- 标题
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- 实验方案
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Cu2ZnGe(S1-xSe x)4 – The challenge to synthesize single phase material
摘要： The variation of the band gap energy in Cu2ZnGeSe4 and Cu2ZnGeS4 from 1.4 eV to 1.7 eV, which is controlled by different S/(S+Se) ratios renders the Cu2ZnGe(S1-xSex)4 solid solution an interesting material for the application in multi-junction solar cells. Nevertheless, this system has a certain complexity due to the existence of different polymorphs. Cu2ZnGeSe4 crystallizes in the tetragonal kesterite type structure, whereas Cu2ZnGeS4 may crystallize in the tetragonal stannite or the orthorhombic wurtz-stannite type structure, respectively. To gain deeper insights into this complex system a systematic study of the solid solution series Cu2ZnGe(S1-xSex)4 was performed using polycrystalline material prepared by solid state reaction. The chemical analysis performed by wavelength dispersive X-ray spectroscopy showed remarkable inhomogeneities with different quaternary phases co-existing within one sample. Additionally, a wide variety of binary and ternary secondary phases as well as elemental Ge was observed. The variety of secondary phases is higher in S-rich samples than in Se-rich samples of the solid solution. Thus, synthesis of Cu2ZnGe(S1-xSex)4 mixed crystals with off-stoichiometric composition is readily accompanied by the formation of various secondary phases making it a difficult task to obtain single phase material.
关键词： Wavelength dispersive X-ray spectroscopy,Solid state reaction,Polycrystalline powders,Chalcogenides,Secondary phases,Copper zinc germanium selenide,Copper zinc germanium sulfide
更新于2025-09-11 14:15:04
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Scaling up solid-state quantum photonics
摘要： A deterministic interface between a single atom and a single optical photon is the essential building block underpinning many quantum applications of light for quantum communication, sensing, and simulations. Light and matter interact weakly with each other, so the challenge is to create conditions enabling strong interactions. Fortunately, solid-state quantum photonics has matured dramatically, and it is possible to create artificial photonic nanostructures that markedly enhance light-matter coupling. Moreover, single atoms, which are cumbersome to control experimentally because they need to be trapped and cooled, can be replaced by solid-state quantum emitters such as vacancy centers in diamond, molecules, or quantum dots. The high quality and purity of these systems now imply that coherent and near-deterministic photon-emitter interfaces are routinely constructed, but it is still challenging to scale up and deterministically couple multiple quantum emitters. On page 662 of this issue, Evans et al. report on the successful coupling of two diamond silicon vacancy (SiV) quantum emitters mediated by their mutual coupling to a nanophotonic cavity. Radiative coupling leads to the formation of an entangled state between the two emitters.
关键词： diamond,entanglement,silicon vacancies,solid-state quantum photonics,quantum optics
更新于2025-09-11 14:15:04
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Understanding Solid-State Solvation-Enhanced Thermally Activated Delayed Fluorescence Using a Descriptor-Tuned Screened Range-Separated Functional
摘要： An efficient computational protocol suitable for both solutions and solid films can accelerate the development of efficient thermally activated delayed fluorescence (TADF) emitters aimed at practical application in organic light-emitting diodes (OLEDs). By employing the localized orbital locator (LOL), we establish an efficient descriptor-tuning methodology for the range-separated (RS) and screened range-separated (SRS) functionals with only one single-point calculation. This scheme provides good predictions for 28 charge transfer (CT)-type TADF emitters. Moreover, in comparison to the experimental data, the scheme presents a mean absolute deviation of 0.09 eV for the absorption energies of the lowest excited singlet state (EVA(S1)) in polarizable continuum model (PCM) solution and 0.10 eV for the energy difference between the lowest excited singlet and triplet states (ΔEST) under static solid-state polarization. Importantly, our results indicate that a significantly polarized S1 is key to realizing the so-called solid-state solvation-enhanced (SSSE)-TADF, which is well captured through the screened RS functionals combined with LOL-tuning (SLOL-tuning). Compared with standard ionization potential (IP)-tuning, our scheme significantly reduces the computational cost of the prediction of singlet- and triplet-transition energies for CT molecules. It also provides a reliable approach to evaluate the practical TADF character influenced by solid-state solvation in amorphous organic thin films.
