▎ 摘　　要

Based on the graphene nanosheets (GNSs) with full armchair edge, the second order nonlinear optical properties of these GNSs in different shapes with good chemical stability were modulated by introducing two, three and four azulenes. The result shows that the number of azulene defects plays a dominant role in the second order nonlinear optical responses of these GNSs. The GNSs with four azulenes have large second order nonlinear optical responses, among which AP-4a has the largest static first hyperpolarizability (, 230387.70 a. u., 2260.42 a. u. per heavy atom). In addition, the nanosheet shape also has a certain effect. The azulene moieties not only induce charge distribution polarization of GNSs, but also dominate in the major electron transitions with important contribution to the nonlinear optical responses. Azulene as a functional unit of carbon-based nanomaterials significantly improves the photoelectric properties of carbon-based nanomaterials, and this finding provides practical strategies and useful information for future carbon-based nonlinear optical materials design.