A review on characterization of carbon quantum dots

Abstract

Carbon quantum dots (CQDs) are a new blooming carbon containing nanoparticles having size of less than 10 nm. They have wide range of application in the field of sensing of inorganic analytes, bio sensing, cell imaging, studying biological processes in living cells and also for drug delivery. These nanoparticles of carbon are playing important roles due to their interesting qualities like small particle size, biocompatibility, fluorescing, etc. Sometimes it shows excitation wavelength dependent, which may be more than 100 nm, and sometimes excitation wavelength independent fluorescent property. CQDs are highly photo stable (stable for hours), compared to the conventional fluorescent semiconductor quantum dots. To apply such carbon quantum dots, it is necessary to characterize the CQDs first. Most of the time they are characterized by photophysical and structural property using UV-VIS spectroscopy, fluorescence spectrophotometry, FT-IR, XRD, XPS, Raman spectroscopy, TCSPC, HRTEM, etc. In this review article we demonstrate how these tools are used to characterize newly synthesized CQDs, monitor the synthesis process along with finding its application in numerous fields.