bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boron Subphthalocyanines and the Exploration of Other p-Block Metal Phthalocyanines for Use in Organic Electronics
Authors: Bender Timothy P 
Published: February 2020

For some time our group has been focused on the design and synthesis of derivatives of boron subphthalocyanine (BsubPc) for application in organic electronics. In most cases, organic electronic devices utilize the prototypical BsubPc, chloro boron subphthalocyanine (Cl-BsubPc). We have shown that by using facile chemical transformations we can tailor the nature of the BsubPc to a dye, sublimate, engineered crystal or polymer. Early on in our research program we showed that peripheral functionalization of the BsubPc moiety had detrimental effects on the electrochemical behavior/stability. We therefore focused on chemical derivatization of the boron metal centre while maintaining the hydrogen periphery. The chemical transformations we have found most successful rely on the oxo-philicity of the boron metal centre.
In this presentation I will outline examples of each type of BsubPc, the chemistry we used to achieve each derivative, in addition to presenting their application in organic electronic devices including organic light emitting diodes (OLEDs) and organic photovoltaics (OPVs).
I will also highlight our group’s recent interest in expanding our methodology to other p-block metal phthalocyanines (M-Pcs) including Pcs of aluminum, silicon, germanium and phosphorous. In each case the metal was chosen due to its abundance and its ability to participate in our previously established oxo-philic based chemistry. Preliminary organic electronic device data will also be presented.
Coauthors will be cited as appropriate throughout the presentation.

Leading References:

(1) “Pentafluorophenoxy Boron Subphthalocyanine (F5BsubPc) as a Multifunctional Material for Organic Photovoltaics.” Morse, G.E.; et al. ACS Appl. Mat. Inter., 2014, 6 (3), 1515–1524.
(2) “Utilizing the π-Acidity of Boron Subphthalocyanine to Achieve Novel Solid-State Arrangements.” Paton, A.S.; et al. Crystal Growth & Des., 2013, 13 (12), 5368–5374.
(3) “Halogen bonds can direct the solid state arrangement of phenoxy-boron subphthalocyanines.” Virdo, J.D.; et al.CrystEngComm, 2013, 15, 3187-3199.

Figure 1
Iron(III) Protoporphyrin IX Associates with Proteins in a Sequence-Dependent Manner
Authors: Imhof Diana , Kühl Toni , Goradia Nishit , Brewitz Hans Henning , Wißbrock Amelie , Ohlenschläger Oliver 
Published: February 2020

