engleski

Sub-100 nanometer silver doped gold–cysteine supramolecular assemblies with enhanced nonlinear optical properties

The ability of gold( I ) thiolates to self- assemble into supramolecular architectures opens the route for a new class of nanomaterials with a unique structure–optical property relationship. However, for a confirmed structure–optical property relationship, control of the supramolecular architectures is required. In this work, we report a simple synthesis of sub- 100 nanometer gold– cysteine and silver doped gold– cysteine supramolecular assemblies. We explore in particular silver-doping as a strategy to enhance the optical properties of these supramolecular assemblies. By an accurate characterization of as- synthesized supramolecular nanoparticles, we have been able to measure for the first time, their absolute two- photon absorption cross- section, two- photon excited fluorescence cross- section and first hyperpolarizabilities at different near-IR wavelengths. Huge values are obtained for silver doped gold–cysteine supramolecular assemblies, as compared to their corresponding undoped counterpart. In addition, we employ DFT and TD-DFT methods to study the geometric and electronic structures of model gold–cysteine and silver doped gold–cysteine compounds in order to address the structure and linear/nonlinear optical properties relationship. The aim is to gain insights into the origin of the nonlinear optical enhancement of silver-doped gold supramolecular assemblies.

gold nanoclusters ; nanowires ; linear spectra ; nonlinear spectra ; TD-DFT. DFT ; nanoscale ; OPA, TPA ; silver doping

This article is part of the themed collection: 2019 PCCP HOT Articles