bluuebunny/crossref_metadata_2025_split huggingface dataset:
Terahertz Dielectric Response of Nonpolar a-plane GaN Films
Authors: Jang Soohwan , Jung Sunwoo , Park Jaehun , Kim Seungheun , Baik Kwang Hyeon 
Published: February 2020

The generation and the detection of the THz radiation in the frequency range of 0.1 to 10 THz have attracted much research interest, which was mainly driven by the particular applications of THz time-domain spectroscopy (TDS) in physics, chemistry, nano and life sciences. THz TDS has shown many advantages due to its non-destructive analysis feature in characterizing complex dielectric properties and understanding the carrier-dynamics in various semiconductor materials. Extensive studies have been reported on the THz dielectric and optical properties such as electro-optical effects, optical rectification, and birefringence. In addition, the ultrafast relaxation and recombination dynamics of photogenerated carriers were investigated for new materials such as carbon nanotube, graphene, and perovskites using optical pump THz-probe spectroscopy.
Recently, the terahertz (THz) quantum cascade lasers and intersubband transition devices has attracted considerable attention based on AlGaN/GaN quantum well structure for far-infrared applications. It is necessary to investigate the optical and dielectric properties of GaN and sapphire crystals in the far IR as well as THz frequency regions. In the previous report, nonpolar and semipolar GaN crystals in the hexagonal crystal system are found to show multi-phonon mode behavior in the far-infrared frequency region. In addition, the polarized IR reflectance response of sapphire is reported to exhibit the dependence on the crystal orientation. In this paper, we investigated the optical properties and dielectric response of nonpolar a-plane GaN (a-GaN) films in the terahertz (THz) frequency using polarized femto-second THz TDS. The phase separation and amplitude ratio were measured by changing the crystal orientation with respect to the polarization of the incident THz pulse. In sharp contrast with polar c-plane GaN, nonpolar a-GaN films exhibited the angle dependence of the THz absorptions at room temperature, presumably due to the birefringence in nonpolar a-GaN films. The transmitted THz signal intensity, the time delay, and the Fourier-transformed amplitude were investigated by rotating the azimuth angle of the crystal orientation. Strong THz field absorptions around 1 THz frequency were observed at the azimuth angle of 0°, 90°, and 180° for a-GaN films. We believe that the birefringence in the THz frequency region originates from the difference of the transverse-optical and the longitudinal optical phonon splitting between the optical phonon branches.
(Invited) Application of Extended-Gate Field-Effect Transistor Sensors with Molecularly Imprinted Polymer Recognition Layers for Determination of Renal Dysfunction Biomarkers
Authors: Iskierko Zofia , Sharma Piyush Sindhu , Fronc Krzysztof , D'Souza Francis , Noworyta Krzysztof R. 
Published: February 2020

In this presentation, we will discuss development of molecularly imprinted polymer (MIP) films selective towards some prospective biomarkers of renal dysfunction, namely, inosine and lipocaline-2. This artificial recognition units can easily be integrated with extended gate-field effect transistors (EG-FETs) allowing for development of selective and robust chemosensors for the target analytes [1, 2].
For the last decade, chemically-sensitive ﬁeld-effect transistors (ChemFETs) have been applied as transduction units in chemosensors. They offer numerous advantages, such as, ease of miniaturization, possibility of high-throughput sensing, high sensitivity, important detection limit, and possibility to adjust sensitivity according to specific needs. Various reports have described great variety of such devices for determination of different analytes of interest, ranging from ions, gases, small molecules, macromolecules and even whole viruses [3, 4]. Selectivity of the devised chemo- and biosensors is typically introduced by modifying gate region of the FET with suitable recognition units selective towards the analyte. In this regard, MIPs are attractive artificial recognition units offering good sensitivity and selectivity combined with robustness and resistance to harsh experimental conditions [5]. Here, we have made an attempt to combine the selectivity and robustness of MIPs with sensitivity and amplification features of EG-FET transducers to devise sensitive and selective chemosensors for selected bioanalytes.

