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3D printing technologies using photo polymerization of photo-curable monomer and oligomers as an organic binder have been studied to fabricate ceramics with a complicated shape. For minimizing distortion of ceramics during the manufacturing process and fast 3D printing of ceramic green body, high mechanical strength of ceramic green body and fast photo polymerization of the photo-curable resin are required, respectively. In this study, the ceramic green bodies with various compositions were fabricated by photo radical polymerization of the slurry-type resin composed of fused silica bead, and tri- or (and) mono-functional acrylate. Photo radical polymerization behaviors of mono-, tri-functional acrylate monomer, and blend of two monomers were analyzed by photo-DSC and FT-IR measurements. The structure analysis of photo-cured polymers made by each monomer was performed by thermo-mechanical analysis. Through mixing of mono- and tri-functional acrylate monomer, we confirmed that polymerization rate more increased compared with those of only mono-, tri-functional monomer. Unreacted vinyl groups in the polymers prepared with blend of two monomers decreased by an addition of mono-functional monomer in tri-functional monomer. The polymers prepared with the blend showed higher storage modulus and broader viscoelastic behavior compared to those fabricated with tri-functional monomer. Thus, to achieve high fracture strength of the green body, we verified that the photo-cured polymer in the green body should have high crosslinking density and low free volume based on reduction of unreacted vinyl groups in the polymer. Additionally, through analysis of cross-sectional SEM of the green body, we confirmed that acrylate monomer should include proper content in the slurry-type resin to maximize the fracture strength of the body regardless of the type of the used acrylate monomer. This was because low content of acrylate monomer in the slurry-type resin makes it difficult to form neckings composed with photo-cured polymers between the silica beads.

Tailoring the crystal orientation of poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has attracted widespread interest because of its effects on the ferroelectric properties required for...

In this study, we introduce the horizontal centrifugal casting (HCC) process that enables centrifugal force-assisted, scalable production of large-area (10 in.) polymer composite films based on nanocellulose (CNF) and nanochitin (ChNF). The HCC employs a cylinder mold with its rotation pivot being in a horizontal posture to harness centrifugal force to help flatten the film being cast, from which polymer composite films with excellent uniformity and flatness can be reliably produced in the size of the lateral surface of the cylinder mold. The combination of centrifugal force and horizontal layout of cylinder mold can allow reliable fabrication of large-area self-standing films from both polymeric solution and/or suspension in a scalable and simple fashion, which is a task not readily achieved in common film-forming techniques, such as solvent casting and vacuum filtration. We demonstrate such reliability and versatility of the HCC process by fabricating typical biocomposite films out of both a solution blend of ChNF/silk fibroin and a colloidal suspension of CNF/nanoclay as well as investigating their processing-structure-property relation as an optically transparent composite film targeting for structural component for flexible green optoelectronics and fire-retardant film, respectively.

Transparent cellulose nanofiber (t-CNF) films were prepared by succinylation and an aqueous collision counter system treatment, and used for the colorimetric detection of diethyl chlorophosphate (DCP), a nerve agent mimic in the vapor phase. DCP receptor with an oxime residue was anchored on the surface of succinylated CNF films, resulting in the target probe (CNF-Azo films). CNF-Azo films exhibited selective detection behavior toward DCP in the vapor phase. The oxime groups of CNF-Azo film reacted with DCP upon exposure to DCP vapor, which was accompanied by a color change from yellow to purple. Significantly, the film's transparency was preserved throughout the detection process, allowing it to identify objects behind the film during DCP detection. This property could apply to any detection system in which the color change caused by detection does not interfere with the film's transparency. The CNF-based film sensor was biodegradable, allowing it to be disposable after use.

