title: Tuning Ag29 nanocluster light emission from red to blue with one and two-photon excitation.
abstract: We demonstrate that the tuning of the light emission from red to blue in dihydrolipoic acid (DHLA) capped Ag29 nanoclusters can be trigged with one and two photon excitations. The cluster stoichiometry was determined with mass spectrometry and found to be Ag29(DHLA)12. In a detailed optical investigation, we show that these silver nanoclusters exhibit a strong red photoluminescence visible to the naked eye and characterized by a quantum yield of nearly ∼2% upon one-photon excitation. In the nonlinear optical (NLO) study of the properties of the clusters, the two-photon excited fluorescence spectra were recorded and their first hyperpolarizability obtained. The two-photon absorption cross-section at ∼800 nm for Ag29(DHLA)12 is higher than 10(4) GM and the hyperpolarizability is 106 × 10(-30) esu at the same excitation wavelength. The two-photon excited fluorescence spectrum appears strongly blue-shifted as compared to the one-photon excited spectrum, displaying a broad band between 400 and 700 nm. The density functional theory (DFT) provides insight into the structural and electronic properties of Ag29(DHLA)12 as well as into interplay between metallic subunit or core and ligands which is responsible for unique optical properties.
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Russier-Antoine
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Franck
authors.initials: F
authors.lastname: Bertorelle
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Ramzi
authors.initials: R
authors.lastname: Hamouda
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Driss
authors.initials: D
authors.lastname: Rayane
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Dugourd
authors.affiliation: Center of excellence for Science and Technology-Integration of Mediterranean region (STIM) at Interdisciplinary Center for Advanced Sciences and Technology (ICAST), University of Split, Meštrovićevošetalište 45, HR-2100 Split, Republic of Croatia and Faculty of Science, University of Split, Teslina 12, HR-2100 Split, Republic of Croatia.
authors.forename: Željka
authors.initials: Ž
authors.lastname: Sanader
authors.affiliation: Center of excellence for Science and Technology-Integration of Mediterranean region (STIM) at Interdisciplinary Center for Advanced Sciences and Technology (ICAST), University of Split, Meštrovićevošetalište 45, HR-2100 Split, Republic of Croatia and Department of Chemistry, Humboldt Universitatzu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
authors.forename: Vlasta
authors.initials: V
authors.lastname: Bonačić-Koutecký
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Brevet
authors.affiliation: Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France. rodolphe.antoine@univ-lyon1.fr.
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Antoine