- 标题
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- 实验方案
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Ultraviolet electroluminescence from nanostructural SnO2-based heterojunction with high-pressure synthesized Li-doped ZnO as a hole source
摘要： We report an ultraviolet (UV) electroluminescence (EL) in n-SnO2/p-ZnO heterojunction light-emitting diodes with the nanostructural SnO2 as an n-type layer and the Li-doped ZnO (ZnO:Li) synthesized by high-temperature high-pressure (HTHP) method as a high hole concentration p-type layer. Two kinds of SnO2 nanostructures including nanobelts (NBs) and nanowires (NWs) were used to fabricate n-type layers in the heterojunctions. The two heterojunctions with different SnO2 nanostructures demonstrate different light-emission feature in EL measurements. The SnO2 NBs/p-ZnO heterojunction shows a blue emission band centered at 416 nm under forward-bias voltage. A strong UV emission peak located at 391 nm was observed for the SnO2 NWs/p-ZnO heterojunction. Photoluminescence (PL) spectra indicate that the difference in EL is attributed to morphology-dependent light-emission feature in nanostructural SnO2 layer. Our results suggest that the nanostructural SnO2/ZnO:Li heterojunction is a potential and promising system in the UV optoelectronic field.
关键词： High-temperature high-pressure method,Light-emitting diode,Nanobelt,Nanowire,SnO2,Li-doped ZnO
更新于2025-09-23 15:22:29
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[Methods in Molecular Biology] Autophagy Volume 1880 (Methods and Protocols) || Correlative Light and Electron Microscopy to Analyze LC3 Proteins in Caenorhabditis elegans Embryo
摘要： In this chapter, we present a protocol to perform correlative light and electron microscopy (CLEM) on Caenorhabditis elegans embryos. We use a specific fixation method which preserves both the GFP fluorescence and the structural integrity of the samples. Thin sections are first analyzed by light microscopy to detect GFP-tagged proteins, then by transmission electron microscopy (TEM) to characterize the ultrastructural anatomy of cells. The superimposition of light and electron images allows to determine the subcellular localization of the fluorescent protein. We have used this method to characterize the roles of autophagy in the phagocytosis of apoptotic cells in C. elegans embryos. We analyzed in apoptotic cell and phagocytic cell the localization of the two homologs of LC3/GABARAP proteins, namely, LGG-1 and LGG-2.
关键词： LC3-associated phagocytosis,High-pressure freezing,Freeze substitution,LGG-2,Green fluorescent protein,GMA resin,LGG-1
更新于2025-09-23 15:22:29
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Rivalry Under Pressure - The Coexistence of Ambient-pressure Motifs and Close-packing in Silicon Phosphorus Nitride Imide SiP2N4NH
摘要： Non-metal nitrides such as BN, Si3N4 and P3N5 meet numerous demands on high-performance materials and their high-pressure polymorphs exhibit outstanding mechanical properties. Herein, we present the silicon phosphorus nitride imide SiP2N4NH featuring six-fold coordinated Si. Using the multianvil technique, SiP2N4NH was obtained from high-pressure high-temperature synthesis at 8 GPa and 1100 °C with in situ formed HCl acting as a mineralizer. Its structure was elucidated by combination of single-crystal X-ray diffraction and solid-state NMR measurements. Moreover, SiP2N4NH was characterized by energy-dispersive X-ray spectroscopy and (temperature-dependent) powder X-ray diffraction. The highly condensed Si/P/N framework features PN4 tetrahedra as well as the rare motif of SiN6 octahedra and is discussed in the context of ambient-pressure motifs competing with close-packing of nitride anions, representing a missing link in high-pressure chemistry of non-metal nitrides.
关键词： nitrides,silicon,high-pressure chemistry,phosphorus,solid-state structures
更新于2025-09-23 15:22:29
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Simple imaging for the diamond anvil cell: Applications to hard-to-reach places
摘要： The employment of high-pressure gases as a pressure-transmitting medium, sample, or reactant for diamond anvil cell experiments is widespread. As a pressure transmitter, high-pressure gases are crucial to forming quasi-hydrostatic compression atmospheres for samples inside the uniaxially driven cell. We describe an optical design for forming high-resolution images of the gasket and sample chamber of the diamond anvil cell under high gas pressures in a gas loading apparatus. Our design is simple, is of low-cost, and may be easily adapted to suit gas loading apparatus of any design, as well as other common hard-to-reach environments in diamond anvil cell experiments, i.e., those with large stand-off distances, such as cryostats.
关键词： optical design,high-pressure gases,gas loading apparatus,diamond anvil cell,imaging
更新于2025-09-23 15:21:21
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In situ high-pressure spectroscopic studies using moissanite (4H-SiC) anvils
摘要： We examined the Raman scattering and IR absorption spectroscopy of 4H-SiC and its performance as an anvil material for high-pressure UV-visible absorption spectroscopic measurements. The first- and second-order Raman peaks of 4H-SiC and diamond do not coincide. 4H-SiC does not have obvious signals from 2330-5000 cm-1, suggesting that 4H-SiC anvils are beneficial for high-pressure studies of samples whose Raman signals locate in the region of diamond. Above 1800 cm-1, the transmitted signal of 4H-SiC in the IR absorption spectra, measured through 4.6 mm thickness is much higher than that of type IIa diamond. An in situ high-pressure UV-visible absorption spectroscopy study on CdI2 was carried out up to 28.0 GPa using 4H-SiC anvil cells (4H-SAC) with a 400 μm culet and the acquired band gap narrowed with increasing pressure. These results show that 4H-SiC has an excellent performance in high-pressure spectroscopic studies.
