bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen Reduction Reaction Activity of Aerosol Jet Printed Layers of Graphite and Graphene
Authors: Farjami Elaheh , Rottmayer Michael , Deiner L. Jay 
Published: February 2020

Graphene and graphene-based materials have shown great promise in a broad range of applications including electrochemical sensors, supercapacitors, and lithium ion batteries. However, practical realization of the potential utility of graphene requires development of low cost, high volume methods of material synthesis and manufacturing-ready methods of device fabrication. This work aims to address the second challenge by demonstrating the use of aerosol jet printing for the fabrication of catalytically active electrodes.
Graphene and graphite were formulated into high concentration inks (10mg/mL). These inks were aerosol jet printed to create micron scale layers (2 – 10 microns). The catalytic activity of the aerosol jet printed electrodes was evaluated in oxygen saturated basic solution. It was found that the oxygen reduction reaction activity of the aerosol jet printed graphene electrode was ~ 5 times higher times than the activity of the same material when drop cast. Electrochemical impedance spectroscopy showed that the activity difference correlated with a large decrease in the charge transfer resistance of aerosol jet printed graphene as opposed to drop cast graphene. Further, the activity of the aerosol jet printed graphene electrode was ~ 3 times greater than the activity of the aerosol jet printed graphite. In contrast, the drop cast materials did not show a measurable difference in performance. These results indicate that aerosol jet printing is a viable way to deposit micron scale layers of graphene and related materials. In addition, the activity of the graphene electrode is strongly dependent on the deposition method, with aerosol jet deposited electrodes showing a strong performance improvement over their drop cast counterparts.
Invited Presentation: Probing Local Ionic Dynamics in Functional Oxides: From Nanometer to Atomic Scales
Authors: Kalinin Sergei V. 
Published: February 2020

Vacancy-mediated electrochemical reactions in oxides underpin multiple applications ranging from electroresistive non-volatile memory and neuromorphic logic devices memories, to chemical sensors and electrochemical gas pumps, to energy conversion systems such as fuel cells. Understanding the functionality in these systems requires probing reversible (oxygen reduction/evolution reaction) and irreversible (cathode degradation and activation, formation of conductive filaments) electrochemical processes. In this talk, I summarize recent advances in probing and controlling these transformations locally on nanometer level using scanning probe microscopy. The localized tip concentrates the electric field in the nanometer scale volume of material, inducing local transition. Measured simultaneously electromechanical response (piezoresponse) or current (conductive AFM) provides the information on the bias-induced changes in material. Here, I illustrate how these methods can be extended to study local electrochemical transformations, including vacancy dynamics in oxides such as titanates, La
x
Sr1-x
CoO3, and Y
x
Zr1-x
O2. The formation of electromechanical hysteresis loops and their bias-, temperature- and environment dependences provide insight into local electrochemical mechanisms and can be directly linked to the defect chemistry. In materials such as lanthanum-strontium cobaltite, mapping both reversible vacancy motion and vacancy ordering and static deformation is possible, and can be corroborated by post mortemSTEM/EELS studies. In ceria, a broad gamut of electrochemical behaviors is observed as a function of temperature and humidity. The possible strategies for elucidation of origins of ionic motion at the electroactive interfaces in oxides using high-resolution electron microscopy and combined ex-situ and in-situ STEM-SPM studies are discussed. In the second part of the talk, probing electrochemical phenomena on in-situ grown surfaces with atomic resolution is illustrated.
Research supported (SVK) by the U.S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division and partially performed at the Center for Nanophase Materials Sciences, a DOE-BES user facility.
Reversible Chemical and Electrochemical Dehydrogenation/Hydrogenation of Primary Alcohols Catalyzed By Iridium Complexes
Authors: Bonitatibus Peter , Doherty Mark , Rainka Matthew , Peters Andrea , Siclovan Oltea , Simone Davide , Soloveichik Grigorii 
Published: February 2020

