I make glass with some regularity in my material science class. We batch glass and add in manganese oxide (purple), chromium oxide (green), copper oxide (light blue), and cobalt oxide (dark blue) to produce colors.
From watching this video, I'm thinking I may need to buy some new crucibles and try other oxides to check out more colors. I'm not as worried about their color under UV light - though that is kind of gorgeous - but rather under various visible light sources.
Anybody know of a better, reliable, cheap source of neodymium oxide than thesesources? I'll be honest that 1/2 a pound - even 1/4 pound when we're using less than a gram per batch - would last me pretty much forever.
I was watching a YouTube video from a Scottish YouTuber recently and heard him refer to a light as being a LED bulb. He, however, pronounced LED as if it were the element lead. I, an American, pronounce those bulbs as their three separate letters El Ee Dee, like an acronym.
Neither, of course, is correct, nor is it at all relevant to this video.
This video, just over half an hour long and produced by Dr Derek of Veritasium, goes through the quantum mechanic explanation of how semiconductors conduct at room temperature which also explains how LEDs produce light and - eventually in the video - how LEDs can be tuned to produce different colors.
This video is also a great exploration of how doped semiconductors conduct electricity.
I'm really happy that I don't have to teach this concept in my chemistry - or material science - classes because this really pushes my understanding of quantum mechanics and electronics. I didn't thoroughly understand it when I first heard about it back in 1993 or 1994, and I don't entirely understand it now. I do, however, fully accept that there are people who do understand these concepts and that we owe those people a massive debt because the widespread use of LEDs has been a huge revolution in energy savings for our world.
That looks a whole lot like solgels to me, but I'll admit that my knowledge of solgel chemistry is about twenty five years out of date and based on a single summer of research at Miami University (no, not University of Miami).
The video summarizes researchers' findings that amino acids can form glasses with an index of refraction close to that of silica glass, adhesive properties, and a natural inclination to form convex lens shapes...and that self heal themselves as they rehydrate themselves.
The idea that we can create structural color - akin to that found on the wings of butterflies - using a diffraction grating and some tempered chocolate is pretty amazing.
Diffraction grating isn't too expensive, and chocolate is pretty cheap.
And they are incredibly rare and labor intensive to mine.
So why not just make them at home?
All it takes is seven or so months, a fume hood, some ethyl alcohol (purer is better), tetraethyl orthosilicate, ammonium hydroxide, a stirrer, water bath, hot plate, resin, a vacuum chamber, and apparently infinite patience.
In the fall of 1995, Professor Arthur B Ellis of UWisconsin came to Wabash College - where I was then a senior chemistry major - and gave a presentation about LEDs. At the time I knew of LEDs as the little red or green light bulbs that were pretty much used as power indicators on electronic devices. I didn't - before his talk - have much of an idea how they worked or how important they would come to be in our world now twenty-five years later.
Coincidentally, Dr Ellis had just written Teaching General Chemistry: a materials science companion, a book that my cooperating teacher bought for me after my student teaching semester later that academic year and that I accidentally re-purchased twenty years or so later. (I realize now that I've told this story on the blog before.)
But I digress...I have come to realize that Dr Ellis's lecture at Wabash really laid out the chemistry of LEDs marvelously well because I watched the above video - showing the LEDs and solar panels are of a kind - and the below video - in which Steve Mould explains the science of LEDs and how they turn electricity into light (and the reverse in solar panels) - and realized that I already knew that information...even down to the P- and N-type semiconductor information.
I've never had a chance to thank Dr Ellis for his lecture, so maybe - if I'm lucky - he'll come across one of these blog posts and realize that he's appreciated.
We can maybe back off with the question mark-exclamation point ending on the title, folks.
I'll take 'not 100% transparent' any day of the week if it means that we can turn our windows into solar panels. That would be outstanding.
I am a little curious, though, about just how 'not 100% transparent' they would be. The whole <640 nm thing would be around red/orange, and their explanation that longer wavelengths would travel right on through seems odd. Longer than red/orange doesn't leave a whole lot of colors because the rest of the colors are shorter wavelengths than red/orange.
I mean it's a gorgeous blue, but it's a blue that doesn't seem quite right.
Apparently - at least according to this article - there's no copper in the water, so that's not what it's blue.
Instead, the Rio Celeste produces particulates of aluimosilicate of exactly the right size to reflect light in the blue area of the spectrum. Neither tributary contains particles of the right size, but...
[t]here was only one puzzle left to solve, though. If Rio Buena Vista also had an abundance of aluminosilicate, how come its water looked completely transparent, while Rio Celeste appeared to be turquoise? It turned out to be a matter of particle size. Upon analyzing samples from both bodies of water, scientists realized that aluminosilicate particles in Rio Buena Vista measured 184 nanometers (nm), while those in Rio Celeste were much larger at 566 nm
“This increase in size is what causes the scattering of sunlight, such that it occurs principally in the blue region of the visible spectrum. So that’s why we have that spectacular light blue color of the Rio Celeste” said Dr. Max ChavarrÃa Vargas, who lead the scientific investigation into the turquoise waters of Rio Celeste. “It’s one of those quirks of nature where one of the rivers provides mineral material with one size and the other river provides the acidic environment so that those particles grow.”
That's initial image of the vantablack looks entirely like a special effect.
Vantablack is the lest light-reflective material (coating, really) ever. The video suggests its usefulness inside telescopes, which makes sense. I'm curious, however, where else it could be found useful.
Total internal reflection seems a simple enough concept, but to envision is causing the light signal to bounce down and down and down a flexible, glass rod effectively into infinity is a little harder to imagine. Here a British professor explains the concept of total internal reflection as it works along an optical fiber (or fibre for the Brits).
