bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance Evaluation of Screen-Printed Paper-Based Glucose Biofuel Cell Using MgO-Templated Porous Carbon Material for Self-Powered Diaper Sensor
Authors: Fujimura Yuki , Hoshi Yoshinao , Shitanda Isao , Tsujimura Seiya , Itagaki Masayuki 
Published: February 2020

Recently, biofuel cells have been attracted attention as compact and safe wearable power sources [1]. We have reported paper-based glucose biofuel cells in which porous carbon materials were printed by screen printing technique [2,3]. The biofuel cell can be expected to be applied to self-powered urine sugar biosensor for inspecting diabetes. In this study, we fabricated a disk-shaped paper-based biofuel cell array for power source of a self-powered diaper sensor. In this paper, we discuss a performance of a single biofuel cell.
The paper-based biofuel cell anode and cathode were fabricated by screen-printing. The MgO-templated porous carbon ink was printed for bioanode and biocathode. Tetrathiafulvalene (TTF) and glucose oxidase (GOD) was modified on the bioanode surface. The biocathode was prepared by modifying bilirubin oxidase (BOD). The biofuel cell was prepared by stacking the non-printed side of paper substrate of bioanode and biocathode by using water repellent double-sided tape. During the measurements, the edges of the paper substrate of bioanode, the biocathode and the cell were immersed in the 1 M phosphate buffer solution containing glucose.
Figure1 shows cyclic voltammograms of the bioanode in a phosphate buffer containing 100 mM glucose at 37 ℃. Compared to the background current measured in 0 mM glucose solution, a catalytic current wave related to glucose oxidation was clearly observed in the presence of glucose, and the maximum current density was 7.4 mA cm-2 at 0.5 V. Figure 2 shows the relation between power density and operating cell voltage with different concentration of glucose at 37 ℃. It was confirmed that the output power density increased along with increase of the glucose concentration. Finally, a disk-type biofuel cell array was prepared and output evaluation was carried out.
Acknowledgement
This work was supported by JST-ASTEP Grant Number AS272S004a.
References
(1) L. Zhang et al., Biosens. Bioelectron. 35 (2012)155-159.
(2) I. Shitanda et al., Chem. Commun. 49 (2013) 11110-11112.
(3) I. Shitanda et al., J. Power Sources, 360 (2017) 516-519.

Figure 1
(Invited) Wearable Printed Pressure Sensors with Ferroelectric Polymer for Healthcare Applications
Authors: Sekine Tomohito , Takeda Yasunori , Matsui Hiroyuki , Kumaki Daisuke , Dos Santos Fabrice Domingues , Atsushi Miyabo , Tokito Shizuo 
Published: February 2020

<Introduction>
Flexible printed organic electronics have various advantages over conventional inorganic electronics. These organic devices such as sensors and actuators can be fabricated on a plastic thin-film substrate with low-temperature printing processes[1,2]. Especially, physical sensors based on a ferroelectric polymer have a great potential in the development of wearable and disposable health-care devices such as pressure sensors. As the ferroelectric polymer for the sensors, poly(vinylidene difluoride trifluoroethylene) [P(VDF–TrFE)] (Piezotech, 62-010, VDF:TrFE molar ratio of 75:25) is the most promising material because of high ferroelectricity and piezoelectricity[3]). Moreover, the P(VDF–TrFE) is compatible with printing processes because of its solubility in several organic solvents[4,5].
<Results and Discussions>
A representative printed physical sensor based on P(VDF–TrFE) was fabricated on a flexible plastic film substrate by screen printing method. PEDOT:PSS (Heraeus, Clevios SV 4 Stab) was used for the top and bottom electrodes. Thicknesses of the P(VDF–TrFE) layer and the electrodes were 2 µm and 1 µm, respectively. The P(VDF–TrFE) layer could generate the voltage of 50 mV by applied pressure of 50 kPa[5]. The generated voltage clearly depended on the thickness of P(VDF–TrFE) layer. Our printed sensor exhibited high sensitivity in the low pressure region, which is indicating the potential application to wearable sensors which monitoring health condition of human. In order to monitor the health condition of a volunteer, the sensor was attached to the skin near the neck using a skin-compatible adhesive patch. We have succeeded in the detection of the pulse rate with 55 pulse per minute. These results indicate that our P(VDF–TrFE) based sensor is significantly promising for wearable health-care applications.
The detection of the pulse rate from volunteer was authorized by the Ethics Committee of Yamagata University (authorization code: 29-2).
<Acknowledgement>
This study was partially supported by the Japan Science and Technology Agency (JST). T. S. would like to thank all member of Research Center for Organic Electronics in Yamagata University, Piezotech and Arkema corporation.
<References>
[1] K. Fukuda et al., Sci. Rep., 3, 2048 (2013).
[2] S. Conti et al., Adv. Mater. Technol., 2, 1600212 (2017).
[3] D. Thuau et al., J. Mater. Chem. C, 5, 9963 (2017).
[4] G. Knotts et al., Appl. Phys, Lett., 104, 233301 (2014).
[5] T. Sekine et al., Sci. Rep., 8, 4442 (2018).
Fabrication of Flexible Metal Oxide Thin Film Transistor By Indigenously Developed Spray Pyrolysis Unit
Authors: Omprakash S S , Naveen Kumar S K 
Published: February 2020

