bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Diffusion Barrier of Vapor Phase Infiltrated Pen with Room Temperature ALD
Authors: Yoshida Kazuki , Saito Kentaro , Miura Masanori , Kanomata Kensaku , Hirose Fumihiko 
Published: May 2020

Metal oxides like aluminum oxide (Al2O3) and silicon oxide (SiO2) are well known as gas barrier materials to moisture. The gas barrier films are used in various applications like food packaging, pharmaceuticals, chemicals, and organic electronics. Especially in the field of organic electronics, the high gas barrier performance is essential to avoid organic semiconducting material degradation from moisture. Because of the most attractive point in these devices is their possibility that of flexible device fabrication, we must use a flexible polymer film substrate. The polymer film substrate is thermally fragile, and it includes voids in polymer chains. From this, we have to deposit the gas barrier film at low temperature and uniformly coat the voids. To overcome these problems, we developed the room-temperature atomic layer deposition (RT-ALD) technologies. In this study, we examine gas barrier coatings with a combination of vapor phase infiltration (VPI) for higher barrier performances. The VPI produces a polymer-inorganic hybrid layer by infiltrating inorganic materials into polymer substrates in the subsurface region. It is possible to fill in the voids in polymer substrates.
For VPI, we used tris(dimethylamino)silane (TDMAS) as the infiltration gas and plasma excited humidified Ar as oxidation gas. The infiltration process was operated at room temperature of 25 °C. The PEN film was infiltrated by being kept in a vacuum chamber with a TDMAS pressure of 200 Pa for 6 hours. After infiltration, the PEN films were exposed to plasma excited humidified Ar to oxidize surface absorbant. In the RT ALD, we used trimethylaluminum (TMA) and dimethylzinc (DMZ) as the precursor and oxidation gas was the same as VPI. We fabricated the gas barrier films with a ZnO single layer and a laminated Al2O3/ ZnO.
In figure 1, we show Si 2p narrow scan spectra of TDMAS infiltrated PEN by X-ray photoelectron spectroscopy. The Si 2p peak existed after 90 min Ar bombardment etching. It indicates the TDMAS molecules penetrated in the PEN film. We also confirmed that its surface became smooth and its morphology was changed by using AFM. The surface modification by VPI was evaluated with a water contact angle meter. In this paper, we will release the WVTR data and discuss its performance compared with the pristine PEN.

Figure 1
Elucidating Aluminum-Ion Intercalation and Its Effects on the Local Crystalline Framework Using Solid-State NMR Spectroscopy
Authors: Jadhav Ankur L. , Hawkins Brendan E. , Xu Jeffrey H. , Messinger Robert J. 
Published: May 2020

Rechargeable multivalent-ion batteries are safe and low-cost alternatives to traditional lithium-ion batteries. However, higher Coulombic charge density of the multivalent ions results into sluggish diffusion of their respective cations within crystalline transition metal compounds. The Chevrel phases Mo6X8, where X is a chalcogen atom (e.g., S or Se) are among the few materials known to reversibly and electrochemically intercalate both divalent (e.g. Mg2+, Zn 2+, etc.) and trivalent (Al3+) ions. Thus, understanding the ion intercalation and charge transfer mechanisms within these unique compounds may provide insights into the molecular-level design of new intercalation electrodes for rechargeable multivalent ion batteries. Here, we use multi-nuclear solid-state magic-angle-spinning (MAS) NMR spectroscopy to reveal the ion intercalation and charge transfer mechanisms of zinc and aluminum intercalation in Chevrel electrodes Mo6S8 and Mo6Se8.

Ex situ single pulse solid-state 27Al MAS NMR measurements were performed on the thio-chevrel electrodes at different states-of-charge to observe changes in the environments and to quantify the local populations of aluminum ions within the host crystal structure, revealing both intercalated ions and additional aluminum species associated with surface layers and/or decomposition products. Al-Mo6Se8 batteries were made for the first time and their electrochemical properties were compared to the thio-chevrel Mo6S8. Ex situ
77Se and 95Mo measurements on the seleno-chevrel Mo6Se8 at charged and discharged states revealed that the electrons are transferred to the anionic chalcogen framework the electron charge transfer mechanism and its effects on the local crystalline framework environments upon aluminum ion intercalation. These results were then generalized for zinc intercalation into chevrel phase electrodes.
Overall, the solid-state NMR measurements combined with the electrochemical measurements yield molecular-level insights into the coupled aluminum ion intercalation and electron charge transfer processes that occur in a model crystalline transition metal electrode. Unique reversible anionic redox reactions were observed for multivalent ion intercalation into chevrel, which is very different that typically observed for lithium-ion intercalation into transition metal oxides, where the electrons are stored into the d-orbitals of the transition metal. The results suggest materials design principles aimed at designing multivalent-ion intercalation electrodes with improved electrochemical properties.

