Researchers in Korea have developed a new temperature sensing platform based on graphene oxide (GO). The sensor uses GO’s functionality as an efficient Förster resonance energy transfer (FRET) acceptor to deliver a fast optical on-off signal in response to temperature change.
The article describes how the scientists functionalised GO sheets with thermally-responsive triblock copolymers for the first time. The triblock copolymer brush was designed to contain a component for covalent grafting to GO, a thermally-responsive component and a fluorescent component. At elevated temperatures, the thermally-responsive component (poly(N-isopropylacrylamide) undergoes a conformational change that reduces the distance between the fluorophore and GO. This quenches the photoluminescence (PL) of the flurophore component.
The scientists tested a dispersion of the functionalised GO sensing platform in water. PL spectra showed a decrease in intensity as the temperature was increased. A marked decrease in PL intensity was evident at temperatures above 32 oC, demonstrating an on-off switching behaviour of the sensor. The functionalised graphene oxide composites demonstrated excellent stability in water, opening up the possibility for their use as optical indicators of temperature change in biologically and environmentally compatible sensing systems.
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Efficient temperature sensing platform based on fluorescent block copolymer-functionalized graphene oxide
Bumjoon Kim, Hyunseung Yang and Kwanyeol Paek