Researchers investigated the effect of UV irradiation on the nonlinear optical response (NLO) of graphene oxide (GO), fluorographene (GF), hydrogenated fluorographene (GFH), and graphene (G) dispersions.
In situ UV photoreduction enabled extensive modification of the degree of functionalization (i.e., oxidation, fluorination, and hydrogenation), effectively tuning the corresponding sp2/sp3 hybridization ratios. The nonlinear optical properties of the studied samples were determined using the Z-scan technique with visible (532 nm), and 4 ns laser excitation before and after UV irradiation and were found to change significantly.
More specifically, while the nonlinear optical response of GO increases with irradiation time, that of GF and GFH decreases monotonically. After more than an hour of UV irradiation, the nonlinear optical response of graphene dispersions remains unaffected. The current findings show that UV photoreduction can be an effective and simple strategy for controlling the nonlinear optical response of these graphene derivatives, resulting in derivatives with tailored responses that are more suitable for various photonic and optoelectronic applications.
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