Bibliography

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Figure 1
Investigation of DNA Detection Mechanism with AlGaN/GaN High Electron Mobility Transistor (HEMT) Biosensor in High Ionic Strength Solution
Authors: Chen Yen Wen , Hsu Chen-Pin , Sarangadharan Indu , Wang Yu-Lin 
Published: February 2020

In this research, the electrical double layer HEMT device is used to serve as the DNA biosensor. In this experiment, we try to use the DNA sequence of miRNA-126, which serve as a novel biomarkers of cardiovascular disease (CVD), to test the ability of the novel DNA sensors.
Debye length has been a haunted problem among all the field effect transistor (FET) biosensor for years. As the Debye length is extremely low in high ionic strength solutions, the traditional FET may not be direct detect the biomolecular. The novel HEMT sensors using AlGaN/GaN can performs high sensitivity and great specificity in DNA sequences testing. The sensitivity can be down to the 1fM and the specificity measurement can separate the signals between two DNA sequences with two mismatch differences. Furthermore, the mechanism of the sensor structure has also been studied. Since the structure of the device has the separation between source drain channel and gate electrode, the comparison with different electrode area and gap distance has been done as well. With repeating electrical measurement confirming, the reusability can also be seen after the 95℃ dehybridization process.
With the Gibbs free energy of the specific sequences, we can also predict the equilibrium reaction constant and the binding ratio of probe DNA with the target DNA. The comparison between the thermal dynamics with the experiment consequence has been demonstrated too.

Figure 1
(Invited) Plasmon-Enhanced Hybrid Materials for Global Health Solutions
Authors: Urban Jeffrey J 
Published: February 2020

New methods for scalable water desalination has been identified as the most impactful and necessary scientific technology for human prosperity in a 2015 report by the Institute for Globally Transformative Technologies, surpassing malaria vaccines, synthetic fertilizers, and improved TB drugs. Due to the climate change, rapidly expanding global population, and worldwide water scarcity, the demand for purification of non-traditional sources such as brackish and seawater with low environmental impacts is extensively growing. There is an increasingly urgent need for low-cost methods for water desalination that can effectively couple to, or piggyback on, renewable energy sources. In this talk I will describe our efforts in developing new materials to enhance the efficacy and utility of forward osmosis using new plasmonically-enhanced hybrid materials.
Classical membrane-based water separation and purification processes such as forward osmosis (FO) is gaining renewed attention as a potentially low-energy alternative technique to energy intensive methods such as distillation, reverse osmosis (RO), multiple effect distillation (MED), etc. Unlike RO, the industry standard for desalination, where energy intensive hydraulic/external pressure drives water flow, here an internal pressure (osmotic) drives flow. It has the characteristics of no/low pressure operation compared to standard RO processes. Consequently, membrane fouling is potentially much less severe and thinner membranes can be used. These advantages make FO extensively applied to a variety of fields to date, which could potentially relieve the stress of freshwater scarcity. As the draw solution is one of the main contributing factors to the FO process, the lack of suitable draw agent has become the obstacle jeopardizing the real application of FO in desalination process. In general, an ideal draw agent needs to provide high osmotic pressure and expel water from itself with minimal energy input. Present FO technology relies on either non-reusable draw agents or draw agents that require complicated process for regeneration.
This talk will discuss development of new classes of inorganic/organic hybrid draw agents, which exhibit high osmolalities and easy regeneration process by utilizing industrial waste heat or naturally abundant (solar, geothermal) sources. Results on the design, performance, and integration of these new draw agents will be discussed.
(Invited) Point-of-Care Diagnostics with Inkjet-Printed Microchips
Authors: Lesch Andreas , Jović Milica , Baudoz Marie , Zhu Yingdi , Tacchini Philippe , Gumy Frédéric , Girault Hubert H 
Published: February 2020

