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How to make quantum dots at home

The Thought Emporium - 2015-11-30

Hydrothermal carbonization is an amazing technique that allows for the creation of a diverse range of nanoparticles. This video introduces the idea of hydrothermal carbonization and what it's capable of. 
Quantum dots are particles that are right on the edge between single molecules, and large particles. As such they have all sorts of weird properties. One property is that they are highly flourescent! Normally, they're made out of toxic semiconductors like cadmium sulfide, but in this video I show how they can be made out of carbon instead! Best of all, almost any carbon source can be used as the starting material. I've used everything from sugar, to gelatin to orange juice with great success. 

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Xu Yang - 2019-03-31

Quick question: how was HCl involved in the hydrothermal synthesis? I only saw you mixed the gel into water to reach 30 percent. But where is the acid?

Kalanchoe1 - 2015-11-30

i'm just gonna say this is pretty cool.

vins0r - 2018-10-01

Profile pic fits

Gary Yin - 2016-09-07

when are u making the dots of other colour like red?

The Thought Emporium - 2016-10-12

Once I get my new lab set up (january-ish)

SaintTrinianz - 2018-07-14

Love this channel! 💕

Filip Opálený - 2019-04-27

Could this be used as a dye in fluorescent/confocal microscopy?

Blu Deat - 2015-12-01

must it be liquid of it can be solid? how about use polyvinilchloride with some hydrogen peroxide which will react with hydrogen

Shannon Amend - 2016-11-25

I made it. I used inplix scripts for that. It was pretty easy to make it

PAYAL JAIN - 2017-03-06

You use teflon tube reactor and steel pipe fitting.can steel fittings works same as teflon reactor.

zylascope - 2017-07-13

Thanks. A well made and interesting video. Awesome stuff.

Abhyuday Paliwal - 2017-10-02

Hey! Awesome video! Thank you so much for sharing it in public. Could you please answer one question though. I have read in papers that one has to do the dialysis process for purification of dots from the residue. Is it really required? Did you do for the C-dot synthesis of this video ? Thank you again for the awesome video :)

The Thought Emporium - 2017-10-03

I didn't bother only because I wasn't using these for something professional and was just making them as a curiosity. But yes, otherwise dialysis is necessary if you want to use these for anything.

giggythore - 2017-04-01

What was the HCl used for?

inferno - 2017-11-17

giggythore replacing a hydrogen atom with chlorine or vice versa (I can't remember which way around it was).

Jonathan Peele - 2017-07-28

Thanks for the video but it is really quiet. If it weren't for captions I wouldn't understand half of what you said.

Salah Sedarous - 2017-06-12

excellent
in fluorescence, it is called inner filter effect or self-quenching
thanks

Lou - 2018-07-22

Acid, Water and something with Carbon form something that glows in the dark?! O_O

FERRA FILMS - 2016-12-30

Hi! Just wondering about your safety precautions with the teflon hydrothermal synthesis reactor. Thanks.

The Thought Emporium - 2016-12-30

In short? probably not nearly enough. I would just keep a very wary ear and nose out for any sign of leakage. you'll smell burning from the reaction leaking out and burning in the oven. Soon as that happened I'd rush over, remove it from heat and cool it under water to drop the pressure. ideally you do it in a nice blast chamber. Also never go above about 210c. Anything over that and you seriously risk explosion. I normally kept it at 180 where the pressure doesn't get nearly as high.

Noah .Condotta - 2015-12-01

so cool

Zubr Bnoij - 2016-08-21

What was that acid for?

PAYAL JAIN - 2017-03-08

You use teflon tube reactor and steel pipe fitting.can steel fittings works same as teflon reactor.

The Thought Emporium - 2017-03-08

for this? Ya sure. That was how I did it the very first time I did this

PAYAL JAIN - 2017-03-13

Please guide did steel pipe effect the reaction on high temperature ??How to check pressure of steel pipe during reaction.Is teflon tube is required for process.

Bobbito Chicon - 2018-10-06

Can you ingest this like C60😁

Herp Derpingson - 2018-09-26

Alchemy increased to 100

weksauce - 2019-09-08

Alchemy intensifies

Ubya - 2018-11-25

but how are they produced? what is the reaction? i can't find any info. i did the experiment by mystelf and it worked, but i'd like to know the mechanism behind

peter lang - 2017-09-16

great video!

David Tsoraev - 2019-01-14

Is there any way to extract the dot's from the solution so i'll have solid particles without liquid?

mohammed SEKKAL - 2019-03-25

you can try to do a centrifugation , but not sure , i tried it last week for my bachelor's project but it was to small not good * i used glucose and peg-200 * i guess it might work with diffrent protocole than the one i used

Roy Garithos - 2019-08-31

it is, but i think to get them completely dry you need to purify the liquid so that its just quantum dots and water, and then dehydrate them in a freeze drier or other method of gently removing the liquid without moving the particles too much, as they are very small and the power is quite light.

