Synthesis of photoluminescent N doped and S doped carbon graphene quantum dots with modified optical properties

Graphene quantum dots (GQDs) are a new class of materials that have replaced the conventional bimetallic dots with their unique properties. In the present study GQDs, N doped GQDs (N-GQDs) and S doped GQDs (S-GQDs) are synthesized by in-situ one step method of pyrolysis of citric acid (bottom up technique). The fabrication of florescent GQDs and doped GQDs with heteroatom N and S are evidently supported with transmission electron microscopy (TEM) and FT-IR. The mechanism of the photoluminescence in these quantum dots is investigated thorough the photoluminescence spectroscopy (PL) which was further reinforced by the electrochemical impedance spectroscopy (EIS) and with cyclic voltammetry. N-GQDs shows blue colored emission while S-GQDs shows relatively longer wavelength yellow green colored emission. Emission from the defective surface sites of the doped GQDs was confirmed from the proposed mechanism of PL of these dots.

Automated summary

Graphene quantum dots and doped graphene quantum dots were synthesized by a one-step method and characterized using microscopy and spectroscopy. The study found that nitrogen-doped graphene quantum dots emitted blue light, while sulfur-doped graphene quantum dots emitted yellow-green light.