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 (ZnNcC(4)-GO) and tetracarboxylic zinc naphthalocyanine-amino graphene oxide (ZnNcC(4)-NGO) hybrids have been prepared with a covalent functionalization method. A series of characterizations have been used to prove the structures of ZnNcC(4)-GO and ZnNcC(4)-NGO hybrids. The third order nonlinear optical properties were investigated using the Z-scan technique at 532 nm with 4 ns laser pulses. Either ZnNcC(4)-GO or ZnNcC(4)-NGO exhibited much larger nonlinear optical absorption coefficients than GO and ZnNcC(4) as a result of the covalent link between GO and ZnNcC(4). ZnNcC(4)-NGO hybrids perform the enhanced NLO properties than ZnNcC(4)-GO, attributed to the increased excited state absorption from the extended sp(2) carbon configurations of the NGO moiety in ZnNcC(4)-NGO hybrids along with the partial reduction of NGO nanosheets, and the stronger PET/ET process between NGO and ZnNcC(4). Moreover, the Z-scan curve of ZnNcC(4)-NGO shows a deeper RSA valley and the larger beta value compared to that of ZnPcC4-NGO because the pi-conjugated system of ZnNcC(4) is larger relative to that of ZnPcC4. (c) 2019 Elsevier Ltd. All rights reserved.