Chemistry has great potential as a means to control the electronic properties of the two-dimensional carbon material graphene. Electron transfer between graphene and adsorbed molecules can increase its conductance by shifting the Fermi level to a region of the band structure with a greater density of states. We use micro-Raman spectroscopy to measure the surface adsorption and electron-transfer dynamics between graphene and I2 molecules in solution. Solvated I2 molecules can adsorb onto graphene via weak van der Waals forces. We measure the degree of charge-transfer between these adsorbed molecules and graphene as a function of I2 concentration and solvent identity. Concentration dependent measurements in cyclohexane generate a solution-phase Langmuir isotherm that we use to calculate equilibrium constants for I2 surface adsorption on graphene. We observe that complex-forming solvents such as dichloromethane and water result in weaker graphene doping than cyclohexane.

Raman spectroscopic study of solvent-mediated electron-transfer chemical doping of graphene

249th National Meeting (2015)

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