Organic Inorganic Hybrid Films Research Articles

Optical properties of an organic-inorganic hybrid film made of regenerated cellulose doped with light-scattering TiO2 particles

Inorganic-organic composites offer immense potential for developing materials with, e.g. improved chemical, optical and electrical properties, by combining characteristics from both substances. In this study, sustainable and modifiable regenerated cellulose films were produced via an ionic liquid process and combined with the excellent properties of titanium dioxide (TiO2) particles to prepare highly light-scattering and UV-absorbing composite film materials. Films with varying TiO2 loadings were cast onto plastic supports and regenerated in water. The resultant TiO2-regenerated cellulose films exhibited homogenous particle dispersion throughout the materials, while some particle size differentiation was observed with scanning electron microscopy, confocal microscopy, energy dispersive X-ray spectroscopy and elemental mapping. Remarkably, the Elrepho spectrophotometer and UV–Vis transmittance and absorbance results confirmed excellent scattering properties for the high-doped TiO2 films in the visible light wavelengths (80%→10% reduction in light transmittance), while complete UV light blocking was achieved even with very low (>0.5–1%) TiO2 addition levels. Furthermore, the TiO2-doped cellulose films also exhibited capabilities for UV activation. TiO2 loading also increased forward and backward scattering of the films, and the laser beam heating rate of the films was affected by both the doping level and thickness of the films. The developed composite material exhibited excellent light-scattering properties with UV shielding capabilities, confirming the potential of the composite for such advanced purposes as photoelectronic, agricultural or packaging applications.

Highly reliable double-layer coatings on magnesium alloy surfaces for robust superhydrophobicity, chemical durability and electrical property

The long application life and reliable performance of magnesium alloys have been putting forward strict requirements for both better chemical stability and functional characteristics of protective coating. Herein, a highly reliable superhydrophobic double-layer coating on AZ31 Mg with excellent anti-corrosion and electrical protection was achieved by assembling modified SiO2-based organic-inorganic hybrid films on Plasma Electrolytic Oxidation (PEO) ceramic bottom layer. The coating exhibits preferable antiwater surfaces with a barrier layer isolating the underlying substrate from the external environment, rendering a long-term active corrosion protection for the multilayer covered magnesium alloy. Remarkably, the coating achieves high electric insulation with volume resistivity of 1.7 × 1012 Ω cm, breakdown voltage of 1405.2 ± 117.1 V and dielectric strength of 40.2 ± 3.3 V/μm. Simultaneously, its dielectric properties with a low dielectric constant (ε ≈ 3.75) and a low dielectric loss (tan δ ≈ 0.0058) outperform those of some current dielectric coatings with similar components. Moreover, the superhydrophobic coating displays strong mechanical robustness undergoing 50th linear abrasion, superior environmental stability (thermal shock, prolonged solution immersion, salt-spray corrosion and UV irradiation), and high adhesion strength. The excellent multifunction benefits from the introduction of ceramic bottom layer, the assembly of compact nanocomposite films, and the synergistic effect of organic-inorganic components. This study provides a new inspiration for designing advanced protective coating with a great potential for the applications of sensitive electronic devices.

One-step fabrication of high refractive index inorganic nanostructures

Direct printing of spin-on functional films is probably the most efficient method to develop low-cost novel photonic nanodevices, such as diffraction gratings, planar waveguides, nano- lasers, and antireflective coatings. For these applications high refractive index transparent materials are demanded; however, this class of materials generally requires inorganic oxides, well known for their hardness, typical of ceramic materials, and so incompatible with a soft character of printable resins. Herein, inorganic high refractive index TiO2 micro- and nano- structures, with unusual depth up to 600 nm and aspect ratio larger than 5, are obtained by combining thermal nanoimprint lithography (NIL) with UV curing. To achieve printed patterns, a hybrid organic-inorganic spin-on film is deposited at low-temperature by sol–gel processing. Two distinct bottom-up synthetic approaches are used, called in situ and ex situ, using titanium isopropoxide (90%) or TiO2 anatase nanoparticles (70%), respectively, and adding a silica sol modified by organic moieties. The two syntheses were optimized to obtain, after patterning by thermal imprint, amorphous or crystalline titania crack-free micro- and nano- patterns for in situ and ex situ, respectively. The further UV irradiation converts imprinted films to totally inorganic patterns, through the titania photocatalytic effect, allowing refractive indexes up to 1.82 at 632 nm to be achieved. This novel strategy of combining thermal imprint with UV exposure allows inorganic deep patterns to be fabricated without a calcination step, which is generally needed for inorganic resists processing. Eventually, a thermal treatment only at 300 °C can be applied to achieve a final refractive index of 2 at 632 nm.Direct printing of spin-on TiO2 high refractive index (1.82 @632 nm) transparent films, with depth up to 600 nm, aspect ratio larger than 5 and without lateral shrinkage are obtained combining thermal Nanoimprint Lithography (NIL) with UV curing.

