Hi everyone, long time forum reader here that just registered.
I'm writing this post to share the success I've had in making ZnS:Cu, or copper doped zinc sulfide.
It's a phosphor that emits a green light when excited with UV light or an electron beam.
The preparation procedure is here (yes, yet another youtube channel)
Perhaps even more interesting, the preparation procedure that I followed is documented in the book "Inorganic Phosphors" by W. Yen and M. Weber. The
book is quite dry, resembling more a lab notebook, but it contains hundreds of phosphor recipes, and hasn't been mentioned on this forum yet. XeonTheMGPony - 3-2-2019 at 07:35
Very nice video, guy deserves more subs, look forward to see what he does with it.fusso - 3-2-2019 at 09:01
GREAT setup for heating small amount of stuff in inert atmosphere!beta4 - 3-2-2019 at 15:22
I'm glad you liked the video, XeonTheMGPony.
I'm currently waiting for some ITO coated conductive glass to arrive from china. When it arrives, I'll try to make a small EL display and see how it
goes.
fusso, the tube furnace is a design of mine. I've taken inspiration from Doug's Lab furnace, but one main requirement was minimizing cost. To be
honest, I wasn't sure I'd be able to make something as sensitive to impurities as a phosphor, so I was looking for a cheap feasibility check.
Just some more info if someone wants to replicate my setup: I bought 5 quartz tubes from deschem for ~20€, enough fire bricks to make four of these
furnaces for another 5€, and the argon cylinder and regulating valve for 20€ each. I already had the gas torch.CharlieA - 3-2-2019 at 16:49
If I ever get a "round-2-it", I may try making some to dope alumina or silica gel plates for TLC. Thanks for the link. CharlieXeonTheMGPony - 4-2-2019 at 04:56
What was the IR sensitive phosphor they used for testing remote control IR transmitters?beta4 - 4-2-2019 at 12:45
I recall that some long afterglow phosphors can be "charged" with UV light, and be made to release the stored energy and light up under IR light.
The book I referenced lists one such phosphor: ZnS:Pb,Cu
The preparation is very similar to the one in my video (inert atmosphere, 1100°C firing temperature), but requires to add ~1.65mg of lead nitrate
instead of the ammonium chloride.
I also found (in the same book) a few "upconversion" phosphors able to convert infrared to visible, but don't seem very amateur friendly to make. One
is made of 25% molar ErCl3, the rest being BaCl2, but is hygroscopic and destroyed by moisture. The others are even worse as are based on fluorides.
[Edited on 4-2-2019 by beta4]Ozone - 4-2-2019 at 13:03
Interesting stuff, that. I've attached a .pdf demonstrating the properties of commercial pumped IR phosphors. It doesn't provide any compositional
information, but does show what you can get out of them. Also, they rotate the stuff in the beam to minimize saturation.
I wonder why the argon shield works at all, because I would think that through diffusion, the argon will escape. That the argon is heavier than air
doesn't matter too much when it comes to inhibiting diffusion. At least, that's my experience with diffusion. (And I didn't see you close the ends of
the tubes attached to the quartz heating tube.)
Does it boil down to a matter of good timing? I.e. the diffusion speed being slow enough to allow for 10 minutes of heating without the copper
oxidising? beta4 - 13-2-2019 at 12:07
From what I read, doping of crystalline materials is affected by the atmosphere used during the reaction.
In the phosphors book, each phosphor recipe includes an atmosphere recommendation.
Some recipes just say to do the firing in air, so I guess that if any other atmosphere is recommended, there has to be a reason.
However, it may not mean that it absolutely does not work unless the proper atmosphere is used.
This leaves two possibilities:
- either the small openings of the tube coupled with the fact that the firing is done immediately after the Ar filling limits diffusion
- or a little bit (or a lot) of air does not affect the preparation of ZnS:Cu
- or both
To know for sure we need a phosphor that absolutely does not work when fired in air, but works when fired with the tube filled with Ar in the way I've
done so far.
I may have a good candidate, but no promises on when I can do the tests (I'm busy with my day job).Tsjerk - 13-2-2019 at 12:34
Very nice video!
I do think you are a bit hard to understand when you are standing in a certain position compared to your camera, sometimes it is fine, sometimes you
sound different. It may be worse when you stand behind your camera, or maybe it is the distance.
But keep up the videos, I at least subscribed. stibium - 17-1-2021 at 11:46
Hi everyone,
I have had some success synthesizing phosphorescent materials based on alkaline earth sulfides and zinc sulfide.
I synthesized the sulfide according to the chemical reaction:
2 MCO3 + 3 S = 2 MS + SO2 + 2 CO2
M = Ca, Sr, Ba or Zn
It is also possible with this other reaction:
4 MO + 4 S = 3 MS + MSO4
Phosphorescence is achieved by adding very small amounts of some metal that acts as an activator (Cu, Bi, Ag, Eu ...). The activator metal is added in
the form of a salt dissolved in water (I used nitrates). I prepared very dilute solutions and added the necessary amount of activator according to
each recipe. I used the amounts of activator described in these articles:
Alkaline earth sulfide phosphorescent pigments: https://patents.google.com/patent/US2544507
Calcium sulfide Europium doped: https://www.researchgate.net/publication/244688077_Enhanceme...
