There's a layer of iridium due to the impact that wiped out the dinosaurs. http://en.wikipedia.org/wiki/Alvarez_hypothesis#Evidence On Tue, Dec 4, 2012 at 8:01 PM, Henry Baker <hbaker1@pipeline.com> wrote:
The good news is that "quantum dots" don't depend upon normal valence electron energy levels in order to achieve their properties.
Their properties are primarily a result of their size & configuration, which is in the 5-20 nm range -- almost achievable in the next 1-2 generations of lithography.
So many of the needs for exotic materials with very specific bandgaps will be replaced by these engineered quantum dots. --- It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
At 04:42 PM 12/4/2012, Warren Smith wrote:
Iridium is 40x rarer than gold and total world production is only about 10 tons annually.
Indium is also pretty rare, but not as rare: 1000 ton annual production. So I think if iridium is a substantial component of solid plastic lighting source then that will not be a useful technology for Average Joe Consumer. I would think you'd want ingredients common enough for million-ton production. If they can remove the need for Iridium and other rare elements, the general concept sounds excellent as a future lighting source.
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