Zirconium Halide Research Articles

Comprehensive Defect Suppression in Te‐Doped Cs2ZrCl6 Perovskite Nanoparticles for Highly Efficient and Thermally Stable White Light‐Emitting Diodes

AbstractCesium zirconium halide (e.g., Cs2ZrCl6:Te or CZCT) perovskites have garnered significant interest due to their unique optical properties. However, there have been no reports of CZCT perovskite nanoparticles (PNPs) that simultaneously offer high efficiency and thermal stability. Here, a comprehensive defect suppression strategy is reported to achieve CZCT PNPs with these attributes. First, the inner defects of CZCT perovskite microcrystals (PMCs) are minimized by controlling crystallization kinetics precisely. Second, the PNPs are obtained from PMCs via top‐down fabrication, and the surface defects of PNPs are passivated via the hydroxyl groups of alkyl‐terminated silica‐oligomer shell (ASO). The resulting CZCT@ASO PNPs show the highest photoluminescence quantum yield (PLQY) of 96% and high thermal stability among the reported conventional CZCT emitters. Finally, white light‐emitting diodes (WLEDs) are integrated by using CZCT@ASO PNPs as the down‐color converters, achieving a color coordinate of (0.31, 0.33) and a color rendering index of 86. These results demonstrate that core/shell CZCT@ASO PNPs have great potential as phosphors for lighting applications.

Supramolecular assembly of blue and green halide perovskites with near-unity photoluminescence.

The metal-halide ionic octahedron is the optoelectronic unit for halide perovskites, and a crown ether-assisted supramolecular assembly approach can pack various ionic octahedra into tunable symmetries. In this work, we demonstrate near-unity photoluminescence quantum yield (PLQY) blue and green emission with the supramolecular assembly of hafnium (Hf) and zirconium (Zr) halide octahedral clusters. (18C6@K)2HfBr6 powders showed blue emission with a near-unity PLQY (96.2%), and green emission was also achieved with (18C6@K)2ZrCl4Br2 powders at a PLQY of 82.7%. These highly emissive powders feature facile low-temperature solution-based synthesis conditions and maintain high PLQY in solution-processable semiconductor inks under ambient conditions, and they were used in thin-film displays and emissive three-dimensional-printed architectures that exhibited high spatial resolution.

Heavy atom-doped thermally activated delayed fluorescence cesium zirconium halides for efficient X-ray imaging

A heavy atom (Hf)-doped Cs2ZrCl6 scintillator with strong blue emission, large Stokes shift, and smaller ΔE(S1–T1) shows a higher light yield, a low detection limit, and a higher spatial resolution, as well as good irradiation stability.

Theoretical investigation of the structural stability, electronic and optical properties of the double perovskite Cs2ZrX6 (X=Cl, Br, I)

In recent years, in order to solve the energy issue researchers have performed much investigations, among which inorganic metal halide chalcogenides have received extensive attention in the field of materials, energy and other fields for their excellent photovoltaic properties. However, the traditional halide chalcogenide has two deadly deficiencies, poor thermal stability and the presence of toxic lead elements, which prevent its applications. Compared with ABX3-type halide chalcogenides, double lead-free perovskites usually have the advantages of better thermal stability and less toxicity, which makes it easier to be commercialized. In addition, elemental substitution methods can be employed to modulate their energy bands and optical properties. Here, the structural stability, electronic and optical properties, and thermodynamic properties of cesium zirconium halide double perovskites Cs2ZrX6 (X = Cl, Br, I) are systematically investigated based on density functional theory (DFT) to predict their applications in the photovoltaic and optoelectronic industries. The computational results show that these cesium zirconium halide double perovskites have very good structural stability as well as special optical properties such as strong light absorption, large dielectric constant, and low reflectivity. Moreover, all of them belong to direct bandgap semiconductors and possess small effective masses, which indicates that the double perovskites could be potential candidates for future optoelectronic devices and applications.