Despite recent substantial advances in perovskite materials, their 3D integration capability for next-generation electronic devices is limited owing to their inherent vulnerability to heat and moisture with degradation of their remarkable optoelectronic properties during fabrication processing. Herein, a facile method to transfer the patterns of perovskites to planar or nonplanar surfaces using a removable polymer is reported. After fabricating perovskite devices on this removable polymer film, the conformal attachment of this film on target surfaces can place the entire devices on various substrates by removing this sacrificial film. This transfer method enables the formation of a perovskite image sensor array on a soft contact lens, and in vivo tests using rabbits demonstrate its wearability. Furthermore, 3D heterogeneous integration of a perovskite photodetector array with an active-matrix array of pressure-sensitive silicon transistors using this transfer method demonstrates the formation of a multiplexed sensing platform detecting distributions of light and tactile pressure simultaneously.

Metal nanowires (NWs) are promising transparent conducting electrode (TCE) materials because of their excellent optoelectrical performance, intrinsic mechanical flexibility, and large-scale processability. However, the surface roughness, thermal/chemical instability, and limited electrical conductivity associated with empty spaces between metal NWs are problems that are yet to be solved. Here, we report a highly reliable and robust composite TCE/substrate all-in-one platform that consists of crystalline indium tin oxide (c-ITO) top layer and surface-embedded metal NW (c-ITO/AgNW-GFRH) films for flexible optoelectronics. The c-ITO top layer (thickness: 10-30 nm) greatly improves the electrical performance of a AgNW-based electrode, retaining its transparency even after a high-temperature annealing process at 250 °C because of its thermally stable basal substrate (i.e., AgNW-GFRH). By introducing c-ITO thin film, we achieve an extremely smooth surface (

Tailoring the crystal orientation of poly(vinylidene fluoride

Herein, we report on a transparent, water-stable, high oxygen barrier packaging film made from a combination of cellulose nanofiber (CNF) and a fluoropolymer (FP) coating. Nanofibrillation of the hardwood kraft pulp was carried out using succinic anhydride pretreatment and aqueous counter collision (ACC) technique to obtain ultrafine (5–7 nm) succinylated cellulose nanofibers (SCNF), which was readily fabricated into a thin coating (on PET film) as well as a self-standing film. Introducing the FP topcoat on SCNF enabled a synergistic enhancement of both oxygen barrier performance and stability against water-swelling.

Natural biological composites often couple light weight with tunable and spatially controlled mechanical properties including stiffness, toughness, and hardness. Examples include the toughness of seashells, the hardness of the chiton tooth, and the stiffness gradient of the squid beak. While seashells and the chiton tooth have a mineralized inorganic component, the squid beak is entirely organic. The squid beak is known as one of the hardest fully organic materials. The hydrated squid beak has a large stiffness gradient from soft, at the interface with the squid mouth, to hard at the tip. This gradient occurs from the spatially controlled cross-linking of chitin nanofibers with a protein matrix aided by catecholamines. Here, we introduce a water processable deacetylated chitin composite with tunable mechanical properties from spatially controlled cross-linking assisted by catecholamines. Given the natural abundance of chitin and the ease of water processing, this composite can find applications for bridging mechanically mismatched materials.

Since the conventional fluorine-based electro-active polymers release toxic residues into the environment during their syntheses and decomposition processes, eco-friendly piezoelectric polymers are urgently demanded in the field of energy-related soft materials. Here, we derive a high-performance biodegradable chitin polymer from squid pen material and demonstrate its utility as a flexible piezoelectric material. The readily controlled ferroelectric chitin film confers excellent piezoelectricity under external mechanical pressure, resulting in comparable performance with that of conventional fluorine-based piezoelectric polymers. In particular, the sufficient piezoelectric behavior in chitin film allows us to not only realize a high-fidelity paper-type speaker and microphone that operates over a wide frequency range without significantly deteriorating the input and output sounds but also demonstrate transparent speaker consisting of AgNWs electrodes onto freestanding chitin film which also enables to resemble the original sound. Finally, the biodegradable chitin polymer can be successfully dissolved by chitinase enzyme within eight days without any toxic residues remained.

