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By continuously varying the structure of graphene oxide paper (PRGP) using Joule heating annealing, we are able to tune its electrical conductivity (σ) and thermal diffusivity (α) in a very wide range: more than three orders of magnitude for σ (186–503009 S/m) and 10-fold for α (8.31 × 10−7 m2/s to 9.31 × 10−6 m2/s). Excellent coherency-linear relationship between σ and α is discovered although they are sustained by different carriers: electrons and phonons. Such coherency exists over two sections: σ > 2 × 104 S/m, and 103

Here, we report a preliminary analysis on the manufacturing and testing of a low-cost and eco-friendly paper-based gas sensors realized with Aerosol Jet Printing (AJP) and Flash Lamp Annealing (FLA). The hygroscopic properties of paper make it possible to detect the presence of water-soluble gases in an environment provided with a relative humidity (RH) above a given threshold $(\text{RH} > 75\%)$ . This aspect allows the usage of such technology in the realization of a future food smart packaging detecting the presence of a malevolent gas like ammonia in food. Carbon interdigitated electrodes were printed and sintered on chromatographic paper, obtaining a mean resistance value of to $(231\pm 20)\ \mathrm{k} \Omega$ and $(249\pm 28)\ \mathrm{k} \Omega$ for the left and the right electrode respectively. The sensors were tested at different relative humidity (RH) values (75, 80, 90, 100%), and once stabilized they were tested with different ammonia concentrations (3, 6, 9 and 12 ppm). A proportional decrease was evidenced in increasing RH and ammonia concentration. Considering the baseline at a constant value of $\text{RH} =75\%$ , the sensors showed a resistance decrease of 15% in presence of the lowest concentration of 3 ppm.

A composite formed of NiO nanoflakes assembled on carbonized filter paper (CFP) has been successfully synthesized by a hydrothermal route with subsequent annealing. The CFP substrate presented a three-dimensional (3D) network structure. The composite electrode demonstrated high capacity and good cyclic and rate capabilities. It delivered a capacity of 724 mA h g−1 at current density of 100 mA g−1 after 100 cycles without apparent capacity fading during cycling. It delivered a capacity of 446 mA h g−1 even at high current density of 1000 mA g−1. The composite achieves better battery performance through ZnCl2 activation compared with conventional HNO3 activation.

Herein, Cu-doped Co-ZIF nanoplate arrays are uniformly grown on a commercial paper towel substrate first. After a subsequent annealing treatment, well-defined Cu-doped Co/CoO nanoparticles embedded in N-doped carbon hybrid nanoplate arrays supported on the carbon paper substrate (denoted as Cu-doped Co/CoO/NC NPAs@CP) are obtained, which exhibit excellent performance as a low-cost, lightweight and binder-free anode for lithium ion storage.

Electrodes for non-enzymatic glucose sensing based on gold nanostructures onto graphene paper (GP-AuNPs) have been obtained inducing dewetting, by laser annealing, of 8 nm-thick Au layer deposited by sputtering. Molten-phase dewetting of gold layer, which produces the formation of spherical nanoparticles (AuNPs), was achieved by nanosecond laser annealing using a pulsed (12 ns) Nd: yttrium aluminum garnet YAG laser operating at 532 nm. The Surface of the electrode presents gold rich regions consisting of graphene nanoplatelets covered by spherical AuNPs. The sizes of AuNPs are in the range of 10–150 nm. Glucose was detected at a potential of 0.17 V vs SCE, which corresponds to the intense peak of two electrons oxidation. Highest sensitivity of 600 µA mM−1 cm−2 of glucose detection was obtained. The resulting sensitivity, detection limit and linear range of glucose detection are very promising since comparable to the actual state of art results for nanostructured gold electrodes which are, however, produced by complex multi-steps processes.

Spinel ferrites are very popular due to their large flexible properties and loss eddy current loss. Among spinel ferrites, Ni-Zn nanoferrites plays vital in industry because of its numerous applications in r due to its high permeability and high mechanical strength. Ni – Zn are very good magnetic materials and its magnetic, electrical and structural properties can be varied by changing ions at tetrahedral and octahedral sites. Ni-Zn nano ferrites papers were studied and summarized the conclusions of different studied by varying synthesis methods, varying shape of nanomaterials, changing dopant, changing sintering temperature and changing annealing temperature.

We study long-term electrochemical sodium and lithium cycling, and tensile testing behavior of thermally reduced graphene oxide (rGO) paper electrodes. We find strong dependence of annealing temperature and gas environment on the electrical conductivity, electrochemical capacity, and rate capability of the electrodes. The effect, however, was opposing for the two cell types. Lithium charge capacity increased with increasing annealing temperatures reaching a stable value of ∼325 mAh·ganode–1 (∼100 mAh·cm–3anode at ∼48 μA·cm–2 with respect to total volume of the electrode) for specimen annealed at 900 °C, while a sharp decline in Na charge capacity was noted for rGO annealed above 500 °C. Maximum sodium charge capacity of ∼140 mAh·g–1anode at 100 mA·g–1anode (∼98 mAh·cmanode–3 at ∼70 μA·cm–2) was realized for specimen reduced at 500 °C. These values are the highest reported for GO paper electrodes. More important, annealing of GO in NH3 environment resulted in a complete shutdown of its Na-ion cyclability s...

