bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergistic Effect of Cobalt Nanoparticles Embedded in Nitrogen-Doped Carbon As a Pt Alternative Electrocatalyst for Dye-Sensitized Solar Cells
Authors: Ahn Sung hee 
Published: February 2020

Dye-sensitized solar cells (DSSCs) are an attractive, innovative energy conversion device because of several distinctive benefits that are hardly obtainable from other next-generation solar cells. A typical configuration of DSSCs includes a nanoporous TiO2 anode sensitized with an inorganic complex, an electrolyte containing I-/I3-couple, and a counter electrode (CE). Platinum (Pt) has been preferred most as an electrocatalyst for the CE, because it possesses excellent properties such as a low charge-transfer resistance, a high electrical conductivity, high transmittance. However, the scarcity of Pt and the resulting cost issue has stimulated research to develop low-cost, earth-abundant materials as Pt alternatives in recent years. A wide variety of materials including metal chalcogenides, oxides, nitrides, and carbides have been explored to date.
In this work, we extend the choice of Pt alternatives up to a metal/carbon composite material and elucidate the hidden mechanism of electrocatalytic activity of this novel catalyst. A fast, large-scalable synthesis route via calcination of zeolitic imidazolate framework-67 (ZIF-67) is developed to obtain N-doped carbon incorporated with Co metals (Co/N-C). 2-methylimidazole coordinating to cobalt ions serves as an excellent carbon source that allows for high incorporation of N atoms within carbon lattice. In addition, in situ reduction of the cobalt ions aids in increasing graphitic nature of Co/N-C. Our in-depth electrochemical investigation including cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements revealed that the electrocatalytic activity of Co/N-C catalyst toward the reduction of I3- is superior to that of traditional Pt counterpart. When employed for the CE material, the DSSCs equipped with the Co/N-C catalyst outperform those fabricated with Pt: the power conversion efficiency of 8.06% is obtained as compared to Pt CE (7.52%). Our study also provides a new sight into this metal/carbon composite catalyst: the Co nanoparticles embedded in the carbon significantly promote the electrocatalytic activity of N-doped carbon. The stability of the Co/N-C catalyst was investigated to ensure the long-term use, revealing that Co/N-C is substantially more resistive against corrosion by the I-/I3- couple, rendering excellent stability to Co/N-C.
Effect of Thermal Treatment of Poly(amide imide) Binder on Cycling Performance of Silicon Alloy-Based Anode for Lithium-Ion Battery
Authors: Kim Sang-Hyung , Yang Hwi Soo , Yook Seung Hyun , Kim Seon-Kyong , Park Cheol-Ho , Choi Hae Young , Kim Dong-Won 
Published: February 2020

The growing demand for high-performance rechargeable lithium-ion batteries for applications such as portable electronic devices, electric vehicles and energy storage systems requires remarkable improvement in the energy density. It has led to the search for advanced materials with high theoretical specific capacities, which should be abundantly available for large-scale applications. Silicon-based anode materials with high theoretical capacity, low reduction potential and low cost satisfy these requirements for next-generation lithium-ion batteries. However, the silicon materials undergo large volume changes during the alloying/de-alloying reaction, resulting in pulverization of the electrode. In addition, the large volume expansion results in the continuous breakdown and formation of solid-electrolyte interphase (SEI) layer during the repeated cycling. To mitigate the volume change, many studies have been carried out by different approaches such as fabricating thin films, reducing particle size, employing Si alloy materials and using strong binder. It is well known that binders are critical to maintain the electrode structure and capacity retention. Different binders for Si-based anodes developed to date include carboxymethyl cellulose (CMC), poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), poly(amide imide)(PAI) and polyimide (PI). Among them, thermally-treated PAI has high mechanical strength and good adhesion, enhancing the electric contact with current collector. In this study, we report electrochemical characterization of Si alloy materials with thermally-treated PAI as a binder. Furthermore, we analyzed binding mechanism of PAI, with changing heat treatment temperature. A detailed investigation and evaluation of cycling performances are performed by XPS, FT-IR, electrochemical impedance spectroscopy, peel test and galvanostatic cycling test.
Biomolecule Detection Using a Resonant Capacitive Sensor
Authors: Bane Danielle , Subramanyam Guru , Hansen Karolyn M. 
Published: February 2020

