bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Nature of Silver Halide Underpotential Deposition on Au(111)
Authors: Phillips Jesse A. , Morgan Heather , Jackson Lauren E. , Jones Greg H. , Iski Erin V. 
Published: February 2020

In previous research completed by Iski et al.1, it was found that through specific electrochemical methods, a silver (Ag) monolayer could be formed on a Au(111) surface in both a chloride-free and chloride-rich solution. The electrochemical method used was under potential deposition (UPD) and reduced Ag+ to the surface. The previous study showed that, in a chloride-free environment, the Ag monolayer could be formed and atomically resolved; however, once removed from the cell, it could be completely destroyed via hydrogen flame annealing. Interestingly, in the presence of chloride, the same Ag monolayer was formed and was found to be extremely thermally stable after removal from the cell and was resistive to temperatures as high as 1,000 K. The atomic structure of these films can be studied with electrochemical scanning tunneling microscopy (EC-STM), which not only allows for atomic scale imaging of the surface layer within an electrochemical environment, but also facilitates the taking of cyclic voltammograms (CVs), which can be used to examine the redox behavior of the systems. Through this electrochemical manipulation, a newly hypothesized mechanism for the reduction of AgCl to the surface rather than bare Ag+ ions is proposed. Despite many studies on these types of surface layers2, very few publications have directly studied their extreme thermal stability. Since it is known that the stability of bulk metal halide structures decreases as the halogen ion increases in size, an investigative study was performed following the same procedure, substituting chloride with bromide and iodide. As with the AgClx system, once AgBrx was used to form the Ag monolayer, a new surface structure formed which was also thermally resistive to a hydrogen flame. Conversely, the surface formed by the AgIx was not maintained and formed silver oxide insulating species after thermal treatment. CVs taken in the same region as those of the previous work show a definite surface modification by both AgBrx and AgIx before annealing which persists after the thermal treatment for the AgBrx. Further electrochemical studies into these Ag monolayers formed in a halogenated environment are being conducted in an attempt to better understand the properties of these surfaces and the type of redox chemistry occurring at the relevant potentials. Using EC-STM, we plan to study the ways in which this remarkable stability is imparted to the single crystal surface under ambient conditions.
[1] Iski, E. V. et al. Electrochimica Acta
2011, 56 (3), 1652–1661.
[2] Michalitsch, R.; Laibinis, P. E. Angewandte Chemie International Edition
2001, 40 (5), 941–94.
Synthesis and Characterization of Green Emitting Erbium Doped BaY2ZnO5 Nanophosphors
Authors: Taxak Vinod Bala 
Published: February 2020

Green emitting Erbium doped photoluminescent nanophosphor for light emitting materials

V.B. Taxak1*, Sangeeta Chahar1

1Department of Chemistry, Maharshi Dayanand University, Rohtak -124001, India
*Corresponding Author: Tel: +919466722544
E-mail : v_taxak@yahoo.com
In this present era of nanotechnology, rare earth doped nanophosphors in nano dimension marks as thrust area of research owing to its magnificent characteristics like high lumen output, good color rendering index, high thermal stability and magnificent quantum efficiency involved with its unique optical behaviour. Due to the enhanced properties these nanomaterials are widely explored in the display devices like plasma display panels (PDP), field emission displays and light emitting diodes. Among the various RE3+ ions, Er3+
doped nanophosphors are widely explored on being the essential green component of the phosphor converted white LEDs because of green emitting luminescent properties. In this series, erbium activated oxide host matrix BaY2ZnO5 have found potential applications for luminescent phosphors on grounds of its magnificent electronic and magnetic properties, greater crystallinity. In present work, we are demonstrating the synthesis, properties and suitability of BaY2(1-x)Er2x
ZnO5 nanophosphors for the solid state lighting system in NUV excited PC-WLEDs. Erbium doped BaY2ZnO5 nanophosphor was successfully synthesized via sol-gel approach in nano dimension with particle size in 60-80 nm range as confirmed by transmission electron microscopy (TEM). The crystallinity of pure phased nanophosphor in orthorhombic lattice with Pbnm (62) space group was confirmed through X-ray diffraction analysis. On excitation at 380 nm (4I15/2→ 4G11/2 transition) the nanophosphor yields green emission at 549 nm attributed to 4S3/2→ 4I15/2 transition with optimum concentration for maximum luminescence was 4 mol%.
Dissolution and Shape Controlling of Crystalline ZnO
Authors: Chung Ji Yong , Yu Taekyung 
Published: February 2020

