bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electropolymerization of Poly(phenylene oxide) Films with Variable Thickness
Authors: Timmermans Marina , Deheryan Stella , Mattelaer Felix , Detavernier Christophe , Vereecken Philippe M. 
Published: February 2020

Electrochemical polymerization is a useful method for polymer coating formation that allows room temperature processing, selectivity in electrode modification and conformal deposition on high aspect ratio structures. This work is focused on the electropolymerization of phenol to prepare pinhole free poly(phenylene oxide) (PPO) films. PPO films have been shown promising for various applications including protective coatings of the battery electrode from electrochemical dissolution [1], blocking layers for reducing the leakage current in supercapacitors [2] or gate dielectric in field effect transistors [3]. Our interest in this study is to examine the electrodeposition of PPO on various conductive surfaces by cyclic voltammetry leading to its rapid passivation. We show that a thin PPO film that conformally coats porous MnO2 electrode can act as a lithium ion conductor with electronically insulating properties, interesting for battery applications. The thickness of the PPO film was altered by controlling the potential applied between the working and reference electrodes of an electrochemical cell (see Figure). Electronically insulating PPO films with the thickness of 10-50 nm were deposited on TiN substrates. Thermal stability of the PPO films of various thickness was investigated in various environments by in-situ spectroscopic ellipsometry in the temperature range of 0-400oC. The ellipsometric results of the PPO thickness lay in the same range as the AFM measurements. It was found that thicker films withstand the annealing temperature up to 250oC prior to the onset of the PPO thickness decrease. This insight is important for the optimization of the PPO anneal conditions in order to remove the residual solvent and potentially improve the polymer chains stacking.
[1] Rhodes C.P., et al, J. Non-Cryst. Solids, 350 (2004)
[2] Tevi T., et al., J. Power Sources, 241 (2013)
[3] Lipatov A., et al., Chem. Mater., 27 (2015)

Figure 1
Removal of Cyanide in Solution Using Electrodeionization
Authors: Tian Yun , Yang Yang , Fan Zheng , Wu Xingxing , Wu Zucheng 
Published: February 2020

Toxic and harmful gases such as HCN are emitted during the polyacrylonitrile-based carbon fiber production process. Electrodeionization(EDI) was applied to remove the CN-in the solution which obtained after the absorption by NaOH from the waste gas stream, meanwhile regenerate NaOH solution back to the absorption process.
A modified three-chambers EDI device was applied. There were three chambers from the cathode to the anode in proper order: negative electrode chamber 1 which was fed in the CN- solution from the bottom to the top, resin chamber 2 filled up with anion exchange resin, and the positive electrode chamber 3 flowing NaCl solution. There were anion-exchange membranes dividing the chambers between the chambers. CN- in chamber1 transferred into the resin chamber, and part of OH- produced by ionization under the DC power would regenerate the resin and make the CN- going through into chamber 3 continuously. Also, Cl2 was produced on the anode electrode in chamber 3 by electrolytic action which would oxidize the CN- to harmless substance. And, the main OH- stayed in chamber 1 so thatNaOH was regenerated. Effects of the configurations like the sizes, and operation conditions such as the current density and the flow rate were investigated to examine the feasibility of device. With the optimization of operation conditions, the effluent water of chamber 3 can reach below 0.5mg/L which meets the requirement of cyanide discharge standard.
Synthesis of Noble Metal Nanoparticles By Atomic Layer Deposition Utilizing Self-Assembled Monolayers Templates
Authors: Zhu Qianqian , Cao Kun , Shan Bin , Chen Rong 
Published: February 2020

