Surface Plasmon-Coupled Emission of Rhodamine 110 Aggregates in a Silica Nanolayer

Abstract

First analysis of strong directional surface plasmon-coupled emission (SPCE) of ground-state formed intermolecular aggregates of Rhodamine 110 (R110) in silica nanofilms deposited on silver nanolayers is reported. Until now, the processes of energy transport and its trapping due to aggregate formation have not been studied in the presence of SPCE. A new approach to multicomponent systems with weakly and strongly fluorescent centers making use of fluorophore-surface plasmon interaction is presented. The analysis is based on comparison of experimental free-space emission spectra (F-SE), experimental SPCE with theoretical surface plasmon resonance spectra (SPR). It is shown that, due to the dispersion of SPCE, the detection of weak aggregate emission is straightforward if only the monomers and aggregates fluorescence spectra are somewhat spectrally shifted. SPCE studies confirmed the formation of weakly fluorescent higher order aggregates of R110 in silica films. The results indicate that the increase of energy transfer from monomers to aggregates is due to fluorophore-plasmon interaction.

The Luminescence of 1,8-Diazafluoren-9-One/Titanium Dioxide Composite Thin Films for Optical Application

“…Shortening of fluorescence lifetime with the increase in the dye concentration evidences the significant presence of aggregates, which can play a double role in the system: firstly, aggregates can act as perfect or imperfect traps for excitation energy transferred from monomers [2,12,[34][35][36][37][38][39] and, secondly, the aggregates at highest concentrations are likely to contribute to the fluorescence signal emitting short living fluorescence. A similar behavior has been previously observed and analyzed for several other dyes such as rhodamines and carbocyanines in polymers and hybrid matrices with the only difference that, in this work, the fluorescence spectral shift was found more pronounced, making those analyses more straightforward [4,39]. All of the results support the hypothesis that the increase of the aggregation degree was induced by the hydrogen bonds (O-H .…”

“…Therefore, one of the goals of this work was to study basic aggregate properties in the titanium dioxide thin film, which is important for its potential application, since the aggregation process can shorten the fluorescence decays and lifetimes of monomers. This is the case of many other molecular systems in which aggregates are formed [2][3][4][5][6], for example in some medical applications [7,8]. The knowledge of whether we are dealing with aggregate or monomer form at a given concentration of the active compound is vital as the actual form may alter the pharmacological activity of the compound as well as its ability to penetrate through biological membranes.…”

Local Dye Concentration and Spectroscopic Properties of Monomer–Aggregate Systems in Hybrid Porous Nanolayers

“…The absorption spectra were measured with Shimadzu 1650 PC spectrophotometer. The steady-state fluorescence spectra were measured with the spectrofluorometer especially dedicated for measurements of fluorescence charateristics of nanolayers and thin films 41. …”

New Core-Shell Nanostructures for FRET Studies: Synthesis, Characterization, and Quantitative Analysis

“…The measurement was carried out at 298 K using 1-cm-thick quartz spectrophotometric cuvettes in 2% ( v / v ) solution in DMF over the 200–800 nm range. The measurements of fluorescence spectra and fluorescence intensity decays were performed using a multifunctional pulsed spectrofluorometer constructed in our laboratory [ 40 ].…”