Biomarker detection is of paramount importance to the medical community for the assessment of health and human performance. Two biomarkers of interest are orexin A (a biomarker of cognitive function) and trimethylamine (a biomarker of the disease trimethylaminuria). For the purpose of orexin A and trimethylamine detection, resonant capacitive sensors with a peptide functionalized guanine dielectric layer are designed and fabricated, Figure 1. The molecular recognition peptides, Table 1, selectively capture the biomarkers. The binding of the biomarkers to the peptides changes the permittivity of the dielectric layer resulting in a significant shift in the resonant frequency, amplitude, and phase of the sensors thereby indicating the biomarkers’ presence.
Due to the limited utilization of guanine in electronics, the first objective in designing these sensors has been guanine characterization. For characterization purposes, guanine was deposited as the dielectric layer in a capacitive test structure (CTS), and from these structures, the dielectric constant and loss tangent of guanine was determined by comparing the measured scattering-parameters (S-parameters) to an electrical model of the device. Subsequently, guanine was deposited as the dielectric for the resonant capacitive sensor to determine the resonance of the guanine-integrated structure and to serve as the sensor platform.
After guanine characterization, the next objective is to investigate methods for peptide functionalization. The two methods of interest are spin-coating and chemical tethering (preferred). In order to be successful, the peptides must adhere to the guanine in a manner that does not interfere with the biomarker binding sites. The chemical tethering method offers a way to covalently cross-link the peptides to the guanine, but the spin-coating is less likely to interfere with the peptides’ binding sites.
After determining a functionalization method, the guanine will be functionalized with peptides using this method.
The final objective is to test the fabricated sensors. For testing, the S-parameters are measured to determine the resonance of the sensors pre-exposure (baseline) and following exposure to positive (orexin A in aqueous phase and trimethylamine in vapor phase) and negative controls.

Acknowledgements: Support was provided through the Dayton Area Graduate Studies Institute Fellowship, and the Air Force Research Laboratory (Human Effectiveness and Materials and Manufacturing Directorates).

References

[1] J. Hagen, W. Lyon, Y. Chushak, M. Tomczak, R. Naik, M. Stone, and N. Kelley-Loughnane, “Detection of orexin a neuropeptide in biological fluids using a zinc oxide field effect transistor,” ACS Chemical Neuroscience, vol. 4, no. 3, pp. 444–453, 2013.
[2] Y.-R. L. Tzong-Zeng Wu and E.-C. Chan, “Exploring the recognized bio-mimicry materials for gas sensing,” Biosensors and Bioelectronics, vol. 16, no. 9-12, pp. 945-953, 2001.

Figure 1
XPS and FTIR Studies of Dual Target Sputtered Bcn Thin Films
Authors: Prakash Adithya , Sundaram Kalpathy B 
Published: February 2020

The ever increasing advancements in semiconductor technology and continuous scaling of CMOS devices mandate the need for new dielectric materials with low-k values. The interconnect delay can be reduced not only by the resistance of the conductor but also by decreasing the capacitance of dielectric layer. Also cross-talk is a major issue faced by semiconductor industry due to high value of k of the inter-dielectric layer (IDL) in a multilevel wiring scheme in Si ultra large scale integrated circuit (ULSI) devices. Recently it has been found that Boron Nitride (BN) films can achieve low-k values around and hardness comparable to diamond [1][2]. BN is hygroscopic in nature. In this respect carbon can be added to the BN structure to produce Boron Carbon Nitride (BCN) films as the possible substitute for BN. The minimum dielectric constant achieved by plasma assisted chemical vapor deposition for a BCN thin film was reported to be 1.9. [2] The BCN films are also instrumental in suppressing the Cu migration [3]. The Young’s modulus of BCN films are reported well above 20 GPa making it one of the suitable options for low-k materials [4].
In the present work, BCN films were deposited by dual target sputtering of boron carbide (BC) target (DC), boron nitride (BN) target (RF) in nitrogen ambient with argon. The films were deposited under various N­2/Ar gas flow ratios and temperature. XPS and FTIR measurements were performed to find the relative chemical compositions, chemical bonds and behavior of the deposited films with respect to change in N­2/Ar gas flow ratios and deposition temperature.
REFERENCES
[1] Jun Liu, Kian Ping Loh, Ming Lin, Yong Lim Foo, Wei De Wang, and Dong Zhi Ch, Journal of Applied Physics, 96 (2004) 6679.
[2] Riedel R., Advanced Materials, 4 (1992) 759.
[3] M. K Mazumder, R. Moriyama, D. Watanabe, C. Kimura, H. Aoki, and T. Sugino: Jpn. J. Appl. Phys. 46 (2007) 2006.
[4] C. Morant, D. Caceres, J. M. Sanz, and E. Elizalde: Diamond Relat. Mater. 16 (2007) 1441.
Evaluation of Dynamic Hydrophobicity of Nanoporous Silicon Surfaces Prepared By Metal-Assisted Chemical Etching
Authors: Machida Kenta , Asoh Hidetaka , Yoshida Naoya , Okura Toshinori , Ono Sachiko 
Published: February 2020

