Inorganic Films Research Articles

Dendrite-Free and Highly Stable Zn Metal Anode with BaTiO3/P(VDF-TrFE) Coating

Aqueous rechargeable Zn metal batteries have garnered increasing attention due to their high theoretical capacity, high safety, and low cost. However, their commercialization has been impeded by the rapid cycling deterioration caused by side reactions and dendrite growth on Zn anodes. The present work explores a dielectric organic–inorganic film with a hydrophobic surface to circumvent these problems and suppress dendrite growth on the zinc anode. Dielectric BaTiO3/P(VDF-TrFE) (BTO/PVT) coating has been demonstrated to promote uniform zinc deposition and inhibit dendrite growth. The hydrophobic surface also regulates the Zn-ion desolvation process at the interfaces and is crucial in preventing water from harming the Zn anode surface, leading to a dendrite-free surface and little formation of byproducts. The resulting BTO/PVT@Zn anode has a long lifespan of 3000 h and an average Coulombic efficiency of 99.6% at 1 mA cm–2. In addition, the BTO/PVT@Zn||NH4V4O10 full cell shows a good rate capability and a long cycling lifespan.

P‐30: Analysis of Deterioration Mechanism of Sealing Force in LTPS‐LCD 7 mask Technology and Improve Mode

With an inbuilt structure of using the inorganic film passivation layer instead of the organic layers in Liquid Crystal Display with 7mask technology, sealing force is deteriorated. This paper is devoted to find the mechanism of the deterioration and developed a way to improve.

Inorganic Perovskite Surface Reconfiguration for Stable Inverted Solar Cells with 20.38% Efficiency and Its Application in Tandem Devices.

Inorganic perovskite solar cells (IPSCs) have garnered attention in tandem solar cells (TSCs) due to their suitable bandgap and impressive thermal stability. However, the efficiency of inverted IPSCs has been limited by the high trap density on the top surface of inorganic perovskite film. Herein, a method for fabricating efficient IPSCs by reconfiguring the surface properties of CsPbI2.85 Br0.15 film with 2-amino-5-bromobenzamide (ABA) is developed. This modification not only exhibits the synergistic coordination of carbonyl (C=O) and amino (NH2 ) groups with uncoordinated Pb2+ , but also the Br fills halide vacancies and suppresses the formation of Pb0 , effectively passivating the defective top surface. As a result, a champion efficiency of 20.38%, the highest efficiency reported for inverted IPSCs to date is achieved. Furthermore, the successful fabrication of a p-i-n type monolithic inorganic perovskite/silicon TSCs with an efficiency of 25.31% for the first time is demonstrated. Crucially, the unencapsulated ABA-treated IPSCs shows enhanced photostability, retaining 80.33% of its initial efficiency after 270h, and thermal stability (maintain 85.98% of its initial efficiency after 300h at 65°C). The unencapsulated ABA-treated TSCs also retains 92.59% of its initial efficiency after 200h under continuous illumination in ambient air.

A simple solution method to prepare VO2:Co2+ precursors for thin film deposition by solution-processing method

Solution-processing is a low-cost solution method to preparea variety of organic or inorganic thin films. For metal oxide compounds, a solution-processing solution of an organometallic compound is frequently used as a precursor to be spin coated, followed by a thermal annealing to form metal oxide. In this work, vanadium oxide powders are obtained from a simple acid-base reaction, and then they are dispersed in isopropyl alcohol to form a solution for spin-coating. Different amount of cobalt salt are also added together with VOx into isopropyl alcohol to form VOx:Co2+ solutions. After thermal annealing at 200 °C, continuous transparent thin films are obtained. Optical, structural, morphological and chemical binding energies of those films are analyzed. It is found that amorphous VO2:Co2+ compound is formed in those films with V:Co atomic ratios between 6.6:1 and 1.6:1. Optical absorption onsets of those films are around 2.3 eV. An interesting interconnected porous morphology is observed when the atomic ratio of V:Co is around 4.9:1. It is concluded that porous amorphous cobalt doped vanadium oxide thin films can be obtained from a spin-coating process at low annealing temperature from a simple solution without any complex agent.

