| 1. |
- Gryszel, Maciej, et al.
(författare)
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Water-Soluble Cationic Perylene Diimide Dyes as Stable Photocatalysts for H2O2 Evolution
- 2023
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Ingår i: ChemPhotoChem. - : WILEY-V C H VERLAG GMBH. - 2367-0932. ; 7:9
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic generation of hydrogen peroxide, H2O2, has gained increasing attention in recent years, with applications ranging from solar energy conversion to biophysical research. While semiconducting solid-state materials are normally regarded as the workhorse for photogeneration of H2O2, an intriguing alternative for on-demand H2O2 is the use of photocatalytic organic dyes. Herein we report the use of water-soluble dyes based on perylene diimide molecules which behave as true molecular catalysts for the light-induced conversion of dissolved oxygen to hydrogen peroxide. In particular, we address how to obtain visible-light photocatalysts which are stable with respect to aggregation and photochemical degradation. We report on the factors affecting efficiency and stability, including variable electron donors, oxygen partial pressure, pH, and molecular catalyst structure. The result is a perylene diimide derivative with unprecedented peroxide evolution performance using a broad range of organic donor molecules and operating in a wide pH range.
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| 2. |
- Lee, Ji-Eun, et al.
(författare)
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Structure-Property Relationship of Perylene Bisimide Macrocycles Probed by Atomic Force Microscopy and Single-Molecule Fluorescence Spectroscopy
- 2013
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 7:6, s. 5064-5076
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Tidskriftsartikel (refereegranskat)abstract
- Properties of a series of acetylene-linked perylene bisimide (PBI) macrocycles with different ring size composed of three to six PBI dyes were investigated by atomic force microscopy (AFM) and single-molecule fluorescence spectroscopy in a condensed phase. it was demonstrated that the structures of PBI cyclic arrays (CNs, N = 3, 4,5, and 6) become distorted with increasing the ring size through molecular dynamic (MD) simulations (PM6-DH2 method) and AFM height images of CNs on highly ordered pyrolytic graphite (HOPG) surface. The MD simulations showed that only C5 and C6 rings are highly flexible molecules whose planarization goes along with a significant energetic penalty. Accordingly, both molecules did not show ordered adlayers on a HOPG surface. In contrast, C3 and C4 are far more rigid molecules leading to well-ordered hexagonal (C3) and rectangular (C4) 20 lattices. At the single-molecule level, we showed that the fluorescence properties of single CNs are affected by the structural changes. The fluorescence lifetimes of CNs became shorter and their distributions became broader due to the structural distortions with increasing the ring size. Furthermore, the CNs of smaller ring size exhibit a higher photostability and an efficient excitation energy transfer (EET) due to the more well-defined and planar structures compared to the larger CNs. Consequently, these observations provide evidence that not only PBI macrocycles are promising candidates for artificial light-harvesting systems, but also the photophysical properties of CNs are strongly related to the structural rigidity of CNs.
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| 3. |
- Merdasa, Aboma, et al.
(författare)
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Single Levy States-Disorder Induced Energy Funnels in Molecular Aggregates
- 2014
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 14:12, s. 6774-6781
-
Tidskriftsartikel (refereegranskat)abstract
- Using fluorescence super-resolution microscopy we studied simultaneous spectral, spatial localization, and blinking behavior of individual 1D J-aggregates. Excitons migrating 100 nm are funneled to a trap appearing as an additional red-shifted blinking fluorescence band. We propose that the trap is a Frenkel exciton state formed much below the main exciton band edge due to an environmentally induced heavy-tailed Levy disorder. This points to disorder engineering as a new avenue in controlling light-harvesting in molecular ensembles.
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