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Chemical luminescence

Linzhong Wu, Huicheng Hu, Yong Xu, Shu Jiang, Min Chen, Qixuan Zhong, Di Yang, Qipeng Liu, Yun Zhao, Baoquan Sun, Qiao Zhang, Yadong Yin
We report a novel CsX-stripping mechanism which enables efficient chemical transformation of non-luminescent Cs4PbX6 (X = Cl, Br, I) nanocrystals (NCs) to highly luminescent CsPbX3 NCs. During the transformation, Cs4PbX6 NCs dispersed in a nonpolar solvent are converted into CsPbX3 NCs by stripping CsX through an interfacial reaction with water in a different phase. This process takes advantage of the high solubility of CsX in water as well as the ionic nature and high ion diffusion property of Cs4PbX6 NCs, and produces monodisperse and air-stable CsPbX3 NCs with controllable halide composition, tunable emission wavelength covering the full visible range, narrow emission width, and high photoluminescent quantum yield (up to 75%)...
August 14, 2017: Nano Letters
Bin Liu, Xiaoran Deng, Zhongxi Xie, Ziyong Cheng, Piaoping Yang, Jun Lin
Oleic acid (OA) and/or oleylamine (OAm) are generally used as the surface ligands for stabilization of inorganic nanocrystals (NCs). The hydrophobic and inert surface of the NCs limits their applications such as in biomedical areas. Hence, surface modifications are essential in many physical and chemical processes. Here, a facile and versatile strategy is reported for the modification of NCs by ultraviolet-induced thiol-ene chemistry, in which thiol-terminated poly(ethylene glycol) (HSPEG) and its derivatives can react directly with double bonds in OA/OAm ligands to form covalent linking within one step...
August 10, 2017: Advanced Materials
Dongke Li, Yicheng Jiang, Jingjing Liu, Pei Zhang, Jun Xu, Wei Li, Kunji Chen
Here, we report the enhanced luminescence and optical gain by appropriate P doping in Si nanocrystals/SiO2 multilayers with ultra-small size of ~1.9nm. The luminescence intensity is enhanced by 19.4% comparing with that of un-doped one and the optical gain is as high as 171.8 cm-1, which can be attributed to the reduction of surface defect states by the passivation of P impurities as reveled by electron spin resonance spectra. Further increasing the P doping ratios results in the increase of conduction electrons due to the substitutionally doping of phosphorus into the Si NCs, which favors the Auger recombination process...
August 9, 2017: Nanotechnology
Yingxian Xue, Chengjie Ding, Youying Rong, Qiang Ma, Chengda Pan, E Wu, Botao Wu, Heping Zeng
Plasmonic enhancement induced by metallic nanostructures is an effective strategy to improve the upconversion efficiency of lanthanide-doped nanocrystals. It is demonstrated that plasmonic enhancement of the upconversion luminescence (UCL) of single NaYF4 :Yb(3+) /Er(3+) /Mn(2+) nanocrystal can be tuned by tailoring scattering and absorption cross sections of gold nanorods, which is synthesized wet chemically. The assembly of the single gold nanorod and single upconversion nanocrystal is achieved by the atomic force microscope probe manipulation...
August 7, 2017: Small
Hendrik C Swart
The important role of surface sensitive characterization techniques such as Auger electron spectroscopy (AES), X-ray photo electron spectroscopy (XPS), time of flight scanning ion mass spectrometry (TOF-SIMS) and High resolution transmission electron microscopy (HRTEM) for the characterization of different phosphor materials is discussed in this short review by giving selective examples from previous obtained results. AES is used to monitor surface reactions during electron bombardment and also to determine the elemental composition of the surfaces of the materials, while XPS and TOF-SIMS are used for determining the surface chemical composition and valence state of the dopants...
August 4, 2017: Materials
Ye Du, Xiao-Tong Lv, Qian-Yuan Wu, Da-Yin Zhang, Yu-Ting Zhou, Lu Peng, Hong-Ying Hu
Chlorination is essential to the safety of reclaimed water; however, this process leads to concern regarding the formation of disinfection byproducts (DBPs) and toxicity. This study reviewed the formation and control strategies for DBPs and toxicity in reclaimed water during chlorination. Both regulated and emerging DBPs have been frequently detected in reclaimed water during chlorination at a higher level than those in drinking water, indicating they pose a greater risk to humans. Luminescent bacteria and Daphnia magna acute toxicity, anti-estrogenic activity and cytotoxicity generally increased after chlorination because of the formation of DBPs...
