bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Novel Intramolecular Charge-Transfer Molecules Bearing Triphenylamine and Benzothiadiazole Moieties, and Application to Single-Absorber Organic Solar Cells
Authors: Okuda Yuki , Suenobu Tomoyoshi , Nakayama Kenichi 
Published: February 2020

Organic solar cells (OSCs) have been extensively studied due to their potential for flexible, printable, and low-cost devices. Recently, power conversion efficiency (PCE) has reached around 10% by using bulkhetero junction (BHJ) system which possesses miscible interface between two kinds of materials, electron donor and acceptor. In the BHJ system, LUMO offset is required to promote charge separation at donor-acceptor interface, causing serious photovoltage loss.
In order to overcome this problem, we have pursued the possibility of single-absorber organic solar cells, whose active organic layer consists of one component. Generally, photogeneration efficiency in organic bulk film is quite low because of the large exciton binding energy (EBE). In previous work, we found that molecules with intramolecular charge transfer photoabsorption are suitable for the single-absorber OSC. A donor-acceptor (D-A) linked molecule DTDCPB (Fig. 1) was applied to the single absorber OSC, and comparatively good performance was obtained.
In this study, we synthesized novel donor-acceptor linked molecules bearing triphenylamine and benzothiadiazole moieties by derivatizing DTDCPB (Fig. 1). DTDCPB was extended by insertion of thienothiophene at the donor-acceptor linkage part to form DTDCPB-TT. DTERPB and DTRCNPB bear an acceptor moiety of 3-ethyl rhodanine and 2-(3-ethyl-4-oxothiazolidin-2-ylidene)malononitrile, respectively, instead of dicyanovinyl moiety. EBEs in the solid state were estimated with quantum chemical calculation to design a suitable molecule for lower EBE.
The D-A molecules were applied to a single absorber OSC composed of ITO/PEDOT:PSS/organic/Ca/Al. In the DTDCPB-TT device, FF and hole mobility increased compared with those in the DTDCPB device because the film crystallinity was improved due to thienothiophene. In the DTERPB and DTRCNPB devices, the photovoltage loss was only 0.60 V, that was less than that of the typical BHJ system. The ratio of the voltage loss to the absorbed energy was 33% for DTERPB and 35% for DTRCNPB, which were rather small in comparison with the typical BHJ system, e.g. 65% for P3HT:PC61BM and 56% for PTB7:PC71BM.

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Fabrication of Polymer Bonded Permanent Magnets
Authors: Khosla Ajit , Vaid Rakesh , Thundat Thomas , Nagahara Larry A. , Kawakami Masaru , Furukawa Hidemitsu 
Published: February 2020

We present fabrication of polymer bonded magnets. These magnets were fabricated by mixing isotropic permanent magnetic Neodymium Iron Boron (NdFeB) fine powder in polydimethylsiloxne matrix (PDMS). The developed magnetic composite can be be micromolded on flexible PDMS substrate, via a novel hybrid soft lithographic technique previously reported by authors {1, 2, 3].
The developed PDMS based magnets find their application in microfluidics [4], Sensors and actuators [5], micromotors [6] and automotive industry [7]
References:

Khosla, A., and B. L. Gray. "New technologies for large-scale micropatterning of functional nanocomposite polymers." In Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2012, vol. 8344, p. 83440W. International Society for Optics and Photonics, 2012. https://doi.org/10.1117/12.915178

Khosla, Ajit, Jasmine L. Korčok, Bonnie L. Gray, Daniel B. Leznoff, Jim Herchenroeder, David Miller, and Zhongmin Chen. "Fabrication of UV-micro-patternable permanent micro magnets for lab on a chip and MEMS." In Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2010, vol. 7646, p. 76461L. International Society for Optics and Photonics, 2010. https://doi.org/10.1117/12.847288

Rahbar, Mona, Sam Seyfollahi, Ajit Khosla, Bonnie L. Gray, and Lesley Shannon. "Fabrication process for electromagnetic actuators compatible with polymer based microfluidic devices." ECS Transactions 41, no. 20 (2012): 7-17. doi: 10.1149/1.3687433

Khosla, A., J. L. Korčok, B. L. Gray, D. B. Leznoff, J. W. Herchenroeder, D. Miller, and Z. Chen. "Fabrication and testing of integrated permanent micromagnets for microfluidic systems." In Microfluidics, BioMEMS, and Medical Microsystems VIII, vol. 7593, p. 759316. International Society for Optics and Photonics, 2010. https://doi.org/10.1117/12.840942

