Themed collection Perovskites

Welcome to this themed issue of Dalton Transactions focusing on perovskites.

Accurate control of residual defect density is required for reliable investigation and use of ferroelectric materials.

We overview investigations highlighting the significance of interface engineering of oxygen displacement as a tool for phase control of strained oxides.

In the past two years, the power conversion efficiency (PCE) of organic–inorganic hybrid perovskite solar cells has significantly increased up to 20.1%.

This perspective reviews recent studies on the fabrication of dielectric oxynitride perovskites for powders, ceramics, compacts and thin films.

Recent theoretical and experimental studies showing how polar structures or ferroelectricity arise in layered perovskites are highlighted.

Perovskite materials exhibit the ability to accommodate large levels of oxyanions (from carbonate to phosphate). This review highlights work in this area from superconductivity to solid oxide fuel cells.

The solid solution between bismuth ferrite and potassium niobate indicates a similar series of phase transitions to PZT.

BiCoO₃ in bulk and in film geometry. Marked are the Co spin states.

Unit cell and non-stoichiometry of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ in O₂, demonstrating oxidation followed by thermal reduction and formation of a hexagonal phase is reported.

Layered-type ordering of Ba and Gd atoms in BaGdMnFeO_6−δ perovskite studied by HAADF-STEM and EELS mapping.

Powder X-ray diffraction patterns, magnetic susceptibility as a function of temperature, and polyhedral representation along the c-axis of the BaLaCuSbO₆ double perovskite have been reported.

In La_yCu₃Ru_xTi_4−xO_12+δ ruthenium remains as Ru⁴⁺, while the Cu valence decreases from +2 to +1.6 with increasing x.

The crystal structure of the proton conducting perovskite, BaCe_0.8Y_0.2O_3−δ, is found to show a remarkable dependence on temperature and humidity, with hydration favouring enhanced octahedral tilting.

A non-aggregated Zn(II)octa(2,6-diphenylphenoxy) phthalocyanine (coded as TT80) has been used as a hole-transporting material for perovskite solar cells.

Phase diagram of the ternary system CaTiO₃–La_2/3TiO₃–SrTiO₃. All numbers represent calcium content. Solid symbols represent the samples in the series La_0.2Sr_0.7−xCa_xTiO₃ studied in this work and analysed using NPD.

The A³⁺M³⁺O₃ perovskites with ions in the fixed oxidation state exhibit slower reduction of structural distortion and the tolerance factor with temperature than the A²⁺M⁴⁺O₃.

Four new double perovskites, SrLaMReO₆ (M = Mg, Mn, Co, Ni), are characterized by X-ray and neutron diffraction, XANES, magnetic susceptibility, and μSR.

The correlation between the critical temperature, T_c, and the apical oxygen distance, the buckling angle and the charge transfer energy (Δ) with the oxidation, in the family of materials: Mo_0.3Cu_0.7Sr₂ErCu₂O_y.

TlCrO₃ perovskite has many peculiarities in comparison with RCrO₃ (R = rare earths), originating from the strong covalency of Tl³⁺–O bonds.

Thermodynamic grüneisen parameter and bond valence parameters for strontium cerate perovskite.

Crystal chemistry modification stabilized antiferroelectricity in NaNbO₃-based polycrystalline ceramics.

The Raman spectra of A₂MWO₆ double perovskites with various symmetries have been studied.

A series of isovalently A-site substituted relaxor dielectric tetragonal tungsten bronzes of general formula Ba_6−x−ySr_xCa_yGaNb₉O₃₀ were investigated.

Hydrothermal synthesis produces polycrystalline NaBi(Ti_1−xZr_x)O₆ with small composition range; densified x = 0.01 material shows favourable piezoelectric coefficient and permittivity.

The redox characteristics of the two manganese-based oxygen storage materials were studied to clarify the effects of isovalent substitution neighboring the “active” sites for oxygen intake/release.

Powder neutron diffraction, Co-Kβ XES spectra and a polyhedral view of the orthorhombic LaCo_0.71(1)V_0.29(1)O_2.97(3) perovskite.

High-spin ground state of Co³⁺ was found in brownmillerite-like Sr₂Co_1.2Ga_0.8O₅ by low-temperature NPD and XAS study.

The Dion–Jacobson type layered perovskites, APrNb₂O₇ (A = Rb, Cs), can be readily exchanged with (CuCl)⁺ at low temperatures to produce, (CuCl)PrNb₂O₇, a compound that shows interesting 2D antiferromagnetic behavior.

A novel anion-deficient perovskite-based compound with {110}-Layered B-cation ordering, Pb_2.4Ba_2.6Fe₂Sc₂TiO₁₃, was synthesized via the citrate-based route.

Magnetic moments show a surprising degree of spin canting in the antiferromagnetic structure of the brownmillerite Ca₂Cr₂O₅, obtained from the high pressure perovskite CaCrO₃ through hard-soft chemistry.

Phase behaviour in the layered perovskite LaTaO₄ has been analysed, including an unusual tilt-induced axial thermal contraction effect.

Mn₂CrSbO₆-perovskite was synthesized at high pressure in order to stabilize the small Mn²⁺ cations on the A-perovskite site. Mn₂CrSbO₆-ilmenite polymorph can be prepared, starting from the perovskite, by a “hard-soft” phase transformation increasing the temperature at room pressure.

Doping Ba₂YRuO₆ with Sr induces octahedral tilting and significantly impacts on the magnetic properties.

The crystal structure and topochemical modification of BaCoO_2.22 show that its cubic structure is tightly hold by the strong oxygen deficiency.

Synchrotron X-ray powder diffraction patterns of K_0.5Bi_0.5Ti_1−xZr_xO₃ (KBT-KBZ), showing the pseudocubic tetragonal region at all intermediate compositions in the solid-solution.

A large enhancement of ferroelectric polarizations in AA′MnWO₆ double perovskites through cation substitution is predicted and investigated using first-principles calculations.

Reductive lithium intercalation into A_nB_n−1O_3n cation deficient perovskite phases leads to the formation of Ba₅LiNb₄O₁₅, Ba₆LiTiNb₄O₁₈ and Ba₃LaLiNb₃O₁₂.

A-site deficiency does not survive in Sr_2−xFeMoO₆ and instead Mo-rich Sr₂Fe_1−yMo_1+yO₆ perovskites, characterised by the gradual disordering of Fe and Mo, form.

Controlled synthetic conditions yielded YInO₃:Eu³⁺ in both C-type and hexagonal modifications which exhibited a tremendous bearing of size and local structure on Eu³⁺ luminescence, all in a single compound.

The perovskite-type hybrid thiazolium tribromocadmate(II) exhibits two phase transitions at 180 and 146 K, accompanied by remarkable dielectric responses.