The Interplay of Interstitial and Substitutional Copper in Zinc Oxide.

Cu impurities are reported to have significant effects on the electrical and optical properties of bulk ZnO. In this work, we study the defect properties of Cu in ZnO using hybrid quantum mechanical/molecular mechanical (QM/MM)-embedded cluster calculations based on a multi-region approach that allows us to model defects at the true dilute limit, with polarization effects described in an accurate and consistent manner. We compute the electronic structure, energetics, and geometries of Cu impurities, including substitutional and interstitial configurations, and analyze their effects on the electronic structure.

High Anisotropic Optoelectronics in Two Dimensional Layered PbSnX (X = S/Se).

We systematically study the giant anisotropic optoelectronics in layered PbSnX (X = S/Se). The highly anisotropic optoelectronics mainly originates from the asymmetric sublattices SnX, resulting in the anisotropy of photoelectronic properties with fascinating visible light absorption range in single-layer and bilayer PbSnX. We employ uniaxial strain in both the and directions and find an indirect-to-direct band gap transition, while the quasiparticle indirect band gap presents excellent linear scaling with biaxial strain in monolayer PbSnX.

Stability and Catalytic Performance of Single-Atom Supported on Ti CO for Low-Temperature CO Oxidation: A First-Principles Study.

Based on first-principles calculations, the potential of Ti CO monolayer (MXene) as a single-atom catalyst (SAC) support for 3d transition metal (TM) atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) is studied for CO oxidation. We first screen the support effect according to the stability of a single metal atom and find that Sc and Ti supported on Ti CO have stronger adsorption energy than the cohesive energy of their bulk counterparts and therefore, we selected Sc and Ti supported on Ti CO for further catalytic reactions. The stability and the potential catalytic reactivity are verified by electronic structure and charge transfer analysis.

Identification of electronic descriptors for catalytic activity of transition-metal and non-metal doped MoS.

While the d-band theory offers successful electronic descriptors for catalytic activity of transition metals, transition metal compounds still need substantial theoretical input for the identification of reactivity descriptors for fast screening of earth-abundant catalysts. We study transition metal (TM) and non-metal doped MoS2, a promising substitute for noble metals as catalysts for multiple reactions, to clarify how doping modifies the reactivity by regulating the electronic structure of the host. We find that doping can significantly change the density of states (DOS) at band edges and the position of the Fermi level, which renders the S p-band center εp a good descriptor for H adsorption on both TM and non-metal doped MoS2.

UV-vis spectroscopic studies of low-energy argon-ion-bombarded ion-exchanged glasses.

The ion-exchanged glasses bombarded with 80 eV, 100 eV, and 120 eV argon ions at room temperature are investigated. The optical and structural properties of ion-exchanged glasses before and after bombardment were analyzed by means of a UV-vis spectrometer, x-ray photoelectron spectroscopy, and electron probe micro analysis, respectively. The optical absorption and transmittance spectra of ion-exchanged glasses appear as obvious changes in the UV-visible region after bombardment.