关键词： Thermally Activated Delayed Fluorescence,Optical,Solid-State Solvation-Enhanced,Plasmonics,Magnetic,Hybrid Materials,TADF,Range-Separated Functional,LOL-tuning,OLEDs
更新于2025-09-11 14:15:04
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Scaling Phononic Quantum Networks of Solid-State Spins with Closed Mechanical Subsystems
摘要： Phononic quantum networks feature distinct advantages over photonic networks for on-chip quantum communications, providing a promising platform for developing quantum computers with robust solid-state spin qubits. Large mechanical networks including one-dimensional chains of trapped ions, however, have inherent and well-known scaling problems. In addition, chiral phononic processes, which are necessary for conventional phononic quantum networks, are difficult to implement in a solid-state system. To overcome these seemingly unsolvable obstacles, we have developed a new network architecture that breaks a large mechanical network into small and closed mechanical subsystems. This architecture is implemented in a diamond phononic nanostructure featuring alternating phononic crystal waveguides with specially designed band gaps. The implementation also includes nanomechanical resonators coupled to color centers through phonon-assisted transitions as well as quantum state transfer protocols that can be robust against the thermal environment.
关键词： quantum communications,diamond phononic nanostructure,Phononic quantum networks,quantum state transfer,solid-state spin qubits
更新于2025-09-10 09:29:36
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Inter-Diffusion of Iridium, Platinum, Palladium and Rhodium with Germanium
摘要： The down-scaling of nanoelectronic devices to ever smaller dimensions and greater performance has pushed silicon-based devices to their physical limits. Much effort is currently being invested in research to examine the feasibility of replacing Si by a higher mobility semiconductor, such as germanium, in niche high-performance metal oxide semiconductor (MOS) devices. Before Ge can be adopted in industry, a suitable contact material for the active areas of a transistor must be identified. It is proposed that platinum group metal (pgm) germanides be used for this purpose, in a similar manner as metal silicides are used in Si technology. Implementation of Ge-based technology requires a thorough understanding of the solid-state interactions in metal/Ge systems in order to foresee and avoid problems that may be encountered during integration. We present a systematic study of the solid-state interactions in germanide systems of four of the pgms: iridium, platinum, palladium and rhodium. Our approach was essentially twofold. Firstly, conventional thin film couples were used to study the sequence of phase formation in the germanide systems. Conventional thin film couples were also used to identify and monitor the dominant diffusing species during the formation of some of the germanides as these can influence the thermal stability of a device. Secondly, we observed and analysed several aspects of the lateral diffusion reactions in these four systems, including activation energies and diffusion mechanisms. Lateral diffusion couples were prepared by the deposition of thick rectangular islands of one material on to thin films of another material. Rutherford backscattering spectrometry (RBS) and microprobe-Rutherford backscattering spectrometry (μRBS) were used to analyse several aspects of the thin film and lateral diffusion interactions respectively. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were also employed.
关键词： nanoelectronic devices,solid-state interactions,germanium,platinum group metal germanides,lateral diffusion
更新于2025-09-10 09:29:36
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Solid-state synthesis and characterization of α-Fe2O3@ZnO nanocomposites with enhanced visible light driven photocatalytic activity
摘要： The α-Fe2O3@ZnOx (x = 25, 50 and 75 mol%) nanocomposites were synthesized by solid-state method. The formation of nanocomposites was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy and UV–Visible absorption spectroscopy. High purity of α-Fe2O3 and ZnO was observed in XRD patterns including lesser amount of ZnFe2O4. The growth of ZnO nanostructures on Fe2O3 rods was affirmed by scanning and transmission electron microscopy. Visible light driven photocatalytic degradation of roxarsone (ROX) was performed by using as-synthesized nanocomposites. The photocatalytic experiments were monitored by high pressure liquid chromatography. The α-Fe2O3@ZnO50% shows 89.7% of ROX degradation efficiency within 330 min and thus it exhibits best photocatalytic activity than the other composites. Moreover, the stability and possible photocatalytic pathway were also evaluated.
