Kinetic analysis on the nanocrystal solid-solution formation was performed by heat treating CdSe/ZnSe core/shell nanocrystals, synthesized via a typical TOP/TOPO approach, at different temperatures for different time periods. X-ray diffraction (XRD) peak shifts in Cd1-xZnxSe cores according to the solid-solution treatments were monitored and used for the estimation of the lattice parameter change. The degree of solid-solution formation was determined considering the compositional variation in Cd1-xZnxSe cores, which was obtained from the Vegard's law. The degree of solid-solution formation (x) was applied to Jander analysis, and an Arrhenius-type plot was produced using the slopes of Jander plots. The activation energy for solid-solution formation was determined as approximately 152 kJ/mol, which evidently indicates that the diffusion of Zn2+ ions in the CdSe-ZnSe system is the governing mechanism for the Cd1-xZnxSe solid-solution formation. The Jander equation to predict the solid-solution formation kinetics for the CdSe/ZnSe core/shell systems was completed using the reaction rate constant (k).
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Chemphyschem
January 2025
Dalhousie University, Department of Chemistry, 6274 Coburg Road, P.O. box 15000, B3H4R2, Halifax, CANADA.
High entropy alloy (HEA) nanoparticles (NPs) have attracted much attention recently due to their unprecedented chemical properties. As such, HEA NPs have been used as materials with superior activity toward electrocatalytic applications. Specifically, solid solutions that form randomly mixed single-phased structures have received the most focus in the early stages of HEA NP development for their entropic-driven design and multifunctionality.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300300, China.
To enhance the tribological properties of the coatings and to inhibit cracking, sandwich-structured composite coatings were fabricated, consisting of a Ni60CuMo/IN718 transition layer and a Ni60CuMo/Ni-coated Cu wear-resistant layer with four different Ni-coated Cu contents. The results indicate that the transition layer inhibits the crack formation in the coating, and the refined grain structure stabilizes its average hardness at approximately 485 HV. Increasing the Cu content in the wear-resistant layer exacerbates the segregation of the Cu-rich solid solution phases and refines the in situ-generated CrC, TiC, and NbC phases.
View Article and Find Full Text PDFSmall
January 2025
Department of Materials Science and Engineering, National Yang-Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
Silver chalcogenides exhibit exceptional transport properties but face structural instability at high temperatures, limiting their practical applications. Using AgTe as a model, it is confirm that silver whisker growth above the phase transition renders AgTe unsuitable for thermoelectric applications. Here, the whisker growth mechanism is investigated and propose an inhibition strategy, overcoming a major obstacle in using silver chalcogenides.
View Article and Find Full Text PDFAdv Mater
January 2025
Materials Science and Engineering Program, Walker Department of Mechanical Engineering and Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
Anode-free all solid-state batteries (AF-ASSBs) employ "empty" current collector with three active interfaces that determine electrochemical stability; lithium metal - Solid electrolyte (SE) interphase (SEI-1), lithium - current collector interface, and collector - SE interphase (SEI-2). Argyrodite LiPSCl (LPSCl) solid electrolyte (SE) displays SEI-2 containing copper sulfides, formed even at open circuit. Bilayer of 140 nm magnesium/30 nm tungsten (Mg/W-Cu) controls the three interfaces and allows for state-of-the-art electrochemical performance in half-cells and fullcells.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
As a leading candidate for high-voltage, cobalt-free cathodes, spinel LiNiMnO (LNMO) oxide is highly attractive for next-generation lithium-ion batteries. However, the instability of cation-oxygen bonds (especially Mn-O) and the adverse two-phase transition of LNMO result in rapid crystal collapse during cycling, thus limiting its practical deployment. To address these issues, herein we exploit the differences in miscibility between dopants and the spinel matrix to embed high-entropy doped microregions (HEDRs, 5-15 nm in size) within the spinel.
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