Opale: Status und Perspektiven

Marlow, Frank; Muldarisnur, Mulda; Sharifi, Parvin; Brinkmann, Rainer; Mendive, Cecilia B.

doi:10.1002/ange.200900210

Cited by 38 publications

(21 citation statements)

References 152 publications

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“…Furthermore, hs‐opals show clear Fabry–Perot oscillations (Figure 6) and higher‐order diffraction peaks. Both are considered as signs for good photonic crystal quality19, 21 and have not been observed before for traditional inverse opals of comparable thickness.…”

Section: Comparison Of Crack Patterns and Domain Size Of The Two Opalmentioning

confidence: 70%

“…The concept of this work is plain and simple: We avoid the inversion step which is responsible for most of the disturbances and, therefore, we expect to receive hs‐opals of similar quality as that of traditional artificial opals. Traditional artificial opals have nearly perfect domains of several hundred micrometers interrupted by cracks with a typical distance of 100 μm 21…”

Section: Comparison Of Crack Patterns and Domain Size Of The Two Opalmentioning

confidence: 99%

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Rational Molecular Design towards Vis/NIR Absorption and Fluorescence by using Pyrrolopyrrole aza‐BODIPY and its Highly Conjugated Structures for Organic Photovoltaics

Shimizu

Iino

Saeki

et al. 2014

Chemistry A European J

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Pyrrolopyrrole aza-BODIPY (PPAB) developed in our recent study from diketopyrrolopyrrole by titanium tetrachloride-mediated Schiff-base formation reaction with heteroaromatic amines is a highly potential chromophore due to its intense absorption and fluorescence in the visible region and high fluorescence quantum yield, which is greater than 0.8. To control the absorption and fluorescence of PPAB, particularly in the near-infrared (NIR) region, further molecular design was performed using DFT calculations. This results in the postulation that the HOMO-LUMO gap of PPAB is perturbed by the heteroaromatic moieties and the aryl-substituents. Based on this molecular design, a series of new PPAB molecules was synthesized, in which the largest redshifts of the absorption and fluorescence maxima up to 803 and 850 nm, respectively, were achieved for a PPAB consisting of benzothiazole rings and terthienyl substituents. In contrast to the sharp absorption of PPAB, a PPAB dimer, which was prepared by a cross-coupling reaction of PPAB monomers, exhibited panchromatic absorption across the UV/Vis/NIR regions. With this series of PPAB chromophores in hand, a potential application of PPAB as an optoelectronic material was investigated. After identifying a suitable PPAB molecule for application in organic photovoltaic cells based on evaluation using time-resolved microwave conductivity measurements, a maximized power conversion efficiency of 1.27 % was achieved.

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Section: Comparison Of Crack Patterns and Domain Size Of The Two Opalmentioning

confidence: 70%

Section: Comparison Of Crack Patterns and Domain Size Of The Two Opalmentioning

confidence: 99%

Rational Molecular Design towards Vis/NIR Absorption and Fluorescence by using Pyrrolopyrrole aza‐BODIPY and its Highly Conjugated Structures for Organic Photovoltaics

Shimizu

Iino

Saeki

et al. 2014

Chemistry A European J

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“…2D arrays and 3D superstructures of the Au NCs at different concentrations were formed by the vertical deposition method [15] on Si(111) wafers, Si(100) wafers, or glass cover slides at 60 8C and 80 % humidity. This technique was the same by which photonic crystals were formed through self-assembly of colloidal particles.…”

Section: Methodsmentioning

confidence: 99%

“…[14] The three types of Au NCs, with an average size of around 70 nm, have well-defined shapes and good monodispersity ( Figure S1 in the Supporting Information). Such Au NCs with highly uniform sizes and shapes guarantee the reproducibility of subsequent selfassembly processes.2D and 3D superstructures of Au NCs were fabricated by a vertical deposition self-assembly method, [15] which is a conventional technique for the formation of photonic crystals that are composed of colloidal particles (see the Experimental Section). [16,17] Interestingly, when the concentration of the NCs is fixed at 0.5 nm, most of the RD NCs (more than 99 %) are spontaneously and closely packed into well-defined multilayers of face-centered-cubic (fcc) structures on silicon substrates (Figure 1); each layer is a triangle and the edge length of each layer gradually decreases as the thickness increases (Figure 1 b).…”

