bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid Screening of Novel LED Phosphors Using Melt Quenching Method
Authors: Toda Kenji , Kim Sun-Woog , Uematsu Kazuyoshi , Sato Mineo 
Published: February 2020

In order to develop novel LED phosphor materials, we applied novel synthesis technique, “Melt quenching synthesis” rather than the conventional solid state reaction technique. This synthesis technique is a general and powerful tool for rapid screening and improvements of new phosphor materials. As shown on fifure, a combinatorial melt synthesis reactor is designed to heat 24 small-size samples up to very high temperature like above 2200 K melt in clean conditions. Strong light emitted from a 6 kW xenon lamp is collected by an ellipsoidal mirror (collector) and directed to the sample. In the melt synthesis, the mixture of raw materials is melted in a short period of time (from 1 to 60 s) by a strong light radiation in arc imaging furnace. A spherical molten sample with multiple cations were mixed homogeneously at around 2200 K and directly solidified on a Cu hearth after closing the shutter. The cooling rate was estimated to be more than 100 K/s.
For example, Y3Al5O12:Ce3+ (YAG:Ce) is a most well-known yellow phosphor for white LEDs. Conventional synthesis technique of LED phosphor is a solid state reaction using the mixture of oxide or carbonate starting materials. The YAG: Ce phosphor synthesized by the high temperature solid state reaction shows agglomerate and irregular shape particles with inhomogeneous distribution of Ce3+ ions because of poor reactivity of high melting point raw materials, Al2O3 (melting point 2327 K) and Y2O3 (2706 K). The synthesis and morphology control of such complex oxide phosphor is not easy by the conventional solid-state reaction with several grinding and firing steps. A spherical phosphor ball samples were directly solidified on a Cu hearth and show bright emission by excitation of visible light. The melt process produces a well-grown YAG:Ce phosphor with useful lens-like morphology. YAG:Ce phosphors synthesized by the "melt synthesis technique” show superior luminescence property (10 – 20 % higher emission intensity) because of high crystallinity.
Well-crystallized and grown LED phosphors were synthesized by the new synthesis technique, “Melt quenching synthesis”. Polycrystal, glass and single-crystal LED phosphors were obtained in a quite short reaction time for melt quenchin reaction, which is a new useful and powerful method for synthesis of LED phosphors.

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(Invited) New Phosphor Exploration By the Single Particle Diagnosis Approach
Authors: Takeda Takashi , Funahashi Shiro , Xie Rong-Jun , Hirosaki Naoto 
Published: February 2020

The luminescence property of Eu2+ or Ce3+doped phosphor is so affected by the coordination environment of luminescent center. The usage of different host material leads to new phosphor. The search for new phosphor is roughly classified to two methods. One is to employ a known crystal structure that is suitable for luminescent center doping and is not studied for host crystal. However, the promising candidates are already studied in most cases. The other is to find new host material by analyzing single crystals or powder product. In the single crystal analysis, a large size crystal is necessary to determine the crystal structure. In the powder process, at least it is necessary to synthesize the new material as single phase to solve the crystal structure from powder XRD data. Both normally require much time and effort. We have developed a new efficient method to find new phosphors from a powder mixture synthesized by a standard process. We have named the new method “Single Particle Diagnosis Approach”. Even if the powder product is not a single phase, by considering each (isolated) particle, it can be treated as a single phase and a single crystal. The crystal structure and luminescence properties of candidate single particles are analyzed and new phosphors are efficiently discovered.
Here we show some examples. 1) In Ba3N2-Si3N4-AlN quasi-ternary system, seven luminescent particles with different colors and morphologies were selected from the twenty powder samples. Among them, two particles were found to be new phosphors (yellow Ba5Si11Al7N25:Eu2+ and blue BaSi4Al3N9:Eu2+)1. 2) In addition to above example, Li3N was employed as the fourth component. As the number of components increases, the number of experiments dramatically increases in the combinatorial synthesis. In the single particle diagnosis approach, the increment of experiments number is suppressed. From Ba3N2-Si3N4-AlN-Li3N quasi-quaternary system, we found new green phosphor Ba2LiSi7AlN12:Eu2+. It shows a narrow-band emission and a small decrease of luminescence intensity even at 300 °C 2. 3) An interesting example is a new orange phosphor using Sr3N2-Si3N4-AlN quasi-ternary system. XRD and EDS analyses showed the composition of new phosphor particle to be Sr2Si2+3xAl2-xB2-2xN8+x:Eu2+. Boron component is not included in the staring materials. It is contamination from BN crucible. By using BN powder and Mo crucible instead, Sr2Si2+3xAl2-xB2-2xN8+x Eu2+ was obtained as a main phase3. One of the merits of this approach is that the small amount of a new phosphor (including unintended new phosphors) in a powder sample is not overlooked.
1. N. Hirosaki, T. Takeda, S. Funahashi, R.-J. Xie. Chem. Mat. 26 (2014) 4280.
2. T. Takeda, N. Hirosaki, S. Funahashi, R.-J. Xie. Chem. Mat. 27 (2015) 5892.
3. S. Funahashi, Y. Michiue, T. Takeda, R.-J. Xie, N. Hirosaki, Acta Cryst. C70 (2014) 452.
(Invited) Biohybrid Photoelectrodes Exploiting Effective Photosystem I - Electrode Contacts
Authors: Lisdat Fred , Feifel Sven Christian , Stieger Kai 
Published: February 2020

