bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and Function Relationships of Heme-Based Gas Sensors and Heme-Redox Sensors
Authors: Shimizu Toru 
Published: February 2020

The heme-iron complex acts as the gas (O2, NO and CO)-sensing site in a heme-based gas sensor. This function is distinct from those of well-known heme proteins in which the heme-iron complex is the functional active center (e.g., the O2-carrying hemoglobin; the electron transfer mediator, cytochrome c; and the monooxygenase, cytochrome P450). The heme-based gas sensor, in contrast, is composed of an N-terminal heme-bound gas-sensing domain and a C-terminal functional domain. The association/dissociation of a gaseous molecule to/from the heme-iron complex of a gas sensor triggers the functional domain to regulate various physiologically important functions (e.g., guanylate cyclase activity, phosphodiesterase activity, histidine kinase activity, methyl-accepting chemotaxis, and transcription). There are also heme-redox sensors; they have the same domain arrangement as the heme-based gas sensors, and are regulated by the heme-iron redox state. Many of the molecular mechanisms underlying the intra- and inter-molecular signal transductions of gas and redox sensors have been elucidated. I summarize our existing knowledge of the heme-based gas (O2, NO and CO) sensors and heme-redox sensors. I then delineate the structure/function relationships and common characteristics of the bacterial, archaeal and mammalian heme-based gas sensors and heme-redox sensors.
Acknowledgements: This work was in part supported by Supported in part by Grants-in-Aid from Shantou University Medical College and from the National Natural Science Foundation of China (NSFC) (No. 31170736)
References: Martínková, M. et al.
J. Biol. Chem
. 288, 27702-27711 (2013); Shimizu, T.
Biosensors

3, 211-237 (2013); Igarashi, J. et al.
Handbook of Porphyrin Science
(Kadish, K. M. et al. Eds.) Vol. 15, Chap. 73, pp.399-460 (2011).
New Generation of Hybrid Materials Based on Hierarchical Assembly of Porphyrin on Supramolecular Scaffolds or Nanostructures
Authors: Fragalà Maria Elena , D'Urso Alessandro , Randazzo Rosalba , Cristaldi Domenico Andrea , Purrello Roberto 
Published: February 2020

Porphyrins multifunctional properties make these macrocycles intringuing building blocks to build up complex supramolecular assemblies via covalent or non-covalent approaches, either in solution or on inorganic surfaces. In the perspective of development of hybrids organic-inorganic materials, mastering of non-covalent strategies to transfer water soluble porphyrin based assemblies on nanostructured surfaces paves the way to a cost effective and environmentally friendly research that combine the unique properties of nanomaterials with the synthetic versatility of organic chemistry. Noteworthy, the control of spontaneous self-assembly is not trivial, as it is a hierarchically driven process that can proceed through thermodynamic or kinetic pathways. However, in water, complex porphyrin based supramolecular assemblies having a pre-determined and controlled stechiometry, chirality and composition have been successfully synthetized. Transfer of these assemblies (i.e. chiral porphyrin chiral aggregates, porphyrin-calixarenes, porphyrin-DNA) on inorganic surfaces opens the way to development of new generation of chiral surfaces and sensors, where porphyrins played an important role as spectroscopic probes, capable to overcome sensitivity limitations. Chirality induction and memory is, accordingly, another important requirement that need to be kept during this migration from solution to the solid state. The robustness of non-covalent approaches to achieve a straightforward, controllable and environmentally friendly functionalization of inorganic nanostructures strongly hinges on the competition between retention at the solid state rather than in solution and depends on several factors. Among them, polyelectrolytes secondary structure strongly influences the outcome of spontaneous deposition of porphyrin assemblies on solid surfaces often overriding the mere system electrostatics.
Synthesis of Benzoporphyrin-Diketopyrrolopyrrole Conjugates and Application for Organic Solar Cells
Authors: Kuzuhara Daiki , Takahashi Kohtaro , Yamada Naoya , Yamaguchi Yuji , Suzuki Mitsuharu , Aratani Naoki , Nakayama Ken-ichi , Yamada Hiroko 
Published: February 2020

