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(Poly)terephthalates with Efficient Blue Emission in the Solid State
摘要： We prepared dimethyl and diaryl 2,5-dialkoxyterephthalates from dimethyl 2,5-dihydroxyterephthalate in good-to-high yields via alkylation or a sequence of alkylation, hydrolysis, chlorination, and condensation. The absorption spectra of the dialkoxyterephthalates contain a small band at 332–355 nm, which could be assigned to intramolecular charge-transfer transition from the alkoxy to alkoxycarbonyl groups on the basis of theoretical calculations using density functional theory. The dialkoxyterephthalates exhibited blue fluorescence with moderate-to-excellent quantum yields not only in solution but also in the solid state, such as a poly(methyl methacrylate) (PMMA) film and a powder. The solid-state quantum yields of the diisopropoxy-substituted terephthalates were similar or considerably higher than those of the dimethoxy-substituted counterparts. Copolymerization of 2,5-diisopropoxyterephthaloyl chloride and 1,4-butanediol with or without terephthaloyl chloride gave brilliantly blue fluorescent polymers, whose quantum yields were 0.72 and 0.71 in toluene and 0.46 and 0.40 in the neat film, respectively. Furthermore, white emission was achieved when a fluorescent yellow 2,5-diaminoterephthalate was doped into the thin film of the blue fluorescent polymer at 0.4 wt %.
关键词： materials science,arenes,donor-acceptor systems,conjugation,fluorescence
更新于2025-09-23 15:23:52
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Data on ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications
摘要： Characterization data of fluorescent nanoparticles made of cellulose acetate (CA-dots) are shown. The data in this article accompanies the research article “Data on ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications” [1]. The measurements and calculation of brightness of individual CA-dots are presented. The description of conjugation procedure Pluronic F127-Folic Acid copolymer and folic acid is shown. Identification of composition of CA dots using Raman and absorbance spectroscopy is demonstrated. The methods for image analysis of efficiency of CA-dot targeting of epithelial tumors xenografted in zebrafish is presented.
关键词： Materials Science,Cellulose acetate fluorescent nanoparticles
更新于2025-09-23 15:19:57
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Visualization of materials using the confocal laser scanning microscopy technique
摘要： The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.
关键词： confocal laser scanning microscopy,reaction processes,internal structures,materials science,surface structures,spatial structures,visualization
更新于2025-09-19 17:13:59
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Microwave Synthesis of a Prominent LED Phosphor for School Students: Chemistry’s Contribution to Sustainable Lighting
摘要： Scarcer raw materials and climate change are scienti?c facts that make it necessary to enhance energy e?ciency and to recycle raw material. Fundamental researchers at universities as well as in industry agree that light-emitting diodes (LEDs) are the most e?cient and sustainable light sources of the future. Chemistry plays a signi?cant role in the development of white, energy-e?cient LEDs; however, students and society do not seem aware of this role. This paper presents a school-student-friendly synthesis of cerium-doped yttrium aluminum garnet (YAG:Ce) in a laboratory microwave oven. YAG:Ce is the most widely applied luminescent material (“phosphor”) used in white LEDs. The initial blue light of a gallium nitride-based primary LED is partly down-converted by the YAG:Ce phosphor on top of the LED chip, resulting in yellow-green emission. Additive color mixing (blue + yellow-green) results in cold-white light generation. This experiment aims to demonstrate chemistry’s contribution to sustainable development in a comprehensible way. On the basis of such phosphor-converted LEDs, the interdependence of and cooperation between di?erent scienti?c disciplines are outlined. The critical question of the related raw materials, in this case especially rare earth elements (REEs), their lifetime, and their possible recycling, represents another important issue for sustainable development and systems thinking and is shown in this example from everyday life.
关键词： Systems Thinking,Materials Science,High School/Introductory Chemistry,Sustainability,Green Chemistry,Curriculum
更新于2025-09-19 17:13:59
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Structural characterization of Argania spinosa Moroccan wooden artifacts during natural degradation progress using infrared spectroscopy (ATR-FTIR) and X-Ray diffraction (XRD)
摘要： The present work is focused on spectroscopic study of four samples of Argan wooden artifact pertaining to the 17th, 18th, 20th and 21st centuries. The objective is to characterize their unknown structures by the study of their non degraded parts and to investigate changes occurred in their degraded parts due to the natural degradation process. Attenuated total re?ectance Fourier transform infrared spectroscopy gauges the presence of many functional groups related to cellulose I and/or II (OH, C–O–C and –CH2), hemicelluloses (particularly C?O (cid:2)1), and lignin (OH phenolic, Car-O and C?Car) and provides qualitative information on the state of wood alteration by informing on the evolution of new former C?O bands. The degree of conversion to carbonyl group, especially quinone or p-quinone at 1650 cm (cid:2)1, is correlated to lignin degradation, while the absence of the C?O acetoxy absorption is ascribable to occurred deterioration in hemicelluloses, and (cid:2)1. X-ray diffraction determines the presence of two forms of cellulose; amorphous cellulose at 18.5(cid:3) 2θ and predominant crystalline cellulose Iβ at 2θ ? 22.6(cid:3) which characterized by an intense peak. The decrease of crystallinity index values con?rms the deterioration level and obvious changes in crystallinity level. However, the microcrystalline structure appears unaltered because no signi?cant changes were observed for calculated cristallite seize. The obtained results depend on the prolonged time of ageing, natural deterioration phenomena, and wood part (internal or external) that is exposed to degradation. The combination of these two methods is useful for an accurate estimation of the degradation level of argan wood.