Zirconium Halide Complexes: Synthesis, Structure, and Practical Applications

Zirconium Halide Complexes: Synthesis, Structure, and Practical Applications

Chemical Vapor Deposition of Zirconium Compounds: A Review

Coatings of zirconium compounds are used in a wide variety of fields, yet an understanding and descriptions of deposition mechanisms are scant in the public literature. The mechanisms of deposition for metallic zirconium, ZrC, ZrN, ZrO2, ZrB2, and zirconium silicides are discussed based on the direct vapor deposition research of those compounds where possible or compared to complementary titanium systems when direct research is lacking. Both inorganic and organometallic deposition systems are discussed. As a class of compounds, an understanding of the vapor deposition mechanisms can be significantly improved by investigations on metallic zirconium deposition by zirconium halides and hydrogen and by in situ analysis techniques such as Fourier-transform infrared (FTIR) spectroscopy or x-ray photoelectron spectroscopy (XPS).

Галогенидные комплексы циркония. Синтез, строение, возможности практического применения

Obtaining methods, some reactions, and structural features of zirconium halide complexes, as well as examples of their possible applications have been systematized and described, based on the analysis of the literature published mainly from 2018 until 2021. In discussion of the synthetic methods the main attention is focused on the most effective approaches for preparing such compounds. Reactions of zirconium complex formation are studied. Information about biological and catalytic activity of some zirconium derivatives is given.

Janus zirconium halide ZrXY (X, Y = Br, Cl and F) monolayers with high lattice thermal conductivity and strong visible-light absorption.

In this work, the structural, mechanical, and electronic properties of Janus zirconium halide monolayers have been systematically investigated using the first-principles calculations. After verifying the mechanical and dynamical stability of these monolayers, their electronic band structures have been predicted. These Janus monolayers have band gaps of 1.51-1.96 eV, which indicates their suitability for visible light absorption. The relaxation time and mobility of charge carriers are estimated using deformation potential theory, and the mobility of these monolayers has been predicted to be of the order ∼102 cm2 V-1 s-1. The lattice thermal conductivity has been calculated by solving the phonon Boltzmann transport equation using ShengBTE software. At 300 K, the in-plane lattice thermal conductivity has values of 76.94, 54.18, and 95.87 W m-1 K-1 for ZrBrCl, ZrBrF, and ZrClF monolayers, respectively. The higher group velocity and small anharmonic three-phonon scattering rate are the main reasons for the high lattice thermal conductivity of the ZrClF monolayer. The real and imaginary parts of the dielectric function are calculated to find the absorption coefficients and these monolayers have a high absorption coefficient of the order ∼106 cm-1 in the visible light range. Our results show that Janus zirconium halide monolayers are potential candidates for optoelectronic and photocatalytic applications.

Controlled growth of lead-free cesium zirconium halide double perovskite nanocrystals through a microfluidic reactor.

Vacancy-ordered Cs2ZrX6 (X = Cl, Br) double perovskite nanocrystals (NCs) have recently attracted increasing attention in optoelectronic applications due to their promising photoluminescence property, high photostability, and low toxicity. However, their ultra-fast reaction limits the growth control and kinetics study of these Cs2ZrX6 NCs. Here we report the synthesis of Cs2ZrX6 NCs through a microfluidic reactor and achievement of tunable emission wavelengths by controlling the NC size and hybrid halogen ions. Reaction kinetics study reveals that the amine ligand and reaction temperature play dominate roles in the growth and optical performance of the Cs2ZrX6 NCs. The effects of flow rate, precursors, and ligand ratio on the morphology and optical property of the NCs were also investigated. This study provides an insight into the growth kinetics of the Cs2ZrX6 perovskite NCs and their continuous production through a microfluidic reactor that could facilitate the development and optical application of lead-free vacancy-ordered double perovskite NCs.

Synthesis, characterisation, and dehydrocoupling ability of zirconium complexes bearing hindered bis(amido)silyl ligands.