Self-assembled monolayers (SAMs) are widely used as surface modification structures for thin films synthesis and designed nanostructures fabrication1. Alkyltrichlorosilanes is a group of SAMs widely applied in the field of area-selective atomic layer deposition (AS-ALD). The closely packed octadecyltrichlorosilane (ODTS) SAMs could act as monolayer resist to prohibit ALD2, while the pinholes on unsaturated ODTS SAMs could act as nucleation sites to initiate ALD growth. Thus the distribution and structure of pinholes, including its size and density, are important factors for utilizing SAMs template to fabricate nanoparticles via ALD. Many studies characterize SAMs and pinholes by atomic force microscopy (AFM), scanning electron microscopy (SEM), scanning tunneling microscope (STM), etc3. Most of these methods could provide the microscopic information on the pinhole structures, yet the information from these methods is quite localized and hard to obtain statistical average and full-scale information about the pinhole size and distribution density.
Here we report utilizing electrochemical impedance spectroscopy (EIS) to study the size distribution and loading of initial nanoparticles grown in those pinhole sites. EIS is a powerful and surface sensitive characterization technique to obtain the average and global characters of the detected surfaces4,5. In this study, the properties of unsaturated ODTS SAMs are characterized with EIS methods. The relationship between SAMs growth time and the pinholes properties has been established. With the SAMs immersing time increasing, the sizes and density distribution are both reduced. For SAMs sample immersed over long time, at least 24 hours, negligible pinholes are observed. Furthermore, Pd ALD process has been carried on those SAMs modified substrates. The distribution of Pd nanoparticles corresponds well with the pinholes. The results show that the nanoparticles grown on SAMs modified substrates depend on the pinholes properties. With SAMs modified substrate, ALD grown noble metal nanoparticles with uniform size and controlled loading density can be achieved.
References:

J. Christopher Love, Lara A. Estroff, Jennah K. Kriebel, Ralph G. Nuzzo, George M. Whitesides, Chem. Rev. 2005, 105, 1103−1169

Rong Chen, Hyoungsub Kim, Paul C. McIntyre, Stacey F. Bent, Chem. Mater. 2005, 17, 536-544

Han-Bo-Ram Lee, Marja N. Mullings, Xirong Jiang, Bruce M. Clemens, Stacey F. Bent Chem. Mater. 2012, 24, 4051–4059

Byung-Wook Park, Do-Young Yoon, Dong-Shik Kim, Journal of Electroanalytical Chemistry 2011, 661, 329–335

Xiaoquan Lu, Huiqing Yuan, Guofang Zuo, Jiandong Yang, Thin Solid Films 2008, 516, 6476–6482
Surface Chemistry of III-V Semiconductors After Wet Etching with HCl and H2O2
Authors: Mancheno-Posso Pablo , Muscat Anthony J. 
Published: February 2020

The introduction of III-V semiconductors in MOSFET technology has been hindered by the lack of good quality III-V oxides. These oxides are a source of surface states at the band edges or within the band gap that are a detriment to electronic performance. The removal of these oxides is typically accomplished by immersion in acid or basic aqueous solutions. The continuous etching of the substrate is achieved by adding an oxidizing agent. After etching, a smooth oxide-free surface is desired. HCl and H2O2 mixtures have been used for the etching of III-V materials.
In this work, we perform a comparative study of the etching of the (100) crystal plane of GaAs, InAs, InP, GaSb, and InSb. The selective etching of these materials was studied as a function of H2O2 concentration (0.0001-5 M) and at a fixed HCl concentration (0.01 M). The etching rate was determined by profilometry measurements made on wafers patterned with conventional photolithography. The chemical composition of the surfaces after etching was studied with X-ray photoelectron spectroscopy (XPS) and the final roughness was characterized with atomic force microscopy (AFM). The etching rate of GaAs and InAs (same group V atom) showed a volcano-shaped dependence on H2O2 concentration (0.01 to 1 M). A maximum etching rate was observed at 0.1 M with a value of 1.1±0.1 nm/s for GaAs and 0.9±0.3 nm/s for InAs. For 1 M H2O2, the etching rate decreased to 0.035±0.010 nm/s for GaAs and 0.26±0.13 nm/s for InAs. The etching rate of InP increased when the H2O2 concentration was changed from 0.01 to 0.1 M, and showed no significant increase for higher concentrations within the error of the measurements. The etching selectivity of GaAs to InP increased from about 55 at 0.01 M H2O2 to 137 at 0.1 M H2O2, and then decreased to 4 at 1 M H2O2. The etching rate of GaSb and InSb (same group V atom) increased linearly between 0.0001 and 0.001 M H2O2, but dropped significantly at higher concentrations. These substrates were visibly oxidized at high H2O2 concentrations and HCl etching was unable to keep up with the rate of oxidation. Substrates with the same group V atom exhibited similar etching trends in the range of H2O2 and HCl concentrations studied. This suggests that the removal of the group V atom is the rate limiting step in the etching of these materials. Temperature programmed desorption (TPD) of a GaAs sample after immersion in HCl showed that the surface was terminated by As-Cl bonds. These results along with the chemical composition of the samples after etching will be used to propose reaction mechanisms of III-V semiconductors in HCl and H2O2 mixtures.
(Invited) Characterization of Individual Si/SiO2 Interface Traps: Direct Observation of Single P
b0 Centers by the Charge Pumping (CP) Method and Correction of the Conventional CP Theory
Authors: Tsuchiya Toshiaki 
Published: February 2020

