Photoemission mechanism of water-soluble silver nanoclusters: ligand-to-metal-metal charge transfer vs strong coupling between surface plasmon and emitters.
Using carboxylate-protected silver nanoclusters (Ag-carboxylate NCs) as a model, we separately investigated the contribution of the ligand shell and the metal core to understand the nature of photoluminescence of Ag NCs. A new Ag(0)NCs@Ag(I)-carboxylate complex core-shell structural model has been proposed. The emission from the Ag-carboxylate NCs could be attributed to ligand-to-metal-metal charge transfer from Ag(I)-carboxylate complexes (the oxygen atom in the carboxylate ligands to the Ag(I) ions) to the Ag atoms and subsequent radiative relaxation. Additionally, we found that the emission wavelength of the Ag NCs depends on the excitation wavelength implying a strong coupling between surface plasmon and emitter in Ag NCs. The strong coupling between the surface plasmon and the emitter determines the quantum yield and lifetime. The emission mechanism of Ag NCs and its relation to the organic templates and metal cores were clearly clarified. The results should stimulate additional experimental and theoretical research on the molecular-level design of luminescent metal probes for optoelectronics and other applications.
State Key Laboratory of Precision Spectroscopy and ‡Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University , Shanghai 200062, P. R. China.
Yuting
Y
Chen
Taiqun
T
Yang
Haifeng
H
Pan
Yufeng
Y
Yuan
Li
L
Chen
Mengwei
M
Liu
Kun
K
Zhang
Sanjun
S
Zhang
Peng
P
Wu
Jianhua
J
Xu
D004553:Electric Conductivity; D007477:Ions; D008024:Ligands; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D012995:Solubility; D020349:Surface Plasmon Resonance; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D007477:Ions; D008024:Ligands; D014867:Water; D012834:Silver