Figure 1
Protocols to Observe Changes in the Lower Critical Solution Temperature Induced By an Applied Potential
Authors: LaFreniere Joelle , Ren Tianyu , Roberge Emma , Balog Eva Rose M , Seitz William Rudolf , Halpern Jeffrey M 
Published: May 2020

Dynamic light scattering, or DLS, is commonly used to determine the lower critical transition temperature (LCST) of a temperature induced stimuli-responsive polymer. By applying a temperature sweep, the coacervation or agglomeration of stimuli-responsive polymers can be observed. For materials, such as Poly(N-isopropylacrylamide), or pNIPAM, which have a reverse LCST, the polymers are soluble at lower temperatures and condense or precipitate out of solution at higher temperatures. The transition temperature is the transition between this soluble and condensed state.
Our lab has developed a protocol to look at changes in the LCST behavior in the presence of an applied potential. By lining the DLS cuvette with a conductive tape, we can apply the potential across the 1 cm light path. After a certain voltage threshold, changes in the observed LCST behavior is found with pNIPAM. To the best of our knowledge, this result has never been recorded. Typically, the LCST of pNIPAM is not adjustable, but using this technique, we can observe the effect with an applied potential. We share this protocol for other groups to use to investigate the effect of applied potential on the coacervation of stimuli-responsive polymers. We intend to report details of our protocol and initially observed results of the observed behavior in the presence of an applied potential.

Acknowledgements: The authors would like to acknowledge the financial support from NIH (P20 GM113131), NSF (CBET 1638896), the Collaborative Research Excellence Initiative Pilot Research Program at the University of New Hampshire, and the Hamel Center of Undergraduate Research at the University of New Hampshire. The authors also would like to acknowledge the assistance of Dr. Balog’s laboratory and Dr. Halpern’s laboratory.
IR Study on Room Temperature Atomic Layer Deposition of Aluminum Nitride Using Plasma Excited Ammonia
Authors: Saito Kentaro , Yoshida Kazuki , Miura Masanori , Kanomata Kensaku , Ahmmad Bashir , Kubota Shigeru , Hirose Fumihiko 
Published: May 2020

Aluminum nitride (AlN) has been attracting much attention since it has a wide direct transition band gap of 6.3 eV and it is applicable for UV-LEDs. The AlN films have been deposited by chemical vapor deposition (CVD) and atomic layer deposition (ALD). These conventional processes were performed at a temperature of 300 °C and higher. To apply the AlN coating on flexible films, the low temperature deposition process has been demanded. To demonstrate the AlN deposition at RT, an RT-ALD of AlN using trimethylaluminum (TMA) as an Al precursor and plasma-excited ammonia are studied based on study on multiple internal reflection infrared spectroscopy (MIR-IRAS).
An n-type Si substrate was used as a prism for MIR-IRAS. The size of prism was 10×45 mm2 and its resistivity was 1000 Ωcm. 45° bevels on each of the short edges were formed. The prism was set in a reaction chamber for the ALD. If the IR spectra before and after the processes are defined as Ir and I0, respectively, we can calculate the absorbance (Abs) from the equation, Abs = log10(Ir/I0). TMA was used as the Al precursor. In the nitridation step, ammonia and argon was mixed with a volume ratio of 7:3, followed by being excited through a quartz tube with an RF power of 250 W and a frequency of 13.56 MHz. The flow rate of the mixed gas was 10 sccm. Ammonia molecules in the mixture were dissociated to NH radicals and some fragments. Plasma excited ammonia was provided in the chamber.
We observed the surface reaction to confirm TMA adsorption and examine if the plasma-excited ammonia generated nitride on the TMA adsorbed surfaces. Fig. 1 shows IR spectra were obtained from a TMA adsorbed surface with exposures from 1000 to 400000 L at RT. Peaks at 2933, 2894, and 2829 cm-1 correspond to C-H vibrations in TMA. The positive peak indicates that the TMA was adsorbed on the surface at RT. Fig. 2 shows IR spectra measured from plasma excited ammonia treated TMA saturated surface. Negative peaks at 2933, 2894, and 2829 cm-1 suggests that the nitride was generated there at RT. We also confirmed the presence of AlN on the prism by an Al 2p peak at 73.3 eV and a N 1s peak at 398.1 eV by X-ray photoelectron spectroscopy. These suggests that it is possible to deposit AlN at RT.

