bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Nano Composite Platforms: Synthesis and Biological Applications Including Cancer Diagnosis
Authors: Packirisamy M 
Published: February 2020

Nanometal-polymer composite films are hybrid materials with inorganic nanoparticles immobilized and uniformly dispersed into a polymer matrix. Nanoparticles such as gold and silver, used to enhance the optical properties of the polymers, are called `optically effective additives` as they lead to new functionalities of the polymer based materials. Au (Ag)-polymer and copolymer composite films are suitable for applications such as waveguides, color filters, thermo-chromic materials etc. The strong plasmon band of Au and Ag nanoparticles (Localized Surface Plasmon Resonance) in the visible spectrum, that originates from the excitation of plasmons by the incident light, makes noble metal-polymer nanocomposites particularly adequate for sensing and biosensing applications. Furthermore, association of Au and Ag nanoparticles of various shapes with poly(dimethylsiloxane) (PDMS), allows the use of nanocomposite materials for microfluidic biosensing as well.
In this presentation, we will talk about the in-situ synthesis of Au-PDMS and Ag-PDMS nanocomposites both at the macroscale and inside the channel of a microfluidic chip. The in-situ synthesis of nanoparticles involves the reduction of gold ions in a gold precursor solution by the curing agent of the polymer. The kinetics of the reaction has been investigated and the effect of annealing temperature on the morphology of nanoparticles has been studied by using imaging and spectroscopic methods. The nanocomposite has been successfully used for sensing of antibody-antigen interactions, allowing the detection of various important proteins. Nanocomposies of metals integrated into other polymers such as PMMA, PVA, and PS have been synthesized as well by using UV, microwave and thermal reduction methods.
The effect of the particle`s shape on the properties of nanocomposites and their sensing abilities has also been studied by synthesizing nanostar particles and integrating them into microchannels.
Because of the biocompatibility and non-toxicity of gold and silver nanoparticles, their nanocomposites can be used for plasmonic detection of biological entities in cancer research.
(Invited) Inkjet Printing of Impedance Sensors for Living Tissues Monitoring
Authors: Bernasconi Roberto , Meroni Davide , Aliverti Andrea , Magagnin Luca 
Published: February 2020

One of the most promising techniques recently applied to minimally invasive living tissues analysis is electrical impedance spectroscopy (EIS). This methodology is able to determine the state of the cells present in an organ by measuring variations in the impedance recorded between electrodes placed in contact with them [1]. The advantages of this approach with respect to invasive techniques like biopsy or others can be immediately individuated: no need to perform surgery on the patient, fast response, easiness and low cost. Moreover, by using EIS, different states (involving for example metabolic toxicity, perfusion loss or cancer development) can be reliably determined.
Typically, EIS is performed placing electrodes directly inside the tissue of interest. The most convenient way to do this is by inserting microneedles containing the electrodes through the skin and directly into the target organ. Moreover, microneedles can be used also to deliver drugs in case of need [2]. For this reason, current research is focusing deeply on the development of microneedles characterized by the highest possible biocompatibility and the lowest invasivity. Interesting examples of micromachined needles exist in literature [3], but they all make use of standard microfabrication techniques with limited flexibility and high cost during the fabrication process.
In the present paper, we discuss the production of EIS microneedles by inkjet printing coupled with electrodeposition. Both these techniques are more flexible than current state-of-the-art methodologies like lithography or sputtering. The shape of the devices is inspired to existing microneedle EIS sensors [3] and adapted to inkjet printing. To produce the sensors, SU-8 is printed to form a mask for the electrodes on a copper substrate. Pt is subsequently electrodeposited selectively inside the mask to form conductive tracks and planar electrodes for EIS. SU-8 is then inkjet printed on the electrodes to form the structural part of the sensor. Finally, the device is flipped and SU-8 is inkjet printed to form a mask on the surface of the sensor able to isolate the tracks from the sensing electrodes. At the end of the manufacturing process, sensors are characterized from the morphological and functional point of view.
[1] P. Heroux, M. Bourdages, Ann. Biomed. Eng. 22(3), 328-337 (1994)
[2] Y.C. Kim, J.H. Park, M.R. Prausnitz, Adv. Drug Deliv. Rev. 64(14), 1547-1568 (2012)
[3] M. Tijero et al., Biosens. Bioelectron. 24, 2410-2416 (2009)
(Invited) Stationary Phase Coatings for a Microfabricated GC Column Integrated with Low Power Ion Trap Mass Spectrometer for Analysis of Volatile Organic Compounds
Authors: Chang Tzu-Hsuan , Struk Daniel , Navaei Milad , Doroshenko Vladimir M. , Laiko Victor , Moskovets Eugene , Novoselov Konstantin , Dimandja Jean-Marie D. , Hesketh Peter J 
Published: February 2020

