There is a lot of companies selling GO in USA (like CheapTubes, Nanostructured and Amorphous Materials, etc.). But I think, you can find some sellers close to you: most likely, you have them in India: just browse on Internet.
In lab, handle with care: GO might be very dusty and all penetrating, depending on the brand. Preferably use a protecting mask and gloves.
You can buy it from Sigma-Aldrich, though it is little costly, you can go for it. Because you can not compromise in quality as your whole study depends on it.
And you better keep in dry and dust free area. Close the cap after the use.
There is a lot of companies selling GO in USA (like CheapTubes, Nanostructured and Amorphous Materials, etc.). But I think, you can find some sellers close to you: most likely, you have them in India: just browse on Internet.
In lab, handle with care: GO might be very dusty and all penetrating, depending on the brand. Preferably use a protecting mask and gloves.
Products from Sigma-Aldrich do not necessarily imply quality. The worst carbon nanotubes I used ever were precisely from Sigma-Aldrich. It is better to look for specialized companies. In addition to the product, they usually provide some important characterization (for example, SEM, TEM and Raman).
Graphnea is worth looking at also. If you think you might need a lot of material you may want to consider preparing GO yourself. There's a lot of literature out there and the preparation is relatively straightforward but does require equipment such as centrifuges etc, and ideally characterisation afterwards. Hope this helps!