Graphene Quantum Dots (GQD) are one of the youngest and consequently less explored fluorescent nanoparticles in comparison to other carbon types and semiconducting inorganic quantum dots. [1-2] All available in the UK and Ireland. Despite the fact that they are new to the nanoparticle family, GQDs have already attracted great interest because of their biocompatibility and unique physical properties. The main advantage of GQDs is their non-toxic property in a wide variety of analytical and biomedical processes. This is not the case for some more popular CdSe and PbS based quantum dots which have excellent optoelectronic properties However, the intrinsic toxicity of heavy metals is a main barrier for these materials in many biomedical related applications. 
GQDs are characterized by a well-defined structure of nanosheets made up of sp2 carbons. These particles typically have dimensions in the size below 20nm, exhibit high volume surface ratio and generally show a strong absorbance in UV region. The basic absorption spectra of GQDs show a prominent peak at about 230 nm, which is assigned to the π → π* excitation of the π bonds of aromatic carbon-carbon double bond of the benzene ring. The preparation method and functionalization or modification of the edges of the particles can introduce further absorption features and affect the photo luminescence. In addition, GQDs exhibit size-dependent UV–Vis absorption spectrum due to the quantum confinement effect.
Strem Chemicals, in collaboration with Dotz Nano Ltd, offers aqua-green (06-0330 & 06-0332), blue (06-0334 & 06-0336) and cyan (06-0340) luminescent GQDs. These nanodots have a narrow particle size distribution and diameters of less than 5 nm. For more detailed information about our GQDs’ quantum yield, maximum excitation wavelength, maximum emission and FWHM please review their individual technical notes.
Another key characteristic of these products is that they resist photobleaching, a known and problematic trait of fluorescent spectroscopy. The low cost is an additional benefit.
GQD properties like chemical inertness, excellent photo stability, solubility in various solvents (including water) and low cytotoxicity make them appropriate candidates for research processes in a variety of fields from energy technology [5-6], bio sensing to biomedical diagnosis, therapy [7-8] and agriculture. 
Products mentioned in this blog and related products:
For additional details please see our Graphene Quantum Dots Literature Sheet or the individual item technical notes. Email us at enquiries @www.strem.co.uk or phone 01223 873028