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91.
92.
Dr. Matthias Daxner Prof. Stephan Denifl Prof. Paul Scheier Prof. Andrew M. Ellis 《Angewandte Chemie (International ed. in English)》2014,53(49):13528-13531
The self‐assembly of salt nanocrystals from chemical reactions inside liquid helium is reported for the first time. Reaction is initiated by an electron impacting a helium nanodroplet containing sodium atoms and SF6 molecules, leading to preferential production of energetically favorable structures based on the unit cell of crystalline NaF. These favorable structures are observed as magic number ions (anomalously intense peaks) in mass spectra and are seen in both cationic and anionic channels in mass spectra, for example, (NaF)nNa+ and (NaF)nF?. In the case of anions the self‐assembly is not directly initiated by electrons: the dominant process involves resonant electron‐induced production of metastable electronically excited He? anions, which then initiate anionic chemistry by electron transfer. 相似文献
93.
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/chitin nanocrystals (CNC) composite scaffolds were synthesized by the salt leaching and thermally induced phase separation (TIPS) technique. The scaffolds have porous structures with macro-pores (100-300 mm in diameters) and micro-pores (10 mm). The surface characteristics of the scaffolds were characterized by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurement, and the mechanical properties were investigated by a compression test. Human adipose-derived stem cells (hADSCs) were seeded onto the PHBV/CNC scaffolds and in vitro cell culture results showed that the composite scaffolds enhanced the hADSCs adhesion, which implies that the material may have potential application in tissue engineering. 相似文献
94.
Ying Liu Dr. Ximing Rong Mingze Li Prof. Maxim S. Molokeev Prof. Jing Zhao Prof. Zhiguo Xia 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(28):11731-11737
The incorporation of impurity ions or doping is a promising method for controlling the electronic and optical properties and the structural stability of halide perovskite nanocrystals (NCs). Herein, we establish relationships between rare-earth ions doping and intrinsic emission of lead-free double perovskite Cs2AgInCl6 NCs to impart and tune the optical performances in the visible light region. Tb3+ ions were incorporated into Cs2AgInCl6 NCs and occupied In3+ sites as verified by both crystallographic analyses and first-principles calculations. Trace amounts of Bi doping endowed the characteristic emission (5D4→7F6-3) of Tb3+ ions with a new excitation peak at 368 nm rather than the single characteristic excitation at 290 nm of Tb3+. By controlling Tb3+ ions concentration, the emission colors of Bi-doped Cs2Ag(In1−xTbx)Cl6 NCs could be continuously tuned from green to orange, through the efficient energy-transfer channel from self-trapped excitons to Tb3+ ions. Our study provides the salient features of the material design of lead-free perovskite NCs and to expand their luminescence applications. 相似文献
95.
Vasyl Hreb Vira Shved Oleh Buryy Olga Pekinchak Leonid Vasylechko 《无机化学与普通化学杂志》2020,646(14):1138-1143
Crystal structure parameters of the mixed cobaltite–chromite SmCo0.5Cr0.5O3 in the temperature range of 298–1173 K were derived from in situ high-resolution X-ray synchrotron powder diffraction data. Similar to the parent SmCoO3 compound, SmCo0.5Cr0.5O3 reveals anomalous thermal expansion reflected in abnormal temperature dependence of the unit cell dimensions and the selected interatomic distances and angles. These anomalies are associated with temperature induced changes of spin state of Co3+ ions and coupled insulator-metal transition. Observed decreasing behavior of the bandwidth W points on the increasing population of the exited spin states of Co3+ ions in SmCo0.5Cr0.5O3 with increasing temperature. First principle calculations revealed antiferromagnetic ground state of SmCo0.5Cr0.5O3 as the most stable. 相似文献
96.
A new controlled aging methodology was developed for the synthesis of PbS colloidal quantum dots (QDs), applying larger PbS QDs as a starting material for smaller QDs by application of environmentally friendly oleic acid and oleylamine as reagents. This simple and mild procedure provides a possible strategy for tailoring the size-dependent properties of PbS QDs. 相似文献
97.
