest material on the planet, more rare than platinum. If you go digging around, for every billion chunks of rock you look at, about 24 of them will be platinum, but only 2 or 3 will be tellurium. Precious stuff. Thing is, if we were to go out in space it'd be a lot easier to find. For some reason, the earth just don't have a lot of Te, but the rest of the galaxy is abundant like rubidium with the stuff. And you know how much rubidium we got laying around. Mad amounts.
So where does that leave us? Well, we've got a really great material that makes really decent solar cells and if we ever decide to start using it on a large scale, we'll run out of the materials to make it quickly quick like. Shucks.
So what is our energy solution? What do we use? I call for large scale adoption of hamster powered flywheels running huge turbines. It'll be the most ambitious and adorable venture this nation has ever undertaken. My god, can you imagine the squeaky wheels? I'll be the first to admit this plan has some holes in it but you can't tell me you wouldn't want to see a giant power station filled with hamsters running on wheels.
~bd
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Can't we just use all of the undesirable minorities to... space mine... tellurium? We can get rid of immigrants, the lower-class, the homeless, homosexuals, bisexuals, cocky breeders, liberals, conservatives, the rich, atheists, Christians, Jews, Muslims, slack-jaws, the dreaded over-educated, southerners, yanks, whites, blacks, yell'ers, reds, browns, foreigners, alcoholics, teetotalers, and pretty much everyone else by making them... space harvest... tellurium. Then *poof* cheap solar energy!
ReplyDeleteCadmium is quite poisonous and especially problematic if it gets into the water supply. These type of cells are banned in Japan due to some Godzilla level cadmium related disaster. In fact all studies on human toxicity are related to Japanese people who ate rice grown in cadmium contaminated soil.
ReplyDeleteGuy: See, i was thinking that this would be a perfect use of our missile defense system. Just shoot down passing asteroids and scavenge wherever it lands. Granted, your idea is good too. I suppose we could strap the "undesirables" ONTO the missile defense rockets and just send them up there.
ReplyDeleteKing: See, the bond between cadmium and tellurium is like 5.75 eV or something insane. No photons are gonna break that. So the theoretical only time you're gonna be in a position to liberate cadmium is a fire, and if that were to happen, the glass substrate of these cells would melt first (at like 600 C) and lock all the thin film inside it's molten self. So yea, somewhere around the rubble of a particularly hot fire you might have to find a big chunk of glass incased CdTe chilling out, but no appreciable amount of cadmium is going to escape. I think the Japanese should worry less about cadmium based photovoltaics and more about it's cultures obsession with vending machines filled with girls underwear and tentacle porn.
Have you ever met the General Public? Great now you get Cd and Te poisoning. Why not just make CdTe-SwineFlu cells? Forget this shit I'm going back to eating coal.
ReplyDeleteOh come now, tellurium just gives your breath a slightly garlicky smell. If anything, it's a wonderful addition to pasta salad.
ReplyDeleteAs someone who has lived in Japan, I can say with a good deal of confidence that they care a LOT more about their used schoolgirl panties and tentacle rape porn vending machines than... well, pretty much anything else.
ReplyDelete