Point-of-Care (POC) diagnostics grows currently in importance. Portable devices with electrochemical detection are very attractive for the rapid and low cost identification of diseases, especially when centralized laboratories with well-equipped, automatized analytical setups are either not available or results need to be obtained rapidly on site. There is a need for portable POC devices in developing and emerging countries, but also in developed countries. Electroanalysis, often in combination with immunoassay-based detection, provides sensing platforms with high sensitivity and reproducibility without suffering from optical interferences as optical detection methods can often do.
For electroanalytical sensors, the selection and costs of the electrode materials and sensor fabrication strategies play major roles. Such considerations need to be made for the complete development chain from designing a sensor, fabricating and optimizing prototypes until reaching the industrial production scale. We found that inkjet printing, which is a digital and mask-less material deposition technique where picoliter droplets of functional inks are jetted with high precision, is the ideal tool for process development of commercial electroanalytical platforms.
Herein, we demonstrate the large-scale fabrication of electrochemical microchips with up to eight parallel 50 µL wells containing each carbon nanotube working and counter electrodes, silver/silver chloride quasi-reference electrodes and a dielectric layer to define accurately the dimensions of the electrodes. The employed carbon nanotubes show a superior electrochemical behaviour and the multi-layer inkjet printing process provides highly reproducible electrode surfaces. We shall demonstrate the application as sensing platforms for antioxidants and hormones in several biological fluids using a portable, in-house made multichannel potentiostat.

References

[1] http://lepa.epfl.ch/SENSaSION
[2] A. Lesch, F. Cortés-Salazar, M. Prudent, J. Delobel, S. Rastgar, N. Lion, J.-D. Tissot, P. Tacchini, H. H. Girault, J. Electroanal. Chem., 2014, 61-68, 717.
[3] M. Jović, Y. Zhu, A. Lesch, A. Bondarenko, F. Cortés-Salazar, F. Gumy, Hubert H. Girault, J. Electroanal. Chem., submitted.
[4] A. Lesch, F. Cortés-Salazar, V. Amstutz. P. Tacchini, H. H. Girault, Anal.
Chem., 2015, 87, 1026.
[5] A. Lesch, S. Maye, M. Jović, F. Gumy, P. Tacchini, H. H. Girault, In Biotech, Biomaterials and Biomedical TechConnect Briefs, 2016, 3, Chapter 4: Sensors, Diagnostics & Imaging, 121.
(Invited) Nanowire-Modified Electrode Enabling Low-Voltage Electroporation for Cell Inactivation
Authors: Xie Xing 
Published: February 2020

Cell inactivation is a general process that has broad applications in food, water and medical industry. Electroporation is a promising alternative to traditional cell inactivation methods (e.g., thermal, chlorine, and ultraviolet radiation), attributed to its high throughput, free chemicals usage, and outstanding efficacy to all pathogens. However, concerns of high energy consumption (>10 kJ per liter of liquid sample treated) and safety issues to generate a strong field (~107 V/m) have been the major obstacles to the large-scale implementation of electroporation for cell inactivation. To overcome these limitations, conductive one-dimensional (1D) nanostructures have been placed on electrode surfaces to generate high electric field strength near the tip of the 1D structures with low applied voltages (<20 V). Taking advantage of this phenomenon, low-voltage electroporation devices have been introduced to achieve high efficiency with low energy consumption and high throughput. For example, we have developed a new copper-oxide nanowire (CuONW)-modified 3D copper foam electrode using a facile thermal oxidation approach. An electroporation disinfection cell (EDC) equipped with two such electrodes has achieved superior water disinfection performance (>7-log removal and no detectable bacteria in the effluent). The inactivation mechanism of electroporation guarantees an exceedingly low operation voltage (1 V) and energy consumption (25 J/L) with a short contact time (7 s). Low operation voltage avoids chlorine generation, thus reduces the potential of disinfection by-products (DBPs) formation. In addition, due to irreversible electroporation damage on cell membranes, no bacteria re-growth/reactivation occurs during storage after EDC treatment.
Nylon-Graphene Composite Nonwovens As Monolithic Conductive or Capacitive Fabrics
Authors: Gao Wei 
Published: February 2020