Herein we detail the synthesis and characterisation of a series of zirconium compounds featuring the bis(amido)silyl ligand [(i)Pr2Si(NDipp)2](2-) (Dipp = 2,6-diisopropylphenyl). The functionalisation of bis(amido)silyl zirconium halide complexes with a variety of nucleophiles, such as LiNMe2, LiBH4 and MeLi, was explored and the resulting products showed a propensity to form anionic zirconate salts when the syntheses were carried out in THF. One of the zirconate products, [(i)Pr2Si(NDipp)2]Zr(NMe2)2·ClLi(THF)3, has the ability to catalyse the dehydrocoupling of primary and secondary amine-boranes at room temperature in aromatic solvents.

John D. Corbett (1926-2013)

John D. Corbett (1926-2013)

Thermodynamic Analysis and Growth of Zirconium Carbide by Chemical Vapor Deposition

Abstract Equilibrium calculations were used to optimize conditions for the chemical vapor deposition of zirconium carbide from zirconium halide + CxHy+H2+Ar system. The results show the CVD-ZrC phase diagram is divided into ZrC+C, ZrC and ZrC+Zr zones by C, Zr generating lines. For the same mole of ZrCl4 reactant, it needs higher concentration of CH4 to generate single ZrC phase than that of C3H6. Using these calculations as a guide, single-phase cubic zirconium carbide coatings were deposited onto graphite substrate.

Facile preparation of sol–gel-derived ultrathin and high-dielectric zirconia films for capacitor devices

This study successfully prepared zirconia ultrathin films from the sol–gel solution with dispersion of zirconium halide in 1-octanol solvent. The film was subjected to annealing treatments after sol–gel spin-coating, and the films of interest were evaluated. The amorphous morphology of the zirconia film was identified using high-resolution transmission electron microscopy and X-ray diffractometry. The plot of the current density with respect to the electric field demonstrates that the as-deposited film at 500°C annealing exhibited an inferior leakage current, whereas 600°C annealing stabilized the film with a satisfactory leakage current of 10−8 to 10–9A/cm2. The out-gassing behavior of the sol–gel-derived thin film was evaluated using a thermal desorption system, that is, atmospheric pressure ionization mass spectrometry. The dielectric constant of the film was dependent on the retention effect of the preparation solvents. The low residual solvent for the preparation of the thin film with 1-octanol solvent and 600°C annealing contributed to the superior high-k property.

91Zr Nuclear Magnetic Resonance Spectroscopy of Solid Zirconium Halides at High Magnetic Field

(91)Zr solid-state NMR spectra of zirconium halides and several fluorozirconates have been obtained at high magnetic fields up to 30 T using both the Hahn-Echo and the Quadrupolar Carr-Purcell-Meiboom-Gill sequences combined with the broadband Variable Offset Cumulative Spectrum technique. For the zirconium halides, the (91)Zr isotropic chemical shift covers a range of about 2000 ppm and shows a good correlation with Pauling's electronegativity and ionic potential of the halogen. For the fluorozirconate samples, in which the Zr atoms exhibit various coordination polyhedra, increasing the Zr coordination number and the mean Zr-F bond length leads to an increased isotropic shielding. In the studied compounds the (91)Zr quadrupolar coupling constants (C(Q)'s) range from 10.6 to 44.7 MHz. For 6-fold coordinated Zr sites, a correlation between C(Q) and the shear strain of the octahedron is observed, and we investigate the relationship between the C(Q) and the distortion of the polyhedron for 8-fold coordinated Zr sites using different distortion criteria.

