Thermal Quenching Mechanism of Mn in NaSiF, NaKSiF, and KSiF Phosphors: Insights from the First-Principles Analysis.

This study aims to identify the key factors governing the thermal quenching of Mn ion luminescence in fluoride-based phosphor materials used as red emitters in modern-day phosphor-converted LED devices. Here, we employ first-principles calculations for Mn-doped NaSiF, NaKSiF, and KSiF hosts to explore how host properties and local coordination environments influence thermal quenching behavior. The ΔSCF method was used to model the geometric structures of the MnA (ground) and E, T (excited) states and the energies of the optical transitions between these states.

A Detailed Comparative Analysis of the Structural Stability and Electron-Phonon Properties of ZrO: Mechanisms of Water Adsorption on t-ZrO (101) and t-YSZ (101) Surfaces.

In this study, we considered the structural stability, electronic properties, and phonon dispersion of the cubic (c-ZrO), tetragonal (t-ZrO), and monoclinic (m-ZrO) phases of ZrO. We found that the monoclinic phase of zirconium dioxide is the most stable among the three phases in terms of total energy, lowest enthalpy, highest entropy, and other thermodynamic properties. The smallest negative modes were found for m-ZrO.