Ligand-Core NLO-Phores

Overview & Synopsis

Functional ligand-protected noble metal cluster nanomaterials with enhanced two-photon absorption and two-photon excited emission may lead to new technologies for bio-imaging applications. In this article, I review experimental and theoretical methodologies allowing detailed investigation of two-photon absorption/emission properties of ligand-protected silver and gold metal clusters. This includes femtosecond two-photon excited fluorescence experimental setups and quantum chemical methodologies based on time-dependent density functional theory. I thoroughly analyze physical phenomena and trends leading to large two-photon absorption/emission responses of model nanoclusters focusing on the effects of the relaxation pathways in the linear and nonlinear optical regime, as well as strategies aiming at enhancing their two-photon emission responses.