August 2017: Journal of Environmental Sciences (China)
Tsung-Yuan Chang, Chih-Min Wang, Tai-Yuan Lin, Hsiu-Mei Lin
The increasing volume and complexity of waste associated with the modern economy poses a serious risk to ecosystems and human health. However, the remanufacturing and recycling of waste into usable products can lead to substantial resource savings. In the present study, clam shell waste was first transformed into pure and well-crystallized single-phase white light-emitting phosphor Ca₉Gd(PO₄)₇:Eu(2+),Mn(2+) materials. The phosphor Ca₉Gd(PO₄)₇:Eu(2+),Mn(2+) materials were synthesized by the solid-state reaction method and the carbothermic reduction process, and then characterized and analyzed by means of X-ray diffraction (XRD) and photoluminescence (PL) measurements...
December 2, 2016: Materials
Brian Ford, Natasha Tabassum, Vasileios Nikas, Spyros Gallis
The following study focuses on the photoluminescence (PL) enhancement of chemically synthesized silicon oxycarbide (SiCxOy) thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD), and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H₂, 95% N₂) ambients, modifying the observed white light emission...
April 23, 2017: Materials
Alessia Artesani, Francesca Gherardi, Austin Nevin, Gianluca Valentini, Daniela Comelli
It is known that oil paintings containing zinc white are subject to rapid degradation. This is caused by the interaction between the active groups of binder and the metal ions of the pigment, which gives rise to the formation of new zinc complexes (metal soaps). Ongoing studies on zinc white paints have been limited to the chemical mechanisms that lead to the formation of zinc complexes. On the contrary, little is known of the photo-physical changes induced in the zinc oxide crystal structure following this interaction...
March 25, 2017: Materials
Jie Wang, Qinqin Ma, Xiao-Xiao Hu, Haoyang Liu, Wei Zheng, Xueyuan Chen, Quan Yuan, Weihong Tan
Optical bioimaging is an indispensable tool in modern biology and medicine, but the technique is susceptible to autofluorescence interference. Persistent nanophosphors provide an easy-to-perform and highly efficient means to eliminate tissue autofluorescence. However, direct synthesis of persistent nanophosphors with tunable properties to meet different bioimaging requirements remains largely unexplored. In this work, zinc gallogermanate (Zn1+xGa2-2xGexO4:Cr, 0 ≤ x ≤ 0.5, ZGGO:Cr) persistent luminescence nanoparticles with composition-dependent size and persistent luminescence are reported...
August 8, 2017: ACS Nano
Matthew F Paige, Ala'a F Eftaiha
The mutual immiscibility of hydrogenated and fluorinated surfactants at interfaces frequently leads to phase-separation, which provides a useful and flexible method for patterning air-water and solid-air interfaces. In this article, we review recent advances in the use of hydrogenated-fluorinated surfactant mixtures to achieve interfacial patterning. For even relatively simple systems comprised of binary mixed monolayers of hydrogenated and perfluorinated fatty acids, a diverse range of film morphologies can be generated at the air-water interface and successfully transferred onto solid substrates...
July 20, 2017: Advances in Colloid and Interface Science
Yuanyuan Wang, Igor Fedin, Hao Zhang, Dmitri V Talapin
Photolithography is an important manufacturing process that relies on using photoresists, typically polymer formulations, that change solubility when illuminated with ultraviolet light. Here, we introduce a general chemical approach for photoresist-free, direct optical lithography of functional inorganic nanomaterials. The patterned materials can be metals, semiconductors, oxides, magnetic, or rare earth compositions. No organic impurities are present in the patterned layers, which helps achieve good electronic and optical properties...
July 28, 2017: Science
Sidney E Creutz, Rachel Fainblat, Younghwan Kim, Michael C De Siena, Daniel R Gamelin
Doping lanthanide ions into colloidal semiconductor nanocrystals is a promising strategy for combining their sharp and efficient 4f-4f emission with the strong broadband absorption and low-phonon-energy crystalline environment of semiconductors to make new solution-processable spectral-conversion nanophosphors, but synthesis of this class of materials has proven extraordinarily challenging because of fundamental chemical incompatibilities between lanthanides and most intermediate-gap semiconductors. Here, we present a new strategy for accessing lanthanide-doped visible-light-absorbing semiconductor nanocrystals by demonstrating selective cation exchange to convert precursor Yb(3+)-doped NaInS2 nanocrystals into Yb(3+)-doped PbIn2S4 nanocrystals...
