Sciencemadness Discussion Board

Replacing indium tin oxide with graphene sheet

vmelkon - 16-6-2015 at 11:31

Cool stuff
http://phys.org/news/2010-02-super-material-cheaper-fully-re...

+ I had read a group doing research (2 years ago) on another replacement that was made of a Al2O3 layer but the problem was that it was air sensitive and degraded over time.

Graphene sheet might be the permanent solution.

battoussai114 - 19-6-2015 at 15:12

What about Aluminum Zinc Oxide? It seems like a rather cheaper alternative, even if compared with graphene....

papaya - 20-6-2015 at 03:14

Al2O3 is conductive ?

battoussai114 - 20-6-2015 at 11:47

Quote: Originally posted by papaya  
Al2O3 is conductive ?

AFAIC it isn't. Probably there's a dopant involved.

Zombie - 20-6-2015 at 12:16

I looked into graphene oxide from a supplier that posted here. As I remember it was 4k a kilo.
We keep seeing all these claims that graphene will change the future but not at it current pricing.

battoussai114 - 20-6-2015 at 20:07

Quote: Originally posted by Zombie  
I looked into graphene oxide from a supplier that posted here. As I remember it was 4k a kilo.
We keep seeing all these claims that graphene will change the future but not at it current pricing.

Indeed.
I kinda hoped for the prices to drop with all those surfactant assisted liquid phase expholiation ideas that popped around, but seems it didn't....

WGTR - 21-6-2015 at 17:17

It's possible to form graphene nano-flake suspensions by direct exfoliation of graphite in DMF in an ultrasonic bath. The solution can be centrifuged to separate the heavier, un-exfoliated flakes, and then the supernatant filtered on PTFE. The residue agglomerates on the filter paper, but doesn't significantly restack to graphite. For this reason, the residue can be re-dispersed in solvents that would not ordinarily allow the direct exfoliation of graphite, such as ethanol or water. These types of dispersions, especially in water, are not stable, and usually agglomerate and settle out over several hours. I think that partial restacking to graphite is occurring in solution, as re-dispersal of the precipitates is much less efficient after agglomeration initially occurs.

Even though the dispersions are not stable for long periods in ethanol, the low boiling point allows the exfoliated material to be dispersed, and then sprayed onto hot surfaces and flash-dried. The DMF, with its high boiling point, is recycled. Small quantities of DMF can be used to exfoliate an unlimited amount of graphite.

Flake graphene doesn't have anywhere near the conductivity that CVD graphene does, due to the defects caused by the flake edges. It is cheaper, though. I think we are just seeing the beginning of solvent-exfoliated graphene being made commercially available. I don't think it's hit the market quite yet.

[Edited on 6-22-2015 by WGTR]

battoussai114 - 22-6-2015 at 18:19

I'm probably wrong, but I think the idea to make flake graphene more useful is converting it to graphene oxide and then sintering it (can't rementer if it's MW, light or heat sintering)...

IrC - 22-6-2015 at 23:48

I think the approach using 13.56 MHZ RF is interesting and looks like a good idea for amateur experimentation.


Attachment: Cardinali.pdf (1.1MB)
This file has been downloaded 1137 times

IrC - 26-6-2015 at 21:45

Graphene-based magnetic sensor 100 times more sensitive than an equivalent silicon device

http://www.nanowerk.com/nanotechnology-news/newsid=40599.php

This link describes a use for Graphene which might be an interesting project for someone here.

j_sum1 - 26-6-2015 at 22:52

Obligatory link.
http://www.compoundchem.com/2015/06/23/graphene/

The point made is that graphene tech keeps on promising but is yet to deliver on the promise.

I wonder if it ever will.

battoussai114 - 27-6-2015 at 19:17

Anyone here tried making graphene by CVD? seems that method for deposition on copper foil isn't way too fancy for the sort of humble lab I've got. Sure a controlled methane + hydrogen atmosphere isn't something I'd want close to a super heated piece of metal unless I can be reaaaaly sure there won't be oxygen getting in from some failure on my design.... still it seems doable.

Also, I recently got a beefy motor from an old laundry machine and I'll probably have a ball mill ready for doing liquid phase exfoliation in the next weeks. :D

Oscilllator - 27-6-2015 at 21:04

Quote: Originally posted by battoussai114  
Anyone here tried making graphene by CVD? seems that method for deposition on copper foil isn't way too fancy for the sort of humble lab I've got. Sure a controlled methane + hydrogen atmosphere isn't something I'd want close to a super heated piece of metal unless I can be reaaaaly sure there won't be oxygen getting in from some failure on my design.... still it seems doable.

I think cleaning the copper adequately might be the problem there. If the surface has to be smooth, pure copper then it could be really difficult. Perhaps sanding under oil with fine sandpaper followed by rinsing the copper under your previously prepared inert atmosphere.

Zombie - 28-6-2015 at 04:45

I've looked at a lot of methods to either acquire or make my own graphine. There is nothing happening that makes it viable. Same for supplies of GO. There is nothing viable.

Kind of like making nitric acid from beans. It's just not practical.

IrC - 28-6-2015 at 16:17

If you replace the i with an e so it is spelled Graphene, a search on this site yields this result. Also search pyrolytic graphite, you will get a large number of threads. I have read that these materials are being tested for ability to store hydrogen.

http://www.sciencemadness.org/talk/viewthread.php?tid=30172#...