scholarly journals Homochiral Supramolecular Thin Film from Self-Assembly of Achiral Triarylamine Molecules by Circularly Polarized Light

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 402
Author(s):  
Changjun Park ◽  
Jinhee Lee ◽  
Taehyoung Kim ◽  
Jaechang Lim ◽  
Jeyoung Park ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Self Assembly ◽  
Polarized Light ◽  
Building Blocks ◽  
The Self ◽  
Assembly Process ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Self Assembled

Here, we report the formation of homochiral supramolecular thin film from achiral molecules, by using circularly polarized light (CPL) only as a chiral source, on the condition that irradiation of CPL does not induce a photochemical change of the achiral molecules. Thin films of self-assembled structures consisting of chiral supramolecular fibrils was obtained from the triarylamine derivatives through evaporation of the self-assembled triarylamine solution. The homochiral supramolecular helices with the desired handedness was achieved by irradiation of circularly polarized visible light during the self-assembly process, and the chiral stability of supramolecular self-assembled product was achieved by photopolymerization of the diacetylene moieties at side chains of the building blocks, with irradiation of circularly polarized ultraviolet light. This work provides a novel methodology for the generation of homochiral supramolecular thin film from the corresponding achiral molecules.

scholarly journals Multilayer Self-Assemblies as Electronic and Optical Materials

1997 ◽  
Vol 488 ◽  
Author(s):  
DeQuan Li ◽  
M. Lütt ◽  
Xiaobo Shi ◽  
M. R. Fitzsimmons
Keyword(s):  
Thin Film ◽  
Self Assembly ◽  
Film Growth ◽  
Building Blocks ◽  
Layer Growth ◽  
The Self ◽  
Growth Surface ◽  
Layer By Layer ◽  
Self Assembled ◽  
Average Electron

AbstractThe layer-by-layer growth of film structures consisting of sequential depositions of oppositely charged polymers and macrocycles (ring-shaped molecules) have been constructed using molecular self-assembly techniques. These self-assembled thin films were characterized with X-ray reflectometry, which yielded (1) the average electron density, (2) the average thicknesses, and (3) the roughness of the growth surface of the self-assembled multilayer of macrocycles and polymers. These observations suggest that inorganic-organic interactions play an important role during the initial stages of thin-film growth, but less so as the thin film becomes thicker. Optical absorption techniques were also used to characterize the self-assembled multilayers. Phorphyrin and phthalocyanine derivatives were chosen as the building blocks of the self-assembled multilayers because of their interesting optical properties.

scholarly journals Self-Assembly of Shape-Tunable Oblate Colloidal Particles into Orientationally Ordered Crystals, Glassy Crystals and Plastic Crystals

Soft Matter ◽  
2021 ◽  
Author(s):  
Jiawei Lu ◽  
Xiangyu Bu ◽  
Xinghua Zhang ◽  
Bing Liu
Keyword(s):  
Crystal Structures ◽  
Self Assembly ◽  
Colloidal Particles ◽  
Building Blocks ◽  
Fundamental Question ◽  
The Self ◽  
Plastic Crystals ◽  
Self Assembled ◽  
Glassy Crystals ◽  
The Relationship

The shapes of colloidal particles are crucial to the self-assembled superstructures. Understanding the relationship between the shapes of building blocks and the resulting crystal structures is an important fundamental question....

Controllable Synthesis of Cobalt Porphyrin Nanocrystals through Micelle Confinement Self-Assembly

MRS Advances ◽  
2020 ◽  
Vol 5 (42) ◽  
pp. 2147-2155
Author(s):  
Sudi Chen ◽  
Xitong Ren ◽  
Shufang Tian ◽  
Jiajie Sun ◽  
Feng Bai
Keyword(s):  
Self Assembly ◽  
Water Oxidation ◽  
Separation Efficiency ◽  
Noncovalent Interactions ◽  
Building Blocks ◽  
The Self ◽  
Hexagonal Prism ◽  
Assembly Process ◽  
Surfactant Micelles ◽  
Cobalt Porphyrin

