Thin Films Research Articles

Modeling monocular form deprivation in rabbits using a simulated-cataract intraocular lens

AIM: To establish an animal model of form deprivation amblyopia based on a simulated cataract intraocular lens (IOLs). METHODS: Poly(dimethyl siloxane)-SiO2 thin films (PSF) with different degrees of opacity as IOL materials were prepared. The light transmission of the PSF-IOL was measured, and its in vitro biosafety was determined by cell counting kit (CCK)-8 assay using the HLEC-B3 cell line and ARPE-19 cell line. Subsequently, the in vivo safety was determined by implanting the PSF-IOL with 10% wt SiO2 into the right eyes of New Zealand white rabbits (PSF-IOL group), and compared with two control groups: contralateral comparison group and normal control (NC) group (Contralateral comparison group: the fellow eye; NC group: a group of binocular normal rabbits without intervention). The flash visual-evoked potentials (F-VEPs) were measured to verify amblyopia. RESULTS: PSFs containing 0, 2%, and 10% wt SiO2 were successfully constructed. The 0 SiO2 PSF was transparent, while the 10% wt SiO2 PSF was completely opaque. It was found that PSF did not induce unwanted cytotoxicity in HLECs and ARPE19 cells in vitro. In vitro, PSF-IOL with 10% wt SiO2 was also non-toxic, and no significant inflammation or structural changes occurred after four weeks of PSF-IOL implantation. Finally, our IOL-simulated congenital cataract rabbit detected by F-VEPs suggested tentative amblyopia. CONCLUSION: A PSF-IOL that mimics cataracts is created. A novel form deprivation model is created by the IOL-simulated congenital cataract rabbit. It can be developed fast and stable and holds great potential for future study.

Assessing the combined effects of chemical and mechanical parameters on silar-grown nanostructured ZnO thin films

In the literature, a comprehensive assessment of the combined impacts of chemical and mechanical parameters on the properties of thin films grown by SILAR is missing. In this work, ZnO film formation is investigated under variable precursor concentration, pH, withdrawal speed and number of cycles. Interestingly, the produced ZnO films displayed remarkable aspect ratio and morphological variability, ranging from the commonly obtained nanograins shape towards hexagonal nanorods, flower- like rods and nanoneedles, which to our knowledge have not yet been achieved by using single step SILAR process. More particularly, low concentration and intermediate pH and withdrawal rates were favorable for nanorods formation. In addition, increasing the withdrawal speed from 26 to 30 cm·min-1 resulted in a thinner film with improved rod uniformity and reduced crystallite size. This is the first study on the impact of substrate withdrawal speed on SILAR films. Among all studied parameters, the number of cycles was particularly useful for tuning film thickness, while preserving its target shape. In addition, the films grown under a higher number of cycles showed improved film crystallinity and rod orientation with reduced dislocation density, microstrain and bandgap energy. In our conditions, the most suitable combination of parameters required for exhibiting optimized nanorod-shaped coating are: a concentration of 0.07 M, pH of 10.5, speed of 30 cm·min-1 and 40 cycles. In this case, XRD, XPS, Raman and FTIR spectra displayed typical features of hexagonal Wurtzite structure of ZnO with no impurities within the film surface, whereas AFM measured a thickness of 1.4 μm with 243 nm surface roughness.

Excimer formation in zinc-phthalocyanine revealed using ultrafast electron diffraction

The formation of excited dimer states, so called excimers, is an important phenomenon in many organic molecular semiconductor solid state aggregates. In contrast to Frenkel exciton-polarons, an excimer is long-lived and energetically low-lying due to stabilization resulting from a substantial reorganization of the intermolecular geometry. Here, we show that ultrafast electron diffraction can follow the dynamics of solid-state excimer formation in polycrystalline thin films of a molecular semiconductor, revealing both the key reaction modes and the eventual structure of the emitting state. We study the prototypical organic semiconductor zinc-phthalocyanine (ZnPc) in its crystallographic α-phase as a model excimeric system. We show that the excimer forms in a two-step process starting with a fast dimerization (approx. 0.4 ps) followed by a subsequent slow shear-twist motion (14 ps) leading to an alignment of the π-systems of the involved monomers. This structural distortion persists well beyond 300 ps. Furthermore, we show that while the same excimer geometry is present in partially fluorinated derivatives of ZnPc, the formation kinematics slow down with increasing level of fluorination.

