Solid State Phenomena Vol. 365

Abstract: First-principles calculations are used within the framework of density functional theory to investigate the electronic, structural, magnetic and optical properties of Potassium Nitride (KN) in the bulk and monolayer states. This compound is dynamically stable according to phonon calculations. The results show that the energy gap decreases from the bulk to the monolayer. The equilibrium lattice constant increases when changing from bulk to monolayer, and the half-metallic (HM) character remains preserved in that case. According to the Slater–Pauling statute (Zt-4), the total magnetic moment equals 2 µ_B per unit cell. The electric field and biaxial strain affect the monolayer's electronic and magnetic characteristics were investigated. The magnitude of the spin-up channel concerning the energy gap changes under the biaxial strain. In particular, it decreases under tensile strain and increases under compression strain. Given that the values of magnetic moments remain unchanged, the HM property can be preserved for significant strains. When the electric field reaches -0.6 V/nm, the half-metallic property of this compound will be destroyed. It affects the energy gap and eliminates the HM trait since the magnetic moment of the K grew significantly greater than the moment of the N, and the N played a significant role in the realization of the half-metallic characteristic.

Abstract: Recently, all inorganic perovskite solar cells have triggered great attention thanks to the rising performance during their development in solid state photovoltaics showing enhanced characteristics, such as: good stability, high photoluminescence quantum yield, tunable size, and morphology. In this work, a high open-circuit voltage solar cell based on all-inorganic perovskite through SCAPS simulator program is presented by analysing electron transport layer (ETL), perovskite layer, hole transport layer (HTL) thickness and doping density from a FTO/TiO₂/CsPbBr₃/Spiro-OMeTAD/Au structure were modified to observe its influence on solar cell performance. Therefore, simulation results show that a thicker ETL hinders carrier transport towards the FTO layer due to larger distance which leads to higher recombination rate, reducing carrier’s lifetime. Albeit high doping density values in ETL enhances the overall solar cell performance. As for the absorber layer, while its thickness increases, carrier collection rate decreases due to recombination impacting Voc, which results from thickness increase. Based on the results, solar cell efficiency improvement is attributed to the built-in electric field as absorber layer doping density increases. While HTL thickness has minimum impact on the solar cell output, doping density enhances device parameters significantly. Summarising the results obtained from thickness and doping density simulations, the optimal solar cell operation was obtained at 10 nm, 600 nm, and 100 nm layer thickness as well as 10²⁰ cm^-3, 10¹⁶ cm^-3, and 10²⁰ cm^-3 doping density (TiO₂, CsPbBr₃ and Spiro-OMeTAD). Results from three different sources, collected from literature, were used to compare, and fitting them along with simulation results.

Abstract: Even though the descriptive definition of orientation is the same in both settings, the explicitnotation of a crystallographic orientation as (3 3) matrix in terms of Euler angles featuredby the popular MATLAB toolbox MTEX differs by an inversion from the quasi-standard notation datedback to the early days of quantitative texture analysis championed by H.-J. Bunge. The origin of thisdiscrepancy is revealed by an enlightening view provided in algebraic terms of a change of basis.Understanding the effect of inversion is instrumental to do proper computations with crystallographicorientations and rotations, e.g. when multiplying with elements of a crystallographic symmetry group,and to compare results of texture analyses accomplished in different settings.