Investigating the effect of nano-structured magnetic particles lanthanum strontium manganite on perovskite solar cells (original) (raw)
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Journal of Materials Science: Materials in Electronics, 2020
Lanthanum Strontium Manganite (La 1-x Sr x MnO 3) perovskite nanoparticles are prepared by ultrasonication assisted hydrothermal method with different Sr concentration (x = 0.1, 0.3, 0.5). The structural, magnetic and electrical properties of the prepared samples are studied by powder X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometry (VSM) and impedance spectroscopy. The Powder XRD and EDX studies confirmed the formation of LaSrMnO 3. The powder XRD patterns show that the crystallite size decreases from 27.2 to 19.7 nm as the Sr concentration increases from x = 0.1 to x = 0.5. A shift in peak position towards higher angle indicates the replacement of La ions by Sr ions in the LaMnO 3 lattice. Electron microscopic images show that the La 1-x Sr x MnO 3 samples having both spherical and polygon morphology with decreasing particle size as the Sr concentration increases. The selected area electron diffraction (SAED) pattern confirms the polycrystalline nature of the La 1-x Sr x MnO 3 (x = 0.5) nanoparticles. The magnetic study indicates that the La 1-x Sr x MnO 3 samples exhibits ferromagnetism at room temperature, which increases with increasing of Sr concentration. Dielectric analysis shows the dielectric constant decreases with the function of frequency and increases with Sr content. With increase in frequency and Sr ions dopant concentration, the AC conductivity of the prepared samples is increased. The Cole-Cole plot shows the different radii of the semicircles exhibit the resistances of La 1-x Sr x MnO 3 samples are highly dependent on the Sr concentration.
Journal of Solid State Chemistry, 2013
Syntheses of nanocrystalline perovskite phases of the general formula La 1−x Sr x MnO 3+δ were carried out employing sol-gel technique followed by thermal treatment at 700-900 1C under oxygen flow. The prepared samples exhibit a rhombohedral structure with space group R3c in the whole investigated range of composition 0.20≤x≤0.45. The studies were aimed at the chemical composition including oxygen stoichiometry and extrinsic properties, i.e. size of the particles, both influencing the resulting structural and magnetic properties. The oxygen stoichiometry was determined by chemical analysis revealing oxygen excess in most of the studied phases. The excess was particularly high for the samples with the smallest crystallites (12-28 nm) while comparative bulk materials showed moderate nonstoichiometry. These differences are tentatively attributed to the surface effects in view of the volume fraction occupied by the upper layer whose atomic composition does not comply with the ideal bulk stoichiometry.
Double perovskite oxides La2NiMnO6 and La2Ni0.8Fe0.2MnO6 for inorganic perovskite solar cells
Наносистемы: физика, химия, математика, 2022
Nanopowders of La 2 Ni 0.8 Fe 0.2 MnO 6 and La 2 NiMnO 6 double perovskite oxides were synthesized by glycine-nitrate combustion method. The obtained materials were characterized using X-ray diffraction, scanning electron microscopy and optical measurements. Thin nanostructured layers based on the prepared materials were used as light absorbing layers for fabrication of inorganic perovskite solar cells (PSCs). Electron transport layers for the PSCs were prepared using TiO 2 and ZrO 2 nanostructured layers. The best performance of 3.7 % under AM1.5G illumination was obtained for the PSC structure glass/FTO
Magnetic, resonance and transport properties of nanopowder of La0.7Sr0.3MnO3 manganites
Journal of Magnetism and Magnetic Materials, 2010
X-ray powder diffraction, magnetization, transport and magnetic resonance measurements of nanosize La 0.7 Sr 0.3 MnO 3 (LCMO) manganites have been performed. The nanosize manganites were synthesized with a co-precipitation method at different (600, 700, 800 and 1000 1C) temperatures. The crystal structure of the nanopowders obtained was determined to be perovskite-like with a rhombohedral distortion (the space group R3 c). The average size of synthesized nanoparticles (from 17 to 88 nm) was estimated using the X-ray diffraction and low temperature adsorption of argon methods. All the nanosize manganites show ferromagnetic-like ordering. Both the Curie temperature and magnetization decrease with reducing the particle size. The decrease of magnetization is due to the disordered surface shell of particles. The disordered surface layer is a source of the surface anisotropy and is responsible for the increase of coercivity. Temperature dependences of the magnetic resonance spectra parameters have allowed obtaining information on dynamics of magnetic properties in the nanoparticle systems. The resistivity was established to become higher by reducing the particles' size and increases to a great extent in nanoparticles with the smallest average size at low temperatures. The magnetic entropy was shown to be smaller for the small particles. Using the temperature dependence of magnetic entropy the relative cooling power of the nanosize samples studied was evaluated.
Perovskite type lanthanum manganite: Morpho-structural analysis and electrical investigations
Journal of Rare Earths, 2018
Perovskite-type oxides of LaMnO 3 were synthesized by means of the sol-gel method, in the presence of citric acid as gelling agent. The precursors used were Mn(NO 3) 2 •H 2 O, La 2 O 3 , and NaOH, mixed in the stoichiometric ratio to obtain perovskite materials. The obtained gel was heat-treated at 400, 600 and 800 °C respectively, for 6h. X-ray diffraction and FT-IR spectroscopy were used to analyze the phase transformation as a function of temperature, and the Rietveld refinement was used in order to characterize the materials obtained structurally. The average crystallite size of the products was calculated from XRD data and the average particle size was measured from the TEM micrographs. At 600°C, the synthesized compound is well-crystallized, showcases a perovskite structure (Pm-3m space group), and exhibits uniform and homogeneous hexagonally-shaped particles, with sizes in the 20-50 nm range. Complex impedance measurements in the 20 Hz-2 MHz frequency range were carried out at different temperatures (26-115 °C), and the electrical conduction mechanism was discussed.
Journal of Solid State Chemistry, 2002
An intense e4ort has recently been devoted to studying the interplay between structure, magnetism, and transport in manganese perovskite Ln 1؊x A x MnO 3 (Ln ؍ La, Pr, Nd, Sm; A ؍ Ca, Ba, Sr). As a function of temperature, applied magnetic 5eld, doping, A-site ionic radius 1r A 2, and A-site size disorder, this system displays a rich phase diagram for both magnetotransport and structural properties. We have investigated the structural, magnetic, and transport properties of (La 1؊x Nd x ) 0.7 Sr 0.3 MnO 3 . The crystal structure was examined by X-ray powder di4raction which indicated that all the samples were single phase and revealed a transition from rhombohedral to orthorhombic structure with increasing x. The magnetization and resistivity investigation shows that for all values of x, (La 1؊x Nd x ) 0.7 Sr 0.3 MnO 3 are ferromagnetic+metallic at low temperatures and paramag-netic+semiconductor above the Curie temperature T c .