Investigation of Aging Effects in Thermoelectric Surface Anchored Metal-Organic-Framework (SURMOFs) Films Using Nanoindentation

Thin films of Metal-organic-framework (MOF) materials are deposited using a layer-by-layer (LBL) liquid phase epitaxy (LPE) technique. The highly oriented Surface Anchored Metal-Organic Framework (SURMOFs) of Cu3(BTC)2 (BTC: benzenetricarboxylicacid), known as HKUST-1 MOF were grown on Si (100) substrates. MOF materials are designed scaffold-like compounds that consist of metal ions connected by organic ligands, forming highly ordered porous structures. MOF materials found their way to various applications including gas storage due to high storage capacity and device applications in thermoelectrics and microelectronics [1,2]. The thermoelectric application potential of HKUST-1 SURMOF films is based on their large Seebeck coefficient and the premise that the electrical properties of the otherwise insulating MOF films can be custom tailored by loading the porous MOF structure with metal clusters. For modulating the electrical conductivity of MOF films the most effective method is to infiltrate guest molecules inside the porous framework to transport ions, and hence to modulate the electrical properties of the host framework. With nanoindentation testing of the fresh and aged pristine and TCNQ loaded samples, we demonstrate that aging effects impacted the mechanical properties of the films. The aged pristine samples hardness is 0.29 GPA as compared to the fresh as-grown pristine sample of 0.16 GPA at depth of indentation/film thickness (Similarly for the TCNQ loaded samples the hardness of the aged and fresh samples is 0.22 and 0.05 GPA respectively. As hybrid organic-inorganic thermoelectric materials HKUST-1 SURMOF films are subject to aging effects. References Mazure and A.J. Auberton-Herve, Proc. of 35th European Solid-State Device Research Conf. ESSDERC, p. 29 (2005)A. Langdo, M. T. Currie, Z.-Y. Cheng, J.G. Fiorenza, M. Erdtmann, G. Braithwaite, C.W. Leitz, C.J. Vineis, J. A. Carlin, A. Lochtefeld, M. T. Bulsara, I. Lauer, D.A. Antoniadis, M. Somerville, Solid-State Electronics, 48 , 1357 (2004). Figure 1

Vapor-Phase Molecular Doping in Covalent Organosiloxane Network Thin Films Via a Lewis Acid-Base Interaction for Enhanced Mechanical Properties.

Incorporating inorganic components in organosiloxane polymer thin films for enhanced mechanical properties could enable better durability and longevity of functional coatings for a multitude of applications. However, molecularly dispersing the inorganic dopants while preserving the cyclosiloxane rings represents a challenge for cross-linked organosiloxane networks. Here, we report a molecular doping strategy using vapor-phase infiltration. On the basis of the proper Lewis acid-base interaction between diethyl zinc (DEZ) and cyclotrisiloxane rings, we achieved a complete infiltration of the organometallic precursors and well-distributed Zn-OH terminal groups formed in the initiated chemical vapor deposited poly(1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane) (PV3D3) films. X-ray photoelectron spectroscopy and nanoscale infrared spectroscopy together with density functional theory simulation reveal that the formation of a Lewis acid-base adduct rather than a ring-opening process is possibly involved in anchoring DEZ in the cross-linked network of PV3D3. Because of the incorporation of Zn-OH components, the organic-inorganic hybrid films obtained via our vapor-phase molecular doping exhibit a 10.2% larger elastic modulus and 67.0% higher hardness than the pristine PV3D3. Unveiling the reaction mechanisms between organometallic precursors and cross-linked organic networks provides new insights for expanding the vapor-phase processing strategies for engineering hybrid materials at the nanoscale.