Khosla, Ajit, and Sam Kassegne. "Fabrication of NdFeB-based permanent rare-earth micromagnets by novel hybrid micromolding process." Microsystem Technologies 21, no. 11 (2015): 2315-2320. https://doi.org/10.1007/s00542-014-2331-4

Khosla, Ajit. "Micropatternable multifunctional nanocomposite polymers for flexible soft MEMS applications." PhD diss., Applied Science: School of Engineering Science, 2011. http://summit.sfu.ca/item/12017

Gray, Bonnie, Daniel B. Leznoff, Jasmine L. Korcok, and Ajit Khosla. "Compositions Including Magnetic Materials." U.S. Patent Application 12/772,090, filed June 23, 2011.
Operando Study of Lithium Dendrite Growth on Graphite Andoe By EC-AFM
Authors: Shen Cai 
Published: February 2020

Lithium dendrite growth is one of the most challenging problems affecting safety performance of lithium ion batteries (LIBs). It causes low Columbic efficiency as well as safety hazards for LIBs. Understanding the evolution process of Li dendrite growth at nanoscale is critical for solving this problem.
Herein, we report an in-situ electrochemical atomic force microscopy (EC-AFM) investigation of the initial Li deposition in EC and FEC-based electrolytes on graphite electrodes. Our results showed solid electrolyte interphase (SEI) formed from FEC-based electrolyte can suppress Li dendrite growth. FEC-based electrolyte induced formation of LiF-rich SEI films which were harder and denser than that formed in EC-based electrolyte. Combining with its better mechanical property and larger resistance, the SEI layer formed from FEC-based electrolyte is sufficient to slow down Li+ ions intercalation, prevent reduction of Li+ ions and Li deposition get electrons to deposit on the graphite surface. Our results demonstrated that EC-AFM is a powerful in-situ technique for the study of lithium dendrite growth.
Evaluation of Polymeric Binders in Aqueous Electrolyte Environment
Authors: Pace Gordon Taylor , Wu Wei 
Published: February 2020

Energy storage systems utilizing aqueous electrolytes are ever increasing in importance, as they are inherently cheap and safe when compared to their traditional lithium ion battery counter parts. To date, however, no thorough study on binder characteristics in the aqueous environment has been published. This work characterizes an acrylic based polymer, LA133, LA133+Carboxymethyl cellulose (CMC), Styrene-butadiene rubber (SBR), SBR+CMC, and Polytetrafluoroethylene (PTFE) in an LiMn2O4 cathode. Data presented includes cyclic voltammetry (CV), resistivity, and porosity. Future work will focus on characterizing binders for anode materials then galvanostatic cycling of full cells.
Figure 1 shows half-cell (CV) data for LiMn2O4 cathodes cycled between 0-0.7 V at reference cycle rates of 3.33 mV/min and daily cycles rates of 30 mV/min. LA133 clearly degrades, while the other binders performed similarly. This is noteworthy, as it directly contradicts LA133’s behavior in organic electrolytes, as Wang, Rui et al. specifically selected it for its stability in the window of 0.1-3.0V [1]. Additionally, SBR appears to have poorer performance at faster scan rates, but the overall slow scan retention was on par with that of Acrylic and PTFE, indicating poor rate capability rather than electrode degradation. Overall slow scan retention is shown more clearly in Figure 2. This again contradicts findings from traditional Li-ion batteries, as Yingjin Wei et al. selected the SBR/CMC binder combination for its superior rate capability [2].
Figure 3 shows resistivity and porosity data for the LiMn2O4 cathodes. Measurements were taken at 10 MPa and 19 MPa of applied pressure, and the average values are presented here. The most noteworthy point is that the addition of CMC clearly reduces the resistivity in both LA133 and SBR. This motivates investigation into pairing CMC with the other binders, which is not traditionally done in Li-ion batteries.
References

Wang R, Feng L, Yang W, et al. Effect of Different Binders on the Electrochemical Performance of Metal Oxide Anode for Lithium-Ion Batteries. Nanoscale Res Lett. 2017;12(1):575. Published 2017 Oct 30. doi:10.1186/s11671-017-2348-6

Yan X, Zhang Y, Zhu K, Gao Y, Zhang D, Chen G, Wang C, Wei Y (2014) Enhanced electrochemical properties of TiO2(B) nanoribbons using the styrene butadiene rubber and sodium carboxyl methyl cellulose water binder. J. Power Sources