Development of efficient electrocatalysts for both dehydrogenation and hydrogenation of organic fuels is critical to the realization of regenerative liquid fuel cells (RLFCs). Alcohols are convenient fuels currently utilized in direct alcohol fuel cells (DAFCs) and are capable of undergoing reversible partial dehydrogenation without CO2 emission in a RLFC.1 An Ir-diaminodiolefin complex, [Ir(trop2DACH)][OTf] (trop2DACH = N,N’-bis(5H-dibenzo[a,d]cyclohepten-5-yl)-1,2-diaminocyclohexane) (1) was proposed by Grützmacher et al.2 as a catalyst for alcohol oxidation with benzoquinone. Previously we demonstrated that 1 also catalyzes chemical dehydrogenation of 4-methoxybenzyl alcohol to p-anisaldehyde with one-electron oxidants in the presence of a base as well as electrochemical dehydrogenation at a low applied potential with high selectivity and Faradaic efficiency.3 In this presentation we report both chemical and electrochemical dehydrogenation of primary alcohols and hydrogenation of the corresponding aldehydes using 1 or an analogous iridium complex [Ir(trop2DAD)]OTf (trop2DAD = N,N’-bis(5H-dibenzo[a,d]cycloheptene-5-yl)-1,4-diazabuta-1,3-diene) (2) as a single homogeneous catalyst. In the chemical processes the same acid/conjugate base pair (substituted phenols/phenolates) is used with an appropriate one electron reductant (e.g. cobaltocene) for hydrogenation or oxidant (e.g. ferrocene) for dehydrogenation. In the electrochemical processes 1 and 2 catalyze dehydrogenation and hydrogenation with high faradaic efficiency and excellent selectivity though hydrogenation produced smaller yields. Further details on the effects of the base, solvent and electrolysis conditions on chemical and electrochemical catalysis will be provided.
This work is supported as part of the Center for Electrocatalysis, Transport Phenomena, and Materials (CETM) for Innovative Energy Storage, an Energy Frontier Research Center (EFRC) funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001055.
1. Kariya, N. F., Fukuoka, A.; Ichikawa, M., Phys. Chem. Chem. Phys. 2006, 8, 1724
2. Königsmann, M.; Donati, N.; Stein, D.; Schönberg, H.; Harmer, J.; Sreekanth, A.; Grützmacher, H., Angew. Chem. Int. Ed. 2007, 46, 3567.
3. Bonitatibus, P. J.; Rainka, M. P.; Peters, A. J.; Simone, D. L.; Doherty, M. D., Chem. Communs 2013, 49, 10581.
Porphyrin-Based Supramolecular Alternating Block Copolymer
Authors: Haino Takeharu 
Published: February 2020

S-shaped tetrakisporphyrin 1 forms supramolecular polymeric assemblies via a complementary affinity1,2 of its bisporphyrin units in solution.3 The self-association constant determined by applying the isodesmic model is more than 106 L mol–1, which suggests that a sizable polymer forms at millimolar concentrations at room temperature. Trinitrofluorenone (TNF) binds within the molecular clefts provided by the bisporphyrin units via a charge transfer interaction. Thus, bisTNF guest can connect the tetrakisporphyrin via host-guest interaction to form an alternating block copolymer. In this presentation, we will discuss the structure transition from the tetrakisporphyrin-based supramolecular homopolymer to an alternating AB type block copolymer through competitive ditopic guest complexation.
1) Haino, T. et al., Y. Tetrahedron Lett.
2005, 46, 257.
2) Haino, T. et al., Y. J. Org. Chem.
2006, 71, 2572.
3) Haino, T. et al., U. Proc. Natl. Acad. Sci. USA
2009, 106, 10477.
Flexible Nanocomposite Polymer Based Sensors for Breast Cancer Diagnostics
Authors: Khosla Ajit 
Published: February 2020

