Control the Single-, Two-, and Three-Photon Excited Fluorescence of Atomically Precise Metal Nanoclusters

It remains challenging to control the single-, two-, and three-photon excited fluorescence of metal nanoclusters. In this work, the control over the non-linear optics of metal nanoclusters as single-, two-, and three-photon excited fluorescence has been accomplished via exploiting the solvent effect. An emissive nanocluster, Au9Ag6((SPhOMe)-O-t)(4)(DPPOE)(3)Cl-3, was synthesized and structurally determined. The solvent effect can not only control the fluorescence of this nanocluster, but more significantly, it can also regulate the photoluminescence nature of the cluster as single-, two-, and three-photon excited fluorescence. We concluded that the increased solution polarity, improved dipole moment, enlarged HOMO-LUMO energy gap, and reduced solution viscosity of the cluster in solutions endow them with excellent high-order multiphoton excited fluorescence. The results provide an intriguing cluster template that enables us to manipulate the linear and nonlinear optics at the atomic level.

Automated summary

Control over the single-, two-, and three-photon excited fluorescence of metal nanoclusters has been achieved by exploiting the solvent effect. A luminous nanocluster was synthesized and its structure was determined. The results demonstrate that the solvent effect can not only control the fluorescence of the nanocluster, but also regulate its photoluminescence nature as single-, two-, and three-photon excited fluorescence.