ZnO is a one of most promissing material that has many attractive chemical and physical properties. ZnO is direct-bendgap semiconductor with a large bandgap of 3.37 eV, also it has strong exciton binding energy and it usually has high electron mobility.
For this reason, It had widely used to light-emitting diodes, solar cells and sensors. Nowaday, demand of high performance device is much stronger, so many researcher enhance these properties to nanotructure as a necessity.
we introduce new way to control shape of ZnO in nanoscale.
Raman Mapping and Delineation of III-V Semiconductor Band Bending Characteristics
Authors: Lichterman Michael Frankston , Carim Azhar I , Brunschwig Bruce S , Lewis Nathan S 
Published: February 2020

Raman spectroscopy has previously been used to ascertain the nature and extent of band bending at III-V semiconductor interfaces. Many previous investigations have focused on samples cleaved in vacuum and subsequently exposed to oxygen gas or a thin metal deposition; generally, specific polarizations of incident and scattered light are applied and collected in order to specify and isolate the desired phonon peaks under investigation1,2. We demonstrate herein a more general and easily applied method to investigate III-V interfaces by Raman spectroscopy using analysis of the longitudinal optical (LO) and transverse optical (TO) phonons; furthermore, we provide a means by which the ratios resulting from such experimentation may be normalized. Interfaces can be deeply buried under tens or hundreds of nm of material and still be investigated, unlike the case with photoelectron spectroscopy; furthermore, this technique can provide electronic mapping of such interfaces with micron sensitivity.

References

1. Geurts, J., Analysis of band bending at III–V semiconductor interfaces by Raman spectroscopy. Surf. Sci. Rep.
1993,
18(1–3), 1-89.
2. Srnanek, R. et al. Study of δ-doped GaAs layers by micro-Raman spectroscopy on bevelled samples. App. Surf. Sci. 2004, 230, 379-385.
Photoluminescence Properties of Pr3+-Activated Ca-Based Perovskites Prepared By Amorphous Complex Method Using Aqueous Metal Complex Solutions
Authors: Sato Yasushi , Ohashi Yuta , Iguchi Yuta , Watanabe Tomohiro , Sugino Ayami , Kakihana Masato 
Published: February 2020

Ca-based perovskite phosphors activated by rare-earth ions have attracted considerable attention recently as prospective materials for various optoelectronic applications. Crystal structure of Ca-based perovskites is highly distorted from the ideal cubic perovskites as SrTiO3. Thus, strong ff-emissions of rare-earth ions should be derived from low site-symmetry of Ca site. In addition, photoluminescence properties of these phosphors are dependent on not only crystal structure of the host materials, but also preparation condition of the samples. Conventional solid-state reaction (SSR) method is not fit for the synthesis of phosphors with complicated compositions because the degree of cation mixing is relatively low due to slow interdiffusion of the cations. In this study, we investigated the preparation of Pr3+-activated Ca-based perovskite phosphors via an aqueous-solution process using metal complex solutions in order to improve the photoluminescence properties of these phosphors. Pr3+-activated CaTiO3 and CaSnO3 phosphors were prepared by amorphous metal complex (AMC) method using stable water-soluble Ti4+ and Sn4+ complexes coordinated to lactic acid. Especially, we developed a new stable water-soluble Sn4+ complex synthesized from SnCl4·nH2O. Photoluminescence properties of Pr3+-activated CaTiO3 and CaSnO3 under UV irradiation were significantly sensitive for the small deviation of the cation ratios of Ti/Ca and Sn/Ca. When the cation ratios in both the phosphors were less than 1.00, ff-emissions from the phosphors prepared by AMC method were low, compared with the phosphors prepared by SSR method. In contrast, when the cation ratios were precisely controlled from 1.00 to 1.05, ff-emissions of the phosphors prepared by AMC method were higher than those prepared by SSR method. Especially, Pr3+-activated CaSnO3 prepared by AMC method at the optimum condition showed high emission intensity under UV irradiation that was 1.9 times higher than those by SSR method (Fig .1). This work was partially supported by Grant-in-Aid for Scientific Research (C) (no. 15K06445) from MEXT, Japan. This work was also partially supported by the cooperative research program of the “Network Joint Research Center for Materials and Devices”.

