NurdRage - 2012-05-07
In this video we make cadmium selenide quantum dots. WARNING: This experiment uses toxic and carcinogenic reagents and directly handles extremely hot liquids. Gloves, protective clothing and a fume hood should be used. This should be performed by, or under the direct supervision of, an experienced chemist. Make trioctylphosphine selenide solution: Combine 30mg of pure selenium powder, 5mL of 1-octadecene and 0.4mL of trioctylphosphine. Gently heat it until all the selenium dissolves into a clear liquid. Once it's ready, take off heating, seal it and let it cool. Make quantum dots: Combine 13mg of cadmium oxide, 0.6mL of oleic acid and 10mL of 1-octadecene. Heat the mixture until the cadmium oxide completely dissolves to form cadmium oleate. After the cadmium oxide dissolves keep heating until the mixture hits 225 degrees celsius. Inject 1mL of the trioctylphosphine selenide solution from before and shake. Quickly withdraw small ~0.5mL portions of liquid and quench by placing it into vials at room temperature. A more narrow particle size distribution can be obtained if the vials are cooled on dry ice. The first several portions should be removed as fast as possible. The remaining portions may be withdrawn when there is a visible color change. What's happening is the cadmium oleate is reacting with the trioctylphosphine selenide to form cadmium selenide. These particles start small but grow in size the longer the solution reacts. Now this growth only continues if the temperature is maintained so withdrawing it at regular intervals and placing it in a room temperature vial stops the reaction and locks the particles into their current size. The oleic acid surrounds, or "caps", the particles and keeps them from aggregating. The quantum dots will fluoresce under ultraviolet light. It is recommended to use a fluorescence spectrometer to observe the differences in wavelength emitted. But a good digital camera can also distinguish the differences and exaggerate them for human observation. References: Boatman, E. M.; Lisensky, G. C.; Nordell, K. J. J. Chem. Educ. 2005, 82, 1697--1699.
you should do this experiment again, but do the whole final reaction under the UV light so that the camera can show the color changing as the particles get bigger.
Cool idea
the mark of the beast is coming! jesus loves you! dont do it!
This is, by far, the most impressive chemical experiment nurdrage ever made.
That is incredible. Thank you for making another amazing video, NurdRage
After watching this, I am definitely going to study the characteristics CdSe quantum dots for my Physical chemistry product. Woo hoo for fluorescence, X-ray diffraction, and TEM!
+SteveYoTalbot X-ray analysis? You'll be going postal before you get any valid results, trust me.
+R Johnson There is definitely a few way you can ultracentrifuge the nano particles out of solution and prepare them so that they can be viewed in a powder in the XRD. It has been done before. The only reason I'd like to do this is to observe the phases and structures as the reaction proceeds.
Wow, this is awesome! Thanks for posting! :) Could this be an example of the photoelectric effect?
I absolutely love these kinds of videos. Simple, easy to follow reactions that don't take a long time and result in a useful product. I'm going to use this to make a glass lamp. I'll react a fairly large amount and fill a glass lamp with it, then put a UV bulb in it . Thank you NurdRage.
this is awesome. I love how many different things can be done with science.
Hey, this was a great video. The safety warnings, basic theory, actual experimentation, analogy and citation are all done excellently.
No it's perfectly fine and even encouraged, you are what we call: "the future"
This is truly fascinating, it's one of the thousands of reasons I chose to do a chemistry degree.
Awesome videos! Always enjoyed chemistry and your channel fuels my enjoyment! Thanks!
@NurdRage Im curious, What would be the most complex experiment you have done? And have you made a video on it ?
Cheers for the videos.
Wow, this is so amazing! I am very fascinated by this.
interesting, i learn something new everyday :) I'll see what i can do about the filters, i don't have one on hand but i'll keep it in mind next time i'm out ;)
Always love seeing new videos-as always, thanks
alright, sorry, i've had a bad week. :) thanks for understanding. My point still stands though, while this may not be accessible to most people, i'll still teach it because i aim to educate, enable, and inspire. It's the few people that can do this and improve upon it that drive us forward. And it's the rest of us that understand and appreciate this work that we get out of their way and support them to make it possible. Q-dot based imaging agents are not far off, i hope you use them ^_^
Out of all the chemistry channels I watch, your videos are consistenly one of the highest quality, and everything is explained clearly, and in an interesting way. I hope you keep making these videos, I look forward to each one!
This is amazing :D great work!
Love your videos, I've shown them to my org chem prof and she can't get enough of your videos.
