Dimerization of titanyl phthalocyanine in thin films prepared by surface polymerization by ion-assisted deposition

Zachary, Adam M.; Drábik, M.; Choi, Yong‐Kook; Bolotin, Igor L.; Biederman, Hynek; Hanley, Luke

doi:10.1116/1.2835091

Cited by 7 publications

(17 citation statements)

References 45 publications

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“…This is not surprising considering that TiOPc in its "bulk" form adopts a double layer structure. 31,32 Furthermore, the absence of a clear shakeup structure for the peak at higher binding energy is in line with a charge reduction in the HOMO. This is also supported by the disappearance of the HOMO feature in valence band spectra from 1 ML TiOPc (Figure 5b).…”

Section: Resultsmentioning

confidence: 69%

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO₂ Interfaces

Ahmadi

Palmgren

et al. 2009

J. Phys. Chem. C

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Adsorption of titanyl phthalocyanine (TiOPc) on rutile TiO 2 (110) modified by a set of pyridine derivatives (2,2′-bipyridine, 4,4′-bipyridine, and 4-tert-butyl pyridine) has been investigated using synchrotron radiation based X-ray photoelectron spectroscopy (XPS). For the unmodified TiOPc/TiO 2 system, a strong charge transfer is observed from the first layer TiOPc into the substrate, which leads to a molecular layer at the interface with a depleted highest occupied molecular orbital (HOMO). However, precovering the TiO 2 surface with a saturated pyridine monolayer effectively reduce this process and leave the TiOPc in a less perturbed molecular state. Furthermore, the TiOPc HOMO and core levels are observed at different binding energies ranging by 0.3 eV on the three pyridine monolayers, which is ascribed to differences in surface potentials set up by the different pyridine/TiO 2 systems.

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Section: Resultsmentioning

confidence: 69%

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO₂ Interfaces

Ahmadi

Palmgren

et al. 2009

J. Phys. Chem. C

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“…Ion modification also increased the carbon content in the films and dissociated functional units of the 4T oligomers. The 50 eV ion beam consisted of ∼97% molecular ions denoted as C 2 H x + ( x = 0–2), ∼3% CH x + ( x = 0, 1), and an indeterminate amount of H x + ions, so the ion beam was modeled by C 2 H + ions. The simulations predicted that bond breakage in 3T oligomers as a result of the deposition of the ions is a critical step toward producing oligomer–PbS bonds.…”

Section: Discussionmentioning

confidence: 99%

Acetylene Ion Enhanced Bonding of PbS Nanoparticles to Quaterthiophene in Thin Films

et al. 2012

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Lead sulfide (PbS) nanoparticles of ∼3–5 nm average diameter were codeposited into quaterthiophene (4T) organic films, which in some cases, were additionally modified by simultaneous 50 eV acetylene ion bombardment. The film composition and PbS–4T bonding were monitored by X-ray photoelectron spectroscopy (XPS) and laser desorption postionization mass spectrometry (LDPI-MS). S2p core-level XP spectra indicated that ion-modified films displayed enhanced bonding between 4T and PbS nanoparticles. LDPI mass spectra found thiophene fragments bound to PbS in ion-modified films. Computational simulations were used to investigate the mechanisms by which the incident particles chemically modified the thiophene–PbS nanoparticle interactions: molecular dynamics, density functional theory simulations were carried out on α-terthiophene (3T) analogues of 4T films interacting with (PbS)16 clusters. The simulations showed that, in the absence of acetylene ion modification, a weak charge transfer from the PbS cluster to the nearest 3T molecule occurred, suggestive of little interaction between intact organic matrix molecules and PbS nanoparticles. However, the simulations predicted the formation of a covalent bond between PbS and the oligothiophene film as a result of acetylene ion modification, in support of the experimental observations. These results help explain the recent observation of enhanced photoconductivity in these films upon ion modification ( Majeski M. W. Majeski M. W. J. Vac. Sci. Technol. A20123004D109).

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“…Acetylene ions with 50 eV kinetic energy were generated by a Kaufman ion source (IBS 250, 3 cm, Veeco/Commonwealth Scientific, Plainview, NY) 15 and used to modify the films simultaneous with 4T and PbS cluster deposition. The ion source was mounted 45 from the surface normal.…”

Section: Experiments a Sample Preparationmentioning

confidence: 99%

“…10 The acetylene ions used in ion-assisted deposition behave both as catalysts and reagents by energetically inducing bonding between condensed phase species and forming adducts with the neutral reagents. [11][12][13][14][15] X-ray photoelectron spectroscopy (XPS) was employed to probe photoconductivity of the PbS nanoparticle-4T composite films. For insulating and semiconducting samples, it has been observed that surface charging can shift the measured binding energies in an X-ray photoelectron (XP) spectrum.…”

Section: Introductionmentioning

confidence: 99%

Photoresponse of PbS nanoparticles–quaterthiophene films prepared by gaseous deposition as probed by XPS

Majeski

Pleticha

Bolotin

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Semiconducting lead sulfide (PbS) nanoparticles were cluster beam deposited into evaporated quaterthiophene (4T) organic films, which in some cases were additionally modified by simultaneous 50 eV acetylene ion bombardment. Surface chemistry of these nanocomposite films was first examined using standard x-ray photoelectron spectroscopy (XPS). XPS was also used to probe photoinduced shifts in peak binding energies upon illumination with a continuous wave green laser and the magnitudes of these peak shifts were interpreted as changes in relative photoconductivity. The four types of films examined all displayed photoconductivity: 4T only, 4T with acetylene ions, 4T with PbS nanoparticles, and 4T with both PbS nanoparticles and acetylene ions. Furthermore, the ion-modified films displayed higher photoconductivity, which was consistent with enhanced bonding within the 4T organic matrix and between 4T and PbS nanoparticles. PbS nanoparticles displayed higher photoconductivity than the 4T component, regardless of ion modification.

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Dimerization of titanyl phthalocyanine in thin films prepared by surface polymerization by ion-assisted deposition

Cited by 7 publications

References 45 publications

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO₂ Interfaces

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO₂ Interfaces

Acetylene Ion Enhanced Bonding of PbS Nanoparticles to Quaterthiophene in Thin Films

Photoresponse of PbS nanoparticles–quaterthiophene films prepared by gaseous deposition as probed by XPS

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Dimerization of titanyl phthalocyanine in thin films prepared by surface polymerization by ion-assisted deposition

Cited by 7 publications

References 45 publications

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO2 Interfaces

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO2 Interfaces

Acetylene Ion Enhanced Bonding of PbS Nanoparticles to Quaterthiophene in Thin Films

Photoresponse of PbS nanoparticles–quaterthiophene films prepared by gaseous deposition as probed by XPS

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Modification of Charge Transfer and Energy Level Alignment at Organic/TiO₂ Interfaces

Modification of Charge Transfer and Energy Level Alignment at Organic/TiO₂ Interfaces