Figure 1
(Invited) Development of High Temperature Materials and Technologies for Electrochemical Storage and Conversion
Authors: Soloveichik Grigorii L. 
Published: February 2020

The Advanced Research Projects Agency (ARPA-E) funds high risk, high reward transformational research to reduce energy related emissions, reduce imports of energy from foreign sources, improve energy efficiency across all economic sectors, and ensure US technological lead in advanced energy technologies, including electrochemical energy storage and transformation for grid scale and automotive applications.
High temperature electrochemical technologies and supporting materials (membranes, current collectors, seals, etc.) play an important role in electrochemical (batteries with molten electrodes and molten salt electrolytes) and chemical (electrosynthesis of fuels) energy storage and energy conversion (intermediate and high temperature solid oxide and proton conducting fuel cells and electrolyzers). In addition, high temperature electrochemical technologies to process and recycle metals such as aluminum, titanium, and magnesium are important for advanced manufacturing. The use of high temperatures allows for utilization of ion conducting materials, electrolytes and electrocatalysts, which cannot be utilized at ambient conditions due to low conductivity or activity respectively. Current challenges in high temperature electrochemistry are increasing ionic conductivity of liquid and solid electrolytes to decrease working temperatures and expand material compatibility, improving activity and selectivity of electrocatalysts to decrease energy consumption and costs, increasing power density of stacks to decrease the capital costs, and optimizing the balance of system, which is extremely important for smaller scale devices.
ARPA-E funded and currently funds multiple projects targeting high temperature electrochemical processes and development of materials compatible with these processes through OPEN, IDEAS and focused programs. The Modern Electro/Thermochemical Advances in Light Metals Systems (METALS) targets technologies that may provide inexpensive light metal materials for lightweight vehicles and aircraft. The Reliable Electricity Based on Electrochemical Systems (REBELS) program is focused at intermediate temperature fuel cells that operate between 200-500oC and includes cell capable to produce liquid fuels along with electricity to support the distributed energy generation for more reliable and flexible smart grid. The Renewable Electricity to Fuels through Utilization of Energy-dense Liquids (REFUEL) program seeks to fund the development of intermediate and high temperature electrosynthesis and fuel cells technologies to produce and utilize carbon-neutral fuels. This presentation will also highlight high temperature battery technologies using molten metal anodes funded by ARPA-E.
Alternative Ion-Exhange Materials for Membrane Capacitive Deionization
Authors: Palakkal Varada Menon , Arges Christopher George 
Published: February 2020

Membrane capacitive deionization (MCDI) is an energy efficient, cost effective desalination technique for brackish water to produce water for drinking and processes found in semiconductor and pharmaceutical manufacturing, energy production, and other water related industries.[1-3] The operating principle in MCDI is a potential induced electro-sorption of salt ions that migrate across the ion-exchange membrane layers to the porous carbon electrodes. Hence, the application of electric work reduces the salt content from the feed water. Saturation of the carbon electrodes then leads to discharge of the salt from the carbon electrodes, leading to recovered energy and an increase in salt concentration of the emanating flow stream from the MCDI cell. The discharge process regenerates the electrodes so salt removal can take place again. From a materials aspect of MCDI, most research has focused on carbon-based electrodes with the aim to improve device performance.[4-6] Conversely, little innovation has been made in alternative ion-exchange membrane materials for MCDI. Most reports of MCDI leverage commercially available membranes for electrodialysis.[1,3,7]
In this work, MCDI performance was correlated to ion-exchange membrane thickness. The experimental design evaluated examined:
i.) commercially available ion-exchange membranes, ii.) ion-exchange layered electrodes of different thicknesses with electrode samples being prepared by drop casting followed by spray painting of ionomer layer on top of the electrode; and iii.) drop casting a mixture of electron conducting carbon with dissolved ionomer. A home-built, single-cell MCDI module was characterized with the different ion-exchange materials using a 275 ppm salt feed. MCDI performance was determined by quantifying salt removal and energy efficiency and the individual resistance contributions in the system through electrochemical impedance spectroscopy.
References:
1 Biesheuvel, P. M. & van der Wal, A. Membrane capacitive deionization. Journal of Membrane Science 346, 256-262 (2010).
2 Lee, J.-H. & Choi, J.-H. The production of ultrapure water by membrane capacitive deionization (MCDI) technology. Journal of Membrane Science 409-410, 251-256 (2012).
3 Dlugolecki, P. & van der Wal, A. Energy Recovery in Membrane Capacitive Deionization. Environmental Science & Technology 47, 4904-4910 (2013).
4 Sharma, K. et al. Transport of Ions in Mesoporous Carbon Electrodes during Capacitive Deionization of High-Salinity Solutions. Langmuir 31, 1038-1047 (2015).
5 Xu, X. et al. Facile synthesis of novel graphene sponge for high performance capacitive deionization. Scientific reports 5, 8458 (2015).
6 Jia, B. & Zhang, W. Preparation and Application of Electrodes in Capacitive Deionization (CDI): a State-of-Art Review. Nanoscale Research Letters 11, 1-25 (2016).
7 Zhao, R., Biesheuvel, P. M. & van der Wal, A. Energy consumption and constant current operation in membrane capacitive deionization. Energy & Environmental Science 5, 9520-9527 (2012).

