Design Strategy and Structure-Property Relation for Enhanced Two-Photon Absorption in Ligated Metal Nanoclusters

A complete understanding of the two-photon absorption (TPA) process is a key issue for the rational design of optimal two-photon chromophores. For this purpose, structure–property relationship of molecular TPA is of great importance. In this chapter, taking example of push–pull molecules, we will describe first how theoretical results can be used to obtain an extensive comprehension of the physics underlying the two-photon process and its amplitude. This will serve to propose an exploratory root for novel chemical engineering leading to further enhancement of TPA in liganded silver and gold quantum clusters. Using small ligated silver nanoclusters as test systems, we illustrate how theoretical approaches together with experimental findings can contribute to the understanding of structure–property relationships that might ultimately guide nanocluster synthesis.