Synthesis, phase composition and magnetic properties of double perovskites of A(FeM)O4-x type (A=Ce; M=Ti)
TL;DR: In this paper, the phase composition, structural and magnetic properties of double perovskites Ce(FeTi)Ox obtained by solid phase synthesis were analyzed using scanning electron microscopy, energy dispersive and X-ray phase analysis, Mossbauer spectroscopy.
About: This article is published in Ceramics International.The article was published on 2019-05-01. It has received 77 citations till now. The article focuses on the topics: Cerium & Annealing (metallurgy).
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TL;DR: In this article, the influence of thermal annealing on changes in the structural properties and phase composition of metallic nanostructures based on cobalt, as well as the possibilities of using an anode material for lithium ion batteries was investigated.
113 citations
TL;DR: In this paper, a strong correlation between the level of chemical substitution and amplitude-frequency characteristics for investigated Co1/2Ni 1/2(Fe2-xDyx)O4 (0.08) spinels was detected.
105 citations
TL;DR: In this article, the effect of lithium doping on the structural and electrical properties of ferroelectric ceramics LixSr1-xTiO3 has been investigated, and it was found that an increase in lithium during the synthesis leads to phase transformations of the type Sr TiO3/TiO2 → SrTiO 3/ TiO2/Li2Ti3O7 → Sr
103 citations
TL;DR: In this article, the authors used the citrate gel process to extract dysprosium ions (Dy3+)-substituted nanosized ferrites (NFs) of composition [Ni0.5Co 0.5]-DyxFe2-x)O4 (x ≤ 0.08) and applied the Mossbauer spectroscopy methods and vibrating sample magnetometry (VSM) to analyse the magnetic properties of the samples.
98 citations
TL;DR: In this paper, a study of the radiation resistance of the structural, mechanical, and strength properties of synthesized CuBi2O4 films depending on the film thickness and radiation dose is presented.
Abstract: The aim of this work is to assess the prospects of using CuBi2O4 composite films of various thicknesses as protective coatings against exposure to ionizing radiation of up to 150 MeV and doses of 1 × 1013–1015 ion/cm2, characteristic of the effects of overlapping cascade defects in the target. The relevance and novelty of the study lies in the search for alternative sources of screening for the effects of radiation damage to microelectronic devices without a significant increase in the mass–overall dimensions of microcircuits. This paper presents the results of a study of the radiation resistance of the structural, mechanical, and strength properties of synthesized CuBi2O4 films depending on the film thickness and radiation dose. Electrochemical deposition was used as a synthesis method, which allows one to control with high accuracy the phase composition and morphology of the synthesized films. Synthesized films were shown to possess a significant degree of stability to irradiation with the increasing film thickness from 5 to 10 μm. Moreover, in the case of films with a thickness of 3 μm, a decrease in the strength and structural properties is due to phase transition processes initiated by irradiation due to the transfer of energy to the crystalline subsystem as a result of elastic and inelastic collisions.
77 citations
References
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TL;DR: Jeon et al. as discussed by the authors synthesize a fluorene-terminated hole-transporting material with a fine-tuned energy level and a high glass transition temperature to ensure highly efficient and thermally stable perovskite solar cells.
Abstract: Perovskite solar cells (PSCs) require both high efficiency and good long-term stability if they are to be commercialized. It is crucial to finely optimize the energy level matching between the perovskites and hole-transporting materials to achieve better performance. Here, we synthesize a fluorene-terminated hole-transporting material with a fine-tuned energy level and a high glass transition temperature to ensure highly efficient and thermally stable PSCs. We use this material to fabricate photovoltaic devices with 23.2% efficiency (under reverse scanning) with a steady-state efficiency of 22.85% for small-area (~0.094 cm2) cells and 21.7% efficiency (under reverse scanning) for large-area (~1 cm2) cells. We also achieve certified efficiencies of 22.6% (small-area cells, ~0.094 cm2) and 20.9% (large-area, ~1 cm2). The resultant device shows better thermal stability than the device with spiro-OMeTAD, maintaining almost 95% of its initial performance for more than 500 h after thermal annealing at 60 °C. Interfacial losses between device layers play a key role in determining characteristics of solar cells. Jeon et al. address this in perovskite solar cells by synthesizing a hole-transporting layer that is better matched to the surrounding layers, and show high-efficiency and high-stability devices.
