Tunable electronic structure and excellent catalytic properties of transition-metal-doped BeN monolayer.

The electronic properties and OER catalytic activity of pristine BeN monolayers and single-transition-metal-doped BeN monolayers (TM@BeN) were systematically investigated using density functional theory. Among all the types of TM@BeN analyzed, Fe@BeN was determined to exhibit the best OER activity, with an overpotential of 0.33 V, and to display excellent metallic conductivity.

Ultra-high photoelectric conversion efficiency and obvious carrier separation in photovoltaic ZnInX (X = S, Se, and Te) van der Waals heterostructures.

The need for low-carbon solar electricity production has become increasingly urgent for energy security and climate change mitigation. However, the bandgap and carrier separation critical requirements of high-efficiency solar cells are difficult to satisfy simultaneously in a single material. In this work, several van der Waals ZnInX (X = S, Se, and Te) heterostructures were designed based on density functional theory.

Enhanced OER catalytic activity of single metal atoms supported by the pentagonal NiN monolayer: insight from density functional theory calculations.

Two-dimensional material-supported single metal atom catalysts have been extensively studied and proved effective in electrocatalytic reactions in recent years. In this work, we systematically investigate the OER catalytic properties of single metal atoms supported by the NiN monolayer. Several typical transition metals with high single atom catalytic activity, such as Fe, Co, Ru, Rh, Pd, Ir, and Pt, were selected as catalytic active sites.

Enhanced optical absorption in two-dimensional Ruddlesden-Popper (CHCHNH)PbI perovskites biaxial strain and surface doping.

Two-dimensional Ruddlesden-Popper (2D RP) perovskites can form layered protective materials using long organic cations as "barrier" caps, which is expected to solve the problem of instability of perovskites in the working environment. In this work, we systematically studied the 2D Ruddlesden-Popper (CHCHNH)PbI hybrid perovskites using density functional theory. The results reveal that the 2D (CHCHNH)PbI perovskites are semiconductors with band gaps of 2.

P-block atom modified Sn(200) surface as a promising electrocatalyst for two-electron CO reduction: a first-principles study.

Low activity and poor product selectivity of CO reduction have seriously hampered its further practical application. Introducing p-block atoms to the catalyst is regarded as a promising strategy due to the versatility of p orbitals and diversity of p-block elements. Here, we systematically studied the influence of p-block atom X (X = C, N, O, S, and Se) on CO catalytic properties on a Sn(200) surface by first-principles calculation.

The unique photoelectronic properties of the two-dimensional Janus MoSSe/WSSe superlattice: a first-principles study.

Designing photocatalysts with suitable band alignment and considerable carrier mobility is extremely important. Here, by means of first-principles calculation, we systematically investigated the structural, photoelectronic, and carrier mobility behavior of the two-dimensional Janus MoSSe/WSSe superlattice. The results show that both armchair-type (A-SL) and zigzag-type (Z-SL) superlattices are relatively stable with negative values in the range of -2.

The oxygen vacancy in Li-ion battery cathode materials.

The substantial capacity gap between available anode and cathode materials for commercial Li-ion batteries (LiBs) remains, as of today, an unsolved problem. Oxygen vacancies (OVs) can promote Li-ion diffusion, reduce the charge transfer resistance, and improve the capacity and rate performance of LiBs. However, OVs can also lead to accelerated degradation of the cathode material structure, and from there, of the battery performance.

Injection of oxygen vacancies in the bulk lattice of layered cathodes.

Surfaces, interfaces and grain boundaries are classically known to be sinks of defects generated within the bulk lattice. Here, we report an inverse case by which the defects generated at the particle surface are continuously pumped into the bulk lattice. We show that, during operation of a rechargeable battery, oxygen vacancies produced at the surfaces of lithium-rich layered cathode particles migrate towards the inside lattice.

Enhanced optical absorption via cation doping hybrid lead iodine perovskites.

The suitable band structure is vital for perovskite solar cells, which greatly affect the high photoelectric conversion efficiency. Cation substitution is an effective approach to tune the electric structure, carrier concentration, and optical absorption of hybrid lead iodine perovskites. In this work, the electronic structures and optical properties of cation (Bi, Sn, and TI) doped tetragonal formamidinium lead iodine CH(NH)PbI (FAPbI) are studied by first-principles calculations.

Tuning band gaps and optical absorption of BiOCl through doping and strain: insight form DFT calculations.

Bismuth oxyhalides (BiOX, X = Cl, Br, and I) are a new family of promising photocatalysts. BiOCl and BiOBr possess large band gaps and weak absorption in visible light regions, which limit their applications. Although the band gap of BiOI is suitable to absorb most of the visible light, its redox capability is very weak.

Effect of water on the effective Goldschmidt tolerance factor and photoelectric conversion efficiency of organic-inorganic perovskite: insights from first-principles calculations.

Water is often believed to be the leading killer of perovskite solar cells' efficiency. However, recent experimental results show that perovskite solar cells have higher photoelectric conversion efficiency in a suitably moist environment. In this study, the relationship between the interstitial water molecule and the theoretical maximum efficiency of the perovskite absorber layer is discussed based on density functional theory calculations.

First-Principles Study of Novel Two-Dimensional (CHNH)PbX Perovskites for Solar Cell Absorbers.

Low-dimensional perovskites (ABX), in which the A cations are replaced by different organic cations, may be used for photovoltaic applications. In this contribution, we systematically study the two-dimensional (2D) (CHNH)PbX (X═Cl, Br and I) hybrid perovskites by density functional theory (DFT). A clear structures-properties relationship, with the photophysical characteristics directly related to the dimensionality and material compositions, was established.

Unusual Li-Ion Transfer Mechanism in Liquid Electrolytes: A First-Principles Study.

Liquid electrolytes play an important role in commercial lithium-ion (Li-ion) batteries as a conduit for Li-ion transfer between anodes and cathodes. It is generally believed that the Li-ions move along with the salt ions; thus, Li-ion diffusion is only affected by the viscosity and salt concentration in the liquid electrolytes based on the Stokes-Einstein equation. In this study, a novel and faster Li-ion diffusion mechanism in electrolytes containing a cyanogen group is identified from first-principles molecular dynamics (FPMD) simulations.

Spatial separation of photo-generated electron-hole pairs in BiOBr/BiOI bilayer to facilitate water splitting.

The electronic structures and photocatalytic properties of bismuth oxyhalide bilayers (BiOX1/BiOX2, X1 and X2 are Cl, Br, I) are studied by density functional theory. Briefly, their compositionally tunable bandgaps range from 1.85 to 3.

Electronic and magnetism properties of two-dimensional stacked nickel hydroxides and nitrides.

Two-dimensional (2D) layered materials receive a lot of attention because of their outstanding intrinsic properties and wide applications. In this work, the structural, electronic and magnetic properties of nickel hydroxides (Ni(OH)2) and nitrides XN (X = B, Al, and Ga) heterostructures are studied by first-principles calculations. The results show that the pristine monolayer Ni(OH)2 owns no macro magnetism with antiferromagnetic (AFM) coupling between two nearest Ni atoms, the electronic structure can be modulated through the heterostructures.

The stability and electronic properties of novel three-dimensional graphene-MoS2 hybrid structure.

Three-dimensional (3D) hybrid layered materials receive a lot of attention because of their outstanding intrinsic properties and wide applications. In this work, the stability and electronic structure of three-dimensional graphene-MoS2 (3 DGM) hybrid structures are examined based on first-principle calculations. The results reveal that the 3 DGMs can easily self-assembled by graphene nanosheet and zigzag MoS2 nanoribbons, and they are thermodynamically stable at room temperature.