According to the data published by WHO, it is estimated that 226,870 women in United States will be diagnosed with breast cancer and 39,510 women will die of breast cancer in 2012. On average, 110 american women will die of breast cancer every day. Mammography, the current standard in screening breast cancer, is uncomfortable, requires specialized facilities and exposes the breast to a small but significant amount of radiation. It is known that exposing the breast to mammography radiation can lead to breast cancer later in life, and is not recommended for women below the age of 39. Over last decade, with hightened awareness, survival rate for women with breast cancer is increased dramatically when diagnosed at an early stage and has resulted an increase in survival rates.
In order to slove the isssues with mamography, we are developing an Electrical Impedance Tomography (EIT) system. We have developed a high density flexible sensor array on a silicone polymer sheets, to deliver small electrical impulses to the breast and measure the resistance of the underlying tissue. These measurements allow us to generate a 3-D map of the breast, with abnormalities indicated as areas of higher resistance/impedance. This radiation-less technique, termed Electrical Impedance Tomography (EIT), aims to solve the problems associated with mammography while enhancing early detection capabilities.
Impact of Thermal History on Grain Size and Grain Size Distribution of Thermally Cycled Cu-Tsvs
Authors: Marro James Brandon , Okoro Chukwudi A , Obeng Yaw S. , Richardson Kathleen A 
Published: February 2020

Through silicon vias (TSV) are copper (Cu) interconnects used in three dimensional integrated circuits (3D-IC) and other packaging to allow inter-chip communication. Since Cu is anisotropic, understanding the evolution of microstructure in TSVs is of major importance as it can influence the Cu’s electrical properties, such as resistance and electro-migration resistance, as well as mechanical properties. These properties can affect the materials response to thermo-mechanical stresses undergone by Cu-TSVs. Microstructural studies have focused on isothermal holding temperatures and times to imitate fabrication conditions [1-3], however, in-use conditions, which are typically of lower temperatures and higher frequencies to replicate thermal cycling over a chip’s lifetime, have not been greatly explored. This study correlates simulated in-use cycling parameters, such as cycling temperature and number of cycles, to microstructural changes, specifically grain size, observed in the Cu of TSVs. Silicon (Si) chips containing blind Cu-TSVs underwent 2000 thermal cycles from room temperature to maximum temperatures of 100 °C, 150 °C, or 200 °C. Grinding, polishing, and focus ion beam (FIB) milling were used to cross-section the TSVs and provide sufficient surface quality for electron backscattering diffraction (EBSD) to evaluate microstructural changes from thermal cycling. The average grain size remained around 3 μm and no significant differences were documented for average grain sizes along the length of TSVs before and after cycling. Furthermore grain size distribution also, showed little change with peaks around 1 μm for samples containing minimal voiding and approximately 2.5 μm for samples with significant pre-existing voids. While the low cycling temperatures used in this study are indicative of the conditions used in a majority of applications, they are too low to activate grain boundary migration and cause much microstructural changes in the Cu-TSVs.
References:
1. C. Okoro, R. Labie, K. Vanstreels, A. Franquet, M. Gonzalez, B. Vandevelde, E. Beyne, D. Vandepitte and B. Verlinden, Journal of Materials Science, 46 [11] 3868-3882 (2011).
2. A. Heryanto, W. N. Putra, A. Trigg, S. Gao, W. S. Kwon, F. X. Che, X. F. Ang, J. Wei, R. I Made, C. L. Gan and K. L. Pey, Journal of Electronic Materials, 41 [9] 2533-2542 (2012).
3. H. Shin, B. Kim, J. Kim, S. Hwang, A. Budiman, H. Son, K. Byun, N. Tamura, M. Kunz, D. Kim and Y. Joo, Journal of Electronic Materials, 41 [4] 712-719 (2012).
Development of 3-D Chemical Mechanical Polishing Process for Nanostructuring of Bioimplant Surfaces
Authors: Ozdemir Zeynep , Orhan Orcun , Bebek Ozkan , Basim G. Bahar 
Published: February 2020