Wettability is one of the important properties of solid surfaces from both fundamental and practical aspects. Among various factors, surface energy and roughness are the dominant factors for the wettability. Static wettability, that is, water contact angle (WCA) has been commonly used as a criterion for the evaluation of hydrophobicity of solid surface. In recent years, WCA can be designed easily by controlling surface energy and roughness based on Young’s, Wenzel’s, and Cassie’s equations. On the other hand, dynamic wettabilities such as sliding property on the hydrophobic surface are poorly undersutood. Although water sliding angle (WSA: the critical angle where a water droplet with a certain weight begins to slide down the inclined plate) and contact angle hysteresis (the cosine of receding contact angle minus that of advancing contact angle) are often measured to evaluate the water-repellent property of the hydrophobic surface, comprehensive understanding of the water-repellent properties is still limited because the relationships between the WSA and the WCA are not clear [1-2]. In this study, we used nanoporous silicon surfaces with different surface morphologies, which were formed by metal-assisted chemical etching using Ag nanoparticles, as a solid surface. Static and dynamic wettabilities of their surfaces were investigated with focusing on the influences of pore size and surface roughness on wettability of porous silicon surfaces.

p-type silicon (100) substrates were immersed in a mixed solution of 2×10-2 mol dm-3 AgNO3 and 5 mol dm-3 HF to deposit Ag particles on the entire surface of silicon substrates. After deposition of Ag particles, silicon substrates were immersed in a mixed solution of 10 mol dm-3 HF and 1 mol dm-3 H2O2at room temperature at different time. SEM images of obtained porous silicon after etching with different surface roughness are shown in Fig. 1. WCAs (approximately 135°) of etched silicon were higher than that of flat silicon (75°), presumably due to decrease of contact area between porous structure and droplet based on Cassie’s model. Although surface roughness increased with increasing etching time, however, WCAs of etched silicon were about the same (135°) despite the difference in surface morphologies (Fig. 1a-c). On the other hand, WSAs increased with increasing surface roughness. The changes in WSAs were thought to be caused by the pinning effect generated by increase of pore diameter and surface roughness during chemical etching. These results indicate that WSA is affected more significantly by physical inhomogeneity such as surface roughness of the etched surface than WCA.
[1] M. Miwa, A. Nakajima, A. Fujishima, K. Hashimoto, T. Watanabe, Langmuir,
16, 5754-5760 (2000).
[2] S. Suzuki, A. Nakajima, Y. Kameshima, K. Okada, Surface Science Letters,
557, L163-L168 (2004).

Figure 1
Studies on the Effects of Angle of Incidence on the Optical Reflecftance Properties of Silicon Nanowires Grown By Electroless Etching
Authors: Velez Victor H. , Mertens Robert George , Sundaram Kalpathy B 
Published: February 2020

