Oriented Crystalline Films of Tris(8-hydroxyquinoline) Aluminum(III): Growth of the Alpha Polymorph onto an Ultra-Oriented Poly(tetrafluoroethylene) Substrate

Moulin, Jean‐François; Brinkmann, Martin; Thierry, A.; Wittmann, J. C.

doi:10.1002/1521-4095(20020318)14:6<436::aid-adma436>3.0.co;2-k

Cited by 48 publications

(50 citation statements)

References 23 publications

(17 reference statements)

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“…A texture with needles lying in the plane of the substrate, similar to that formed onto ultraoriented poly͑tet-rafluoroethylene͒ substrates appears. 26 This crystallization process did not occur when the films were quenched under primary vacuum immediately after deposition. For the study of the rate dependence of the nucleation density N, the substrate temperature was rapidly quenched to room temperature ͑10°C/min͒ by using a nitrogen cooling system in order to avoid coarsening phenomena.…”

Section: Methodsmentioning

confidence: 99%

Mechanism of nonrandom pattern formation of polar-conjugated molecules in a partial wetting regime

Brinkmann

Graff

Biscarini³

2002

Phys. Rev. B

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An original nucleation and growth process has been investigated for vacuum-deposited films of a polarconjugated molecule, tris-͑8-hydroxyquinoline͒ aluminum ͑III͒ (Alq 3 ), onto the apolar H-terminated Si͑100͒. Homogeneous nucleation of amorphous Alq 3 clusters is restricted to the early stage of deposition and is characterized by a large critical nucleus size iϭ5, as determined from the dependence of the density of stable nuclei N on deposition rate . Alq 3 clusters grow in a partial wetting regime to form correlated droplet patterns. For moderate deposition rates around 1 nm/min, patterns exhibit both ͑i͒ a typical scale invariance of the droplet size distribution with coverage and substrate temperature and ͑ii͒ strong correlations between the size and position of the droplets. Both these characteristics result from the absence of coarsening-e.g., Ostwald ripening, secondary nucleation, and coalescence during growth. Spatial correlations are analyzed by using Voronoi tesselation, which demonstrates the validity of a phenomenological capture zone model for correlated growth. Correlations emerge in the early stage of growth via direct ripening and further develop during growth by diffusive interactions between domains. Direct ripening manifests itself by the introduction of a minimum cutoff distance between droplets, which causes a significant narrowing of the droplet size distribution. During growth, diffusive interactions between droplets cause their centers of mass to move towards empty depleated areas, which results in enhanced spatial correlations. This peculiar nucleation and growth mechanism allows one to obtain droplet patterns where the interdroplet distance and droplet size can be tuned independently via deposition temperature and time.

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Section: Methodsmentioning

confidence: 99%

Mechanism of nonrandom pattern formation of polar-conjugated molecules in a partial wetting regime

Brinkmann

Graff

Biscarini³

2002

Phys. Rev. B

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“…[153] The growth of thin films of the a polymorph of tris(8-hydroxyquinoline) aluminum(III) on PTFE substrates, also by PVD, has been recently reported. [154] In the case of relatively large planar molecules, as for CuPc and PTCDA, molecules tend to lie parallel to the substrates for high deposition rates. [155] This ordering, although preserving the crystallographic phase, may not be desired for applications such as OTFTs (see Sec.…”

Section: Polymorphismmentioning

confidence: 99%

Perspectives on Thin Molecular Organic Films

Fraxedas¹

2002

Adv. Mater.

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The engineering versatility of molecular organic materials, together with their attractive electronic, magnetic, and optical properties, have triggered their preparation as thin films in the last years. Although the interactions between molecules and inorganic substrates are rather weak (van der Waals, hydrogen bonding, etc.), the crystallographic phase, the type and degree of orientation, and the morphology of the resulting films critically depend on the interface and the kinetics of growth. The control of the structure and morphology of the films is thus essential when envisioning practical applications. The relevance of interfaces in the growth and doping of films is discussed, and the phenomenology of polymorphism is explored. Additional issues such as the mechanical properties are also addressed. The figure, showing a scanning tunneling microscopy image of a monolayer of bis(ethylenedithio)‐tetrathiafulvalene on a Au(111) substrate, illustrates the interface issue.

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“…Among the various Schiff bases, the coordination compounds of 8-hydroxyquinoline are well known due to their applications particularly in OLED (organic light emitting diode) materials [23,24]. But the study on catalytic behavior of such species is rather limited.…”

Section: Introductionmentioning

confidence: 99%

Ruthenium(II) 8-quinolinolates: Synthesis, characterization, crystal structure and catalysis in the synthesis of 2-oxazolines

Anitha

Manikandan

Prakash

et al. 2015

Journal of Organometallic Chemistry

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New octahedral ruthenium(II) complexes (1-4) have been synthesized from the reaction of ruthenium(II) precursors [RuHCl(CO)(EPh 3 ) 3 ] (E = P or As) with the bidentate Schiff base ligands, 2-((2,6-dimethylphenylimino)methyl)quinolin-8-ol (L 1 ) and 2-((2,6-diisopropylphenylimino)methyl)quinolin-8-ol (L 2 ) in ethanol. These complexes have been characterized by elemental analyses, IR, UV-Vis, 1 H, 13 C and 31 P NMR and ESI-Mass spectroscopy. The molecular structure of the complex [RuCl(CO)(PPh 3 ) 2 (L 2 )] (2) was determined by single-crystal X-ray diffraction, which reveals a distorted octahedral geometry around ruthenium(II) ion. The catalytic activity of the new complexes was evaluated for the condensation of nitriles with ethanolamine under solvent free conditions. The processes were operative with aromatic and heteroaromatic nitriles and tolerated several substitutional groups.The studies on the effect of substitution over ligands, coligands, reaction time, temperature and catalyst loading were carried out in order to find the best catalyst in this series of complexes and favorable reaction conditions. A probable mechanism for the catalytic condensation of nitrile has also been proposed. The catalyst was recovered and recycled up to five times without significant loss of its activity.

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Oriented Crystalline Films of Tris(8-hydroxyquinoline) Aluminum(III): Growth of the Alpha Polymorph onto an Ultra-Oriented Poly(tetrafluoroethylene) Substrate

Cited by 48 publications

References 23 publications

Mechanism of nonrandom pattern formation of polar-conjugated molecules in a partial wetting regime

Mechanism of nonrandom pattern formation of polar-conjugated molecules in a partial wetting regime

Perspectives on Thin Molecular Organic Films

Ruthenium(II) 8-quinolinolates: Synthesis, characterization, crystal structure and catalysis in the synthesis of 2-oxazolines

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