Aftab Ahmed - 2016-12-11

i am making a synopsis on carbon quantum dots, can you suggest me a suitable title of the reserch

fischele - 2018-05-05

I tried this with the pipe autoclaye. For protection purposes, I put it into a pot of sand. Now I can't open it anymore, even itf I use a vice and wrench.
Any advice on how to open this?

The Thought Emporium - 2018-05-11

Lock the wrench on, hit it with a hammer. You just need to get it started and it'll go.

Davide Garibaldi - 2018-07-16

Did you put it in the oven you cook food ?

Steve Jose - 2019-07-10

Can carbon quantum dots be used as a dye for nucleic acids in fleurometer or nanodrop spectrometer for the estimation of its concendration ?

Jonathan Fosdick - 2015-12-13

Hydrothermal carbonization of orange juice (citric acid) produces graphene quantum dots. I can see you have synthesized various nanoparticles and I'm guessing you made copper and zinc nanoparticles too, as I can see what appears to be copper oxide in one of the vials. I am interested in knowing what the vial to the far right contains as it appears opaque white.

Jonathan Fosdick - 2015-12-13

Also, simple pyrolysis of citric acid (200-230°C/~1h) creates graphene quantum dots. Hydrothermal carbonization of simple sugars like fructose and sucrose forms graphene oxide, so if the reaction is partially completed graphene oxide quantum dots are formed in the autoclave. This is true when using this route with orange juice as well. Keep up the great work!

Cure Aging - 2017-01-17

Cool. I gotta try this with my flow cytometer. If the carbon dots really do fluoresce yellow and absorb green (maybe blue? Have you tried?) then this would make a great fluorochrome that exites/emits in the range of Phycoerythrin (PE) which is my favorite fluorochrome. I'll make it, neutralize the HCL with some NaOH and see if some cultured cells can take it up and glow.

Filip Opálený - 2019-04-28

How did it go? :)

Martin Cooper - 2019-08-03

Are quantum dots thermally stable? They could be added to plastics to be an identification marker for recycling.

Phonotical - 2018-07-28

Try it with neodymium oxide

NautiluS - 2019-01-05

So what can u do with it after?

MrSec84 - 2019-09-08

Quantum Dots are used in some modern TVs from SAMSUNG, TCL, Hisense and a few other TV makers to provide wider color volume for LCD TVs.

You could use Quantum Dots in your own projects to make display technology or just to mess around with for fun.

Moxie Gaming - 2018-05-19

What is the shelf life of these? I realize this is a numb question but could I put this in a watercoolant loop for a computer that or the dendritic copper mixed with ascorbic acid to keep the copper from degrading. Thanks

The Thought Emporium - 2018-05-20

If you purify them so there's no sugar left, just the quantum dots, then they'll last indefinitely. That said, I don't think they'd really help with cooling anything. The copper would probably clog like a blood clot if there's any small tubes which there usually is. Water is fine on it's own. Just used deionized water and it won't corrode nearly as much. Or add a small amount of ascorbic if you're so concerned but I have no idea how that would play with your system

prohri uhri - 2017-07-16

is it safe?? its look like a pipe bomb

The Thought Emporium - 2017-09-04

There is a risk of explosion, so you need to be careful, but it's just as dangerous as most other chemistry.

science put simply - 2019-09-26

@The Thought Emporium is it possible to add a way to relieve pressure

Jonathan Fosdick - 2015-12-13

One can make carbon dots (5-8nm dia.) from microwaving honey or molasses: p

Chickenug - 2016-03-12

is that true?

Liam whatever - 2018-07-26

can you do a video on the specific quantities to make each color of quantum dot. Particularly the light blue ones on the picture for this video. I need it to make a replica of a soft drink from a video game called fallout four. I always wanted to make a replica of it and I found a glass coca cola bottle that is suitable but i want it to actually glow like in the game. if you could thanks, because i think it would look pretty cool in a display case or something.

Akrer Games - 2018-07-19

Does graphite from pencils works too as a carbon source?

Roy Garithos - 2019-08-31

i think technically if you use the right chemicals, graphite by itself can be tough to react on its own and other elements are useful for catalytic effect

Dodo Ipavec - 2018-07-25

I tried to make quantum dots with oil, and succeed. I used sunflower oil (100ml) and 1ml of concentrated (97%) H2SO4, mix them together, heat to 100°c and at the moment it reached 100°c i put reaction flask  in water bath to cool it down. I got dark red (almost black) solution and by putting it under uv it glowed green.

Theminecraftian772 - 2018-07-01

What if I were to soak string or thread in a solution of these? Would it pick up the glowing property?

Roy Garithos - 2019-08-31

no reason to think it wouldn't, they would coat and stick the fibers and glow under UV, making the fibers appear to glow

Christian Gomez - 2015-12-25

How do you know that the fluorescence is not due to an impurity in the gelatin?