Silicon nanowires (SiNW’s) arrays prepared by electroless etching method can significantly suppress light reflection across the visible spectrum [1]. The decrease in reflectivity is evidently due to optical absorption in the silicon. The nanowires scatter the incident light by reflection, refraction, and diffraction processes, and the light will interact with several nanowires until it is either absorbed by a nanowire or the substrate, or is reflected by the sample [2]. However, the Fresnel reflection predicts a large reflectance at a large angle of incidence (AOI) [3]. For effects of comparison, the reflectance versus wavelength data using visible light on SiNW’s grown by eletroless etching in three different concentrations of Hydrofluoric Acid (HF) and Silver nitrate (AgNO3) for different etching times at room temperature have been provided at different AOI values. In general, SiNW’s exhibit low reflectance over a wide range of AOI. SiNW’s etched with high concentration of AgNO3 produce low reflectance. These results are beneficial to the design and fabrication of nanowire-based optoelectronic devices.
In this experiment a Cary 100 UV-Visible Spectrometer was used for reflectance analysis and silicon (Si) wafers were dipped for 15, 30, 45 and 60 minutes at room in an electroless solution prepared in a petri dish containing silver nitrate (AgNO3) and hydrofluoric acid (HF) [4].
U.S. Department of Energy Hydrogen and Fuel Cell Tech-to-Market Activities and National Laboratory Impact Initiatives
Authors: Satyapal Sunita , Ainscough Chris , Weber Adam Z , Malhotra Sanjiv , Papageorgopoulos Dimitrios C , Farmer Rick 
Published: February 2020

Hydrogen and fuel-cell technologies offer the potential to reduce emissions and petroleum dependency dramatically across transportation, stationary, and portable power sectors of the economy. Global revenues for fuel cells surpassed $1.3 billion in 2013, with market estimates of more than $100 billion within two decades. Thousands are already being adopted for material handling equipment by household names such as WalMart, Coca-Cola, BMW, FedEx, Sysco among many others and for mission-critical applications such as telecom towers by leading global entities including Sprint. Increased emphasis on hydrogen and fuel cells is anticipated as major automakers roll out fuel-cell electric vehicles (FCEVs) with Toyota releasing their first (named Mirai − which means ‘future’ in Japanese) for commercial sale, Hyundai already leasing theirs, and Honda, GM and others close behind.
With recent increased activity in hydrogen and fuel-cell technologies, the U.S. Department of Energy (DOE) is amplifying its efforts to engage the U.S. DOE national laboratory enterprise in accelerating progress. In this talk, we will discuss FCTO’s strategy and implementation opportunities for increasing the engagement and effectiveness of national labs with U.S. industry, including increasing and enhancing lab-private sector relationships, streamlining access to national-lab capabilities, and demonstrating the value of lab-developed science and technology.
This presentation will also provide an overview of progress to date and additional needs, with a focus on stakeholder feedback to continue to improve DOE FCTO programs. FCTO funding has already led to over 500 patents, forty commercial hydrogen and fuel-cell technologies in the market and sixty-five emerging technologies anticipated to be commercial in the next 3 to 5 years. National labs have received more than 200 patents related to hydrogen and fuel cells and are working closely with companies and universities to continue addressing key challenges.
Finally, this presentation will provide an overview of technical capabilities at various national labs, examples of mechanisms to engage with national labs and examples that ‘demystify’ the process of working with national labs. Both fundamental electrochemistry related capabilities as well as modeling, analysis, and testing capabilities will be summarized. In addition, mechanisms such as FCTO’s successful use of the Technology Transfer Opportunity (TTO) through the Small Business Innovation and Research (SBIR) program will be discussed as well as the emerging Small-Business Voucher (SBV) program. FCTO will present its strategy of using lab-led consortia in key areas and including universities and industry as project partners. Future plans including engagement of the investor community and accelerating technology to market in key areas across hydrogen production, delivery, storage and fuel cells will be covered.
The Center for Electrochemical Energy Science (CEES): An Overview
Authors: Fenter Paul 
Published: February 2020

The Center for Electrochemical Energy Science (CEES) seeks to develop a fundamental understanding of the lithium ion electrochemistry of oxides in lithium ion battery systems. Controlling electrochemical reactions is a significant challenge, due to the extreme structural and chemical changes that take place as lithium ions are incorporated in the active electrode material. We are approaching this through coordinated studies of three types of lithium ion chemistries with a focus on oxide electrodes: 1) Insertion reactions (e.g., Li + M-O ↔ LiM-O) into a host oxide matrix; 2) Conversion reactions (e.g., 2Li + M-O ↔ M + Li2O) that disrupt the oxide lattice upon lithiation, leading to phase separation of the metal and Li2O phases; and 3) “Hybrid” Li-O2/Li-ion reactions (e.g., 4nLi+ + nO2 + MOy ↔ (Li2O)2nMOy) that involve disruption of the host lattice, along with insertion of Li and O. Specifically our primary focus is on studies of well-defined model systems that enable a fundamental understanding of these reactions. One broad theme in these studies is the role of interfaces in these reactions. I will also review recent work in which we seek to isolate and understand the role of interfacial reactivity in these systems through in-situ, real-time, observations of lithiation reactions of well-defined model electrode-electrolyte interfaces using X-ray reflectivity. These results reveal novel insights into the role of interfacial reactivity in conversion reactions (e.g., Si, CrOx, NiO) that can be used to control the complex reaction lithiation pathway through the use of thin-film and multilayer electrode structures.
Acknowledgment: This work was supported as part of the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. The work was done in collaboration with T. Fister, S. S. Lee (ANL), J. Esbenshade, B. Long, A. Gewirth (University of Illinois at Urbana-Champaign), X. Chen, G. Evmenenko, M. Bedzyk (Northwestern University).
Center for Mesoscale Transport Properties: Probing the Limits of Electron and Ion Transport over Multiple Length Scales
Authors: Marschilok Amy C 
Published: February 2020