Nanostructured bismuth chloride based ((CH3NH3)3Bi2IxCl9-x) active layers for lead-free perovskite solar cells

Abstract Bismuth is one of the promising elements that can replace toxic lead in perovskite solar cells. However, surface roughness and inhomogeneous morphology with voids on the bismuth perovskite films limits their photovoltaic performance. In the present work, a scalable doctor-blade technique is employed to prepare perovskite thin film with high surface coverage. Methylammonium bismuth halide (MABiH) ((CH3NH3)3Bi2ClxI9-x) nanoparticles were synthesized by conventional sol-gel technique. The formation of perovskite structure was confirmed by X-ray diffraction measurement which confirmed that MABiH perovskite films were in hexagonal symmetry with polycrystalline nature. The prepared perovskite nanoparticles were deposited on mesoporous TiO2-coated FTO substrates through the spin coating technique and doctor blade method. Morphology analysis of MABiH perovskite revealed the formation of an orange Lily-like structure with higher surface coverage. Lead-free mesoporous perovskite solar cells prepared using MABiH perovskite material with carbon as hole extraction layer showed a maximum power conversion efficiency (PCE) of 0.004 %, with short circuit current density of 89 μA/cm2, open circuit voltage of 0.12 V and fill factor of 38 %. These results allow us to step toward fabricating bulk MABiH lead-free perovskite solar cells.

Performance Analysis and Characterization of Natural Dye-sensitized Solar Cells (DSSCs) of Titanium Oxide (TiO2) Thin Film

Dye-sensitized solar cells (DSSCs) thin films of titanium oxide (TiO2) sensitized with the dyes of the almond and copper leaves extracted using ethanol and water (AE, AW, CE and CW) each, have been successfully deposited on FTO conductive glass substrate using the Dr Blading method. The deposited TiO2-DSSC thin films were subjected to UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy and I-V characteristics analysis to determine their optical, structural, morphological properties and solar cell parameters respectively. The results of the analysis showed that copper leaves dye-sensitized films (CE and CW) has absorbance is in the range of 0.45 to 0.9 and 0.25 to 0.45 respectively within the visible (VIS) regions. The absorbance of the films sensitized with almond leaves dye is lower in the range of 0.15 - 0.25 for AE and 0.04 – 0.09 for AW within the region. The percentage transmittance of the films was found to be in the range of 82.5% – 90% for the film AW, 35% – 55% for CW while the film AE has the lowest value of the order 12.5% - 35% within the VIS region. The reflectance percent of the films were generally low with the film CE having the highest value in the range of 27%-43%, CW in the range 17.5% - 26%, AE in the range 10% - 15%, while the film AW has values in the range 2.5% - 5.5% within the VIS region. All the deposited DSSCs films have high refractive index values throughout the VIS region. The bandgap energy values obtained for the films are 2.5 eV for film CE, 2.6 eV for CW, and 2.4 eV for the films AE and AW each. These are in the range of wide bandgap energies and are favourable for application in the device that required high temperature and fabrication of blue LEDs. The results of the structural analysis on the deposited thin films showed that both the films exhibited crystalline structure with crystallite sizes of 24.55 nm for CE, 27.68 nm for CW, 22.27 for AE and 36.30 for AW films. The films have low cell conversion efficiency but still within the margin of error for most DSSCs materials.