Fully printed and flexible inorganic electrolyte gated transistors (EGTs) on paper with a channel layer based on an interconnected zinc oxide (ZnO) nanoparticle matrix are reported in this work. The required rheological properties and good layer formation after printing are obtained using an eco-friendly binder such as ethyl cellulose (EC) to disperse the ZnO nanoparticles. Fully printed devices on glass substrates using a composite solid polymer electrolyte as gate dielectric exhibit saturation mobility above 5 cm2 V&minus, 1 s&minus, 1 after annealing at 350 &deg, C. Proper optimization of the nanoparticle content in the ink allows for the formation of a ZnO channel layer at a maximum annealing temperature of 150 &deg, C, compatible with paper substrates. These devices show low operation voltages, with a subthreshold slope of 0.21 V dec&minus, 1, a turn on voltage of 1.90 V, a saturation mobility of 0.07 cm2 V&minus, 1 and an Ion/Ioff ratio of more than three orders of magnitude.

Polyvinylidene difluoride (PVDF) piezoelectric sensors were manufactured on a paper-based substrate using Aerosol Jet Printing to print silver interdigitated electrodes and the photopolymer NOA 81 to obtain restraining walls for PVDF. Silver traces were sintered thanks to Flash Lamp Annealing, a low-thermal exposure process to avoid damages to the paper substrate. The samples were printed on a 3D cellulose-based substrate. Electrical capacitance measurements showed a mean value of 2.58 pF after Ag printing, to a mean value of 4.07 pF after PVDF deposition and poling. Different masses were employed, ranging from 50 to 500 g, during tests assessing a linear behavior of the sensors when loaded. A maximum voltage peak value of 11.9 V was reached at a mass of 500 g. These preliminary results appear to be promising for the realization of a complete paper-based impact/force sensor to be applied in packaging.

Reduced graphene oxide paper was fabricated by incorporating dopamine. By using adhesive property, reducing ability, high thermal stability, and high carbon-yielding characteristic of dopamine, the dopamine-embedded graphene oxide paper can be mechanically stronger, thermally more stable, and electrically more conductive compared to conventional graphene oxide paper. Herein, in order to preserve a planar structure of graphene sheets and obtain free-standing paper, a simple one-step fabrication method was introduced, in which vacuum-assisted filtration of a graphene oxide suspension and polymerization of dopamine proceed at the same time. The manufactured paper had sequentially layer-stacked and planar structure of graphene sheets and polydopamine. The paper showed increased tensile strength and elongation, and higher thermal stability. Electrical conductivity was recovered, which was not measurable in conventional graphene oxide paper. To investigate enhancement of reduction, thermal annealing was further carried out. As a result, a critical reduction temperature was lowered and higher electrical conductivity was recorded at all annealing temperatures.

We report the fabrication of flexible conductive graphene paper through a direct and gentle annealing process of graphene oxide paper. Thermal treatments at 700 °C under argon or hydrogen atmosphere directly applied to parent graphene oxide paper lead to a significant removal of disruptive oxygen-containing functional groups, and to a considerable recovery of the sp2 network structure. Detailed comparison of chemical and combined chemical–thermal treatments by scanning electronic microscopy (SEM), Raman, X-photoelectron spectroscopy (XPS) and conductivity measurements underline the high efficiency of the direct annealing process. The resulting highly reduced graphene oxide paper exhibits electrical conductivities as high as 8100 S/m representing an increase of five orders of magnitude with respect to the parent graphene oxide paper, which significantly outperforms the results of chemical treatments. Moreover, our direct and gentle thermal reduction allows maintaining the structural integrity and mechanical flexibility of the parent graphene oxide paper thus overcoming problems of brittleness typically encountered in annealing processes. Our approach sets the base for an easy, cost-effective and environmentally friendly fabrication route for flexible conducting graphene paper of great application potential as flexible electrodes in various fields of technology.

We demonstrate edge electron emission from flexible free-standing graphene paper (GP). The turn-on field is measured at 2.2 V/ $\mu{\rm m}$ , and the maximum emission current density at 3 ${\rm A}/{\rm cm}^{2}$ . The field emission properties of GP can be optimized by adjusting the thickness and annealing temperature. Because it is flexible, it can be shaped into different forms to meet the requirements of specific applications. The electron beam shape can range from a sheet electron beam to a cylindrical (hollow) electron beam.