Toroidal dipoles in tunable THz metamaterial based on perovskite

In recent years, there has been an increasing variety of researches and related applications on terahertz (THz). It is a new type of radiation source whose radiation lies in the so-called terahertz gap. However, due to the limitations of natural materials, the terahertz band rarely has effective response. Metamaterials, which have emerged in recent years, are artificial composite electromagnetic materials composed of periodic elements. In the terahertz band, it has special physical properties not found in natural materials. Toroidal dipoles can be detected by modeling tunable terahertz metamaterials. A tunable toroidal dipole device based on a perovskite terahertz metamaterial combining perovskite with organic and inorganic hybrid halide perovskite films is proposed. The optical parameters of perovskite can be changed from toroidal dipole to magnetic dipole and electric dipole by pumping light. This research is of great significance to the design of terahertz devices such as filters and modulators.

Investigating the Trade‐off between Optical and Mechanical Properties during Constrained Sintering of Mesomorphic Ceramic Films

AbstractRobust, transparent, and birefringent inorganic films are demanded for polarization control of high‐power lasers. While single crystals or films obtained via glancing angle deposition exhibit desirable optical properties and laser damage resistance, these methods are limited by cost and scalability. Mesomorphic ceramics as inorganic solids with liquid crystalline superstructure offer appealing transparency and birefringence but lack mechanical robustness due to their high porosity. Here, the effect of sintering on optical and mechanical properties of mesomorphic ceramics is evaluated. Films prepared by blade coating are sintered under varying conditions. Constrained sintering accomplished crystallite growth, densification, and morphological changes including necking as well as cracking while preserving the crystallographic orientation. The extent of sintering as a function of thermal treatment is quantified by morphology, surface area loss, and crystallite growth. Moreover, activation energies for surface diffusion and grain growth are estimated by surface area analysis and X‐ray diffraction peak narrowing, respectively. After sintering, birefringence decreases while Young's modulus and hardness improve as the film densifies. Upon partial sintering, mesomorphic ceramics retain transparency, high birefringence, and enhanced modulus. Laser‐induced damage threshold is measured as well. The reported results represent an important step toward the assembly and sintering of robust waveplates with high laser damage resistance.

Molecular Layer Deposition of Organic–Inorganic Hafnium Oxynitride Hybrid Films for Electrochemical Applications

The molecular layer deposition (MLD) method can be used to deposit hybrid organic–inorganic films with precisely defined composition, flexible properties, and conformality on different substrates. In this study, hafnium-based organic–inorganic hybrid polymer films were studied as potential coatings for silicon nanoparticles (SiNPs) used in composite lithium-ion battery (LIB) anodes, an application which requires the film to be both flexible and stable under electrochemical conditions. Hf-hybrid films were successfully deposited by MLD using sequential exposure of the homoleptic tetrakis(dimethylamido) hafnium complex and ethanolamine as the reactants. The self-limiting surface reactions lead to a constant growth per cycle (GPC) of ∼2.0 Å/cycle at 120 °C. Temperature-dependent growth was observed, with the GPC decreasing from ∼2.5 to ∼1.1 Å/per cycle as the temperature was increased from 65 to 145 °C. Scanning transmission electron microscopy and electron energy loss spectroscopy mapping confirm that a thin, dense, and conformal Hf-based MLD layer is deposited on the SiNPs. The presence of expected C–N, C–O, and −CH2 moieties in the MLD films was confirmed by Fourier transform infrared spectroscopy. Hafnium nitride and hafnium oxide bonds within the hybrid thin films were identified by X-ray photoelectron spectroscopy. Characterization results indicated that the deposited hafnium-based organic–inorganic hybrid films contain both metal oxynitride bonds and organic bonds, including C–C, C–O, and C–N. This Hf-based MLD thin film was tested on LIB SiNP composite anodes as an artificial solid–electrolyte interphase, with results showing that the capacity retention increased by about 35% after 110 cycles in a LIB application.

CsPbI3 perovskite solar cell and decoding its skink feature in J-V curve

Skink feature in the current density-voltage (J–V) characteristic is observed in an inorganic perovskite CsPbI3 thin film solar cell. The fabricated CsPbI3 solar cell attained maximum efficiency of 8.8% under one sun illumination. It showed a prominent skink phenomenon in the positive biasing region near the open-circuit voltage in the illuminated J–V curve. Skink is a curvilinear s-shape feature in J-V that dramatically deteriorate the fill factor. This study explored the probable cause of such a skink feature by theoretical modelling. It is observed that energy level mismatch, through a relatively high valence band offset (VBO) barrier at the hole transport layer HTL/perovskite junction along with a bulk defect in perovskite, replicates the skink feature in simulated J-V. We showed a one-to-one relation between the skink feature in the J-V curve and its steering parameters in the CsPbI3 device. This one-to-one dependence provides a peek into the device's working and is of great help for understanding the defect physics of experimental devices.