It is considered that interface traps will cause various reliability and variability problems in future nanoscale MOS devices, such as fluctuations in threshold voltage due to the variation in the number of interface traps involved, and the random position of the traps. Therefore, characterization of individual traps will be considered to become increasingly important.
Charge pumping (CP) technique is known to be a highly-precise method for evaluating the density of interface traps, therefore, the method has been widely used for the last 30 years. The CP current I
CP can be simply described by I
CP=fqN, where f is the gate pulse frequency, q is the electron charge, N is the total number of traps contributing to the CP current. Therefore, the conventional belief is that the density of interface traps N
it can be derived from N
it=I
CP/(fqA
G), where A
G is gate area of MOSFETs, and the CP current per trap should be fq. Actually, observation of single interface traps has been demonstrated by the CP method.
We made systematic measurements of CP current from single Si/SiO2 interface traps, and successfully observed for the first time that their current range is 0<I
CP≤2fq, but not a fixed value of fq. In order to judge if CP characteristics are due to single interface traps, we need to separate the CP characteristics into components from individual traps. For this purpose, we utilized some effective procedures, i.e., observation of the differences in threshold voltage in the local area where each trap is located, the dependences of CP characteristics upon on-time and off-time of the gate pulse. From the on-time and off-time dependences, we can observe electron capture processes and electron emission (i.e., hole capture) processes in individual traps, respectively.
Using these procedures, we confirmed if CP characteristics are due to single interface traps. We measured seventy samples, and among them, twenty-seven samples showed single trap properties. Thus, we concluded that CP current from single Si/SiO2 interface traps is indeed in the range of 0<I
CP≤2fq, but not a fixed value of fq, and the conventional CP theory is basically wrong. Moreover, using the procedures, we demonstrated fundamental trap-counting by the CP method. The current range 0<I
CP≤2fq can be expected from the nature of the P
b0 centers, therefore, the obtained results mean that we succeeded to directly and electrically observe single P
b0 centers, for the first time.
A Modified Electrolyte for a Rechargeable Manganese-Zinc Alkaline Cell
Authors: Hertzberg Benjamin Joseph , Steingart Daniel A , Chamoun Mylad , Hsieh Andrew , Davies Greg , Huang An , Meng Shirley 
Published: February 2020

There is a need for reliable, low-cost energy storage for electric vehicle applications. While advanced Li-ion batteries may possess sufficient power and energy density to be useful for electric vehicles, their high manufacturing and materials costs make them unsuitable outside of a relatively small market niche. Alkaline batteries, one of the most common modern forms of primary battery, are potentially ideal for electric vehicles. These cells depend on a reaction between zinc (Zn) and manganese dioxide (MnO2) to generate energy. This reaction gives alkaline batteries a relatively high energy density and a low cost per kilowatt-hour, but phase transformations occurring during deep discharge, particularly the formation of the electrochemically inactive ZnMn2O4 phase, prevent recharge. In a typical alkaline battery, useful rechargeability with minimal capacity losses can only be achieved if no more than 10% of the cathode’s capacity is used. [1]
We have developed a new, low-cost electrolyte which prevents the formation of electrochemically inactive phases, even during deep discharge. A capacity of 360 mAh/g on a cathode basis has been achieved cycling against zinc for more than 60 stable cycles, without evidence of ZnMn2O4 formation. We have also characterized the effects of this electrolyte as well as more conventional alkaline battery electrolytes using both conventional and in-operando synchrotron XRD techniques. We will discuss the impact of electrolyte formulation, charging and discharging protocols, and conductive additives on the performance of the system, and hypothesize on the mechanism by which this electrolyte prevents formation of electrochemically inactive phases.
References:
1. Shen, Yuwei, and Karl Kordesch. "The mechanism of capacity fade of rechargeable alkaline manganese dioxide zinc cells." Journal of power sources 87.1 (2000): 162-166
Amorphous Iron Phosphate : Potential Host for Various Charge Carrier Ions
Authors: Kim Sungjin , Gim Jihyeon , Song Jinju , Baboo Joseph Paul , Alfaruqi Muhammad Hilmy , Jo Jeonggeun , Kim Dongyun , Kim Yeoeun , Kim Jaekook 
Published: February 2020