A graphene-based porous paper made of multilayer graphene (MLG) microsheets is developed for application as a flexible electrically conducting shielding material at radio frequency. The production process is based on the thermal expansion of a graphite intercalated compound, the successive liquid-phase exfoliation of the resulting expanded graphite in a proper solvent, and finally the vacuum filtration of the MLG-suspension using a nanoporous alumina membrane. Enhancement of the electrical conductivity and electromagnetic shielding properties of the MLG paper is achieved by gentle annealing at 250 °C overnight, and by mechanical compression at 5 MPa. The obtained results show that the developed MLG papers are characterized by an electrical conductivity up to 1443.2 S/cm, porosity around 43%, high flexibility, shielding effectiveness up to 55 dB at 18 GHz with a thickness of 18 μm. Numerical simulations are performed in order to understand the main factors contributing to the shielding performance of the new material.

Ti ion implantation with different doses was used to modify the surface and deoxygenate graphene oxide (GO) papers. The morphologies, microstructures and surface chemical states of the modified GO papers were investigated. Based on the results, the surface amorphization of GO papers is realized by Ti ion implantation. In addition, the whole GO paper is reduced or deoxygenated, which can be attributed to the annealing effect. However, at a low implantation dose of 5 × 1016 cm−2, the deoxygenation of GO paper is found to be incomplete. With a high implantation dose of 3 × 1017 cm−2, a surface composed of whirlpool-like structures is generated, while the layer-by-layer stacking structure of the as-prepared GO paper is retained.

Hydrogen is considered a potential future energy source. Among other applications of hydrogen, hydrogen-rich water is emerging as a new health care product in industrial areas. Water electrolysis is typically used to generate a hydrogen rich water system. We annealed 10AA carbon paper in air to use it as an electrode of a hydrogen rich water generator. Driven by annealing, structural changes of the carbon paper were identified by secondary electron microscope analysis. Depending on the various annealing temperatures, changes of the hydrophilic characteristics were demonstrated. The crystal structures of pristine and heat-treated carbon paper were characterized by X-ray diffraction. Improvement of the efficiency of the electrochemical oxygen evolution reaction was measured via linear voltammetry. The optimized annealing temperature of 10AA carbon paper showed the possibility of using this material as an effective hydrogen rich water generator.

A technique for obtaining gas sensor samples from graphite paper with a nanotube film is described. Current-induced annealing of the graphite paper and additional evaporation of a nanotube graphite film in a hydrogen atmosphere are combined in the developed technique. The current−voltage characteristics of the samples have been measured at room temperature in air, in vacuum, and at low concentrations of NH3, ethanol, and acetone. Experiments demonstrate that these samples containing carbon multiwall nanotubes can be used as a gas sensor to detect the presence of NH3 and acetone. They are characterized by high sensitivity and selectivity, fast response, restoration, and stability of the characteristics. The estimated sensor sensitivities to NH3, acetone, and ethanol at a current of 96.8 mA are ~15, ~12, and ~1 mV/Torr, respectively. Their sensitivity is determined by the difference in the behavior of their current−voltage characteristics under exposure to NH3, ethanol, and acetone. The sensor features fast response (5–20 s) and restoration (within 5 min, restoration to the initial state before the exposure to NH3 is 100.2%), as well as the stability of its characteristics (the pressure ranges from 1 × 10–6 to 760 Torr).

Crystalline ZnO rods rooted on manifold carbon nanofiber (CNF) paper were synthesized via electrodeposition of ZnO onto electrospun CNF paper (∼300 μm thick) followed by oxidative annealing. The morphology of the ZnO deposited on the conductive CNF paper can be tailored to be polycrystalline rods with convex-shaped ends at a high Zn2+ precursor concentration (0.5 mM) upon annealing (denoted CZ-a-0.5, where “a” refers to annealing), whereas the sample electrodeposited at a low Zn2+ precursor concentration (0.25 mM) results in single crystalline rods with concave-shaped ends (denoted CZ-a-0.25). In order to systematically examine the photocatalytic activity, the annealed and non-annealed CNF/ZnO samples (CZ-a and CZ, respectively) were compared for the oxidation of phenol (one-electron transfer reaction), the production of H2 via water splitting and H2O2 production via oxygen reduction (both two-electron transfer reactions). Irrespective of the type of reaction, the CZ-a samples exhibit superior photocatalytic activities than the CZ samples in the following order: CZ-a-0.25 > CZ-a-0.5 > CZ-0.5 > CZ-0.25. The observed activity order is consistent with the trend observed in the XRD intensity ratio between the (100) and (002) planes (i.e., I100/I002 ratio) of the corresponding samples. The time-resolved photoluminescence decay spectra further reveal that the average lifetime of charge carriers is the shortest for CZ-a-0.25, followed by CZ-a-0.5, CZ-0.5 and CZ-0.25, which is consistent with the trends in the I100/I002 ratio and the photocatalytic activity. The growth mechanism of the samples and the key factors determining the photocatalytic activity are discussed. Finally, the detailed surface characterization of the samples is described.