Hybrid systems using the unique features of natural photosynthesis are increasingly in the focus of current research. Particularly the two protein complexes photosystem I and II (PS) of the oxygenic photosynthesis have attracted the attention of researchers to build up new solar energy-converting systems. In such biohybrid systems an efficient coupling of PS with the electrode is essential. Besides the light-to-current conversion, the PS may also be used for light-driven enzymatic reactions resulting in photobioelectrocatalysis.
Different basic principles can be used by establishing communication between the PS and electrode surfaces. Here we want to avoid shuttle molecules and generate a surface allowing direct electron transfer (DET) between the excited protein and the electrode. This has been studied with photosystem 1 (PSI) from Thermosynechococcus elongates.For efficient photocurrent generation a arther oriented immobilisation would be desirable which is complicated by the rather high molecular weight and the complex surface properties of PSI.
In this context we have been focusing on the directional assembly of PSI on highly conductive graphene electrodes. In order to adjust the surface properties different aromatic molecules have been applied onto the graphene [1]. The different Π-systems serve as an artificial scaffold harbouring functional groups which interplay with the PSI. Particularly important is the hydrophilic-hydrophobic balance on the surface. In conclusion, an effective and rather directed assembly of PSI and a large photocurrent density has been obtained. It has to be mentioned here that photocurrent generation occurs already at open circuit potential with now additional driving force applied. Depending on the modifier used an unidirectional photocurrent generation can be achieved by this approach. Via the artificially modified graphene surface we have been able to create biohybrid systems with an improved photocurrent output. Here not only adsorption can be used for the functional assembly but also covalent linkage of PSI to the surface. A systematic investigation on the protein assembly and the resulting photoelectrochemical properties will be presented. For this quartz crystal microbalance experiments, chopped light voltammetry, constant potential measurements, photoaction spectra and experiments with methyl viologen have been performed.
Moreover it can be demonstrated that the performance of such PSI electrodes can be further improved. Here nanoparticles are additionally coupled to the graphene-PSI system in order to enhance current generation under illumination.
[1] S. C. Feifel, K. R. Stieger, H. Lokstein, H. Lux, F. Lisdat, Journal of Materials Chemistry A 3 (23) (2015) 12188-12196
[2] S. C. Feifel, H. Lokstein, M. Hejazi, A. Zouni, F. Lisdat, Langmuir 31 (38) (2015) 10590-10598
Effects of Temperature and Calciums on the Treatment of Organics and Nutrient in Swine Wastewater Using an Integrated Bioelectrochemical Ion-Exchange System
Authors: Lim Seung Joo , Kim Tak-Hyun 
Published: February 2020

Introduction
Since husbandry industry has intensively developed, a great amount of high-strength swine wastewater has been generated. Even though several investigators have developed various processes for the treatment of swine wastewater, it was continuously required to develop more stable process high-strength wastewater. The objective of this paper was to investigate simultaneous removal of organic matter and nutrient in swine wastewater using an ion-exchange membrane system.
Materials and Methods
The ion-exchange membrane system consisted of three chamber (A, B and C) was separated by a cationic exchange membrane and an anionic exchange membrane(Figure 1). Ammonium ion in swine wastewater was ion-exchanged between a chamber A and a chamber B via a CEM. The ammonium ion was biologically oxidized to nitrate in a chamber B and nitrate was transported via an AEM and denitrified in a chamber C. Organic matter in the influent was acidified in a chamber A and used as electron donor for denitrification in a chamber C. COD, ammonia and phosphate used in this study were 9080.4 mg/L, 1910.6 mg/L and 43.2 mg/L.
Results and Discussion
Maximum COD and ammonia removal efficiencies were 86.4% and 78.4%. Average COD and ammonia removal were 77.1% and 63.6% in Figure 2. When temperature sharply decreased to 13oC, the ammonia removal efficiency maintained about 42.0% due to the high ammonium flux (1.54 mg N/m2/sec) and MLVSS ratio (0.83) in Figure 2. As shown in Figure 3, the maximum phosphate removal efficiency was 91.0% (Ave.: 59.7%), and the phosphate removal was highly correlated with calcium consumption. This shows that phosphorus can be removed as a Ca3(PO4)2 or the coprecipitation of phosphate with calcite.

