A novel 1D/1D nanocomposite-based photodetector is successfully fabricated from high-crystalline ZnS/ZnO biaxial nanobelts for the first time. Optimized performance of nanobelt much better than that pure ZnS or ZnO nanostructures, with a wide-range UV-A light photoresponse, high sensitivity, and very fast response speed.

We developed a postgrowth modification method of two-dimensional WO3 nanoflakes by simultaneous solution etching and reducing process in weakly acidic condition. The obtained dual etched reduced have much rougher surface, which oxygen vacancies are created during the etching/reducing for optimized photoelectrochemical performance. photoanodes show an enhanced photocurrent density ∼1.10 mA/cm2 at 1.0 V vs Ag/AgCl (∼1.23 reversible hydrogen electrode), compared to 0.62 pristine nanoflakes....

We have investigated the thermal conductivity of graphene nanoribbons (GNRs) with different edge shapes as a function length, width, and strain using nonequilibrium molecular dynamics method. The initial GNR for functional variations has dimensions 2×11 nm2. Strong length dependence is obtained, indicating high conductivities GNRs, which consistent experimental results graphene. A tensile/compressive uniaxial can remarkably decrease GNR.

The magnetic energy levels of a given solid are closely packed in because the interactions between ions weak. Thus, describing its properties, one needs to generate spectrum by employing an appropriate spin Hamiltonian. In this review article we discuss how determine and specify necessary Hamiltonian terms first principles electronic structure calculations on basis energy-mapping analysis briefly survey important concepts phenomena that encounters reading current literature solids. Our...

A novel general method of describing the spin-lattice interactions in magnetic solids was proposed terms first principles calculations. The spin exchange and Dzyaloshinskii-Moriya as well their derivatives with respect to atomic displacements can be evaluated efficiently on basis density functional calculations for four ordered states. By taking into consideration spin-spin interactions, phonons, coupling between them, we show that ground state structure a representative spin-frustrated...

CsSnI3 is a prototype inorganic halide perovskite that has recently been proposed as strong candidate for photovoltaic applications because of its unique semiconductor properties. Through first-principle calculations, we show the concentration control intrinsic defects critical optimizing properties CsSnI3. Under Sn-poor condition, high acceptor defects, such Sn or Cs vacancies, can form easily and produce p-type conductivity deep-level become electron–hole recombination centers, all with...

We adopt a global optimization method to predict two-dimensional (2D) nanostructures through the particle-swarm (PSO) algorithm. By performing PSO simulations, we new stable structures of 2D boron-carbon (B-C) compounds for wide range boron concentrations. Our calculations show that: (1) All B-C are metallic except BC(3) which is magic case where isolation carbon six-membered ring by atoms results in semi-conducting behavior. (2) For C-rich compounds, most can be viewed as doped graphene...

Crystal structure prediction is a long-standing challenge in condensed matter and chemical science. Here we report machine-learning approach for crystal prediction, which graph network (GN) employed to establish correlation model between the formation enthalpies at given database, an optimization algorithm (OA) used accelerate search with lowest enthalpy. The framework of utilized (a database + GN algorithm) flexible. We implemented two benchmark databases, i.e., open quantum materials...

Using an all-electron band structure approach, we have systematically calculated the natural offsets between all group IV, III-V, and II-VI semiconductor compounds, taking into account deformation potential of core states. This revised approach removes assumptions regarding reference level volume offers a more reliable prediction “natural” unstrained offsets. Comparison is made to experimental work, where noticeable improvement found compared previous methodologies.

Due to its large band gap (3.2 eV), TiO2 cannot absorb sun light effectively. To reduce gap, various approaches have been attempted; most of them are using doping modify structure. Using first-principles structure calculations, we show that unlike the rutile phases, in anatase phase can be effectively reduced by applying stress along a soft direction. We propose this approach tuning direction layered semiconductor is general and should applicable other anisotropic materials.

Cubic ZnSe nanowires with periodically alternating twins along the wire growth direction (see Figure) have been synthesized using thermal evaporation a Au catalyst. The periodicity of has linear dependence on diameter nanowires. Sharp excitonic peaks dominating low-temperature photoluminescence spectrum reveal high quality their electronic structure despite large unpassivated surface and interface associated twinned nanowire configuration.

Diamond silicon (Si) is the leading material in current solar cell market. However, diamond Si an indirect band gap semiconductor with a large energy difference (2.3 eV) between direct and gap, which makes it inefficient absorber of light. In this work, we develop novel inverse structure design approach based on particle swarming optimization algorithm to predict metastable phases better optical properties than Si. Using our new method, cubic Si(20) phase quasidirect gaps 1.55 eV, promising...