article i nfo Sintering of printed metal nanoparticles can be made not only by conventional heating, but also by, e.g., elec- trical, microwave, plasma, laser and flash lamp annealing. We demonstrate sintering by using low-cost incan- descent lamps as an effective way of obtaining highly conductive contacts of two types of ink-jet printed metal-nanoparticle inks on paper; both alkanethiol protected gold nanoparticles and a commercially avail- able silver nanoparticle ink. This low-cost roll-to-roll compatible sintering process is especially suitable on paper substrates because of the high diffuse reflectance, relatively high thermal stability and low thermal conductivity of paper. A volume resistivity of around 10 μΩ cm was achieved of the inkjetted silver nanopar- ticles within 15 s of exposure to an IR lamp, which corresponds to a conductivity of 10-20% of that of bulk silver. Too long exposure time and too high intensity, however, lead to darkening of the paper fibers. Both the crack formation and the coffee ring effect of the inkjet printed gold nanoparticles were, furthermore, found to be reduced on paper as compared to glass or plastic substrates.

The article describes an efficient method for the preparation of silver nanoparticles ink for its application in printed electronics. The effective formulation using polyvinylpyrrolidone (PVP) and triethylamine leads to highly stable silver nano-ink. The spincoated silver nanoparticulate films fabricated using the as-prepared nano-ink exhibit bulk-like conductivity at moderate annealing temperature of 60C -100C. Additionally; pen-on-paper type of conventional writing is successfully demonstrated with modifying the formulation of such nano-inks. The viscosity of as-prepared Ag nano-ink can be easily altered by varying the concentration of binders and solvents to suit its end applications. Such flexibility coupled with high conductivity and amphiphilic nature makes this silver nano-ink highly useful in various advanced printing techniques. Copyright © 2016 VBRI Press.

Sputter deposited IGZO films usually require an annealing process over 300°C for activation. This annealing process limits the use of various flexible substrates. To overcome this drawback, we propose low-temperature activated IGZO TFTs by simultaneous UV & thermal (SUT), electrical assisted thermal (EAT), and high pressure annealing (HPA) methods.

Nano-coating has become the focus of study in recent years because of its wide range of applications in several fields to obtain superior materials. By depositing a thin film with thickness ranging from nanometer to micrometer, an advanced material is developed. These advanced materials have properties like ultraviolet (UV) protection, self-cleaning properties, photocatalyst properties, and thermal resistance as well as thermal conductivity, higher reflectivity and transparency, wear resistance, and much more. All these properties depend upon the target materials used for the process and the formation of films. By obtaining a proper deposition process of selective target material, an enhanced component in the field of energy optimization, biological implants, mechanical instruments and tools, and thermal resistive surfaces that will have superior properties can be developed. These properties of an advanced material depend upon the chemical characteristic of the target material, the thickness of the film deposited, grain size and grain orientation, and surface morphology as a few of the important factors. In this review paper, the studies carried out by different scientists on titanium oxide as a target material to study the wettability properties, optical properties, and effect of annealing on wettability, effect of the phase of titanium oxide on wettability, and effect of UV irradiation on wettability have been reviewed. Different deposition processes, such as a physical deposition process as well as a chemical deposition process, have been considered.

We propose a novel annealing technique in order to improve the dark characteristics for CMOS image sensor without deteriorating the transistor characteristics. Microwave annealing (MWA) has been studied as an alternative annealing technique for diffusion-less dopant activation and implantation damage recovery in advanced CMOS technology. We employed MWA technique in order to recover crystalline defects in CMOS image sensor (CIS) process. We demonstrate that MWA can be implemented a low thermal budget to obtain the effect of repairing the ion-implantation damage equivalent to conventional furnace annealing (FA). MWA can repair the process damage without transistor performance degradation by additional thermal treatment. MWA is promising technique for repairing crystalline defects in high performance image sensing devices with high frame rate, low power and excellent dark characteristics..

Recently it has been shown that FePd alloys can be encapsulated in graphitic carbon based systems for a better particle dispersion through addition of dichloro-cyclooctadiene palladium to ferrocene. Here we propose an advanced two-stage method which allows the synthesis of very thick deposits of planar rolled-like graphite structures filled with FePd3 alloys as dominant product in the entire reactor. The first stage is used to pyrolyze the Pd-containing hydrocarbon on the top of Si/SiO2 substrates for Pd deposition while the second stage is used for the evaporation and pyrolysis of the Fe-containing precursor (ferrocene) for the FePd alloy formation and encapsulation. Annealing studies also show that no changes in the unit cell of the FePd3 structure are found even after tens of hours at 600–650 °C under Ar/H2 flow. Instead a change in the encapsulated particle shape and spatial arrangement is found. The samples are characterized in detail through scanning and transmission electron microscopy, energy dispersive X-rays, Raman spectroscopy, thermogravimetric analyses, X-ray diffraction and room-temperature magnetometry.