Flow-electrode capacitive deionization (FCDI) has been studied for its ability to perform continuous deionization; however, there are no reports on the degradation of the desalting performance of FCDI under short-circuited closed cycle operation (SCC) mode. In this study, we observed a gradual decrease in FCDI desalting performance and weight increase of the flow-electrode under SCC mode, which mixes the cathode and anode flow-electrodes. Through an analysis of NaCl and water accumulation rates obtained from the weight variation of the flow-electrode, the gradual decline in the desalting performance was caused by a decrease in the content of activated carbon (AC) with ion adsorption sites in the flow-electrodes. This was driven by water transfer from the feed stream to the flow-electrodes through the ion exchange membrane attributed to hydrated ions and osmosis. We calculated the salt adsorption capacity (SAC) and salt adsorption rate (SAR) based on the variable weight of the flow-electrode. The maximum SAC (mSAC) and average SAR (ASAR) values of the FCDI were higher and lower than those of conventional capacitive deionization systems, respectively. This was likely due to the repetitive use of the flow-electrode and long ion transport pathways in the flow-electrode, respectively.

Among non-fluorinated ferroelectric polymers, odd number Nylons have recently attracted attention because of their solution-processibility and decent ferroelectric characteristics. Here, we demonstrate a ferroelectric and piezoelectric Nylon-11 δ` phase crystal film manufactured via a humidity modulated casting and subsequent melt-quenching process. The low relative humidity (RH) below 20% during the spin casting process effectively mitigates the formation of hygroscopic holes resulting in the formation of pin-hole free Nylon-11 thin films. In addition, the subsequent melt-quenching gives rise to the evolution of the ferroelectric δ` phase crystals, which is carefully confirmed by grazing incidence X-ray diffraction and infrared spectroscopy measurements. The resulting ferroelectric thin films show decent remnant polarization of ~4.6 μC/cm2 at a low operating voltage of ±30 V, suggesting the formation of high-quality Nylon-11 δ` phases thin film. Furthermore, the centrifugal casting at low RH facilitates the fabrication of freestanding and transparent 20-μm thick ferroelectric δ` phase film after the subsequent melt-quenching process. The resulting Nylon-11 film provides excellent piezoelectric performance upon external vertical pressure, which enables a proof-of-concept demonstration as a Morse code detector.

Herein, we report a new version of a bioinspired chitin nanofiber (ChNF) transparent laminated composite film (HCLaminate) made of siloxane hybrid materials (hybrimers) reinforced with ChNFs, which mimics the nanofiber-matrix structure of hierarchical biocomposites. Our HCLaminate is produced via vacuum bag compressing and subsequent UV-curing of the matrix resin-impregnated ChNF transparent paper (ChNF paper). It is worthwhile to note that this new type of ChNF-based transparent substrate film retains the strengths of the original ChNF paper and compensates for ChNF paper's drawbacks as a flexible transparent substrate. As a result, compared with high-performance synthetic plastic films, such as poly(ethylene terephthalate), poly(ether sulfone), poly(ethylene naphthalate), and polyimide, our HCLaminate is characterized to exhibit extremely smooth surface topography, outstanding optical clarity, high elastic modulus, high dimensional stability, etc. To prove our HCLaminate as a substrate film, we use it to fabricate flexible perovskite solar cells and a touch-screen panel. As far as we know, this work is the first to demonstrate flexible optoelectronics, such as flexible perovskite solar cells and a touch-screen panel, actually fabricated on a composite film made of ChNF. Given its desirable macroscopic properties, we envision our HCLaminate being utilized as a transparent substrate film for flexible green optoelectronics.

Here, we introduce regenerated fibers of chitin (Chiber), the second most abundant biopolymer after cellulose, and propose its utility as a nonwoven fiber separator for lithium metal batteries (LMBs) that exhibits an excellent electrolyte-uptaking capability and Li-dendrite-mitigating performance. Chiber is produced by a centrifugal jet-spinning technique, which allows a simple and fast production of Chibers consisting of hierarchically aligned self-assembled chitin nanofibers. Following the scrutinization on the Chiber–Li-ion interaction via computational methods, we demonstrate the potential of Chiber as a nonwoven mat-type separator by monitoring it in Li–O2 and Na–O2 cells.

