12 research outputs found
Investigation of the molybdenum oxide purification for the AMoRE experiment
No full textThe presented study reports on the purification of molybdenum oxide, which is one of the important tasks of the Advanced Mo based Rare process Experiment in searching for the neutrinoless double beta (0 nu beta beta) decay of Mo-100. Purified MoO3 powder is used as initial material for further growth of radiopure monocrystals. As purification technique, double sublimation, co-precipitation with calcium chloride carrier, and precipitation of polyammonium molybdate from acidic media were used. Concentrations of impurities like Sr, Ba, Pb, Th and U were measured by ICP-MS and radioactive isotopes were checked by a HPGe detector at the YangYang underground Laboratory in Korea1111sciescopu
증발 역학과 표면에너지 제어를 활용한 균일한 표면의 다중 나노입자 프린팅 방법
No full textThe present disclosure relates to a method of printing multi-nanoparticles using evaporation dynamics and surface energy control, the method includes: a step S1 of forming a pattern on a surface of a substrate by irradiating ultraviolet rays to a portion of the surface through a photomask; a step S2 of coating the substrate with a solution containing nanoparticles; and a step S3 of lowering surface energy of the coated nanoparticles
Noninvasive and Direct Patterning of High- Resolution Full-Color Quantum Dot Arrays by Programmed Microwetting
No full textAlthough the commercialization of electroluminescent quantum-dot (QD) displays essentially demands multicolor patterning of QDs with sufficient scalability and uniformity, the implementation of QD patterning in a light emitting diode device is highly challenging, mainly due to the innate vulnerability of QDs and charge-transport layers. Here, we introduce a noninvasive surface-wetting approach for patterning full-color QD arrays on a photoprogrammed hole transport layer (HTL). To achieve noninvasiveness of QD patterning, surface-specific modification of HTLs was performed without degrading their performance. Moreover, engineering the solvent evaporation kinetics allows area-selective wetting of QD patterns with a uniform thickness profile. Finally, multicolor QD patterning was enabled by preventing cross-contamination between different QD colloids via partial fluoroencapsulation of earlier-patterned QDs. Throughout the overall QD patterning process, the optoelectronic properties of QDs and hole-transport layers are well preserved, and prototype electroluminescent quantum dot light-emitting diode arrays with high current efficiency and brightness were realized.
A cryogenic setup for multifunctional characterization of luminescence and scintillation properties of single crystals
No full text© 2020 Author(s). This article reports on a cryogenic setup that can be used for multifunctional experimental purposes. The temperature of the setup can be set from 10 K to 300 K. Different kinds of experiments were carried out in this experimental setup such as (1) luminescence emission, light yield, and decay time measurement under excitation of 266 nm laser and 280 nm LED sources, (2) thermoluminescence (TL) measurement under an x-ray excitation source, (3) scintillation property measurements such as light output, energy resolution, and decay time under 137Cs (662 keV γ-rays) and 241Am (5.4 MeV α) isotope sources, and (4) scintillation measurement under a 90Sr beta source through the continuous single-photon counting technique. The luminescence and scintillation properties of various molybdate and tungstate crystals such as CaMoO4, Na2Mo2O7, Pb2MoO5, CdWO4, and ZnWO4 are characterized and reported in the present work. The TL measurement of a CaMoO4 crystal is carried out from 10 K to 300 K, and various kinetic parameters such as order of kinetics, frequency factor, activation energy, and figure of merit are calculated for different TL peaks. As the temperature goes down from room to 10 K, the light yield of all studied crystals increases. Since the light yield of the crystal increases as temperature decreases toward 10 K, this experimental setup can be used for the characterization of luminescence and scintillation properties of a single crystal for rare event searches such as neutrinoless double-beta decay and dark matter11sciescopu
Highly Efficient Deep Blue Cd‐Free Quantum Dot Light‐Emitting Diodes by a p‐Type Doped Emissive Layer
No full textNoninvasive and Direct Patterning of High-Resolution Full-Color Quantum Dot Arrays by Programmed Microwetting
No full textAlthough the commercialization of electroluminescent
quantum-dot
(QD) displays essentially demands multicolor patterning of QDs with
sufficient scalability and uniformity, the implementation of QD patterning
in a light-emitting diode device is highly challenging, mainly due
to the innate vulnerability of QDs and charge-transport layers. Here,
we introduce a noninvasive surface-wetting approach for patterning
full-color QD arrays on a photoprogrammed hole-transport layer (HTL).
To achieve noninvasiveness of QD patterning, surface-specific modification
of HTLs was performed without degrading their performance. Moreover,
engineering the solvent evaporation kinetics allows area-selective
wetting of QD patterns with a uniform thickness profile. Finally,
multicolor QD patterning was enabled by preventing cross-contamination
between different QD colloids via partial fluoro-encapsulation of
earlier-patterned QDs. Throughout the overall QD patterning process,
the optoelectronic properties of QDs and hole-transport layers are
well preserved, and prototype electroluminescent quantum dot light-emitting
diode arrays with high current efficiency and brightness were realized
Strong constraints from COSINE-100 on the DAMA dark matter results using the same sodium iodide target
No full text© 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).We present new constraints on dark matter interactions using 1.7 years of COSINE-100 data. The COSINE-100 experiment, consisting of 106 kg of tallium-doped sodium iodide [NaI(Tl)] target material, is aimed to test DAMA's claim of dark matter observation using the same NaI(Tl) detectors. Improved event selection requirements, a more precise understanding of the detector background, and the use of a larger dataset considerably enhance the COSINE-100 sensitivity for dark matter detection. No signal consistent with the dark matter interaction is identified and rules out model-dependent dark matter interpretations of the DAMA signals in the specific context of standard halo model with the same NaI(Tl) target for various interaction hypotheses.11Nsciescopu