Environmental lead-free Cs3Bi2I9 films deposited by vapor transport deposition for stable all-inorganic solar cells

The non-lead metal halides are of wide interest due to their low toxicity and good stability compared with lead-based perovskites. Among them, Cs3Bi2I9 is of interest because of its excellent electronic and optical properties. In this study, high-quality Cs3Bi2I9 films with large grains and good uniformity were deposited for the first time by a vapor transport deposition (VTD) approach using a mixture of CsI and BiI3 crystal powders as evaporation sources. The Cs3Bi2I9 film was then used as an absorber layer in the solar cell using a superstrate structure with FTO/TiO2/Cs3Bi2I9/CuI/Au. Due to the different melting points of CsI (626 °C) and BiI3 (408 °C), the CsI to BiI3 molar ratio can significantly affect the stoichiometry, structure, and optoelectronic properties of the prepared Cs3Bi2I9 films, which ultimately determine the performance of the Cs3Bi2I9 solar cells. The all-inorganic Cs3Bi2I9 solar cell can achieve a maximum PCE of 1.52% and remain at 80% of its initial value after one month of storage in the air without encapsulation. This work provides a new route to deposit inorganic perovskite films using evaporation sources with different melting points, which has promising applications in solar cells and photodetectors.

Understanding the Effects of Primary and Secondary Doping via Post‐Treatment of P‐Type and N‐Type Hybrid Organic–Inorganic Thin Film Thermoelectric Materials

AbstractHybrid organic/inorganic materials have emerged as promising thermoelectric (TE) materials since they inherit the individual strengths of each component, enabling rational materials design with enhanced TE performance. The doping of hybrid TE materials via post‐treatment processes is used to improve their performance, but there is still an incomplete understanding of the elicited effects. Here, the impact of different doping methods on the thin film TE performance of p‐type Te/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and n‐type Ag2Te/PEDOT:PSS hybrid materials is investigated. Primary doping through acid–base and charge transfer processes using H2SO4 and tetrakis(dimethylamino)ethylene, respectively, and the effects of secondary doping using ethylene glycol is examined. Through a combination of Hall effect measurements, hard X‐ray photoelectron spectroscopy, and Raman spectroscopy, variations in the charge carrier concentration, mobility, and overall TE performance are related to the morphological and chemical structure of the hybrid materials. This study provides an improved understanding of the effects that different post‐treatments have on hybrid materials and shows that the impact of these post‐treatments on pure PEDOT:PSS does not always apply to hybrid systems. These new insights into post‐treatment effects on hybrid materials is expected to facilitate further enhancement of their performance as electronic materials in general and thermoelectric materials in particular.

Two‐Step Vapor‐Solid Reaction for the Growth of High‐Quality CsFA‐Based Lead Halide Perovskite Thin Films

Thin‐film solar cells based on organic–inorganic hybrid perovskite light absorbers have attracted intense attention both from the scientific and industrial communities in recent years. Researchers worldwide have developed various strategies for depositing high‐quality perovskite thin films including composition optimization, surface modification, and solvent engineering. However, these strategies are mainly based on the perovskite thin films which are deposited via solution processes. Though vacuum and vapor‐based techniques have been widely used in the modern thin‐film industry, these technologies still need further developments for the deposition of high‐quality organic–inorganic hybrid perovskite thin films. Herein, a novel two‐step vapor–solid reaction procedure for the deposition of high‐quality methylamine‐free hybrid perovskite thin films is proposed. The first vapor–solid reaction step gives the perovskite a proper chemical stoichiometric ratio, and the second step can refine the crystallinity of the film. Therefore, by utilizing this method, it is possible to obtain high‐quality perovskite thin films with larger grain sizes and lower tap densities. Consequently, perovskite solar cells based on these films have achieved a high power conversion efficiency of 20.79%.

Interfacial engineering by applying double CdS structure electron transport layer for high-performance Sb2(S,Se)3 solar cells

Antimony sulfoselenide (Sb2(S,Se)3) has been demonstrated as a promising photoabsorber for stable inorganic thin film photovoltaics with high performance. Optimizing interfacial contact and reduce the defects are essential in restraining the recombination of photo-induced carrier at heterojunction interface. In particular, the electron transport layer (ETL) directly affects the quality of Sb2(S,Se)3 absorber layer as well as the performance of the device. Herein, an available and highly effective double CdS ETL is proposed to modify the heterojunction interface contact which moreover enhance the efficiency of Sb2(S,Se)3 solar cells. The optimal matching of the two CdS ETLs were fully investigated, and by following this process, the ETL with high crystallinity and density is obtained, rendering high-quality Sb2(S,Se)3 thin films as well. Besides, the final devices exhibit lower series resistance and larger Jsc, FF, enabling improvement of the efficiency from 3.09% to 6.94%. This study provides an effective method for the surface engineering of CdS ETLs to achieve high-performance Sb2(S,Se)3 solar cells.