Here, we report on the synthesis of a silica nanoparticle (NP)-reinforced oligosiloxane nanohybrid material (SM-nanocomposite) and demonstrate its properties as a robust transparent hard coating material for various applications. The oligosiloxane (MMO) resin as a matrix was synthesized using methyl and methacryl silanes via a hydrolytic sol-gel condensation. The silica NPs with various sizes (12, 20 and 60 nm) as nanofillers were also synthesized through a hydrolytic sol-gel condensation, and the surface of NPs was organically modified with methyl and methacryl functions, which allowed stable dispersion and chemical cross-linking of the NPs with MMO matrix. In this work, we introduce synthetic steps of the nanocomposite and discuss the optical, morphological, thermal and mechanical properties of the composite.

For a lithium–oxygen (Li–O2) battery air electrode, we have developed a new all-in-one platform for designing a porous, carbon-free conducting nanopaper (CNp), which has dual functions as catalyst and current-collector, composed of one-dimensional conductive nanowires bound by a chitin binder. The CNp platform is fabricated by a liquid diffusion-induced crystallization and vacuum filtration methods. Employing less than 1 wt % chitin to connect the conductive skeleton, pores and active sites for reactions have become maximized in self-standing CNp. The carbon-free CNp enables the Li–O2 air electrode to be more stably operated compared to carbon nanofibers and other CNps bound by PVDF and PMMA; side reactions are largely suppressed on the CNp. The versatile chitin is highlighted for diverse conducting nanopapers that can be used in various applications.

Recently, there has been growing interest regarding electrostatic discharge (ESD) failures of semiconductors in electronic devices. A system-level ESD test method based on the IEC61000-4-2 standard is widely used today. There is a need, however, for testing the ESD immunity of a solid-state drive (SSD) itself. Drive-level ESD test can reduce system dependencies and development time. In this paper, ESD failure mechanisms were divided into radiation and conduction, and the drive-level ESD test based on the radiation failure mechanism is proposed. A transmission line pulse (TLP) was used to produce a rectangular pulse containing high frequency components and a radio frequency (RF) coupler was used to apply an electric field and a magnetic field simultaneously to the SSD. This new method avoids the directivity issues of conventional field probes. Four Serial Attached SCSI (SAS) protocol SSDs and four disk array enclosures (DAE) were used to verify the new method. It is confirmed that there is a strong correlation between the drive-level ESD test and the system-level ESD test. It is expected that it can help to determine the liability of internal parts in case of ESD failure.

As components or products become more reliable, the failure by electro static discharge (ESD) is getting one of the most important problems. In the past, ESD was recognized as a system-level problem. However, it has recently been recognized as a component-level problem such as dynamic random access memory (DRAM) and solid state drive (SSD). It is difficult to assess the system-level ESD risk for the components being developed. In this paper, component-level ESD test method is developed using transmission line pulse (TLP) to assess ESD immunity of IC products. In addition, it is verified that ESD immunity of ICs correlated with ESD immunity in system-level. Therefore, system-level ESD performance for the components being developed can be predicted using the new component-level ESD test method. This results in reduced development costs for both system and components.

Here, we report on the synthesis of a silica nanoparticle (SNP)-embedded urethane acrylate (UA) nanohybrid material (SNP-UA) and demonstrate its performance as photo-patternable transparent hard coating for optical applications. The SNP (10–20 nm) were synthesized via a base-catalyzed sol-gel condensation and the surface of SNP was chemically modified with methyl and methacryl organic functions by simple and mild solution processes, which not only enabled complete dispersion of SNP in the UA matrix but also rendered chemically cross-linked hybrid network of the SNP-UA. As an UV-curable optical hard coating, the SNP-UA exhibited excellent optical transparency coupled with a tunability of refractive index, good anti-scratch performance, and photo-patternability.