Figure 1
Meso-Scale Model of Li2O2 Formation in Li-O2 Batteries: Compactness of Thin Film and Its Link to Charge Transport Mechanism
Authors: Yin Yinghui , Zhao Ruijie , Deng Yue , Franco Alejandro A. 
Published: February 2020

Owing to its high theoretical capacity, Li-O2 batteries have attracted much attention during the past decades. However, in the state-of-art, the discharge capacity of a Li-O2 cell is far behind the theoretical value. The insulating nature of the discharge product Li2O2 can be one of the main issues and the maximum distance for electron tunneling through this thin film is less than 10 nm according to first-principle calculation.1 Nevertheless, the experimental finding of 40 nm Li2O2 film by Yang et al. breaks the limitation electron tunneling, which may imply that there may be other factors accounting for the thick Li2O2 film.2

In the present work, we simulated the growth of Li2O2 thin film during the discharge process of a Li-O2 battery and studied the influences of catalyst and LiO2 diffusion rate with a meso-scale model. On the basis of kinetic Monte Carlo method, this model combined a stochastic description of mass transport and a detailed elementary reaction We found that : (1) the interplay between diffusion kinetics and reaction kinetics influenced strongly the ordering of the Li2O2 thin film. With the presence of catalyst, the formed Li2O2 showed a lower degree of ordering and is more likely to be amorphous owning to the fast kinetics; (2) the mobility of LiO2 ion pair, which depends largely on the nature of the electrolyte, also has impacts on the homogeneity of the compactness of Li2O2 thin film. These results are of high importance to develop a better understanding on the role of catalyst and reaction kinetics in the Li-O2batteries.
References
[1] Viswanathan, V.; Thygesen, K. S.; Hummelshøj, J. S.; Nørskov, J. K.; Girishkumar, G.; McCloskey, B. D.; Luntz, A. C. J. Chem. Phys.
2011, 135 (21), 214704.
[2] Yang, C.; Wong, R. A.; Hong, M.; Yamanaka, K.; Ohta, T.; Byon, H. R. Nano Lett.
2016, 16 (5), 2969–2974.
[3] Blanquer, G.; Yin, Y.; Quiroga, M. A.; Franco, A. A. J. Electrochem.
Soc.
2016, 163(3), A329–A337.
[4] Yin, Y,; Zhao, R.; Deng. Y and Franco, A. A. J. Phys. Chem.Lett. (Submitted)
Magnesium Ethylenediamine Borohydride As Solid-State Electrolyte for Magnesium Batteries
Authors: Roedern Elsa , Kühnel Ruben-Simon , Remhof Arndt , Battaglia Corsin 
Published: February 2020

