Fabrication of Highly Efficient Pervoskite Solar Cells Using Simple Single-step Solution Method

This article presents optical property, crystal structure, and photovoltaic performance of perovskite solar cell (PSC) in n-i-p structure using simple single-step solution method with anti-solvent drip. The fabricated PSC exhibited a relatively high photovoltaic performance with the best power conversion efficiency of 15.8% under forward bias scan. The relatively high photovoltaic performance was probably resulted from the high crystallization, the high absorption coefficient, and the crack-like void-free on the surface of the perovskite absorbers.

Nanostructural theory of metal melts. Foundry production and metallurgy

It has been shown that atomic and atomic cluster theories cannot be the basis for theories of crystallization and modification of metals and alloys. Based on thermodynamic calculations, a nanostructural theory of metal melts has been developed. In this theory, the main structural elements are not atoms, but nanocrystals. They are thermodynamically stable in the metal melt, so they determine its structure and properties. Crystallization centers consist of nanocrystals. The intensity of aggregation of nanocrystals is determined by the concentration of demodifying surface-active elements. The action of modifiers is explained by the process of linking these elements. Nanostructural theory of metal melts explains the mechanism of action of modifying non-metallic inclusions and intermetallics, the effect of re-modification, high crystallization rate with high cooling intensity of the metal melt. Nanostructural theory of metal melts is the basis for theories of crystallization and modification of metals and alloys.

A Novel Bioactive Glass Containing Therapeutic Ions with Enhanced Biocompatibility

A novel bioactive glass containing therapeutic ions with enhanced biocompatibility was designed and produced by the classical melt-quenching route. Starting from a very promising composition (Bio_MS), which combined bioactivity and high crystallization temperature, the ratio between some oxides was tailored to obtain a new and more reactive (in terms of dissolution rate) bioactive glass, called BGMSN (composition in mol%: 6.1 Na2O, 31.3 CaO, 5 MgO, 10 SrO, 2.6 P2O5, 45 SiO2). The aim of this work was to produce a bioactive glass with a good biological performance, preserving, at the same time, the high crystallization temperature achieved for Bio_MS; this is strategic in order to avoid undesired crystalline phases during thermal treatments, which can undermine the bioactivity and even the stability of final products. A complete characterization of the novel bioactive glass was performed in terms of thermal, mechanical and biological properties and in vitro bioactivity. The thermal behavior of the bioactive glass was studied by heating microscopy, differential thermal analysis (DTA) and optical dilatometry; BGMSN showed a very high crystallization temperature and a high sinterability parameter, thus being suitable for applications where thermal treatments are required, such as sintered samples, coatings and scaffolds. Mechanical properties were investigated by the micro-indentation technique. The in vitro biological properties were evaluated by means of both direct and indirect cell tests, i.e., neutral red (NR) uptake and MTT assay, using murine long bone osteocyte Y4 (MLO-Y4) cells: the cellular viability of BGMSN was higher compared to cellular viability of 45S5, both in direct and indirect tests. Finally, the in vitro bioactivity test by soaking samples in simulated body fluid (SBF) showed high dissolution rate, with a good rate of formation of hydroxyapatite.

Effects of different sintering temperatures on thermal, physical, and morphological of SiO2-Na2O-CaO-P2O5 based glass-ceramic system from vitreous and ceramic wastes

This research involved comprehensive studies on thermal, physical, and morphological properties of SiO2-Na2O-CaO-P2O5 (SNCP) glass-ceramic at various sintering temperatures. The study in SNCP glass-ceramic using soda-lime-silica (SLS) wastes glass and clam shell (CS) wastes as the main raw of materials via conventional melt-quenching technique and solid state sintering are interesting and challenging by considering the research using waste materials to fabricate novel SNCP glass-ceramic. The main peaks, Na3PO4 and Ca3Na6Si6O18 were assigned to high crystallization temperature (Tc) at 650-950?C. The density of samples increases at 550-750?C and decreases at 850-950?C due to the increase of sample thickness and higher specific volume at high sintering temperature. FESEM micrograph showed that existed porous increased at sintering temperature 850-950?C contributes effect to low densification of the sample.

The Ferroelectricity and Crystallinity of Zirconia, Hafnia and Hafnium Zirconium Oxide (HZO) Ultrathin Films Prepared by Atomic Layer Deposition With and Without Post-Annealing

Large stable ferroelectricity in hafnium zirconium oxide (HZO) solid solution ultrathin films (including pure zirconia (ZrO2) and hafnia (HfO2)) and ZrO2/HfO2 bilayer ultrathin films of thickness ranging from 5–12 nm, prepared by thermal atomic layer deposition or remote plasma atomic layer deposition (RP-ALD) has been demonstrated. Ferroelectric crystallization of the ZrO2 ultrathin film with high-pressure orthorhombic (o) space group Pbc21 could be achieved without post-annealing due to the plasma-induced thermal stresses experienced by the film during the RP-ALD process. In contrast, for the ZrO2/HfO2 bilayer ultrathin film, due to the high crystallization temperature of HfO2, post-annealing was needed to achieve sufficient confinement of the sandwiched HfO2 layer by the ZrO2 top layer and Si bottom substrate to promote the high-pressure ferroelectric o-phase in HfO2. The ferroelectric properties of the HZO ultrathin films prepared by RP-ALD were highly dependent on the Hf-to-Zr ratio — an increasing amount of HfO2 has been found to be detrimental to the ferroelectricity, mainly due to the high crystallization temperature of HfO2. Without post-annealing, the ferroelectricity of the HZO ultrathin films was governed by the relative amounts of the amorphous phase and the ferroelectric o-phase induced by the plasma treatment. While with post-annealing, the ferroelectricity was governed by the relative amounts of the ferroelectric o-phase and the non-ferroelectric monoclinic (m) phase.