One-dimensional (1D) nanostructures aligned on a conductive substrate are advantageous for various energy applications. In this work, we report the synthesis of hierarchically nanostructured NiO nanotube arrays supported on carbon fiber paper (CFP) via a simple ZnO-template method and evaluated the arrays as supercapacitor electrodes. We demonstrate that subtle changes in the annealing temperature during the preparation of NiO affect the porous structures of both NiO and CFP, which synergically enhance the pseudocapacitive performance of NiO according to in-depth electrochemical analyses.

We introduced a strategic "Kinetic Diffusion Multiple" (KDM) that undergoes interdiffusion annealing followed by realistic thermal treatment. The blended spectra of phases and microstructures subjected to treatment in deeply grooved composition gradients enables the microstructure and micromechanical properties of structural materials to be surveyed by high-spatially resolved micro-analysis along the composition arrays. The KDM was demonstrated as a robust high-throughput methodology that enables rapid screening of the composition-microstructure-micromechanical/properties relationships for different metallic materials. It has also proven great success at elucidating the lasting effects of alloying elements and diffusion flux on microstructure, micromechanical properties, phase transformation, and their interrelationships as a whole., This work was supported by the Natural Science Funds of China [Grant No. 51571113], International S&T cooperation Program of China (2015DFA51430) and the Joint Project of Industry-University-Research of Jiangsu Province [Grant No: BY2016005]. CW, NL and JW are grateful to the China Scholarship Council (grant number: 201406290011; 201506020081; 201506890002) for financial support. Yi Chen would like to thank the Natural Science Foundation of Jiangsu Province (Grant No. BK20160291) and the National Natural Science Foundation of China (Grant No. 51601077) for the financial support. The

In the present study, reduced graphene-oxide (r-GO) papers were prepared by vacuum filtration method using chemically obtained graphene oxide as raw materials. Different reduction methods, chemical, thermal or the combination were designed to investigate the influence of reduction process on the structure and conductivity of r-GO papers. The reducibility of the obtained papers was investigated by XPS and Raman. The structure, morphology and electrical conductivity were examined by XRD, SEM and four point resistivity test system, respectively. Results showed that chemical reduction using hydrazine or annealing in reducing ambinent alone was not sufficient to achieve maximum reduction, the highest C/O ratio and highest conductivity was obtained in paper reduced via a combination of hydrazine and thermal annealing treatment. In order to further improve the conductivity of the paper, Ag nanoparticles have been decorated into the paper.

A new carbonization process is here proposed for the production of highly conductive, self-standing Li-ion battery electrodes. In such a procedure, the paper electrodes obtained as shown in Chap. 6 (i.e., with truly natural microfibrillated cellulose as binder and a cellulose sheet as support) are treated at 600 °C in a furnace under nitrogen flux. In this way, both the MFC fibres and the FB sheet get carbonized; the resulting electrodes, despite decreased mechanical characteristics which nevertheless do not fully jeopardize their hand ability, demonstrate significantly higher electronic conductivity, since the binding network composed by insulating MFCs turns into conductive carbonaceous fibres upon annealing. Moreover, the cellulose handsheet support gets converted into a conductive carbon-paper sheet which can serve as embedded current collector to rapidly transfer the electrons to the external circuit. In the course of this chapter the carbonization procedure will be described and the effective prospects of this method will be demonstrated in increasing the performance of paper electrodes, as a result of the highly increased electrochemical performances and, in particular, the power output which allows to use this carbonised paper electrodes in more power demanding applications.

Novel approaches including combustion synthesis achieved via both spin-coating/post annealing and spray-coating/in-situ annealing can be used to generate high-quality metal oxide thin films, including IGZO, and high performance metal oxide TFTs at relatively low temperatures. Furthermore, we demonstrate metal oxide TFTs using proprietary solution-processed dielectric and passivation layers.

A straightforward photo-annealing approach was developed for building functional polymer layers on paper. Conducting polyaniline with the ability for photothermal conversion can be readily annealed by near-infrared light. The annealed polymers become both insulating and hydrophobic. Selective photo-annealing produces a functional layer with patterned conductive arrays. This material exhibits real-time response to ammonium gas. Complete photo-annealing preserves the porous structure but changes the wettability of the polyaniline-nanofiber film.

While carbon fiber paper (CFP) has been widely used in batteries, fuel cells, and supercapacitors, its effect on device performance can be rather complicated. In this study, we examined the effect of CFP from different batches on the performance of a CFP-supported MnOx hybrid supercapacitor (CFP/MnOx). It is found that the contribution of the MnOx to the capacitance is dominating if the MnOx coating on CFP is dense and conformal, but becomes much less significant if the MnOx coating on CFP is porous or non-conformal. This is because annealing CFP/MnOx at 400 °C in air is necessary to obtain proper MnOx phases for high capacitance; the annealing process may increase the specific surface area of CFP if it is not fully covered by MnOx. Also, the etching of carbon surface weakens the attachment of MnOx to CFP and worsens the electrical connection of MnOx to CFP, further reducing the contribution of MnOx to capacitance. Finally, much to our surprise, it is found that the properties of the CFP varied from batches to batches, which critically influence the MnOx coating morphology/density. These factors in turn greatly affect the contribution of each component to the capacitance of the CFP/MnOx hybrid supercapacitors.