The mission of the EFRC is to understand and to ultimately control transport properties in complex battery systems with respect to multiple length scales, from molecular to mesoscale (m
2
m); to minimize heat and maximize work of electrical energy storage devices. Thus, we are probing the factors limit of ion and electron transport and electron transfer over multiple length scales.
This presentation will focus on several of the parameters affecting active materials. Several materials classes are under investigation including 1D, 2D and densely packed structures. The impact of the active material size and morphology on electrochemical behavior is probed through preparation of samples through direct synthetic manipulation of the material properties. The intrinsic electrochemical properties of active materials without the complexities of composite electrodes were probed through development of electrochemical measurements of individual particles. Additionally, the detailed analysis and role of structural defects on electrochemical performance will be presented. The information gained will provide necessary information for the design of next generation energy storage devices.
Understanding the Layered Oxides for High-Voltage Intercalation in Alkaline Ion Batteries
Authors: Meng Shirley 
Published: February 2020

Among all candidates of positive electrode materials for lithium ion batteries, the layered oxides have gained growing research interest in recent years, especially the Ni rich layered oxides and the mixed transition metal (Ni,Co,Mn) layered oxides. They can reach more than 220mAh/g capacity when charged above 4.5V, making them one of the highest energy density positive electrode materials among all known intercalation compounds for cathode materials. [1] Being the source of major capacity improvement, the high voltage operation (>4.5V), on the other hand, also cause unexplained phenomena in these layered oxides. In classical layered oxides, the transition metal (TM) oxide host TMO2should retain its host structure during initial discharging–charging, while lithium ions are intercalated–de-intercalated from the host. In contrast, recent studies suggested that after high voltage operation in layered oxides, certain amounts of transition metal ions migrate from the transition metal layers to lithium layers. Our previous work [2] has suggested that the migration may be assisted by oxygen vacancies generated in the late charging states (high voltages), but three critical questions remain unanswered: (1) how can we visualize and quantify the change in structure and chemical content at the atomic level (2) what is the oxygen activity upon high voltage and how does it assist transition metal migration and (3) what are the impact of these high voltage phenomena on rate capability and long-term cycling.
LiNi0.8Co0.15Al0.05O2 (NCA), LiNi1/3Co1/3Mn1/3O2 (NCM333) and LiNi0.5Co0.2Mn0.3O2(NCM523) are used as model compounds for the in-depth study. Figure 1 and Table 1 summarize the electrochemical properties of NCA and NCM333 and 532.
A suite of powerful experimental tools and computational tools has been deployed. To probe the bulk structural change, morphological and chemical changes, we combined X-ray diffraction (XRD), Neutron diffraction (ND), Pair Distribution Function (PDF) analysis, Electron Energy Loss Spectroscopy (EELS) and Transmission X-ray Microscopy (TXM), analytical Transmission Electron Microscopy (TEM). We will reveal and discuss the factors that determining the high voltage stability of oxides materials in alkaline ion batteries.

Acknowledgements

This work is supported by the NorthEast Center for Chemical Energy Storage (NECCES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Basic Energy Sciences, with Award Number DE-SC0012583.

Reference

1) Z. H. Lu, D. D. MacNeil and J. R. Dahn, Electrochem. Solid- State Lett., 2001, 4, A191–A194
2) K. J. Carroll, D. Qian, C. Fell, S. Calvin, … and Y. S. Meng, Phys. Chem. Chem. Phys., 2013 15, 11128

Figure 1