Panchromatic Chromophore Mixtures in an AlPO4-5 Molecular Sieve: Spatial Separation Effects and Energy Transfer Cascades

• Published in: Advanced functional materials Vol. 14; no. 3; pp. 269 - 276
• Main Authors: Ganschow, M., Hellriegel, C., Kneuper, E., Wark, M., Thiel, C., Schulz-Ekloff, G., Bräuchle, C., Wöhrle, D.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2004; WILEY‐VCH Verlag
• Subjects: Charge transfer; Chromophores; Encapsulation; Single crystals
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200304462

Dye‐loaded AlPO4‐5 single crystals were prepared by microwave‐assisted hydrothermal synthesis from a batch, containing a mixture of three chromophores (Coumarin 40, Rhodamine BE50, and Oxazine 1) differing in their absorption range, molecular dimensions, and solubilities. Confocal fluorescence images reveal a spatial separation effect of the dye molecules, where the slimmer, more‐soluble dye molecule (Coumarin 40) is uniformly distributed in the body of the single crystal, and the bulky and/or less‐soluble ones (Rhodamine BE50, Oxazine 1) are situated in distinct domains. Visible spectra show good panchromatic absorption of visible light. Fluorescence lifetime measurements indicate the presence of an energy transfer cascade of the entirely fixed dye molecules from Coumarin 40 to Oxazine 1. The transfer mechanism is predominantly radiative. Energy transfer between different dyes in a molecular sieve (as shown in the Figure) is studied. Coumarin 40, Rhodamine BE50, and Oxazine 1 were incorporated in one step during hydrothermal synthesis of AlPO4‐5. The incorporation of dyes absorbing and emitting light at different energies enables a good panchromatic uptake of visible light. The predominant energy transfer mechanism is radiative.