We report combined electrochemical double-layer capacitance (EDLC) and pseudocapacitance in reduced graphene oxide (rGO) thick film like paper due to annealing temperature variations. The influence of annealing temperature (from room temperature (RT) to 1000 °C) on the structural, morphological, electrical, and electrochemical properties of rGO paper was evaluated. Upon increasing the annealing temperature, shifting of the dominant (002) X-ray diffraction (XRD) peak to a higher degree, volume expansion, and red-shifting of the G band in Raman spectra were observed. High-resolution transmission electron microscopy (HRTEM) images showed a reduction in the interlayer distance in rGO sheets from 0.369 to 0.349 nm as the annealing temperature increased from RT to 1000 °C; these results were congruent with the XRD results. According to X-ray photoelectron spectroscopy (XPS), the presence of hydroxyl, carboxyl, and other oxygen-containing groups decreased in samples annealed at higher temperatures. The attached functional groups, the electrical conductivity, and the supercapacitance of rGO papers were found to be mutually interrelated and could be tuned by varying the annealing temperature. The rGO paper annealed at 200 °C in a 1 M H2SO4 electrolyte at a scan rate of 50 mV s−1 exhibited a maximum specific capacitance of 198 F g−1.

The effects of the reduction process and carbon nanotube (CNT) content on the supercapacitive behavior of electrodes made from flexible, binder-free thick graphene oxide (GO) papers are studied. It is found that the supercapacitive performance depends on several factors, including the presence of oxygenated functional groups after reduction, the interlayer spacing of the GO papers and their wettability with electrolyte. A moderate reduction of GO papers using hydrazine or annealing at a low temperature of 220 °C in air is proven to be more beneficial to achieve a high capacitance than the heavy reduction using a hydrazine vapor or a high temperature thermal treatment. The addition of a small amount of CNT, typically 12.5 wt.%, to form thick GO/CNT sandwich papers gives rise to an excellent specific capacitance of 151 F g−1 at a current density of 0.5 A g−1, as well as a retention ratio of 86% of the initial value after 6000 charge/discharge cycles at 5 A g−1. These improvements arise from the synergistic effects of the increased electronic conductivity and effective surface area associated with large electrochemical active sites due to the presence of intercalated CNT.

Monodispersed Au nanoparticles are synthesized on the surface of exfoliated graphene nanoplatelets (GNP) in the presence of polyethyleneimine (PEI) with microwave assisted heating. A highly structured layered Au/GNP "paper" with good flexibility and mechanical robustness is prepared by vacuum assisted self-assembly. The thermal and electrical conductivity of the hybrid paper with and without the Au nanoparticles are investigated after different experimental processing conditions including thermal annealing and cold compaction. Annealing effectively decomposes and removes the adsorbed PEI molecules and improves thermal contact between Au/GNP particles, whereas cold compaction reduces porosity and induces stronger alignment of the Au/GNP within the hybrid paper. Both approaches lead to improvement in electrical and thermal conductivity. It is also found that adjacent GNP particles are electrically connected by the Au nanoparticles but thermally disconnected. It is believed that phonons are scattered at the Au/GNP interfaces, whereas electrons can tunnel across this interface, resulting in a separation of electron and phonon transport within this hybrid paper.

Amorphous oxide semiconductor InGaZnO (a-IGZO) thin films were deposited on glass and sapphire substrates using RF magnetron sputtering at room temperature. H2 annealing effect on the electrical conduction, optical transmittance, and structural properties of a-IGZO films has been systematically studied. Temperature-dependent electrical conductivity of a-IGZO films exhibited n-type degenerated conduction behavior in the range of 10–300 K. Electrical properties of the films do not fit with variable range hopping carrier transport model. Optical transmission of a-IGZO films has been enhanced by H2 annealing at elevated temperatures. Fourier-Transform Infrared Spectroscopy analysis indicated formation of O-H bonding state in H2-annealed a-IGZO films which is thermally stable up to 300°C. Electron concentration of a-IGZO films decreases with annealing temperature above 300°C resulting from the reduced H incorporation from OH absorption.

We present electrical and structural features of solution-processed ZnO thin-film transistors (TFTs) grown via a chemical solution process post-treated by ultra violet (UV) annealing step at processing temperature below 250°C. The transfer curves for the UV annealed ZnO TFTs, including around two-order higher on-current magnitude reveals only a negative drift of −0.66 V in time for 15 days, compared with a −9.29 V negative drift of the conventionally thermally annealed ZnO TFTs at 300°C. The observation of X-ray photoelectron spectroscopy clearly demonstrates the significant reduction of non-lattice oxygen vacancies via proper UV annealing step. The nature of improved stability in the UV-annealed ZnO TFTs is also described.