The role and action of heme as a regulatory effector of proteins came more and more into the focus of biochemical research aiming at a complete understanding of this molecule’s function in the organism apart from its well-investigated embedment in hemoproteins, which e.g. are involved in gas transport, catalytic reactions or electron transfer [1-3]. Transient binding of regulatory heme to proteins might significantly change a protein's function. Distinct sequence stretches on the protein surface are responsible for interaction with heme. As a consequence of association, conformational changes within the protein may lead to changes in the protein's activity [4]. Interactions between heme and characteristic iron-coordinating amino acids (cysteine, histidine, tyrosine) are well-known. In addition, however, the surrounding amino acids contribute to the association of the protein with the protoporphyrin ring system. This fact was confirmed by results of a combinatorial peptide library screening [1]. Based on these data we predicted motifs for heme binding as well as proteins as possible targets, such as dipeptidyl peptidase 8 which subsequently was proven to be inhibited by heme [5]. Further targets possessing a great potential as heme-regulated proteins are currently under investigation. In-depth structural studies e.g. using UV-vis, resonance Raman, and NMR spectroscopy revealed the existence of different binding modes for heme-peptide/protein complexes [6]. These investigations resulted in the first structures of heme-peptide complexes known so far [5,7]. Binding data and structural characteristics displayed specific sequence requirements that, in turn, present suitable tools to identify potential heme-regulated proteins and, moreover, open new perspectives for diagnosis and treatment of pathophysiological conditions associated with non-balanced concentrations of bound and free regulatory heme in the organism [6].
References
1. Kühl, T., Sahoo, N., Nikolajski, M., Schlott, B., Heinemann, S.H., Imhof, D., Chembiochem
2011, 12, 2846-2855.
2. Yao, X., Balamurugan, P., Arvey, A., Leslie, C., Zhang, L., Biochem. Biophys. Res. Commun. 2010,403, 30-35.
3. Atamna, H., Boyle, K., Proc. Natl. Acad. Sci. USA
2006, 103, 3381-3386.
4. Shimizu, T., J. Inorg. Biochem.
2012, 108, 171-177.
5. Kühl, T., Wißbrock, A., Goradia, N., Sahoo, N., Galler, K., Neugebauer, U., Popp, J., Heinemann, S.H., Ohlenschläger, O., Imhof, D., ACS Chem.
Biol.
2013, 8, 1785-1793.
6. Kühl, T., Imhof, D., Chembiochem
2014, 15, 2024-2035.
7. Brewitz, H.H., Kühl, T., Goradia, N., Galler, K., Popp, J., Neugebauer, U., Ohlenschläger, O., Imhof, D., submitted.
Hydrogen-Bonding and Pi-Stacking Induced Self-Assembly of Picolinic Acid-Substituted Phthalocyanine Derivatives
Authors: Bottari Giovanni , Ballesteros Beatriz , Fernandez Collado Javier , Torres Tomas 
Published: February 2020

The preparation of organic-based, supramolecular architectures which present a high degree of order spanning from the nanoscopic to the macroscopic level across multiple length scales is highly desirable and represents a key issue within the fast-growing fields of nanoscience and nanotechnology.[1] In this context, self-assembly appears as an attractive and efficient strategy for the construction of such ordered structures as it can allow the preparation of complex, (multi)functional systems in an efficient and controlled way.[2] Among the organic compounds used for this purpose, π-conjugated systems such as phthalocyanines (Pcs),[3] aromatic macrocycles featuring unique structural, optical and redox properties,[4] are ideal candidates due to their excellent self-organization ability.[5]

We present here a new family of picolinic acid-terminated Pcs (1-3, Figure 1) which are able to self-aggregate in different solvents giving rise to the formation of columnar H-aggregates as a result of a combination of π-π supramolecular interactions between the Pc macrocycles and hydrogen bonding interactions between the terminal picolinic acid moieties.[6] Remarkably, the assembly/disassembly of these supramolecular systems can be reversible controlled by the addition of acids or bases to the Pc solutions. In Pc 3, chiral alkoxy units have been introduced at the Pc peripheral positions with the aim of influencing the stacking of the H-aggregates towards the formation of single-handed columnar structures.

References

1. Special issue on “Supramolecular approaches to organic electronics and nanotechnology”. Adv. Mater.
2006, 18, 1227-1329.
2. Special issue on “Supramolecular chemistry and self-assembly”. Science
2002, 295, 2395-2421.
3. G. de la Torre, C.G. Claessens, T. Torres Chem. Commun.
2007, 2000-2015.
4. G. Bottari, G. de la Torre, D. M. Guldi, T. Torres Chem. Rev.
2010, 110, 6768-6816.
5. G. Bottari, J. A. Suanzes, O. Trukhina, T. Torres J. Phys. Chem. Lett.
2011, 2, 905-913.
6. Manuscript in preparation.