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High Efficiency Insertion of Antibody-Immobilized Nanoneedle into Living Cells for in Situ detection of Cytoskeletal Proteins
Authors: Nakamura Chikashi , Shimizu Keita , Kawamura Ryuzo , Iijima Masumi , Kuroda Shun’ichi , Fukazawa Kyoko , Ishihara Kazuhiko 
Published: February 2020

We have been developed a technology to detect cytoskeletal proteins, such as actin microfilament (1), tubulin (2) and intermediate filaments (3) in living cells using antibody immobilized nanoneedle and AFM. The nanoneedle can be inserted into cells by penetrating membranes with minimal damage to cells due to the ultra-thin shape of 200 nm in diameter and aspect ratio over 50. In this in situprotein detection, force to rupture the interactions between antibodies and cytoskeletal proteins is evaluated. Even by using such thin material, there is a problem of low efficiency of penetration through plasma membrane owing to lipid bilayer’s high fluidity under the condition of normal cultivation temperature of 37°C. In this study, we investigated the effect of impact speed of nanoneedle and insertion under low temperature condition to improve the membrane-penetration efficiency.
We chose vimentin, a member of intermediate filaments, as a target protein, which is expressed in variety of cell species, e.g. mesenchymal cell. We immobilized anti-vimentin antibodies onto nanoneedle surface via bionanocapsules displaying Fc-binding ZZ domains derived from protein A. HeLa cells and MCF-7 cells were utilized as vimentin-positive and vimentin-negative cells, respectively. Magnitude of peak forces to rupture antibody-vimentin complexes which appear during the evacuation process of the nanoneedle from the cell was analyzed to evaluate effect of impact speed and temperature on the nanoneedle penetration efficiency. Although the impact speed of nanoneedle higher than 10 µm/s (conventional speed) did not show increment of fishing force detection efficiency, medium temperature of 4°C lower temperature obviously contributed to increment of the average fishing force, from 23 nN to 57 nN. The rupture force of singe interaction between the antibody and vimentin at 4°C was almost same that at 37°C. The results indicated that the temperature of 4°C was presumably under phase transition of the plasma membrane and the condition could enhance penetration of the nanoneedle.
(1) Silberberg, et al., Biosens. Bioelectron., 40, 3-9 (2013)
(2) Silberberg, et al., J. Biosci. Bioeng., 117, 107-112 (2014)
(3) Mieda, et al., Biosens. Bioelectron., 31, 323-329 (2012)
Anodic Chlorination of Chalcogenophenes in Conjugated Polymers
Authors: Inagi Shinsuke , Okazaki Daichi , Shida Naoki , Nishiyama Hiroki , Tomita Ikuyoshi 
Published: February 2020

We have developed the electrochemical post-functionalization method of π-conjugated polymers in the film state on an electrode. Among them, poly(3-hexylthiophene) was successfully chlorinated at the 4-position of the thiophene rings by anodic oxidation and following introduction of chloride ions used as a supporting salt.
In this study, we investigated the anodic chlorination of poly(3-alkylchalcogenophene)s including poly(3-alkylselenophene)s, copolymers of 3-alkylthiophenes and 3-alkylselenophenes. Constant potential electrolysis of these π-conjugated polymers proceeded to give the corresponding chlorinated polymers. Poly(3-hexylselenophene) exhibited higher reactivity than poly(3-hexylthiophene) owing to its lower oxidation potential. Chalcogenophene units having 2-ethylhexyl group at the 3-position did not undergo anodic chlorination probably due to the steric hindrance of the side chains. Accordingly, a block copolymer consisting of 3-hexylselenophene and 3-(2-ethylhexyl)thiophene was selectively chlorinated only in the poly(3-hexylselenophene) segments.