Figure 1
(Invited) A Review of Defects in 2D Metal Dichalcogenides: Doping, Alloys, Interfaces, Vacancies and Their Effects in Catalysis & Optical Emission
Authors: Terrones Maurcio 
Published: February 2020

Two-dimensional transition metal dichalcogenides (TMDs) such as MoS2 and WS2 hold great promise for many novel applications. Recent years have therefore witnessed tremendous efforts on large scale manufacturing of these 2D crystals. A long-standing puzzle in the field is the effect of different types of defects in their electronic, magnetic, catalytic and optical properties. In this presentation an overview of different defects in transmission metal di-chalcogenides (TMDs) will be presented [1,2]. We will first focus on: 1) defining the dimensionalities and atomic structures of defects; 2) pathways to generating structural defects during and after synthesis and, 3) the effects of having defects on the physico-chemical properties and applications. We will also emphasize doping and allowing monolayers of MoS2 and WS2, and their implications in electronic and thermal transport. We will also describe the catalytic effects of edges, vacancies and local strain observed in MoxW(1-x)S2 monolayers by correlating the hydrogen evolution reaction (HER) with aberration corrected scanning transmission electron microscopy (AC-HRSTEM) [3]. Our findings demonstrates that it is now possible to use chalcogenide layers for the fabrication of more effective catalytic substrates, however, defect control is required to tailor their performance. By studying photoluminescence spectra, atomic structure imaging, and band structure calculations, we also demonstrate that the most dominating synthetic defect—sulfur monovacancies in TMDs, is responsible for a new low temperature excitonic transition peak in photoluminescence 300 meV away from the neutral exciton emission [4]. We further show that these neutral excitons bind to sulfur mono-vacancies at low temperature, and the recombination of bound excitons provides a unique spectroscopic signature of sulfur mono-vacancies [4]. However, at room temperature, this unique spectroscopic signature completely disappears due to thermal dissociation of bound excitons [4]. Finally, hetero-interfaces in TMDs, will be studied and discussed by AC-HRSTEM and optical emission.
References
[1] Z. Lin, M. Terrones, et al. “Defect engineering of two-dimensional transition metal dichalcogenides”. 2D Materials 3 (2016) 022002.
[2] R. Lv, M. Terrones, et al. "Two-dimensional transition metal dichalcogenides: Clusters, ribbons, sheets and more". Nano Today 10 (2015) 559-592.
[3] Y. Lei, M. Terrones, et al. "Low temperature synthesis of heterostructures of transition metal dichalcogenide alloys (WxMo1-xS2) and graphene with superior catalytic performance for hydrogen evolution". ACS Nano, 11 (2017), 5103-5112.
[4] V. Carozo, M. Terrones, et al. “Optical identification of sulfur vacancies: Bound excitons at the edges of monolayer tungsten disulfide”, Sci. Adv. 3 (2017), e1602813
(Invited) Temperature Works Against Symmetry but “Fortunately” It Does Not Always Win: The Example of Formation of Actinide Endohedral Metallofullerenes
Authors: Poblet Josep M. , Morales-Martinez Roser , Abella Laura , Rodriguez-Fortea Antonio , Zhuang Jiaxin , Chen Ning , Cai Wenting , Echegoyen Luis 
Published: February 2020

