Abstract
Carbon‐based quantum dots (C‐QDs) were synthesized through microwave‐assisted carbonization of an aqueous starch suspension mediated by sulphuric and phosphoric acids. The as‐prepared C‐QDs showed blue, green and yellow luminescence without the addition of any surface‐passivating agent. The C‐QDs were further analyzed by UV−vis spectroscopy to measure the optical response of the organic compound. The energy gaps revealed narrow sizing of C‐QDs in the semiconductor range. The optical refractive index and dielectric constant were investigated. The C‐QDs size distribution was characterized. The results suggested an easy route to the large scale production of C‐QDs materials.