关键词： Chemistry,Argan wood artifact,XRD,Analytical chemistry,Natural product chemistry,Materials Chemistry,Natural degradation,Archaeology,ATR-FTIR spectroscopy,Crystallinity,Lignocelluloses,Structural characterization,Materials Science,Organic chemistry
更新于2025-09-12 10:27:22
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A study of the influence of plasmonic resonance of gold nanoparticle doped PEDOT: PSS on the performance of organic solar cells based on CuPc/C60
摘要： This work studied the role of gold nanoparticles (AuNPs) with different spherical sizes mixed with poly (3, 4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT: PSS) as a hole transfer layer to enhance the efficiency (ITO/PEDOT:PSS (AuNPs)/CuPc/C60/Al) organic photovoltaic cell (OPV). AuNPs were synthesized using the thermochemical method and the results of the transmission electron microscope (TEM) images showed that the gold nanoparticles mostly dominated by spherical shapes and sizes were calculated in the range (12–23 nm). Measurements of UV-VIS spectra for AuNPs have shown that the surface plasmon resonance shifted to a higher wavelength with decreasing the particle size. Surface morphology and absorption spectra of OPV cells were studied using atomic force microscope and UV-VIS spectrometer techniques. The efficiency of the OPV cell was calculated without and with AuNPs. Efficiency was increased from 0.78% to 1.02% due to the embedded of AuNPs with (12 nm) in PEDOT/PSS. The increase in the light absorption in CuPc is due to the good transparent conducting of PEDOT:PSS and the increase in the electric field around AuNPs embedded in PEDOT:PSS and inbuilt electric field at the interfacial between CuPc and C60 is due to the surface plasmon resonance of AuNPs. The increase in these two factors increase the exciton generation in CuPc, dissociation at the interfacial layer, and charge carrier transfer which increases the collection of electrons and holes at cathode and anode.
关键词： Copper phthalocyanine,PEDOT:PSS,Solar cell,Gold nanoparticles,Materials chemistry,Fullerene,Materials science
更新于2025-09-11 14:15:04
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Crosslinkable Bis(diphenylamine)‐Substituted Mixed Dihydroindeno[1,2‐b]fluorenes for Solution‐Processed, Multilayer OLEDs
摘要： The synthesis and application of a series of crosslinkable bis(diphenylamine)-substituted mixed dihydroindeno[1,2-b]fluorenes as model systems for the fabrication of solution-processed, multilayer OLEDs is described. Introducing a novel functionalization approach by C(sp3)-C(sp2) Suzuki-Miyaura reactions, the synthesis is based on a modular strategy, leading to eight nearly isoelectronic derivatives which allow for the observation of structure-property-relationships in the context of crosslinkable hole-transport materials, e.g. for use in organic light-emitting diodes (OLEDs). By systematically altering structural parameters, such as the number of crosslinkable oxetane moieties per molecule (2-6 moieties) and their position of attachment (geminal and/or lateral), process relevant thermal properties such as thermal stability and glass-transition temperature can be influenced and allow for the investigation of their impact on the crosslinking behavior and the resulting device performance.
关键词： polymerization,materials science,crosslinking,oxetane,OLED
更新于2025-09-11 14:15:04
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Radiology, Lasers, Nanoparticles and Prosthetics || 15. Prosthetics
摘要： When body parts and functions fail there are two possibilities for remedy: regeneration or replacement. Regeneration is always the better option. However, if by any reason this option is not available, replacement by a donor or by artificial parts is the second best choice. In this chapter we consider artificial replacements, called prostheses. Prostheses may replace limbs or organs and are supposed to take over as well as possible the function of the healthy organ. We distinguish between two types of prosthesis: Exoprosthesis, prosthesis external to the body; Endoprosthesis, prosthesis within the body, also called implants.
关键词： computer technology,electronics,implants,exoprosthesis,prostheses,biomechanics,biomedicine,endoprosthesis,materials science,bionics
更新于2025-09-11 14:15:04
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Microscopy: Hasten high resolution
摘要： The best electron and scanning probe microscopes today can resolve individual atoms and chemical bonds. Views of materials such as graphene, catalysts and oxides on these scales — around 0.5 ?ngstr?ms — reveal structures and the impacts of crystal defects on their properties. To truly understand materials’ chemical and physical properties, atomic arrangements need to be mapped with much greater precision. Resolutions of 0.1 ? — the goal set by physicist Richard Feynman in his 1959 American Physical Society lecture, ‘There’s Plenty of Room at the Bottom’ — would take us to the physical limit of microscope vision, set by the thermal vibrations of atoms. Small structural distortions that determine magnetism, valence (the number of chemical bonds an atom can form) and spin state would become apparent.
关键词： atomic resolution,materials science,scanning probe microscopy,electron microscopy,microscopy
更新于2025-09-11 14:15:04
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Growth and anisotropy of transport properties of CuGaSe2 single crystals
摘要： Single crystals of ????????????2 are prepared by a technique based on the vertical Bridgman procedure. The crystal chemical and phase compositions were identi?ed by using dispersive X-ray ?uorescence spectrometry and X-ray di?raction data analysis, respectively. The Hall e?ect and the electrical conductivity were determined in terms of temperature, parallel and orthogonal to the layer surface, and the parameters proved to be strongly anisotropic. From carried out measurements, di?erent parameters such like the carrier mobilities, the carrier concentration, the relaxation time, the di?usion coe?cient, and the length of di?usion for both, majority carriers and minority carriers were estimated.
关键词： Condensed matter physics,Materials science,Electromagnetism
更新于2025-09-10 09:29:36