In this paper, we report flexible transparent conducting electrode (TCE) film using a silver grid (Ag grid)/silver nanowire (AgNW) hybrid structure (AG/NW-GFRHybrimer). The AG/NW-GFRHybrimer consists of an AgNW-embedded glass-fabric reinforced plastic film (AgNW-GFRHybrimer) and an electroplated Ag grid. The AgNW-GFRHybrimer is used as a flexible transparent substrate and a seed layer for electroplating. The Ag grid is fabricated via an all-solution-process; the grid pattern is formed using conventional photolithography, and Ag is deposited through electroplating. The AG/NW-GFRHybrimer exhibits excellent opto-electrical properties (transparency = 87%, sheet resistance = 13 Ω/□), superior thermal stability (250 °C for 720 min and 85 °C/85% RH for 100 h), and outstanding mechanical flexibility (bending radius = 1 mm for 2000 cycles). Finally, a touch-screen panel (four-wire resistive type) was fabricated using the AG/NW-GFRHybrimer to demonstrate its potential for use in actual optoelectronic applications.

We report a high-performance, flexible and robust metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using an electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded on the surface of a glass-fabric reinforced composite substrate (GFRHybrimer). The monolithic composite structure of our transparent conducting film allows simultaneously high thermal stability (24 h at 250 °C in air), a smooth surface topography (Rrms < 1 nm) and excellent opto-electrical properties. A flexible touch screen panel (TSP) is fabricated using the transparent conducting films. The flexible TSP device stably operates on the back of a human hand and on a wristband.

One of the key breakthroughs enabling flexible electronics with novel form factors is the deployment of flexible polymer films in place of brittle glass, which is one of the major structural materials for conventional electronic devices. Flexible electronics requires polymer films with the core properties of glass (i.e., dimensional stability and transparency) while retaining the pliability of the polymer, which, however, is fundamentally intractable due to the mutually exclusive nature of these characteristics. An overview of a transparent fiber-reinforced polymer, which is suggested as a potentially viable structural material for emerging flexible/wearable electronics, is provided. This includes material concept and fabrication and a brief review of recent research progress on its applications over the past decade.

In the event of failure to control interference from parts to antennas, the mobile systems cannot perform properly. Also, the EMI certification tests cannot be passed. An effective way to reduce the EMI radiation from components is using a metallic shield can, but it does not meet the demands of miniaturization and flexibility trends in recent mobile devices. A conformal shield package that can compensate for the weakness of shield can is being used more and more. In this paper, the shield effect by applying the conformal shield on package was investigated. For accurate measurement, EMI jig was designed and conformal shield packages were prepared using a silver spray method. Using a near field scan method, the effects of conformal shield packages were investigated. After reducing the contact resistance, the Magnetic field radiation of LP4x was improved by more than 10 dB in all frequency bands. It is founded that the contact resistance management is very critical to ensure uniform EMI characteristics of the conformal shield packages.

An ultraviolet (UV) transparent and stable methyl-siloxane hybrid material was prepared by a facile sol-gel method. The transparency and stability of a UV-LED encapsulant is an important issue because it affects UV light extraction efficiency and long-term reliability. We introduced a novel concept for UV-LED encapsulation using a thermally curable oligosiloxane resin. The encapsulant was fabricated by a hydrosilylation of hydrogen-methyl oligosiloxane resin and vinyl-methyl siloxane resin, and showed a comparable transmittance to polydimethylsiloxane (PDMS) in the UVB (∼300 nm) region. Most remarkably, the methyl-siloxane hybrid materials exhibited long-term UV stability under light soaking in UVB (∼300 nm) for 1000 h.

Presented herein is an optically transparent glass-fabric-reinforced hybrimer film (350-GFRHybrimer film) featuring a low coefficient of thermal expansion (12–14 ppm/°C) and high-temperature processability (350°C). The 350-GFRHybrimer film was fabricated with glass-woven fabrics as reinforcement, and a highly thermally stable siloxane hybrid resin as a matrix. To confirm the potential of the 350-GFRHybrimer film as a flexible substrate, 350°C-processed oxide thin film transistor arrays are demonstrated on the 350-GFRHybrimer film.

