bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microelectrode-Less Control of Semiconducting Fluorescent Nanoparticles By Dielectrophoretic (DEP) Force for High Degree of Freedom
Authors: Kim Jinsik , Kim Hyejin , Hwang Kyo Seon 
Published: February 2020

In previous our research, we introduced attachment or detachment of 25nm diameter quantum dots (QDs) manipulating method and 100nm diameter polystyrene (PS) nano-beads at nano sized metal structures by dielectrophoretic (DEP) force. The metal nano-structures were connected with micro electrode to apply the DEP force for trapping the nanoparticles. The DEP force is easily controllable by frequency and intensity of applied electric field. And the DEP force is very sufficient to manipulate the fluorescent nanoparticles at specific nanostructures, due to the large difference of electric fields inducement around nanostructures. The trapped fluorescent nanoparticles at nano metal structures which can be considered and called as a composited structure of photon emitting nanoparticles and nano structures could be utilized in study of coupling photons to plasmon waveguides as a real single photon generator. And the nanoparticle manipulating method could accomplish the additional composite structures without any chemical reactions as a lithographic method of fluorescent nanoparticles which can be used in QD display. The QDs are the most important and remarkable candidates nanoparticles to produce photon-emitting in quantum devices and display. However, the previous research had limitations such as limiting the variety of nanostructure, degree of freedom, and attaching sites due to the connected microelectrodes. And additional fabrication steps should be needed after the manipulation of nanoparticles to metal structures.
In this paper, we introduced the manipulation of QD which is composed with cadmium selenide, the semiconducting materials at the nanostructures by DEP force for plasmonic applications and QD display. For the high degree of freedom, the nanostructures didn’t connect with microelectrodes. Various shapes of nano structures which is made of gold are accomplished between the micro electrodes. The microelectrodes were not connected with the nano-structures. Wire, Y-branch and vertex shape of nanostructure were fabricated with e-beam lithography and lift-off process. The distance between microelectrodes and nanostructures was also calculated to optimize the condition of QD trapping with multiphysics simulation. Possibility of selective manipulation of QDs was also performed through the theoretical approaches at various shape of nanostructures by using the DEP force. Each shape of structures was considered to manipulate the QDs at the nanostructures. The selective manipulation which is attaching-side, position, end-facet selective in nanostructures provide the three degrees of freedom in attachment in the same structure. Consequently, the semiconductor materials based fluorescent nanoparticles, QDs, are successfully manipulated at nano-structures without any connecting with microelectrodes.
Direct Visualization of Stress Distribution Related to Adhesive through Mechanoluminescence
Authors: Terasaki Nao , Fujio Yuki , Sakata Yoshitaro , Uehara Masato , Tabaru Tatsuo 
Published: February 2020

Elasticoluminescent material is a novel ML functional ceramic powder (controllable size: 10 nm―100 μm, representative and the most efficient ML material: SrAl2O4:Eu2+) and it can emit intensive light repeatedly accompanied by mechanical stress such as deformation, friction, impact, even in elastic deformation region. The ML intensity is proportional to strain energy of the material. Thus, when dispersedly coated onto a structure, each particle acts as a sensitive mechanical sensor, while the two-dimensional (2D) emission pattern of the whole assembly reflects the dynamical strain/stress distribution inside the structure and the mechanical information around the defect and crack or the in-visible tip. This ML visualization technique provides a novel way of diagnosing the structural health, especially in early detection for safe & security measure. Actually, the ML sensor has been applied to real social infra-structure such as bridge, building, welding point of pipeline and high pressure vessel, and successfully demonstrated the ability to detect active crack including likelihood for growth, real crack propagation and mechanically weak points etc.
Meanwhile, recently NEW advanced material such as CFRP, high tensile strengthen steel and non-steel metal for light weight vehicle are strongly required from the viewpoint of energy saving and environment. Accordingly, joint & adhesive technologies especially for different kinds of materials and the non-destructive evaluation have been investigating for application of these materials and the reliability in use. Especially, as to adhesion, kissing bond and weak bond, in which strengthen of the bonding is nothing or weak respectively without void and crack, have been remaining as challenge for the application and has been vigorously investigated in the field of non-destruct evaluation so far.
In the presentation, we would like to report on suitability of the ML sensing for diagnosing (1) a stress distribution in adhesive, (2) visualization of mechanical distribution related to adhesive condition. In fact, as the result of (1), we succeeded to directly visualize stress distribution in adhesive for the first time through mechanoluminescence. We will discuss the results with the result of conventional FEM analysis, simulation of mechanical stress distribution. In addition, as the result of (2), we succeeded to visualize strass/strain distribution of adherend, clearly find out the stress/strain distribution are related to adhesion condition and also find out the area of pseud kissing bond through mechanoluminescence for the first time.
[Acknowledgement] The research was partially supported by Innovative Structural Materials Association (ISMA), program for the promotion of scientific research with a view to creating intellectual resources through New Energy and Industrial Technology Development Organization (NEDO), AIST Strategic budget 2015 and KAKENHI, Grant-in-Aid for Scientific Research (B).
(Invited) Impact of LED Implementation on Rare-Earth Usage in Lighting
Authors: Ku Anthony , Setlur Anant A 
Published: February 2020

