Controlling the fluorescence and room-temperature phosphorescence behaviour of carbon nanodots with inorganic crystalline nanocomposites

• Published in: Nature communications Vol. 10; no. 1; pp. 206 - 13
• Main Authors: Green, David C., Holden, Mark A., Levenstein, Mark A., Zhang, Shuheng, Johnson, Benjamin R. G., Gala de Pablo, Julia, Ward, Andrew, Botchway, Stanley W., Meldrum, Fiona C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.01.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/146; 147/28; 639/301/119/995; 639/301/54; 639/638/440/527; 639/925/357; Anions; Carbon; Carbonates; Cations; Chemical synthesis; Crystal structure; Crystallinity; Diodes; Electron transitions; Embedding; Fluorescence; Humanities and Social Sciences; multidisciplinary; Nanocomposites; Organic chemistry; Organic light emitting diodes; Oxalates; Phosphorescence; Photodynamic therapy; Photoluminescence; Room temperature; Science; Science (multidisciplinary); Sulfates
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-08214-6

There is a significant drive to identify alternative materials that exhibit room temperature phosphorescence for technologies including bio-imaging, photodynamic therapy and organic light-emitting diodes. Ideally, these materials should be non-toxic and cheap, and it will be possible to control their photoluminescent properties. This was achieved here by embedding carbon nanodots within crystalline particles of alkaline earth carbonates, sulphates and oxalates. The resultant nanocomposites are luminescent and exhibit a bright, sub-second lifetime afterglow. Importantly, the excited state lifetimes, and steady-state and afterglow colours can all be systematically controlled by varying the cations and anions in the host inorganic phase, due to the influence of the cation size and material density on emissive and non-emissive electronic transitions. This simple strategy provides a flexible route for generating materials with specific, phosphorescent properties and is an exciting alternative to approaches relying on the synthesis of custom-made luminescent organic molecules. Materials exhibiting room temperature phosphorescence (RTP) with short afterglow are desirable for bio-medical applications. Here the authors synthesise a library of compounds with tunable RTP properties, embedding carbon nanodots in non-toxic alkaline-earth carbonate, sulphate and oxalate hosts.