Low temperature catalytic growth graphene with V2O5 prepared with the oxidation method and its application in optoelectronic devices

Based on our previous research on the phase transition property of non-metallic vanadium oxide for low-temperature catalytic growth of graphene, we further propose that V thin films can be deposited by sputtering and then V2O5 thin films can be prepared by oxidizing the V thin films at 400 °C in a rapid annealing furnace with oxygen, which has a better crystalline structure and surface than the V2O5 thin films directly deposited by sputtering. The V2O5 prepared by oxidation was used to catalyze the growth of graphene at 300 °C in a PECVD furnace. During the growth process, a 10-fold increase in the H2 flow rate (200 sccm) was used to repair and eliminate the suspension bonds and defects of graphene, and the quality of graphene films was improved. Due to the high resistivity of V2O5 at room temperature, V2O5 can be directly used as the interlayer of the device, and the graphene-V2O5-Si (GVS) structure photodetector is proposed, which avoids the damage and impact of the transfer process and catalytic layer removal process in the conventional graphene device process. Additionally, because of the negative temperature coefficient of resistance (TCR) of vanadium oxide materials, the optical response of the GVS device is further extended to 1550 nm.

Alloying Ga2O3 with Fe2O3 on Corundum‐Structured rh‐ITO by Mist CVD and Its Demonstration of Photodetector and Photoelectrode Applications

Corundum‐structured α‐Ga2O3 is an ultrawide bandgap semiconductor with a bandgap of 5.3 eV and is actively investigated for applications in power electronics and optoelectronic devices. This study explores bandgap engineering of α‐Ga2O3 to broaden its application field. By alloying α‐Fe2O3, which has the same corundum structure as α‐Ga2O3, the bandgap can be tuned from 2.2 to 5.3 eV. This allows α‐Ga2O3 to be used as a visible‐light‐driven photocatalyst by narrowing its bandgap. Herein, (Ga, Fe)2O3 alloy thin films are grown on corundum‐structured indium tin oxide (rh‐ITO) electrodes for photocatalytic applications. X‐ray diffraction 2θ–ω measurements reveal that corundum‐structured α‐(Ga, Fe)2O3 thin films are grown on rh‐ITO electrodes with up to ≈20% Ga composition. At higher Ga compositions, orthorhombic ε‐GaFeO3 and amorphous Ga2O3 are observed on the rh‐ITO electrode. Photoresponsivity measurements using a photodetector structure confirm that the thin films exhibit visible light sensitivity upon alloying Fe2O3 with Ga2O3. Linear sweep voltammetry measurements indicate that the α‐(Ga, Fe)2O3 thin film grown on rh‐ITO can serve as a visible light‐driven photoelectrode. The findings contribute to the bandgap engineering of α‐Ga2O3 and its application in photocatalysis.

Optical, structural, and vibrational properties of In2S3 thin films by Sputtering-RF for applications in optoelectronics devices.

Abstract Experimental results on the crystalline orientation properties, energy band gap, and Raman vibrational modes of Indium Sulfide (In2S3) thin films grown by Sputtering in Radio Frequency mode are presented. The In2S3 thin films were grown at 25, 200, and 300°C; thereafter the samples were thermally annealed in air for 30 min at 450°C, in order to improve their crystalline and physical properties. Energy dispersive X-ray spectroscopy results showed that the β-In2S3 crystallographic phase became predominant as the substrate temperature increased. For the optical transmittance spectra, it was observed that the deposited In2S3 thin films at 300°C and with thermal annealing showed an increase in their band gap energy of nearly 60 meV. The direct energy band gap of In2S3 films varied in the range of 2.76–2.82 eV. The scanning electron microcopy image and elemental analysis shows a better morphology, and an increase in O and Sn when the In2S3 samples were subjected to thermal annealed and the substrate temperature increased, respectively. Photoluminescence spectra were obtained at room temperature and showed two emission bands around 1.75 (709 nm) and 2.35 eV (527 nm), one related to interstitial indium donor sites (Ini) and oxygen acceptor vacancies (OVs), and the second to an emission band corresponding to the transition sulfur donor-indium acceptor. As the substrate temperature increased and thermal annealing of In2S3 was performed, the 1.75 eV emission bands increased in intensity with respect to the 2.35 eV band. From the Raman measurements, it was observed that the vibrational peaks were better defined as the substrate temperature increased and In2S3 underwent thermal annealing. In addition, to study the spinel-like defect structure, the peaks corresponding to the five main vibrational modes of In2S3 were identified as the Alg mode, Eg mode, and three modes of the F2g.