In this study, we reported the capability of a new composition oxide TFTs, fabricated using sputtering process and successfully developed including sputtering target with single-phase. In order to compare single-phase target with multiphase target, as-deposited films by same sputtering condition for sputtering process were prepared and the chemical characterization of target, as-deposited film, and annealed films, respectively by using EPMA and ICP analyses were evaluated. Single-phase target had a uniform and homogeneous metal composition distribution without segregation. In addition, after annealing process, the films were maintained the chemical composition. We, therefore, selected single target and evaluated the electrical performances. The saturation mobility (μsat) was measured to be 22.4 cm2V−1s−1. In addition, threshold voltage (Vth) was 0.75 V and subthreshold swing (SS) was 0.44 V/decade, respectively. This study could encourage in developing a novel composition oxide TFTs with high mobility.

Here, we report a general route to form high-performance and stable solution-processed metal-oxide TFTs and circuits at room-temperature by deep-ultraviolet (DUV) photochemical activation The photo-enhanced DUV annealing induces condensation and densification of amorphous metal-oxide semiconductor films via photochemical reactions and film microstructure modifications by energetic photons. It was found that the photochemical annealing is effective in fabricating most metal-oxide semiconductors and the metal-oxide TFTs typically demonstrate comparable or even better electrical performance and operational stability with high-temperature (≥350C) annealed devices. The room-temperature fabricated metal-oxide TFTs and circuits have shown field-effect mobilities of more than 14 and 7 cm2 V−1 s−1 on glass and polymeric substrates, respectively. The fabricated 7-stage ring oscillators on polymeric substrates indicate oscillation frequency of > 340 kHz corresponding to propagation delay of < 210 ns per stage.

Low resistance Ohmic contacts using Ti/Au metallization on n-type amorphous indium zinc oxide (IZO) (n∼5×1020 cm−3) deposited on paper substrates are reported. The minimum specific contact resistivity of 8×10−7 Ω cm2 was achieved on IZO films both as-deposited and for annealing temperatures of up to 125 °C. The contact resistance increased to 4×10−6 Ω cm2 at 175 °C. The sheet resistance was found to vary from 24 to 17 Ω/sq, and the transfer resistance was ∼0.045 Ω mm for the as-deposited and low temperature annealed samples. The contact resistance was independent of measurement temperature, indicating that field emission plays a dominant role in the current transport. Such Ohmic contacts achieved with little or no annealing are important for paper based electronics requiring low temperature processing (

Simple and effective preparation methods for highly stacked graphene papers are presented by site-selective functionalization of graphene oxides with di-functional small molecules, 1,4-butandiol and ethylenediamine. It was found that hydroxyl groups of 1,4-butandiol react mostly with edges of graphene oxides, while more reactive amine groups of ethylenediamine can react with carboxylic acid and epoxy groups on both edges and basal planes, which results in the interconnected graphene morphology in aqueous media. The graphene papers fabricated from the functionalized graphene oxide suspensions show a well stacked layer structure with a smaller interlayer distance than that of unmodified graphene oxide papers. Furthermore, high temperature annealing enhances the electrical conductivities of graphene papers fabricated from graphene sheets linked by ethylenediamine as high as 1716 S cm−1, due to the better stacked structure, further graphitization, and N-doping effects.

We have been applying a low discharge voltage (Ca, Mg)O protective layer to plasma display panels (PDPs) to reduce their power consumption. However, (Ca, Mg)O is highly reactive with CO2, and the resulting carbonate formation during high-temperature panel sealing in air impairs the low discharge voltage characteristic. We investigated the mechanism of the carbonation reaction that occurs on a (Ca, Mg)O surface during annealing in air at 450°C and found that the CO2 diffuses through the formed CaCO3 layer and that a (Ca, Mg)O + CO2 r CaCO3 + MgO reaction then occurs. This carbonation reaction evidently stops when the growing MgO finally forms a layer at all boundaries between the CaCO3 and (Ca, Mg)O regions.

We investigated the photo-response of a-IGZO thin films under light illumination. The photo-response was compared before and after annealing. As the annealing temperatures increase, photo-response changes quite substantially. We explored the photo-responses of a-IGZO thin films under light illumination with various wavelengths. The photo-responses involve the photo-excitation and the dark relaxation phenomena in a-IGZO thin films. The photo-responses of samples were monitored and analyzed in terms of the trap states and oxygen vacancies. The quite large change of photo-response by the annealing was analyzed in terms of trap states and oxygen vacancies.

We report fabrication of mechanically bendable touch sensor pads by direct stamping of nanoinks with silver nanoparticles (AgNPs) dispersed in an organic solvent. Direct stamping lowers annealing temperature of silver nanoparticles and enhances mechanical flexibility. The directly stamped silver electrode reaches the silver nanoink's final conductivity at lower annealing temperature, 130 °C, than the As-sprayed silver electrode. And also the directly stamped silver electrodes have much lower resistance than the As sprayed one even before annealing of AgNPs. In addition, the touch sensor pads fabricated by direct stamping shows no significant decrease in sensitivity even after repeated bending stroke test at 1 Hz for 10 000 cycles. These results of mechanical stability and low annealing temperature are possible because the compressive force, which is applied to the AgNPs inside the trenches of a stamp during the direct stamping process, induces removal of pores between neighboring AgNPs, and subsequent, densification of the layers of AgNPs.

