Tuning Energy Level Alignment At Organic/Semiconductor Interfaces Using a Built-In Dipole in Chromophore–Bridge–Anchor Compounds

Rangan, Sylvie; Batarseh, Alberto; Chitre, Keyur; Kopecky, Andrew; Galoppini, Elena; Bartynski, Robert

doi:10.1021/jp502917c

Cited by 15 publications

(48 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…22 Furthermore, the direction and magnitude of the shift was consistent with that predicted by a simple parallel-plate capacitor model. 22 The magnitude of the shift, i.e. (±) ∼100 meV, was small.…”

Section: Introductionsupporting

confidence: 74%

“…In a proof-of concept experiment we recently reported the UV photoemission spectroscopy (UPS) study of 1a, 2a and 3a bound to a ZnO (11−20) single crystal surface to probe the dipole effect on the alignment of the frontier orbital energies with respect to the band edges of the semiconductor. 22 It was determined that the interfacial dipole layer that is formed upon binding to ZnO (11−20) single crystal establishes a potential difference that shifts the HOMO and LUMO levels of the dye with respect to those of the semiconductor. 22 Furthermore, the direction and magnitude of the shift was consistent with that predicted by a simple parallel-plate capacitor model.…”

Section: Introductionmentioning

confidence: 99%

“…22 It was determined that the interfacial dipole layer that is formed upon binding to ZnO (11−20) single crystal establishes a potential difference that shifts the HOMO and LUMO levels of the dye with respect to those of the semiconductor. 22 Furthermore, the direction and magnitude of the shift was consistent with that predicted by a simple parallel-plate capacitor model. 22 The magnitude of the shift, i.e.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photoelectrochemical properties of porphyrin dyes with a molecular dipole in the linker

et al. 2015

Self Cite

View full text Add to dashboard Cite

The electronic properties of three porphyrin-bridge-anchor photosensitizers are reported with (1a, 1e, 3a and 3e) or without (2a and 2e) an intramolecular dipole in the bridge. The presence and orientation of the bridge dipole is hypothesized to influence the photovoltaic properties due to variations in the intrinsic dipole at the semiconductor-molecule interface. Electrochemical studies of the porphyrin-bridge-anchor dyes self-assembled on mesoporous nanoparticle ZrO2 films, show that the presence or direction of the bridge dipole does not have an observable effect on the electronic properties of the porphyrin ring. Subsequent photovoltaic measurements of nanostructured TiO2 semiconductor films in dye sensitized solar cells show a reduced photocurrent for photosensitizers 1a and 3a containing a bridge dipole. However, cooperative increased binding of the 1a + 3a co-sensitized device demonstrates that dye packing overrides any differences due to the presence of the small internal dipole.

show abstract

Section: Introductionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Photoelectrochemical properties of porphyrin dyes with a molecular dipole in the linker

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Data were collected at 100 K with the crystal in a stream of N 2 gas on a Bruker APEX2 diffractometer with CCD detector using Cu Kα radiation (λ = 1.54178 Å); cell refinement was done by APEX2. 45 Numerical absorption corrections from face indices 27 The shift direction is indicated by a red arrow.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Zinc Tetraphenylporphyrin Rigid Rods with a Built-In Dipole

et al. 2015

Self Cite

View full text Add to dashboard Cite

Three Zn(II) tetraphenylporphyrins (ZnTPP) were synthesized to study the influence of a molecular dipole on the energy level alignment of a chromophore bound to a metal oxide semiconductor: ZnTPP-PE(DA)-IpaOMe (1), ZnTPP-PE-IpaOMe (2), and ZnTPP-PE(AD)-IpaOMe (3). Each contained a rigid-rod linker made of a p-phenylene ethynylene (PE) moiety terminated with the methyl ester of an isophthalic acid unit (Ipa). Porphyrins 1 and 3 contained an intramolecular dipole in the central phenyl ring, which was built by introducing electron donor (D, NMe2) and acceptor (A, NO2) substituents in para position to each other. In 1 and 3, the relative position of the D and A substituents, and therefore the dipole direction, was reversed. Porphyrin 2, without substituents in the linker, was synthesized for a comparison. The structures of precursors to 1 and 3 and the structure of 1 were determined by single crystal X-ray analysis. Solution UV-vis and steady-state fluorescence spectra of 1-3 were identical to each other and exhibited the spectral features typical of the ZnTPP chromophore and their electrochemical properties were also very similar. Methyl esters 1-3 were hydrolyzed to the corresponding carboxylic acids for binding to metal oxide semiconductors.

show abstract

“…Energy level alignment deduced from electrochemical measurements in solvent environment was different for theses measurements when compared to level alignment measured by the Bartynski group via UPS in UHV. 11 …”

Section: Resultsmentioning

confidence: 99%

Heterogeneous Electron-Transfer Dynamics through Dipole-Bridge Groups

Nieto-Pescador

Abraham

et al. 2015

J. Phys. Chem. C

Self Cite

View full text Add to dashboard Cite

Heterogeneous electron transfer (HET) between photoexcited molecules and colloidal TiO2 has been investigated for a set of Zn-porphyrin chromophores attached to the semiconductor via linkers that allow to change level alignment by 200 meV by reorientation of the dipole moment. These unique dye molecules have been studied by femtosecond transient absorption spectroscopy in solution and adsorbed on the TiO2 colloidal film in vacuum. In solution energy transfer from the excited chromophore to the dipole group has been identified as a slow relaxation pathway competing with S2-S1 internal conversion. On the film heterogeneous electron transfer occurred in 80 fs, much faster compared to all intramolecular pathways. Despite a difference of 200 meV in level alignment of the excited state with respect to the semiconductor conduction band, identical electron transfer times were measured for different linkers. The measurements are compared to a quantum-mechanical model that accounts for electronic-vibronic coupling and finite band width for the acceptor states. We conclude that HET occurs into a distribution of transition states that differs from regular surface states or bridge mediated states.

show abstract

Tuning Energy Level Alignment At Organic/Semiconductor Interfaces Using a Built-In Dipole in Chromophore–Bridge–Anchor Compounds

Cited by 15 publications

References 43 publications

Photoelectrochemical properties of porphyrin dyes with a molecular dipole in the linker

Photoelectrochemical properties of porphyrin dyes with a molecular dipole in the linker

Synthesis of Zinc Tetraphenylporphyrin Rigid Rods with a Built-In Dipole

Heterogeneous Electron-Transfer Dynamics through Dipole-Bridge Groups

Contact Info

Product

Resources

About