This study focuses on the development of a three dimensional chemical mechanical polishing (CMP) process to induce smoothness or controlled nano-structures on the bio-implant material surfaces, particularly for an application on the dental implants. CMP helps produce implant surfaces that are cleaned from potentially contaminated surface layers by removing a nano-scale top layer during the process. Simultaneously, it creates a protective oxide film on the surface to limit any further contamination to minimize risk of infection [1]. Furthermore, the process can induce controlled surface topography. Therefore, we propose CMP as a synergistic method for nano-structuring of implant surfaces. In our earlier work, we have demonstrated that the CMP induced controlled surface roughness on the titanium based bio-materials helped control the infection resistance through formation of a self-protective titanium oxide film on the implant surfaces [2]. Yet, it is critical to be able to extent these findings to a 3-D platform to make the dental implants processed by CMP application.
The 3-D CMP process is established through use of robotics and control systems by integrating a robotic arm to the sample to be polished through a force-torque sensor. This technique, once programmed, can induce the same force on the various regions of the bio-implant sample and effectively smoothen or nano-structure the alternative surfaces on the implant. Considering the wide applications [3] of the implants as dental implants, orthopedic devices, cardiac pacemakers and catheters, this new application of CMP is believed to help create a new market for the process.
References:

Basim, G.B., Karagoz, A., Ozdemir, Z., “Characterization of Chemically Modified Thin Films for Optimization of Metal CMP Applications”. MRS Online Proceedings, 1560 (2013) DOI: 10.1557/opl.2013.876.

Basim, G.B., Ozdemir Z., Mutlu, Özal “Biomedical Applications of Chemical Mechanical Polishing" Proceedings of the International Conference on Planarization/CMP Technology, pp. 385, October 2012

Shirkhanzadeh, M., Azadegan, M., Liu, G. Q., Mater. Lett., 24 (1995) 7-12.
Effect of La Doping of Ceria Abrasives on STI CMP Selectivity
Authors: Bulusu Venkata Sesha Praveen , Park Jin-Goo , Ramanathan S 
Published: February 2020

Shallow trench isolation (STI) is used to isolate the transistors in an integrated chip and chemical mechanical planarization (CMP) is a key step in the STI integration scheme [1]. Ideally a high silicon dioxide removal rate and a low silicon nitride removal rate (i.e. high selectivity) is needed. High selectivity can be achieved when amino acids such as L-proline are used as additives along with ceria abrasives [2-3] but they do not work well with other abrasives [4]. Even when ceria is used as abrasive high selectivity is not observed in some cases [5].
In the present study, ceria is synthesized using sol gel and liquid phase synthesis (LPS). Polishing experiments are done on different ceria abrasives with same additives. To study the effect of impurity on polishing, lanthanum is added to ceria during the synthesis stage. The polishing results show that ceria without any impurity give high selectivity with L-proline while ceria with lanthanum as impurity does not give high selectivity.
To compare the results of polishing, commercial ceria with high and low purity obtained from sigma aldrich (ceria-SA) are considered for polishing experiments. Polishing with commercial ceria show similar results obtained with synthesized ceria. The ceria particles both commercial and synthesized were characterized by x-ray diffraction, energy dispersive spectra and scanning electron microscopy techniques. Polishing experiments were also conducted with milling the commercial ceria to evaluate if the size of ceria abrasive plays a role in modifying the selectivity.
References:
[1] J.M. Steigerwald, S.P. Murarka, R.J. Gutmann, Chemical Mechanical Planarization of Microelectronic Materials, John Wiley & Sons, New York, 1997.
[2] W.G. America, S.V. Babu, Electrochem. Solid-State Lett. 7 (2004) G327 – G330.
[3] R. Srinivasan, S.V. Babu, W.G. America, Y.-S. Her, US Patent 6,468,910 B1 (2002).
[4] R. Manivannan, S. Ramanathan, Microelectron. Eng. 85 (2008) 1748 - 1753.
[5] P.W. Carter, T.P. Johns, Electrochem. Solid-State Lett. 8 (2005) G218 – G221.
(Invited) Spatial ALD, Deposition of Al2O3 Films at Throughputs Exceeding 3000 Wafers per Hour
Authors: Granneman Ernst H.A. , Kuznetsov Vladimir I. , Vermont P. 
Published: February 2020