Performance enhancement of p-type organic thin-film transistors by surface modification of hybrid dielectrics

The quality of the dielectric/organic semiconductor interface is a critical issue, because it determines the charge transport properties in organic thin-film transistors (OTFTs). High- k organic-inorganic hybrid films have received considerable attention for their outstanding dielectric properties, including low leakage currents, high breakdown fields, and suitable band offsets against the organic semiconductor. However, Hf and Zr hybrid gate dielectrics on p-type OTFTs show poor charge transport properties in the organic semiconductor channel, due to the polaron disorder elicited by the high- k properties and the presence of the –N(CH 3 ) 2 polarity (hole trapper) on the dielectric/semiconductor interface. In this report, the surface of the Hf and Zr hybrid dielectrics was capped by an ultra-thin poly-1,3,5-trivinyl-1,3,5,-trimethyl-cyclosiloxane (pV3D3) layer formed via an initiated chemical vapor deposition (iCVD) process, to modify the hybrid dielectrics/semiconductor interface. The pV3D3-capped Hf and Zr hybrid OTFTs show an enhanced V T stability while a large amount of V T shift was observed from the Hf and Zr hybrid OTFTs. This large amount of V T shift is attributed to the hole trap sites originated by –N(CH 3 ) 2 on the uncapped hybrid dielectrics. Furthermore, the p-type OTFTs with the pV3D3-capped hybrid dielectrics show a higher mobility than those with the uncapped hybrid dielectrics. The presence of the non-polar/low- k pV3D3 on the hybrids contribute to narrow the density of state (DOS) in the organic channel, improving the charge transport properties. This combined approach using the bulk layer of Hf and Zr hybrid films and the pV3D3 capping layer can overcome the limitations of single-layer hybrid dielectrics and improve the overall device performance of the OTFTs. • Performance Enhancement of p-type OTFTs through simple surface modification. • Ultra-thin (~1 nm) non-polar low-k dielectric on the hybrid. • Simple process to change the surface properties. • Systematic investigation of interface quality which affect charge transport in organic semiconductor.

Wafer-scale quasi-layered tungstate-doped polypyrrole film with high volumetric capacitance

Layered materials are particularly attractive for supercapacitors because of their unique physical, electrical and chemical properties. Here, we demonstrate a facile and scalable electrochemical deposition method for wafer-scale synthesis of quasi-layered tungstate-doped polypyrrole films (named TALPy) with controllable thickness and size. The as-prepared TALPy film exhibits a high gravimetric density and excellent volumetric capacitance, exceeding many high-performing carbon- and polymer-based film electrodes. Based on combined results of ex-situ X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS), it is determined that TALPy stores charge through an ion intercalation process accompanied by change in oxidation states of polypyrrole backbone, which is referred as intercalation pseudocapacitance. All these results suggest the great promise of electrochemical deposition as a scalable and controllable bottom-up approach for synthesizing quasi-layered conductive organic-inorganic hybrid films for electrochemical energy storage applications with high volumetric performance.

Hexameric to Trimeric Lanthanide-Included Selenotungstates and Their 2D Honeycomb Organic-Inorganic Hybrid Films Used for Detecting Ochratoxin A.

Two types of organic-inorganic hybrid structure-related lanthanide (Ln)-included selenotungstates (Ln-SeTs) [H2N(CH3)2]11Na7[Ce4(H2PTCA)2(H2O)12(HICA)]2[SeW4O17]2[W2O5]4[SeW9O33]4·64H2O (1, H3PTCA = 1,2,3-propanetricarboxylic acid, H2ICA = itaconic acid) and [H2N(CH3)2]6Na4[Ln4SeW8(H2O)14(H2PTCA)2O28] [SeW9O33]2·31H2O [Ln = Pr3+ (2), Nd3+ (3)] were obtained by Ln nature control. The primary frameworks of 1-3 are composed of trivacant Keggin-type [B-α-SeW9O33]8- and [SeW4Om]n- [Ln = Ce3+ (1), m = 17, n = 6; Ln = Pr3+ (2), Nd3+ (3), m = 18, n = 8] fragments bridged by organic ligands and Ln clusters. Intriguingly, Ln nature results in the degradation of hexameric 1 to trimeric 2-3. Besides, 1@DMDSA and 3@DMDSA composites (DMDSA·Cl = dimethyl distearylammonium chloride) were prepared through the cation exchange method, which were then reorganized to form two-dimensional (2D) honeycomb thin films by the breath figure method. Using these honeycomb thin films as electrode materials, the aptasensors were further established by utilizing methylene blue as an indicator and cDNA and Au nanoparticles as signal amplifiers to enhance the response signal so as to realize the purpose of ochratoxin A (OTA) detection. This work provides a new platform for detecting OTA and explores the application potential of POM-based composites in biological and clinical analyses.

