Preferred Crystal Orientation Research Articles

Enhanced hydrogen evolution performance of Co/CoP in electrolysis of water by interfacial regulation of crystal plane orientation

Modulating the heterojunction interface is an effective way to improve the electrocatalytic efficiency of water electrolysis, and the metal centers with preferred crystal plane orientation offer the potential to enhance the interfacial charge transfer and electrode reaction kinetics. In this study, a Co/CoP modified hydrogen evolution electrode with selective exposure of the metal-centered Co(002) crystal face was prepared using a one-step electrodeposition method by adjusting the P/Co molar ratio. Results demonstrate that the preferential orientation of Co(002) crystal face in Co/CoP leads to an increased electrochemical active surface area, significantly reduced interfacial impedance and Tafel slope. Moreover, it brings the d-band center closer to the Fermi level, which is thermodynamically favorable for hydrogen evolution reaction (HER). Under optimized conditions, Co/CoP exhibits overpotentials of 85 mV and 183 mV at 10 mA cm−2 and 100 mA cm−2, respectively. After long-term and cyclic stability tests, no significant activity decay is observed, demonstrating excellent hydrogen evolution activity and cyclic stability.

Stabilizing Anode-Electrolyte Interface for Dendrite-Free Zn-Ion Batteries Through Orientational Plating with Zinc Aspartate Additive.

The stability of aqueous Zn-ion batteries (AZIBs) is detrimentally influenced by the formation of Zn dendrites and the occurrence of parasitic side reactions at the Zn metal anode (ZMA)-electrolyte interface. The strategic manipulation of the preferential crystal orientation during Zn2+ plating serves as an essential approach to mitigate this issue. Here, Zn aspartate (Zn-Asp), an electrolyte additive for AZIBs, is introduced not only to optimize the solvation structure of Zn2+ , but also to crucially promote preferential Zn2+ plating on the (002) crystal plane of ZMA. As a result, both side reactions and Zn dendrites are effectively inhibited, ensuring an anode surface free of both dendrites and by-products. The implementation of Zn-Asp leads to significant enhancements in both Zn||Zn symmetric and Zn||Ti batteries, which demonstrate robust cyclability of over 3200h and high Coulombic efficiency of 99.29%, respectively. Additionally, the Zn||NaV3 O8 ·1.5H2 O full battery exhibits remarkable rate capability, realizing a high capacity of 240.77mAhg-1 at 5Ag-1 , and retains 92.7% of its initial capacity after 1000 cycles. This research underscores the vital role of electrolyte additives in regulating the preferential crystal orientation of ZMA, thereby contributing to the development of high-performing AZIBs.

Formation of cube-on-face texture {0 0 1}〈uv0〉 in a high saturation soft magnetic iron-cobalt-vanadium alloy by controlled phase-transformation γ → α

In this investigation, the soft magnetic properties of a high saturation iron-cobalt-vanadium alloy with 17 wt% Co and 1.5 wt% V have been greatly enhanced by a special heat treatment in the γ-region, which effectively leads to the formation of a magnetically favorable strong cube-on-face texture during cooling. Based on EBSD analyses, a high degree of cube-on-face texture {001}〈uv0〉 of up to 80 % was obtained. The underlying mechanism is presumed to be a preferred surface nucleation of {001}-grains during cooling through the two-phase-region α + γ. The annealing of all samples was performed in ceramic powder. Therefore, mechanical stress is not considered the primary cause for this preferred nucleation, which should simplify the upscaling to an industrial process. As the 〈100〉 direction is the magnetic easy axis in this material system, this preferred crystal orientation goes along with very good soft magnetic properties such as a high maximum permeability µmax of 16,000, an increased induction B(160 A/cm) of 2.14 T and a reduced coercivity Hc of about 30 A/m. The core loss is reduced for frequencies up to 1 kHz. This favorable combination of properties, along with the reduced Co content, opens up new possibilities for the use of this material in electrical machines with both a high efficiency and a high power density.