Since 1990, the global demand for electricity has increased twice as much as the demand for energy overall, and the demand for electricity is expected to further increase by more than two-thirds over the next 20 years. Energy storage/conversion technologies have therefore become a crucial research topic as we seek to make society sustainable. In particular, electrical energy storage is critical not only for supporting electronic, vehicular and load-leveling applications but also for efficiently commercializing renewable solar and wind power. In response to the ever-increasing global demand for viable energy-storage systems, sodium and potassium batteries appear to be promising alternatives to lithium ion batteries because of the abundance, low cost and environmental benignity of sodium/potassium. Electrical energy storage via ion-intercalation reactions in crystalline electrodes is critically dependent on the sizes of the guest ions. Herein, we report on the use of a porous amorphous iron phosphate synthesized using ambient temperature strategies as a potential host that stores electrical energy through the feasible insertion of mono-/di-/tri-valent ions. A combination of ex situ studies reveals the existence of a reversible amorphous-to-crystalline transition in this versatile electrode during electrochemical reactions with monovalent sodium, potassium and lithium. This reconstitutive reaction contributes to realizing specific capacities of 179 and 156 mAh/g versus sodium and potassium at current densities of 10 and 5 mA/g, respectively. This finding facilitates the feasible development of several amorphous electrodes with similar phase behavior for energy-storage applications.

Figure 1
High Performance TiP2O7 Based Intercalation Negative Electrode for Aqueous Lithium-Ion Batteries Via a Facile Synthetic Route
Authors: Whitacre Jay , Wu Wei , Shanbhag Sneha , Chang Jiang , Rutt Ann 
Published: February 2020

Combining high energy mechanical alloying with intimate carbon coating has proven effective in improving electrochemical performance of polyanion-based materials (1, 2). Ball milling with intimate carbon helps to prepare a homogenous mixture of precursors and reduce particle size during following thermal treatment (3, 4). In addition, this combination can decrease the thermal treatment time needed (5). In this study, we demonstrated TiP2O7/graphite prepared by high energy mechanical alloying combined with intimate carbon coating has superior cycling performance in aqueous lithium-ion electrolyte.
The TiP2O7/graphite composite material was prepared by an intensive mechanical mixing solid state synthesis method at 700°C. Physical properties were characterized via powder X-ray diffraction, Rietveld refinement, SEM, BET and TGA. Electrochemical performance was evaluated in both a three electrode test setup and two electrode coin cells via cyclic voltammetry and galvanostatic cycling tests. The TiP2O7/Graphite composite demonstrates excellent cycling performance in 1M Li2SO4 when matched with LiMn2O4 as a positive electrode: when cycled at C/2 for 150 cycles, the capacity retention is over 91% with coulombic efficiencies exceeding 99%. The initial discharge capacity obtained at a C/10 rate is 91mAh/g which was about 75% of theoretical capacity 121mAh/g.

Reference:

1. W. Wu, A. Mohamed and J. F. Whitacre, Journal of The Electrochemical Society, 160, A497 (2013).
2. W. Wu, J. Yan, A. Wise, A. Rutt and J. F. Whitacre, Journal of The Electrochemical Society, 161, A561 (2014).
3. J.-K. Kim, G. Cheruvally, J.-W. Choi, J.-U. Kim, J.-H. Ahn, G.-B. Cho, K.-W. Kim and H.-J. Ahn, Journal of Power Sources, 166, 211 (2007).
4. J.-K. Kim, J.-W. Choi, G. Cheruvally, J.-U. Kim, J.-H. Ahn, G.-B. Cho, K.-W. Kim and H.-J. Ahn, Materials Letters, 61, 3822 (2007).
5. L.-X. Yuan, Z.-H. Wang, W.-X. Zhang, X.-L. Hu, J.-T. Chen, Y.-H. Huang and J. B. Goodenough, Energy & Environmental Science, 4, 269 (2011).

