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Wang L, Puodziukynaite E, Vary RP, Grumstrup EM, Walczak RM, Zolotarskaya OY, Schanze KS, Reynolds JR, Papanikolas JM. Competition between Ultrafast Energy Flow and Electron Transfer in a Ru(II)-Loaded Polyfluorene Light-Harvesting Polymer. J Phys Chem Lett 2012; 3:2453-2457. [PMID: 26292132 DOI: 10.1021/jz300979j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This Letter describes the synthesis and photophysical characterization of a Ru(II) assembly consisting of metal polypyridyl complexes linked together by a polyfluorene scaffold. Unlike many scaffolds incorporating saturated linkages, the conjugated polymer in this system acts as a functional light-harvesting component. Conformational disorder breaks the conjugation in the polymer backbone, resulting in a chain composed of many chromophore units, whose relative energies depend on the segment lengths. Photoexcitation of the polyfluorene by a femtosecond laser pulse results in the excitation of polyfluorene, which then undergoes direct energy transfer to the pendant Ru(II) complexes, producing Ru(II)* excited states within 500 fs after photoexcitation. Femtosecond transient absorption data show the presence of electron transfer from PF* to Ru(II) to form charge-separated (CS) products within 1-2 ps. The decay of the oxidized and reduced products, PF(+•) and Ru(I), through back electron transfer are followed using picosecond transient absorption methods.
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Affiliation(s)
- Li Wang
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Egle Puodziukynaite
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Ryan P Vary
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Erik M Grumstrup
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ryan M Walczak
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Olga Y Zolotarskaya
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Kirk S Schanze
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - John R Reynolds
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
- §School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - John M Papanikolas
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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