Highly Reliable Charge Trap‐Type Organic Non‐Volatile Memory Device Using Advanced Band‐Engineered Organic‐Inorganic Hybrid Dielectric Stacks

AbstractWith the recent interest in data storage in flexible electronics, highly reliable charge trap‐type organic‐based non‐volatile memory (CT‐ONVM) has attracted much attention. CT‐ONVM should have a wide memory window, good endurance, and long‐term retention characteristics, as well as mechanical flexibility. This paper proposed CT‐ONVM devices consisting of band‐engineered organic–inorganic hybrid films synthesized via an initiated chemical vapor deposition process. The synthesized poly(1,3,5‐trimethyl‐1,3,5,‐trivinyl cyclotrisiloxane) and Al hybrid films are used as a tunneling dielectric layer and a blocking dielectric layer, respectively. For the charge trapping layer, different Hf, Zr, and Ti hybrids are examined, and their memory performances are systematically compared. The best combination of hybrid dielectric stacks showed a wide memory window of 6.77 V, good endurance of up to 104 cycles, and charge retention of up to 71% after 108 s even under the 2% strained condition. The CT‐ONVM device using the hybrid dielectric stacks outperforms other organic‐based charge trap memory devices and is even comparable in performance to conventional inorganic‐based poly‐silicon/oxide/nitride/oxide/silicon structures devices. The CT‐ONVM using hybrid dielectrics can overcome the inherent low reliability and process complexity limitations of organic electronics and expedite the realization of wearable organic electronics.

Tailoring Stress and Ion-Transport Kinetics via a Molecular Layer Deposition-Induced Artificial Solid Electrolyte Interphase for Durable Silicon Composite Anodes.

Silicon is considered as a blooming candidate material for next-generation lithium-ion batteries due to its low electrochemical potential and high theoretical capacity. However, its commercialization has been impeded by the poor cycling issue associated with severe volume changes (∼380%) upon (de)lithiation. Herein, an organic-inorganic hybrid film of titanicone via molecular layer deposition (MLD) is proposed as an artificial solid electrolyte interphase (SEI) layer for Si anodes. This rigid-soft titanicone coating with Young's modulus of 21 GPa can effectively relieve stress concentration during the lithiation process, guaranteeing the stability of the mechanical structure of a Si nanoparticles (NPs)@titanicone electrode. Benefiting from the long-strand (Ti-O-benzene-O-Ti-) unit design, the optimized Si NPs@70 cycle titanicone anode delivers a high Li+ diffusion coefficient and a low Li+ diffusion barrier, as revealed by galvanostatic intermittent titration (GITT) investigations and density functional theory (DFT) simulations, respectively. Ultimately, the Si NPs@70 cycle titanicone electrode shows high initial Coulombic efficiency (84%), long cycling stability (957 mAh g-1 after 450 cycles at 1 A g-1), a stable SEI layer, and good rate performances. The molecular-scale design of the titanicone-protected Si anodes may bring in new opportunities to realize the next-generation lithium-ion batteries as well as other rechargeable batteries.

Highly Luminescent Inorganic-Organic Hybrids with Molecularly Dispersed Perylene.

A highly photoluminescent material was obtained by the incorporation of perylene into an inorganic-organic hybrid film. Octosilicate, a layered alkali silicate, was modified with a cationic surfactant, dioleyldimethylammonium ion, to accommodate perylene molecularly and uniformly. The perylene-doped dioleyldimethylammonium octosilicate films were fabricated by simply casting the toluene solution of perylene with dispersed dioleyldimethylammonium octosilicate on substrates. Near-unity photoluminescence quantum efficiency was achieved for hybrids containing a high concentration of perylene.