"Inorganic Phosphors" by W. Yen and M. Weber
It is also necessary to add a small amount of a low melting point salt (flux), which serves to distribute the activator more evenly in the sulfide. I
mainly use Na2SO4 and NaCl as fluxes, but Na2CO3 can also work.
Basically I followed this procedure:
I made a suspension in water by intimately mixing the alkaline earth carbonate, sulfur, flux and the activator salt (drops of solution). I heated this
mix to evaporate the water, and put the dry mix into a covered crucible placed on a gas burner for 30 minutes, or until the evolution of gas ceases.
Then I placed the crucible covered in an electric oven maintained for 30 minutes at 950ºC. Then I took it out to cool down quickly.
There are a number of rules to follow to be successful:
It has to start from very pure chemicals. Iron is a phosphorescence killer, amounts of even one part per million damage phosphorescence.
The amount of activator must be very small.
The mixture of all the products must be very intimate and uniform.
The crucible must be covered to avoid oxidation of the sulfide by air. The ideal would be to heat the products in a reducing atmosphere (sulfur vapor,
SH2, or CS2).
The calcination temperature should be high but not excessive (900 to 1000 ºC).
Once the phosphorescent material has been obtained, it must be kept in tightly closed containers. CaS, SrS and BaS are chemically unstable in
atmosphere. With moisture in air, these three compounds will be degraded and release SH2.
Phosphorescence can be activated by daylight, UV light, or a white LED flashlight in less than 1 minute. and the duration of the phosphorescence is
between 30 minutes and several hours (depending on each case).
Pictures:
From left to right:
SrS:Eu
CaS:Eu,Ce,Tm
SrS:Bi
CaS:Bi,Ag
ZnS:Cu
Bedlasky - 17-1-2021 at 13:25
Stibium: Very nice results! I recently read about Ln3+/Yb3+ dopped CaWO4 phosphors and I plan to make these.Bezaleel - 18-1-2021 at 06:04
Great work, stibium! I love phosphors, but I cannot make them because I do not have a furnace. The ones in your pictures are fantastic.vano - 18-1-2021 at 06:52
I bought a samarium today. I am going to use it in other things, but if you have information on how to make a similar material with samarium, I would
be happy to try it.ChemTalk - 23-1-2021 at 09:11
Stibium, thanks so much for posting your report and the links to the articles. These are the best results I've seen from this procedure which is known
to be difficult. Will you try any more combinations?
Vano, I look forward to seeing what you make with your samarium.vano - 23-1-2021 at 10:14
I am mainly interested in divalent compounds. Unlike other lanthanides this compounds are stable.
[Edited on 23-1-2021 by vano]Bedlasky - 23-1-2021 at 18:34
Vano: I wouldn't say that Sm(II) is stable (at least in aqueous solution). It's very strong reducing agent, it's impossible to make it in aqueous
solution because it reacts with water, you must work in THF. It can be easily make by reaction between metallic Sm and I2 in THF. There are more
solvents for SmI2 than THF. YbI2 can be made similarly. Both compounds have similar properties, but because SmI2 is less stable, it have stronger
reducing properties and it work better than YbI2. I send you some materials about SmI2 and YbI2 in U2U. I discussed lanthanide chemistry with Fery
recently and we talked about using SmI2 in organic reactions.
Btw: Not just samarium is stable in II oxidation state. Ytterbium and europium are even more stable (Eu(II) can be made even in aqueous solution).
[Edited on 24-1-2021 by Bedlasky]beta4 - 24-1-2021 at 13:18
Nice phosphors stibium!
I'm going back to making phosphors as well. After finding a way to purify sulfur and silver I finally made ZnS:Ag with an acceptable brightness (will
make a video about it soon).
I also ordered SrCO3, Pr(NO3)3, TiO2 to try making some red phosphorescent materials (SrTiO3 : Pr3+ from the book Inorganic
Phosphors). After that, I'll try mixing them to get white, which seems something you can already try.
[Edited on 24-1-2021 by beta4]
[Edited on 24-1-2021 by beta4]stibium - 24-1-2021 at 14:40
Stibium, thanks so much for posting your report and the links to the articles. These are the best results I've seen from this procedure which is known
to be difficult. Will you try any more combinations?
Vano, I look forward to seeing what you make with your samarium.
I have synthesized another phosphorescent material:
BaS: Bi (golden yellow phosphorescence)
I bought a samarium today. I am going to use it in other things, but if you have information on how to make a similar material with samarium, I would
be happy to try it.
I found 2 articles about use of samarium in some phosphorescent materials:
A possible use of samarium in pyrotechnics:
Samarium powder sprayed over a flame produces pink sparks.
