Tuning Optical Limiting of Heterosized AuNPs and Fullerene by Countable Electrochemical Assembly

Tuning optical limiting was achieved based on the nanostructural and synergistic effects of heterosized gold nanoparticles and fullerene on electrochemical assembly. In particular, with thicknesses of 200, 1, and 10 nm, heterosized AuNP multilayers with periodical pairs of layers present a superior threshold of 0.59 J cm^-2 to monosized AuNP films with the values of 0.89-2.55 J cm^-2, which was further significantly enhanced by the introduction of C₇₀ with a significant threshold drop from 0.43 to 0.13 J cm^-2, indicating that the reverse saturable absorption of C₇₀ had a key contribution compared to the free carrier absorption of AuNPs. This paper not only demonstrates that the hybrid engineering of heterosized AuNPs into an identical film is an effective way to enhance the optical limiting but also indicates that the reverse saturable absorption of C₇₀ is superior to free carrier absorption of AuNPs in optical limiting in AuNPs and C₇₀ hybrid films.