Investigation of the Co-Dependence of Morphology and Fluorescence Lifetime in a Metal-Organic Framework

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 12; no. 27; pp. 3651 - 3657
• Main Authors: Schrimpf, Waldemar, Ossato, Giulia, Hirschle, Patrick, Wuttke, Stefan, Lamb, Don C.
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 01.07.2016; Wiley Subscription Services, Inc
• Subjects: Correlation; correlative microscopy; Dependence; electron microscopy; Fluorescence; fluorescence lifetime imaging; Heterogeneity; Metal-organic frameworks; Morphology; Nanotechnology; phasors; Porous materials; Quenching; Scanning electron microscopy; Service life assessment; phasors; correlative microscopy; electron microscopy; fluorescence lifetime imaging; metal-organic frameworks
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201600619

Porous materials, due to their large surface‐to‐volume ratio, are important for a broad range of applications and are the subject of intense research. Most studies investigate the bulk properties of these materials, which are not sensitive to the effect of heterogeneities within the sample. Herein, a new strategy based on correlative fluorescence lifetime imaging and scanning electron microscopy is presented that allows the detection and localization of those heterogeneities, and connects them to morphological and structural features of the material. By applying this method to a dye‐modified metal‐organic framework (MOF), two independent fluorescence quenching mechanisms in the MOF scaffold are identified and quantified. The first mechanism is based on quenching via amino groups, while the second mechanism is influenced by morphology. Furthermore, a similar correlation between the inherent luminescence lifetime and the morphology of the unmodified MOF structure is demonstrated. A novel approach to elucidate the structural, functional, and morphological properties of (in)organic materials using correlative fluorescence lifetime image microscopy and scanning electron microscopy is presented. Using this method, a correlation between the morphology and the fluorescence lifetime in a metal‐organic framework (MOF) is shown. Additionally, two quenching mechanisms of fluorescein in this MOF are identified and quantified.