The incorporation of ethylene glycol (EG) into a high-k aluminium oxide gate dielectric layer was achieved by a solution process, leading to a distinct increase in the mobility of indium oxide TFT. Frequency-dependent capacitance originating from residual EG was examined and the accompanying effects on indium oxide TFT were studied.

The ability of bioelectronic devices to conduct protons and other ions opens up opportunities to interface with biology. In this research highlight, we report on our recent efforts in bioprotonic devices. These devices monitor and modulate a current of protons with an applied voltage. Voltage-controlled proton flow mimics semiconductor devices with complementary transistors or biological behaviors such as synaptic-like memories and enzyme logic.

We report a flexible high-performance conducting film using an embedded copper nanowire transparent conducting electrode; this material can be used as a transparent electrode platform for typical flexible optoelectronic devices. The monolithic composite structure of our transparent conducting film enables simultaneously an outstanding oxidation stability of the copper nanowire network (14 d at 80 °C), an exceptionally smooth surface topography (R(rms)2 nm), and an excellent opto-electrical performances (Rsh = 25 Ω sq(-1) and T = 82%). A flexible organic light emitting diode device is fabricated on the transparent conducting film to demonstrate its potential as a flexible copper nanowire electrode platform.

We report on the performance of an all-in-one flexible hybrid conducting film employing a monolithically embedded AgNW transparent electrode and a high-performance glass-fabric reinforced composite substrate (AgNW-GFRHybrimer film). Specifically, we perform in-depth investigations on the stability of the AgNW-GFRHybrimer film against heat, thermal oxidation, and wet chemicals to demonstrate the potential of the hybrid conducting film as a robust electrode platform for thin-film optoelectronic devices. With the ease of large-area processability, smooth surface topography, and robust performance stability, the AgNW-GFRHybrimer film can be a promising platform for high-performance optoelectronic devices.

Chitin nanofibers are structural components of the insect cuticle, the exoskeleton of crabs, and mollusk shells. Chitin nanofibers have found broad use in biomedical applications. Here, we study structure-properties-processing relationships of 3 nm chitin nanofiber networks self-assembled from a chitin hexafluoroisopropanol solution.

An easy-to-use tuberculosis skin test is developed with chitin microneedles that deliver purified protein derivative at the correct skin depth and result in a positive test in BCG-immunized guinea pigs.

It is well known that the system-level ESD tests suffer from poor reproducibility. Reproducibility problems appear in various cases; in different systems and the different ESD guns, even if the ESD test conducted using the same systems and ESD guns. This paper is proposed the method which can improve the reproducibility of the system-level ESD test at the same system. The operating state of DRAM is very important factor to the ESD failure level by measuring the signals of memory modules during an ESD event. The soft failure is observed when there is a signal toggling during an ESD event. Through the experiment of program workload, it is confirmed there is a strong correlation between the program workload and the reproducibility of ESD test result. The reproducibility of the system-level ESD test can be improved by maximizing the program workload.

System-level ESD test is conducted into laptop using three different ESD generators. It is observed there is a large variation in ESD test result even if the same ESD generator is used. The current waveform from the ESD generator is a unique individual characteristic varies depending on ESD gun manufacturers and it can result in a different ESD test result. The effect of the current waveform is analyzed by comparing waveforms in frequency domain. Apart from current waveform, direct radiation and second radiation are important factors to induce the system-level ESD failure. The influences of the direct and second radiation on ESD test are analyzed by a shield effect experiment. In order to prevent the ESD failure due to the direct and second radiation, system manufacturers should design their structure as well-shielded by an anti-static case.

A transparent paper made of chitin nanofibers (ChNF) is introduced and its utilization as a substrate for flexible organic light-emitting diodes is demonstrated. Given its promising macroscopic properties, biofriendly characteristics, and availability of the raw material, the utilization of the ChNF transparent paper as a structural platform for flexible green electronics is envisaged.