The deposition of polyvinyl alcohol (PVA) dielectrics and semiconductor Zinc oxide (ZnO) thin film is developed by custom designed spray pyrolysis unit. The solutions for spray are prepared by PVA and zinc acetate dehydrated as precursor materials. These solutions are deposited on a substrate such as Aluminium coated polyimide and polyimide film The Aluminium is used as Source and drain electrodes. PVA and ZnO deposited on these electrodes is act as the gate oxide and channel layers for thin film transistor (TFT). Gate electrodes are deposited by thermal evaporation of Al using shadow mask method. Finally, top gated TFT is fabricated.
Results: The morphology of the films was characterized by FESEM which confirmed that the film was uniform with no cracks. The XRD results are confirm the amorphous nature of ZnO thin film. The PVA coatings are also examined for electrical properties like C-V. The thickness and roughness of films were measured using optical Profilometer. The optical studies of the film are studied and the band gap is calculated using Tauc plot. A study has been performed on ZnO for its electrical characteristics such as mobility and resistivity. The TFT characteristics like input and output has been carried out.

Keywords: TTF, Spray pyrolysis, PVA, ZnO,

Figure 1
Quantum Chemistry As a Tool for Materials Development
Authors: Correa Andrea 
Published: February 2020

In the past, new materials have been developed by empirically correlating their chemical composition, and the manufacturing processes used to form them, with their properties.
The rapid advancements in quantum theory, computer science, and computational power brought about tremendous developments in materials research. Nowadays quantum chemistry, or more generally computational chemistry, can be used as a tool for developments of new materials through a synergic, computational and experimental, work.
In this presentation we will give an overview of how a combination of efficient quantum mechanic calculations and experimental data can lead to new materials development through catalyst rational design. In the first part, we will focus our attention on polymeric materials by Ziegler-Natta catalysis, and production of new materials through organometallic metathesis. Then, application quantum chemistry to the study of solar cell systems will be discussed.
Challenging the Limits of Nanoscale Simulations: Modeling Joule Effect and Piezoresistivity in Carbon Nanotubes Enforced Polymers
Authors: Donati Greta , Milano Giuseppe 
Published: February 2020