Microstructure control and property switching in stress-free van der Waals epitaxial VO2 films on mica

Realizing stress-free inorganic epitaxial films on weakly bonding substrates is of importance for applications that require film transfer onto surfaces that do not seed epitaxy. Film-substrate bonding is usually weakened by harnessing natural van der Waals layers (e.g., graphene) on substrate surfaces, but this is difficult to achieve in non-layered materials. Here, we demonstrate van der Waals epitaxy of stress-free films of a non-layered material VO2 on mica. The films exhibit out-of-plane 010 texture with three in-plane orientations inherited from the crystallographic domains of the substrate. The lattice parameters are invariant with film thickness, indicating weak film-substrate bonding and complete interfacial stress relaxation. The out-of-plane domain size scales monotonically with film thickness, but the in-plane domain size exhibits a minimum, indicating that the nucleation of large in-plane domains supports subsequent island growth. Complementary ab initio investigations suggest that VO2 nucleation and van der Waals epitaxy involves subtle polarization effects around, and the active participation of, surface potassium atoms on the mica surface. The VO2 films show a narrow domain-size-sensitive electrical-conductivity-temperature hysteresis. These results offer promise for tuning the properties of stress-free van der Waals epitaxial films of non-layered materials such as VO2 through microstructure control.

Comparative study of liquid crystal variable retarder with rubbed polyimide and SiO2 thin films by glancing angle deposition

A comparative study on the optical, morphological and laser-induced damage characteristics of rubbed polyimide, SiO2 thin films by glancing angle deposition, and the corresponding liquid crystal (LC) retarders, is presented in this paper. SiO2 inorganic thin films were prepared with a deposition angle of 45[Formula: see text], and traditional polyimide (PI) films were prepared by spin coating and rubbing. The experimental results indicate that the SiO2 thin films have a good transmittance and resistance to laser damage. The transmittance of the SiO2 thin films was above 92% in the wavelength range 400–1200 nm, and that of the corresponding LC retarder was approximately 90% in the wavelength range 800–1200 nm. The laser-induced damage threshold of the SiO2 thin films reached 32.6 J/cm2, and that of the corresponding LC retarder was 1.84 J/cm2. These results are better than those of the PI alignment films. SiO2 thin films have potential for use in the LC optical devices for laser applications.

Epitaxial inorganic metal-halide perovskite films with controlled surface terminations

Metal-halide perovskite (MHP) thin films for next-generation solar cells are typically fabricated by wet-chemical synthesis in which surface properties such as the orientation of surface facets and their termination cannot be controlled. MHP device efficiencies depend critically on those surface properties. We demonstrate the epitaxial growth of several nanometer thick purely (001)-orientated films of ${\mathrm{CsPbBr}}_{3}$ and ${\mathrm{CsSnBr}}_{3}$ MHPs on Au(001) by molecular beam epitaxy. The epitaxial films are in a cubic phase aligned with the substrate. Their surfaces are singly terminated and can be modified for the first time. While the CsBr and ${\mathrm{PbBr}}_{2}$ surface terminations differ in terms of their atomic structure and defect content, the films are intrinsic semiconductors irrespective of the termination. The work function of the ${\mathrm{PbBr}}_{2}$-terminated surface is increased by $0.7\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$, which has drastic implications for the level alignment at MHP interfaces.

Surface in situ reconstruction of inorganic perovskite films enabling long carrier lifetimes and solar cells with 21% efficiency

Surface in situ reconstruction of inorganic perovskite films enabling long carrier lifetimes and solar cells with 21% efficiency

Defect tolerant Cs2SnI6 double perovskite thin films with ultrahigh carrier lifetime for high efficiency solar cells

Phase pure, device quality inorganic Cs2SnI6 double perovskite thin films are grown using thermal evaporation method. Both sequential and co-evaporation methods are attempted and preliminary analysis confirmed that the samples prepared by co-evaporation technique are more stable, demonstrating better properties. Effect of variation in the CsI/SnI2 ratio on the properties of Cs2SnI6 samples prepared using co-evaporation method are studied. CsI impurity phase is found to be suppressed when the ratio is reduced to 1:1. The films possess a direct bandgap of ∼1.53 eV and a polygon morphology with grains of size ∼0.4 μm. Depth-wise elemental analysis using XPS substantiated the uniform distribution of all the elements throughout the material without any additional phases. The sample has exceptionally high minority carrier lifetime of the order of 9.6 μs as determined from the time-resolved photoluminescence. The work function and valence band maximum of Cs2SnI6 film are found to be located at 4.9 eV and 6.31 eV respectively. These findings highlight the superior properties of the co-evaporated Cs2SnI6 thin film for the application as an absorber layer in solar cells.