Rational catalyst structural design to facilitate reversible Li-CO2 batteries with boosted CO2 conversion kinetics

Lithium-CO2 batteries (LCBs) are regarded as a promising energy system for CO2 drawdown and energy storage capability which has attracted widespread interest in carbon neutrality and sustainable societal development. However, their practical application has been limited by slow kinetics in catalytic reactions and poor reversibility of Li2CO3 products which leads to the issue of a large overpotential, low energy efficiency and poor reversibility. Herein, an efficient catalyst design and synthesis strategy is proposed to overcome the abovementioned bottleneck. Through an electrical joule heating procedure, Pt with random crystal orientations is converted into a 3D porous Pt catalyst with preferred (111) crystal orientation within seconds, exhibiting enhanced CO2 conversion kinetics with superior electrochemical performance. This includes ultralow overpotential (0.45 V), fast rate charging (up to 160 µA cm−2) and high stability (over 200 cycles under 40 µA cm−2). A proof-of-concept stacked Li-CO2 pouch cell, with stable operation under practical current density is demonstrated, indicating significant potential for large-scale operations. This bottom-up design of efficient catalysts and synthesis strategy offers a rapid and cost-effective approach to maximizing catalytic sites for CO2 conversion under restricted catalyst loading, showcasing its versatility across a broad spectrum of catalyst-based energy conversion and storage systems.

Directing (110) Oriented Lithium Deposition through High-flux Solid Electrolyte Interphase for Dendrite-free Lithium Metal Batteries.

Controlling lithium (Li) electrocrystallization with preferred orientation is a promising strategy to realize highly reversible Li metal batteries (LMBs) but lack of facile regulation methods. Herein, we report a high-flux solid electrolyte interphase (SEI) strategy to direct (110) preferred Li deposition even on (200)-orientated Li substrate. Bravais rule and Curie-Wulff principle are expanded in Li electrocrystallization process to decouple the relationship between SEI engineering and preferred crystal orientation. Multi-spectroscopic techniques combined with dynamics analysis reveal that the high-flux CF3 Si(CH3 )3 (F3 ) induced SEI (F3 -SEI) with high LiF and -Si(CH3 )3 contents can ingeniously accelerate Li+ transport dynamics and ensure the sufficient Li+ concentration below SEI to direct Li (110) orientation. The induced Li (110) can in turn further promote the surface migration of Li atoms to avoid tip aggregation, resulting in a planar, dendrite-free morphology of Li. As a result, our F3 -SEI enables ultra-long stability of Li||Li symmetrical cells for more than 336 days. Furthermore, F3 -SEI modified Li can significantly enhance the cycle life of Li||LiFePO4 and Li||NCM811 coin and pouch full cells in practical conditions. Our crystallographic strategy for Li dendrite suppression paves a path to achieve reliable LMBs and may provide guidance for the preferred orientation of other metal crystals.

Directing (110) Oriented Lithium Deposition through High‐flux Solid Electrolyte Interphase for Dendrite‐free Lithium Metal Batteries

AbstractControlling lithium (Li) electrocrystallization with preferred orientation is a promising strategy to realize highly reversible Li metal batteries (LMBs) but lack of facile regulation methods. Herein, we report a high‐flux solid electrolyte interphase (SEI) strategy to direct (110) preferred Li deposition even on (200)‐orientated Li substrate. Bravais rule and Curie‐Wulff principle are expanded in Li electrocrystallization process to decouple the relationship between SEI engineering and preferred crystal orientation. Multi‐spectroscopic techniques combined with dynamics analysis reveal that the high‐flux CF3Si(CH3)3 (F3) induced SEI (F3‐SEI) with high LiF and −Si(CH3)3 contents can ingeniously accelerate Li+ transport dynamics and ensure the sufficient Li+ concentration below SEI to direct Li (110) orientation. The induced Li (110) can in turn further promote the surface migration of Li atoms to avoid tip aggregation, resulting in a planar, dendrite‐free morphology of Li. As a result, our F3‐SEI enables ultra‐long stability of Li||Li symmetrical cells for more than 336 days. Furthermore, F3‐SEI modified Li can significantly enhance the cycle life of Li||LiFePO4 and Li||NCM811 coin and pouch full cells in practical conditions. Our crystallographic strategy for Li dendrite suppression paves a path to achieve reliable LMBs and may provide guidance for the preferred orientation of other metal crystals.