Figure 1
Effect of Pth-Coated Li Powder Anode in Lithium Metal Batteries System
Authors: Lee Jae Won , Hwang Sun Woo , Yoon Woo Young 
Published: February 2020

The Li metal anode is one of interested electrode which applied on the post-LIB (Li ion battery) system. However the dendrite growth on the Li surface made hard to commercialized Li metal anode battery. In this reason, we fabricated Li powder by Droplet Emulsion Technique (DET) and coated polythiophene (Pth) on the Li powder by polymerization method.[1] The thiophene monomer and FeCl3 was stirred in CHCl3 solution and polymerized by in situ on the surface of lithium powder.[2] This experiment formatted uniformly PTh layer on the Li powder surface. This Pth layer was helpful to suppressed the lithium dendrite growth when Li ion deposited on the Li powder (charge process). To fabricate the electrode Pth-coated lithium powder was placed on the stainless steel (SUS) mesh (15 Φ) and pressed 20 kg cm-2 regularly. Also the LiV3O8 (LVO) was used as cathode electrode because it is non-lithiated material. The cell was assembled in the coin type cell (CR2032) in Dry room.
The morphology of lithium dendrite was observed by the FE-SEM, TEM and the coating layer was investigated by NMR and FT-IR. The conductivity of lithium powder anode and polythiophene-coated lithium powder was also measured by impedance analysis. All the cell were charged and discharged to 25% of the theoretical lithium capacity (965 mAhg-1) at 0.2 0.5, 1, 2 C-rate respectively. The result was analyzed EIS and CV.

[1] Shin-Kook Kong, Bok-Ki Kim, Woo-Young Yoon, J. Electrochem. Soc, 159 9) A1551-A1553 (2012)
[2] Haipeng Guo, Li Liu, Hong, Hong Shu, Xiukang Yang, Zhenhua Yang, Meng Zhou, Jinli Tan, Zichao Yan, Hai Hu, Xianyou Wang, J. Power Sources, 247 (2014) 117-126
Advanced Characterization of Materials Electronic Structure with High Energy-Resolution X-Ray Spectroscopy
Authors: Sokaras Dimosthenis , Weng Tsu-Chien , Nordlund Dennis 
Published: February 2020

High-resolution hard x-ray spectroscopies (XES, HERFD, RIXS, XRS) are well-established characterization tools for providing insights of material’s electronic and geometric structure. At SLAC National Accelerator Laboratory we have developed recently a set of high-resolution x-ray spectroscopic capabilities with oustanding throughput and efficiency. These developments have made feasible the routine study of the electronic structure and the ligand environment of metal coordination compounds and active centers in metalloproteins, electrochemical process under in-situ conditions, PV's, as well as studies on catalytic systems under ambient conditions.Representative examples of in-situ application in batteries, electrocatalysis, hydrogen storage, etc. will be presented and discussed from the ongoing spectroscopy programs of Stanford Synchrotron Radiation Lightsource.
Flexible Graphene Electrode-Based Organic Photovoltaics with Record-High Efficiency
Authors: Park Hyesung , Chang Sehoon , Zhou Xiang , Kong Jing , Palacios Tomas , Gradecak Silvija 
Published: February 2020

Flexible organic and hybrid organic-inorganic solar cells require both the flexible photoactive media and flexible electrodes with good conductivity and transparency. Graphene has been proposed as a promising flexible electrode due to its mechanical and chemical robustness, excellent electrical and optical properties, and potentially low-cost processing. We have designed graphene electrode-based flexible polymer solar cells with thieno[3,4-b]thiophene/benzodithiophene (PTB7) and [6,6]-phenyl C71-butyric acid methyl ester (PC71BM) by resolving the issues occurring at the interface between graphene and charge transporting semiconducting materials. We demonstrate highly efficient flexible devices with power conversion efficiencies of 6.1% (anode) and 7.1% (cathode) achieved via thermal treatment of molybdenum trioxide (MoO3) electron blocking layer, direct deposition of ZnO electron transporting layer on graphene. The advances in this work demonstrate graphene has great potential as a promising transparent electrode in a variety of flexible optoelectronic devices.