Hi, may I know what solvent do you use (as a reference spectrum) for measuring the absorbance spectra of CdSe quantum dots solution
Just took the AP chemistry test. Your videos actually helped me answer one of the questions THANK YOU!
Im a chemist working on photocatalysts for catalyzing various reactions under light and im gonna use your video instead of literature to make quantum dots :D, I wish I could cite this in my publication
This was fucking awesome. I love chemistry and all the geniuses who further it.
This was awesome! Thanks for the vid!
very cool!! I'm so impressed, can you explain why they have diff properties at the quantum level? that would be very much appreciated!
Awesome experiment. Have you tried doing the reaction under UV light to see the color change in real-time?
Every time someone says you are wrong, you end up being right. YOU ARE AMAZING!!!!
I remember when you were only getting a couple thousand views a video, my how your fanbase has grown nurdrage!
I am currently working on production of quantum dots in my lab, using this amazing video as a guideline for preparation. My question to you is, will this method give essentially the same results if I use a CEM Discovery (for microwaving) as opposed to using a hot plate? Also, what size (nm) do the dots usually come out using this method? Finally, can I use an Atomic Force Microscope to characterize them (which I am trained to use), or would you suggest a better method for characterization of size (besides obvious visual spectrum of light emission)? Ok, interrogation over, thank you!
+Adam Sciencepants I have a hard time imagining how you could possibly use AFM on a liquid sample. Maybe some kind of laser diffraction ?
+Quentin Alexandre well my thought was to suspend it with a PDMS gel suspension. ..just a thought, but I'll just do florescent spectrometry in the mean time
He's growing CdSe particles which have interesting light based properties! :)
You make science awesome :D
I'm curious as to the longevity of the reaction, and I suspect if you use even a florescent UV bulb that you will get spot heating of the mixture which will cause it head toward the red end of the spectrum over time. Also, a large enough quantity to make a lamp is going to cost you a lot more than just buying some florescent dye.
That was really cool, wayyy over my head, but enjoyable regardless haha. My chemistry experience ends with high school chemistry, but I still find it interesting and fun to watch :)
This was awesome!
this is amazing!
this is fascinating :)
I love the way that nor heat, nor cold at extreme temperatures affects the glass beakers and test tubes... Glass FOR THE WIN
I love Nurd Rage's videos mostly for the fact that I have to look up stuff I may not understand. Why can't learning in school be this fun!?
this is mind blowing chemistry :O but its fun to do it :D
I see. Thank you. Now, I would like to ask you a few more things: 1) You used selenium - can sulphur be used instead? 2) Could any other metal used instead of cadmium? 3) Which other chemicals act like this? Which can form quantum dots? Do all chemical in some ways act like this? 4) Is it necessary to use organic chemicals? How about Na2Se + CdCl2? Would not it do in non-concetrated solution just the same effect? Thank you very much.
I did almost this exact experiment in my second year university nanoscience class. We then used flourescence spectroscopy to examine them. Really cool experiment. I added the trioctylphosphine too quickly to the selenide solution and it exploded so we lost most of the sample.
another great video thank you
I wished for a quantum dot video. :) And then you did one... Have you measured the size distributions on them?
Thanks for the valuable info....but i don't know how the quantum dots will enhance the photovoltaic cells?.
Is it by converting the IR light into different spectrum so it reduces the heat and so the temp ceoffecient becomes better????
about time you made another video !! :)
at room temperature the reaction stops and the oleic acid surrounds the particles like a coating and prevents them from aggregating.
very nice videos, thanks alout, my follow is 100%! I wanna make some quantum dots for myself, but i want it without cadmium Selenide, you got any idea? I dont want this toxic metal!
Selenium, my favourite element. Try making iron, copper, molybdenum or lead selenide nanoparticles/quantum dots they all have interesting electrochemical properties.
I love chemistry!
@dragonfly111cute
i can't post links , i get about blank page when i do . just click onto my picture & look for videos from the scottish government about ocean wave action generators by oyster & aquamarine .
they REMOVED all my main channel comments + every thing I've shared from u, cute
@jotore hmm I wonder why that is?
@dragonfly111cute
a compliment in reverse ;)
@jotore hehe
The Thought Emporium - 2012-05-07
Not gonna lie, I've been looking forward to this video for a long time. I was going to attempt this myself but I decided that my lab isn't yet at the stage where this is feasible. I'll be making other nano particles to add to my collection, but these are still out of reach for the time being. Thanks for the awesome video. Even though it's not something the home chemist can really do (mostly due to the danger level), it's still a beautiful synthesis.