Miniature gas chromatography (GC) columns of length 6m were fabricated in silicon using eutectic bonding to achieve a column with improved temperature control. The micro GC column includes an integrated platinum thin film heater and temperature sensors for closed loop temperature programing. In order to achieve low power operation the GC column was mounted inside the vacuum chamber of an ion-trap mass spectrometer. This approach provides much lower power consumption than a laboratory instrument. The ion trap electronics were miniaturized and operate at lower power, to demonstrate a portable instrument able to operate at with less than 25W, including vacuum pumps. This instrument will have a range of applications from environmental monitoring, to food safety and medical diagnostics, including breath analysis.
Static coating of the stationary phase in the microfabricated column was carried out by injection using a solvent and extraction at reduced pressure to improve resolution. This paper reports the results of different stationary phases investigated to separate mixtures of volatile organic compounds, specifically OV-1 and OV-215. The properties of the stationary phases where characterized using a novel probe mixture for microcolumn evaluation and six McReynolds probes to identify the Kovats indices and the polarity of the column. The dependence of polarity on the coating technique and temperature of the column during analysis was also investigated. Results are presented with both an FID and ion-trap mass spectrometer to achieve rapid temperature programmed analysis of mixtures of up to 18 organic compounds.
Vertically Aligned Laminate Porous Electrode: Amaze the Performance with a Maze Structure
Authors: Li Xianfeng , Zhang Hongzhang , Yu Ying 
Published: February 2020

The innovation of electrode structures has been lagging far behind that of materials, hampering the industrialization process of high performance batteries. Especially for thick electrodes with high active materials loadings, it’s inadequate to achieve satisfactory performance, especially working at higher current densities, due to the restricted ion transport rate across the electrodes with traditional densely packed structure [1]. To solve the above issue, a vertically aligned laminate porous structure is designed and fabricated for the first time [2]. It seems to cut the thick electrode into thousands of slices vertically arranging like a maze in the X-Y plane, leaving thousands of straight slits (working as ions transport channels) in the Z axis direction. As a result, the electrolyte composition in the slits keeps similar to that on the surface of the electrodes, ascribe to the really large mass effective diffusivity in these slits with lowest tortuosity. Then the real ions transport resistance only exists in the slices, which is much smaller than traditional thick electrodes.
The as proposed maze-like electrode structure (MLPE) is realized by a scalable freeze casting process. Electrodes with such novel structure have shortened ion diffusion channels to rapidly supply electrolyte for reaction and significantly increase active materials loading. The capacity at 2C of Li-S is increased by 50% compared to electrodes directly drying (447mAh g-1). In addition, electrodes with 8 mg cm−2 sulfur can also be easily prepared and show excellent cycling stable at 0.1C (initial discharge capacity: 949 mAh g-1, capacity retention: 98.2%). What’s more, capacities of 89 and 115 mAh g-1 at 10C have achieved for LiFePO4 (LFP) and NaTi2(PO4)3 (NTP) electrodes, respectively, which is over 70% and 130% compared to their contrast with active substances loading of 8.8 and 5.5 mg cm−2.
Fig. a) Schematic illustration of MLPE. b) Schematic illustration of ion transport in the MLPE. c) Rate performance of MLPE-S. d) Cycle performance of MLPE-S. e) Rate performance of MLPE-LFP. f) Rate performance of MLPE-NTP.
References
[1] Y. Yu, H. Zhang, X. Yang, Y. Chen, Z. Jia, J. Yan, H. Zhang, X. Li, J. Mater. Chem. A, 2018, 6, 24066
[2] Y. Yu, H. Zhang, X. Yang, J. Gou, X. Tong, X. Li, H. Zhang, Energy Storage Materials, doi.org/10.1016/j.ensm.2018.09.016

