Femtosecond two-photon photoemission probing electron injection from the excited singlet state of perylene attached to a long rigid tripod anchor-cum-spacer on rutile TiO2(110)

Gundlach, Lars; Felber, Silke; Storck, W.; Galoppini, Elena; Wei, Qinhua; Willig, F.

doi:10.1163/1568567053146841

Cited by 26 publications

(36 citation statements)

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“…Such photodynamic studies provide detailed information into the thermalization of 'hot' electrons in the TiO 2 CB. For example, Gundlach and coworkers used 2PPE to track electron injection thermalization from two dyes adsorbed on R TiO 2 (110) [390,391]. Fast initial decay of the 2PPE signal resulting from thermalization of the injected electron occurred on the 10 fs timescale.…”

Section: Charge Separation and Thermalizationmentioning

confidence: 99%

“…The dynamics of electron injection from an electronically excited dye molecule into the CB of TiO 2 has become an intensely studied phenomenon in the field of heterogeneous photochemistry [71,163,164,198,390,391,447,448,494,497,511,532,535,536,601,. The underlying utility of TiO 2 (or other similar semiconductors) in dye sensitization is its ability to accept into its CB excited electrons with high efficiency and transport these electrons away from the sensitizer.…”

Section: Excited Electron Donor To Tio 2 Conduction Bandmentioning

confidence: 99%

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A surface science perspective on TiO2 photocatalysis

Henderson

2011

Surface Science Reports

1,855

1,634

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a b s t r a c tThe field of surface science provides a unique approach to understanding bulk, surface and interfacial phenomena occurring during TiO 2 photocatalysis. This review highlights, from a surface science perspective, recent literature that provides molecular-level insights into photon-initiated events occurring at TiO 2 surfaces. Seven key scientific issues are identified in the organization of this review. These are: (1) photon absorption, (2) charge transport and trapping, (3) electron transfer dynamics, (4) the adsorbed state, (5) mechanisms, (6) poisons and promoters, and (7) phase and form. This review ends with a brief examination of several chemical processes (such as water splitting) in which TiO 2 photocatalysis has made significant contributions in the literature.

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Section: Charge Separation and Thermalizationmentioning

confidence: 99%

Section: Excited Electron Donor To Tio 2 Conduction Bandmentioning

confidence: 99%

A surface science perspective on TiO2 photocatalysis

Henderson

2011

Surface Science Reports

1,855

1,634

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“…14 Rigid ring structures consisting of saturated -C-C-bonds like cyclooctane 10 and adamantane 10,15 can be used as electronic tunneling barriers to slow down HET. Similar ring structures have been used earlier to slow down electron transfer in donor-bridge-acceptor molecules.…”

Section: Introductionmentioning

confidence: 99%

Test of theoretical models for ultrafast heterogeneous electron transfer with femtosecond two-photon photoemission data

2009

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Abstract. The energy distribution of electrons injected into acceptor states on the surface of TiO 2 was measured with femtosecond two-photon photoemission. Shape and relative energetic position of these distribution curves with respect to the corresponding donor states, i.e. of perylene chromophores in the first excited singlet state attached via different bridge-anchor groups to the TiO 2 surface, were compared with the predictions of different theoretical models for light-induced ultrafast heterogeneous electron transfer (HET). Gerischer's early scenario for light-induced HET was considered and two recent explicit calculations, i.e. a fully quantum mechanical analytical model and a time-dependent density functional theory model based on molecular dynamics simulations for the vibrational modes were also considered. Based on the known vibrational structure in the photoionization spectrum of perylene in the gas phase and that measured in the linear absorption spectra of the perylene chromophores anchored on the TiO 2 surface the energy distribution curves for the injected electrons were fitted assuming the excitation of the dominant 0⋅17 eV vibrational mode in the ionized perylene chromophore leading to a corresponding Franck-Condon dictated progression in the energy distribution curves. Each individual peak was fitted with a Voigt profile where the Lorentzian contribution was taken from the time-resolved HET data and the Gaussian contribution attributed to inhomogeneous broadening. The measured room temperature energy distribution curves for the injected electrons are explained with the fully quantum mechanical model for light-induced HET with the high energy, 0⋅17 eV, skeletal stretching mode excited in the ionized perylene chromophore. The corresponding energy distribution of the injected electrons is fully accommodated in acceptor states on the TiO 2 surface fulfilling the wide band limit.

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“…It is well suited for a systematic study of photoinduced ultrafast HET since the first excited electronic state of perylene is energetically positioned about 1 eV above the conduction band edge of TiO 2 thus realizing a mid-band charge injection situation. Introducing different bridge-anchor groups the transfer coupling which initiates HET can be tuned from a strongcoupling situation (with charge injection times of 10 fs) down to weaker coupling strengths (with charge injection times of up to 1 ps [23]). …”

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confidence: 99%