Au-Ag nanoalloy molecule-like clusters for enhanced quantum efficiency emission of Er³⁺ ions in silica.
The occurrence of a very efficient non-resonant energy transfer process forming ultrasmall Au-Ag nanoalloy clusters and Er(3+) ions is investigated in silica. The enhancement of the room temperature Er(3+) emission efficiency by an order of magnitude is achieved by coupling rare-earth ions to molecule-like (Au(x)Ag(1-x))N alloy nanoclusters with N = 10-15 atoms and x = 0.6 obtained by optimized sequential ion implantation on Er-implanted silica. For comparison, AuN nanoclusters obtained by the same approach and with the same size and numerical density showed an enhancement by only a factor of 2 with respect to pure Er emission, demonstrating the beneficial effect of using nanoalloyed clusters. The temperature evolution of the energy transfer process is investigated by photoluminescence and exhibits a maximum efficiency at about 600 °C, where the clusters reach the optimal size and the silica matrix completely recovers the implantation damage. The nanoalloy cluster composition and size have been studied by EXAFS analysis, which indicated a stronger Ag-O interaction with respect to the Au-O one and a preferential location of the Ag atoms at the nanoalloy cluster surface.
Physics and Astronomy Department and CNISM, University of Padova, via Marzolo 8, I-35131 Padova, Italy. tiziana.cesca@unipd.it giovanni.mattei@unipd.it.
Tiziana
T
Cesca
Boris
B
Kalinic
Niccolò
N
Michieli
Chiara
C
Maurizio
Angela
A
Trapananti
Carlo
C
Scian
Giancarlo
G
Battaglin
Paolo
P
Mazzoldi
Giovanni
G
Mattei
D000497:Alloys; D004871:Erbium / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D049329:Nanostructures; D011789:Quantum Theory; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
D000497:Alloys; D012834:Silver; D006046:Gold; D012822:Silicon Dioxide; D004871:Erbium