Thickness-dependent electronic properties and molecular orientation of diradical metal complex thin films grown on SiO2

Hosokai, Takuya; Mitsuo, N.; Noro, Shin Ichiro; Nakamura, Takayoshi; Kera, Satoshi; Sakamoto, Kazuyuki; Ueno, Nobuo

doi:10.1016/j.cplett.2010.01.020

Cited by 5 publications

(4 citation statements)

References 23 publications

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“…A sharp feature (∗) in Figures a and b may be attributed to the high density-of-states of conduction bands of the picene thin films, as the same analogue to that reported for acene thin films with up-right standing orientation and high crystallinity . Very broad features in the substrate spectra of UPS and MAES are ascribed to the nonbonding states of the O 2p orbitals of SiO 2 surface (O 2p) and the σ(Si–O–Si) bonding state . With increasing d , the intensity of the substrate features decreases gradually but still remains visible even at 8.0 nm, which is much larger than the detection depth of UPS and MAES.…”

Section: Results and Discussionsupporting

confidence: 66%

“…23 Very broad features in the substrate spectra of UPS and MAES are ascribed to the nonbonding states of the O 2p orbitals of SiO 2 surface (O 2p) and the σ(Si−O−Si) bonding state. 55 With increasing d, the intensity of the substrate features decreases gradually but still remains visible even at 8.0 nm, which is much larger than the detection depth of UPS and MAES. UPS can detect inelastic photoelectrons coming from the outmost surface to a depth of ∼1 nm, while MAES detects only electrons from the outermost surface.…”

Section: ■ Results and Discussionmentioning

confidence: 90%

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Thickness and Substrate Dependent Thin Film Growth of Picene and Impact on the Electronic Structure

et al. 2015

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Thickness and substrate dependence of film growth, morphology, unit-cell structure, and electronic structures was thoroughly investigated for picene, the zigzag connected 5-ring molecule, by employing complementary techniques of in situ real-time X-ray reflectivity/diffraction, in situ electron spectroscopies, and atomic force microscopy. A different kind of thickness dependent structural transition was observed on SiO2 and graphite, resulting in a distinct electronic structure. On SiO2 picene films with 3D crystalline domains are formed with nearly upright molecular orientation from the initial growth stage. With increasing the film thickness the in-plane dimensions of the unit cell in the initially grown domains become smaller (in other words, more compressed), and, at the same time, crystalline domains with a more relaxed structure are nucleating on top of the compressed domains. In spite of such structural changes, the electronic structure, namely energy position of the highest occupied molecular orbital and threshold ionization potential (IPT), is not significantly altered. On graphite, on the other hand, we found a transition from a 2D (layer) to a 3D (island) growth mode with a variation of the molecular orientation from flat-lying to tilted one. The IPT changes significantly between the 2D and 3D growth regime in contrast to the SiO2 system. The origin of the different IPTs of these picene thin films is discussed. The present results are compared with other planar π-conjugated compounds, in particular pentacene which is a structural isomer of picene and shows electronic properties strongly different from picene thin films.

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Section: Results and Discussionsupporting

confidence: 66%

Section: ■ Results and Discussionmentioning

confidence: 90%

Thickness and Substrate Dependent Thin Film Growth of Picene and Impact on the Electronic Structure

et al. 2015

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“…In these multilayered organic-based devices a suitable tailoring of properties like high photocurrent quantum efficiencies can be achieved using different combinations of electron-donor and electron-acceptor layers. [1][2][3][4][5] For such donor-acceptor heterojunctions some of the considered constituting materials are C60, whose mechanical, electrical and chemical properties are favorable for the fabrication of reliable devices, 6 and pentacene (P5) which shows a high mobility of holes 7 and distinct polymorph phases. 8 It is also well-known that in organic electronics the role of the interface is crucial since key processes such as charge transfer or charge recombination occur in its vicinity.…”

Section: Introductionmentioning

confidence: 99%

The role of charge transfer in the energy level alignment at the pentacene/C60 interface

Beltrán

Ortega

2014

Phys. Chem. Chem. Phys.