A photo-responsive multi-bilayered film consisting of azobenzene polymer liquid crystals (PA6Az1) and poly(vinyl alcohol) (PVA) has been prepared on a glass substrate by alternate spin coating of the polymer solutions. The reflectivity of the multi-bilayered film disappears by annealing at 80 °C. The disappearance of the reflection by the annealing is related to the thermal out-of-plane molecular orientation of PA6Az1 even in the multi-bilayered film, which leads to a very small difference in refractive indices between PA6Az1 and PVA. The reflectance of the multi-bilayered film is increased again by UV irradiation because of the transformation from the out-of-plane orientation to an in-plane random orientation. In this way, on-off switching of the reflection is achieved by combination of the thermally spontaneous out-of-plane molecular orientation and following photoisomerization of PA6Az1 comprising the multi-bilayered film.

Conductive flexible hydrogel composites were printed on paper substrates using a functional ink, which was designed and formulated for screen-printing. The inks were prepared using abundant and eco-friendly materials by blending carbon fibers into the matrix of a water-soluble cellulose derivative, carboxymethyl cellulose. For an optimal concentration of carbon fibers (10 wt.%), the printed patterns exhibit a sheet resistance of around 300 Ω/sq without any post-printing annealing process. The resistance of the screen-printed hydrogel patterns is sensitive to variations on relative air humidity through moisture adsorption and swelling of the cellulosic matrix surrounding the carbon fibers. It was found that the sensitivity to temperature and humidity can be triggered by drying the printed patterns at 120 oC. A negative temperature coefficient thermistor with a sensitivity of 0.079 oC-1 at 25 oC and a hygristor, where a variation in the RH from 10 to 60 % increases the resistance by 15 times, were screen-printed on paper using the formulated cellulose/carbon fibers based ink.

Atomic layer deposited (ALD) HfO"2/GeO"xN"y/Ge(100) and Al"2O"3/In"0"."5"3Ga"0"."4"7As(100)-4x2 gate stacks were analyzed both by MOS capacitor electrical characterization and by advanced physical characterization to correlate the presence of electrically-active defects with chemical bonding across the insulator/channel interface. By controlled in situ plasma nitridation of Ge and post-ALD annealing, the capacitance-derived equivalent oxide thickness was reduced to 1.3nm for 5nm HfO"2 layers, and mid-gap density of interface states, D"i"t=3x10^1^1cm^-^2eV^-^1, was obtained. In contrast to the Ge case, where an engineered interface layer greatly improves electrical characteristics, we show that ALD-Al"2O"3 deposited on the In"0"."5"3Ga"0"."4"7As (100)-4x2 surface after in situ thermal desorption in the ALD chamber of a protective As cap results in an atomically-abrupt and unpinned interface. By avoiding subcutaneous oxidation of the InGaAs channel during Al"2O"3 deposition, a relatively passive gate oxide/III-V interface is formed.

The work addresses the occurrence of Ge dangling bond type point defects at Ge"xSi"1"-"x/insulator interfaces as evidenced by conventional electron spin resonance (ESR) spectroscopy. Using multifrequency ESR, we report on the observation and characterization of a first nontrigonal Ge dangling bond (DB)-type interface defect in SiO"2/(100)Ge"xSi"1"-"x/SiO"2/(100)Si heterostructures (0.27=

We have studied Fermi level pinning (FLP) of Hf-based high-k gate stacks based on thermodynamics based on an O vacancy model. Our study shows that FLP cannot be avoided when the system is under thermal equilibrium. O exposure to aim O vacancy elimination is not effective, since O vacancy elimination condition is equivalent to the Si substrate oxidation which leads to the increase in Equivalent oxide thickness (EOT). We also studied the mechanism of FLP induced by the reduction with H"2 anneal. FLP with H"2 anneal is governed by the O vacancy annihilation reaction by reducing SiO"2 interface layer. Based on these considerations, we propose some recipes for obtaining band-edge-work-function metals.

We fabricated 350°C low temperature solution-processed zinc tin oxide thin film transistors by employing H2O wet annealing, which is considerably lower than widely used 500°C. We have optimized 350°C H2O wet annealing condition to achieve good electrical characteristics such as threshold voltage and saturation mobility.

In this article, we describe the effect of ethanolamine (EA) surface treat-ment on the inverted InP quantum dot light-emitting diodes (QD-LEDs) with inorganic metal oxide layers. The efficiency of the inverted QD-LEDs was significantly enhanced by EA treatment and optimization of the ZnO annealing temperature.