High Thermal Conductivity and Low Dielectric Constant of Polyesters Based on Fluorine and Mesogenic Unit

AbstractHigh thermal conductivity polymeric dielectrics with advanced dielectric properties are urgently demanded in various applications. In this study, a series of thermoplastic polyesters containing different content of fluorine and mesogenic unit in main chains are synthesized utilizing polycondensation. The preferred orientation of liquid crystal can effectively inhibit phonon scattering, and the introduction of fluorine can reduce the polarizability of the polymer and increase the free volume. By introducing the biphenyl mesogenic unit and fluorine into the main chain, its thermal conductivity has been increased to 0.425 Wm−1k−1 from 0.183 Wm−1k−1(the polymer without liquid crystal element), which is 132% higher than that of the liquid crystal polymer without fluorine. In addition, the dielectric constant of polyester decreased to 2.97, and the dielectric loss drops to 8.74 × 10−4. The influence mechanism of two ways on its thermal and dielectric properties is explored. Good thermal conductivity and excellent dielectric properties make potential in the thermal management system and flexible electronics.

H13 tool steel fabricated by wire arc additive manufacturing: Solidification mode, microstructure evolution mechanism and mechanical properties

The critical application value of AISI H13 tool steel in the die and mold industry and the great application potential of additive manufacturing (AM) technology in die manufacturing and repair have attracted extensive attention from researchers. However, there is no consensus on the solidification mode and microstructure evolution mechanism of H13 during AM. The relationship between the unique cellular/dendritic substructures and the grain structures in AM-fabricated H13 components has yet to be fully understood. This work focused on the microstructure and mechanical properties of different regions of the H13 component manufactured by wire arc additive manufacturing technology. Thermodynamic calculations and experimental results confirmed the formation of δ-ferrite during the non-equilibrium solidification of AM. The cellular/dendritic substructure is caused by the solidification of δ-ferrite and austenite together with the accompanying segregation. The results of optical microscopy and scanning electron microscopy, as well as the reconstructed prior austenite grain structure by electron backscatter diffraction (EBSD) all confirmed that the formation and distribution of cellular/dendritic substructures were not directly related to the prior austenite grain. The EBSD pole figures show that although the martensite transformation weakened the preferred orientation of crystals, the martensite phase in the typical structure of the deposition area still had a high texture strength, which may be the main reason for the anisotropic mechanical properties of the H13 component.

Vapor transport deposited Sb2(S,Se)3 thin film: Effect of deposition temperature and Sb2S3/Sb2Se3 mass ratio

The vapor transport deposition (VTD) processing is an effective and low-cost techniques to fabricate antimony selenosulfide (Sb2(S,Se)3) photovoltaic materials with large grains and preferred crystal orientations. Currently, the influences of various single deposition conditions of VTD on performances of Sb2(S,Se)3 solar cells have been studied, but which parameter should be optimized and how it affects is a noteworthy issue. Herein, the effects of two important deposition parameters, deposition temperature and mass ratio of Sb2S3/Sb2Se3 on the structure and photo-electrochemical properties of Sb2(S,Se)3 were investigated, and the mechanism of their impact on the growth of thin film was also discussed. It found that the (hk1) orientation growth of Sb2(S,Se)3 was dominated by Sb-Se bonds at deposition temperatures ranging from 460 °C to 500 °C. As the temperature increased, the S content in the film decreased. When the deposition temperature was fixed at 480 °C, it was found that the effect of the mass ratio of Sb2S3/Sb2Se3 on the growth was more about adjusting the concentration of Se than increasing the bonding of Sb-S. The introduced S can make the film smooth and dense, and also induce the growth of film in the (hk1) orientation when mass ratio is coupled with deposition temperature. Furthermore, the results of photo-electrochemical measurement indicated that photocurrent density is related to S content and preferred orientation. By adjusting the mass ratio, flat Sb2(S,Se)3 films were obtained with band gaps ranging from 1.24 eV to 1.42 eV and carrier concentrations ranging from 9.62 × 1014 cm−3 to 1.62 × 1015 cm−3, exhibiting good absorption layer characteristics.