The unique electric properties of carbon nanotubes (CNT)1, have opened new scientific and technological fields2 based on the investigation and optimization of CNT filled polymers3. CNTs, when added to polymer matrices (such as epoxy, bitumen, concrete) make them conductive once they overcome a specific (so-called percolative) concentration4. When this percolative threshold is reached, a CNT electric circuit is formed and the composite materials become conductors. Based on such peculiar behavior, smart materials able to monitor their own conditions could be realized and employed for several applications ranging from automotive and aeronautics to civil engineering infrastructures.
The main goal of this work is to understand, through a theoretical-computational approach, the electric behavior of CNT based composites5 and help in improving their performances. In particular, the Joule effect, i.e. the heat dissipation of the conductive CNTs is simulated. The CNTs Joule effect can be employed to build smart materials able to have specific properties (i.e. self-deicing under certain temperatures) or to repair their own cracks (self-healing). The piezoresistivity, i.e. the change in the electric resistance of the CNTs due to an applied strain or stress, is also investigated. This feature allows these composites to be sensitive to an external stress or damage (self-sensing), in this way an immediate and efficient repair can be performed.
A computational protocol to understand the behavior, the sensitivity and the limits of such materials at the nanoscale is proposed. This will improve the materials performances and efficiency on larger scales. For the first time, a computational modeling strategy along with preliminary results is built and presented to simulate at the nanoscale the Joule effect and the piezoresistivity of CNTs filled polymers. Obtaining a widely applicable strategy to model electric properties of CNTs and characteristic behavior trends of such materials is the final goal of this project.
[1] Iijima, Nature, 1991, 354, 56-58.
[2] W. Nan, Y. Shen, J. Ma, Annu.Rev.Mater.Res., 2010, 40, 131-151.
[3] M. Ajayan, O. Stephan, C. Colliex, D. Trauth, Science, 1994, 265, 1212-1214.
[4] M. Mutiso, K. I. Winey, Prog. Polym. Sci., 2015, 40, 63.84.
[5] Zhao, M. Byshkin, Y. Cong, T. Kawakatsu, L. Guadagno, A. De Nicola, N. Yu, G. Milano, B. Dong, Nanoscale, 2016, 8, 15538-15552.
Effect of Molding Condition on Mechanical Properties in Injection and Compression Hybrid Molding
Authors: Nakai Asami , Funahashi Masahiro 
Published: February 2020

The advantage for discontinuous fiber reinforced thermoplastic composite is to form a complicated shape in a short time. On the other hand, the continuous fiber reinforced plastic (c-FRTP) has high mechanical properties, but its process ability is limited and it is difficult to produce complicated shapes such as ribs. Therefore, the hybrid molding method attracts attention.
The hybrid molding method used in this study is a molding method combined the compression molding with continuous fiber and the injection molding with discontinuous fiber. Hybrid molding is a method of injecting and joining discontinuous fibers to a continuous fiber part. The part of requiring strength is formed by compression molding of intermediate material with continuous fiber, and the complicated shape part is made by injection molding of discontinuous fiber.
However, there is a problem with the strength of the joint part between the intermediate material part molded by compression molding and the part molded by injection molding. Joining characteristics are affected by preheating conditions of c-FRTP, molding conditions such as temperature, pressure and speed of injection resin. Therefore, it was aimed to clarify the effects of the preheating condition for the intermediate material and the temperature of the injection resin on the mechanical properties of the molding and injection resin joint.
In this research, a hybrid molding machine of a press machine and an injection machine was used. A heating test was conducted by using preheating devices, and the temperature distribution and the difference in temperature rise were investigated. In addition, the influence of the difference in the preheating condition of the intermediate material on the strength was examined by evaluation of mechanical properties, surface and cross sectional observations. From this study, middle infrared was found out to be the most suitable preheating device for hybrid molding, from its advantages that could preheat in a short time and improves mechanical property.
(Invited) Organic and Inorganic Materials for Efficient Pb and Pb-Free Perovskite Solar Cells
Authors: Wakamiya Atsushi 
Published: February 2020

Perovskite solar cells have attracted much attention as cost-effective next generation printable photovoltaics. In a relatively short period, power conversion efficiencies in such cells have been substantially increased, mainly due to improvements of the fabrication protocols for the perovskite layer as well as the development of new materials for buffer layers.
Our approaches toward efficient lead and lead-free perovskite solar cells are as follows.
1) Development of organic semiconductors as efficient charge-collection layer: We design and synthesis of novel p-conjugated materials in terms of control of the energy level of frontier orbitals and molecular aggregation.
2) Development of highly purified perovskite precursor materials: We synthesis of a series of complexes of lead halides or tin halides as purified precursor for perovskite materials.
3) Development of fabrication methods for perovskite layer by solution process: We focus on the intermediates formed during the solution process and develop efficient fabrication methods based on the mechanism.
In this talk, we introduce our recent progress on tin halide perovskite solar cells as well as lead halide perovskites.
Study of Active Center Structures for Fe/N/C Type Oxygen Reduction Catalyst Using Semi-Empirical Molecular Orbital Calculations
Authors: Shiroishi Hidenobu , Ono Ryoma 
Published: February 2020