Figure 1
Electrical Characterizations of Amorphous Silicon Carbide
Authors: Geramifard Negar , Joshi-Imre Alexandra , Cogan Stuart F. 
Published: February 2020

Introduction: Emerging applications involving electrical stimulation and recording of nerve employ highly dense thin-film multielectrode arrays fabricated on flexible polymer substrates. Several failure mechanisms including the degradation of encapsulation and interlayer delamination have been identified in multilayer thin-film neural devices. A number of materials such as silicon oxide and silicon nitride have been used enhance the insulation hence increasing the density of the circuits; however, the incompatibility to biological environment, low breaking down field strength and frequency dependence behavior impede the use of these materials for bio applications. In this research, we report on the use of amorphous silicon carbide (a-SiC) which is a biocompatible insulator for electrical components and its electrical characterization in the metal insulator metal(MIM) capacitors.
Materials and Methods: Different thicknesses of amorphous SiC (100-500 nm) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) was sandwiched between two metal layers (TiAuTi 40,300,40nm thick) to create MIM capacitors. Metal layers were deposited by e-beam evaporation and patterned using thin film photolithography techniques. Studies involved current leakage measurement of insulator between two metal electrodes, current-voltage measurement and dielectric constant measurement using parametric test systems.
Tests and Results: In Current-Voltage (I-V) measurement method, voltage was swept from 0-40V with a rate of 50mV/s and current response was accordingly recorded to find the breaking down field potential. Resistivity of material for different thicknesses have been calculated to be around 5e12 ohm.cm ([Fig. A] comparable to silicon nitride), in addition, a low leakage current in the order of picoamp in electric potential of 0.125MV/cm was measured indicating reliability of a-SiC insulation property. Furthermore, dielectric constant of a-SiC was calculated from the capacitance-voltage and capacitance-frequency measurements [Fig. B] showing a linear behavior over the frequency of 0.1 MHz to 10 MHZ which is an indicator of great insulation within biological recording-stimulation frequency range.
Conclusion: We have fabricated a-SiC based MIM capacitor and studied its electrical properties and achieved a comparable dielectric constant with a high resistivity to commonly used materials. The data suggests that a-SiC is a promising candidate for encapsulating highly dense electrical circuits for bioapplication and compatible to thin film microfabrication. Future work will include additional chemical characterization of a-SiC using FTIR to assess the long term chemical stability of this insulator.

Figure 1
Room Temperature Atomic Layer Deposition of ZnO Observed By in Situ IR Absorption Spectroscopy
Authors: Yoshida Kazuki , Saito Kentaro , Miura Masanori , Kanomata Kensaku , Hirose Fumihiko 
Published: February 2020

Zinc oxide (ZnO) is an attractive material for flexible electronics since it has various merits of nontoxicity, wide bandgap, low resistivity, and a high optical transmittance. The ZnO deposition has been intensively studied as transparent conductive films for the liquid crystal displays and thin film solar cells. Furthermore, ZnO has been used as buffer layers for gas barrier films on organic electronics devices. The ZnO deposition has been already reported by DC magnetron sputtering, chemical vapor deposition (CVD), and metal organic CVD (MOCVD). However, it was difficult to control the film thickness with a nanometer precision. In addition, these require high-temperature treatments exceeding 300 ºC, which might be problems for organic electronics and micromachines. To achieve the room temperature growth with a nanometer scale precision, we developed RT atomic layer deposition (ALD).
In this study, we report a new RT ALD with dimethyl zinc (DMZ) and an oxidation gas of plasma excited humidified Ar. We used an in-situ multiple-internal-reflection IR absorption spectroscopy (MIR-IRAS) equipped ALD system to investigate the saturation behavior in precursor adsorption and oxidization. We determined injection conditions of the precursor and oxidization gas for the RT ALD based on the IRAS experiment. The RT ALD of ZnO was performed to confirm the ZnO formation on a silicon substrate. In figure 1, we show ZnO thicknesses as a function of ALD cycle which were measured by spectroscopic ellipsometry. The growth per cycle was estimated as 0.046 nm/cycle. We evaluate its composition by using X-ray photoelectron spectroscopy and confirmed that it was fully oxidized. We assume that the deposited film was amorphous from the X-ray diffraction pattern. In addition, we discuss the reaction mechanism in this ALD with Langmuir equation fitting applied to the saturation curve plotted from the result of IR absorption spectroscopy. We depict the surface reaction scheme of the ZnO RT ALD in this paper.
Acknowledgment; This work was partly supported by JST-CREST Grant Number JPMJCR14F3, Japan. It was also partly supported by JSPS KAKENHI Grant Numbers 15H03536 and 16K17494.
Figure 1 Growth thicknesses of ZnO as a function of the ALD cycle number.

