Optical Response, Lithium Doping, and Charge Transfer in Sn-Based 312 MAX Phases.

The optical response, lithium doping, and charge transfer in three Sn-based existing MSnC MAX phases with electron localization function (ELF) were investigated using density functional theory (DFT). Optical calculations show a slight optical anisotropy in the spectra of different optical parameters in some energy ranges of the incident photons. The peak height is mostly slightly higher for the polarization ⟨001⟩.

Transition Metal Layer Substitution in MoCS MXene for Improving Li Ion Surface Kinetics.

We study the adsorption and mobility of a Li ion on the surface of the MoCS MXene by means of Density Functional Theory. We find that by substituting the Mo atoms of the upper MXene layer with V the mobility of the Li ion can be improved up to 95% while the material retains its metallic character. This fact indicates that MoVCS is a promising candidate for anode electrode in Li-ion batteries, where the materials need to be conductive and the Li ion needs to have a small migration barrier.

Natural Time Analysis: The Area under the Receiver Operating Characteristic Curve of the Order Parameter Fluctuations Minima Preceding Major Earthquakes.

It has been reported that major earthquakes are preceded by Seismic Electric Signals (SES). Observations show that in the natural time analysis of an earthquake (EQ) catalog, an SES activity starts when the fluctuations of the order parameter of seismicity exhibit a minimum. Fifteen distinct minima-observed simultaneously at two different natural time scales and deeper than a certain threshold-are found on analyzing the seismicity of Japan from 1 January 1984 to 11 March 2011 (the time of the M9 Tohoku EQ occurrence) 1 to 3 months before large EQs.

Electronegativity and doping in SiGe alloys.

Silicon germanium alloys are technologically important in microelectronics but also they are an important paradigm and model system to study the intricacies of the defect processes on random alloys. The key in semiconductors is that dopants and defects can tune their electronic properties and although their impact is well established in elemental semiconductors such as silicon they are not well characterized in random semiconductor alloys such as silicon germanium. In particular the impact of electronegativity of the local environment on the electronic properties of the dopant atom needs to be clarified.

Impact of local composition on the energetics of E-centres in SiGe alloys.

The energetics of the defect chemistry and processes in semiconducting alloys is both technologically and theoretically significant. This is because defects in semiconductors are critical to tune their electronic properties. These processes are less well understood in random semiconductor alloys such as silicon germanium as compared to elementary semiconductors (for example silicon).

The CC(Si) Defect in Silicon from a Density Functional Theory Perspective.

Carbon constitutes a significant defect in silicon (Si) as it can interact with intrinsic point defects and affect the operation of devices. In heavily irradiated Si containing carbon the initially produced carbon interstitial-carbon substitutional (CC) defect can associate with self-interstitials (Si's) to form, in the course of irradiation, the CC(Si) defect and further form larger complexes namely, CC(Si) defects, by the sequential trapping of self-interstitials defects. In the present study, we use density functional theory to clarify the structure and energetics of the CC(Si) defects.

Hydrogen and nitrogen codoping of anatase TiO for efficiency enhancement in organic solar cells.

TiO has high chemical stability, strong catalytic activity and is an electron transport material in organic solar cells. However, the presence of trap states near the band edges of TiO arising from defects at grain boundaries significantly affects the efficiency of organic solar cells. To become an efficient electron transport material for organic photovoltaics and related devices, such as perovskite solar cells and photocatalytic devices, it is important to tailor its band edges via doping.