AbstractThe self-assembly of optically active building blocks into functional nanocrystals as high-activity photocatalysts is a key in the field of photocatalysis. Cobalt porphyrin with abundant catalytic properties is extensively studied in photocatalytic water oxidation and CO2 reduction. Here, we present the fabrication of cobalt porphyrin nanocrystals through a surfactant-assisted interfacial self-assembly process using Co-tetra(4-pyridyl) porphyrin as building block. The self-assembly process relies on the combined noncovalent interactions such as π-π stacking and axial Co-N coordination between individual porphyrin molecules within surfactant micelles. Tuning different reaction conditions (temperature, the ratio of co-solvent DMF) and types of surfactant, various nanocrystals with well-defined 1D to 3D morphologies such as nanowires, nanorods and nano hexagonal prism were obtained. Due to the ordered accumulation of molecules, the nanocrystals exhibit the properties of the enhanced capability of visible light capture and can conduce to improve the transport and separation efficiency of the photogenerated carriers, which is important for photocatalysis. Further studies of photocatalytic CO2 reduction are being performed to address the relationship between the size and shape of the nanocrystals with the photocatalytic activity.

scholarly journals Modification of a Single Atom Affects the Physical Properties of Double Fluorinated Fmoc-Phe Derivatives

2021 ◽  
Vol 22 (17) ◽  
pp. 9634
Author(s):  
Moran Aviv ◽  
Dana Cohen-Gerassi ◽  
Asuka A. Orr ◽  
Rajkumar Misra ◽  
Zohar A. Arnon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Physical Properties ◽  
Self Assembly ◽  
Deep Understanding ◽  
Building Blocks ◽  
The Self ◽  
Single Atom ◽  
Supramolecular Organization ◽  
Assembly Process ◽  
Wide Range

Supramolecular hydrogels formed by the self-assembly of amino-acid based gelators are receiving increasing attention from the fields of biomedicine and material science. Self-assembled systems exhibit well-ordered functional architectures and unique physicochemical properties. However, the control over the kinetics and mechanical properties of the end-products remains puzzling. A minimal alteration of the chemical environment could cause a significant impact. In this context, we report the effects of modifying the position of a single atom on the properties and kinetics of the self-assembly process. A combination of experimental and computational methods, used to investigate double-fluorinated Fmoc-Phe derivatives, Fmoc-3,4F-Phe and Fmoc-3,5F-Phe, reveals the unique effects of modifying the position of a single fluorine on the self-assembly process, and the physical properties of the product. The presence of significant physical and morphological differences between the two derivatives was verified by molecular-dynamics simulations. Analysis of the spontaneous phase-transition of both building blocks, as well as crystal X-ray diffraction to determine the molecular structure of Fmoc-3,4F-Phe, are in good agreement with known changes in the Phe fluorination pattern and highlight the effect of a single atom position on the self-assembly process. These findings prove that fluorination is an effective strategy to influence supramolecular organization on the nanoscale. Moreover, we believe that a deep understanding of the self-assembly process may provide fundamental insights that will facilitate the development of optimal amino-acid-based low-molecular-weight hydrogelators for a wide range of applications.

Terahertz Emission from Bismuth Thin Films Induced by Excitation with Circularly Polarized Light

2020 ◽  
Vol 14 (6) ◽  
Author(s):  
Yoshua Hirai ◽  
Naotaka Yoshikawa ◽  
Hana Hirose ◽  
Masashi Kawaguchi ◽  
Masamitsu Hayashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Polarized Light ◽  
Terahertz Emission ◽  
Circularly Polarized Light ◽  
Circularly Polarized

Self-Assembled Luminescent Quantum Dots To Generate Full-Color and White Circularly Polarized Light

2017 ◽  
Vol 129 (40) ◽  
pp. 12342-12346 ◽  
Author(s):  
Shengwei Huo ◽  
Pengfei Duan ◽  
Tifeng Jiao ◽  
Qiuming Peng ◽  
Minghua Liu
Keyword(s):  
Quantum Dots ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Full Color ◽  
Self Assembled ◽  
Luminescent Quantum Dots

scholarly journals Self-assembled peptide nanostructures for electrical, optical, and magnetic applications

2018 ◽  
Author(s):  
◽  
Soma Khanra
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Nonlinear Optical ◽  
Electronic Devices ◽  
Longitudinal Component ◽  
The Self ◽  
Assembly Process ◽  
Experimental Characterization ◽  
X Ray ◽  
Self Assembled

