Zeolitic Imidazolate frameworks (ZIFs) have been demonstrated as promising light harvesting and photocatalytic materials for solar energy conversion. To facilitate their application in photocatalysis, it is essential to develop a fundamental understanding of their light absorption properties and energy transfer dynamics. In this work, we report distance-dependent energy transfer dynamics from a molecular photosensitizer (RuN3) to ZIF-67, where the distance between RuN3 and ZIF-67 is finely tuned by depositing an ultrathin Al 2 O 3 layer on the ZIF-67 surface using an atomic layer deposition (ALD) method. We show that energy transfer time decreases with increasing distance between RuN3 and ZIF-67 and the Förster radius is estimated to be 14.4 nm.
Photoinduced interfacial charge separation dynamics in zeolitic imidazolate framework
Owing to their porous structure and tunable framework, zeolitic imidazolate frameworks (ZIFs) have garnered considerable attention as promising photocatalytic materials. However, little is known regarding their photophysical properties. In this work, we report the photoinduced charge separation dynamics in a ZIF-67 thin film through interfacial electron transfer (ET) to methylene blue (MB + ) via ultrafast transient absorption spectroscopy. We show that the ET process occurs through two distinct pathways, including an ultrafast (<200 fs) process from the [Co II (mim) 2 ] units located on the surface of ZIF-67 film that are directly in contact with MB + and a relatively slower ET process with a 101.4 ps time constant from the units in the bulk of the film that were isolated from MB + by the surface units. This first direct evidence of the ET process from ZIF-67 to electron acceptor strongly suggests that ZIF materials may be used as intrinsic photocatalytic materials rather than inert hosts.
- Award ID(s):
- 1654140
- Publication Date:
- NSF-PAR ID:
- 10082404
- Journal Name:
- Physical Chemistry Chemical Physics
- Volume:
- 20
- Issue:
- 21
- Page Range or eLocation-ID:
- 14884 to 14888
- ISSN:
- 1463-9076
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Publisher's Version of Record
- https://doi.org/10.1039/C8CP02078G
