Berlin 2018 – scientific programme

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BP: Fachverband Biologische Physik

BP 9: Postersession I

BP 9.27: Poster

Monday, March 12, 2018, 17:30–19:30, Poster A

Comparing the properties of graphene quantum dots prepared in a microwave and graphene quantum dots prepared on a hot plate — •Alexandra Steina, Stefan Fasbender, and Thomas Heinzel — Experimental Condensed Matter Physics, Heinrich-Heine-University Dusseldorf

Fluorescent graphene quantum dots (GQDs) are prepared by the method of Wu et al. [1] via hydrothermal treatment (3 hours, 180° C) of citric acid and dicyandiamide on a hot plate (hGQDs). The fluorescence properties of these GQDs (quantum yield: 29 %, emission maximum around 450 nm at 360 nm excitation) are compared to GQDs prepared in a microwave oven (mGQDs) using the same recipe and the same synthesis temperature. The duration of the microwave synthesis is varied and the highest fluorescence quantum yield amounts to 29 % after a synthesis time of 2 minutes. The mGQDs show a nearly identical fluorescence spectrum compared to the hGQDs with the same emission maximum around 450 nm at 360 nm excitation. XPS data reveals that hGQDs are composed of 52 % carbon, 23 % nitrogen and 25 % oxygen whereas mGQDs are composed of 43 % carbon, 26 % nitrogen and 31 % oxygen.

[1] Wu et al., Nanoscale, 2014, 6, 3868