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Diazonium functionalized graphene: microstructure, electric, and magnetic properties
Ping Huang1, Long Jing, Huarui Zhu
1CAS Key Laboratory for Biomedical Effect of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Science, Beijing, China.
Accounts of Chemical Research
|November 13, 2012
Summary
Aryl diazonium functionalization of graphene creates semiconducting materials by controlling its electronic properties. This covalent chemistry approach offers a stable method to engineer graphene for electronic applications, overcoming its inherent lack of a bandgap.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Graphene's honeycomb lattice provides exceptional electronic properties like high carrier mobility.
- A key limitation for graphene in electronics is its zero energy bandgap.
- Covalent functionalization offers a controllable and stable method to modify graphene's electronic structure.
Purpose of the Study:
- To investigate the structural, electronic, and transport properties of nitrophenyl-diazonium-functionalized graphene.
- To explore the impact of aryl diazonium functionalization on graphene's bandgap and conductivity.
- To demonstrate the potential for creating semiconducting graphene through controlled chemical modification.
Main Methods:
- Synthesis of nitrophenyl-diazonium-functionalized graphene.
- Analysis of micromolecular and lattice structures using experimental techniques.
- Characterization of electronic band structure and electron transport properties.
- Theoretical calculations to model superlattice structures and their electronic properties.
Main Results:
- Nitrophenyl groups functionalize graphene inhomogeneously, slightly elongating the lattice spacing.
- Low functionalization decreases conductivity, while high functionalization increases it due to competing charge transfer and scattering effects.
- Functionalization breaks lattice symmetry, increasing carrier density but decreasing mobility.
- Ordered superlattices were observed, exhibiting semiconducting behavior with a bandgap of ~0.5 eV.
Conclusions:
- Aryl diazonium functionalization is a viable strategy to engineer graphene's electronic properties.
- This method can controllably introduce a bandgap, transforming graphene into a semiconductor.
- Asymmetric functionalization holds promise for developing ferromagnetic, semiconducting graphene for advanced electronic devices.
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