Polymer electrolyte fuel cells (PEFCs) are one of the most important devices in realizing hydrogen society. Platinum, which is used as the catalyst of PEFCs, is expensive and less abundant. Thus, the development of a non-platinum oxygen reduction catalyst is required for the wide-spread use of PEFCs. Fe/N/C non-platinum oxygen reduction catalysts are promising platinum alternative catalyst candidates. We have reported new metal/nitrogen/carbon-electrocatalysts synthesized by the pyrolysis of precursors consisting of Ketjenblack®, a Zn complex with 4,4’-bipyridine, 1,10-phenanthroline (phen), and iron(II) chloride1)．The density of active sites on the catalysts need to be increased for the improvement of for oxygen reduction reaction (ORR). Although we obtained that pyridine type nitrogen is related to the ORR activity, the chemical structure of the active center is still unknown. The conclusion does not match whether Fe atoms function as activity centers2-3．In this study, the structures of active center for Fe/N/C ORR catalysts were studied using semi-empirical molecular orbital calculations．
Assuming that four electrons were injected into the compound, the distance between an O2 molecule and atoms was stepwise shortened with the parameters4 using MOPAC 20165. The result of the calculation was visualized by Jmol6. We used model compounds modeling a part of the edge of a graphite layer (Fig. 1(a)).
Fig. 1(b) shows the dependence of ΔH on the distance between O and target atoms during shortening distance. The activation energies of route (i) was the smallest of the four routes. The cleavage of O-O bond occurred at routes (i) and (iv). The supply of further proton via H3O+ is necessary in the route (ii) and (iii).
References and Notes

Shimbori, H. Shiroishi, R. Ono, S. Kosaka, M. Saito, T. Yoshida, H. Katagiri, K. Miyazawa, Y. Tanaka, Mat. Sci. Eng. B, 228, 190 (2018).

Lefèvre, J.P. Dodelet, P. Bertrand, J. Phys. Chem. B
, 106, 8705 (2002).

Guo, R. Shibuya, C. Akiba, S. Saji, T. Kondo, J. Nakamura, Science, 351, 361 (2016).

Typical calculation parameters of MOPAC used in the simulations: PM6-DH2 EF PRECISE PULAY CAMP ITRY=9999 SHIFT=50 SYMMETRY STEP=-0.025 POINT=74 NOINTER GRAPHF EPS=78.5 NSPA=200 (UHF) CHARGE=(2 to -2).

MOPAC2016, James J. P. Stewart, Stewart Computational Chemistry, Colorado Springs, CO, USA, HTTP://OpenMOPAC.net (2016).

Jmol: an open-source Java viewer for chemical structures in 3D. http://www.jmol.org/

Figure 1
Adsorption and Desorption Properties of CeO2 Nanoparticles for Concentrating Dilute CO2
Authors: Kanahara Keita , Matsushima Yuta 
Published: February 2020