For almost two decades, intensive work from experimental and theoretical groups has made it possible to advance in the understanding of structural and electronic properties of endohedral metallofullerenes and cluster metal fullerenes. Hence, several groups have proposed diverse rules related with the relative stability of fullerene cages.1-4 All of them considered the potential energy when they predict the stability of IPR and non-IPR isomers based on the ionic model, in which the guest transfers usually between three and six electrons to the hosting carbon cage. Those guidelines have explained why the highly symmetric C80(I
h) cage is the preferred fullerene when there is a transfer of six electrons, like in the well-known Sc3N@C80,4 or in many other examples, such as Lu3N@C80, La2@C80, Y3@C80, etc.5 In endohedral fullerenes with four or less electron transfer between host and guest, there is not a prevalent structure, like C80(I
h), and the diversity of captured carbon cages is larger, the theoretical prediction of the most abundant species to be formed in a K-H reactor being much more difficult. In addition to the relative potential energy, it is also necessary to consider the enthalpic and entropic contributions to the stability of the endohedral fullerenes. A systematic theoretical analysis for a series of A@C2n fullerenes with A = Th and U, in combination with accurate experimental characterization, have allowed us to show that the structures of A4+@C2n
4- species are different from those of cluster fullerenes, such as Sc2O4+@C2n
4-, Sc2S4+@C2n
4-or Sc2C2
4+@C2n
4-. Here, we will discuss on the electronic structure and the peculiarities in host-guest interactions and cage selection in actinide endohedral metallofullerenes. Our observations support that there is a thermodynamic control in the fullerene formation at the high temperatures in which the carbon cages are formed (>1500 K), which in many cases determines that the actinide captures chiral IPR and non-IPR isomers of low-symmetry, in contrast with cluster fullerene encapsulation where different carbon cages are selected.
References
1- Campanera, J. M.; Bo, C.; Poblet, J. M., Angew. Chem., Int. Ed.
2005,
44, 7230-7233
2- Rodríguez-Fortea, A.; Alegret, N.; Balch, A. L.; Poblet, J. M., Nature Chem.
2010,
2, 955.
3- Garcia-Borràs M., Osuna S., Swart M., Luis J.M., Solà M. Angew.
Chem. Int.. Ed.
2013, 52, 9275-9278.
4- Wang, Y.; Díaz-Tendero, S.; Martín, F. and Alcamí, M. J. Am. Chem. Soc.,
2016, 138, 1551–1560
5- Stevenson, S.; Rice, G.; Glass, T.; Harich, K.; Cromer, F.; Jordan, M. R.; Craft, J.; Hadju, E.; Bible, R.; Olmstead, M. M.; Maitra, K.; Fisher, A. J.; Balch, A. L.; Dorn, H. C., Nature
1999,
401, 55.
6- Popov, A. A.; Yang, S.; Dunsch, L., Chem. Rev.
2013,
113, 5989-6113.
Potential Applications of Layered Double Hydroxides in Membrane-Based Separation and Anti-Corrosion
Authors: Liu Yi 
Published: February 2020

Layered double hydroxides (LDHs) are representative of inorganic layered compounds consisting of positively charged brucite-like sheets and charge compensating anions located in interlayer galleries. The high length-to-width ratio, uniform gallery height, flexible chemical compositions, active surface functionality and unique calcination properties of LDHs have inspired us to explore their potentials in gas separation. In the presentation we demonstrated that LDHs not only enabled to effectively separate hydrogen-containing gas mixtures relying on the uniform interlayer galleries, but also could serve as efficient perch, active heterogeneous nucleation center and qualified single metal source of MOF crystals for the preparation of high performance MOF membranes.
In addition, potential applications of LDHs in anti-corrosion were further explored. Relying on the dense in-plane structure of LDHs, preferentially c-oriented NiAl-CO3 LDH coatings were prepared showing excellent anti-corrosion performance. In addition, well-intergrown MOF coatings exhibiting excellent anti-corrosion performance could be in situ grown on Al substrates further by simple solvothermal treatment of ZnAl-CO3 LDH buffer layers. To sum up, full utilization of both microstructural and physicochemical properties of LDHs had greatly expanded their potential applications in membrane-based separation and anti-corrosion.
(Invited) (sSNOM) Imaging of 2D Encapsulated Ga Layered Metal
Authors: Rotkin Slava V. 
Published: February 2020

Plasmonic properties of newly discovered class of 2‐dimensional materials (2DM): one‐to‐few monolayer thick metals synthesized using confinement heteroepitaxy (CHet)1 will be discussed. Optical properties of 2DM are modulated at the ultimate scale of (a few) nanometers, thus the characterization also requires a similar spatial resolution. Scattering‐type scanning near‐field optical microscope (sSNOM) allowed us to reveal surface impedance of the 2D‐Ga layers coated with bilayer graphene. 2D‐Ga has extremely large optical contrast due to high density of states, resulting in ultimate light‐matter interactions within an atomic layer. 2D‐Ga was shown to not cover the surface uniformly, leaving the valleys of lower contrast. sSNOM data has been analyzed with two novel algorithms: impedance clustering (revealing metal encapsulation) and photonic decay curves (via 3D sSNOM mapping). Photonic decay is directly related to surface plasmonic density of states, the quantity of interest for nanophotonics applications of 2D‐metals.
Author acknowledges Mr. M. Blades for help with data processing, Dr. T. Gokus (Neaspec) – for sSNOM instrumentation, and Prof. J. Robinson (PSU) – for CHet material synthesis. This research was partially supported by the NSF ECCS‐1509786, and Penn State Quantum Characterization Infrastructure initiative.
[1] N.Briggs, B.Bersch, A.De La Fuente Duran, Y.Wang, A.Li, C.Navarro, J.Robinson, EP03.15.03 : Two‐Dimensional Monoelemental Materials via Confinement Heteroepitaxy, MRS Fall Meeting, Boston MA, 11/25‐30/2018.