Figure 1
Spectroscopic and Nonlinear Optical Properties of 3, (4-tert-butylphenoxy) Phthalocyanine Constitutional Isomers
Authors: Ngubeni Grace Nomthandazo , Britton Jonathan , Mack John , Nyokong Tebello , Khene Samson 
Published: February 2020

Introduction
Organic material with second-order nonlinear optical (NLO) material properties are useful in applications such as optical data processing or storage devices and can be easily processed and integrated into optical devices [1, 2]. Organic materials such as phthalocyanines (Pcs) exhibit large and fast nonlinearities, which can be fine-tuned by rational modification of the molecular structure [3, 4, 5]. Pc molecules are known to have large third-order optical nonlinearities which arise from the highly delocalised two dimensional 18-electron system [6, 7, 8, 5]. Pcs have been intensively investigated for their NLO properties. In most studies, NLO properties of tetra substituted Pcs have been studied as a mixture of isomers [9].
Aims
In this work four constitutional isomers of unmetalated tert-butylphenoxy phthalocyanine were separated and their NLO properties measured, in order to identify which isomer contributes the most to the measured NLO response.This work presents spectroscopic and nonlinear optical properties of unmetalated 3, (4-tert-butylphenoxy) phthalocyanine constitutional isomers. Second order nonlinear polarizability, second order hyperpolarizability and third order imaginary susceptibility (Im[χ(3)]) values were determined for monomeric and aggregated constitutional isomers.
Z-scan technique is employed in determining the second order NLO property. Spectroscopic and photophysical properties of the isomers, such as fluorescence lifetime and rotational correlation lifetimes are determined. Magnetic circular dichroism (MCD), time correlated single photon counting spectroscopy (TCSPC), ultra-violet visible (UV/vis) spectroscopy, Infra-red (IR) spectroscopy and density functional theory (DFT) are some of the techniques used to characterise physical properties of the isomers.
References

G. de la Torre, P. Va´zquez, F. Agullo´-Lo´pez, T. Torres, J. Mater. Chem., 1998, 8, 1671-1683.

T. Verbiest, S. Houbrechts, M. Kauranen, K. Clays, A. Persoons, J. Mater. Chem., 1997, 7, 2175-2189

J. M. Fox, T. J. Katz, S. V. Elshocht, T. Verbiest, M. Kauranen, A. Persoons, T. Thongpanchang, T. Krauss, L. Brus, J. Am. Chem. Soc.,1999, 121, 3453-3459

E. M. Maya, A. W. Snow, J. S. Shirk, R. G. S. Pong, S. R. Flom, G. L. Roberts, J. Mater. Chem., 2003, 13, 1603-1613

G. de la Torre, P. Vazquez, F. Agullo-Lopez and T. Torres, J. Mater. Chem., 1998, 8, 1671-1683.

J. Britton, M. Durmus ̧ S. Khene, V.Chauke, T. Nyokong, J. Porphyrins Phthalocyanine, 2013, 17, 692-702.

C. Mkhize, J. Britton, T. Nyokong, Polyhedron, 2014, 81, 607-613.

J. Britton, M. Durmuş, V. Chauke, T. Nyokong, Journal of Molecular Structure, 2013, 1054-1055, 209-214.

C. Nitschke, S. M. O’Flaherty, M. Kroll, J. J. Doyle, W. J. Blau, Chemical Physics Letters, 2004, 383, 555-560.
Point Defect Equilibria and Diffusion in Siderite (FeCO3) Passive Film Studied Using Density Functional Theory
Authors: Youssef Mostafa , Yildiz Bilge 
Published: February 2020

In a CO2-rich anoxic aqueous environment as in some oil fields, a layer of siderite (FeCO3) grows on carbon steel as a byproduct of steel corrosion. This layer acts as a resistive barrier that kinetically slows down further corrosion of steel. Understanding and predicting the rates of progression of both general and pitting corrosion requires a fundamental understanding of defect equilibria and diffusion in the passive film [1]. In this work we address this need by modelling point defect equilibria and mobility using a combination of density functional theory (DFT) and thermodynamic analysis. The defects of interest in this study are the native cation and anion vacancies and extrinsic chlorine defects whose concentrations vary depending on temperature and the chemical potential gradient from the steel/siderite interface (iron rich) to the siderite/water interface (carbonate rich). Defect formation energies were calculated using the DFT+U approach and defect mobility’s were computed the nudged elastic band method. Preliminary results indicate that iron vacancies are predominantly fully ionized (2- charge state), whereas oxygen vacancies are mainly neutral and carbon vacancies are never fully ionized (charge state less than 4-) as shown in Figure 1. In addition we identified hole polarons localized on iron cations to be a predominant electronic defect that participate in the equilibria of charged defects in this material.
The predictions of point defects thermodynamics and kinetics in FeCO3 is major step toward an atomistics-informed corrosion model of carbon steel in oil fields.
[1] D. D. Macdonald, Pure Appl. Chem., 71, 951, (1999).

