A SnSe monolayer with an orthorhombic <italic>Pnma</italic> GeS structure is important two-dimensional (2D) indirect band gap material at room temperature.

The structural, electronic, and elastic properties of cubic HC(NH2)2PbI3 perovskite are investigated by density functional theory using the Tkatchenko–Scheffler pairwise dispersion scheme. Our relaxed lattice parameters in agreement with experimental data. hydrogen bonding between NH2 I ions is found to have a crucial role FAPbI3 stability. first calculated band structure shows that has direct bandgap (1.02 eV) at R-point, lower than (1.53 CH3NH3PbI3. states reveals strong hybridization...

The structural, elastic, electronic, and thermodynamic properties of thermoelectric material MgAgSb in γ,β,α phases are studied with first-principles calculations based on density functional theory. optimized lattice constants accord well the experimental data. According to calculated total energy three phases, phase transition order is determined from α γ cooling, which agreement result. physical such as elastic constants, bulk modulus, shear Young's Poisson's ratio, anisotropy factor also...

By using the first-principles calculations, band gap properties of nanotubes formed by group IV elements have been investigated systemically. Our results reveal that for armchair nanotubes, energy gaps at K points in Brillouin zone decrease as 1/r scaling law with radii (r) increasing, while they are scaled -1/r 2 + C Γ points, here, is a constant. Further studies show such independent both chiral vector and type elements. Therefore, given radius can be determined these laws easily....

A novel silicon-based micron/nanometer structural composite system, silicon nanoporous pillar array(Si-NPA), was prepared on the substrate of single-crystal si licon (sc-Si) wafers by a hydrothermal etching method; and studies its mo rphological optical properties were carried out. Structural exper iments disclose that Si-NPA could be well described triple hierarchical struc tures: array composed micron-sized pillars, nanopores densely distributing each pillar, nanocrystallites constructing...

The electrochemical activity and stability of the PBCO electrode are investigated under annealing processes in an atmosphere containing CO2/H2O for solid oxide fuel cells (SOFCs). impedance spectrum results unequivocally confirm significant deterioration cathode performance upon ambient air conditions, particularly when exposed to atmospheres. Microstructure surface chemical state analyses reveal segregation BaO on surface, formation insulating BaCO3 degraded performance. CO2 H2O exhibit a...

Abstract The extraordinary transmission properties of terahertz waves through arrays subwavelength holes on a metal film have been investigated. effects the geometrical parameters and dielectrics filling hole explored. results show that resonance peak shifts to long wavelength as width lattice period constant increase. As refractive index dielectric materials increases, transmittance increases changes low frequency. phase retardation can be flexibly changed by varying in hole. Keywords:...

The silicon nanoporous pillar array (Si-NPA) is synthesized by using hydrothermal etching method, and the electron field emission properties are studied. results show that Si-NPA has a low turn-on of 1.48 V/μm at current 0.1 μA its relatively stable. enhancement believed to originate from unique morphology structure. Our finding demonstrates promising candidate material for applications.

Nanocrystallites Au particles are deposited on a well-aligned silicon nanoporous pillar array (Si-NPA) surface through immersion plating to form an Au/Si-NPA composite system. It is found that large number of nanoparticles accumulated the bottom Si pillars regular network structure. By studying field emission properties such system, we find exhibits good properties, with staring about 2 V/μm and current density 67 μA/cm2 at 7.59 V/μm. The enhanced can be deduced from unique morphology...

We study the evolution phenomena of metal twist grain boundaries (GBs) in [100], [111] and [110] orientations, together with their bimetal interface, under anticlockwise clockwise torsions.

Under the framework of Maxwell–Garnett (M-G) model, optical and electrical properties single-walled carbon naotube (SWCNT), double-walled nanotube (DWCNT) hydrogen-doped (H-doped CNT) in terahertz (THz) region have been investigated. It has found that as frequency increases loss tangent conductivity show a peak. The SWCNT is larger than DWCNT H-doped CNT. increase with filling factor decreases geometrical factor.

By using the first-principles calculations based on density functional theory combined with quasi-harmonic approximation, we have studied geometric structural, thermal properties, and negative expansion (NTE) properties of tetrahedral NbPO5. The variations cell parameter volume NbPO5 temperature show that it displays NTE behavior in range 473-800 K along a-axis corresponding average coefficient (CTE) is approximately -0.766 ×10−6 K−1, while c display positive behaviors. These results are...

Abstract The inorganic perovskite CsPbCl 3 has raised great concern in recent years due to its tunability of luminescence properties via impurity doping. However, the blue-emitting mechanism impurity-doped is unexplored. In this work, we focus on structural, electronic, and optical CsPb 1- x TM Cl (TM=Mg, Cu; = 0, 0.037, 0.074) based first-principles calculations. It indicated that doping decreases lattice parameter, deforms octahedral structure, improves stability . increased direct bandgap...

Using first-principle calculations within density functional theory, we investigate the electronic property and stability of substitutionally doped 2D GeP3 monolayer with dopants from group III to VI. The conducting properties are found be dramatically modified by both doping sites number valence electrons dopants. Specifically, substitution on Ge site exhibits metal-semiconductor oscillations as a function dopants, while such totally reversed when P site. Moreover, also study case co-doping...

The friction can be affected dramatically by quantum size effects (QSEs) and edge at nanoscale. modulations of QSEs on nanofriction a rare gas (RG) monolayer sliding Pb(111) ultrathin films were investigated using the first-principles approach within density functional theory (DFT) with van der Waals (vdW) interaction correction. Our findings revealed that there exist even-odd oscillations in thickness substrate tuned up to 30% different thicknesses films. Moreover, such modulation is more...

Ag/ZnO photocatalysts with different silver content (0, 1, 2, and 3 mol%) were fabricated through a hydrothermal method. Characterization results of XRD showed the ZnO was hexagonal wurtzite structure, Ag face-centered cubic (fcc) structure. The morphologies suggested that particles nonuniform shapes (nano-rods, nano-spheres, nano-sheets). UV-Vis DRS absorbance spectra unveiled decrease in band gap for introduction Ag, indicating improvement visible light absorption. All samples demonstrated...

Employing silicon nanoporous pillar array (Si-NPA), a novel micron/nanometer complex systems as reducing substrate, self-supported, nanostructured gold film was prepared by immersion technique. The microstructure and surface morphology of the were characterized. Our experiments disclosed that preparation is self-stop process. With exhaustion Si-NPA, chemical reaction related with Au3+ ions occurring in immersing solution would stop automatically, deposited disengage from substrate to form...