The excellent properties of Methyl Ammonium Lead Iodide (MAPI) have already created an extensive research interest in photovoltaic applications. However, their utility in thermoelectric application is still not realized thoroughly by researchers. By continuing this interest, we have explored the formation of low dimensional CH3NH3PbI3 (MAPI) perovskite in presence of Polyaniline (PANI) and Multi-Walled Carbon Nanotubes (MWCNT) and its thermoelectric performance. For this purpose, a two stage, in-situ synthesis method was developed to prepare various composites such as MAPI-PANI, MWCNT-MAPI and MWCNT-PANI-MAPI. The as-formed MWCNT-PANI-MAPI composite revealed p-type conductivity with enhanced ZT (up to ~20,000 times) and power factor (3000 times) at room temperature as compared to pristine MAPI sample. Finally, we have demonstrated a proto-type thermoelectric power generator (TE device) fabricated using the best performing composite sample and measured its power output and efficiency at varied δT. 相似文献
98.
In this work, a novel electrochemiluminescent (ECL) pesticide sensor based on zinc oxide nanocrystals decorated nickel foam is proposed for determination of imidacloprid for the first time. The silica film was used as a morphology‐controlling factor for modification of the electrode with zinc oxide nanocrystals. Zinc oxide was selected as luminescent material due to its cheapness, non‐toxicity, high thermal stability and excellent luminescence properties which truly adhered on the surface of nickel foam. The K2S2O8 was used as strong co‐reactant for this purpose. The silica template plays an important role in controlling the size of ZnO nanocrystals. The Physical morphology of the ZnO/Ni‐foam electrode was performed by electrochemical impedance spectroscopy, Brunauer‐Emmett‐Teller (BET), X‐Ray diffraction analysis, field emission scanning electron microscopy, and energy‐dispersive X‐ray analysis. The ultra‐sensitive electrochemiluminescence method was successfully used for ultra‐trace determination of imidacloprid. The linear dynamic range and low detection limit were obtained 3×10?14 ?8×10?8 M and 4.4×10?15 M, respectively. Also, the relative standard deviation for 15 repetitive optical signals was calculated 1.09 %.The present ECL sensor exhibited superior performance toward the accurate determination of imidacloprid with good reproducibility and stability. 相似文献
99.
High dielectric constant is highly desirable in capacitors and memory devices. In this work, oleic acid (OA)‐capped BaTiO3 nanocrystals were synthesized by a two‐phase approach. Polyimide (PI)/BaTiO3‐nanocrystal composite thin films with high dielectric constant have been successfully fabricated. The morphologies and dielectric properties of the hybrid films were exploited. The results showed that BaTiO3 nanocrystals can be uniformly dispersed in the PI thin films owing to the surface modification of OA‐capped BaTiO3 nanocrystals. It was found that the dielectric constant of composite film varies with the volume fraction of BaTiO3 nanocrystals and sintering temperatures and reaches a maximum value of 44.1, which is around 13 times higher than that of pristine PI thin film (3.2). These results demonstrated that PI/BaTiO3‐nanocrystal composite films have considerable application potential in microelectronic fields. 相似文献
100.
Shuo Tao Xiaolei Li Xiaoge Wang Ying Wei Yunling Jia Jing Ju Yuanhui Cheng Huaisheng Wang Shuwen Gong Xingjun Yao Haixu Gao Cunyin Zhang Qiqi Zang Zhijian Tian 《Angewandte Chemie (International ed. in English)》2020,59(9):3455-3459
The synthesis of hierarchical nanosized zeolite materials without growth modifiers and mesoporogens remains a substantial challenge. Herein, we report a general synthetic approach to produce hierarchical nanosized single‐crystal aluminophosphate molecular sieves by preparing highly homogeneous and concentrated precursors and heating at elevated temperatures. Accordingly, aluminophosphate zeotypes of LTA (8‐rings), AEL (10‐rings), AFI (12‐rings), and ‐CLO (20‐rings) topologies, ranging from small to extra‐large pores, were synthesized. These materials show exceptional properties, including small crystallites (30–150 nm), good monodispersity, abundant mesopores, and excellent thermal stability. A time‐dependent study revealed a non‐classical crystallization pathway by particle attachment. This work opens a new avenue for the development of hierarchical nanosized zeolite materials and understanding their crystallization mechanism. 相似文献