Effect of "In Use" Administration on Topical Product Metamorphosis and Skin Permeation of Acyclovir Creams: Implications for Bioequivalence.

Typical clinical "in use" conditions for topical semisolids involve their application as a thin film, often with rubbing that can induce metamorphic stress. Yet, product quality and performance tests often characterize the manufactured product, and may not consider product metamorphosis (e.g., shear history) during dispensing and administration. This work sought to elucidate how such metamorphosis might alter product quality and performance. We evaluated the effect of "in use" stresses on drug crystal metamorphosis in acyclovir creams by optical microscopy. The amount of dissolved acyclovir was determined by separation of the cream base by ultra-centrifugation and quantification by HPLC. IVPT was undertaken on Zovirax® US and Aciclostad® comparing static and "in use" application of a finite dose. A mechanistic IVPT study was also conducted to understand the influence of acyclovir particle size reduction by "in use" rubbing on skin permeation. Reduction in acyclovir particle size was seen after "in use" rubbing with increases in the amount of dissolved acyclovir after rubbing (30 and 60s) compared to static for both products. "In use" application resulted in significantly higher acyclovir permeation from both products. The mechanistic IVPT study proved the role of product metamorphosis. These results highlight the role of metamorphosis of product microstructure and its influence on performance.

Nucleation, Electronic, and Optical Properties of Bi Thin Films Electrodeposited on n‐Si(111) Substrate

This study investigates the electrochemical nucleation and growth mechanisms of bismuth on a monocrystalline n‐Si(111) substrate from an acidic nitrate solution. It also examines the electrical and optical properties of the electroplated films. The qualitative analysis of the experimental current transients reveals a strong agreement with instantaneous nucleation on active sites and three‐dimensional diffusion‐controlled growth. Electrochemical kinetic parameters are derived using the Mirkin–Nilov–Heerman–Tarallo model, which is employed to fit the experimental curves. Electrochemical impedance spectroscopy and Mott–Schottky analysis are used to assess the electronic characteristics of the materials. Scanning electron microscope observations show a uniform, smooth, and continuous deposit. X‐ray diffraction analysis indicates a high texture along the [012] direction of the rhombohedral crystal structure in thin bismuth films with different thicknesses (118, 318, and 611 nm). UV–visible spectroscopy is employed to investigate the optical characteristics of the Bi/Si surface in the 200–1100 nm wavelength range. The study demonstrates that the thickness of the bismuth film affects the absorption response of the Bi/Si heterojunction, showing a notable increase in absorption in the visible and infrared ranges. Furthermore, it is found that the photoluminescence properties of the Bi/Si heterojunction are improved in the visible and infrared ranges.

Mechanisms of Secondary Spreading and Micro Droplet Formation on Steel

Abstract A new theory for secondary spreading based on the wetting theory of thin films is presented. It explains how micro droplets within the spreading zone and the primary droplet retain their shape, although connected by a thin electrolyte film and how humidity and salt concentration affect the growth rate of micro droplets. The trigger for secondary spreading, polarization or alkalization, is identified by using droplets of sodium hydroxide solution. Secondary spreading thus occurs on steel from pH 13.5 without corrosion or external polarization. The limiting pH value found explains why secondary spreading on steel only occurs when certain salts are used. 
The effect of the substrate is investigated by changing the microstructure of the steel. By comparing the sizes of micro droplets and micro structural phases and by scanning electron microscopy/energy-dispersive X-ray analysis measurements of the spreading zone, the existence of an electrolyte film connecting the micro droplets is supported. Ecorr potential profiles of secondary spreading droplets of sodium chloride solution on steel acquired by means of SKP are used to assess the contribution of secondary spreading to the total corrosion current, which is estimated to be low compared to that of the cathodic zone at the edge of the droplet

Structural and Optical Anomalies in Thin Films Grown in a Magnetic Field by Electron‐Assisted Vacuum Deposition of PTFE