关键词： IR absorption spectroscopy,high-pressure,UV-visible absorption spectroscopy,Raman spectroscopy,4H-SiC
更新于2025-09-23 15:21:21
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Persistence of the R3m Phase in Powder GeTe at High Pressure and High Temperature
摘要： As a phase-change material, rhombohedral GeTe (space group R3m) was believed to transform to the cubic rock-salt phase (B1) at 3–4 GPa, associated with the disappearance of a Peierls distortion. However, using a combination of synchrotron X-ray diffraction and theoretical calculations, we found that the R3m phase persists from ambient pressure up to pressures of about 15.8 GPa, in contrast to previous reports. Neither was the B1 phase observed in a heating X-ray powder diffraction experiment. The spurious transformation from R3m to B1 is caused by changes to the compression ratio of lattice parameters in the R3m phase under high pressure/temperature. These findings provide insight into transitions of phase-change materials, relevant to other materials undergoing displacive transitions under high pressure/temperature.
关键词： structural phase transitions,density-functional theory,high pressure,phase-change materials,high temperature,GeTe,synchrotron X-ray diffraction
更新于2025-09-23 15:21:01
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Plasmonic Sensing of Refractive Index and Density in Methanol-Ethanol Mixtures at High Pressure
摘要： The localized surface plasmon resonance (LSPR) of gold nanospheres dispersed in methanol-ethanol 4:1 was measured as a function of pressure up to 60 GPa. The LSPR exhibits an intense redshift with pressure in the range of 0-10 GPa, followed by a slower blueshift at higher pressures. This is because an increase in the solvent refractive index with pressure leads to a redshift of the LSPR peak wavelength while an increase in the electron density of the gold nanospheres with pressure leads to a blueshift. Solvent solidification at 10 GPa and associated non-hydrostatic effects have a negligible influence on the LSPR shifts in the case of nanospheres. Here we show that both the LSPR shifts and changes in the nanospheres absorption coefficient can be explained on the basis of Gans’ model, and this enables the solvent refractive index and the density of the solvent to be determined across the hydrostatic pressure range from 0-60 GPa. Interestingly, plasmonic sensing shows no evidence of crystallization or glass phase transitions in MeOH-EtOH (4:1) solvents within the explored pressure range.
关键词： High Pressure,Optical,Hybrid Materials,Methanol-Ethanol Mixtures,Density,Plasmonics,Magnetic,Refractive Index
更新于2025-09-23 15:21:01
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Raman high-pressure study of butane isomers up to 40 GPa
摘要： Raman spectroscopy studies on n and i-butane were performed at pressures of up to 40 GPa at ambient temperatures using the DAC technique. Normal butane undergoes two phase transitions at 1.9(5) GPa and 2.9(5) GPa and isobutane at 2.7(5) GPa and 3.5(5) GPa. These phase transitions were identi?ed based on observations of the splitting Raman modes and the appearance or disappearance of particular Raman peaks. Our results demonstrate the complex, high-pressure behavior of butane isomers.
关键词： Raman spectroscopy,high-pressure,DAC technique,phase transitions,butane isomers
更新于2025-09-23 15:21:01
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High-Pressure Electronic Structure and Optical Properties of N-Doped ZnO
摘要： The electronic structures and optical properties of N-doped ZnO under high pressure have been investigated using first-principles methods. The pressure effects on the lattice parameters, electronic band structures, and partial density of states (PDOS) of crystalline N-doped ZnO are calculated up to 8 GPa. The lattice parameters a, and c are decreases by 0.062 and 0.091 ?, respectively. Moreover, the evolution of the dielectric function, absorption coefficient (α(ω)), reflectivity (R(ω)), and the real part of the refractive index (n(ω)) at high pressure are also presented.
关键词： N-doped ZnO,density functional theory,optical properties,high pressure
更新于2025-09-23 15:21:01
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Lithium Pentazolate Synthesized by Laser Heating Compressed Lithium Azide and Nitrogen
摘要： Searching for polynitrogen compounds has attracted great attention due to their potential applications as high energy density materials. Here, we report a facile approach to the synthesis of solid lithium pentazolate (LiN5) compound by compressing lithium azide and molecular nitrogen under high pressure with laser heating. The formation of LiN5 with crystal structure P21/m-LiN5 was identified according to the appearance of the vibrational modes of N5ˉ rings in Raman spectra and synchrotron X-ray diffraction measurements under high pressure. The LiN5 remains stable down to 18.5 GPa upon decompression. The bond lengths in N5ˉ are between single bond and double bond length. This study indicates that the precursor can effectively tune the high pressure phase of pentazolate providing us an alternative route to synthesize polynitrogen compound with novel structure.
关键词： Lithium azide,Laser heating,High pressure,Nitrogen and Lithium pentazolate
更新于2025-09-23 15:21:01