Synthesis, structure, and luminescence characteristics of far-red emitting Mn4+-activated LaScO3 perovskite phosphors for plant growth

Ab Initio Study of the Mechanism of Proton Migration in Perovskite LaScO3

The mechanism of proton motion in a LaScO3 perovskite crystal was studied by ab initio molecular dynamics. The calculations were performed at different temperatures, locations, and initial velocity of the proton. Different magnitudes and directions of the external electric field were also considered. It is shown that initial location and interaction between proton and its nearest environment are of great importance to the character of the proton movement, while the magnitude and direction of the initial velocity and electric field strength are secondary factors characterizing its movement through the LaScO3 crystal. Four types of proton-jumping between oxygen atoms are determined and the probability of each of them is established. Energy barriers and characteristic times of these jumps are determined. The probable distances from a proton to other types of atoms present in perovskite are calculated. It is shown that the temperature determines, to a greater extent, the nature of the motion of a proton in a perovskite crystal than the magnitude of the external electric field. The distortion of the crystal lattice and its polarization provoke the formation of a potential well, which determines the path for the proton to move and its mobility in the perovskite crystal.

Structure and luminescence behaviour of a novel red-emitting fluoroperovskite for display backlight application

In this work, we present a brand-new narrowband red-emitting fluoroperovskite via the introduction of Mn⁴⁺ into NaZnF₃ through a facile co-precipitation method at room temperature. The physicochemical properties of the fluoroperovskite such as crystal and electronic structures, morphology, and elemental composition, as well as its spectroscopic properties such as luminescence behaviours and optical performance were characterized and investigated in detail. Evidence shows that NaZnF₃:Mn⁴⁺ exhibits a uniform particulate shape with single-phase crystallinity. By virtue of the non-equivalent substitution and the [MnF₆] octahedral distortion in the fluoride host, sharp red emissions of phonon sidebands and the zero-phonon line upon blue light excitation are identified. Benefiting from the unique spectral feature, a wide colour gamut of 104.1% NTSC is achieved by coating β-SiAlON:Eu²⁺ and NaZnF₃:Mn⁴⁺ on an InGaN chip, indicating the potential use of the Mn⁴⁺ fluoroperovskite as a colour converter for display backlight application.