1,771 citations
TL;DR: A semiconductor that can be processed on a large scale with a bandgap around 1.8 eV could enable the manufacture of highly efficient low cost double-junction solar cells on crystalline Si.
Abstract: A semiconductor that can be processed on a large scale with a bandgap around 1.8 eV could enable the manufacture of highly efficient low cost double-junction solar cells on crystalline Si. Solution-processable organic–inorganic halide perovskites have recently generated considerable excitement as absorbers in single-junction solar cells, and though it is possible to tune the bandgap of (CH3NH3)Pb(BrxI1–x)3 between 2.3 and 1.6 eV by controlling the halide concentration, optical instability due to photoinduced phase segregation limits the voltage that can be extracted from compositions with appropriate bandgaps for tandem applications. Moreover, these materials have been shown to suffer from thermal degradation at temperatures within the processing and operational window. By replacing the volatile methylammonium cation with cesium, it is possible to synthesize a mixed halide absorber material with improved optical and thermal stability, a stabilized photoconversion efficiency of 6.5%, and a bandgap of 1.9 eV.
935 citations
TL;DR: Light excitation enhances by several orders of magnitude the ionic conductivity of methylammonium lead iodide, the archetypal metal halide photovoltaic material, and straightforwardly leads to a hitherto unconsidered photodecomposition path of the perovskite.
Abstract: In the same way as electron transport is crucial for information technology, ion transport is a key phenomenon in the context of energy research. To be able to tune ion conduction by light would open up opportunities for a wide realm of new applications, but it has been challenging to provide clear evidence for such an effect. Here we show through various techniques, such as transference-number measurements, permeation studies, stoichiometric variations, Hall effect experiments and the use of blocking electrodes, that light excitation enhances by several orders of magnitude the ionic conductivity of methylammonium lead iodide, the archetypal metal halide photovoltaic material. We provide a rationale for this unexpected phenomenon and show that it straightforwardly leads to a hitherto unconsidered photodecomposition path of the perovskite.
400 citations
12 Oct 2012
TL;DR: SpectrRelax as mentioned in this paper is an application for analysis and fitting of absorption and emission Mossbauer spectra of isotopes with 1/2 ↔ 3/2 transitions.
Abstract: The SpectrRelax application was created for analysis and fitting of absorption and emission Mossbauer spectra of isotopes with 1/2 ↔ 3/2 transitions. Available models include a single Pseudo-Voigt line, doublet, and a sextet, a number of relaxation models, and a distribution of hyperfine/relaxation parameters of any model. SpectRelax can evaluate user supplied analytical expressions of model parameters and their error estimates. Complex parameter constraints or even new models can be implemented by setting parameter values to analytical expressions. Optimal model parameters search is performed using a maximum likelihood criterion in a Levenberg-Marquardt (L-M) algorithm. In the search process, a matrix of linear correlation coefficients between model parameters is calculated along with the error estimates, which allows better understanding of the optimized results. Partial derivatives of the model functions are evaluated using a "dual numbers" algorithm, which provides exact derivatives values at any point and improves the L-M method convergence. SpectrRelax runs under Windows operating systems by Microsoft. The application has a modern graphical user interface with extensive model editing and preview capabilities.
261 citations
TL;DR: In this paper, the authors demonstrate LEDs made from in situ grown CsPbX3 quasi 2D/3D thin films that are color tunable across the entire visible spectrum.
Abstract: Ruddlesden–Popper phase inorganic metal halide perovskites are promising candidates for efficient light-emitting diodes (LEDs) with high brightness and color purity. Here, we demonstrate LEDs made from in situ grown CsPbX3 quasi 2D/3D thin films that are color tunable across the entire visible spectrum. CsPbX3 nanosheets are used to produce RP phase perovskites using butylammonium as a separating ligand to create BA2Csn–1Pbn(Br/Y)3n+1 2D/3D mixed halide thin films, where Y = Cl or I. The number of CsPbBr3 monolayers in these crystals was optimized by changing the butylammonium concentration. We demonstrate a stable perovskite phase with thin emission line widths providing points covering the edge of the CIE triangle and a maximum red/green/blue coverage of ∼130% of the National Television System Committee color standard. Additionally, we are able to report record efficiencies for blue emitting perovskite nanocrystal LEDs with a maximum external quantum efficiency (EQE) of 2.4% and 6.2% at 465 and 487 nm a...
219 citations