Photoinduced charge separation reactions of J-aggregates coated on silver nanoparticles.
The photochemistry of cyanine J-aggregates on the surface of colloidal Ag nanoparticles is reported. The photochemistry is initiated through ultrafast photoexcitation of the plasmon band in Ag nanoparticles, producing an enhanced near-field that interacts with the J-aggregate monolayer. Through transient absorption spectroscopy, we show that photoexcitation of the plasmon in Ag nanoparticles leads to exciton dynamics that differ strongly from J-aggregates alone or for J-aggregate monolayers on bulk metal surfaces. Specifically, charge-separated states with a lifetime of approximately 300 ps between the J-aggregate and Ag colloid are formed. The reduction of the Ag nanoparticles is shown to be a multielectron process.
Hranisavljevic
Jasmina
J
Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439-4831, USA.
Dimitrijevic
Nada M
NM
Wurtz
Gregory A
GA
Wiederrecht
Gary P
GP