Importance of double-resonance effects in two-photon absorption properties of Au₂₅(SR)₁₈⁻

Abstract

We show that double-resonance effects for Au25(SR)18 – are less pronounced and do not lead to significantly enhanced two-photon absorption cross-sections.

Rationale Strategy to Tune the Optical Properties of Gold Catenane Nanoclusters by Doping with Silver Atoms

“…Two effects might explain this decrease: (i) structural changes of the Ag-doped Au10SG10 nanoclusters into more symmetrical structures (since second harmonic generation is only allowed for non-centrosymmetric structures) as compared to undoped nanoclusters and/or (ii) resonance effects between OPA and TPA states. 11,43 Since we have confirmed previously that catenane structures remain preserved upon silver doping, hypothesis (i) can be excluded, although the exact position of silver atoms in the catenane structure may affect the symmetry of the structure. Furthermore, the calculated first hyperpolarizabilities β for the [5,5] catenane structure, see Table S1 in SI for Au10SG10, Au9AgSG10 and Au7Ag3SG10 are in good agreement with the experimental values.…”

Enhanced two-photon absorption of ligated silver and gold nanoclusters: theoretical and experimental assessments

“…Note, in the frame of the damped response theory, that the two-photon transition moments remain finite and may better describe the doubleresonance effect. 66 However, conceptual conclusions can be drawn using the theoretical investigations on TPA crosssections.…”

Observation of a new type of aggregation-induced emission in nanoclusters

“… 1 – 16 Among these interesting physical/chemical properties, photo-luminescence (PL) represents one of the most fascinating features owing to the low toxicity, good photostability, and high biocompatibility of NCs. 1 , 2 , 8 , 17 – 24 Although several luminescent NCs have been reported, 8 , 18 , 21 – 31 most of them exhibit lower quantum yields (QYs) compared with other fluorescent nanomaterials (such as lanthanide nanoparticles, 32 organic dyes 33 and quantum dots 34 ), which severely impedes extensive application of fluorescent NCs in biological and sensing fields. Several strategies have been developed to enhance the PL QY of NCs, and they can be mainly classified into the following three categories: (1) tailoring the capping ligands of NCs (in terms of controlling the ligand to metal charge transfer (LMCT) process); 8 , 35 – 37 (2) controlling the metal composition in the NC kernel; 21 , 22 , 26 , 28 , 29 , 38 and (3) aggregation-induced emission (AIE) from non- or weakly luminescent metal NCs (or complexes).…”