How Does Fluorescence Work?

How Does Fluorescence Work?


We don’t need to get into the bright details
to uncover this fact: fluorescent colors look amazing. Whether you’re looking at a dayglo poster
under blacklight or reviewing a reference, you can’t help but wonder what makes these
colors stand out from the rest. Today we’re digging into what makes them
pop, and we’re going highlight some of the brilliant applications of fluorescence coming
out of nanotechnology. (Splash) Now About that highlighter – High, light,
makes sense. Under the sun it looks bright, under black
light, it looks out of this world. Inside this seemingly magical yellow ink you’ll
find a vibrant compound called pyranine. To understand how this stuff gets its brilliant
glow, let’s see why colors pop in the first place. This right here is the electromagnetic spectrum,
a chart that shows us the different wavelengths of photonic radiation out there. Now, right in between ultraviolet and infrared
radiation rests the visible light spectrum, a literal rainbow of frequencies that our
human eyes can see. We don’t need to get into the bright details
to uncover this fact: fluorescent colors look amazing. Whether you’re looking at a dayglo
poster under blacklight or reviewing a reference, you can’t help but wonder what makes these
colors stand out from the rest. Today we’re digging into what makes them pop, and we’re
going highlight some of the brilliant applications of fluorescence coming out of nanotechnology. (Splash) Now About that highlighter – High, light,
makes sense. Under the sun it looks bright, under black light, it looks out of this world.
Inside this seemingly magical yellow ink you’ll find a vibrant compound called pyranine. To
understand how this stuff gets its brilliant glow, let’s see why colors pop in the first
place. This right here is the electromagnetic spectrum, a chart that shows us the different
wavelengths of photonic radiation out there. Now, right in between ultraviolet and infrared
radiation rests the visible light spectrum, a literal rainbow of frequencies that our
human eyes can see. When light hits an object, the different wavelengths essentially do one
of three things, depending on the structure of the chemicals making up that object: 1. They
get sucked up by the chemicals – that’s absorption. 2. They bounce off the chemicals
– that’s reflection. 3. Or they pass on through – that’s transmission. The reflected
colors are what have a chance to make it to your eye, so they make up the object’s color.
Fluorescence is a trippy happening related to absorption, that can give you access to
colors normally outside the visible spectrum. When you see something fluoresce, you’re
kinda seeing a secret world beyond normal vision. Chemicals like a yellow highlighter’s
pyranine have structures that absorb light from the ultraviolet range of the spectrum
— wavelengths that our eyes can see. When these molecules absorb this funky light, they
become excited into a higher state of energy and release most of this extra energy in the
form of visible light, while the rest is released as heat. This means the objects are giving
back more energy than they received from the visible light source, which explains their
gleaming vibrancy under UV. And you may have noticed already, that “black” lights only
illuminate objects if they’re fluorescent. Another surprisingly fluorescent liquid is
tonic water. This otherwise clear liquid contains a compound called quinine that’s derived
from cinchona tree bark. This stuff fluoresces super bright under a black light, illuminating
gin lover’s’ glasses, everywhere. But there’s far more to fluorescence than Unicorn
posters, as with all other interesting materials properties, chemists have set their sights
on fluorescence and come up with some brilliant applications. For example, fluorescence is
expanding our understanding of microbiology: The newly discovered fluorescence of nanodiamonds
have given researchers the ability to study how they interact and move through cells at
much higher resolution. This may help lead to better, safer nanomaterials in the future.
Not to mention the use of fluorescent quantum dots – a bright light nanomaterial found in
some newer TV screens. These nanoscopic crystals are allowing us take a closer look at the
structure of cells and can even identify and mark cancer cells while avoiding healthy cells.
Speaking of biology, forensic crime scene investigators use fluorescence too. Not only
do certain bodily fluids like saliva fluoresce, blood absorbs UV, so splattered spots appear
black, not red, under blacklight. Also, for catastrophic car accidents, antifreeze is
used as a fluorescent marker that helps investigators understand how an accident occurred. We want
to give a big thanks to our friends at the NSF’s Center for sustainable Nanotechnology
for helping us bring this video to life. For more nanoscience goodness, head over to their
blog – there’s a link down the description, and while you’re at it check out this extra
lifehack video on to how to make a white flower turn fluorescent! Make sure to hit thumbs
and subscribe on the way out, but before that, post that chemistry question of yours in the
comments and we’ll see you again very soon.

17 thoughts on “How Does Fluorescence Work?

  1. Don't forget luminol, which aggressively binds to hemoglobin and fluoresces under UV. This allows investigators to find trace amounts of blood and can even reveal blood spots that were washed away.

  2. I'm pretty sure fluorescent dyes don't release more energy than they absorb…they release higher wavelength light

  3. I'm curious. Can I make a home brewed beer glow? As boil quinine for 15 min in a Pilsner. Could that work? Beer naturally is Opaque though

  4. can you speak slowweeeeer in your next videos pleaaaase
    my brain is overwhelmed with information it cannot followwwww

  5. Will the highlighter eventually dim under the UV light due to it losing the excited state of energy over time?

Leave a Reply

Your email address will not be published. Required fields are marked *