Here you can see 2 interesting articles about colored sparks with samarium and other rare earth metals:
Nowhere near the quality of the stuff stibium produced but this is something i made. Using same method as beta4:s linked video, but torched in a tube
and wihout protective atmosphere
[Edited on 24-1-2021 by RustyShackleford]vano - 25-1-2021 at 07:22
Nowhere near the quality of the stuff stibium produced but this is something i made. Using same method as beta4:s linked video, but torched in a tube
and wihout protective atmosphere]
ZnS:Mn in my experience is one of the hardest. Likely because of Fe impurities in Mn which are very hard to get rid of. The optimal concentration of
Mn is also much higher than Cu or Ag, around 1% molar, so you're adding even more Fe to the mix.
The best attempt I made is still much dimmer than ZnS:Cu and the powder is visibly textured with bright and dark spots, unlike the copper and silver
ones which are uniformly bright.
My advice since you already have the setup to make phosphors is to try again with copper, you won't regret it. Housane - 8-2-2021 at 05:29
For anyone that wants here is the book mentioned above
For anyone that wants here is the book mentioned above
What a find! Thanks for posting it here.Dr. Noreen Wakeman - 15-2-2021 at 07:51
I've found many phosphor dyes just by using a black light on different markers I have. My original
intention was to use it as a homemade TLC plate backing with the intent of allowing me to observe the different components without wasting acid. If
you aren't trying to make invisible ink, I recommend this process as you can easily remove the ink from these markers by taking out the ink reservoir
and putting it in boiling 0.01M NaCl water. The ink will flow out of the foam reservoir and into the water thus giving you the ink.stibium - 7-4-2021 at 11:23
I found a link with a lot of pictures, ideas, projects and recipes about fluorescent and phosphorescent materials:
I've found two papers claiming to have made photoluminescent Cu and Mn doped ZnS nanoparticles using room temperature wet chemical methods...
*without* firing in a furance. They only dried the material at 70C in a hot air oven.
Low temperatures, no inert atmospheres. Seems too good to be true!
Extracts from the "materials and methods" sections:
Manganese doped:
" Chemical precipitation technique used in this study has the distinct qualities such as low processing temperature (<100 °C), simplicity of
processing, low cost and high rate of powder collection. Synthesis of pure ZnS nanoparticles by wet chemical method was reported by the authors
previously [21]. We followed the same procedure in the synthesis of manganese doped ZnS nanoparticles. Twenty five milliliter each of zinc acetate Zn
(CH3COO)2, MnCl2 and Na2S solutions in water were used for the preparation of Mn2+ doped ZnS nanoparticles. 0.001 M solution of MnCl2 was added drop
wise to 1 M zinc acetate Zn(CH3COO)2 solution. One molar Na2S solution was added drop wise with continuous stirring using magnetic stirrer. The
solution was stirred for 20 min keeping temperature constant. The resulting white colloidal suspension was filtered, and the filtrate was washed with
de-ionized water and dried by keeping in an oven at 70 °C for 1 day. Three samples were prepared at room temperature, 50 and 70 °C. "
Copper doped:
" ZnS:Cu nanoparticles have been prepared by chemical precipitation technique without any capping agent, similar to our previous work [29]. Cu doped
ZnS have precipitated from a mixture of zinc acetate [Zn (CH3COO)2] and copper nitrate [Cu(NO3)2] with sodium sulphide [Na2S] in water in ratio of 1:1
for Zn:S. The precipitate thus formed was filtered, washed with distilled water and dried by keeping in a hot air oven at 70 °C for 16 h. In this way
five samples were synthesised at room temperature with different Cu (0.0005, 0.001, 0.002, 0.003 & 0.004 M) concentrations. The same procedure was
also followed for the synthesis of all the ZnS:Cu nanoparticles at 50 °C, 70 °C and 90 °C keeping Cu concentration (0.001 M) same. "
I've also attached their original paper where they first synthesized (undoped) ZnS nanoparticles.
Attachment: bindu2015.pdf (819kB) This file has been downloaded 262 times
Attachment: bindu2012.pdf (668kB) This file has been downloaded 269 times
Attachment: bindu2021 (1).pdf (762kB) This file has been downloaded 281 timesNeal - 27-11-2022 at 12:35
I did not know polyurethane can phosphoresce, or fluoresce. I recall polyurethane is something you can put on wood to prevent sunlight changing the
color.
And I was recently aware that certain rocks can fluoresece.knowledgevschaos - 17-8-2023 at 21:00
Phosphorescent calcium sulfide can be made through heating 1 part crushed oyster shells with 2 parts sulfur. Apparently oyster shells are better than
pure calcium carbonate, because minerals and impurities in the shells act to dope the calcium sulfide. I haven't been able to make this yet but I'm
looking forward to trying. https://sciencenotes.org/make-glow-dark-powder-oyster-shells...
