Synthesis and characterization of carbon quantum dots made from everyday products

Unpublised and non-submitted article made as part of a course on scientific approach and communication. 

The study of nanoparticles is a complex and prolific branch of molecular chemistry, with significant relevance to research in medicine, electronics, computing, and renewable energy. Carbon quantum dots (CQDs) are a specific type of carbon nanoparticle characterized by high stability, good electrical conductivity, and low toxicity. These structures can confine an electron, which can be excited to produce photoluminescence. Although nanoparticle synthesis may involve expensive reagents and complex processes, the luminescence of CQDs can be demonstrated and modified through a simple experiment using everyday products and household items, making it valuable for educational purposes. Following a theoretical overview of CQDs and their distinctive properties, a synthesis using citric acid (lemonade) and polyethylene glycol (SYSTANE™) is presented. This work also includes a protocol for characterizing the nanoparticles using absorption and emission spectroscopy, as well as nanoparticle tracking analysis (NTA). Finally, the experiment is extended to investigate the quenching of CQD luminescence through controlled additions of Fe²⁺ ions.