Figure 1
Study of Stable Cathodes and Electrolytes for High Specific Density Lithium-Air Battery
Authors: Hernandez-Lugo Dionne , Zhu Yu 
Published: February 2020

Future NASA missions require high specific energy battery technologies, > 400 Wh/kg. Current NASA missions are using “state-of-the-art” (SOA) Li-ion batteries (LIB), which consist of a metal oxide cathode, a graphite anode and an organic electrolyte. The design and chemistry of these cells have safety issues and relatively low specific energy. Among all the advanced energy storage systems, metal-air batteries, especially lithium-air batteries comprise a new system that has the potential to significantly enhance the energy density (10,000 Wh/kg). It has been shown theoretically work that their energy density is comparable with that of gasoline. The most challenge is that the lithium-air batteries undergo severe degradation upon cycling which limit the cycle life. An intriguing possible solution can be found in pairing a pure sp2carbon cathode with a non-traditional electrolyte such as ionic liquids.
NASA Glenn Research Center is currently studying the physical and electrochemical properties of the anode-electrolyte interface for ionic liquid based Li-air batteries. The voltage-time profiles for Pyr13FSI and Pyr14TFSI ionic liquids electrolytes studies on symmetric cells show low overpontentials and no dendritic lithium morphology. Cyclic voltammetry measurements indicate that these ionic liquids have a wide electrochemical window. As a continuation of this work, sp2 carbon cathode and these low flamability electrolytes were paired and the physical and electrochemical properties were studied in a Li-air battery system under an oxygen environment.
Amorphous Metal Fluorides Coatings By Atomic Layer Deposition for Stable Li-Ion Batteries
Authors: Mane Anil U. , Park Joong Sun , Croy Jason R. , Elam Jeffrey W 
Published: February 2020

Metal fluorides pose interesting optical and chemical properties and thin films of these materials can be used in various applications to serve as optical coatings, protective layers, catalysts, solid state electrolytes, and barrier layers for thin film batteries. The properties of metal fluorides show broad trends based on the charge of the metal. Metals in an oxidation state of +3 or lower tend to form ionic, refractory fluorides. Metals of +5 oxidation or higher tend to form covalently bonded fluorides, polymers, and discrete molecules. Consequently, bi-metallic fluorides comprised of high and low valence metals might possess novel properties. The development of thin film methods for preparing these materials may pave the way for new applications of nanophase materials.
In order to reduce the unfavorable side reactions in Li-ion batteries, ultrathin metal oxides such as Al2O3, LiAlO2, and LiTaO3, deposited by atomic layer deposition, have been demonstrated [1,2] to significantly enhance both stability and safety of electrodes. However, metal oxide coatings are likely to be susceptible to hydrofluoric acid (HF) attack upon electrochemical cycling. Metal fluorides may be suitable alternatives for electrode coating materials due to their stability against HF attack and the strong bonding between metals and fluorine.
Here we report the atomic layer deposition of complex fluorides such as AlxWyFz and MgxWyFz utilizing WF6 as the source of both fluorine and the high valence metal with Al(CH3)3 (TMA) and Mg(Cp)2 [4]. In-situ quartz crystal microbalance studies were performed during the deposition of these chemistries and in both cases the QCM data showed self-limiting, linear growth. Films were prepared at 200oC and the deposited layers of AlxWyFz and MgxWyFz were found to be x-ray amorphous in nature. SEM EDAX elemental mapping of these layers, deposited in high aspect ratio trenches, showed uniform and conformal distributions of the various elements within the films, Figure 1. We have used ~1 nm layers of AlxWyFz and MgxWyFz materials in an effort to improve the performance of a model Li-ion battery cathode, LiCoO2 [5]. This presentation will present the results of ALD of these materials, characterization, and Li-ion battery stability tests.