Reinforcing transparent electrodes with a nanowire mesh brings solar cells that can wrap around objects one step closer to production. Indium tin oxide (ITO) is a rarity among metal oxide crystals – it is optically transparent and conductive enough to serve as electrodes in flat-panel displays and solar cells. Byeong-Soo Bae from the Korea Advanced Institute of Science and Technology and co-workers have now discovered how to make ITO into 10-nanometre-thin, flexible electrodes using a resin embedded with metal nanowires. Normally, the high temperatures needed to produce ITO crystals degrade flexible polymer substrates. But the nanowires impart sufficient mechanical strength to keep the electrodes pliant after ITO heat treatment. Depositing perovskite-type crystals onto the electrodes enabled the researchers to fabricate bendable solar cells with power conversion efficiencies of 12-14%.

Organic/inorganic hybrid materials (hybrimers) were fabricated by the photocationic polymerization of sol–gel-derived cycloaliphatic epoxy oligosiloxane (CAEO)/oxetane blends. The CAEO/oxetane blends showed faster photocationic polymerization rates compared to a CAEO resin. The CAEO/oxetane hybrimers showed a high crosslinking density and flexibility with the addition of oxetane monomer. The increased crosslinking density improved the insulation properties and lowered their dielectric constant. The CAEO/oxetane hybrimer with a substantial thickness of 2 mm showed high transparency (>90%) in the visible range. On the basis of these properties, the CAEO/oxetane hybrimers could be applied to various applications, including optics and display fields. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Novel fluorine-doped zinc tin oxide (ZTO:F) thin-film transistors (TFTs) have been fabricated using an aqueous solution process. Exploiting hydrolysis and condensation reactions in an aqueous solution process, organic-free ZTO:F thin films were fabricated at a low temperature of 250 °C. The fabricated TFT device shows a field-effect mobility of 2.85 cm2/V s, on-to-off current ratios exceeding 107, and sub-threshold swings of 0.83 V/dec. The ZTO:F TFT also displays high operational stability of ΔV th = 1.73 V despite incorporation of a large amount of fluorine and use of a low-temperature annealing process. This is attributed to effective passivation of oxygen vacancy diffusion by metal fluoride bonds at the ZTO:F channel/gate dielectric interface.

We report a transparent moisture barrier coating fabricated with a silica nanoparticle-embedded organic/inorganic hybrid (S–H) nanocomposite. We used a photo-curable, cyclo-aliphatic epoxy based hybrid material (hyrimer) as the matrix and a solvent-less, monodisperse silica nanoparticles as the reinforcement responsible for creating tortuous diffusive path for moisture penetrants. The S–H nanocomposite barrier coating exhibits a single layer WVTR of 0.24 g/m2 day (Ca-test) and an optical transparency of 90% in the visible range. The performance of the barrier coating was also verified in an OLED lifetime measurement test, in which an OLED encapsulated with an S–H nanocomposite barrier coating showed significantly extended lifetime.

A high thermal-stable methacrylate-silicate hybrid nanocomposite (hybrimer) was fabricated based on UV-induced polymerization of a highly-condensed methacryl-oligosiloxane resin (Hy-MO). The Hy-MO resin was newly synthesized via an acid-catalyzed hydrolytic sol–gel reaction of 3-(methacryloxy) propyl trimethoxysilane (MPTS) and diphenyldimethoxysilane. The basic properties of Hy-MO were compared with a conventional resin prepared by a Ba(OH)2·H2O-catalyzed non-hydrolytic sol–gel reaction of MPTS and diphenylsilanediol (N-MO). It was found that Hy-MO have a higher siloxane condensation degree, larger molecular size and weight than the N-MO due to the highly mobile proton ions that effectively catalyze the overall sol–gel reaction. The resultant Hy-MO hybrimer showed a higher thermal stability than N-MO hybrimer.