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Double Salt Ionic Liquids Containing the Trihexyl(tetradecyl)phosphonium Cation: The Ability to Tune the Solubility of Aromatics, Ethers, and Lipophilic Compounds
Authors: Wang Hui , Berton Paula , Myerson Allan S. , Rogers Robin Don 
Published: February 2020

Ionic liquids (ILs) certainly have some interesting properties and this has led to tremendous growth in interest, knowledge, and applications of these materials in a diverse array of science and technology. However, the field is still dominated by study of the simplest binary salts and an over reliance on ‘magic’ solvent properties which currently limits their creative use for new technologies. Lately, the scientific community has been attracted towards “IL/IL mixtures” prepared by mixing two or more ILs, and (as was the case with the early studies of the binary salts), a focus on specific physicochemical properties. Interestingly, crystalline salts dissolved in ILs are seen as a different class of liquids (e.g., high ionicity ILs). We have found that the physical, chemical, and biological (i.e., the materials) properties of IL/IL mixtures (or Double Salt Ionic Liquids, DSILs, as we like to call them) seem to be mainly controlled by the intrinsic ion interactions which are influenced by the exact ion composition. Perhaps, a new way of thinking about these multi-ion fluids is needed in order to direct research toward an understanding of the complex and varied types of interionic forces possible in a liquid. We have proposed the DSIL concept to help guide our work towards obtaining this deeper understanding. In this nomenclature, any homogeneous liquid containing three or more ions (no matter how they are prepared) are described as DSILs and are defined by the specific ion combinations present.
In this presentation, these concepts will be illustrated by discussion of the chemical, physical, and biological properties of several DSIL systems chosen to explore different interactions between the ions (i.e., Coulombic, hydrogen bonding, dispersion, etc.). While we will present physical properties as a function of composition, we will focus more on chemical properties illustrated by the solubilities of pharmaceuticals and on biological properties illustrated by changes in membrane transport, both as a function of ion composition. Spectroscopic studies will be presented to provide insight into specific ion-ion interactions. For example, the solubility of active pharmaceutical ingredients with different acidity and lipophilicity are finely tunable by varying the ratio of the ions (Figure 1). Such studies support the concept that each DSIL is a unique ionic fluid that is able to provide tunable property sets derived from the ions present and that these properties can be controlled by choosing the nature and the abundance of the ions.

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Spontaneous Reduction of Eu(III) in LiCl-KCl Melt: Spectroscopic and Rde Studies
Authors: Bae Sang-Eun , Lee Nari , Kim Jong-Yun , Park Tae-Hong , Kim Jongwon 
Published: February 2020

Pyrochemical process using molten salts has attracted much attention because of its potential to be applied to a future spent nuclear fuel management. In the pyrochemical process, electrochemical properties of lanthanide and actinide elements play a most important role in the recycling of the spent nuclear fuel. Therefore, it is important to know chemical and electrochemical behaviours of lanthanides and actinides in the molten salt for the successful developmentof the pyrochemical process. In this work, the spectro-electrochemical and rotating disk electrode (RDE) methods were employed to interrogate spontaneous reduction of Eu(III) ion, which is one of fission products, in LiCl-KCl eutectic at high temperature. By using the spectro-electrochemical system, the electrochemical potential of a working electrode can be controlled and, simultaneously, the evolution of the oxidation state of the Eu cation can be observed in the LiCl-KCl eutectic melt. RDE results can give information for electrochemical parameters such as diffusion coefficient, Tafel slope etc. as well as extent of the spontaneous reduction.
Fig. 1 shows UV-Vis absorption spectrum (a) and RDE results (b) of Eu(III) in LiCl-KCl melt. In the UV-Vis absorption spectrum, Eu(III) exhibits two broad and intense bands at 257 nm and 321 nm which are assigned f-d transitions of Eu(II).In the RDE results, oxidation current is also observed over +0.6 V. These results confirm that Eu(III) is spontaneously reduced to Eu(II) in LiCl-KCl. In this work, we performed UV-Vis absorption and RDE measurements of the Eu cations in LiCl-KCl at various temperature and evaluate how much Eu(III) is spontaneously reduced.

Fig. 1. UV-Vis absorption spectrum (a) and RDE results (b) of Eu(III) in LiCl-KCl melt.

