Perovskite-graphene nanocomposites of rare-earth LaFeO3-rGO and LaFeO3 nanoparticles are synthesized and characterized. The preparation was done by citrate sol-gel method. The structural characterization has been performed using XRD and FT-IR. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used to analyze the morphology of the prepared nanocomposite. Vibrating sample magnetometer (VSM) was used to study the magnetic properties of the investigated samples. Introducing graphene to the structure results increase in MS. Also, the optical and thermal properties have been measured and discussed, and the effect of graphene is observed where it decreases the band gap than reported for pure LaFeO3 nanoparticles.

Graphene influence on the structure, magnetic, and optical properties of rare-earth perovskite

Rapid development in two-dimensional layered perovskite materials and their application in solar cells

Diammonium series of Cu hybrid perovskites of the formula [(NH3)(CH2)
 n
 (NH3)]CuCl4, n = 6–9 are prepared from an ethanolic solution in stoichiometric ratio 1:1 (organic/inorganic). Formation of the desired material was confirmed and characterizes by microchemical analysis, FTIR, XRD and XPS spectra. The structure consists of corner-shared octahedron [CuCl4]2− anion alternative by organic [(NH3)(CH2)
 n
 (NH3)]2+ cations. The organic and inorganic layers form infinite 2D sheet that are connected via NH···Cl hydrogen bond. The calculated lattice potential energy U
 pot (kJ/mol) and lattice enthalpy ΔH
 L (kJ/mol) are inversely proportional to the molecular volume V
 m (nm3) and organic chain length. Optical properties show strong absorption peak at UV–visible range. The band gap energy calculated using Kubelka–Munk equation shows the decrease of the energy gap as organic chain length increases. The introduction of bromide ion to [(NH3)(CH2)
 n
 (NH3)]CuCl2Br2 denoted 2C7CuCB hybrid has shifted the energy gap to lower values from 2.6 to 2.18 eV for 2C7CuCl (yellow) and 2C7CuCB (brown), respectively, at the same organic chain length. All elements of [(NH3)(CH2)9(NH3)]CuCl4 and [(NH3)(CH2)7(NH3)]CuCl2Br2 were found in XPS spectra, as well as valence band spectra.

Effect of organic chain length on structure, electronic composition, lattice potential energy, and optical properties of 2D hybrid perovskites [(NH3)(CH2) n (NH3)]CuCl4, n = 2–9

https://onlinelibrary.wiley.com/doi/pdf/10.1002/aenm.201802366

What Defines a Perovskite

In this work the crystal structure by single crystal X-ray measurement and optical properties of 1D propane-1,2-di­ammonium penta­chlorobis­muthate [NH3CH2CH(NH3)CH3]BiCl5 organic–inorganic hybrid perovskite are presented. It is prepared by mixing ethano­lic solution of equimolar ratios (1:1) of its basic components. The title compound crystallized in the noncentrosymmetric orthorhombic space group Pca21 with Z = 8 molecules per unit cell. The unit-cell parameters are a = 19.8403 (7) A, b = 6.3303 (2) A, c = 19.0314 (7) A. The vibrational spectra are studied by Raman and infrared spectroscopy. The optical properties show a strong absorption in the ultraviolet region, the band gap energy Eg is found to be 3.15 eV. Cathodoluminescence measurements are also discussed.

Crystal structure, vibrational spectroscopy and optical properties of a one-dimensional organic-inorganic hybrid perovskite of [NH3CH2CH(NH3)CH2]BiCl5.

Synthesis, structure, lattice energy and enthalpy of 2D hybrid perovskite [NH3(CH2)4NH3]CoCl4, compared to [NH3(CH2)nNH3]CoCl4, n=3–9

Structure Investigation by Neutron Diffraction and X-Ray Diffraction of Graphene Nanocomposite CuO–rGO Prepared by Low-Cost Method

The 2-D organic–inorganic hybrid perovskites of the formula [(NH3)(CH2)7(NH3)]CuClxBr4−x, x = 0, 2 and 4 were prepared by slow evaporation from ethanolic solution in stoichiometric ratio 1:1 (organic/inorganic). Microchemical analysis and x-ray diffraction (XRD) were used to confirm the formation of the presently investigated hybrids. Differential scanning calorimetry (DSC) indicated order–disorder transitions at T1 = 357 K, T2 = 388 K, and T3 = 398 K for x = 0, 2 and 4 of the three heptain diammonium Cu hybrid perovskites, respectively. These transitions are in good agreement with the electrical permittivity results at different frequencies and temperatures. Optical properties and estimated band gap energy reveal that the band gap energy decreases sharply with replacement of Cl ion by Br ion where the band gap energy of [(NH3)(CH2)7(NH3)]CuBr4, x = 0 (denoted 2C7CuBr) is 1.6 eV (brown color) and for [(NH3)(CH2)7(NH3)]CuCl4, x = 4 (denoted 2C7CuCl) is 2.6 eV (yellow color). The differential magnetic susceptibility of 2C7CuBr in the temperature range 80–300 K indicates the effective magnetic moment μeff = 2.05 BM.

Ahmed S. Abdel-Rahman

Papers

Graphene influence on the structure, magnetic, and optical properties of rare-earth perovskite

Synthesis, structure, lattice energy and enthalpy of 2D hybrid perovskite [NH3(CH2)4NH3]CoCl4, compared to [NH3(CH2)nNH3]CoCl4, n=3–9

Crystal structure, vibrational spectroscopy and optical properties of a one-dimensional organic-inorganic hybrid perovskite of [NH3CH2CH(NH3)CH2]BiCl5.

Structure Investigation by Neutron Diffraction and X-Ray Diffraction of Graphene Nanocomposite CuO–rGO Prepared by Low-Cost Method

Fascinating Physical Properties of 2D Hybrid Perovskite [(NH 3 )(CH 2 ) 7 (NH 3 )]CuCl x Br 4−x , x = 0, 2 and 4