Several rare earth elements are used in phosphors for fluorescent lighting: a significant fraction of global demand for yttrium, europium, and terbium have beenfrom lighting applications. Solid-state lighting products based on InGaN light emitting diodes (LEDs) are in the process of taking over the general illumination market due to their higher energy efficiency, lifetime, and packaging flexibility. . While LED phosphors also use yttrium and europium, the quantities required are much lower than what is needed to produce an equivalent amount of light using fluorescent bulbs. This dynamic suggests that rare earth oxide demand for lighting will peak and then decline off of current usage levels. This paper presents a simple order of magnitude analysis to estimate when this peak is expected to occur, based on projected LED adoption rates in different regions. We also discuss some of the implications for the supply-demand balance for rare earth elements.
Both Directional Organic Light-Emitting Diodes Using Thin Film Electrodes
Authors: Lee Jong-Lam , Lee Illhwan 
Published: February 2020

Recently, transparent organic light-emitting diodes (TOLEDs) have attracted much interest, because they can open new applications for bi-directional displays, transparent displays, wearable displays, smart glass, and window lighting. Typically, the device structure of TOLEDs needs to consist of an ITO bottom anode, emitting layer, and a thin metal cathode. To protect underlying organic layer from sputtering damage, a thin metal-based semi-transparent cathode was necessarily used by thermal evaporation. In this system, there were many problems in application of ITO electrodes to high efficient TOLEDs.
First, these TOLEDs usually have a preferential one-sided emission due to differences in reflection between ITO and Ag electrodes. In particular, the ITO-side emission ratio has a strong intensity which is more than 70% of the total emission ratio because of the relatively low reflection of ITO compared with Ag film. Second, the majority of the light generated in the organic layers is confined in the ITO anode and glass substrates due to the large difference in the refractive index between their layers. This results in out-coupling efficiencies of around only 20% due to the total internal reflection at the ITO / glass and glass / air interfaces. These problems can be solved by employing a thin metal (Ag) electrode as an ITO alternative. However, it is very difficult to form smooth and very thin Ag layers for transparent anode. Ag layers exhibit three-dimensional island growth as a result of the poor wettability of Ag on the substrate. A discrete Ag film consisting of an island structure exhibits strong absorption and scattering of incident light, because of localized surface plasmon resonance. Thus, thin Ag film was not considered as a transparent electrode for TOLED.
Here, we demonstrate an innovative method to make transparent and high performance OLEDs on substrates using only ultra-thin Ag electrodes as both the top and bottom transparent electrodes. We show that merely a minute-plasma treatment on the glass before the deposition of Ag layer leads to significantly improved growth homogeneity of the Ag layer. The ultra-thin Ag film is formed after oxygen plasma treatment, leading to improved visible range transmittance and sheet resistance. By designing the weak micro-cavity structure with the ultra-thin Ag electrodes, waveguide modes could be suppressed and optical transmittance of TOLEDs could be improved. According to FDTD simulation, waveguide modes in ITO and glass substrate can be remarkably extracted because of weak micro-cavity effect. Consequently, the luminance of TOLED could be improved by 47 %. In addition, the transmittance of TOLED with the ultra-thin Ag electrode showed a high transmittance (73.84 %), which was similar than that of ITO (73.19%). The optimized weak micro-cavity structured shows the high optical transmittance, identical emission rate and reduced wave-guided mode were achieved, enhancing the luminance of devices.
Ooptically and Thermally Stimulated Luminescence in x-Ray Irradiated Sn-Doped Sro-B2O3 and ZnO-P2O3 Glasses for Passive-Type Dosimeter
Authors: Nanto Hidehito , Nankagawa Ryota , Takei Yoshinori , Hirasawa Kazuki , Miyamoto Yuka , Masai Hirokazu , Masai Hirokazu , Okada Go , Yanagida Takayuki 
Published: February 2020