关键词： Solid-state synthesis,Nanocomposites,α-Fe2O3@ZnO,Photocatalytic activity,Roxarsone
更新于2025-09-10 09:29:36
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Higher permittivity of Ni-doped Lead Zirconate Titanate, Pb[(Zr0.52Ti0.48)(1-x) Nix]O3, ceramics
摘要： The paper reports highest obtained dielectric constant for Ni-doped Lead Zirconate Titanate [PZT, Pb(Zr0.52Ti0.48)O3] ceramics. The Ni-doped PZT ceramic pellets were prepared via conventional solid-state reaction method with Ni content chosen in the range 0-20 at.%. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were employed to investigate the crystal structure of the prepared ceramics. The X-ray diffraction analysis indicated that the ceramic pellets had crystallized into tetragonal perovskite structure. A minute displacement of XRD peaks was detected in the diffraction spectra of Ni-doped PZT which when examined by size-strain plot (SSP) method revealed presence of homogenous strain that decreased with increase in concentration of Ni. In FTIR the maximum absorption at 597 cm-1, 608 cm-1, 611 cm-1, 605 and 613 cm-1 for Ni = 0, 5, 10, 15 and 20 at.%, respectively, confirmed the formation of perovskite structure in all the compositions and the slight shift suggests decrease in cell size on doping. The values of dielectric constant (ε￠) & tand as a function of frequency and temperature were measured for the prepared ceramics and it revealed highest ever reported dielectric constant for Ni - doped PZT with Ni = 5 at.%. The dielectric variation with temperature exhibited a diffused type ferroelectric–paraelectric phase transition for the doped samples. Also, the maximum dielectric constant value (??max) decreased with an increase in doping concentration of Ni while the phase transition temperature increased with increase in doping concentration. The estimated activation energy of different compositions was found to increase from 0.057 to 0.068 eV for x = 0.00 to x = 0.20 in ferroelectric phase. The piezoelectric, ferroelectric and magnetic properties were also investigated.
关键词： Piezoelectric ceramics,Dielectric,solid-state reaction,Ni-doping
更新于2025-09-10 09:29:36
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Neutral heteroleptic cyclometallated Platinum(II) complexes featuring 2-phenylbenzimidazole ligand as bright emitters in solid state and in solution
摘要： A series of 8 neutral cyclometallated platinum(II) complexes featuring 2-phenylbenzimidazole chromophoric ligand and acetylacetonate as ancillary ligand has been synthesized and characterized. The introduction of a variety of substituent on the phenyl ring allows to finely tune the emission wavelength. The emission data reveal high quantum yield in deaerated solution and in bulk solid state (micro-crystalline powder), with values up to an impressive 51%. The emission for all of the complexes is attributed to a mixed 3LC-MLCT state. Both absorption and emission data have been correlated successfully with the redox potentials and the Hammett parameters.
关键词： photophysics,phosphorescence,platinum,organometallic,solid state emission
更新于2025-09-10 09:29:36
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Synthesis and multimethodological characterization of neodymium substituted nickel tungstates and molybdates solid solution Ni Ndx (W,Mo)O4, (0?≤?x?≤?0.2)
摘要： New series of neodymium substituted nickel tungstates and molybdates NiNdxM’O4 (M’=W,Mo and x=0%, 10%, 20%) were synthesized by standard solid state route at high temperature T=1000°C.These materials, were characterized by powder X-Ray diffraction technique (XRD), which confirmed that both series of tungstates and molybdates crystallized in monoclinic structure with space groups(P2/c, C2/m) respectively and behaved as a quasi-ideal solid solution. Scanning Electron Microscopy (SEM) experiments showed the presence of grains with irregular sizes developed within larger aggregations, while EDS semi-quantitative analyses confirmed the nominal compositions for all the phases.Active vibration modes were investigated by Fourier Transform InfraRed (FTIR) and Raman techniques, the group theoretical calculation predicted 36 vibrational modes. The presence of characteristic frequencies assigned to components ?1 and ?3 confirmed the existence of WO6 and MoO6 polyhedra in the structures, non-vibrational bands appearing in Raman spectra were attributed to laser-excited luminescence of neodymium element.
关键词： solid state reaction,vibrational properties,neodymium,nickel tungstates,X-ray diffraction,nickel molybdates
更新于2025-09-10 09:29:36
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Metal ion sensing ability and photo-physical properties of 4-hydroxy-3-nitroso-2H-chromen-2-one: Interaction studies with calf thymus-DNA
摘要： 4-Hydroxy-3-nitroso-2H-chromen-2-one (HNC), a coumarin derivative has been synthesized through a very simple method, and its photo-physical properties were studied. HNC is used as a simple colorimetric as well as spectrophotometric chemosensor for the detection of Fe2+, Co2+, Ni2+ and Cu2+ ions, some even by naked-eyes. This process gives a sensitive readout of chemosensor HNC within a wide range of (4.5–1219.5) × 10?7 (M) at λmax 258 nm. HNC has greater binding and detection ability toward Fe2+ than that of 1,10-phenanthrolin, and it has greater binding ability for Fe2+ than that with Fe3+ also. We have also established a method for solid state sensing of iron salts by HNC. Moreover, the binding interaction of HNC with calf-thymus DNA (CT-DNA) established a groove binding mode.
关键词： CT-DNA,Coumarin,Solid state Fe2+ ion sensing,Naked-eye metal sensing,Chemosensor
更新于2025-09-10 09:29:36