On the surface biasing effectiveness during reactive high-power impulse magnetron sputter deposition of zirconium dioxide

In this study, we investigate the effect of surface biasing during high-power impulse magnetron sputter deposition of non-conductive zirconium dioxide films on substrates with different capacitances. We employ reactive high-power impulse magnetron sputtering to deposit ZrO2 films using a circular Zr target in a pure oxygen atmosphere. The deposition experiments are conducted on two types of substrates: high-capacitance (thin thermally grown SiO2 on Si) and low-capacitance (soda-lime glass). By varying the time shift between the target voltage pulse and the negative substrate bias voltage pulse, we analyze the impact on the preferred crystal orientation of the deposited ZrO2 films and the deposition rate. We measure the current and voltage waveforms during the deposition process and utilize a surface charging model to understand the charging behavior of the growing film. Additionally, time- and energy-resolved ion mass spectra are measured to gain insights into the ion behavior during film growth. Our results demonstrate that energetic ion bombardment and appropriate timing of substrate biasing can influence the crystal orientation of ZrO2 films, favouring specific orientations over others. We also explain the different behavior observed on low- and high-capacitance substrates.

Diffusion mechanisms between La2SiO5 and SiO2 during formation of textured lanthanum silicate oxyapatite crystals

Lanthanum silicate oxyapatite (LSO) is a promising alternative electrolyte for solid oxide fuel cell (SOFC) applications. They exhibit anisotropic oxide-ionic conduction; therefore, a preferential crystal orientation along the c-axis is necessary to achieve optimal conductivity. This study is performed to understand the reaction mechanisms involved in the formation of an LSO layer at the interface of the La2SiO5/SiO2 diffusion pair during reactive sintering at high temperatures. Different La2SiO5/SiO2 bilayers were fabricated in sandwich-type structures using silica-type quartz or La2SiO5 supports obtained via electrophoresis and uniaxial pressing, respectively. These supports were pre-sintered and then coated with a suspension of the opposite component. The diffusion pairs were isothermally heated at 1500 °C at different holding times (10, 20, and 40 h) and at 1600 °C for 10 h. Their surfaces and cross-sections were investigated via X-ray diffraction, scanning electron microscopy (SEM) observations, energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy.Experimental results show that two different driving forces were involved in the nucleation and growth of apatite crystals. The first is the chemical potential gradient in lanthanum between the components of the layers, and the second is the electric field created to preserve the electroneutrality of the system. The predominant diffusing species in this bilayer system were La+III and O-II, and their diffusion is enhanced by the formation of a glassy phase on the silica grains through the transformation of silica-type quartz into cristobalite. The formation of a La2Si2O7 intermediate phase was detected, which is vital to the interdiffusion of species and the nucleation and growth of oriented apatite crystals. The porosity gradient observed in the cross-section after reactive diffusion suggests the possibility of achieving an SOFC half-cell device via this process.

The Origin and Evolution of DMM-Like Lithospheric Mantle Beneath Continents: Mantle Xenoliths from the Oku Volcanic Group in the Cameroon Volcanic Line, West Africa

Abstract The lithospheric mantle as sampled by peridotite xenoliths in some continental settings resembles the source of mid-ocean ridge basalts (MORB). Whether this resemblance is a primary feature or the result of post-formation secondary processes remains controversial. Here, the age, origin and thermochemical evolution of fertile continental mantle are constrained based on the chemical composition of minerals in spinel-facies lherzolite and websterite xenoliths from the Wum maar and Befang cinder cone of the Oku Volcanic Group (Cameroon Volcanic Line, West Africa), combined with in-situ Sr isotope compositions of clinopyroxene and fabric investigation by Electron Backscatter Diffraction (EBSD). The majority of lherzolites (here assigned to Group I) consist of minerals with fertile composition (olivine Fo89, Al-rich pyroxenes, spinel Cr# 0.08–0.10). Clinopyroxene is LREE-depleted and has depleted 87Sr/86Sr (0.7017–0.7020). Crystal-preferred orientation determined by EBSD reveals that clinopyroxene, and sporadically both clino- and orthopyroxene, post-date the olivine framework. Subordinate Group II lherzolites also contain secondary clinopyroxene which is LREE-enriched and has higher 87Sr/86Sr (0.7033). In contrast, the scarce lherzolites of Group III are more refractory: they contain 72–78 vol.% olivine, Al-poor pyroxenes, and spinel with Cr# 0.18. Clinopyroxene (87Sr/86Sr 0.7021) is texturally coeval with olivine and orthopyroxene. Few lherzolites contain amphibole (87Sr/86Sr 0.7031) which post-dates the nominally anhydrous minerals. Most of the websterites (Group A) are aluminous (spinel Cr# 0.04–0.06) with LREE-depleted clinopyroxene having depleted 87Sr/86Sr ratios (0.7017–0.7020) similar to Group I lherzolites. Chemical characteristics of minerals coupled with the crystal-preferred orientation data suggests that Group I lherzolites originated in the spinel stability field by reactive intergranular percolation of an incompatible element-depleted MORB-like melt. Group A websterites likely formed as cumulates from that melt. The Group II lherzolites supposedly occur close to lithosphere-asthenosphere boundary and record interaction with lavas of the Cameroon Volcanic Line, whereas Group III lherzolites occur in the shallow part of the mantle profile and represent the protolith from which the Group I lherzolites were formed. Local crystallization of amphibole and concomitant recrystallization of the host lherzolite were driven by supply of water in an event post-dating the formation of LREE-depleted rejuvenated rocks. Migration of alkaline melts of the CVL apparently did not significantly affect the mineral and chemical composition of the lithospheric mantle, which allowed Group I lherzolites and Group A websterites to retain very low 87Rb/86Sr (average 0.002) and depleted 87Sr/86Sr ratios in clinopyroxene. This not only indicates their formation in the Paleoproterozoic (~2.0–2.25 Ga), possibly during the Eburnean orogeny at the margin of the Congo craton, but also indicates surprisingly little influence of the regionally recognized Pan-African event.