Optically and thermally stimulated luminescence (OSL and TSL) phenomenon is based on the presence of electron and/or hole traps and luminescence centers in storage phosphor materials. During exposure to ionizing radiation such as x-ray, γ-ray and β-ray, the traps are occupied with charged carriers such as electrons and holes that are created by irradiation with ionizing radiation. De-trapping of these carriers requires energy. The energy is provided by stimulating of the phosphor materials with visible or infrared light (OSL) or by heating of the phosphor (TSL). During a de-trapping transition, free carriers created by the absorption of photons from the stimulating radiation field, recombine with the luminescence centers, whereby visible photons are emitted. Since the OSL or TSL intensity is in the most cases proportional to absorbed dose of ionizing radiation, the phosphor materials which exhibit the OSL and TSL phenomena adapt to two-dimensional imaging sensor for ionizing radiation.
Although imaging plate (IP) using photostimulable phosphor materials such as BaFBr:Eu [1,2] and CsBr:Eu [3] can be now used as two-dimensional sensor for ionizing radiation, these phosphor materials with deliquescent property exhibit poor fading characteristics which is one problem on two dimensional radiation dose estimation using the IP. As a result of surveying many possible phosphor materials, we found that SnO-doped SrO-B2O3 and ZnO-P2O3 glass without deliquescent properties exhibit an efficient OSL and TSL, and good fading characteristics. In this work, the OSL and TSL characteristics in x-ray irradiated SrO-B2O3 and ZnO-P2O3 glasses are in the first time reported.
Ref.
[1] K.Takahashi et al., J. Electrochemcal Soc., 32 (1985) 1492.
[2] M.Takebe and K.Abe, Nuclear Instruments and Methods, A345 (1994) 606.
[3]H.Nanto et al., Nuclear Instruments and Methods, A580 (2007)278.
Fabrication of Y2O3:Bi3+,Eu3+ Fluorescent Nanosheet Films By Electrophoretic Deposition
Authors: Kosuge Yuta , Iso Yoshiki , Isobe Tetsuhiko 
Published: February 2020

Spectral down-shifters convert near-UV light, to which silicon solar cells typically have low sensitivity, to visible light that solar cells can convert to electric power. They can therefore improve the photoelectric conversion efficiency of the solar cells. Y2O3:Bi3+,Eu3+ nanosheets absorb near-UV light and emit red light. The nanosheets possess high photostability under the continuous near-UV excitation. In this study, we make efforts to fabricate Y2O3:Bi3+,Eu3+fluorescent nanosheet films on ITO-coated glass substrates by electrophoretic deposition.
Bi(NO3)3･5H2O (0.004 mmol) was dissolved in ethylene glycol (2.6 mL). Y(NO3)3･6H2O (0.956 mmol) and Eu(NO3)3･6H2O (0.040 mmol) were dissolved in ultrapure water (30 mL). The aqueous solution was added to the ethylene glycol solution, and then the mixed solution was mixed with triethylamine (3 mL). The total volume of the suspension was adjusted to 40 mL by adding ultrapure water, and the resulting suspension was heated in an autoclave at 160 °C . After centrifugation and freeze-drying, the powdered product was heated to 600 °C and kept at that temperature for 2 h to obtain calcined sample. The calcined sample was mixed with an aqueous solution of trisodium citrate, and stirred for 2 h. Citrate-modified nanosheets were re-dispersed to an NaOH aqueous solution (pH=11). An aqueous emulsion of silicone-modified acrylic resin was added to the nanosheet suspension as a binder. A nanosheet film was fabricated on an ITO-coated glass substrate at the anode side by application of a constant voltage in the prepared suspension.
The absolute values of zeta potentials of Y2O3: Bi3+,Eu3+ nanosheets dispersed in ultrapure water increased after modification with citrate ions. The increase in zeta potentials verifies that citrate ions act as a stabilizing agent to prevent aggregation of the nanosheets. The deposited film exhibited red luminescence under UV light. According to SEM observation, the film was composed of Y2O3: Bi3+,Eu3+ nanosheets and nanoparticles of silicone-modified acrylic resin.
Upconversion Emission from Li-Gd2O3 Phosphors Embedded into PS Films
Authors: Carmona-Tellez S. , Carro-Gastelum A. , Mariscal B. L. , Alarcon-Flores G. , Huerta Evelyn , Medina-Velazquez D. , Falcony Ciro 
Published: February 2020