AbstractPolytetrafluoroethylene (PTFE) films are deposited in parallel and perpendicular magnetic fields (MF) by electron‐enhanced vacuum deposition (EVD) and EVD + low‐temperature plasma (LTP) methods. The structure, morphology, and nanomechanical properties of the films are studied by infrared spectroscopy (IRS), atomic force microscopy (AFM), and spectroscopic ellipsometry. The structure of the thicker films is closer to that of bulk PTFE than that of thin films. The films' crystallinity and surface roughness are higher than those deposited without MF. The birefringence of the refractive index (n) of the films deposited in the MF is inverse to the anisotropy of the n of the films deposited without MF. The hardness of the films is close to that of bulk PTFE.

Toward Spatial Control of Reaction Selectivity on Photocatalysts Using Area-Selective Atomic Layer Deposition on the Model Dual Site Electrocatalyst Platform.

Photocatalytic water splitting is a promising route to low-cost, green H2. However, this approach is currently limited in its solar-to-hydrogen conversion efficiency. One major source of efficiency loss is attributed to the high rates of undesired side and back reactions, which are exacerbated by the proximity of neighboring oxidation and reduction sites. Nanoscopic oxide coatings have previously been used to selectively block undesired reactants from reaching active sites; however, a coating encapsulating the entire photocatalyst particle limits activity as it cannot facilitate both half-reactions. In this work, area selective atomic layer deposition (AS-ALD) was used to selectively deposit semipermeable TiO2 films onto model metallic cocatalysts for enhancing reaction selectivity while maintaining a high overall activity. Pt and Au were used as exemplary reduction and oxidation cocatalyst sites, respectively, where Au was deactivated toward ALD growth through self-assembled thiol monolayers while TiO2 was coated onto Pt sites. Electroanalytical measurements of monometallic thin film electrodes showed that the TiO2-encapsulated Pt effectively suppressed undesired H2 oxidation and Fe(II)/Fe(III) redox reactions while still permitting the desired hydrogen evolution reaction (HER). A planar model photocatalyst platform containing patterned interdigitated arrays of Au and Pt microelectrodes was further assessed using scanning electrochemical microscopy (SECM), demonstrating the successful use of AS-ALD to enable local reaction selectivity in a dual-reaction-site (photo)electrocatalytic system. Finally, interdigitated microelectrodes having independent potential control were used to show that selectively deposited TiO2 coatings can suppress the rate of back reactions on neighboring active sites by an order of magnitude compared with uncoated control samples.

Efficiency enhancement of WSe2/In2S3 solar cell by numerical modeling using SCAPS

Tungsten diselenide (WSe2), a transition metal dichalcogenide (TMDC) compound, is considered a promising material for application in thin film solar cells because of its high carrier transport, tunable band gap, and high absorption coefficient. In this work, solar cell structure comprising FTO/In2S3/WSe2 is modeled using one-dimensional solar cell capacitance simulator (SCAPS-1D) software where wide bandgap widely accessible In2S3 is used as a novel buffer layer instead of toxic CdS buffer layer for WSe2-based solar cell. The effect of thickness, doping concentrations, defect density, radiative recombination coefficient, and the electron and hole capture cross-section are analyzed and optimized. After optimizing the device, the effect of operating temperature, shunt and series resistance and back contact work function are also investigated. At an optimized WSe2 absorber layer thickness of 1.5 µm and acceptor density of 1017 cm−3, efficiency of 22.53%, fill factor of 84.98%, open circuit voltage of 1.096 V, and short circuit current density of 24.18 mA/cm2 was obtained. Additionally, a back surface field (BSF) layer comprising amorphous silicon (a-Si) of thickness 0.05 µm is introduced between the absorber layer and the back contact to lessen carrier recombination at the back surface. Therefore, the efficiency rises from 22.53% to 29.5% with a fill factor of 89.53%, open circuit voltage of 1.26 V, and short circuit current density of 26.23 mA/cm2. The simulation results suggest that WSe2-based thin-film solar cells can be designed and fabricated with high efficiency and cost advantage.