Figure 1
(Invited) Atomically Precise Graphene Nanoribbons: From Synthesis to Applications
Authors: Sinitskii Alexander 
Published: February 2020

Atomically precise graphene nanoribbons (GNRs) are at the forefront of nanocarbon research and hold great promise for electronic and optoelectronic applications. Theoretical studies have shown that narrow GNRs possess interesting electronic and magnetic properties that strongly depend on the nanoribbon’s width and edge structure. GNRs with different structures can be synthesized with atomic precision and fine-tuned properties by coupling properly designed molecular precursors and planarization of the resulting polymers.
In this talk, I will discuss our efforts on designing and synthesizing new atomically precise GNRs for electronic applications. First, I will describe a scalable bottom-up solution approach for atomically precise GNRs that is based on Yamamoto coupling of pre-synthesized molecular precursors followed by cyclodehydrogenation using Scholl reaction. This approch can be applied to the synthesis of a variety of GNRs, including pristine and nitrogen-doped GNRs with the chevron structure. Then, I will demonstrate that the electrical conductivity of atomically precise chevron GNRs can be improved by their lateral extension. Two types of new laterally extended chevron GNRs (eGNRs) were synthesized in solution, and their high structural quality was confirmed by a number of characterization techniques, including high-resolution scanning tunneling microscopy and Raman spectroscopy combined with a computational analysis. Optical spectroscopy and scanning tunneling spectroscopy showed that lateral extension of chevron GNRs resulted in the decrease of their electronic bandgap.
We developed a procedure for processing eGNRs into uniform thin films that exhibit improved electrical conductivity compared to similar films of regular chevron GNRs. The eGNR films were employed in gas sensors that showed very high responsivity to low molecular weight alcohols compared to similar sensors based on benchmark graphitic materials, such as graphene and graphene oxide. Finally, we demonstrated the first electronic nose system based on atomically precise GNRs that could reliably recognize analytes of nearly the same chemical nature, such as methanol and ethanol. Overall, this talk will demonstrate the entire path from designing new atomically precise GNRs with improved properties to their bottom-up synthesis, characterization, processing and implementation in electronic devices.
(Invited) Electronic Structure and Raman Fingerprint of Atomically Precise Graphene Nanoribbons – a Key for Integration in Devices.
Authors: Senkovskiy Boris V. , Lindfors Klas , Fischer Felix R. , Grueneis Alexander 
Published: February 2020

Graphene nanoribbons (GNRs) are a novel tunable material that combines the best attributes of graphene and carbon nanotube worlds. We present our recent results on the electronic, optical and vibrational properties of atomically precise GNRs, particularly, pristine and boron-doped armchair graphene nanoribbons of N = 7 carbon atoms width (7-AGNRs and B-7AGNRs). Spatially aligned GNRs are synthesized by bottom-up approach on stepped Au surface. Using angle-resolved photoemission spectroscopy (ARPES) we reveal energy band dispersion of these systems. ARPES data allow us to determine the energies of one-dimensional sub-bands and the effective masses of charge carriers, which are important for charge transport characterization. Using ultra-high vacuum Raman spectroscopy we probe phonons of air-sensitive B-7AGNRs in situ and reveal the existence of characteristic splittings and red-shifts of vibration modes due to the presence of boron atoms. We perform transfer of 7-AGNRs on to the insulating substrate, which allows tuning and probing their optical response. Particularly, bright photoluminescence in 7-AGNRs is controllably induced by defect-engineering. Finally, we partially transform N=7 to narrow-gap N=14 AGNRs via lateral edge fusion on large-area surface. The band structure of 14-AGNRs is visualized by ARPES. Raman fingerprint allows easy identification of type and orientation of GNRs on both metallic and insulating substrates. The fused GNRs are also integrated in the field-effect transistor.
References:
[1] B.V. Senkovskiy, et al. Nano Lett. 2017, 17, 4029–4037
[2] B.V. Senkovskiy et al. 2D Materials 2018, 5, 035007
[3] B.V. Senkovskiy, et al. ACS Nano 2018, 12, 7571–7582
Corrections were made to this article on 6 March 2020. A typo was removed from author Felix R. Fischer's name.