Multistage formation of the titanite-centered ocellar texture in magma mixing zones: New insights from field, petrographic and mineralogic evidence in the Paleoproterozoic Mineiro belt, Brazil

The titanite-centered ocellar texture is among the rarest and most intriguing textures associated with magma hybridization zones in plutonic environments. In order to contribute to the discussion regarding its formation process and relation to mixing, we investigated detailed field, petrographic, and mineralogical aspects of two occurrences of ocellar hybrid rocks associated with the Paleoproterozoic Macuco de Minas metagranitoid, Mineiro belt, southern São Francisco Craton. The studied rocks display oriented elliptic leucocratic aggregates composed of quartz, oligoclase (An15-20), microcline, apatite, and zircon, with an up-to centimetric poikilitic or euhedral diamond-shaped titanite crystals in their center (ocelli). The ocelli are often partially connected and immersed in a mesocratic tonalitic matrix composed of quartz, oligoclase (An15-20), Fe-biotite, titanite, allanite, fluorapatite, and zircon. The titanite crystals in the ocelli are enriched in Ti, LREE, Y, Th, and Zr and depleted in Al and F compared to the ones from the matrix, indicating that these compose two distinct groups of titanite. We propose that the development of the titanite-centered ocellar texture is a multi-stage interaction between mafic and felsic end-members, in which a biotite-rich tonalitic hybrid mush is injected by a fractionated leucogranitic melt. The leucogranitic melt migrates through veins that follow the preferred orientation of crystals in the hybrid mush and becomes enriched in Ti by the destabilization of biotite, resulting in the crystallization of the euhedral diamond-shaped titanite crystals. The veins are then disrupted, turning into elliptic ocelli in response to the pressure applied by the denser hybrid mush.

Mixing Dion–Jacobson and Ruddlesden–Popper Structures in Quasi‐2D Perovskite Films for Thermal‐ and Photo‐Stable Stimulated Emission

AbstractQuasi‐two–dimensional (2D) perovskite films are promising candidates as a gain medium for stimulated emission owing to their hydrophobicity and efficient energy funneling that facilitates the population inversion. However, the commonly used Ruddlesden–Popper (R–P) perovskites still suffer from instability induced by high‐density pumping as well as the resulting heating effect. Here, quasi‐2D perovskite films with mixed Dion–Jacobson (D–J) and R–P phases are demonstrated with both excellent amplified spontaneous emission (ASE) properties and thermal‐ and photo‐stabilities under ambient conditions. In these films, octyl ammonium bulky organic cations are used to obtain the preferred crystal orientation and highly smooth surface for low‐threshold ASE, while 1,8‐octanedi ammonium cations contribute to the greatly improved stability. The films containing the D–J phase exhibit good structural stability even after 130 °C heat treatment for 48 h. The mixed‐ligands film maintains a low ASE threshold of 11.6 µJ cm−2 and a high optical gain of 413 cm−1 after environmental annealing. It is demonstrated that it is the diammonium that firmly bonds to the perovskite layer,allowing the maintenance of quasi‐2D perovskite structure and good ASE performances.

