Feb 22, 2011
Graphene hybrid advances solubility and fluorescence quenching
Huaqiang Cao and his colleagues at Tsinghua University, China, are investigating indolizine functionalized graphene (IMG) through a 1,3-dipolar cycloaddition to graphene with pyridinium ylide. Using this synthesis method, the team has obtained IMG with excellent solubility and fluorescence quenching effect. IMG can be completely dispersed in N,N-dimethylformamide (DMF) and ethanol for more than four months without obvious aggregation. The significant improvement in solubility was attributed to the modification of indolizing groups, which endows IMG with enhanced processability and points towards potential applications as a multi-functional graphene-based composite material. The fluorescence intensity of IMG is quenched by a factor of ~93.4% on indolizine under the same experimental conditions, showing that efficient energy transfer occurs along the indolizing/graphene interface. Combined with the excellent solubility as well as electronic properties of the graphene skeleton, IMG shows potential commercial uses in fabricating electrochemical and photochemical devices.
As shown in the figures above, the synthesis of IMG is composed of two steps: reduced graphene oxide reacted with pyridinium salt in DMG solvent, followed by reacting with triethylamine. The corresponding inset shows photographs of 1 mg·ml–1 IMG dispersed and left to stand in DMF and ethanol for more than four months. Data on the right hand side reveal the fluorescence quenching effect of IMG.
The researchers anticipate that the synthesis method will be broadly available commercially due to its easy preparation and wide range of applications in electrochemical and photochemical devices. The group has collaborated with researchers at Nanjing University, China, and hopes that photochemical devices can be prepared by using the hybrid graphene materials.
"This hybrid graphene material has great potential for solar light harvesting applications since you can obtain ~93.4% fluorescence quench efficiency," Cao told nanotechweb.org.
Full details can be found in the journal Nanotechnology.
About the author
The research work was carried out at Tsinghua University, Beijing, China. Dr Huaqiang Cao is a research scientist (associate professor) at Tsinghua University. His research interests include synthesis of functional nanomaterials with superhydrophobicity, retardant effects, photocatalytic activity, as well as applications in biomedicine, supercapacitors and secondary batteries (Ni/MH and lithium-ion batteries). Currently he is exploring a brand new approach to inorganic functional nanomaterials, especially graphene-based hybrid materials in energy storage devices.