The Thought Emporium - 2015-12-26

+Christian Gomez The color is very distinct and is present at minute concentrations. Nothing in gelatin behaves like that. Also I've used spectrophotometry to look at the spectrum of each and they're quite different.

Christian Gomez - 2015-12-26

+The Thought Emporium It would have been a nice thing to include in the video.

The Thought Emporium - 2015-12-26

I'll be doing an update in the near future going through some variations on this where that will be demonstrated. I made this at 3 in the morning during exam season so it's not as detailed as i'd have liked. The next will be more in depth. 

Dad Dancing - 2018-05-22

I note that most experiments involving quantum dots only talk about luminescence using light.

I wondered about the passage of electricity through the more concentrated solution of QD's.

Can we get that more concentrated solution to luminescence brightly by passing electricity through it?

Is this how QDs are lit in Quantum Dot television applications? Using electricity?

Roy Garithos - 2019-08-31

every electrical reaction can be reversed to produce the opposite, and quantum dots glow when excited by UV radiation causing them to glow (they are after all semiconductors) so it stands to reason that electricity should be able to control and enhance their glow like LEDs

as a sidenote/example, LED's are technically photovoltaic (like solar cells) because they use the same property (in a different way for different effect) in reverse of solar panels, where solar panels are built to be better at converting light to electricity, LEDs are designed to convert electricity to emitted light

Ismail AIT OULAID - 2017-04-13

What is Carbon Dots ?

Cameron Webster - 2017-03-09

Might want to buy the pipe fittings from two different stores

TheRealBob Mayo - 2018-08-07

Cameron Webster help me i dont get it

Akrer Games - 2018-08-07

Asdf Qwerty Homemade pipe bombs are made with 2 fittings, a piece of pipe and some gunpowder, most people know that

TheRealBob Mayo - 2018-08-09

Akrer Games oh, duh.

Zael Slyte - 2019-01-19

@Akrer Games I didn't know that. I'll have to try that out sometime

Roy Garithos - 2019-08-31

@Zael Slyte try it with 1 part sulfur and 3 parts zinc instead of gunpowder, get a green explosion

Lindy Oneill - 2016-08-06

Are they safe.

Kyler - 2018-07-24

Lindy Oneill He said they’re extremely toxic in like the first 2 minutes. (Cadmium Sulfide)

MethyleneVapour - 2018-11-30

@Kyler these are not made of СdS but of carbon

Roy Garithos - 2019-08-31

depends on the dots you're making, lots of commercial sources of quantum dots are cadmium sulfide which is toxic, but the quantum dots he made here are carbon, so if any of the ingredients aren't toxic to begin with there's not much reason to believe the dots themselves would be

LKHB hydroponic - 2018-07-14

So cool. Is it dangerous to explode?

Think Ramen - 2017-03-14

very coolstuff, at a company Ina school I go to in Utah, granite technical institute they are doing exactly what you did with the laser, but implementing it into TV's so that white light can change to various colors, they are making really great progress, don't know the details of the project just got some info from a teacher😀 it's sounds really promising though

The Thought Emporium - 2017-03-15

Ya guantum dot tvs are already starting to become popular, at least amongst scientists. Pretty great stuff

ZodaChem - 2018-04-27

Did you check if they are stable in water and not aggregate ? Have you tried to separate the particles by size ? I work with carbon nanoparticles and I can tell you that with that method you have particles of any size, so saying carbon dots it is not exact because dot are the ones with diameter less than 10 nm.

Rick E - 2015-12-01

is hydrothermal synthesis used to create nano particles for nano medicine? would be interesting to know if it could be made using this technique.

The Thought Emporium - 2015-12-13

+rikleybanw it's one step in a long process, but yes. I'll be unveiling just such a system in 2 months. stay tuned

Jonathan Fosdick - 2015-12-13

Usually, the nanoparticles are separated from the unreacted precursors by ultracentrifugication or by electrophloresis (chromatographic separation) before using.

Rick E - 2015-12-14

THANK YOU subbed. 

morgengabe1 - 2017-01-17

Be careful. Are you sure the glowing isn't radioactive?

The Thought Emporium - 2017-01-17

There's nothing in there that could have made them radioactive. That would require way more energy than an oven can provide. And the glow only starts when you shine a uv light on them. Otherwise they just look like a weird yellow solution that doesn't glow. It's called fluorescence

morgengabe1 - 2017-01-17

Oh, I missed the UV part lol. Fairs, merry synthesis my friend!

Shadkaam Ahmed - 2017-07-20

can we use corn starch instead of gelatine ? or glucose or glycerine?

The Thought Emporium - 2017-08-04

sure! I've done this with lots of carbon sources. Even orange juice works, though the color is slightly different

Shadkaam Ahmed - 2017-09-04

+The Thought Emporium is it safe though, the reactor won't blow up right?

Roy Garithos - 2019-08-31

@The Thought Emporium i wanted to ask about that actually, what color were your dots and what was your method for the orange juice? i want to cross reference it with my own results.