A recent concern about an energy issue has encouraged investigation on photocatalytic [1] or electrochemical [2] conversion of CO2 to fuels such as methane and methanol. For the realization of the conversion of CO2 to fuels, a technique concentrating dilute CO2 in the atmosphere also becomes important. A rare-earth oxide of CeO2 is an excellent adsorbant against CO2 [3]. The advantage is that CeO2 adsorbs CO2 near room temperature and releases it until 300 °C. The mass of the CO2 adsorbed to 1 g of CeO2 reaches 0.04 g at most, although the adsorption and desorption properties are dependent on the natures of particles. The crucial factors have not been revealed yet. In this work, we prepared several CeO2 nanoparticles with different synthetic routes and characterized their properties with respect to the unit cell dimensions, morphologies, and specific surface areas. The CeO2 nanoparticles were prepared by (1) thermal decomposition of Ce2(CO3)2·8H2O or CeCO3OH, and (2) precipitation by raising the pH of Ce(NH4)2(NO3)6 aq with NH3 or CO(NH2)2. Some samples were heat-treated at 300 °C to improve the crystallinity and the effects of the heat treatment were examined.
The adsorption and desorption properties were characterized by thermogravimetric (TG) analysis (Rigaku Thermo plus EVO), in which a powder sample was pretreated in TG in dry CO2 at 250 °C to remove the adsorbed CO2 and H2O and then kept at 25 °C in CO2 for adsorption equilibrium. The mass of the adsorbed CO2 was calculated from the weight change between 25 and 250 °C.
XRD indicated the formation of fluorite type CeO2 regardless of the preparation routes. TEM observation revealed that the prepared samples were composed of nano-sized particles less than 10 nm. The TEM observation exhibited well crystallized nanoparticles of CeO2 with clear lattice fringes in the images. The broadened XRD peaks were attributed to the smallness of the grain size. The CeO2 particles prepared via thermal decomposition of Ce2(CO3)·8H2O or CeCO3OH showed better performance on CO2 adsorption. Quite interestingly, there was no distinct correlation between the specific surface areas evaluated by N2 adsorption and the CO2 adsorption. Rather, the nanoparticles which had a specific crystallite size around 5~6 nm appeared to be advantageous on the CO2 adsorption as shown in Fig. 1. Fig. 1 shows the adsorbed mass of CO2 to 1 g of the CeO2 powders prepared via the different synthetic routes. An increasing tendency can be seen in the adsorbed mass until 6 nm when the data was plotted against the crystallite size.
[1] H. Rao et al., Nature 548 (2017) 74.
[2] S. Kaneco et al., Ind. Eng. Chem. Res. 41 (2002) 5165.
[3] C. Li et al., J. Chem. Soc. Faraday Trans 1 (1989) 3901.

Figure 1
(Keynote) Nanomaterials and Interfaces for Efficient Solar Energy Conversion
Authors: Yang Shihe 
Published: February 2020

Nanostructured materials and interfaces are critical to the functioning of solar energy conversion devices. For photovoltaics, hybrid organic/inorganic halide perovskite solar cells have emerged as among the most competitive photovoltaic technologies of the future thanks to their superb and rapidly improving power conversion efficiencies (PCEs). For realistic deployment of the perovskite photovoltaic technology in large scale, however, device stability has become more and more important issue of the day. I will update our recent efforts in the material and interface innovations to develop high-efficiency and high-stability perovskite solar cells: (1) the relationship between device stability and ion movement of the perovskite layer; 2) the use of NiO and carbon nanostructures for efficient hole extraction and enhanced device stability; and 3) the development of perovskite and interface engineering techniques for improving both efficiency and stability. Implications of these results on the future development of perovskite solar cells will be discussed.
For electrocatalysts needed for generating solar fuels, I will focused on two-dimensional (2D) materials. In particular, molybdenum sulfide (MoS2) is an attractive noble-metal-free electrocatalyst for the hydrogen evolution reaction (HER). We have recently demonstrated significantly enhanced HER kinetics by controllably fabricating a stepped MoS2 surface structure. Vertical arrays of MoS2 sheets terminated with such a stepped surface structure have proved to be an outstanding HER electrocatalyst with overpotential of 104 mV at 10 mA/cm2, exchange current density of 0.2 mA/cm2 and high stability. Experimental and theoretical results indicate that the enhanced electrocatalytic activity of the vertical MoS2 arrays is associated with the unique vertically terminated, highly exposed, stepped surface structure with a nearly thermoneutral H-adsorption energy.
The HER electrocatalyst we engineered above, albeit based on the earth-abundant 2D MoS2, is only active in acidic media, and the HER reaction kinetically retarded in alkaline media. Thus, improving the sluggish kinetics for HER in alkaline media is crucial for advancing the performance of water-alkali electrolyzers. Toward this end, we have demonstrated a dramatic enhancement of HER kinetics in base by judiciously hybridizing vertical MoS2 sheets with another earth-abundant material, layered double hydroxide (LDH). The resultant MoS2/NiCo-LDH hybrid exhibits an extremely low HER overpotential of 78 mV at 10 mA/cm2 and a low Tafel slope of 76.6 mV/dec in 1 M KOH solution. At the current density of 20 mA/cm2 or even higher, the MoS2/NiCo-LDH composite can operate without degradation for 48 hr. This work not only brought forth a cost-effective and robust electrocatalyst, but more generally opened up new vistas for developing high-performance electrocatalysts in unfavorable media recalcitrant to conventional catalyst design.