Here we describe a nylon-graphene nonwoven (NGN) composite, prepared via dip-coating of nylon-6 nonwovens with graphen oxide (GO) in aqueous dispersions, which is later chemically reduced to introduce electrical conductivity. The correlation between the conductivity and the graphene loading is described by the percolation scaling law, with an exponent of 1.2 and a critical concentration of 0.005 wt.%, the lowest among all the reported nylon systems. Monolithic supercapacitors have been further developed on the nylon-GO nonwoven composite (NGO), via a CO2-laser patterning process. The nylon nonwoven works as the sorbent matrix, leading to the high GO loadings that ensure sufficient coating thicknesses for the subsequent laser patterning. Deep electrodes were thus easily generated by the laser beam, and our best monolithic supercapacitors exhited an areal capacitance of 10.37 mF/cm2 , much higher than the 1~3 mF/cm2 reported for typical microsupercapacitors in PVA-H2SO4 electrolyte. Moreover, our supercapacitors were able to retain a capacitance density of 5.07 mF/cm2 at a higher scan rate (1.0 V/s), probably due to the facilitated ion migration within the highly porous and interconnected nonwoven framework. This is the first report of NGN with fascinating conductive and capacitive behaviors, demonstrating great potential for applications in wearable electronics and disposable energy storage systems.
(Invited) Design Two-Dimensional Layered Materials for Rechargeable Magnesium Batteries
Authors: Yao Yan 
Published: February 2020

In the past few years, magnesium rechargeable batteries (MRBs) have attracted significant interest because of dendrite-free deposition and earth-abundant Mg resources. Despite the recent progress, the development of practical MRBs remains hindered largely due to the limited choices of Mg-intercalation electrodes. I will present our methods to overcome the large Mg2+ ion diffusion barrier to enhance the Mg diffusivity in two-dimensinoal materials. Theory, synthesis, electrochemical measurements, and kinetic analysis are combined to improve Mg diffusion behavior in MoS2, which is a poor Mg transporting material in its pristine form. I will also report a MgCl+ storage mechanism based on activated two-dimensional materials which enables high reversible capacity and excellent cycling stability.
Effect of Electrolyte Composition on Capacity Fading of Ni Rich Lithium Transition Metal Oxide Cathode for High Energy Density Lithium Ion Batteries
Authors: Kang Yoon-Sok , Choi Byungjin , Park Insun , Chung Yeonji , Koh Meiten , Ito Kimihiko , Kubo Yoshimi 
Published: February 2020

The lithium-ion battery has been widely employed in mobile applications because of its advantages, such as high energy density, insignificant self-discharge rate, and reasonable price. While it is also the most promising candidate power source for advanced automobiles, it needs further development to meet the specifications of electric vehicles1,2. For example, the driving distance of an electric vehicle on a single charge is becoming more and more important, which requires batteries with ever higher energy density. One of the main strategies to enhance the energy density is to raise the average potential and specific capacity of the cathode materials3. For this purpose, Ni rich lithium transition metal oxides have been developed for promising cathode materials4,5. Nevertheless, there are several limitations that need to be surmounted before the mass production of high energy density batteries containing Ni rich lithium transition metal oxides. In particular, significant capacity fading has been observed with lithium ion battery using Ni rich lithium transition metal oxides6,7.
In this study, we found that cathode (Ni-rich LiNi0.8Co0.1Mn0.1O2) surface modification – phase transformation from a layered structure to a cubic phase – exerted a significant influence on battery performance. Such cubic phase hindered ionic and electronic conductivity of cathode particles. The kind of the cubic phase was different by changing the composition of the electrolyte. As a result, the resistance of the cylindrical cells after 300 cycles using different electrolyte showed a large gap, especially on cathode side.
[1] B. Scrosati, J. Garche, J. Power Sources, 2010, 195, 2419
[2] M. Armand, J.-M. Tarascon, Nature, 2008, 451, 652
[3] J. B. Goodenough, Y. Kim, Chem. Mater., 2010, 22, 587
[4] W. Liu et al, Angew. Chem. Int. Ed. Engl. 2015, 54, 4440
[5] A. Manthiram et al, Adv. Energy Mater, 2016, 6, 1501010
[6] D.P. Abraham et al, Electrochem. Comm., 2002, 4, 620
[7] S. Watanabe et al, J. Power Sources, 2014, 258, 210
Infrared Optical Measurements of Thermal Breakdown in Battery Electrolytes
Authors: Porter Jason Morgan , Wheeler Jeffrey Lee 
Published: February 2020