Organic solar cells (OSC) have great attractive attention as key technology for next energy harvesting source. They could be fabricated for low cost, large area and flexible devices. However, power-conversion efficiency (PCE) of OSC is limited compared with the inorganic materials-base solar cell. Therefore, OSC requires new organic functional dyes for OSC for the improvement of PCEs. Benzoporphyrin (BP) has a expanded structure with four benzannulation at pyrrolic β-position on porphyrin core. BP has a highly planer structure and excellent semiconducting properties. Ono and colleagues　have developed the thermal-convertible precursors of BP, namely bicycle[2,2,2]octadiene-fused porphyrin (CP).
CP can be converted to BP under heating conditions by retro-Diels-Alder reaction. This thermal conversion method allowed us to fabricate the multi-layered OSCs by solution process. However, the nature of BP has the problems and limitations for improvement of the PCE because BP has weak absorption in the NIR regions and the HOMO level of BP is higher than that of ideal donor materials for OSC. It is known that improvement of the PCE is necessary for the wide-range absorption in the visible to NIR regions and appropriated HOMO and LUMO levels. In this presentation, we will report the design, synthesis and properties of the benzoporphyrin-diketopyrrlopyrrole conjugates (BP–DPP) for the p-type material of the PCEs. The absorption spectrum of BP–DPP was measured as thin film on glass substrate. The absorption of BP­–DPP shows broader absorption with four peak tops from visible to NIR regions. We have fabricated the bulk heterojunction (BHJ) type OSC with BP–DPP as p-type material and PC61BM as n-type material. The PCEs of 4.0% for BP–DPP:PC61BM was achieved with short-circuit current (J
SC) of 12.47 mA cm-2, open circuit voltage (V
oc) of 0.68 V, and fill factor (FF) of 0.47.We will also report the evaluations of film structures of these devices by AFM and XRD measurements.
Recovery of Erbium Metal Via Electrorefining in Room Temperature Ionic Liquids
Authors: Small Leo J. , Wheeler David R. , Lambert Timothy N. , Hess Ryan F. 
Published: February 2020

Erbium is a rare earth element with a variety of technologically important applications. Here we describe our efforts to develop room temperature ionic liquids specifically designed to facilitate electroplating of erbium metal from erbium chloride or erbium triflate, in an effort to recycle erbium waste converted into these salts. A variety of pyrrolidinium, ammonium, phosphonium, and chloroerbate ionic liquids are investigated. While all tested ionic liquids possess the required voltage window for theoretical erbium electroreduction, choice of chemistry is shown to drastically affect both incorporation of organics into the electrodeposited film, and the solubility of erbium salt in the ionic liquid, limiting deposition rates. A plan-view SEM micrograph of an amorphous erbium film electroplated onto platinum in butyltrimethylammonium bis(trifluoromethanesulfonyl)imide (BTMA NTf2) is shown in Figure 1. Analysis by energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy reveals incorporation of fluorocarbons into the film. These undesirable processes are not readily evident from the simple cyclic voltammograms (Figure 2). Detailed analysis of these CVs suggests reversible reduction of an intermediate followed by irreversible reduction to an erbium film contaminated with fluorocarbons.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Figure 1
Impact of Surface Texturization on Overall Performance of Mono-Crystalline Silicon Solar Cells
Authors: Sankarasubramanian Shrihari , Saud Gaurav Kumar , Shashikala M , Suratkar Prakash , Saravanan S 
Published: February 2020

Solar photovoltaics are amongst the foremost and most extensively studied sustainable energy systems. Silicon solar cells dominate commercial systems and hence bringing them ever closer to the theoretical efficiency is of vital importance. Technologists are continuously refining the manufacturing process to improve the efficiency of the cell while bringing down the cost.
The Silicon solar cell manufacturing is a complex process with many vital steps. Studies have shown the importance of steps like surface texturization[1], diffusion[2], antireflective coatings[3], making contacts[4] and metallization[5]. Amongst these the maximum impact on the final efficiency of the solar cell was found to come from the surface texturization[7]. This step creates surface features that improve light harvesting by the multi bounce approach. While heuristically it is understandable that the reduction in reflectivity would impact the cell performance, the present study aims to quantify this improvement.
To that end, two different processes were used to texture the mono-crystalline silicon wafers, the difference being the bath additives used. The studies were carried out on 125x125 mm mono-crystalline silicon (C-Si) wafers. The wafer reflectivity and texture uniformity were studied using a full spectrum colourimeter. The wafers were then processed into finished cells and the I-V characteristics of these cells were evaluated. The various performances characteristics of the cell were statistically analyzed to study there correlation to the reflectivity.

References:

P. Papet, O. Nichiporuk, A. Kaminski, Y. Rozier, J. Kraiem, J.F. Lelievre, A. Chaumartin, A. Fave, M. Lemiti, Sol. Energy Mater. Sol. Cells. 90, 2319–2328, 2006.

