- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fingerprints of sp1 Hybridized C in the Near-Edge X-ray Absorption Spectra of Surface-Grown Materials
摘要： Carbon structures comprising sp1 chains (e.g., polyynes or cumulenes) can be synthesized by exploiting on-surface chemistry and molecular self-assembly of organic precursors, opening to the use of the full experimental and theoretical surface-science toolbox for their characterization. In particular, polarized near-edge X-ray absorption fine structure (NEXAFS) can be used to determine molecular adsorption angles and is here also suggested as a probe to discriminate sp1/sp2 character in the structures. We present an ab initio study of the polarized NEXAFS spectrum of model and real sp1/sp2 materials. Calculations are performed within density functional theory with plane waves and pseudopotentials, and spectra are computed by core-excited C potentials. We evaluate the dichroism in the spectrum for ideal carbynes and highlight the main differences relative to typical sp2 systems. We then consider a mixed polymer alternating sp1 C4 units with sp2 biphenyl groups, recently synthesized on Au(111), as well as other linear structures and two-dimensional networks, pointing out a spectral line shape specifically due to the presence of linear C chains. Our study suggests that the measurements of polarized NEXAFS spectra could be used to distinctly fingerprint the presence of sp1 hybridization in surface-grown C structures.
关键词： density functional theory,self-assembly,carbynes,on-surface chemistry,near edge X-ray absorption spectroscopy,C 1s absorption
更新于2025-09-23 15:22:29
-
Tertiary Amines Differentiated from Primary and Secondary Amines by Active Ester-Functionalized Hexabenzoperylene in Field Effect Transistors
摘要： Herein, we report two novel derivatives of hexabenzoperylene (HBP) that are functionalized with ester groups. Methyl acetate functionalized HBP (1) in single crystals self-assembles into a supramolecular nanosheet, which has a two-dimensional π-stack of HBP sandwiched between two layers of ester groups. With the same self-assembly motif, active ester-functionalized HBP (2) in field effect transistors has enabled differentiation of tertiary amines from primary and secondary amines, in agreement with the fact that active ester reacts with primary and secondary amines but not with tertiary amines to form amides.
关键词： sensors,organic field effect transistors,organic semiconductors,self-assembly,arenes
更新于2025-09-23 15:22:29
-
A fast method for preparing a large diameter, three-dimensional photonic crystal infrared stealth material
摘要： With the development of infrared detection technology, the threat of infrared detection technology to military targets in the battle?eld is becoming more and more serious. Novel infrared stealth materials are in urgent demand. Photonic crystals are promising infrared stealth materials because they can prohibit the propagation of electromagnetic waves in a certain frequency range. This paper outlines a simple and fast method to fabricate three-dimensional photonic crystals for stealth material. Monodisperse polystyrene colloid microspheres with a particle size of 2 μm were prepared and used in a gas–liquid interface self-assembly to form a three-dimensional photonic crystal infrared stealth material. The infrared absorption peak wavelengths of the material were 3.30 μm and 3.42 μm. The band gap is in good agreement with the photon forbidden band (3.24–3.44 μm) obtained from simulation and calculation using Rsoft software. The material meets the requirements of an infrared stealth material and realizes the modulation of the infrared radiation characteristics of the detectable band of 3–5 μm. The process provides a simple, economical, fast, and e?cient new method for the preparation of large diameter, three-dimensional photonic crystal infrared stealth materials.
关键词： Photonic crystal,Infrared stealth,Gas/liquid interface self-assembly
更新于2025-09-23 15:22:29
-
Marangoni interface self-assembly hybrid carbon nano-network for transparent conductive silicone rubber
摘要： Inspired by compact one-dimensional (1D) and two-dimensional (2D) hybrid network like natural thrombosis and beaver’s dam, we use Marangoni interface self-assembly hybrid 1D carbon nanotube and 2D graphene (CNT+G) as continuously connected nano-network onto the surface of silicone ink coated silicone rubber. Both good optical transmittance and electrical conductivity demonstrated in the transparent conductive silicone rubber (TCSR). Besides, the TCSR also have excellent mechanical adhesion between the (CNT+G) film and silicone ink coated silicone rubber.
关键词： Adhesion,Marangoni interface self-assembly,Graphene,CNT,Transparent conductive silicone rubber
更新于2025-09-23 15:22:29
-
Self-assembly of fractal liquid crystal colloids
摘要： Nematic liquid crystals are anisotropic fluids that self-assemble into vector fields, which are governed by geometrical and topological laws. Consequently, particulate or droplet inclusions self-assemble in nematic domains through a balance of topological defects. Here, we use double emulsions of water droplets inside radial nematic liquid crystal droplets to form various structures, ranging from linear chains to three-dimensional fractal structures. The system is modeled as a formation of satellite droplets, distributed around a larger, central core droplet and we extend the problem to explain the formation of fractal structures. We show that a distribution of droplet sizes plays a key role in determining the symmetry properties of the resulting geometric structures. The results are relevant to a variety of inclusions, ranging from colloids suspensions to multi-emulsion systems. Such systems have potential applications for novel switchable photonic structures as well as providing wider insights into the packing of self-assembled structures.
关键词： Self-assembly,Fractal structures,Topological defects,Colloids,Liquid crystals
更新于2025-09-23 15:22:29
-
Low-cost light manipulation coatings for polymer solar cell photocurrent increase under various incident angles
摘要： We fabricate self-assembled templates to produce textured polydimethylsiloxane (PDMS) with quasi-random dimension distributions which are employed as light manipulation coatings in polymer solar cells (PSCs). When deposited at the PSC glass/air interface, PDMS films with microdome-like structures enhance the short-circuit current density (Jsc) by 7.9% through combined anti-reflective and scattering effects. The PSC power conversion efficiency can thus be improved from 6.75% to 7.28% and a maximum Jsc increase of 21% is observed for incident light tilted by 30 degrees. We compare structures with different diameter dispersities and confirm that quasi-randomness in textured coatings can increase their light scattering ability.