Spin Relaxation Prevention Effect of Optically Pumped Atomic Magnetometer Cell by Room Temperature Molecular Layer Deposition of Inorganic-organic Hybrid Film

Spin Relaxation Prevention Effect of Optically Pumped Atomic Magnetometer Cell by Room Temperature Molecular Layer Deposition of Inorganic-organic Hybrid Film

Preparation and Properties of Organic-Inorganic Hybrid Antireflection Films Made by a Low-Temperature Process Using Hollow Silica Nanoparticles.

Layers made of hollow silica nanoparticles have potential applications as antireflection films with lower refractive index values compared with existing materials such as silica glass (1.50) and magnesium fluoride (1.38). The advantages of such nanoparticles result from interactions between the solid shell, the cavity phase core, and the voids between particles. To obtain practical antireflection films, it is necessary to control the number of layers of these hollow silica nanoparticles and to fill the gaps between particles with a solid. In the present study, antireflection films were prepared by applying a coating of hollow silica nanoparticles dispersed in a UV-curable monomer solution onto plastic substrates. After film formation and exposure to UV light, the voids between the nanoparticles were completely filled with a polymer matrix. Tuning the particle concentration in the coating solution allowed the formation of antireflection films comprising one to three layers of the hollow silica nanoparticles. The reflectance of the films was dependent on the number of layers, and a 100 nm thick film in which two layers of hollow silica nanoparticles were precisely arranged showed the lowest reflectance of 0.92% at 550 nm wavelength, equivalent to a refractive index of 1.23. Because the voids between particles were filled with the polymer, these films resisted contamination during manual handling and so would be expected to maintain low reflectance during practical applications. This work demonstrates that nanosized inorganic–organic hybrid films composed of hollow silica nanoparticles and a UV-curable resin can exhibit optical properties and structural integrity that cannot be achieved by either substance alone.

Solvent coordination engineering for high-quality hybrid organic-inorganic perovskite films

Identifying the structure of iodoplumbate complexes in various solutions is essential for linking the coordination environment of the perovskite precursor to its final properties. In this study, we investigate the structure of methylammonium lead iodide (MAPbI3) perovskite precursor solutions as a function of the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide (DMSO) using X-ray absorption fine structure spectroscopy. It was demonstrated that DMSO modifies the precursor structure at the atomic level. X-ray diffraction, scanning electron microscopy, and UV–Vis spectroscopy analyses showed that the coordination environment of iodoplumbate complexes in precursor solutions is strongly correlated with the morphology of perovskite films. The appropriate amount of DMSO in the precursor solution modifies the Pb-O and Pb-I coordination of iodoplumbate complexes, which could change the growth process of high-crystallization perovskite films. This study sheds light on the formation mechanism of perovskite films from precursor solutions, which will lead to the development of high-quality films and ultimately high-efficiency devices.

Effect of film structure on CH3NH3PbI3 perovskite thin films’ degradation

The instability of CH3NH3PbI3 perovskite hybrid organic–inorganic films is a serious problem, which might be a drawback for their use in solar energy conversion. In this work, we have evaluated the degradation of the perovskite films and studied the influence of film morphology on their degradation. CH3NH3PbI3 perovskite thin films were deposited on glass substrates by a spin coating technique at different centrifugation speeds using different solvents. This study aims to determine the films’ properties that may control the degradation process. This study was based on the comparison between the characteristics determined from XRD analysis and optical transmittance of freshly deposited films and those aged 1 year in ambient air at room temperature and dark conditions. The degradation was manifested by the partial decomposition of the perovskite to PbI2, I2, and metallic lead. The degradation evaluation was achieved by the determination of the variation of the most intense XRD diffraction peak in the freshly prepared film and after aging. The results indicated that the degradation is very sensitive to the films’ porosity and thickness. Reducing the thickness of the film or increasing the porosity enhances the degradation process.

