Carbon dots have the potential to display interesting luminescence properties that are influenced by chemical composition. In this work, fluorescent nitrogen-doped carbon dots (CDs) were synthesized using either citric acid (CA) or malic acid (MA) as the carbon precursors and using ethylenediamine (EDA) as the nitrogen precursor/cross-linker. Additionally, phosphoric acid (PA) was used as a doping agent for each type of carbon dots to test the effect of incorporating phosphorous into the CDs nanostructure. Thus, four kinds of doped CDs were obtained, named as CA-CDs, CA-P-CDs (CAPs), MA-CDs, and MA-P-CDs (MAPs). Quantum yield and fluorescence lifetime analysis indicated that doping of up to c.a.10 wt.% phosphorus did not induce a significant change in terms of CDs photoluminescence performance. The N, P co-doped CDs, however, were observed to be more photostable than the N-doped CDs under 350 nm UV exposure. Lastly, to assess the possibility that luminescent CDs may be a replacement for toxic heavy metal-based quantum dots, the bacterial toxicity of these doped CDs was tested using Shewanella oneidensis MR-1 as a model microorganism. In fact, they exhibited no toxicity in most cases, and in some cases even facilitated bacterial growth, making CDs an eco-friendly fluorescent material with a wide range of potential applications.

Synthesis of N, P co-doped amorphous carbon dots and their toxicological impact on Shewanella oneidensis MR-1 bacteria

253rd National Meeting (2017)

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