References

(1) Jung, Y. S.; Cavanagh, A. S.; Dillon, A. C.; Groner, M. D.; George, S. M.; Lee, S.-H. Journal of The Electrochemical Society
2010, 157, A75.
(2) Park, J. S.; Meng, X.; Elam, J. W.; Hao, S.; Wolverton, C.; Kim, C.; Cabana, J. Chemistry of Materials
2014.
(3) Li, X.; Liu, J.; Banis, M. N.; Lushington, A.; Li, R.; Cai, M.; Sun, X. Energy & Environmental Science
2014, 7, 768.
(4) Anil U. Mane, and Jeffrey W. Elam, ALD (2014), Kyoto, Japan

(5) Park J. S, Mane A. U, Elam J. W., Croy J. R., Submitted to Chemistry of Materials

Figure 1
Density Functional Theory Study of Li Intercalation Voltage Near Cathode Interfaces
Authors: Xu Shenzhen , Jacobs Ryan , Wolverton Chris , Morgan Dane 
Published: February 2020

Interfaces are ubiquitous and important in battery electrode as they occur in regions of material intergrowth, in compositional gradients and also at interfaces with protective coatings. In this work, we study the Li intercalation voltage behavior across the interface of olivine FePO4-MPO4 (M=Co, Ti, Mn). These olivine-structured interfaces provide a representative model to help us further understand the physics of Li intercalation across material interfaces with different intercalation voltages. We find that as one moves across the interface from high to low Li intercalation voltage material the voltage stays constant in the higher voltage material and decays approximately linearly in the lower voltage region. This effect is shown to be due to electron transfer from the intercalated Li across the interface. The existence of the higher voltage material and the interface can significantly enhance the Li intercalation voltage in the lower voltage region within a 1-2 nm scale. Implications of this result for cathode structures will be discussed.
A High-Throughput Search for Functional Cathode Coatings for Lithium-Ion Batteries By First-Principles Thermodynamics
Authors: Aykol Muratahan , Kim Soo , Kirklin Scott J. , Morgan Dane , Wolverton Chris 
Published: February 2020

A widely employed remedy to slow down the degradation of the electrochemical performances of lithium-ion batteries (LIBs) is to apply coating materials on cathode surfaces.[1] Such coatings can serve as physical barriers to inhibit electrode-electrolyte side reactions, and they can possess an additional functionality such as scavenging the detrimental acids (e.g., the hydrofluoric acid, HF) in electrolytes. Recently, we introduced a density functional theory (DFT) based framework to find promising HF-scavenging binary metal oxide coatings by considering their HF-scavenging tendencies and lithiation voltages.[2] Building on that framework, here we present a new high-throughput (HT) coating design strategy to search among thousands of candidate oxide materials and find the most promising candidates.
In the current framework, we consider three main thermodynamic criteria to assess the effectiveness of a compound A
a
B
b
C
c
…O1/2 as a coating. First criterion is the thermodynamic stability of the candidate material. We evaluate this criterion by finding whether the material is stable against decomposition to other phases in its chemical space A-B-C-…-O. The second criterion is the electrochemical stability. This criterion tests whether the material is stable against reduction and oxidation during cycling. The third criterion is the HF-scavenging tendency. We evaluate this criterion for systems where an HF-scavenging functionality is preferred, by identifying the HF-scavenging reactions and free energies. In addition, we take into account the effect of different cathode-electrolyte chemistries on these three criteria, namely, presence of common cathode materials (LiCoO2, LiMn2O4, etc.), as well as presence of HF-free or HF-bearing electrolytes.
Utilizing the HT-coating design framework described above, we screen more than ~100,000 oxide materials available in the Open Quantum Materials Database (OQMD)[3] to find coating materials with different target properties. We suggest promising multi-component oxide cathode coatings that can prolong the cycle-lives of LIBs, and surpass the effectiveness of common coatings used such as Al2O3, MgO and ZrO2.

