Pb2+ Defects in perovskite-like KMgF3 crystals

Abstract

The physical properties of Pb²⁺ impurities in the perovskite-like lattice of KMgF₃ are very similar to those of (ns)² ions in alkali halides. The impurity inhomogeneous distribution leads to high dopant levels in the bottom region of the crystals, with a segregation coefficient equal to 0. 020. The optical features of the 336 nm emission support its attribution to luminescence of Pb²⁺ ions from the relaxed excited B state.     

Dye solar cells efficiency maps: a parametric study

In this work we present a numerical simulation of a dye solar cell efficiency using a drift-diffusion model for the complete cell. The physical parameters such as the active layer thickness, the electron mobility and the dye spectrum are varied systematically in a range of values individuated experimentally, in order to obtain efficiency maps that reveal interesting features in this kind of devices.     

Synthesis and Characterization of 2d Ferromagnetic (RNH3)2CrX4 Containing Mixed-Halides,R = CnH2n+1, X = Br,C1

The bis(benzylammonium)tetrahalogenochromate(II), (C₆H₅CH₂NH₃)₂CrBr₃. ₃Cl₀. 7, has been synthesized and characterized. The crystal structure is related to that of K₂NiF₄. The compound is ferromagnetic and the Curie temperature T_C (T_C= 49 K) has been measured by a mutual inductance technique. The susceptibility increases sharply at T_C and then shows a drop-off below T_C, typical of a single-domain powder sample. The compound is found to behave as a typical 2D easy plane ferromagnet.     

Volatiles,color characteristics and other physico–chemical parameters of commercial Moroccan honeys

Seven commercial Moroccan honeys were considered for chemical characterisation. Volatile fraction, total polyphenols content, antioxidant and antiradical activities were evaluated by employing different analytical methodologies. Several physical parameters such as refractive index, pH, water content, solids content and colour were measured. Volatile fraction revealed an abundant presence of cis- and trans-linalool oxide in the seven studied samples. The presence of high levels of compounds related to the Maillard reaction, like furfural and hydroxymethylfurfural, could be the result of thermal treatments used to liquefy commercial honeys or of long storage times. The CIE L^*a^*b^*C_ab^*h_ab° chromatic coordinates confirmed the advanced stage of the Maillard reaction, showing L^* values lower than the common values found for honey of similar typologies.