Housane - 17-6-2020 at 14:17
Today I managed to make green carbon quantum dots by dissolving 3g of sucrose in 10ml of water and 1ml of 30% HCl was added to make it acidic. It was
then heated at 80-90C for 10 minutes and the water was allowed to evaporate. After 5 mins the solution turned yellow and it got steadily darker. After
the 10 mins a distinctly sweet our could be smelt.
It was take off the heat and allowed to cool. The remaining black solution was dissolved in 150ml of water and then filtered, a dark filtrate was
collected. This was made neutral by addition of NaOH. These are quantum dots but to see them clearly i diluted them. In the pictures the range on the
lower level is 2 fully concentrated then 5 vials going from 25% to 5% in 5% increments. Feel free to ask any questions. The glow is poor as the light
is a cheap UV invisible ink pen, I will do better pictures on request.
Regards
Housane
[Edited on 18-6-2020 by Housane]
More pictures
Housane - 17-6-2020 at 14:21
Ubya - 17-6-2020 at 17:26
i have a request for you, could you check in a few months/a year if they still fluoresce the same?
i made some blue quantum dots via the hydrothermal method (pretty much the same thing you did but in a closed vessel and at 180°C instead of 90) a
year and a half ago, and now the solution fluoresces green and it is much much fainter, i suspect that with time the nano particles aggregate
somewhat, i would be interested to know how long it takes for yours
Housane - 18-6-2020 at 00:05
Yeah sure,I will do an update in a year or so
draculic acid69 - 18-6-2020 at 03:00
This sounds a lot like making levulinic acid.
mackolol - 18-6-2020 at 04:07
And what's the chemistry behind it. What chemical is formed by heating sugar with HCl and then neutralising it?
Housane - 18-6-2020 at 05:14
The idea is you are breaking down the carbon and then slowly reforming it in such a way that lots of tiny particles are formed and this is what
changes the colour of the UV light. Thought emporium has a video about them. The acid slightly alters this. Others colours should be possible in Basic
solutions and the colour may change depending on what acid is used, more exeprimatation I need to do
Housane - 18-6-2020 at 13:13
I think I have just made yellow quantum dots, I will post again when the solution is concentrated enough to get a good picture
wg48temp9 - 14-8-2020 at 14:21
While looking for a wiring diagram for my dishwasher, which I did not find, but I did find a paper describing how to make Doped/Co-Doped Carbon
Quantum Dots. I thought others may find it useful so I am posting it in this thread.
Attachment: carbon-05-00024-v2.pdf (5.1MB)
This file has been downloaded 279 times
Housane - 11-10-2020 at 06:58
Ubya, I have just checked them and both the green and the yellow glow exactly the same as before