关键词： Nanofabrication,self-assembly,light manipulation,polymer solar cells
更新于2025-09-23 15:22:29
-
Photonic Titanium dioxide film obtained from hard template with chiral nematic structure for environmental application
摘要： In the present work, mesoporous TiO2 with a photonic structure was elaborated using cellulose nanocrystals (CNCs) as a biotemplate by two-step hard template methods. This strategy enables to replicate the chiral nematic (CN) structure of the photonic films (biotemplate) in TiO2 films. A series of iridescent CNCs films with different weight ratios of silica/CNCs composite photonic films were prepared via evaporation induced self-assembly (EISA) method. The films showed iridescent color and tuneable Bragg reflection wavelengths by solely changing the ratio between the silica and the CNCs biotemplate. Polarized optical microscopy (POM) performed on hydride SiO2/CNCs films showed a birefringence and typical fingerprint of chiral nematic structure. This birefringence was also observed for TiO2 films obtained using SiO2 films as a hard template, which suggested the transfer of the chiral nematic structure in TiO2 materials. Afterwards, their optical, morphological and electronic properties were studied by scanning electron microscope (SEM), POM, energy-dispersive X-ray spectroscope (EDX) and time resolved microwave conductivity (TRMC). The photocatalytic activities were evaluated by following the phenol degradation using high performance liquid chromatography (HPLC). The results showed that the structuration of the TiO2 film using a chiral nematic SiO2 film as hard template enhances the photocatalytic performance compared to non-structured mesoporous TiO2.
关键词： hard template,cellulose nanocrystals,iridescent film,evaporation induced self-assembly,light harvesting,phenol degradation,chiral nematic structure
更新于2025-09-23 15:22:29
-
AIE-active Metal-organic Coordination Complexes Based on Tetraphenylethylene Unit and Their Applications
摘要： Tetraphenylethylene (TPE) and its derivatives, as the widely used aggregation-induced emission (AIE) fluorophores, have attracted rapidly growing interest in the fields of material science and biological technology due to their unique light-emitting mechanism—they are nearly non-emissive in dilute solution but emit brilliant fluorescence in the aggregate state because of the restriction of intramolecular motion. Coordination-driven self-assembly, which provides a highly effective method to put the individual chromophores together, is consistent with the AIE mechanism of TPE. During the past few years, some AIE-active metal-organic coordination complexes have been successfully constructed via coordination-driven self-assembly, and their AIE properties and applications have been investigated. In this review, we survey the recent progress on TPE-based metal-organic coordination complexes and their applications in fluorescence sensors, cell imaging, and light-emitting materials. We will introduce them from three different types of structures: metallacycles, metallacages, and metal-organic frameworks (MOFs).
关键词： Tetraphenylethylene,Self-assembly,Aggregation-induced emission,Sensor,Metal-organic coordination complexes
更新于2025-09-23 15:22:29
-
Ordered Particle Arrays via a Langmuir Transfer Process: Access to Any Two-Dimensional Bravais Lattice
摘要： We demonstrate how to directly transform a close-packed hexagonal colloidal monolayer into non-close packed particle arrays of any two-dimensional symmetry at the air/water interface. This major advancement in the field of nanoparticle self-assembly is based on a simple one-dimensional stretching step in combination with the particle array orientation. Our method goes far beyond existing strategies and allows access to all possible 2D Bravais lattices. A key element of our work is the possibility to macroscopically stretch a particle array in a truly one-dimensional manner, which has not been possible up to now. We achieve this by stretching the nanoparticle array at an air/water interface during the transfer process. The degree of stretching is simply controlled by the wettability of the transfer substrate. To retain the symmetry of the transferred structure, the capillary forces upon drying have to be circumvented. We demonstrate two concepts based on thermal fixation for this. It allows for the first time to fabricate non-close packed, non-hexagonal colloidal monolayers on a macroscopic length scale.
关键词： guided assembly,interfacial self-assembly,colloidal self-assembly,non-close-packed monolayers
更新于2025-09-23 15:21:21
-
Self-Assembly of Amphiphilic Schiff Base and Selectively Turn on Circularly Polarized Luminescence by Al3+
摘要： We designed glutamide-derived amphiphilic Schiff bases containing three different aldehyde moieties for the fabrication of circularly polarized luminescence (CPL) emitting materials. Upon self-assembly in acetonitrile, Schiff bases featuring 4-(dimethylamino)-2-hydroxylbenzaldehyde and 1-hydroxy-2-naphthaldehyde groups form supramolecular gels with twist and fiber structures, respectively, while Schiff bases featuring 2-hydroxy-1-naphthaldehyde groups forms precipitation with flakes structures. Although emission and circular dichroism (CD) signals can be detected from the supramolecular gels formed by amphiphilic Schiff bases, none of them exhibits circularly polarized luminescence (CPL). While Mg2+, Zn2+ and Al3+ can both significantly enhance the fluorescence of the Schiff bases, interestingly, only Al3+ ion is able to turn on the CPL emission. This study on the one hand provides a simple method to the fabrication of CPL emitting supramolecular materials, and on the other hand offers a novel way to the sensing of aluminum ion with supramolecular materials.
关键词： Self-assembly,Schiff bases,Circularly polarized luminescence,Al3+,Supramolecular gels
更新于2025-09-23 15:21:21