The third order nonlinear optical properties of graphene oxide–zinc (II) naphthalocyanine hybrids and amino graphene oxide–zinc (II) naphthalocyanine hybrids

Novel tetracarboxylic zinc naphthalocyanine-graphene oxide (ZnNcC4-GO) and tetracarboxylic zinc naphthalocyanine-amino graphene oxide (ZnNcC4-NGO) hybrids have been prepared with a covalent functionalization method. A series of characterizations have been used to prove the structures of ZnNcC4-GO and ZnNcC4-NGO hybrids. The third order nonlinear optical properties were investigated using the Z-scan technique at 532 nm with 4 ns laser pulses. Either ZnNcC4-GO or ZnNcC4-NGO exhibited much larger nonlinear optical absorption coefficients than GO and ZnNcC4 as a result of the covalent link between GO and ZnNcC4. ZnNcC4-NGO hybrids perform the enhanced NLO properties than ZnNcC4-GO, attributed to the increased excited state absorption from the extended sp2 carbon configurations of the NGO moiety in ZnNcC4-NGO hybrids along with the partial reduction of NGO nanosheets, and the stronger PET/ET process between NGO and ZnNcC4. Moreover, the Z-scan curve of ZnNcC4-NGO shows a deeper RSA valley and the larger β value compared to that of ZnPcC4-NGO because the π-conjugated system of ZnNcC4 is larger relative to that of ZnPcC4. Scheme of GO, NGO, ZnNcC4-GO and ZnNcC4-NGO synthesis proceduresZnNcC4-NGO hybrids perform the enhanced NLO properties than ZnNcC4-GO,and the larger β value compared to that of ZnPcC4-NGO because the π-conjugated system of ZnNcC4 is larger relative to that of ZnPcC4. [Display omitted]