Efficient magnesium electrolytes are crucial in order to realize rechargeable magnesium batteries, which are an important contender for post-lithium-ion-battery technology.1,2 Due to the divalent positive charge carried by the Mg2+ ion, magnesium mobility is difficult to achieve and so far Mg ion conductivity in inorganic solids has only been reported for few systems and typically, conductivities above 10-5 Scm-1
are only reached above 400 °C, see Figure 1.
In this work, we demonstrate that partially chelated ethylenediamine magnesium borohydride complexes show promise as solid-state Mg conductors with unprecedented high conductivity of up to 6x10-5 Scm-1already at 70 °C. The compounds are easily prepared by a mechanochemical reaction and allow for reversible Mg plating/stripping at 60 °C, which is recognized to be a major challenge in magnesium ion batteries.
While the electrochemical stability, limited by the ethylenediamine ligand, must be improved to reach competitive energy densities, our results demonstrate that partially chelated Mg2+complexes represent a promising platform for the development of an all-solid-state magnesium battery.
References
1 D. Aurbach, G. S. Suresh, E. Levi, A. Mitelman, O. Mizrahi, O. Chusid and M. Brunelli, Adv. Mater., 2007, 19, 4260–4267.
2 H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour and D. Aurbach, Energy Environ. Sci., 2013, 6, 2265.
3 S. Ikeda, M. Takahashi, J. Ishikawa and K. Ito, Solid State Ionics, 1987, 23, 125–129.
4 N. Imanaka, Y. Okazaki and G. Adachi, J. Mater. Chem., 2000, 10, 1431–1435.
5 N. Imanaka, Y. Okazaki and G. Adachi, Ionics, 2001, 7, 440–446.
6 S. Higashi, K. Miwa, M. Aoki and K. Takechi, Chem. Commun., 2014, 50, 1320–2.

Figure 1
Unraveling the Potassium Ion Storage Mechanism in Graphite Foam
Authors: Liu Ji Lei 
Published: February 2020

The growing demands for electric automotive and regenerative energy storage applications, and the increasing caring for climate change and pollution, drive the search for high-performance electrochemical power sources that are also safe to operate, economically viable and environmentally friendly. Compared to LIBs and NIBs, very little is known about the electrochemical storage mechanism of KIBs. Here in operando studies including in-situ Raman and in-situ XRD characterizations, ex-situ XPS analysis and ab initio calculations are carried out for correlating the real-time electrochemical K+ intercalation process with structure/component evolution. Our results reveal three distinct intercalation stages are involved for K+ storage in few-layered graphene, corresponding to the formation of different GIC stages (e.g., KC36, KC24 and KC8). The K+ diffusion coefficients are found to be GIC stage dependent based on GITT and EIS results, corroborating the diversity in K+ intercalation pathways. The establishment of clear property-structure relations in this work promotes better understanding of the K+ storage mechanism in graphite and opens up a new exciting direction for designing new materials for K-ion Batteries.
Strain Engineering to Control the Electrochemistry of Battery Electrodes
Authors: Muralidharan Nitin , Brock Casey , Walker Greg , Pint Cary L. 
Published: February 2020

Strain engineering has transformed applications in the semiconductor electronics industry, but has not been widely explored as a tool for electrochemical applications. Our early studies have demonstrated for the first time that mechanical strain applied across interfaces of engineered 2-D nanomaterials or externally applied to pseudocapacitive electrodes can result in deviations in the energetics and kinetics of Faradaic charge storage reactions [1-2]. Here, we present results that extend this idea to vanadium pentoxide (V2O5) due to its well-known capability to function as a cathode for the intercalation of lithium ions. To characterize the role of strain in modulating the lithium insertion properties, we use atomic layer deposition (ALD) to prepare ultrathin coatings of crystalline V2O5 on the surface of superelastic NiTi shape memory alloy surfaces. As a key challenge in characterizing the role of strain is the ability to assess electrochemical properties in a fixed strain state, we exploit the capability of NiTi to "lock-in" strain in the elastic regime, which extends up to ~ 15% strain. This enables us to directly measure the average strain transferred to the V2O5 material, and correlate this to the observed electrochemical properties. Through electrochemical tests, we observe over 50 mV shift in the electrochemical potential that is correlated to strain, and over 2X change in the diffusion coefficient of lithium ions. We further build a semi-quantitative model for strain modulated battery performance that is supported by density functional theory calculations. Overall, this work demonstrates new degrees of freedom to design or engineer electrodes for energy storage by using pre-strained or strain-engineered electrode materials.
References:
[1]. N. Muralidharan, R. Carter, L. Oakes, A.P. Cohn, and C.L. Pint*, "Strain engineering to modify the electrochemistry of energy storage electrodes," Sci. Rep. 6, 27542 (2016).
[2]. L. Oakes, R. Carter, T. Hanken, A.P. Cohn, K. Share, B. Schmidt, and C.L. Pint*, "Interface strain in vertically stacked two-dimensional heterostructured carbon-MoS2 nanosheets controls electrochemical reactivity," Nat. Commun. 7, 11796 (2016).