Figure 1
Transparent and Stretchable Supercapacitors Based on PEDOT:PSS/Nano-Metal Oxide Composite Electrodes
Authors: Feng Wei , Chen Han-Yi , Huang Jin-Hua 
Published: May 2020

Owing to advances in technology, people focus more on electronic devices that are both aesthetic and functional. Therefore, stretchable and transparent electronic devices have been widely used in wearable devices, transparent displays, and other fields. In the meanwhile, stretchable and transparent energy storage devices are developed to support those electronic devices. Therefore, this study aims to fabricate stretchable and transparent supercapacitors with high electrochemical performance.
Conductive polymer poly(3,4-ethylene dioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS) is a promising candidate for the transparent electrode of supercapacitors as it is highly transparent, stretchable and provides well electrochemical performance. However, the PEDOT:PSS electrode suffers from low capacitance. This study focus on combining PEDOT:PSS with nano-metal oxides as hybrid electrodes. All-solid-state asymmetric supercapacitors assembled with those hybrid electrodes and gel electrolyte are highly transparent, stretchable and possess superior electrochemical performance. This research demonstrates the great potential of highly stretchable and robust all-solid-state asymmetric supercapacitor based on PEDOT:PSS/nano-metal oxide composite electrodes.
Free-Standing Poly (Acrylic) Acid / Potassium Hydroxide Based Polymer Electrolyte Membrane As Electrolyte for Printed Zinc/Silver Oxide Batteries
Authors: Singh Gaganjot , Katiyar Monica 
Published: May 2020

Printable batteries have attracted great attention as an emerging power source for wearable electronics such as RFID tags, implantable medical devices etc. The need for environmentally friendly batteries with high energy density has led to the development of partially printed primary zinc-silver oxide batteries. It has been reported that printed Zn/Ag2O systems have low cost, lightweight and easy processing methods. A free-standing polymer membrane (FSM) made up of poly(acrylic) acid, poly(ethylene)oxide and potassium hydroxide has not been systematically studied for its application as an electrolyte in printed batteries. In this work, we have prepared and characterized FSM for its compatibility to be used as an electrolyte in a Zn/Ag2O systems by employing electrochemical, microscopic and spectroscopic techniques. Cyclic voltammetry is used to understand the electrochemical processes going on the electrode, charge-discharge curves are reported to present the specific capacity of the battery. For printed electrodes, ionic conductivity is of the order of 10-3 siemens.cm-1 transference number (Zn+), for Zn|| FSM||Zn (Printed zinc (Zn)) cell structure is 0.247.
Further, a comparative study of FSM behavior with printed zinc and the zinc metal foil electrodes is done with an intention to understand the electrochemical behaviour of zinc electrodes in Zn/Ag2O all-solid-state battery device. Specific capacities of 3.604 and 2.495 mAh.cm-2are achieved for batteries having zinc printed and metal foil electrodes respectively. Though printed electrodes demonstrated better specific capacity, its repeatability remains an issue. Further work is being done to address the issue of electrode recyclability and performance repeatability.
Vitamin-Based Organic Electrolytes for Redox Flow Batteries
Authors: Shi Raymond Rong Sheng , Lauw Sherman Jun Liang , Foo Nicolette Angelique Bao Yun , Webster Richard David 
Published: May 2020

With the current drive towards environmental sustainability, electrochemical energy storage system (EES) such as redox flow batteries (RFB) are thought to be a promising solution as they can play an important role in balancing energy generation and consumption to ensure power network stability and reliability. [1,2] Organic compounds possess tremendous potential for energy storage as they are structural diverse and synthetically tunable. In addition, organic compounds can be cost-effective and environmentally benign due to their abundancy in nature. However, many organic species experience stability issue in their charged form. [3,4] The present study reports an all-organic vitamin-based molecular system based on a non-aqueous, mixed-reactant electrolyte containing modified forms of the naturally occurring vitamin K1 and vitamin E as anolyte and catholyte, respectively. [5,6] In the presence of malonic ester (a relatively weak organic acid), the redox transformations of the organic species were proven chemically stable and reversible under exhaustive electrolysis conditions, as confirmed by UV-vis spectroscopy. [7] The pairing of both half-cells provides a desirable experimental cell voltage of 1.27 V. The proposed system also demonstrates good thermal and ambient stability via series of experiments. The overall findings presented demonstrate the practical significance of the vitamin-based organic electrolytes in the all-organic RFB technologies.