D. Kumar, S. Saravanan, P. Suratkar, J. Ren. Sus. Energy. 4(3), 33105-33113, 2012.

K. Coates, S. Morrison, S. Narayanan, A. Madan, in Proc. 16th Eur. Photovol. Sol. Energy Conf. Glasgow, 1279-1281, 2000.

P.S. Aakella, S. Saravanan, S.S. Joshi, C.S. Solanki, Sol. Energy. 97, 388-397, 2013.

M.M. Hilali, K. Nakayashiki, C. Khadilkar, R.C. Reedy, A. Rohatgi, A. Shaikh, S. Kim, S. Sridharan, J. Electrochem. Soc. 153(1), A5-A11, 2006.

J. D. Hylton, A. R. Burgers,W. C. Sinke, J. electrochem. Soc., 151 (6) G408-G427 (2004).

Figure 1
Transient Photocurrent in Organic Photocells Assisted By Electric Double Layers in Electrolytes
Authors: Odaka Masato , Matsushita Michio M , Awaga Kunio 
Published: February 2020

Recently, there has been increasing interest in photoelectric conversion by organic semiconductors. Organic materials have many advantages over inorganic materials, such as the possibility of low temperature, and thus low cost processing, which allows for flexible architectures to be realized. However, to date, organic device performance still lags behind that of inorganic devices. It is our aim to use the intrinsic properties of organic materials to develop novel operation principles for organic devices, to rival the performance of inorganic devices.
In previous works, our group has reported on anomalous transient photocurrents induced by a multi-layer photocell architecture, which incorporates a polarizable insulating layer to aid charge separation in the active semiconductor layer. More recently, we reported the use of ionic liquids as the insulating layer. Such architectures generate a time-varying (transient) response to continuous illumination, which may have an application to optical communication. In these devices, The electric double layers in ionic liquid enhance the charge separation in the active layers and generate an anomalous transient photocurrent.
In this work, we adopted the KCl aqueous solution to the insulating layer, instead of ionic liquids. Figure.1 shows the transient photocurrent with several concentration KCl aqueous solutions. The transient photocurrent was obtained ever with a small amount of KCl. Furthermore, there is a concentration dependence of the peak values and the relaxation times of the transient photocurrents.

Figure 1
A Novel Approach to Study the Chemo-Mechanical Stability of the Solid Electrolyte Interphase (SEI) in Lithium-Ion Batteries
Authors: Kumar Ravi , Xiao Xingcheng , Lu Peng , Sheldon Brian W. 
Published: February 2020

It has been recognized that a stable solid electrolyte interphase (SEI) is critical in operation of rechargeable Li-ion batteries. A clear understanding of SEI formation, evolution and mechanical response will make it possible to tailor better passivation layers that can improve battery performance. In this work we present a novel approach that is based on patterned Si islands, with measurements that include galvanostatic cycling, electrochemical impedance spectroscopy (EIS), in situ optical microcopy, and in situ stress measurements. By calibrating the expansion and contraction of these islands, it is possible to systematically investigate the impact that large volume changes have on the SEI stability. Comparisons between these islands and continuous Si films then make it possible to correlate the irreversible capacity loss with expansion strain in the underlying Si. These galvanostatic experiments on island samples provide a novel mechanical testing configuration for investigating the stability of thin SEI layers.
In-Situ Raman Spectroscopy of Sulfur Speciation in Lithium-Sulfur Batteries
Authors: Wu Heng-Liang , Huff Laura A. , Gewirth Andrew A. 
Published: February 2020

In this talk we report on our use of in-situ Raman spectroscopy and cyclic voltammetry to investigate the mechanism of sulfur reduction in lithium-sulfur battery slurry cathodes. Raman spectroscopy shows that long chain polysulfides (S8
2-) were formed via S8 ring opening in the first reduction process at ~2.4 V vs Li/Li+ and short chain polysulfides such as S4
2-, S4
-, S3
․
- and S2O4
2- were observed with continued discharge at ~2.3 V vs Li/Li+in the second reduction process. Elemental sulfur can be reformed in the end of the charge process. (1-4)
Rate constants obtained for the appearance and disappearance polysulfide species shows that short chain polysulfides are directly formed from S8 decomposition. The rate constants for S8 reappearance and polysulfide disappearance on charge were likewise similar, suggesting that polysulfide oxidation and reduction is quasi-reversible. The formation of polysulfide mixtures at partial discharge was found to be quite stable. We also examined the effect of CS2 addition on the sulfur reduction mechanism. Electrochemical and Raman results show that CS2 stabilizes the S8
2-product and inhibits further discharge of the cell