Figure 1
Analytical Modeling of Two-Phase Water Transport in a PEMFC
Authors: Rahman MD Azimur , Mojica Felipe , Chuang Po-Ya Abel 
Published: February 2020

While significant progress has been achieved in PEMFC modeling, simulating liquid water formation and transportation in a PEMFC remains a challenge. Under wet operating conditions, liquid water may condense in the channel, gas diffusion layer, or electrode, which introduces significant complexities in simulating fuel cell performance. There have been several approaches to model two-phase water transport using both macroscopic and microscopic methods. Two-phase macroscopic models are mostly based on volumetric averaged method and solve the governing equation using CFD techniques, which require intensive computational resources. In recent years, microscopic approaches based on Lattice Boltzmann Method (LBM) and pore-network approach have been applied to detailed morphological geometric domain of gas diffusion layer. While microscopic approach provide useful information, they cannot be coupled with a full fuel cell model. Therefore, constructing an effective analytical two-phase model is crucial in developing materials and design to optimizing fuel cell performance. In this work, we present an empirical-based, steady-state, 1-D, non-isothermal, and two-phase PEMFC model that includes full cell geometry and water balance. Limiting current experiments based on Caulk and Baker [1] is employed to study both dry and wet oxygen transport phenomena with wet-proofed Toray-H-060 carbon fiber paper with microporous layer. Specifically, the ratio of tortuosity and porosity under wet and dry conditions are characterized by the limiting current method and incorporated into the model. The two-phase model uses tendril length to represent the liquid water saturation and penetration in the diffusion layer. Figure 1 shows that the newly constructed two-phase model can capture the total transport resistance as a function of limiting current density in the dry, transition, and wet regions well for operating conditions at 300 kPa, 70°C, 80% and 90% relative humidity. This two-phase model also includes a two-phase electrode model, which correlates electrode relative humidity to available ECSA for fuel cell performance simulation. The details of the model and prediction results will be presented at the conference.
Referece:
1. Caulk, D.A. and Baker, D.R., 2010. Heat and water transport in hydrophobic diffusion media of PEM fuel cells. Journal of The Electrochemical Society, 157(8), pp.B1237-B1244.

Figure 1
Photoelectrochemical Properties of (K, Na)NbO3 (KNN) Thin Film
Authors: Kurohagi Masayuki , Mukouyama Yoshiharu , Ishii Satoshi , Ohsaka Hiroki , Kanno Isaku 
Published: February 2020