Corrosion Inhibition Mechanism of Ultra-High-Temperature Acidizing Corrosion Inhibitor for 2205 Duplex Stainless Steel

The acidizing corrosion inhibitors reported so far have a poor effect on duplex stainless steel in high-temperature and high-concentration acid systems and cannot effectively inhibit the occurrence of selective corrosion. In this paper, a new acidizing corrosion inhibitor was designed, which was mainly composed of Mannich base and antimony salt. The inorganic substance in the corrosion inhibitor had good stability at high temperatures and could quickly form a complex with the metal matrix to enhance the binding ability. The organic substance can make up for the non-dense part of the inorganic film. The properties of developed corrosion inhibitors were analyzed by quantum chemical calculation, molecular dynamics simulation, and scanning electron microscopy. The results showed that a double-layer membrane structure could be constructed after adding the corrosion inhibitor, which could play a good role in blocking the diffusion of acid solution at high-temperature. The uniform corrosion rate of 2205 duplex stainless steel after adding acidizing corrosion inhibitor immersion in a simulated service condition (9 wt.% HCl + 1.5 wt.% HF + 3 wt.% CH3COOH + 4~6 wt.%) at 140 °C, 160 °C and 180 °C for a 4 h test is 6.9350 g·m-2·h-1, 6.3899 g·m-2·h-1 and 12.1881 g·m-2·h-1, respectively, which shows excellent corrosion inhibition effect and is far lower than that of the commonly accepted 81 g·m-2·h-1 and no selective corrosion could be detected.

Membrane Fabrication and Modification by Atomic Layer Deposition: Processes and Applications in Water Treatment and Gas Separation.

Membrane-based separation processes are part of most water purification plants worldwide. Industrial separation applications, primarily water purification and gas separation, can be improved with novel membranes or modification to existing ones. Atomic layer deposition (ALD) is an emerging technique that is proposed to upgrade certain kinds of membranes independent of their chemistry and morphology. ALD deposits thin, defect-free, angstrom-scale, and uniform coating layers on a substrate's surface by reacting with gaseous precursors. The surface-modifying effects of ALD are described in the present review, followed by a description of various types of inorganic and organic barrier films and how these can be used in combination with ALD. The role of ALD in membrane fabrication and modification is categorized into different membrane-based groups according to the treated medium, i.e., water or gas. In all membrane types, the ALD-based direct deposition of inorganic materials, mainly metal oxides, on the membrane surface can improve antifouling, selectivity, permeability, and hydrophilicity. Therefore, the ALD technique can broaden the applications of membranes to the treatment of emerging contaminants in water and air. Finally, the advancement, limitations, and challenges of ALD-based membrane fabrication and modification are compared to provide a comprehensive guideline for developing next-generation membranes with improved filtration and separation performance.

High quality quasi-two-dimensional organic–inorganic hybrid halide perovskite film for high performance photodetector

Two-dimensional (2D) Ruddlesden–Popper perovskites have attracted extensive attention in photodetectors (PDs) due to their exceptional optoelectronic properties. The performances of PDs show extremely strong dependence on defects in 2D perovskites. Herein, high quality and less defective BA2FAPb2I7 perovskite films were obtained by a simple one-step spin coating method with rare earth doping assisted crystal growth. Furthermore, BA2FAPb2I7 perovskite films were used as photoresponsive materials to fabricate architectural simplicity photoconductor PDs. Under 405 nm laser illumination, the PDs show remarkable balance detect properties with a low dark current of 5.1 × 10−11 A, a large on/off ratio of 2.2 × 105, a high responsivity (R) of 4.51 A/W, an outstanding detectivity Dshot* of 4.31 × 1013 Jones, and a response speed of 80 μs/76 μs. The R and Dshot* of the PDs are outstanding in the reported quasi-2D perovskite PDs with the same structure. Our work not only paves an indubitably feasible way for fabrication of quasi-2D perovskite PDs via improving their natural material properties but also provides a clear direction for further enhancing the performance of other perovskites optoelectronics.