Infrared surface plasmon and hot carrier properties of topological nodal line semimetal ZrSiS.

Recently, a new plasmon mode, the nodal-line plasmon, was discovered in ZrSiS, which provides promising possibilities for plasmonics or optics. However, there remains a lack of research on the surface plasmon (SP) properties and carrier transport characteristics of ZrSiS. In this paper, we conduct an in-depth study of these properties and compare them with the traditional SP material Au.

A calculation method for optical properties of yolk shell based on deep learning.

The yolk shell is widely used in optoelectronic devices due to its excellent optical properties. Compared to single metal nanostructures, yolk shells have more controllable degrees of freedom, which may make experiments and simulations more complex. Using neural networks can efficiently simplify the computational process of yolk shell.

The anisotropic broadband surface plasmon polariton and hot carrier properties of borophene monolayer.

Borophene monolayer with its intrinsic metallic and anisotropic band structures exhibits extraordinary electronic, optical, and transport properties. Especially, the high density of Dirac electrons enables promising applications for building low-loss broadband SPP devices. However, a systematic characterization of the surface plasmon polariton (SPP) properties and hot carriers generated from the inevitable SPP decay in borophene has not been reported so far.

Efficient N- and O-Sensing Properties of PtSe With Proper Intrinsic Defects.

Developing efficient N and O gas sensors is of great importance to our daily life and industrial technology. In this work, first-principles calculations are performed to study the N and O gas-sensing properties of pure and defected PtSe. It is found that both N and O adsorb weakly on pure PtSe, and adsorption of the molecules induces negligible changes in the electrical and optical properties.

Cu-Ag alloy for engineering properties and applications based on the LSPR of metal nanoparticles.

Efficient generation of high-energy hot carriers from the localized surface plasmon resonance (LSPR) of noble metal (Ag, Au and Cu) nanoparticles is fundamental to many applications based on LSPR, such as photovoltaics and photocatalysis. Theoretically, intra- and inter-band electron transitions in metal nanoparticles are two important channels for the non-radiative decay of LSPR, which determine the generation rate and energy of hot carriers. Therefore, on the basis of first-principles calculations and Drude theory, in this work we explore the potential role of alloying Ag with Cu in modulating the generation rate and energy of hot carriers by studying the intra- and inter-band electron transitions in Cu, Ag and Cu-Ag alloys.

Geometric and electronic properties of ultrathin anatase TiO(001) films.

Ultrathin anatase TiO(001) films have recently been shown to exhibit many exotic properties, which are not observed in their thick counterpart. In this work, the dependence of the geometric and electronic properties of ultrathin anatase TiO(001) films on the number of O-Ti-O trilayers is investigated on the basis of first-principles calculations. It is interesting to find that the lattice parameters, intertrilayer distances, electronic band gap and the position of the valence band edge for the films depend strongly on the number of trilayers, and they exhibit pronounced odd-even oscillations with the number of trilayers.

Schottky barrier and band edge engineering via the interfacial structure and strain for the Pt/TiO heterostructure.

Charge transfer across the Pt/TiO interface, which is mainly determined by the interface Schottky barrier height (SBH), is an important process in the (photo)catalytic and electronic applications of the Pt/TiO composite. Therefore, systematic investigation of the factors that affect the interface SBH is indispensable for understanding and optimizing its performance. In this work, a systematic study of the effects of the interfacial structure and strain on the SBH of the Pt/TiO(001) interface has been carried out based on the first-principles calculations.

Oxygen vacancies at the Au/SrTiO(001) interface: stabilities, electronic properties and effect on photocatalysis.

Oxygen vacancies have proven to induce various and important effects on the properties of materials. In the present work, the thermodynamic stabilities and electronic properties of oxygen vacancies (Ov) on the SrTiO (STO)(001) surface and at the Au/STO(001) interface are systematically investigated by means of first-principles calculations. Both the SrO and TiO terminated (001) surfaces of STO are examined.

Giant spin-orbit coupling topological insulator h-GaBi with exotic O-bridge states.

The two-dimensional (2D) topological insulator (TI) is a promising material for designing dissipationless spintronic devices. Although many candidates have been found, few of them have a massive spin-orbit coupling (SOC) strength with high stability. In the present work, we demonstrate that h-GaBi is a highly stable 2D TI with a massive E(Γ) at the Γ point of 1.

Electron-Rotor Interaction in Organic-Inorganic Lead Iodide Perovskites Discovered by Isotope Effects.

We report on the carrier-rotor coupling effect in perovskite organic-inorganic hybrid lead iodide (CH3NH3PbI3) compounds discovered by isotope effects. Deuterated organic-inorganic perovskite compounds including CH3ND3PbI3, CD3NH3PbI3, and CD3ND3PbI3 were synthesized. Devices made from regular CH3NH3PbI3 and deuterated CH3ND3PbI3 exhibit comparable performance in band gap, current-voltage, carrier mobility, and power conversion efficiency.

Hydrogen Doped Metal Oxide Semiconductors with Exceptional and Tunable Localized Surface Plasmon Resonances.