We developed a postgrowth doping method of TiO2 nanowire arrays by simultaneous hydrothermal etching and in weakly alkaline condition. The obtained tungsten-doped core-shell nanowires have an amorphous shell with rough surface, which W species are incorporated into the during this etching/regrowth step for optimization photoelectrochemical performance. Photoanodes made these W-doped show much enhanced photocurrent density ~1.53 mA/cm(2) at 0.23 V vs Ag/AgCl (1.23 reversible hydrogen...

Two-dimensional (2D) semiconductors can be very useful for novel electronic and optoelectronic applications because of their good material properties. However, all current 2D materials have shortcomings that limit performance. As a result, new are highly desirable. Using atomic transmutation differential evolution global optimization methods, we identified two group IV–VI materials, Pma2-SiS silicene sulfide. is found to both chemically, energetically, thermally stable. Most importantly, has...

We calculate systematically the absolute volume deformation potential (AVDP) of ${\ensuremath{\Gamma}}_{8v}$ valence band maximum (VBM) and ${\ensuremath{\Gamma}}_{6c}$ conduction minimum (CBM) states for all group IV, III-V, II-VI semiconductors. Unlike previous calculations that involve various assumptions, AVDPs are calculated using a recently developed approach is independent selection reference energy levels. find although potentials CBM state usually large always negative, those VBM...

The unusual nonlinear behaviors of the band gaps in ${\text{Sn}}_{x}{\text{Ge}}_{1\ensuremath{-}x}$ alloys are investigated using first-principles calculations. We show that large bowing direct gap is induced by disordering effect. Moreover, we calculated individual contribution band-edge states and found conduction edge much larger than valence edge, although natural valence-band offset between Ge Sn conduction-band offset. breakdown distribution rule explained lattice mismatch deformation...

Grain boundaries in as-grown polycrystalline MoS2 monolayers are revealed by second-harmonic-generation microscopy. Through the anisotropic polarization pattern and phase interference at grain boundary, edge termination boundary types identified. Statistical analysis on hundreds of grains shows that grain-boundary formation is driven kinetics can be nicely described attachment growth model.

We report a nitrogen-doped carbon nanodot (N-Cdot)/TiO2 nanowire photoanode for solar-driven, real-time, and sensitive photoelectrochemical probing of the cellular generation H2S, an important endogenous gasotransmitter based on tunable interfacial charge carrier transfer mechanism. Synthesized by microwave-assisted solvothermal method subsequent surface chemical conjugation, obtained N-Cdot/TiO2 shows much enhanced photocurrent compared with pristine TiO2 nanowires. This increase is...

By performing density functional calculations, we investigate the origin of skyrmion state and ferroelectricity in Cu2OSeO3. We find that Dzyaloshinskii-Moriya interactions between two different kinds Cu ions are extremely strong induce helical ground absence presence magnetic field, respectively. On basis general model for spin-order induced polarization, propose ferroelectric polarization Cu2OSeO3 collinear ferrimagnetic arises from an unusual mechanism, i.e., single-spin-site contribution...

The ferroelectric polarization of triangular-lattice antiferromagnets induced by helical spin-spiral order is not explained any existing model magnetic-order-driven ferroelectricity. We resolve this problem developing a general theory for the and then evaluating coefficients needed to specify on basis density functional calculations. Our correctly describes ferroelectricity driven incorporates known models as special cases.

By extending our general spin-current model to non-centrosymmetric spin dimers and performing density functional calculations, we investigate the causes for helical magnetic order origin of giant ferroelectric polarization CaMn7O12. The is proposed be caused by symmetric exchange striction due canting Mn4+ arising from its strong Dzyaloshinskii-Moriya (DM) interaction. Our study suggests that CaMn7O12 may exhibit a novel magnetoelectric coupling mechanism in which magnitude governed...

Despite the recent progress of developing graphitic carbon nitride (g-C3N4) as a metal-free photocatalyst, synthesis nanostructured g-C3N4 has still remained complicated and time-consuming approach from its bulk powder, which substantially limits photoelectrochemical (PEC) applications well potential to form composites with other semiconductors. Different labor-intensive methods used before, such exfoliation or assistant templates, herein, we developed facile method synthesize C3N4 quantum...

By combining the electron–phonon coupling effect and static formalism, we calculate, through first-principles methods, carrier capture cross sections of three possible nonradiative recombination center (NRRC) defects in Cu2ZnSnS4. These values are currently unavailable but critical for understanding limiting factors minority lifetime simulating photovoltaic devices. We show that SnZn2+ capturing one electron (a (+2/+1) transition) [CuZn–SnZn]+ (+1/0) both very large, whereas SnZn+ is much...