mentioning

confidence: 99%

Superstructures and SERS Properties of Gold Nanocrystals with Different Shapes

et al. 2011

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Inorganic nanocrystal (NC) superstructures, which exhibit unique collective properties that are different to those of both the individual NCs and bulk materials, are of much scientific and technological interest. [1][2][3][4][5] For noble-metal NCs, the collective oscillation of free electrons, that is, the so-called plasmon resonance in the superstructures, provides a feasible way to realize light concentration and manipulation on a small scale.[6] Such plasmon resonance gives rise to many potential applications of noble-metal NC superstructures in different fields, for example, optical waveguides, [7] superlensing, [8] photon detection, [9] and surface-enhanced Raman scattering (SERS). Among these applications, the SERS effect based on noble-metal NC superstructures is of particular interest because of its extraordinary advantages in the highly sensitive detection of trace chemical or biological species. [10,11] The SERS effect originates from the dramatic amplification of electromagnetic fields in the NC superstructures. When the superstructures are irradiated at the wavelength that couples with the plasmon resonance of the inner NCs, the junction regions among the adjacent NCs function as "hotspots" and the local electromagnetic fields in the superstructure are amplified.[12] As a result, the Raman scattering of the detected species located at these junctions will be remarkably enhanced. Evidently, the intensity of SERS in the superstructures is determined not only by the type, shape, and size of the single NC units, but also by the inter-NC distance and arrangement pattern. Although many reports have shown that the 1D, 2D, and 3D assemblies of noble-metal NCs can be used as efficient substrates for SERS, [13] the corresponding studies on the NC superstructures are rare because of the difficulties in synthesis of monodispersed NCs that have different shapes, as well as the controlled organization of NCs on a large scale. In order to understand and maximize the SERS effect, large-scale NC superstructures with controllable morphologies are highly desirable. Herein we report how three types of Au NCs with identical sizes but different shapes can be used as building blocks to prepare superstructures on several different substrates. We demonstrate that both the structures and morphologies of the superstructures are highly dependent on the shapes of the NC units, and furthermore, that these superstructures exhibit obvious differences in their SERS properties. Both the formation mechanism and the SERS properties of the different Au NC superstructures are explored in detail.The seed-mediated growth method was used to synthesize single-crystalline rhombic dodecahedral (RD), octahedral, and cubic Au NCs by manipulating the growth kinetics of the NCs (see the Experimental Section). As reported in our previous study, RD, octahedral, and cubic Au NCs are bounded by twelve (110) planes, eight (111) planes, and six (100) planes, respectively.[14] The three types of Au NCs, with an average size of around 70 nm, have well-def...

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“…For example, monodisperse nanometer and micrometer sized spheres in a suspension can spontaneously form close-packed colloidal crystal arrays if their free volume is restricted below a certain level. [11] The surface charge of the particles must be sufficiently repulsive to discourage random aggregation but not large enough to prevent close packing. [12] The slight repulsive interactions between particles also allow them to rearrange into lower energy conformations as the free volume is decreased.…”

Section: Colloidal Crystallizationmentioning

confidence: 99%

Colloidal Assembly: The Road from Particles to Colloidal Molecules and Crystals

2010

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Colloidal particles may be considered as building blocks for materials, just like atoms are the bricks of molecules, macromolecules, and crystals. Periodic arrays of colloids (colloidal crystals) have attracted much interest over the last two decades, largely because of their unique photonic properties. The archetype opal structures are based on close-packed arrays of spheres of submicrometer diameter. Interest in structuring materials at this length scale, but with more complex features and ideally by self-assembly processes, has led to much progress in controlling features of both building blocks and assemblies. The necessary ingredients include colloids, colloidal clusters, and colloidal "molecules" which have special shapes and the ability to bind directionally, the control over short-range and long-range interactions, and the capability to place and orientate these bricks. This Review highlights recent experimental and theoretical progress in the assembly of colloids larger than 50 nm.

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Opale: Status und Perspektiven

Cited by 38 publications

References 152 publications

Rational Molecular Design towards Vis/NIR Absorption and Fluorescence by using Pyrrolopyrrole aza‐BODIPY and its Highly Conjugated Structures for Organic Photovoltaics

Rational Molecular Design towards Vis/NIR Absorption and Fluorescence by using Pyrrolopyrrole aza‐BODIPY and its Highly Conjugated Structures for Organic Photovoltaics

Superstructures and SERS Properties of Gold Nanocrystals with Different Shapes

Colloidal Assembly: The Road from Particles to Colloidal Molecules and Crystals

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