Self-Assembly in Ultrahigh Vacuum:  Growth of Organic Thin Films with a Stable <i>In-Plane</i> Directional Order

Cai, Chengzhi; Bösch, Martin; Tao, Ye; Müller, Bert; Gan, Zhehong; Kündig, Armin; Bosshard, Christian; Liakatas, Ilias; Jäger, and Matthias; Günter, Peter

doi:10.1021/ja981551g

Cited by 45 publications

(39 citation statements)

References 9 publications

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“…Specifically, we employed the two molecular building blocks 4-[trans-2-(pyrid-4-yl-vinyl)]benzoic acid (PVBA) and 4-[(pyrid-4-yl-ethynyl)]-benzoic acid (PEBA) designed for nonlinear optics applications. [25][26][27][28] The structure formulas given in Figure 1 show that the two molecules are similar. Both species are rigid and planar.…”

Section: Introductionmentioning

confidence: 97%

Stereochemical Effects in Supramolecular Self-Assembly at Surfaces: 1-D versus 2-D Enantiomorphic Ordering for PVBA and PEBA on Ag(111)

et al. 2002

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Abstract:We present investigations on noncovalent bonding and supramolecular self-assembly of two related molecular building blocks at a noble metal surface: 4-[trans-2-(pyrid-4-yl-vinyl)]benzoic acid (PVBA) and 4-[(pyrid-4-yl-ethynyl)]benzoic acid (PEBA). These rigid, rodlike molecules comprising the same complementary moieties for hydrogen bond formation are comparable in shape and size. For PVBA, the ethenylene moiety accounts for two-dimensional (2-D) chirality upon confinement to a surface; PEBA is linear and thus 2-D achiral. Molecular films were deposited on a Ag(111) surface by organic molecular beam epitaxy and characterized by scanning tunneling microscopy. At low temperatures (around 150 K), both species form irregular networks of flat lying molecules linked via their endgroups in a diffusion-limited aggregation process. In the absence of kinetic limitations (adsorption or annealing at room temperature), hydrogen-bonded supramolecular assemblies form which are markedly different. With PVBA, enantiomorphic twin chains in two mirror-symmetric species running along a high-symmetry direction of the substrate lattice form by diastereoselective self-assembly of one enantiomer. The chirality signature is strictly correlated between neighboring twin chains. Enantiopure one-dimensional (1-D) supramolecular nanogratings with tunable periodicity evolve at intermediate coverages, reflecting chiral resolution in micrometer domains. In contrast, PEBA assembles in 2-D hydrogen-bonded islands, which are enantiomorphic because of the orientation of the supramolecular arrangements along low-symmetry directions of the substrate. Thus, for PVBA, chiral molecules form 1-D enantiomorphic supramolecular structures because of mesoscopic resolution of a 2-D chiral species, whereas with PEBA, the packing of an achiral species causes 2-D enantiomorphic arrangements. Model simulations of supramolecular ordering provide a deeper understanding of the stability of these systems.

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Section: Introductionmentioning

confidence: 97%

Stereochemical Effects in Supramolecular Self-Assembly at Surfaces: 1-D versus 2-D Enantiomorphic Ordering for PVBA and PEBA on Ag(111)

et al. 2002

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“…This was shown to result in a non-centrosymmetric thin film with the preferential order in the direction of the molecular beam. [25][26][27] Figure 1 shows the configuration of the deposition apparatus. As a base material, one sublimes amorphous supramolecular polymers of small molecules that are linked in a head-to-tail fashion by strong hydrogen bonding.…”

Section: Deposition Techniquesmentioning

confidence: 99%

Supramolecular Ordered Organic Thin Films for Nonlinear Optical and Optoelectronic Applications

Khan

Kwon

Tapponnier

et al. 2005

Adv Funct Materials

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For second‐order nonlinear optics, a supramolecularly ordered non‐centrosymmetric structure is required. Additionally, well‐ordered organic semiconducting thin films possess superior electronic properties compared to their amorphous counterparts. Herein, we firstly highlight that the design of nonlinear molecules and their functionalization for good molecular orientation (e.g., H‐bonding) is an important method in which to induce supramolecular ordering during subsequent growth. Secondly, we demonstrate a range of growth strategies (e.g., oblique‐incidence molecular beam deposition, hot‐wall deposition) for the growth of molecularly ordered thin films. Thirdly, we discuss various organic supramolecularly ordered material systems (4‐[trans(pyridin‐4‐ylvinyl)] benzoic acid, 5‐bromo‐5′‐formyl‐2,2′‐bithiophene‐4‐nitrophenyl hydrazone, tris(8‐hydroxyquinoline) aluminum) and observe the effects of molecular orientation on their nonlinear optical and optoelectronic properties.

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“…Both molecules are characterized by a pyridyl and carboxylic group giving rise to strong intermolecular hydrogen bonding verified for the sublimated powders by solid state 15 N-NMR spectroscopy. 4 A consequence of this are the rather high melting points of PEBA ͑300°C͒ and PVBA ͑350°C͒ measured by differential scanning calorimetry. 5 Hence, this class of materials is thermally very stable which is a prerequisite for any application.…”

Section: ͓S0003-6951͑99͒04221-7͔mentioning

confidence: 99%

In-plane alignment of noncentrosymmetric molecules by oblique-incidence molecular beam deposition

Müller

Cai

Kündig

et al. 1999

Applied Physics Letters

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Self-Assembly in Ultrahigh Vacuum: Growth of Organic Thin Films with a Stable In-Plane Directional Order

Cited by 45 publications

References 9 publications

Stereochemical Effects in Supramolecular Self-Assembly at Surfaces: 1-D versus 2-D Enantiomorphic Ordering for PVBA and PEBA on Ag(111)

Stereochemical Effects in Supramolecular Self-Assembly at Surfaces: 1-D versus 2-D Enantiomorphic Ordering for PVBA and PEBA on Ag(111)

Supramolecular Ordered Organic Thin Films for Nonlinear Optical and Optoelectronic Applications

In-plane alignment of noncentrosymmetric molecules by oblique-incidence molecular beam deposition

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