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Understanding the mechanism of energy level alignment at organic-organic interfaces is a crucial line of research to optimize applications in organic electronics. We address this problem for the C60-pentacene interface by performing local-orbital Density Functional Theory (DFT) calculations, including the effect of the charging energies on the energy gap of both organic materials. The results are analyzed within the induced density of interface states (IDIS) model. We find that the induced interface potential is in the range of 0.06-0.10 eV, in good agreement with the experimental evidence, and that such potential is mainly induced by the small, but non-negligible, charge transfer between the two compounds and the multipolar contribution associated with pentacene. We also suggest that an appropriate external intercompound potential could create an insulator-metal transition at the interface.

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“…[1][2][3][4][5][6] One of the most promising strategies is based on the concept of hybrid molecular materials, resulting in the preparation of thin films of nickel(II) [4][5][6][7][8] and cobalt(II) [9][10][11] complexes which have the ability to solve several problems in various areas such as solar energy, information storage, catalysis, pollution sensor. [7][8][9][10] The elaboration of metallic-complexes thin layers has been studied using various deposition techniques, such as atomic layer deposition (ALD), [12] molecular self-assembly (MSA), [13] radio frequency co-sputtering (RFC), [14] Langmuir-Blodgett technique (LB), [15] spin-coating, [16] chemical bath deposition (CBD), [17][18][19] chemical vapor deposition (CVD), [20] sol-gel process, [21] and (successive ionic layer adsorption and reaction (SILAR). [9,10,22] However, the CBD technique is a simplified and not expensive method used for the synthesis of [Ni(8-HQ) 2 (H 2 O) 2 ] and [Co(8-HQ) 2 (H 2 O) 2 ] with a very good homogeneity.…”

Section: Introductionmentioning

confidence: 99%

Structural and optical proprieties of [M(8-HQ) ₂ (H ₂ O) ₂ ] {M = Ni(II), Co(II)} thin films deposed by chemical bath deposition method

Mamine

Bendjeffal

Djebli

et al. 2020

Inorganic and Nano-Metal Chemistry

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The objective of this study was the deposition of thin films of 8-hydroxyquinolin (8-HQ) Cobalt(II) and Nickel(II) complexes onto glass substrates using the chemical bath deposition (CBD) method. The deposition experiments were carried out under the effect of some physicochemical factors such as solution temperature (25 C-55 C), medium pH (1-6), metal: ligand molar stoichiometric ratio (1:1-1:3), and immersion time (in the range 10-60 min). The obtained thin films were characterized using many analytical methods (UV-Vis spectrophotometry, infrared spectrophotometry, optical microscopy, scanning electron microscopy, and X-ray diffraction). The study of the optical properties of the obtained thin films showed that the complexes 2 (H 2 O) 2 ] and [Co(8-HQ) 2 (H 2 O) 2 ] have strong absorbance in UV area corresponding to a p-p Ã or n-p Ã electronic transition between the HOMO and the LUMO with a gap's energy in the range 4.1 and 4.4 eV. In the light of the optical measurements, [Ni(8-HQ) 2 (H 2 O) 2 ] and [Co(8-HQ) 2 (H 2 O) 2 ] complexes can be considered as semiconductors.

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Thickness-dependent electronic properties and molecular orientation of diradical metal complex thin films grown on SiO2

Cited by 5 publications

References 23 publications

Thickness and Substrate Dependent Thin Film Growth of Picene and Impact on the Electronic Structure

Thickness and Substrate Dependent Thin Film Growth of Picene and Impact on the Electronic Structure

The role of charge transfer in the energy level alignment at the pentacene/C60 interface

Structural and optical proprieties of [M(8-HQ) ₂ (H ₂ O) ₂ ] {M = Ni(II), Co(II)} thin films deposed by chemical bath deposition method

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Thickness-dependent electronic properties and molecular orientation of diradical metal complex thin films grown on SiO2

Cited by 5 publications

References 23 publications

Thickness and Substrate Dependent Thin Film Growth of Picene and Impact on the Electronic Structure

Thickness and Substrate Dependent Thin Film Growth of Picene and Impact on the Electronic Structure

The role of charge transfer in the energy level alignment at the pentacene/C60 interface

Structural and optical proprieties of [M(8-HQ) 2 (H 2 O) 2 ] {M = Ni(II), Co(II)} thin films deposed by chemical bath deposition method

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Product

Resources

About

Structural and optical proprieties of [M(8-HQ) ₂ (H ₂ O) ₂ ] {M = Ni(II), Co(II)} thin films deposed by chemical bath deposition method