Effect of Silver Alloying on the Vibrational Dynamics of Rod-Shaped Gold Nanoclusters

Abstract

Doping and alloying are effective strategies to improve the performance of metal nanoclusters, including photoluminescence and catalysis. The effect of doping on the electronic properties has been intensively investigated by experimental and theoretical methods, while the effect of foreign atoms on the mechanical properties of metal nanoclusters remains largely unknown. Here, we investigated the effect of silver alloying on the mechanical properties of rod-shaped gold nanoclusters by comparing the coherent vibrational dynamics of rod-shaped Au 25 and Ag x Au 25−x (x ≤ 13). In both nanoclusters, we observed significant coherent vibrations in their transient absorption dynamics. The coherent vibrations exhibit a frequency of 0.9 THz and 0.65 THz for Au 25 and Ag x Au 25−x (x ≤ 13), respectively, which are assigned to extension vibration modes of two rods. A detailed analysis of the coherent vibration indicates that the amplitude of the excited-state absorption is modulated in these two NCs. These results provide new insights into the photophysics of alloy metal nanoclusters.

Atomically Precise Silver Clusters Stabilized by Lacunary Polyoxometalates with Photocatalytic CO2 Reduction Activity

“…To further understand the electronic interaction between {Ag 24 } 14+ cluster and {Si 2 W 18 O 66 } POM ligands, we probed the excited state dynamics by performing time‐resolved femtosecond transient absorption (fs‐TA) spectroscopy [17] . Upon excitation at 380 nm, the excited state absorption (ESA) band around 450 nm decays to give rise to the ESA band around 550 nm in the first 1 ps (Figures 2b,c).…”

“…[11c,g] To further understand the electronic interaction between {Ag 24 } 14 + cluster and {Si 2 W 18 O 66 } POM ligands, we probed the excited state dynamics by performing time-resolved femtosecond transient absorption (fs-TA) spectroscopy. [17] Upon excitation at 380 nm, the excited state absorption (ESA) band around 450 nm decays to give rise to the ESA band around 550 nm in the first 1 ps (Figures 2b,c). With near gap excitation at 600 nm, the spectral evolution in the initial 1 ps can also be observed (Figures 2e,f), which indicates that the rapid state to state relaxation does not arise from hot electron cooling.…”

Dual-quartet phosphorescent emission in the open-shell M1Ag13 (M = Pt, Pd) nanoclusters

“…Data reductions and absorption corrections were performed using the SAINT and SADABS programs, respectively. Fs-TA measurements were performed on a home-built setup and ns-TA measurement were performed using a commercial spectrometer (Nano100, Time-Tech Spectra) 53 .…”

Robust vibrational coherence protected by a core–shell structure in silver nanoclusters

“…18–20 Because coherence is an important property in other systems, and widely applied, the coherence of the metal NCs that are newly observed using broadband transient absorption (TA) spectroscopy have attracted great attention in recent years. 21–33…”