Disulfide-Containing Nitrosoarenes: Synthesis and Insights into Their Self-Polymerization on a Gold Surface.

Disulfide-containing nitrosoarenes with [bis(4-nitrosobenzyl) disulfide, NOBnDS (1)] or without [4-nitrosophenyl disulfide, NOPDS (2), and 1,2-bis(4'-nitroso-[1,1'-biphenyl]-4-yl)disulfane, NOBPDS (3)] an alkyl spacer between the sulfur headgroup and the aromatic moiety (phenyl in NOPDS (2) or biphenyl in NOBPDS (3)) were synthesized and used as precursors to form azodioxy thiolate films on Au(111) substrates. Due to the incorporated disulfide functionalities, these specifically designed nitrosoarenes are enabled to self-polymerize through azodioxy bonds on a gold surface. Thin films of NOBnDS (1), NOPDS (2), and NOBPDS (3) were prepared at different adsorption times via the solution-phase self-assembly of molecules onto the Au(111) surface and characterized by Raman spectroscopy, ellipsometry, water contact angle measurements, atomic force microscopy (AFM), and scanning tunneling microscopy (STM). For comparison, films of structurally analogous disulfide-containing nitro derivatives on Au(111), which can form only monolayer films, thus serving as a reference, were also fabricated and characterized. Raman spectra of NOBnDS (1), NOPDS (2), and NOBPDS (3) films on the Au(111) substrates revealed the presence of a N═N stretching band of the E-azodioxy group. Ellipsometry showed that nitrosoarenes form thicker films compared with their nitro counterparts, indicating the formation of azodioxy oligomer films. AFM revealed an island-like morphology of the nitrosoarene films, in contrast to the rather homogeneous one observed for the monolayer films of nitro derivatives. STM images of nitrosoarene films indicated the formation of poorly organized surface structures in which oligomer chains are possibly interdigitated and substantially tilted relative to the surface normal, which agrees with the relatively low values of the ellipsometry-derived thicknesses. The obtained results emphasized the influence of the substituent electronic effects on the on-surface formation of azodioxides and could be used for the future design of azodioxy thiolate films on gold surfaces.

Polymer-MOF Network Enabling Ultrathin Coating for Post-Combustion Carbon Capture.

Permeance-selectivity trade-off and high temperature resilience are key challenges in development of membranes for post-combustion carbon capture. While mixed matrix membranes (MMMs) consisting of polymers and metal organic frameworks (MOFs) offer the potential to address the challenges, they are limited by the low loading of MOFs in the thin film layer. Herein, we propose an inverse synthesis strategy to form polymer-MOF networks by copolymerizing monomers with functionalized UiO-66 nanoparticles. This process yields a finely dispersed, easily processable solution, enabling defect-free, thin polymer-MOF coatings with up to 40 wt% MOF loading within the polyethylene oxide-based polymers on polyacrylonitrile supports. The membrane with 40 wt% MOF demonstrated a 212% increment in CO2 permeance at 25 °C and maintained a selectivity of 20 at 60 °C, which is attributed to the stable diffusivity selectivity of MOFs at high temperature. Furthermore, the membrane was evaluated with mixed gas and 83% relative humidity (RH) at 60°C, achieving a CO2 permeance up to 2793 GPU and a CO2/N2 selectivity of 21.6. This work offers insights into the design of practical mixed matrix membranes, which not only paves the way towards energy efficient carbon capture from flue gas, but also provides more possibilities for other applications.

Abnormal widening of the domain touching the electrode during in-plane local switching in lithium niobate