Structure and protective properties of Si-Ti-epoxy organic–inorganic hybrid film

Sol–gel method was used to prepare a Si-Ti-epoxy organic–inorganic hybrid composite sol, which was cured on the carbon steel surface at room temperature to obtain a transparent film. Based on the scanning electron microscopic image, the microscopic morphology of the film is flat, smooth, and dense. The atomic force microscopic image shows a nanometer scale morphology, and the structure of the Si-Ti-epoxy hybrid film is more uniform and denser than that of the Si-epoxy hybrid film. The film/carbon steel attenuated total reflection infrared spectrum presents a Si-O-Fe absorption peak at 831 cm−1, which indicates the chemical bonding of the organic–inorganic hybrid film and the carbon steel substrate. The contact angle of the film is greater than 90°, indicating hydrophobicity. The dense nanostructure of the film and the chemical combination with the metal substrate confer the film with excellent electrochemical protection performance. The low-frequency impedance modulus (|Z|0.01Hz =1010Ω∙cm2) of the Si-Ti-epoxy hybrid film (15–20μm) is an order of magnitude higher than the double-thick epoxy film (30–35μm). The corrosion current density (10−11A/cm2) obtained by the polarization curve is two orders of magnitude lower than the double-thick epoxy film.

Tincone-New Hybrid Organic-Inorganic Anode Material for High Performance Li-Ion Battery

Atomic layer deposition (ALD) is a nanomaterial synthesis method that draws more and more attention in the past few decades. Due to its self-limit growth nature, ALD has become a powerful tool for fabricating uniform and conformal thin film[1]. Molecular layer deposition (MLD), as a derivative of ALD, is a technique specially for organic or organic-inorganic hybrid films. Due to the carbon chains were involved [2], MLD thin film shows several more merits than ALD such as low growth temperature, flexibility and low density, which are very meaningful when applied in battery material. Studies of MLD film in battery field are usually focus on the following aspects. For example, applying MLD film as a post-treatment for electrode. In this way, MLD coating can suppress electrode volume change issue during discharge/charge processes because of its flexibility. [3] Secondly, if added an annealing process, MLD film with organic component would turn into porous carbon/metal oxide matrix. The post-anneal treatment would improve the contact between active material and conductive carbon, and also bring more site for heteroatom doping [4].Although there are lots of studies of MLD film in battery field, only few researchers use MLD film as an organic electrode material. In our study, we synthesised Tincone MLD film on Nitrogen doped carbon nanotube (N-CNT), and test the electrochemical properties of this hybrid organic-inorganic anode material Tincone/N-CNT in Li-ion battery. As a result, Tincone film shows electrochemical activity in CV test, and good lithium storage ability in cycling test. The capacity retention of Tincone/N-CNT is 89% after 100 cycles. As a usage of MLD film for electrode material, Tincone/N-CNT enriches the ways of applying MLD method in battery field as well as energy storage area. Keywords: MLD battery；Tincone；Lithium ions battery