Photoelectrochemical (PEC) and photocatalytic (PC) processes driven by solar energy, e.g., PEC and PC water splitting, have been paid increasing attention because the processes are promising candidates to address environmental issues and energy shortages. For decades, considerable efforts have been made to find a suitable semiconductor material for the processes. Recently, sodium niobate (NaNbO3) and potassium niobate (KNbO3), which have typical ABO3 perovskite structures, attract much interst in the field of photocatalysis because NaNbO3 and KNbO3 show excellent PC activities for H2 generation (1-4). The band gap of KNbO3 is 3.1 eV, which is slightly narrower than that of NaNbO3 (3.4 eV), and thus KNbO3 shows a higher PC activity than NaNbO3 due to the narrower band gap and higher mobile charge carriers (3).
The Nb-related perovskite oxides have other interesting properties in terms of ferroelectric, piezoelectric, dielectric, and optical properties. Moreover, they exhibit photovoltaic effects due to spontaneous electric polarisation (i.e., due to their ferroelectric property). In these regards, potassium sodium niobate, (K, Na)NbO3 (KNN), has also been studied extensively. However, nothing has been studied on its PEC and PC behaviour, probably because the bulk band gap of KNN is relatively wide (4.28 eV) (5). Thus, this work aims to demonstrate the PEC behaviour of KNN thin films.
Figure 1(a) shows cyclic voltammograms (CVs) for a KNN thin film in 0.1 M (= mol/L) NaOH solution measured with and without ultraviolet-visible light irradiation. The potential (E) was scanned between -0.86 and 0.64 V vs. SHE at a rate of 0.1 Vs-1. The film was deposited onto a Pt/Ti/SiO2/Si substrate by using a radio frequency magnetron sputtering method. The KNN film exhibited a characteristic of n-type semiconductors: the oxidative photocurrent, which is likely to be due to the oxygen evolution reaction (4OH－
→ O2 + 2H2O + 4e－), started to flow at -0.5 V and increased as E increased. Figure 1b shows photo images of the KNN film before and after cycling the potential 100 times under the light irradiation. The film was hardly affected by the potential cycles, i.e., it was stable during the PEC reaction. We can thus say that the KNN is an active material for the PEC water splitting, which will be discussed in the presentation.

FIGURE CAPTION

Figure 1. (a) Photoelectrochemical behavior of a KNN thin film (the surface area: 130 mm2) measured in a 0.1 M NaOH solution. A 100W mercury lamp was employed to irradiate the KNN film electrode. (b) Photo images of the KNN film taken (left) before and (right) after cycling the potential 100 times. The potential was scanned between -0.66 and 0.64 V.

Figure 1
Elucidating the SEI Formation and Composition As a Function of Binder on Si Anodes Using in Situ Neutron Reflectometry
Authors: Browning Katie L , Doucet Mathieu , Browning James F , Sacci Robert L , Veith Gabriel M. 
Published: February 2020

This talk will highlight the use of in situ neutron reflectometry (NR) to explore the effect polymeric binders used in composite slurries have on the composition and formation of the solid electrolyte interface (SEI) on amorphous silicon (aSi) anodes. Due to the high-volume expansion, upwards of 300%, a polymeric binder is needed for added mechanical strength; however, little is known about binder interactions with Si and its effect on SEI formation. Two different binder systems, polyacrylic acid (PAA), the most commonly used binder to date, and PEFM, an electronically conductive binder, were explored using NR at various potential steps. Thin film architectures were used to provide a model electrode surface to better probe interfacial reactions. In this case vapor deposited aSi films were spin coated with low weight percent polymer binder solution to create an aSi/binder interface. NR measurements indicate changes in both the polymer layer and resulting SEI as determined by a change in material scattering length density (SLD), a measure of the composition of a layer, during the initial lithiation stage. Ex situ techniques, in this case x-ray photoelectron spectroscopy, were used in conjunction with NR measurements to confirm models of the data. Preliminary results indicate the formation of a predominantly inorganic SEI layer.
Neutrons interact with the nucleus of an atom, unlike x-rays, and as such scattering cross-section is not dependent on Z number. This allows for probing of lighter elements, especially Li, inherent to batteries. Because of their wave-like nature, neutrons follow Snell’s Law in which the beam is reflected and refracted at interfaces separating layers with different indices of refraction providing information on the thickness, roughness, and/or diffuseness of a layer and most importantly the composition described by the SLD. NR is an ideal tool to study interfaces, including buried such as those found in materials for energy storage.
Acknowledgement: This research was supported by the Vehicle Technologies Office, Hybrid Electric Systems Program, David Howell (Manager), Battery R&D, Brian Cunningham and Peter Faguy (Technology Managers), at the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. Neutron reflectometry measurements were carried out on the Liquids Reflectometer at the Spallation Neutron Source which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.