Electrolyte thermal stability is critical for both battery safety and extending battery life. Battery fires are often the result of thermal breakdown of the liquid electrolyte leading to a flammable mixture of volatile products. Even in the absence of fire, electrolyte decomposition leads to battery swelling, harmful precipitates, reduced ion conductivities, and undesirable battery chemistry.
Current methods of determining electrolyte stability using ex-situ techniques, such as thermal gravimetric analysis or differential scanning calorimetry, can over predict thermal stability, do not address materials compatibility within batteries, and cannot identify chemical decomposition mechanisms. Infrared optical detection of thermal stability offers an in-situ approach providing: speciation, identification of chemical bonds involved in decomposition, real-time detection, and chemical kinetics.
In this work, the thermal stability of the room temperature ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]) is investigated using infrared (IR) spectroscopy. Quantitative IR absorption spectral data are measured for the heated ionic liquid. Spectra have been collected between 25°C and 100°C using a heated optical cell. Multiple samples and cell path lengths were used to determine quantitative values of the absorption coefficient. These results were compared to previous computational models of the ion pair to identify each absorption band with corresponding chemical bonds. The quantitative spectra were then used to measure the rate of thermal decomposition at elevated temperatures revealing the onset of breakdown above 75°C.
Matching Electrolyte Formulation with Cathode Chemistry
Authors: Pupek Krzysztof Z. , Dzwiniel Trevor L , Abraham Daniel P , Krumdick Gregory 
Published: February 2020

Ethylene carbonate (EC) based electrolytes, e.g. Gen2 (1.2 M LiPF6 in EC/EMC 3/7) are commonly used as a baseline electrolyte for various cathode chemistries. Is EC the best choice for all active materials? Streich [1] investigated several cathodes (NCM111, NCM622 and NCM811) using a 1M LiPF6in EC/DEM 3/7 electrolyte and reached the conclusion that there is a strong correlation between the Ni content in the active material and the amount of carbon dioxide produced in a first cycle over 4.3V. The study suggests that tailoring electrolyte formulation for the specific electrodes chemistries may be a way of improving performance of the cells. Interestingly, Dahn [2] demonstrated that it is possible to improve the performance of NCM424//graphite pouch cells by completely eliminating EC from the electrolyte formulation. While EC-reach electrolytes proved to be a good choice for some electrode chemistries they may not be the best option in all cases.
We conducted a systematic study of several cathode chemistries in full cells (CR2032) with various electrolyte formulations, with and without EC.
Figure 1 shows the effect of electrolyte formulation on cycle life of NCM523 and NCA based cells. It is clear that for cells with NCA cathode electrolytes containing EC have an adverse effect on performance whereas this effect is not observed with NCM523 cells.
Comprehensive data from cycle life and cell impedance study of several cathode materials (NCM523, NCM622, NCM811, NCA and HE5050) in various electrolyte formulations will be presented and discussed. Our study will help researchers chose electrolyte formulation for the electrode material they investigate.
[1] Daniel Streich et al., Impact of Ni content on interface reactions at NCM electrodes, GRS/GRC Ventura CA, USA, 2016, Poster 160217
[2] J. R. Dahn et al, Electrolyte System for High Voltage Li-Ion Cells, Journal of The Electrochemical Society, 163 (13) A2571-A2578 (2016)

Figure 1