High Performance Lithium Silicide Electrode Enable By Molecular Layer Deposition

The energy demand of our society is increasing without precedents. Lithium-Ion Batteries (LIBs) are and have been an enabler of the present communication revolution; LIBs are the powerhouse of portable communication devices. Consumers are starting to demand more sustainable and more environmentally friendly energy sources, energy production and distribution. To satisfy these demands, the next generation of rechargeable batteries will need higher specific energy and power (per mass) and energy and power density (per volume) than the current generation of LIBs. The current technology uses Lithium Metal Oxide (LMO) as positive electrodes and graphite as a negative electrode. This system has an energy density value ca. 250 WhL-1. To improve the power and energy density of the LIBs devices; new electrode material needs to be developed.Silicon (Si) has become one of the most investigated materials for LIB negative electrodes because of its ability to accommodate 3.75 moles of Li per mole of Si (Li15Si4), leading to a theoretical capacity of 3,579 mA h/g at room temperature1. While 372 mA h/g is the theoretical capacity for graphite2, this material can only accommodate 1 mole of Li per 6 mol of C.Despite Si advantages, progress towards a commercially available Si negative electrode has been impeded by their rapid capacity fade, poor rate capability, and low coulombic efficiency. The cause of electrode degradation is the Si volume change of ~300% upon lithium insertion and extraction3, presenting a major problem for electrochemical performance. The volume fluctuation damages the electrical contact between Si and the current collector, being too large to be controlled by currently developed coating technologies.One of the leading strategies established for the realization of such an approach is coating nano-Si particles with flexible materials to attempt to accommodate the volumetric changes of the particles. In this context, we propose to carry out a surface modification, in which Molecular Layer Deposition (MLD) is utilized to grow a mechanically robust, flexible coating, to undertake the Si expansion and contraction. For it, we have used TiCl4 molecule and as it is a relatively small molecule, when combined with the larger organic reactants, has high growth rates that are mainly limited by steric hindrance caused by the organic reactants. For these reasons, the recipe here developed is based on Glycerol and TiCl4 as the titanium precursor.The composition of the films was studied using Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope-Energy-dispersive X-ray spectroscopy (SEM-EDX). Multiple characteristic absorption modes for both carbon and titanium related groups can be observed in the FTIR spectrum (Figure 1). These techniques confirm that the combination of both the carbon-related groups and the Ti absorptions providing evidence for the successful deposition of a hybrid organic-inorganic film showing that we are able to detect Ti in the surface of the electrode.Cyclic Voltammetry was used to characterize the electrochemical performance of the LixSi negative electrode coated with titanicone. We have successfully shown the deposition of titanicone on LixSi electrode and an initial electrochemical assessment of this electrode. These electrodes exhibit high capacity, around 2,000 mAhg-1 at 0.10C, and 270 mAhg-1 at 20C corroborating the goodness of the proposed methodology.Typical voltammogram shows the formation of the solid electrolyte interface, evident in the first cycle. In the subsequent scans, these peaks disappear (Figure 2). The sample exhibit the regular waves are corresponding to the Si redox reaction. Prosini PP, Cento C, Rufoloni A, Rondino F, Santoni A. A lithium-ion battery based on LiFePO4 and silicon nanowires. . 2015;269:93-97.Ikonen T, Nissinen T, Pohjalainen E, Sorsa O, Kallio T, Lehto VP. Electrochemically anodized porous silicon: Towards simple and affordable anode material for li-ion batteries. . 2017;7(1):7880.Zhao J, Lu Z, Liu N, Lee H, McDowell MT, Cui Y. Dry-air-stable lithium silicide and lithium oxide shell nanoparticles as high-capacity prelithiation reagents. . 2014;5:5088. Figure 1

Study of Novel Hafnium-Based Hybrid Thin Films By Molecular Layer Deposition

Molecular layer deposition (MLD) is a gas-phase reaction technique which relies on self-limiting surface reactions for growth of surface-bound polymers. Hybrid organic-inorganic materials usually possess properties distinct from both inorganic and organic components. MLD techniques can be used to deposit hybrid films with precisely defined composition and tunable properties that can be conformally deposited on high aspect ratio substrate. In this study, novel hybrid organic-inorganic hafnium based polymer films were successfully deposited using sequential exposures of a homoleptic tetrakis(dimethylamido)hafnium (TDMAH) complex and ethanolamine (EA) as the reactants by MLD. Hafnium nitrides and oxides have received much attention in the fields of microelectronics and lithium ion batteries, and thus are of interest as hybrid materials that may impart beneficial mechanical and chemical properties. To grow the Hf hybrid films, TDMAH and EA pulses were alternated with 120s of N2 purge. The processes were investigated as a function of temperature, precursor pulsing time and number of cycles. The results show that the self-limiting surface reactions possess a constant growth rate of ∼1.9 Å per cycle at 120 °C. Temperature-dependent growth characterization was performed for these hybrid materials. By increasing the temperature from 65 °C to 145 °C the growth rate decreases from ∼2.5 Å per cycle to ∼1.1 Å per cycle. The presence of expected C-N, C-O and -CH2 moieties in the MLD films were confirmed by Fourier transform infrared (FTIR) spectroscopy. Hafnium nitride and oxide bonds within hybrid thin films were identified by applying X-ray photoelectron spectroscopy (XPS). The results show that the deposited hafnium based organic-inorganic hybrid films contain both Hf – O and Hf – N bonds which enables flexibility, and thus have potential applications for both battery and microelectronics technologies.