Synthesis and Reactivity of Titanium and Zirconium Complexes Supported by a Multidentate Monoanionic [N2P2] Ligand

The coordination chemistry of titanium and zirconium complexes supported by the monoanionic multidentate ligand [N2P2] (where [N2P2] = tBuN−SiMe2N(CH2CH2PiPr2)2) is presented. The zirconium(IV) halide complex [N2P2]ZrCl3 (1) serves as a precursor to the alkyl species [N2P2]Zr(CH2SiMe3)3 (2) and [N2P2]ZrMe3 (3). The coordination behavior of the [N2P2] ligand in compound 3 is determined using NMR and X-ray diffraction data, and protonation of 3 results in the formation of the cationic species {[N2P2]ZrMe2}{B(C6H5)4} (4). The reduction of 1 in the presence of various traps leads to the isolation of ([N2P2]ZrCl)2(μ-η2:η2-N2) (5), ([N2P2]ZrCl)2(μ-Cl)2 (6), and [N2P2]ZrAr* (9). The titanium(III) halide complex [N2P2]TiCl2 (10) also serves as a precursor to alkyl and reduced species [N2P2]TiMe2 (11) and ([N2P2]TiCl)2(μ-N2) (12). Alkylation of 12 results in the formation of ([N2P2]TiCH2SiMe3)2(μ-N2) (13), and the degree of reduction of the N2 moiety in 12 and 13 is examined using X-ray crystallography and Raman s...

ChemInform Abstract: Chloroaluminate Ionic Liquids as Reagents for Isolating Soluble Hexanuclear Zirconium Halide Cluster Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chloroaluminate ionic liquids as reagents for isolating soluble hexanuclear zirconium halide cluster compounds.

Ambient-temperature chloroaluminate molten salts, mixtures of aluminum trichloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride (ImCl), have been used as solvents to excise and isolate centered hexanuclear zirconium halide clusters from their solid-state precursors. Cluster compounds synthesized via high-temperature reactions, KZr6CCl15 and Li2Zr6MnCl15, were dissolved into basic molten salts at 100-110 degrees C. The C-centered cluster compound, Im4Zr6CCl18, was isolated in 70% yield, and the Mn-centered cluster compound, Im5Zr6MnCl18.C7H(8).2CH3CN, was isolated in 54% yield. Im5Zr6BCl18 is efficiently oxidized by ferrocenium tetrafluoroborate, and one-electron-oxidized B-centered cluster, [(Zr6B)Cl18]4-, was isolated in 90% yield as the salt Im4Zr6BCl18.

Reduced zirconium halide clusters in aqueous solution.

Reduced hexazirconium halide cluster compounds have good solubility and stability in strongly acidic and/or halide-rich aqueous solutions. Cyclic voltammetric (CV) measurements in aqueous media established that [(Zr6BCl12)(H2O)6]2+/+ and [(Zr6BBr12)(H2O)6]2+/+ exhibited positive half-wave potentials (E1/2 = 0.059V and 0.160 V, respectively) vs the SHE, indicating that these clusters are only modestly reducing. Several new crystalline cluster compounds have been isolated from cold 12 M HCl solutions; the structures of each contain extended hydrogen-bonding water networks. Crystallographic data for these compounds are reported as follows: [Rb0.44(H3O)4.56][(Zr6BCl12)Cl6].19.44H2O (3), cubic, Im3m, a = 13.8962(3) A, Z = 2; (H3O)5[(Zr6BeCl12)Cl6].19H2O (4), cubic, Im3m, a = 13.8956(4) A, Z = 2; (H3O)5[(Zr6MnCl12)Cl6].19H2O (5), cubic, Im3m, a = 14.029(3) A, Z = 2; (H3O)4[(Zr6BCl12)Cl6].12.97H2O (6), tetragonal, P4(2)/mnm, a = 11.5373(2) A, c = 15.7169(4) A, Z = 2; (H3O)4[(Zr6BCl2)Br6].13.13H2O (7), tetragonal, P4(2)/mnm, a = 11.7288(6) A, c = 15.931(1) A, Z = 2.