Dielectric materials doped with rare earth (RE3+) ions have received large attention due to their potential application in photonic devices. In particular, upconversion (UC) luminescence has been widely studied as a way to obtain visible light using lasers operating in the infrared region as excitation light. In general, in order to observe efficient UC emissions the host material should have low cutoff phonon frequency to allow for large lifetime decay of the RE ion excited electronic levels. In addition, UC efficiencies depend on the doping strategy used, for instance, using co-dopants as Yb and Li ions has been reported to increase the UC efficiency on Tm3+ doped materials.
In the present work, UC luminescence from Li-Gd2O3 phosphors doped with Tm3+ and Yb3+ and its incorporation into Polystyrene (PS) films are studied, under continuous wave excitation at 980 nm. Powder samples were prepared by simple evaporation technique. They were characterized using x-ray diffraction, SEM and and photoluminescet spectroscopy; a study of UC emission from Tm3+ ions as well as Yb3+ was performed. Yb3+ presence makes possible the thulium blue emission in the UC luminescence model, meanwhile lithium presence could increase the Tm light emissions due to a notable change into gadolinium oxide structure. Those phosphors were attached into PS films by spin coating technique, these films were characterized using IR spectroscopy, UV-Vis and AFM as well as SEM and photoluminescent spectroscopy. They have high transparency (close to 98%) and are also activated under continuous wave excitation at 980 nm.
Cathodoluminescence in Rare Earth Doped Perovskite Films for RGB Colors
Authors: Takashima Hiroshi , Nagao Masayoshi 
Published: February 2020

We have studied PL and EL properties of chemically stable perovskite phosphor films. Pr-doped Ca0.6Sr0.4TiO3 perovskite films were grown epitaxially on SrTiO3 (001) substrates and their intense red luminescence were observed. The PL intensity was markedly increased by post-annealing treatments, and the maximum PL intensity was obtained by the combination of relatively low-temperature film growth at 600 °C and sequential rapid post-annealing at 1000 °C. 1 We have discovered perovskite thin film electroluminescence, opening a new optical application of regarding perovskite materials. Complete epitaxial growth of all of the layers and very flat interfaces with monoatomic steps have been obtained. With increasing driving voltage, the intensity of electroluminescence dramatically increases. The sharp electroluminescence peak at around 610 nm at 12 V becomes much stronger with increasing ac voltage. High-quality red color is produced and the working voltage for whole-surface electroluminescence is as low as 10 V. 2 The electron beam irradiation was a method of obtaining electrical and optically emitting. In this report, we show preparation of cathodoluminescence in perovskite films for RGB colors. The films were grown on double-side polished SrTiO3 (001) substrates by pulsed laser deposition. The single-phase polycrystalline targets were prepared by a conventional solid-state reaction method. Compositions of green, blue and red were [(Ca0
.
97Mg0
.
03)0
.
98Tb0
.
02]SnO3, Sr2(Sn0.95Ti0.05)O4 and Pr0.002(Ca0.6Sr0.4)0.997TiO3, respectively. During film growth, the SrTiO3 substrates were heated to 600 °C for film and the oxygen partial pressure was controlled at 50 Pa. An ArF excimer laser (λ = 193 nm) was used that had a repetition rate of 8 Hz and a fluence of around 1.2 J cm−2 pulse−1 at the target surface. In order to take out luminescence excited by the electron beam from the side opposite to with a film adhesion side, the both-side polished substrate which has about 70% (at 500nm) of transparent was used. The field emitter with a gate electrode was used for the source of electrons. The transmittance of film with both-side polished substrate after 1000°C post-annealing treatments was 67 % (at 500nm), indicating that the transmittance of the epitaxially grown alkaline-earth stannates film is very high. When the phosphor film of [(Ca0
.
97Mg0
.
03)0
.
98Tb0
.
02]SnO3was irradiated with the electron beam, the cathode luminescence peaks were observed at around 490, 543, 582, 620 nm. These results clearly show that CL has been successfully obtained in the perovskite films. By using thin film phosphor for FED, high resolution could be realized and it is efficient and also possibility of a long-life.

