The blue LED was supposed to be impossible—until a young engineer proposed a moonshot idea. Head to https://brilliant.org/veritasium to start your free 30-da...

The blue LED was supposed to be impossible—until a young engineer proposed a moonshot idea.

  • JATth@lemmy.worldEnglish
    641·
    9 months ago

    This was an yet another glorious episode from veritasium.

    I hope we get well past UVC LEDs. (i.e., shorter wavelengths) UV LEDs are already available. Unfortunately, this progress will stop before X-ray light. With +1 KeV energy, you pretty much must blast off the electrons from the atoms to emit X-rays, which an x-ray tube already does. Or by peeling off a piece of scotch tape.

      • JATth@lemmy.worldEnglish
        30·
        9 months ago

        Maybe not in a flashlight, but the scientific industry would be very pleased with them. Sterilize water and all surfaces in a second? Flash with 200nm light.

        • Hamartiogonic@sopuli.xyzEnglish
          1·
          9 months ago

          What’s wrong with the current UV tubes? Sure, the smaller ones take about 5-10 W to get the job done, so maybe an LED version would be more efficient. If you’re using UV to keep a massive pool clean, then you’re obviously going to be need more of those bulbs, and they can add up to hundreds of watts quite easily. Is that really a big problem though? Having a pool isn’t cheap, so electricity spent on UV probably isn’t going to be your main concern. Making it cheaper is always welcome, but are UV tubes really that big of a problem?

          • areyouevenreal@lemm.eeEnglish
            2·
            9 months ago

            I mean they aren’t instant and have to be within a fairly short distance of the thing you want to sterilize in order to work because they are absorbed by the air. Something like a pool would be practically impossible as water also absorbs UV and a pool is too big to penetrate all the way through just from the sides or bottom. It only works for drinking water because you pass said water through a tube that must be fairly narrow.

            Oh yeah and an X-ray could sterilize all the way through an object, not just the surface. Very useful for making things like microwave meals.

    • TonyTonyChopper@mander.xyzEnglish
      18·
      9 months ago

      More efficient compact X-ray generators would be pretty huge for science work. We run the diffractometer in my lab at 2 kW and it still takes hours to get a good quality scan

      • Mo5560@feddit.deEnglish
        4·
        9 months ago

        1. Light = energy, shorter wavelengths= higher energy. Blue light has a shorter wavelength than red light. UV has even more energy. X-Rays have a lot more energy. For reference in the visible spectrum were talking about maybe 1-4 eV (this may be wrong, I’m too drunk to look it up rn).

        2. If we want to produce light, the aim is to find an energy gap that has the exact energy gap that corresponds to the wavelength we’re interested in. Typically this corresponds to an electronic transition, i.e. an electron “jumps” into a higher orbital, on its way down it will emit the energy difference as light.

        2.1 X-Rays rn are produced by accelerating electrons onto a metal plate with high voltage. The impact of the electron “rips” out an electron in the close vicinity of the nucleus. Another electron will take the place of that electron, the energy gap associated with that process is large, which is why it produces X-Rays.

        1. If we want to produce LEDs that emit in the far UV range we have to find large energy gaps in materials which is difficult. We still have to have a way to get the electron across the energy gap using electricity.

        2. X-Ray LEDs are probably not realistic, as the energy of x-rays is so large that we have to rip out electrons from the close vicinity of the nucleus… which is already what we’re doing with X-ray tubes.