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Cu2o/Nanocarbon Architectures for Photoelectrochemical CO2 Conversion: Synthetic Aspects and Structure-Property Relationships
Authors: Endrodi Balazs , Kecsenovity Egon , Rajeshwar Krishnan , Janáky Csaba 
Published: February 2020

Carbon nanomaterials, especially carbon nanotubes and graphene (either alone, or as building blocks of organized 3-D superstructures), are attracting significant attention as large surface area electrode support materials. Their composites with both inorganic and organic semiconductors represent an interesting class of new functional materials. In the first part of my talk I will briefly focus on the use of electrosynthetic (and photoelectrosynthetic) methods for preparing semiconductors on nanocarbon-modified electrode surfaces.1,2I will show how electrodeposition can be used to tune composition, crystal structure, and morphology of the nanocomposites for targeted applications.
In the second part of my talk, selected examples will be given for how these electrosynthesized hybrid assemblies can be deployed in photoelectrochemical CO2 conversion. Given that CO2 is a greenhouse gas, using sunlight to convert CO2 to transportation fuel (such as methanol) represents a value-added approach to the simultaneous generation of alternative fuels and environmental remediation of carbon emissions from the continued use of conventional fuels.3 I will present the controlled synthesis and photoelectrochemical behavior of Cu2O/CNT4 and Cu2O/3D graphene composites for the CO2 reduction application. A carefully designed, multiple-step electrodeposition protocol was developed that ensured homogeneous coating of the CNTs with the Cu2O nanocrystals. This enhanced charge transport property for the hybrids resulted in a drastic increase in the photocurrents measured for the CO2 reduction. In addition to this superior performance, long term photoelectrolysis measurements proved that the Cu2O/CNT hybrids were more stable than the oxide alone. Structure property relationships will be shown, which may act as guidelines for the rational design of nanocomposite photoelectrodes.

Figure 1. Illustration of the structure of the Cu2O/CNT composite and the increasing photocurrent with the increasing CNT-content.
[1] C. Janáky and K. Rajeshwar: The Role of (Photo)electrochemistry in the Rational Design of Hybrid Conducting Polymer / Semiconductor Assemblies: From Fundamental Concepts to Practical Applications, Prog Pol Sci, 43 (2015) 396-435
[2] C. Janáky, E. Kecsenovity, K. Rajeshwar: Electrodeposition of Inorganic Oxide/ Nanocarbon Composites: Opportunities and Challenges, ChemElectroChem, 3 (2016) 181-192
[3] G. Ghadimkhani, N. R. De Tacconi, W. Chanmanee, C. Janaky, K. Rajeshwar: Efficient solar photoelectrosynthesis of methanol from carbon dioxide using hybrid CuO/Cu2O semiconductor nanorod arrays, Chem. Commun. 49 (2013) 1297–1299
[4] E. Kecsenovity, B. Endrődi, Z. Pápa, K. Hernádi, K. Rajeshwar, C. Janáky: Decoration of ultralong carbon nanotubes with Cu2O nanocrystals: a hybrid platform for enhanced photoelectrochemical CO2 reduction, J Mater Chem A, 4 (2016) 3139-3147

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(Invited) Observing Photochemical Charge Transport at Particle Based Tandem Junctions for Overall Water Splitting
Authors: Osterloh Frank E. , De Melo Mauricio Alves , Yang Yuxin , Wang Jiarui 
Published: February 2020

Photochemical charge generation, separation, and transport across particle interfaces are central to photoelectrochemical water splitting, a pathway to hydrogen from solar energy. Here we use surface photovoltage spectroscopy (SPS) to probe these processes in films of BiVO4 and Rh:SrTiO3 particles on fluorine doped tin oxide (FTO) or p-doped silicon wafers. Particle films were made by drop-coating of premade particle suspensions in water followed by thermal annealing. Photochemical charge separation in the films was measured as a function of layer thickness and illumination intensity, and in the presence of sacrificial electron donors. The formation of Tandem junctions is clearly observed and to result in a maximum photovoltage of up to -150 mV under 0.3 mW cm-2 illumination. Charge separation is limited by light absorption and by slow electron transport. Overall Water Splitting with visible light an a quantum efficiency of 0.61% at 400 nm was observed with a direct contract tandem photocatalysts made of ruthenium-loaded Rh:SrTiO3 nanocrystals and of BiVO4 microcrystals. The activity and stability of this system depends on the temperature employed for generating the tandem junction. The ability to measure the built-in potential in particle junctions promotes the development of particle-based systems for artificial photosynthesis.

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