REFERENCES

(1) H. Takashima, et al,
Applied Physics Letters. 89 261915 (2006).
(2) H. Takashima, et al, Advanced Materials
.
21 3699 (2009)
Synthesis, Structure and Luminescence of Mn4+- Doped ATiO3 (A=Ca, Mg, Zn) Deep Red Phosphors
Authors: Medic Mina , Brik Mikhail G. , Srivastava Alok M , Djordjevic Vesna , Papan Jelena , Dramicanin Miroslav 
Published: February 2020

Red emission of the Mn4+ ions incorporated in different materials is used in various applications, such as lighting and holographic recording. Mn4+ emission can improve color-rendering-index of phosphor-converted white-light-emitting diodes, and it is a promising candidate to replace the well-established rare-earth Eu activator in red phosphors.
Here, synthesis, structure, morphology, and detailed spectroscopic and crystal field analysis of Mn4+ doped metal titanates ATiO3 (A = Ca, Mg, Zn) are presented. Materials were prepared by combining sol-gel and molten salt methods. In the first step a typical sol-gel procedure is applied in which acetic acid, absolute ethanol, tetrabutyl titanate and metal compound were mixed at the molar ratio of 3:16:1:1 with appropriate amount of manganeze nitrate hexahydrate. In the second step, obtained dry gels were mixed with eutectic salt NaCl/KCl = 1:1 at molar ratio of 1:10, and then calcined at 750oC. Structural analysis was done by X-ray diffraction for all samples. Optical characterization included measurements of photoluminescence excitation and emission spectra, emission decay analyses and diffuse reflection measurements. Optical spectra showed emission and absorption bands originating from d–d electronic transitions (a d3 configuration). The energy levels of the Mn4+ ions in the crystal field of ATiO3 are calculated using the exchange charge model and showed nice matching with the experimental photoluminescence excitation and emission spectra.
(Invited) Red-Emitting Manganese-Doped Aluminum Nitride Phosphor
Authors: Cherepy Nerine , Payne Stephen , Harvey Nicholas , Aberg Daniel , Seeley Zachary , Holliday Kiel , Tran Ich , Zhou Fei , Martinez H. Paul , Demeyer Jessica , Drobshoff Alexander , Srivastava Alok M , Camardello Samuel , Comanzo Holly A , Schlagel Deborah , Lograsso Thomas 
Published: February 2020

We report high efficiency luminescence with a manganese-doped aluminum nitride red-emitting phosphor under 254 nm excitation, as well as its excellent lumen maintenance in fluorescent lamp conditions, making it a candidate replacement for the widely deployed europium-doped yttria red phosphor. Solid-state reaction of aluminum nitride powders with manganese metal at 1900 °C, 10 atm N2 in a reducing environment results in nitrogen deficiency, as revealed by diffuse reflectance spectra. When these powders are subsequently annealed in flowing nitrogen at 1650 °C, higher nitrogen content is recovered, resulting in white powders. Silicon was added to samples as an oxygen getter to improve emission efficiency. NEXAFS spectra and DFT calculations indicate that the Mn dopant is divalent. From DFT calculations, the UV absorption band is proposed to be due to an aluminum vacancy coupled with oxygen impurity dopants, and Mn2+ is assumed to be closely associated with this site. In contrast with some previous reports, we find that the highest quantum efficiency with 254 nm excitation (Q.E. = 0.86±0.14) is obtained in aluminum nitride with a low manganese doping level of 0.06 mol%. The principal Mn2+ decay of 1.25 ms is assigned to non-interacting Mn sites, while additional components in the microsecond range appear with higher Mn doping, consistent with Mn clustering and resultant exchange coupling. Slower components are present in samples with low Mn doping, as well as strong afterglow, assigned to trapping on shallow traps followed by detrapping and subsequent trapping on Mn.

Figure 1