title: Direct laser writing of photostable fluorescent silver nanoclusters in polymer films.
abstract: Metal nanoclusters consist of a few to a few hundred atoms and exhibit attractive molecular properties such as ultrasmall size, discrete energy levels, and strong fluorescence. Although patterning of these clusters down to the micro- or nanoscale could lead to applications such as high-density data storage, it has been reported only for inorganic matrices. Here we present submicron-scale mask-free patterning of fluorescent silver nanoclusters in an organic matrix. The nanoclusters were produced by direct laser writing in poly(methacrylic acid) thin films and exhibit a broadband emission at visible wavelengths with photostability that is superior to that of Rhodamine 6G dye. This fabrication method could open new opportunities for applications in nanophotonics like imaging, labeling, and metal ion sensing. We foresee that this method can be further applied to prepare other metal nanoclusters embedded in compositionally different polymer matrices.
authors.affiliation: Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland.
authors.forename: Puskal
authors.initials: P
authors.lastname: Kunwar
authors.forename: Jukka
authors.initials: J
authors.lastname: Hassinen
authors.forename: Godofredo
authors.initials: G
authors.lastname: Bautista
authors.forename: Robin H A
authors.initials: RH
authors.lastname: Ras
authors.forename: Juha
authors.initials: J
authors.lastname: Toivonen
keywords: metal nanoclusters; optical lithography; photobleaching; photoluminescence; photostability; polymer