Mild bottom-up synthesis of carbon dots with temperature-dependent fluorescence

Bottom-up methods allowing the preparation of carbon dots (CDs) with favorable attributes are highly desirable. Herein, we report the mild bottom-up synthesis of CDs towards temperature sensing. Five kinds of CDs with blue or green fluorescence were synthesized in water or tetrahydrofuran (THF) under moderate conditions (normal pressure, 50 similar to 95 degrees C), with use of carbonyl compounds as carbon sources, such as acetylacetone (AA), cyclohexanone (CH), 2-hydroxy-2-methylpropiophenone (HM), glutaric dialdehyde (GD), and salicylaldehyde (SA). Typically, with use of acetylacetone (AA) as carbon sources, CDs were synthesized at 95 degrees C in water in the presence of zinc chloride and 1, 2-dichloroethane. The synthesis, characterizations, and optical properties of AA-derived CDs were thoroughly investigated. The resultant CDs exhibit green photoluminescence (PL) at 520 nm with absolute PL quantum yield (QY) of 21%. Moreover, the PL intensity proportionally depends on temperature in the range 150-360 K, which makes AA-derived CDs potentially useful for temperature sensing.

Automated summary

The mild bottom-up synthesis of carbon dots (CDs) for temperature sensing using carbonyl compounds as carbon sources was reported, resulting in CDs with green fluorescence. The acetylacetone (AA)-derived CDs showed green photoluminescence with absolute PL quantum yield (QY) of 21%, and their PL intensity was found to be proportional to temperature, making them potentially useful for temperature sensing.