Russier-Antoine Isabelle, Bertorelle Franck, Hamouda Ramzi, Rayane Driss, Dugourd Philippe, Sanader Željka, Bonačić-Koutecký Vlasta, Brevet Pierre-François, Antoine Rodolphe
Institut Lumière Matière, UMR CNRS 5306 and Université Claude Bernard Lyon 1, Université de Lyon, 69622 Villeurbanne cedex, France.
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.
Nanoscale. 2016 Feb 7;8(5):2892-8. doi: 10.1039/c5nr08122j.
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.
我们证明，在二氢硫辛酸（DHLA）包覆的Ag29纳米团簇中，通过单光子和双光子激发可触发其发光从红色到蓝色的调谐。通过质谱法确定了团簇的化学计量，发现其为Ag29（DHLA）12。在详细的光学研究中，我们表明这些银纳米团簇表现出肉眼可见的强烈红色光致发光，单光子激发时的量子产率接近2%。在对团簇性质的非线性光学（NLO）研究中，记录了双光子激发荧光光谱并获得了它们的第一超极化率。Ag29（DHLA）12在~800 nm处的双光子吸收截面高于10（4）GM，在相同激发波长下超极化率为106×10（-30）esu。与单光子激发光谱相比，双光子激发荧光光谱出现强烈的蓝移，在400至700 nm之间显示出一个宽带。密度泛函理论（DFT）深入了解了Ag29（DHLA）12的结构和电子性质，以及金属亚基或核心与配体之间的相互作用，这是其独特光学性质的原因。