References:

(1) Barchasz, C. et al., Anal. Chem. 2012, 84, 3973.
(2) Cuisinier, M. at al., J. Phys. Chem. Lett. 2013, 4, 3227.
(3) Yeon, J.-T. et al., J. Electrochem. Soc. 2012, 159, A130.
(4) Hagen, M. et al., J. Electrochem. Soc. 2013, 160, A1205.
Electrochemistry of Sodium Nonatitanates in Lithium and Sodium Ion Batteries
Authors: Shirpour Mona , Seshadri Dhruv , Doeff Marca 
Published: February 2020

Sodium nonatitanate, NaTi3O6(OH)·2H2O, readily undergoes electrochemical sodium and lithium insertion reactions at unusually low potentials.[1] The lower average insertion potential and higher theoretical capacity (~300 mAh/g) suggest that it could be a higher energy density alternative to the well-known anode material Li4Ti5O12.[2-3] Titanates are also denser materials than graphite, so full utilization of titanates in a lithium-ion cell should lead to a somewhat higher energy density. This presents an intriguing possibility of using high-energy anodes based on titanate materials for lithium and sodium ion batteries, provided they could be developed further.
The presence of mobile sodium ions in the lithium ion system is undesirable from a performance and safety point of view. A recent NMR study [4] on composite electrodes derived from sodium nonatitante cycled in lithium cells showed evidence of in situ sodium plating during the discharge process. Our ex situ and in situ synchrotron XRD diffraction patterns [5] suggest that mobile sodium ions undergo ion-exchange with the electrolytic solution and/or are de-intercalate upon recharge, then subsequently are reduced to metallic sodium at the very low potentials encountered during later discharges. We show that a simple ion-exchange process prior to incorporation in electrochemical cells removes all sodium ions, producing the lithiated form of the material. The lithiated material performs similarly to sodium nonatitanate in lithium cells, although coulombic inefficiencies are somewhat higher (Figure 1). A comparison is made between the structure and electrochemical behavior of sodium nonatitanate and the lithiated analog in lithium cells.
References
1. M. Shirpour, J. Cabana, and M. Doeff, Energy & Environmental Science, 2013, 6(8), 2538-2547.
2. Z. Yang, D. Choi, S. Kerisit, K. M. Rosso, D. Wang, J. Zhang, G. Graff and J. Liu, Journal of Power Sources, 2009, 192, 588–598.
3. D. Deng, M. G. Kim, J. Y. Lee and J. Cho, Energy & Environmental Science, 2009, 2, 818–837.
4. Mallory Gobet, PhD thesis, Department of Physics and Astronomy, Hunter College of CUNY, New York, 2014.

5. D. Seshadri, M. Shirpour, M. Doeff, Journal of The Electrochemical Society, 2014, 162 (1) A1-A8.

Figure 1
Evaluation of Si Based Composite Helices Used As Anodes in Lib
Authors: Polat Deniz Billur , Keles Ozgul 
Published: February 2020

Films with helices made of various Cu-Si atomic ratios (10-90%, 20-80%, 30-70%) were fabricated by an ion-assisted glancing angle co-deposition technique. The effect of Cu/Si atomic ratios on the morphologies and the structures were studied by SEM and XRD. The use of those helices as anode materials in lithium ion batteries were evaluated by galvanostatic test results.
The SEM analyses demonstrated that during the co-evaporation an increase in Cu/Si atomic ratio decreased the thickness of the helices, increased the tilting angle and decreased the homogeneity in the thin film morphology. The best performance was achieved when 20%at. Cu containing SiCu helical shaped thin film is used as anode material.

Keywords: Anode, thin film, helices, ion assisted glancing angle depositon, electron beam.
Phase-Transition Mechanism Investigations in Monoclinic Li2FeSiO4 Orthosilicate Cathode
Authors: Lu Xia , Arthur Zachary , Wei Huijing , Chiu Hsien-Chieh , Chen Ning , Zhou Jigang , Reid Joel , Jiang De-Tong , Gauvin Raynald , Zaghib Karim , Demopoulos George P. 
Published: February 2020

