Tuning the Emission Color of Hydrothermally Synthesized Carbon Quantum Dots by Precursor Engineering

Abstract

Water-soluble, biocompatible, and high luminescence carbon quantum dots (CQDs) have been successfully synthesized from citric acid (CA) and ethylenediamine (EDA) using different approaches. Although the emission quantum yield of CQDs could be as high as 80%, their emission spectrum is usually dominated by surface fluorophore groups and maximized at about 450 nm. This paper examines the effects of acid and amine precursors on the photoluminescence (PL) of resulted CQDs by systematically comparing the optical properties of CQDs obtained from CA, PA (phthalic acid) with EDA, ANL (aniline). UV-vis and PL spectroscopic studies revealed that the absorption onset varied from 325 nm to 400 nm while PL maximum changed from 390 nm to 450 nm by engineering acid and amine precursors. The emission quantum yield was also changed from 9% to 70%, depending on the used acid-amine precursors. 

Keywords

Carbon quantum dots, hydrothermal synthesis, colour tuning, photoluminescence, acid, amine.

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