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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
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Effect of noncovalent basal plane functionalization on the quantum capacitance in graphene
Mona A Ebrish1, Eric J Olson, Steven J Koester
1University of Minnesota-Twin Cities , 200 Union Street SE, Minneapolis, Minnesota 55455, United States.
ACS Applied Materials & Interfaces
|June 5, 2014
Summary
Functionalizing graphene with specific molecules enhances its quantum capacitance. This improvement is key for developing advanced graphene-based wireless chemical and biological sensors.
Area of Science:
- Materials Science
- Nanotechnology
- Chemistry
Background:
- Graphene's tunable capacitance, owing to its concentration-dependent density of states, enables its use as a variable capacitor (varactor).
- This varactor property is crucial for developing sensitive wireless sensing applications.
- Surface functionalization is a known method to impart specific analyte sensitivity to graphene.
Purpose of the Study:
- To investigate the impact of noncovalent basal plane functionalization on the quantum capacitance of graphene.
- To explore the use of 1-pyrenebutanoic acid succimidyl ester and glucose oxidase for functionalization.
- To assess the performance of functionalized graphene in air for potential sensor applications.
Main Methods:
- Noncovalent functionalization of graphene basal plane using 1-pyrenebutanoic acid succimidyl ester and glucose oxidase.
- Measurement of quantum capacitance of functionalized graphene samples in air.
- Comparison of capacitance characteristics (Dirac point, maximum capacitance, tuning range) with vacuum conditions.
Main Results:
- Functionalized graphene samples exhibited a Dirac point similar to vacuum conditions when tested in air.
- Maximum capacitance increased compared to vacuum but remained similar to air, with enhanced quantum capacitance tuning.
- These effects are attributed to reduced surface doping and potential fluctuations, facilitated by H2O displacement and intercalation.
Conclusions:
- Noncovalent functionalization effectively modifies graphene's quantum capacitance, enhancing its performance in ambient conditions.
- The observed changes are linked to water molecule interactions with the functionalized graphene surface.
- This study highlights graphene's potential as a versatile platform for advanced wireless chemical and biological sensors.
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