August 16, 2017: Journal of the American Chemical Society
Luís Pinto da Silva, Rui F J Pereira, Carla M Magalhães, Joaquim C G Esteves da Silva
The bioluminescent reaction of the "sea firefly" Cypridina hilgen-dorfii is a prototypical system for marine bioluminescence, as its substrate possesses an imidazopyrazinone core that is a common link among organisms of eight phyla. The elucidation of the mecha-nism behind Cypridina bioluminescence is essential for future applications in bioimaging, biomedicine and bioanalysis. In this study we have investigated the key step of chemiexcitation with a combined experimental and theoretical approach. The obtained results indicate that neutral dioxetanone is responsible for efficient chemiexcitation, as the thermolysis of this species gives access to a long region of the potential energy surface (PES), where the ground and excited singlet states are degenerated...
July 27, 2017: Journal of Physical Chemistry. B
Luuk Kortekaas, Federico Lancia, Jorn D Steen, Wesley R Browne
The coupling of substituted carbazole compounds through carbon-carbon bond formation upon one-electron oxidation is shown to be a highly versatile approach to the formation of redox polymer films. Although the polymerization of single carbazole units has been proposed earlier, we show that by tethering pairs of carbazoles double sequential dimerization allows for facile formation of redox polymer films with fine control over film thickness. We show that the design of the monomers and in particular the bridging units is key to polymer formation, with the diaminobenzene motif proving advantageous, in terms of the matching to the redox potentials of the monomer and polymer film and thereby avoiding limitations in film thickness (autoinsulation), but introduces unacceptable instability due to the intrinsic redox activity of this moiety...
July 13, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
B Santiago-Gonzalez, A Monguzzi, M Caputo, C Villa, M Prato, C Santambrogio, Y Torrente, F Meinardi, S Brovelli
Metal nanoclusters featuring tunable luminescence and high biocompatibility are receiving attention as fluorescent markers for cellular imaging. The recently discovered ability of gold clusters to scavenge cytotoxic reactive oxygen species (ROS) from the intracellular environment extends their applicability to biomedical theranostics and provides a novel platform for realizing multifunctional luminescent probes with engineered anti-cytotoxic activity for applications in bio-diagnostics and conceivably cellular therapy...
July 20, 2017: Scientific Reports
K R Krishnadas, Ananya Baksi, Atanu Ghosh, Ganapati Natarajan, Anirban Som, Thalappil Pradeep
Nanoparticles exhibit a rich variety in terms of structure, composition, and properties. However, reactions between them remain largely unexplored. In this Account, we discuss an emerging aspect of nanomaterials chemistry, namely, interparticle reactions in solution phase, similar to reactions between molecules, involving atomically precise noble metal clusters. A brief historical account of the developments, starting from the bare, gas phase clusters, which led to the synthesis of atomically precise monolayer protected clusters in solution, is presented first...
July 20, 2017: Accounts of Chemical Research
Pia Gruber, Marco P C Marques, Nicolas Szita, Torsten Mayr
The quantification of key variables such as oxygen, pH, carbon dioxide, glucose, and temperature provides essential information for biological and biotechnological applications and their development. Microfluidic devices offer an opportunity to accelerate research and development in these areas due to their small scale, and the fine control over the microenvironment, provided that these key variables can be measured. Optical sensors are well-suited for this task. They offer non-invasive and non-destructive monitoring of the mentioned variables, and the establishment of time-course profiles without the need for sampling from the microfluidic devices...
August 8, 2017: Lab on a Chip
Jyun-Liang Lin, James M Wagner, Hal S Alper
Within the Design-Build-Test Cycle for strain engineering, rapid product detection and selection strategies remain challenging and limit overall throughput. Here we summarize a wide variety of modalities that transduce chemical concentrations into easily measured absorbance, luminescence, and fluorescence signals. Specifically, we cover protein-based biosensors (including transcription factors), nucleic acid-based biosensors, coupled enzyme reactions, bioorthogonal chemistry, and fluorescent and chromogenic dyes and substrates as modalities for detection...
July 16, 2017: Biotechnology Advances
Min Zhao, An-Yi Chen, Dan Huang, Ya-Qin Chai, Ying Zhuo, Ruo Yuan
Cd-based semiconductor quantum dots (QDs) with size-tunable luminescence and high quantum yield have become the most promising electrochemiluminescence (ECL) emitters. However, their unavoidable biotoxicity limited their applications in bioassays. Here, the nontoxic and economical MoS2 QDs prepared by chemical exfoliation from the bulk MoS2 were first investigated as new ECL emitters, and then the possible luminescence mechanism of MoS2 QDs was studied using ECL-potential curves and differential pulse voltammetry (DPV) methods in detail...
July 27, 2017: Analytical Chemistry
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