References

1. S. H. Shin, S. H. Yun and S. H. Moon, RSC Adv, (3) 2013, 9095-9116.
2. X. Luo, J. Wang, M. Dooner and J. Clarke, Appl. Energy, (137) 2015, 511-536.
3. X. Wei, X. L.; Xu, W.; Huang, J. H.; Zhang, L; Walter, E.; Lawrence, C.; Vijayakumar, M.; Henderson, W. A.; Liu, T. B.; Cosimbescu, L.; Li, B.; Sprenkle, V; Wang, W. Chem. Int. Ed.
2015, 54, 8684 –8687.
4. X. Wei, X. L.; Pan, W. X.; Duan, W. T.; Hollas, A.; Yang, Z.; Li, B.; Nie, Z. M.; Liu, J.; Reed, D.; Wang, W.; Sprenkle, V. L. ACS Energy Lett. 2017, 2 (9), 2187-2204.
5. Y. L. Hui, E. L. K. Chng, Y. L. C. Chng, H. L. Poh and R. D. Webster, J. Am. Chem. Soc, (131) 2009, 1523-1534.
6. H. M. Peng, B. F. Choules, W. W. Yao, Z. Zhang, R. D. Webster and P. M. Gill, J. Phys. Chem B, (112) 2008, 10367–10374.
7. R. R. S. Shi, M. E. Tessensohn, S. J. L. Lauw, N. A. B. Y. Foo and R. D. Webster, Chem. Commun, (55) 2019, 2277.
Nitric Oxide Synthase-Based NO-Releasing Films for Improved Biocompatibility of Blood-Contacting Medical Devices
Authors: Maher Shaimaa , Kalil Haitham , Bayachou Mekki 
Published: May 2020

Blood-contacting medical devices, such as vascular grafts, stents, heart valves, and catheters, are often used to treat cardiovascular diseases. These implantable medical devices, even if labeled as biocompatible, can cause serious complications in patients. Thrombus formation and infection are the main causes of failure of these devices. In contrast to the healthy endothelium, which actively resists thrombosis, artificial surfaces promote clotting through a complex series of interconnected processes that include protein adsorption, adhesion of platelet, leukocytes and red blood cells, ending with thrombosis.
Nitric oxide is an important intercellular and intracellular signal molecule that regulates the cardiovascular, nervous, and immune systems. It is generated from L-arginine by a family of enzymes, called nitric oxide synthases. Under physiological conditions, a constitutive Ca2+-dependent NOS in endothelial cells (eNOS) is responsible for the continuous release of NO. In addition to its role in vasodilation and regulation of vascular tone, continuous release of NO by the endothelium has also been shown to counteract the adhesion of platelets to the inner walls of blood vessels. From this standpoint, NO is a natural antithrombotic agent in blood vessels. In this regard, NO-releasing films as coatings on blood-contacting devices have shown the potential to be effective in preventing platelet adhesion, activation, and aggregation, therefore reducing the risk of thrombus formation on the treated surfaces.
In this project, we use layer-by-layer thin film building strategy to form layers of polyethyleneimine (PEI) and recombinant NOS as NO-releasing coatings. Charge-based Layer-by-layer electrostatic adsorption allows for assembly of multi-component protein/PEI films. When surfaces coated with PEI/NOS multilayered films are exposed to substrate arginine, a source of reducing equivalents, and other ingredients of the NOS reaction, nitric oxide is formed and released. In this work, we characterize the PEI/NOS thin films in terms of structure of NOS within the films as well as the amount of active NOS. Fourier transform infrared (FTIR) spectroscopic analysis was used to characterize structure-activity relationships of these NOS-containing thin films. We used cyclic voltammetry to determine the active enzyme concentration on the modified surfaces, and how this relates to enzymatic activity in terms of NO released fluxes from the thin films. Finally, we conduct platelet adhesion assays to determine if the amount of platelets adsorbed on the PEI/NOS films is affected by the amounts of NO released from these coatings.
Nanowire Organic Sensor for Ammonia Detection
Authors: Kilani Mohamed , Yu Xuecheng , Mao Guangzhao 
Published: May 2020