Bio-nanotechnology has become a widespread exciting field of research as the basic biological structure of bio-inspired materials and nanotechnology share the common length scale. Bio-nanotechnology, which is mainly based on bio-inspired nanostructured materials, has potential applications in nanomedicine, drug delivery, bio-sensors, and bio-degradable electronic devices. The nanostructures obtained from biomolecules are attractive due to their biocompatibility for molecular recognition, ease of chemical modification, and the ability to scaffold other organic and inorganic materials. Peptide nanostructures formed through the self-assembly process of the basic building block of diphenylalanine show promising applications in biodegradable electronic devices, drug delivery, catalysis agent, waveguide, and frequency converter. This research focusses on the self-assembly process in a dipeptide, L, L diphenylalanine (FF) and exploring its electronic, optical, and magnetic properties. The role of solvents in the self-assembly process of FF is explored by combining density functional theory (DFT) along with experimental characterization techniques such as electron microscopy, Raman scattering, and x-ray diffraction (XRD). One of the objectives of this work was to explore the nonlinear optical (NLO) properties of FF nanostructures via second harmonic generation (SHG). The ratio of the nonlinear optical coefficients was obtained from individual FF nanotubes as a function of the tube diameter and thermal annealing conditions. The ratio of the shear to the longitudinal component (d15/d33) of the NLO coefficient increases with the diameter of the tubes. One of the transverse components, d31, of the NLO coefficient is found to be negative, and its magnitude with respect to the longitudinal component (d33) increases with the tube diameter. Thermal treatment of individual FF tubes has a similar effect as increasing the diameter of the tubes in SHG polarimetry. The functionalization of FF micro-nanostructures (FF-MNS) with nanomaterials was studied. FF-MNS with Ag or Au nanoparticles were explored in surface-enhanced Raman scattering (SERS). Such self-assembled nanostructures provide a natural template for tethering Au and Ag nanoparticles (Nps) due to its fractal surface. The FF-MNS undergo an irreversible phase transition from hexagonal packing (hex) to an orthorhombic (ort) structure at [about] 150 [degree]C. The metal Nps form chains on hex FF-MNS as inferred from transmission electron microscopy images and a uniform non-aggregated distribution in the ort phase. The SERS spectra obtained from R6G bound to FF-MNSs with AuNps show a higher enhancement for the ort phase compared with the hex phase. The experimental results agree well with our calculated Raman spectra of model systems using DFT. Our results indicate that FF-MNS both in the hex and ort phase can be used as substrates for SERS analysis with different metal Nps, opening up a novel class of optically active bio-based substrates. The use of magnetic nanoparticles with biomolecules offers a versatile path for tuning the functionality of the composite material for several applications. The functionalization of FF-MNS with cobalt ferrite (CFO) magnetic nanoparticles was achieved. The interaction between CFO nanoparticles and FF-MNS was investigated by optical spectroscopy, x-ray photoelectron spectroscopy (XPS), and magnetization measurements. The changes in the XPS data from pristine FF-MNS and CFO:FF-MNS are indicative of a charge transfer process from CFO to FF-MNS, changing the electronic states of the Fe2+ and Co2+ ions. A comparison of the magnetic characterization from CFO nanoparticles and CFO:FF-MNS shows a higher saturation magnetization from the nanocomposite sample, which is attributed to a change in the cationic distribution in CFO upon binding with the peptide. We were further successful in demonstrating the application of FF-MNS as a bio-degradable active layer in an organic light emitting diode (OLED). FF-MNS were functionalized with two blue-emitting conducting polymers: di-octyl-substituted polyfluorene (PF8) and ethyl-hexyl polyfluorene (PF2/6), and used as an active layer in an OLED architecture. A combination of molecular dynamics and experimental characterization techniques reveals a stronger binding mechanism for PF8 compared to PF2/6 with FF-MNS. Biodegradability tests from FF-MNS:PF8 nanocomposite films show more than 80% weight loss in 2 h by enzymatic action compared to PF8 pristine films, which do not degrade. Self-assembled FF-MNS with organic semiconductors open up a new generation of biocompatible and biodegradable materials in organic electronics.

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