Electron transfer dynamics of triphenylamine dyes bound to TiO2 nanoparticles from femtosecond stimulated Raman spectroscopy

Handle URI:
http://hdl.handle.net/10754/562720
Title:
Electron transfer dynamics of triphenylamine dyes bound to TiO2 nanoparticles from femtosecond stimulated Raman spectroscopy
Authors:
Hoffman, David P.; Lee, Olivia P.; Millstone, Jill E.; Chen, Mark S.; Su, Timothy A.; Creelman, Mark; Frechet, Jean ( 0000-0001-6419-0163 ) ; Mathies, Richard A.
Abstract:
Interfacial electron transfer between sensitizers and semiconducting nanoparticles is a crucial yet poorly understood process. To address this problem, we have used transient absorption (TA) and femtosecond stimulated Raman spectroscopy (FSRS) to investigate the photoexcited dynamics of a series of triphenylamine-coumarin dye/TiO2 conjugates. The TA decay is multiexponential, spanning time scales from 100 fs to 100 ps, while the characteristic transient Raman spectrum of the radical cation decays biexponentially with a dominant ∼3 ps component. To explain these observations, we propose a model in which the decay of the TA is due to hot electrons migrating from surface trap states to the conduction band of TiO 2 while the decay of the Raman signature is due to internal conversion of the dye molecule. Furthermore, the S1 Raman spectrum of TPAC3, a dye wherein a vinyl group separates the triphenylamine and coumarin moieties, is similar to the S1 Raman spectrum of trans-stilbene; we conclude that their S1 potential energy surfaces and reactivity are also similar. This correlation suggests that dyes containing vinyl linkers undergo photoisomerization that competes with electron injection. © 2013 American Chemical Society.
KAUST Department:
Chemical Science Program; Physical Sciences and Engineering (PSE) Division
Publisher:
American Chemical Society
Journal:
Journal of Physical Chemistry C
Issue Date:
11-Apr-2013
DOI:
10.1021/jp400369b
Type:
Article
ISSN:
19327447
Sponsors:
This work was supported the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract DE-ACO2-05CH11231 and in part by the Mathies Royalty fund. DFT calculations were carried out with the support of the National Science Foundation Grant CHE-0840505, and M.S.C. thanks the Camille and Henry Dreyfus Postdoctoral Program in Environmental Chemistry for a fellowship.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program

Full metadata record

DC FieldValue Language
dc.contributor.authorHoffman, David P.en
dc.contributor.authorLee, Olivia P.en
dc.contributor.authorMillstone, Jill E.en
dc.contributor.authorChen, Mark S.en
dc.contributor.authorSu, Timothy A.en
dc.contributor.authorCreelman, Marken
dc.contributor.authorFrechet, Jeanen
dc.contributor.authorMathies, Richard A.en
dc.date.accessioned2015-08-03T11:03:05Zen
dc.date.available2015-08-03T11:03:05Zen
dc.date.issued2013-04-11en
dc.identifier.issn19327447en
dc.identifier.doi10.1021/jp400369ben
dc.identifier.urihttp://hdl.handle.net/10754/562720en
dc.description.abstractInterfacial electron transfer between sensitizers and semiconducting nanoparticles is a crucial yet poorly understood process. To address this problem, we have used transient absorption (TA) and femtosecond stimulated Raman spectroscopy (FSRS) to investigate the photoexcited dynamics of a series of triphenylamine-coumarin dye/TiO2 conjugates. The TA decay is multiexponential, spanning time scales from 100 fs to 100 ps, while the characteristic transient Raman spectrum of the radical cation decays biexponentially with a dominant ∼3 ps component. To explain these observations, we propose a model in which the decay of the TA is due to hot electrons migrating from surface trap states to the conduction band of TiO 2 while the decay of the Raman signature is due to internal conversion of the dye molecule. Furthermore, the S1 Raman spectrum of TPAC3, a dye wherein a vinyl group separates the triphenylamine and coumarin moieties, is similar to the S1 Raman spectrum of trans-stilbene; we conclude that their S1 potential energy surfaces and reactivity are also similar. This correlation suggests that dyes containing vinyl linkers undergo photoisomerization that competes with electron injection. © 2013 American Chemical Society.en
dc.description.sponsorshipThis work was supported the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract DE-ACO2-05CH11231 and in part by the Mathies Royalty fund. DFT calculations were carried out with the support of the National Science Foundation Grant CHE-0840505, and M.S.C. thanks the Camille and Henry Dreyfus Postdoctoral Program in Environmental Chemistry for a fellowship.en
dc.publisherAmerican Chemical Societyen
dc.titleElectron transfer dynamics of triphenylamine dyes bound to TiO2 nanoparticles from femtosecond stimulated Raman spectroscopyen
dc.typeArticleen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalJournal of Physical Chemistry Cen
dc.contributor.institutionDepartment of Chemistry, University of California Berkeley, Berkeley, CA 94720, United Statesen
dc.contributor.institutionMaterials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United Statesen
dc.contributor.institutionDepartment of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United Statesen
dc.contributor.institutionDepartment of Chemistry, Columbia University, New York, NY 10027, United Statesen
kaust.authorFrechet, Jeanen
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