Effect of heat input on the microstructure and mechanical properties of the deposition obtained by selective laser melting (SLM) of precipitation hardened martensitic stainless steel

The additive manufacturing (AM) shows a great market prospect in the closed-impeller for the centrifugal compressor. In the paper, the precipitation hardened martensitic stainless steel (PHMSS) deposition with different heat input parameters by the selective laser melting (SLM) and the micro-Vickers hardness, tensile strength and impact toughness were detected respectively. The evolution laws of microstructure were analyzed by the SEM, TEM, EDS and EBSD. The tensile strength of the deposition with heat input of the 4.21 J/cm were best and the strength along the build surface direction (X and Y) and the build height direction (Z) were 1193.3 MPa、1222.1 MPa、1159.8 MPa respectively. The impact toughness of the deposition were lower than that of base metas and the tonghness between the sureface direction and the bulid heght direction was anisotropy. The crystals showed a conlumanr pattern along the Z direction and with the increase the heat input, the preferred orientation along the Z changed from the preferred crystal plane and crystal orientation to the pure preferred crystal orientation. A large amount of Cr3C2 phase is precipitated and its size increased with the increase of heat input. The above research results normalize the influence of each parameter during the AM on the microstructure and mechanical properties of the deposition to the heat input, which is helpful to simplify the optimization of the procedure specification and promote its industrial application.

Si–Sn codoped n-GaN film sputtering grown on an amorphous glass substrate

DC-pulse magnetron sputtering was utilized to deposit a 300 nm-thick n-type GaN thin film that was co-doped with Si–Sn onto an amorphous glass substrate with a ZnO buffer layer. The deposited thin films were then subjected to post-growth thermal annealing at temperatures of 300 °C, 400 °C, or 500 °C to enhance their crystal quality. Hall measurements revealed that the film annealed at 500 °C had the lowest thin-film resistance of 0.82 Ω cm and the highest carrier concentration of 3.84 × 1019 cm−3. The thin film surface was studied using atomic force microscopy; the film annealed at 500 °C had an average grain size and surface roughness of 25.3 and 2.37 nm, respectively. Furthermore, the x-ray diffraction measurements revealed a preferential (002) crystal orientation and hexagonal wurtzite crystal structure at 2θ ≈ 34.5°. The thin film had a full width at half maximum value of 0.387°, it was also found to be very narrow. Compositional analysis of the films was conducted with x-ray photoelectron spectroscopy and verified that both Si and Sn were doped into the GaN film utilizing covalent bonding with N atoms. Finally, the film annealed at 500 °C had a high optical transmittance of 82.9% at 400–800 nm, a high figure of merit factor of 490.3 × 10−3 Ω−1, and low contact resistance of 567 Ω; these excellent optoelectronic properties were attributed to the film’s high electron concentration and indicate that the material is feasible for application in transparent optoelectronic devices.

Direct-Patterning ZnO Deposition by Atomic-Layer Additive Manufacturing Using a Safe and Economical Precursor.

Area-selective atomic layer deposition (AS-ALD) is a bottom-up nanofabrication method delivering single atoms from a molecular precursor. AS-ALD enables self-aligned fabrication and outperforms lithography in terms of cost, resistance, and equipment prerequisites, but it requires pre-patterned substrates and is limited by insufficient selectivity and finite choice of substrates. These challenges are circumvented by direct patterning with atomic-layer additive manufacturing (ALAM) - a transfer of 3D-printing principles to atomic-layer manufacturing where a precursor supply nozzle enables direct patterning instead of blanket coating. The reduced precursor vapor consumption in ALAM as compared with ALD calls for the use of less volatile precursors by replacing diethylzinc used traditionally in ALD with bis(dimethylaminopropyl)zinc, Zn(DMP)2 . The behavior of this novel ZnO ALAM process follows that of the corresponding ALD in terms of deposit quality and growth characteristics. The temperature window for self-limiting growth of stoichiometric, crystalline material is 200-250°C. The growth rates are 0.9Å per cycle in ALD (determined by spectroscopic ellipsometry) and 1.1Å per pass in ALAM (imaging ellipsometry). The preferential crystal orientation increases with temperature, while energy-dispersive X-ray spectroscopic and XPS show that only intermediate temperatures deliver stoichiometric ZnO. A functional thin-film transistor is created from an ALAM-deposited ZnO line and characterized.