The qualitatively different domain evolution scenarios for different polarities of applied voltage pulses have been studied. For positive pulse, the domain demonstrates only slight width increase during further switching and high stability during subsequent domain imaging. For negative pulse, faster domain widening at the electrode as compared to the domain base leads to change in the type of charged domain wall (CDW) from tail-to-tail (t2t) to head-to-head (h2h) as well as formation of the domain teeth at CDW and an array of wedge-like domains. Additional domain imaging leads to reconstruction of the wedge-like domain with t2t CDW. It was demonstrated by numerical simulation that the switching field is above the threshold for step generation in wide region along the electrode. This field stimulates the formation of above-mentioned domain structure. The absence of this effect for positive pulse has been attributed to the huge difference in conductivity of t2t and h2h CDWs. The current along conductive h2h CDW after domain touching results in decrease in the tip bias due to voltage drop on the series resistance. The stability of the domains growing from the tip was attributed to effective screening of depolarization field by the injected charge. The ineffective screening at the electrode due to absence of charge injection stimulates domain backswitching. The obtained knowledge is useful for further development of domain engineering methods in thin films for the fabrication of periodically poled waveguides.

Effect of Annealing Temperatures on Structural and Electrochemical Properties of Li[Ni0.5Co0.25Mn0.25]O2 Film Cathodes

Abstract Thin films of Li[Ni0.5Co0.25Mn0.25]O2 were prepared by RF-sputtering technique post-annealed the deposited films at various temperatures in a controlled oxygen atmosphere. The annealing temperature played an important role in the crystallinity of the films. The films post-annealed at optimized temperature displayed an X-ray diffraction peak at 18.29o, which can be ascribed to the Braggs reflection (003) of hexagonal Li[Ni0.5Co0.25Mn0.25]O2. The lattice parameters of the optimized films were a=2.85Å and c=14.45Å with c/a ratio equal to 5.070. The electrochemical activity of the post-annealed films was methodically investigated. The discharge capacity offered by the films is 40μAh/cm2μm at 300°C however this was further improved to 57.5 μAh/cm2.μm by post-annealing at 700°C. Due to structural integrity of Li[Ni0.5Co0.25Mn0.25]O2 film may be used as cathode material for energy storage devices.

Polymer‐MOF Network Enabling Ultrathin Coating for Post‐Combustion Carbon Capture

Permeance‐selectivity trade‐off and high temperature resilience are key challenges in development of membranes for post‐combustion carbon capture. While mixed matrix membranes (MMMs) consisting of polymers and metal organic frameworks (MOFs) offer the potential to address the challenges, they are limited by the low loading of MOFs in the thin film layer. Herein, we propose an inverse synthesis strategy to form polymer‐MOF networks by copolymerizing monomers with functionalized UiO‐66 nanoparticles. This process yields a finely dispersed, easily processable solution, enabling defect‐free, thin polymer‐MOF coatings with up to 40 wt% MOF loading within the polyethylene oxide‐based polymers on polyacrylonitrile supports. The membrane with 40 wt% MOF demonstrated a 212% increment in CO2 permeance at 25 °C and maintained a selectivity of 20 at 60 °C, which is attributed to the stable diffusivity selectivity of MOFs at high temperature. Furthermore, the membrane was evaluated with mixed gas and 83% relative humidity (RH) at 60°C, achieving a CO2 permeance up to 2793 GPU and a CO2/N2 selectivity of 21.6. This work offers insights into the design of practical mixed matrix membranes, which not only paves the way towards energy efficient carbon capture from flue gas, but also provides more possibilities for other applications.

A Material Design Guideline for Self-assembled Vertically Aligned Nanocomposite Thin Films

Abstract Nanocomposite thin films, comprising two or more distinct materials at nanoscale, have attracted significant research interest considering their potential of integrating multiple functionalities for advanced applications in electronics, energy storage, photonics, photovoltaics, and sensing. Among various fabrication technologies, a one-step pulsed laser deposition (PLD) process enables the self-assembly of materials into vertically aligned nanocomposites (VANs). The demonstrated VAN systems include oxide-oxide, oxide-metal, and nitride-metal VAN films and their growth mechanisms are vastly different. These complexities pose challenges in the designs, materials selection, and prediction of the resulted VAN morphologies and properties. The review examines the key roles that surface energy plays in the VAN growth and provides a generalized materials design guideline combining the two key factors of surface energy and lattice strain / mismatch, along with other factors related to growth kinetics that collectively influence the morphology of VAN films. This review aims to offer valuable guidelines for future material selection and microstructure design in the development of self-assembled VAN films.