Acknowledgement

This work has been supported by The Dow Chemical Company.

References

[1] Z. Chen, Y. Qin, K. Amine, Y.-K. Sun, J. Mater. Chem.
2010, 20, 7606.
[2] M. Aykol, S. Kirklin, C. Wolverton, Adv. Energy Mater.
2014, in press.
[3] J. E. Saal, S. Kirklin, M. Aykol, B. Meredig, C. Wolverton, JOM
2013, 65, 1501.

Figure 1
(Invited) Fabrication of High-Quality TiO2 Nanotubes on Conductive Glasses
Authors: Li Shibin , Yang Xiaohui , Wei Xiongbang , Xuan Yaoyu , Chen Zhi David , Jiang Yadong 
Published: February 2020

In recent decades, titanium dioxide nanotube arrays has attracted many researcher’s interest due to their excellent physical and chemical properties, such as high order, large specific surface area, stability, and efficient electron transporting for dye-sensitized solar cells. However, it is difficult to prepare high quality TiO2 nanotubes on conductive glasses. Most TiO2 nanotubes on conductive glasses reported in literatures exhibit poor organized structures.
As shown in Fig.1, a highly self-ordered titania nanotube arrays have been prepared on conductive glass (SnO2:F) (FTO) substrates in ethylene glycol organic electrolyte which contains ammonium fluoride through anodic oxidation. The Ti film was deposited first on the FTO via DC magenetron sputtering. The sputtering power and substrate temperature were adjusted to obtain compact films. The incipient nanotubes have been covered by the surface oxide layer. To clean the surface, the sample after anodization was etched in diluted hydrofluoric acid solution via ultrasonic cleaning for a short time. Furthermore, the results indicate high quality TiO2 nanotubes on the conductive glass substrates can be fabricated by using longer oxidation time (2h).

Figure 1
(Invited) Applications of Electrochemistry for Novel Wide Bandgap GaN Devices
Authors: Park S. H. , Zhang C. , Yuan G. , Chen D. , Han Jung 
Published: February 2020

In the recent two decades we have witnessed phenomenal progress in GaN optoelectronic and power electronic devices, culminating in the recent 2014 Nobel Prize in Physics. In both light emitting devices and power transistors, GaN has transitioned from laboratory curiosity to commercial maturity. Most of the innovative claims nowadays need to be benchmarked with industrial manufacturability and cost effectiveness. We intend to show in this talk new opportunities rendered by applying electrochemistry to GaN.
Recently our group discovered a simple and versatile electrochemical (EC) etching of GaN at room temperature with no need of any ultraviolet irradiation.[i] The EC etching relies on the generation of holes at the GaN/electrolyte surface for oxidation and chemical dissolution. Depending on the layer conductivity and applied bias, the EC etching may cause no effect, nanoscale porosification, or complete etching of GaN.[ii] The EC etching has been applied to different areas of GaN material and device technologies, including layer separation, LED light extraction, the formation of distributed Bragg reflector (DBR) for photonic applications, and the preparation of flexible GaN membrane devices. Highlights from each application will be reviewed in this talk.
The work was supported by the U.S. Department of Energy, National Science Foundation (NSF), and Seoul Optodevices.

[i] Zhang, Y. et al., “A conductivity-based selective etching for next generation GaN devices”, Physica Status Solidi B 2010 247, 1713-1716
[ii] Zhang, Y. et al., “The fabrication of large-area, free-standing GaN by a novel nanoteching process”, Nanotechnology 2011, 22, 045603