PZT Composite Film Preparation and Characterization Using a Method of Sol-Gel and Electrohydrodynamic Jet Printing.

Lead zircon titanate (PZT) composite films were advantageously prepared by a novel hybrid method of sol-gel and electrohydrodynamic jet (E-jet) printing. PZT thin films with thicknesses of 362 nm, 725 nm and 1092 nm were prepared on Ti/Pt bottom electrode via Sol-gel method, and then the PZT thick films were printed on the base of the PZT thin films via E-jet printing to form PZT composite films. The physical structure and electrical properties of the PZT composite films were characterized. The experimental results showed that, compared with PZT thick films prepared via single E-jet printing method, PZT composite films had fewer micro-pore defects. Moreover, the better bonding with upper and lower electrodes and higher preferred orientation of crystals were examined. The piezoelectric properties, dielectric properties and leakage currents of the PZT composite films were obviously improved. The maximum piezoelectric constant of the PZT composite film with a thickness of 725 nm was 69.4 pC/N, the maximum relative dielectric constant was 827 and the leakage current was reduced to 1.5 × 10-6A at a test voltage of 200V. This hybrid method can be widely useful to print PZT composite films for the application of micro-nano devices.

Microstructural engineering of zeolite membranes through composite seed layers

MFI membranes were synthesized using composite seeds consisting of zeolite nanocrystals and amorphous silica nanoparticles. The weight compositions of zeolite and silica particles were tuned to 100/0, 75/25, 50/50, and 25/75, respectively, which were then deposited as seed layers on porous alumina support through rubbing. At the seeded growth condition at 135 °C for 24 h, the film thickness of zeolite membranes grown from 4 different seed layers was similar to 3 μm, along with preferential crystal orientation to (h 0 h) direction. The upper parts of the zeolite membrane shared comparable film characteristics independent of seed composition, according to FCOM images of the MFI membranes. On the other hand, the zeolite membrane prepared from a seed layer of 75 wt% zeolite and 25 wt% silica particles had the greatest N2/SF6 gas selectivity of >175 and N2 gas permeance of >3300 GPU. Porosimetry also showed that there are fewer non-zeolite pathways in the zeolite membrane. Such results were attributed to differences in silica loading in the seed layer, where the silica species effectively altered the microstructure of zeolite membranes. The grain size of zeolite membranes increases as silica particle loading increases, reducing the chance of non-zeolitic defects occurring at grain boundaries. The composite seed with a silica loading of 25% was particularly successful because it did not inhibit the intergrowth of zeolite seed crystals while sacrificing slight N2 gas permanence. Thus, adding silica nanoparticles to the seed layer can help reduce non-zeolite defects in MFI membranes, according to this research. Further research is needed to prove that this method can be applied to zeolite membranes with other zeolite frameworks.

Accelerated Sequential Deposition Reaction via Crystal Orientation Engineering for Low‐Temperature, High‐Efficiency Carbon‐Electrode CsPbBr3 Solar Cells

Low‐temperature, ambient processing of high‐quality CsPbBr3 films is demanded for scalable production of efficient, low‐cost carbon‐electrode perovskite solar cells (PSCs). Herein, we demonstrate a crystal orientation engineering strategy of PbBr2 precursor film to accelerate its reaction with CsBr precursor during two‐step sequential deposition of CsPbBr3 films. Such a novel strategy is proceeded by adding CsBr species into PbBr2 precursor, which can tailor the preferred crystal orientation of PbBr2 film from [020] into [031], with CsBr additive staying in the film as CsPb2Br5 phase. Theoretical calculations show that the reaction energy barrier of (031) planes of PbBr2 with CsBr is lower about 2.28 eV than that of (020) planes. Therefore, CsPbBr3 films with full coverage, high purity, high crystallinity, micro‐sized grains can be obtained at a low temperature of 150 °C. Carbon‐electrode PSCs with these desired CsPbBr3 films yield the record‐high efficiency of 10.27% coupled with excellent operation stability. Meanwhile, the 1 cm2 area one with the superior efficiency of 8.00% as well as the flexible one with the champion efficiency of 8.27% and excellent mechanical bending characteristics are also achieved.