Details

Autor(en) / Beteiligte

• Fennel, Franziska
• Gershberg, Jana
• Stolte, Matthias
• Würthner, Frank

Titel

Fluorescence quantum yields of dye aggregates: a showcase example based on self-assembled perylene bisimide dimersElectronic supplementary information (ESI) available: Synthesis and characterization of PBI 2, aggregation studies for PBI 2, details on fluorescence quantum yield determination and instrument calibration, UV/Vis absorption and emission spectra of PBI 1 and PBI 2. See DOI: 10.1039/c7cp07778e

Erscheinungsjahr

2018-03

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Constituting an intermediate state of matter between molecules and solid state materials, dye aggregates can give important insights into functional properties. Despite the importance of fluorescence for many applications, it turns out that the conventional methods for quantum yield determination are not applicable to dye aggregates and so far no method has been introduced for the accurate determination of the fluorescence quantum yields of dye aggregates. Here we suggest two measurement routines for the quantum yield determination of strongly absorbing dye aggregates. Both methods provide the quantum yield of the aggregated species without the necessity of reaching a fully aggregated state, which is particularly important for the most common case imparted by the low association constants of π-π-stacking interactions. The routines are experimentally validated with two perylene bisimide dyes whose self-assembly is driven by the concerted interplay of hydrogen bonding and π-π-stacking interactions, leading to structurally well defined co-facially stacked dimers at intermediate concentrations and a further growth into larger H-aggregates at a higher concentration. Compared to other H-aggregates relatively high fluorescence quantum yields of up to 28% are found for both the co-facially stacked dimers and the larger H-aggregates. Two measurement approaches for the precise quantum yield determination of supramolecular aggregates in highly concentrated solutions are presented and experimentally tested for an emissive perylene bisimide H-type aggregate with a quantum yield of 28%.