Heavily doped semiconductors have recently emerged as a remarkable class of plasmonic alternative to conventional noble metals; however, controlled manipulation of their surface plasmon bands toward short wavelengths, especially in the visible light spectrum, still remains a challenge. Here we demonstrate that hydrogen doped given MoO3 and WO3 via a facile H-spillover approach, namely, hydrogen bronzes, exhibit strong localized surface plasmon resonances in the visible light region. Through variation of their stoichiometric compositions, tunable plasmon resonances could be observed in a wide range, which hinge upon the reduction temperatures, metal species, the nature and the size of metal oxide supports in the synthetic H2 reduction process as well as oxidation treatment in the postsynthetic process.

Energy transfer in plasmonic photocatalytic composites.

Among the many novel photocatalytic systems developed in very recent years, plasmonic photocatalytic composites possess great potential for use in applications and are one of the most intensively investigated photocatalytic systems owing to their high solar energy utilization efficiency. In these composites, the plasmonic nanoparticles (PNPs) efficiently absorb solar light through localized surface plasmon resonance and convert it into energetic electrons and holes in the nearby semiconductor. This energy transfer from PNPs to semiconductors plays a decisive role in the overall photocatalytic performance.

Interface Schottky barrier engineering via strain in metal-semiconductor composites.

The interfacial carrier transfer property, which is dominated by the interface Schottky barrier height (SBH), plays a crucial role in determining the performance of metal-semiconductor heterostructures in a variety of applications. Therefore, artificially controlling the interface SBH is of great importance for their industrial applications. As a model system, the Au/TiO2 (001) heterostructure is studied using first-principles calculations and the tight-binding method in the present study.

The synergistic effect between effective mass and built-in electric field for the transfer of carriers in nonlinear optical materials.

Recent experiments have demonstrated that the typical nonlinear optical material K3B6O10Br can be an excellent photocatalyst under ultraviolet (UV) light irradiation. To understand the origin of the photocatalytic activity and further improve its photocatalytic efficiency to develop alternative photocatalysts, the built-in electric field and the electron effective mass and their synergistic effect on transfer and the separation of carriers in K3B6O10X (X = Br, Cl) were investigated by means of first-principles calculations. Our results show that the built-in electric field and the smallest effective mass of holes in K3B6O10Br are both along the [001] direction.

Origin of the increased photocatalytic performance of TiO₂ nanocrystal composed of pure core and heavily nitrogen-doped shell: a theoretical study.

We have carried out a theoretical study to explain the photocatalytic performance of the newly synthesized special core (pure TiO2)-shell (heavily nitrogen (N)-doped TiO2) structure of TiO2 nanocrystal using advanced first-principles calculations. The conventional N doping models by maximizing the mutual distances between dopants are found to only introduce localized gap states irrespective of doping concentrations, which is in agreement with previous theoretical results but cannot explain the experimental results. In comparison, the electronically coupled N doping of TiO2, which is almost as stable as the conventional doping models and generally overlooked in previous works, can not only narrow the overall band gap but also decrease the carrier recombination rate.

Near-infrared photocatalytic activity induced by intrinsic defects in Bi2MO6 (M = W, Mo).

The electronic structure and related photocatalytic properties of Bi2MO6 (M = W, Mo) with various intrinsic defects are studied based on the first-principles density functional theory (DFT). Our results indicate that O vacancies form easily in both Bi2WO6 and Bi2MoO6 under Bi rich/O poor conditions. The near-infrared light transitions can be realized involving electrons from the O vacancy induced impurity states within the band gap to the conduction band.

New basic insights into the low hot electron injection efficiency of gold-nanoparticle-photosensitized titanium dioxide.

The low hot electrons injection efficiency (HEIE) from plasmonic metal to semiconductor significantly affects the performance of metal-semiconductor composite. However, there are few reports about the origin of this low HEIE. In the present work, the factors affecting the transfer process and generation efficiency of hot electron in Au@TiO2 composite are investigated using first-principles calculations and Maxwell's electrodynamics theory.

Noble-metal-free plasmonic photocatalyst: hydrogen doped semiconductors.

The unique capacity of localized surface plasmon resonance (LSPR) offers a new opportunity to overcome the limited efficiency of semiconductor photocatalyst. Here we unravel that LSPR, which usually occurs in noble metal nanoparticles, can be realized by hydrogen doping in noble-metal-free semiconductor using TiO2 as a model photocatalyst. Moreover, its LSPR is located in infrared region, which supplements that of noble metal whose LSPR is generally in the visible region, making it possible to extend the light response of photocatalyst to infrared region.

Relative photooxidation and photoreduction activities of the {100}, {101}, and {001} surfaces of anatase TiO2.

The photoredox ability of the TiO2 {100}, {101}, and {001} surfaces is investigated by examining the trapping energies, trapping sites, and relative oxidation and reduction potentials of simulated photogenerated holes and electrons in the form of more realistic polaronic states on the basis of density functional electronic structure calculations. Our results enable us to re-estimate their relative photooxidation ({100} > {101} > {001}) and photoreduction ({100} > {101} > {001}) activities, which rectify the conventional understanding. The dual functions of the surface under coordinated atoms acting as active adsorption sites for adsorbates and hindering the population of electrons to the outermost surface layer are identified, and the specific surface geometric structures also play an important role in trapping holes and electrons through the ease of lattice distortion.