Synthesis of Near-Infrared Mechanoluminescence Material Via Organic Acid-Aided Process

A mechanoluminescence (ML) material is a kind of phosphor. There has been attracting attention as a sensing material capable of two-dimensionally visualizing physical phenomena such as strain, stress, or load [1-5]. In particular, the ML material that emits near-infrared (NIR:0.75~1.0 μm) and short-wave infrared (SWIR:1.0~2.5 μm) luminescence has biological transparency and a wavelength range different from a room illumination and is expected to spread a new applying field [6-7]. To use the ML material for physical sensing technology using an inorganic-organic hybrid film mixed with resin, the diameter of the ML particle needs to be several micrometers or less. However, the ML material is commonly synthesized by a solid-state reaction method at a rather high temperature above 1400°C, resulting in the formation of large particle size. Such a large ML particle is pulverized under a mechanically milling process to reduce the particle size, producing crystal defects. The crystal defects are known to be one of the causes of the charge career trapped sites in the ML material, posing deterioration of the ML intensity as well as a decrease in the reproducibility of sensing characteristics. Thus, to develop an ML material having a high ML intensity, it is necessary to establish a synthetic method capable of lowering the sintering temperature. For a decrease in the sintering temperature of the functional oxides, it has been reported that it is effective to produce a precursor whose particle size and shape are controlled by a solution technique. Although there have been numerous reports regarding the solution technique, an organic acid-aided method is suitable for producing a complicated material with a multi-element composition because it desolvates an aqueous solution and remains all the metal compounds [8]. In the present study, therefore, we tried to synthesize ML material by using the organic acid-aided method and evaluated both optical properties under visible light and near-infrared regions. Among various ML materials reported, we selected SrAl2O4 co-doped with Eu, Cr, and Nd ions (SAOEuCrNd) which emits both NIR and SWIR luminescence [7] and selected malic acid as a representative organic acid. For comparison, SrAl2O4 doped with Eu (SAOEu), SrAl2O4 co-doped with Eu,Cr (SAOEuCr), or Eu,Nd (SAOEuNd) were also synthesized by using the same synthetic method. The synthesized ML materials were evaluated by various analysis instruments.From x-ray diffraction (XRD) patterns of the synthesized ML materials, all the diffraction peaks coincided with those of the monoclinic SrAl2O4 (PDF no. 34-0379). This indicates that monoclinic SrAl2O4 can be synthesized by the organic acid-aided method even by using various luminescent center ions. The photoluminescence (PL) spectra of all the synthesized ML materials exhibited a broad emission which is centered at approximately 520 nm under excitation at 365 nm. On the other hand, Nd-doped ML materials such as SAOEuNd and SAOEuCrNd showed several peaks at around 900, 1100, and 1400 nm under excitation at 365 nm. The PL intensities under NIR and SWIR regions for SAOEuCrNd were much higher than those for SAOEuNd. Logically, it is reasonable to expect that Cr ion behaved as a sensitizer such as an energy transfer mechanism of YAG:Cr,Nd. Finally, we evaluated the ML intensity under NIR and SWIR regions for the synthesized ML materials by using a lab-built system comprising Si image sensor and optical filter (pass long wavelengths >750 nm). As a result, Nd-doped ML materials showed ML response toward the tensile strain and the ML intensity increased with increasing the tensile strain, although there is no luminescence response toward the tensile strain for SAOEu. Especially, SAOEuCrNd exhibited the highest ML intensity. Thus, the SAOEuCrNd synthesized by the organic acid-aided method using metal nitrates and malic acid is a promising candidate for ML materials which emits both NIR and SWIR luminescence.[1] C.N. Xu, T. Watanabe, M. Akiyama, X.G. Zheng, Appl. Phys. Lett., 74(9), 1236 (1999).[2] C.N. Xu, T. Watanabe, M. Akiyama, X.G. Zheng, Appl. Phys. Lett., 74(17), 2414 (1999).[3] A. Yoshida, L. Liu, D. Tu, S. Kainuma, C.N. Xu, J. Disaster Res., 12, 506 (2017).[4] N. Terasaki, Y. Fujio, S. Horiuchi, and H. Akiyama, Int. J. Adhes. Adhes., 93, 40 (2019).[5] Y. Fujio, C. N. Xu, Y. Sakata, N. Ueno, N. Terasaki, J. Alloys Compd., 41, 154900 (2020).[6] D. Tu, C.N. Xu, S. Kamimura, Y. Horibe, H. Oshiro, L. Zhang, Y. Ishii, K. Hyodo, G. Marriott, N. Ueno, X.G. Zheng, Adv. Mater., 1908083 (2020).[7] N. Terasaki, C.N. Xu, WO 2015033648, September 9, 2013.[8] Y. Teraoka, H. Kakebayashi, I. Moriguchi, S. Kagawa, Chem. Lett., 20(4), 673 (1991).