Optical, electrical and magnetic properties of lanthanum strontium manganite La1-xSrxMnO3 synthesized through the citrate combustion method.

Generally, strontium-doped lanthanum manganites (LSM) are materials connected ordinarily as cathodes in the solid oxide fuel cell (SOFC). In this study, the structural, optical, electrical and magnetic properties of La1-xSrxMnO3 (x = 0.2, 0.5, 0.8) synthesized using an organic acid precursor strategy were investigated, based on using citric acid as a fuel. Evidently, the results disclosed that a pure single monoclinic LSM phase was obtained from the thermally treated precursors annealed at 1000 °C with an annealing time of 2 h. The microstructure of the formed sample relied on the Sr2+ ion content. Moreover, a good optical transparency of 45-60% in a wide range of wavelengths between 800 and 1800 nm for all samples substituted by Sr2+ ions was performed. The optical band gap energy was increased from 2.09 to 2.76 eV by increasing the Sr2+ ion molar ratios. The trend in the calculated refractive index, the high frequency dielectric constant (εα) and the static dielectric constant (ε0) of all the produced samples can be linked to an increase in the Sr2+ ion concentration. Moreover, the magnetic properties were enhanced with increasing Sr2+ ion content.

Copper-Substituted Lead Perovskite Materials Constructed with Different Halides for Working (CH3NH3)2CuX4-Based Perovskite Solar Cells from Experimental and Theoretical View.

Toxicity and chemical instability issues of halide perovskites based on organic-inorganic lead-containing materials still remain as the main drawbacks for perovskite solar cells (PSCs). Herein, we discuss the preparation of copper (Cu)-based hybrid materials, where we replace lead (Pb) with nontoxic Cu metal for lead-free PSCs, and investigate their potential toward solar cell applications based on experimental and theoretical studies. The formation of (CH3NH3)2CuX4 [(CH3NH3)2CuCl4, (CH3NH3)2CuCl2I2, and (CH3NH3)2CuCl2Br2] was discussed in details. Furthermore, it was found that chlorine (Cl-) in the structure is critical for the stabilization of the formed compounds. Cu-based perovskite-like materials showed attractive absorbance features extended to the near-infrared range, with appropriate band gaps. Green photoluminescence of these materials was obtained because of Cu+ ions. The power conversion efficiency was measured experimentally and estimated theoretically for different architectures of solar cell devices.