Lithium transition metal silicates Li2

M
SiO4 (
M
= Fe, Mn, Co, etc.)1
, 2, well-known for their 2-Li theoretical capacity, draw increasingly more attention. In this text, we propose a hydrothermal method3
to obtain phase-pure nanoscale lithium iron silicate Li2FeSiO4 for probing its electrochemical performance as Li-ion battery cathode. Two types of Li2FeSiO4 crystals are prepared, namely low-temperature monoclinic phase and high-temperature orthorhombic phase and their electrochemical performance is found to be strongly structure-depended. As a result, the electrochemistry-structure relationships are systematically investigated using in-situ synchrotron XRD/XANES characterizations and first-principles calculations. The results demonstrate that there are obvious phase transitions for the metastable monoclinic Li2FeSiO4 electrode upon cycling4 and the Li ion has poor diffusion kinetics with activation energy of minimum 0.80 eV in both structures. Furthermore the charge compensation mechanism is discussed by XANES and calculations in monoclinic Li2FeSiO4 structure for more than one Li extraction. All of these findings reveal some missing links in our fundamental comprehension of these materials and provide ideas for designing/obtaining improved silicate cathode materials.
References
1. Nyten, A., Abouimrane, A., Armand, M., Gustafsson, T. & Thomas, J. O. Electrochemical performance of Li2FeSiO4 as a new Li-battery cathode material. Electrochem. Commun.
7, 156-160, (2005).
2. Gummow, R. J., He, Y., Recent progress in the development of Li2MnSiO4 cathode materials. J. Power Sources,
253
, 253, 315-331 (2014).
3. Wei, H.J. et al. Synthesis and Characterization of Li2FeSiO4 as Candidate High-Capacity Li-ion Battery Cathode Material. 227th ECS Meeting, May 24-28 (2015), Chicago, Illinois, USA.
4. Xia Lu, Huijing Wei, Hsien-Chieh Chiu, Raynald Gauvin, Pierre Hovington, Abdelbast Guerfi, Karim Zaghib and George P. Demopoulos, Rate-dependent phase transitions in Li2FeSiO4 cathode nanocrystals, Sci. Re. in revision (2014).
Phase Field Simulation of Lithium Ion Diffusion in Solid Electrolyte Interface
Authors: Guan Pengjian , Liu Lin 
Published: February 2020

Silicon materials have been recognized as one of the new electrode materials in the next generation of lithium ion batteries (LIBs) with high energy density and large specific capacity. However, there is still a significant limitation to use the silicon based composite electrodes since the fracture occurs as a result of the huge volume change and fast lithium diffusion during the electrochemical lithiation process. A stable solid electrolyte interface (SEI) can help prevent fraction. However, the lithium diffusion inside SEI layer is still not fully understood. In this study, we focus on two dimensions (2-D) lithium diffusion simulation inside SEI layer with considering its morphology evolution. Our previous research (1) has proven that SEI morphology evolution can be regarded as a solification process, and phase field method shows great advantage to deal with the solification problem. The phase field variable is applied to simulate the SEI morphology evolution without tracking the multiple interfaces directly. The detailed chemistry of SEI species formation reaction has not been considered in the phase field modelling. The simulation assumes that SEI is composed of hydrocarbons, PEO-type oligomers, LiF, LixPFy, and LixPFyOz products based on the XPS experiments in the literature. We apply different formation contact angles to represent the different surface energy of different SEI specis. We are able to track different material species in SEI layer with defining the properties of each species for lithium diffusion simulation. In this work, a new model will be developed to simulate lithium diffusion during SEI growth and its morphology evolution based on our previous research and the computational method reported Han’s work (2). The concentration field can be regarded as a conserved property during the long-range diffusion. Therefore, the Cahn-Hilliard equations can be applied to formulate the phase transformations and description of diffusion inside the silicon based electrode. The chemical potential can be achieved by driving the total free energy equation. And the flux, which is assumed to be proportional to the gradient of the diffusion potential, can be presented by Fick’s Law. With the combination of the Cahn-Hilliard formulation and Fick’s Law, we are able to predict the lithium diffusion coefficient and lithium concentration distribution inside SEI layer. With the improvement of the current model, it is expected that the understanding on lithium diffusion inside SEI layer could be advanced to more accurately predict the fracture of silicon based composite electrodes during the electrochemical lithiation process. In addition, the developed model could be applied to other interface region problems and it has great potential to be extended to three-dimensions.
1. P. Guan, X. Lin and L. Liu, ECS Transactions, 61, 29 (2014).
2. B. C. Han, A. Van der Ven, D. Morgan and G. Ceder, Electrochimica Acta, 49, 4691 (2004).