TY  - JOUR
A1  - Dong, Hailong
A1  - Kuzmanoski, Ana
A1  - Wehner, Tobias
A1  - Mueller-Buschbaum, Klaus
A1  - Feldmann, Claus
T1  - Microwave-assisted polyol synthesis of water dispersible red-emitting Eu\(^{3+}\)-modified carbon dots
JF  - Materials
N2  - Eu\(^{3+}\)-modified carbon dots (C-dots), 3–5 nm in diameter, were prepared, functionalized, and stabilized via a one-pot polyol synthesis. The role of Eu\(^{2+}\)/Eu\(^{3+}\), the influence of O\(_2\) (oxidation) and H\(_2\)O (hydrolysis), as well as the impact of the heating procedure (conventional resistance heating and microwave (MW) heating) were explored. With the reducing conditions of the polyol at the elevated temperature of synthesis (200–230 °C), first of all, Eu\(^{2+}\) was obtained resulting in the blue emission of the C-dots. Subsequent to O\(_2\)-driven oxidation, Eu\(^{3+}\)-modified, red-emitting C-dots were realized. However, the Eu\(^{3+}\) emission is rapidly quenched by water for C-dots prepared via conventional resistance heating. In contrast to the hydroxyl functionalization of conventionally-heated C-dots, MW-heating results in a carboxylate functionalization of the C-dots. Carboxylate-coordinated Eu\(^{3+}\), however, turned out as highly stable even in water. Based on this fundamental understanding of synthesis and material, in sum, a one-pot polyol approach is established that results in H\(_2\)O-dispersable C-dots with intense red Eu\(^{3+}\)-line-type emission.
KW  - carbon dot
KW  - europium
KW  - microwave
KW  - polyol
KW  - surface conditioning
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181674
VL  - 10
ER  -