Chemically modified graphene oxide (GO) sheets exhibit three “fingerprinting” photoluminescent (PL) peaks, which originate from the σ* → n, π* → π and π* → n electronic transitions between the antibonding and the bonding molecular orbitals. The three PL peaks are associated with the C–OH, the aromatic C![[double bond, length as m-dash]](http://www.rsc.org/images/entities/char_e001.gif)
C and the CO functional groups in the GO sheets, respectively. The relative intensities of the three PL peaks are modulated by varying the oxygen-containing functional groups. The three PL emission peaks exhibit a red-shift with an increase in the excitation wavelength. The difference between the emission peak and the excitation wavelength shows a constant Stokes shift of 53.3 nm, 112.1 nm and 217.9 nm for the σ* → n, π* → π and π* → n transitions, respectively.
Journal of Materials Chemistry
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