H2NMe2]CuZrCl6: Hydrogen-Bond Induced Distortions in a Copper Zirconium Chloride Analogue of a Thiophosphate

The copper(I) zirconium(IV) halide, [H2NMe2]CuZrCl6 (1), has been synthesized, and its single-crystal X-ray structure was determined. The crystal undergoes a phase transition at −60 °C giving a room-temperature structure with a = 10.1105(6) A, b = 9.9463(5) A, c = 12.7254(8) A, β = 110.287(5)° in the monoclinic space group C2/c, Z = 4, and a low-temperature structure (−116 °C) with a = 10.234(2) A, b = 9.427(1) A, c = 12.691(2) A, β = 109.90(2)° in the monoclinic space group P21/c, Z = 4. [H2NMe2]CuZrCl6 is constructed from unique one-dimensional chains with zirconium and copper in alternating octahedral and tetrahedral coordination environments, respectively. The structural relationship between (CuCl4)3- and (PS4)3- is demonstrated by the analogy of this structure to that of KNiPS4. The phase transition, which occurs at approximately −60 °C, results in altered configurations of the dimethylammonium to metal−chloride hydrogen bonding. In addition, a remarkable distortion in the cuprous chloride tetrahedra...

Electrochemistry of Centered Hexanuclear Zirconium Halide Clusters in Ambient-Temperature Chloroaluminate Molten Salts.

Ambient temperature AlCl(3)-1-ethyl-3-methylimidazolium chloride (ImCl) molten salts, both basic (40/60 mol % AlCl(3)/ImCl) and acidic (60/40 mol % AlCl(3)/ImCl), were used in an electrochemical investigation of centered hexanuclear zirconium halide clusters. In the basic molten salt, these [(Zr(6)ZCl(12))Cl(6)](n-) (Z = Be, B, C, Mn, Fe) centered clusters exhibit the following electrochemical reactions on a glassy carbon electrode (potentials vs Al/Al(3+)): [(Zr(6)BeCl(12))Cl(6)](n)()(-) + e(-) right harpoon over left harpoon [(Zr(6)BeCl(12))Cl(6)](()(n)()(+1))(-), E(1/2) = -0.613 V (n = 4), E(1/2) = -1.085 V (n = 5); [(Zr(6)BCl(12))Cl(6)](n)()(-) + e(-) right harpoon over left harpoon [(Zr(6)BCl(12))Cl(6)](()(n)()(+1))(-), E(1/2) = -0.365 V (n = 4), E(1/2) = 0.072 V (n = 3); [(Zr(6)CCl(12))Cl(6)](n)()(-) + e(-) right harpoon over left harpoon [(Zr(6)CCl(12))Cl(6)](()(n)()(+1))(-), E(1/2) = 0.230 V (n = 3); [(Zr(6)MnCl(12))Cl(6)](4)(-) + e(-) right harpoon over left harpoon [(Zr(6)MnCl(12))Cl(6)](5)(-), E(1/2) = -0.432 V. In the acidic melt, only electrochemical reactions [(Zr(6)BeCl(12))(AlCl(4))(6)](n)()(-) + e(-) right harpoon over left harpoon [(Zr(6)BeCl(12))(AlCl(4))(6)](()(n)()(+1))(-), E(1/2) = -0.069 V (n = 5), E(1/2) = 0.504 V (n = 4), and [(Zr(6)BCl(12))(AlCl(4))(6)](4)(-) + e(-) right harpoon over left harpoon [(Zr(6)BCl(12))(AlCl(4))(6)](5)(-), E(1/2) = 0.700 V are clearly observed. These data is consistent with less systematic observations of oxidation of these clusters in solution. No unambiguous one-electron electrochemical reduction nor oxidation is observable for the Fe-centered cluster in the ionic liquids. The half-wave potentials of the above reactions of the Be-, B-, C-, and Mn-centered clusters are controlled largely by clusters' charges. This correlation of redox potentials allows a useful direct comparison with data for related hexanuclear niobium clusters in the literature.