Ammonia is one of the largest produced chemicals with a global production of 150 million tons in 2017, expected to increase 8% in the next 4 years. It is widely used in several industries mainly in fertilizers manufacturing, but also in refrigeration systems, production of plastics, and as intermediates for pharmaceuticals synthesis. However, ammonia is highly corrosive and can damage cells in the body in contact, posing serious health risks. Despite the developments made in the detection systems, ammonia is still one of the most dangerous substances, responsible for the second highest number of chemical exposure casualties. The current detection solutions have serious limitations to be broadly used in industrial safety. Detection systems can generally fall under two categories, high-end equipment that is expensive, not user-friendly and can be only used in lab settings, and affordable devices that is prone to false alarms in a varying environment (humidity, temperature, etc.).
In this presentation, we will talk about the Nanowire Organic Sensor technology as an alternative solution platform for ammonia monitoring that is affordable and can provide real-time and wide-area coverage. Our patented technology is a room-temperature process based on electrochemical deposition which facilitates scalable manufacturing directly on substrates and devices. Compared with the existing nanowire sensor fabrication methods, out innovation has four main unfair advantages. 1) By direct deposit of a solution droplet, nanowires are created right on chips or micro-fabricated devices. 2) It is a room temperature fabrication process, thus enabling less complex and capital-intensive manufacturing process. 3) It is a modular method that enables combinatory synthesis of a wide range of new organic nanowires. 4) It is a fabrication technology compatible with flexible electronics platforms. We will show how the combination of the sensor arrays, impedance spectroscopy and artificial neural networks model enhances the selectivity in varying levels of humidity. We will also talk about how the technology is compatible with the internet of things technology and cloud services, and how the combination could be leveraged to ensure more flexible monitoring of ammonia for industrial safety.
Keywords: Electrochemical deposition, chemical sensing, nanomanufacturing.
Active and Stable Mxene Modified Cu2o Composite Films for Photoelectrochemical Water Splitting
Authors: Yilmaz Meltem , Handoko Albertus Denny , Anasori Babak , Seh Zhi Wei , Goh Gregory Kia Liang , Gogotsi Yury , Tang Junwang , Parkin Ivan P , Sankar Gopinathan 
Published: May 2020

Although limited in supplies and non-renewable, fossil fuels currently provide 80% of the global annual energy.1 Furthermore, the combustion of fossil fuels emits lingering gas emissions that exacerbates global warming.
Unlike fossil fuels, the solar energy is abundant, globally accessible and renewable, therefore developing technologies which can efficiently and sustainably harness and utilise this energy source is imperative. Solar-driven water splitting has been one of the most studied reactions because its product (H2) is a clean energy source with 4-fold higher mass energy density than fossil based fuels like gasoline. However, achieving good solar to hydrogen conversion efficiency (STH) in a single device remains a big challenge.
Cu2O is a very attractive photocathode material for the solar-driven water splitting as it has a narrow direct band gap of ca. 2 eV, which is capable to absorb most of the visible portion of the sunlight. It has favourable band positions for the hydrogen evolution reaction, with a theoretical 18% STH efficiency.2 However, one major drawback which limits the wider use of this material is its lack of stability in aqueous solutions when exposed to light.
In this study, we aim to introduce MXene’s as a cocatalyst on to Cu2O films. MXene’s are a family of 2-dimensional transition metal carbides, nitrides and carbonitrides. They have good electronic conductivity, good chemical stability and abundant active sites,3 making them a suitable co-catalyst for solar-driven water splitting reactions.
We observed a 3.7-fold increase in photocurrent density during photoelectrochemical (PEC) measurements at 0 V (vs. reversible hydrogen electrode) on MXene modified Cu2O compared to the plain Cu2O film. We also found that MXene addition, along with deposition of ZnO charge transfer layer, significantly improves the photo-stability of Cu2O photocathodes during simulated solar-driven water splitting reactions. We attribute this outcome mainly to the enhancement of the interfacial charge transfer and electrode photoconductivity upon illumination imparted by MXenes.
References
1 World Energy Counc., 2013, 1–28.
2 A. Paracchino, V. Laporte, K. Sivula, M. Grätzel and E. Thimsen, Nat. Mater., 2011, 10, 456–461.
3 M. Naguib, M. Kurtoglu, V. Presser, J. Lu, J. Niu, M. Heon, L. Hultman, Y. Gogotsi and M. W. Barsoum, Adv. Mater., 2011, 23, 4248–4253.