High Yield Synthesis and Quadratic Nonlinearities of Gold Nanoprisms in Solution: the Role of Corner Sharpness

Size and shape of noble metal nanoparticles have a major influence on their linear and second order nonlinear properties. Among these nanostructures, acentric objects are expected to display high quadratic nonlinear responses. In this work, a single – step growth of gold nanoprisms (GNPs) was achieved by seedless growth. Their second harmonic response has been investigated experimentally and theoretically with edge length ranging from 40 to 116 nm and for different curvature radii at corners. Their first hyperpolarizabilities β have been measured by Harmonic Light Scattering at 1064 nm. Their calculated and experimental β values are found to display, not only a linear dependence with the surface area as reported for other metallic nanoparticle shapes, but also a strong influence of their corner sharpness on the corresponding nonlinearities. Such high experimental and theoretical β values of GNPs are mainly assigned to the sharpness of tips.