During the last few years various types of ALD films have successfully been introduced in high-volume manufacturing in a number of industries. Particularly in the semiconductor industry the implementation is wide spread (high-k gate stacks, capacitor dielectrics, diffusion barriers, etc.).
More recently a specific type of ALD film, Al2O3, was widely researched as a potential surface passivation layer for solar cell surfaces in the PV industry. Thin (< 10nm) Al2O3 films passivate p-type surfaces very effectively. On the one hand intrinsic negative charges in the dielectric film repel charge carriers, while on the other hand hydrogen that is present in the ALD films passivates dangling bonds at the Si/SiO2/ Al2O3 interface. The combination of both effects reduces the charge recombination losses considerably. The overall result is an increase in cell efficiency of 0.5-1% (absolute). Based on extensive testing of these films, it is to be expected that Implementation in PV manufacturing will take place in the near future.
There is a large difference in film and process requirements of ALD films applied in the semiconductor and PV industries. Whereas uniformity and defects (particles) are very important in the IC industry this is much less so in PV. Much more important in the PV industry are cost and throughput. Typical numbers for both industries are a Cost of Ownership of 2-10 vs. 0.02-0.05$/wafer, respectively, and 10-50 vs 1500-2500 wfrs/hr..
As ALD processes are notoriously slow, ways must be found to increase the throughputs considerably. This is done by either using batch furnaces loaded with 500-1000 wafers per batch, or in-line systems in which wafers are loaded, processed and unloaded in a continuous flow of 0.5-0.8 wafers/s.
The latter type of system is based on the so-called spatial ALD process. An example is shown in the figure. In this system (Levitrack) wafers are loaded in a track in which zones with precursors TMA and H2O are spatially separated by zones of inert gas. While floating on a gas cushion, the wafers pass ALD ‘cells’ with fixed sequences of TMA and water, adding a thin layer of Al2O3 with each passage through a cell. The advantages of this approach are several: high throughput, atmospheric processing, no deposition on the inside walls of the track, no moving parts such as valves, pumps, etc.
Typical results obtained with this system are: film uniformity 3-4%, life time of solar cell charge carriers > 3ms, efficiency enhancement 0.4-0.8%, CoO ~ 0.04$/wfr.
In the paper more details will be provided on the economy of this type of system, as well as on film characteristics and efficiency enhancements realized in a variety of solar cell structures.
Optochemical Self-Organisation of Functional Microstructures
Authors: Saravanamuttu Kalaichelvi , Hosein Ian Dean , Lin Hao , Ponte Matthew R , Basker Dinesh Kumar 
Published: February 2020

Our group previously reported an optochemical organization route to 3-D optical and microstructural lattices that combines the spontaneity of self-organisation to the precision and directionality of lithography. This method exploits the inherent instability of a broad, uniform beam of white light propagating in a photopolymer and its consequent division into identical filaments of light. By imposing spatially controlled noise on the light beam, the self-organizing filaments can be coaxed into 2-D and 3-D lattices. Unlike any other known self-organised or lithographically constructed structure, these lattices comprise functional, multimode and multi-wavelength cylindrical waveguides.
The objective of the work presented here is to apply multidirectional waveguide lattices (MWGLs) as wide-angled, light-capturing coatings that increase the intensity of light that is incident on optical devices including photovoltaic (PV) cells. Our approach is strongly motivated by the fact that even small increments of energy conversion efficiency (<1%) of PV modules are critical in the field. Furthermore, wide-angled, light-capture could eliminate (expensive) mechanised rotation of solar panels to track the Sun’s diurnal trajectory. We employ optochemical organization to prepare elastomer films comprising up to 5 intersecting arrays of waveguide lattices, which are oriented over a large range of angles with respect to the surface normal. When integrated into solar cell devices for example, the MWGLs could capture light seamlessly over a large range of angles and deliver intensity to the photovoltaic module and in this way, could increase conversion efficiencies.