Daegu Gyeongbuk Institute of Science and Technology
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Highly efficient pure red light-emitting diodes through surface bromination of CsPbI3 perovskite nanocrystals for skin-attachable displays
No full textMetal halide perovskites, known for their outstanding optical properties such as high photoluminescence quantum yield, exceptional color purity, and tunable bandgap, have emerged as promising semiconductor materials for next-generation display technologies. Nonetheless, producing pure red emissions from ∼ 10 nm-sized CsPbI3 perovskite nanocrystals (PeNCs) remains a significant challenge for perovskite light-emitting didoes (PeLEDs). Here, we present the facile surface bromination strategy of CsPbI3 PeNCs for pure red PeLEDs. The mild post-ligand treatment on CsPbI3 PeNCs produces surface-brominated PeNCs, denoted as CsPbI3:Br, while preserving the original CsPbI3 crystal structure intact. The resulting CsPbI3:Br PeNCs exhibit bright pure red luminescence and significant improvements in electrical properties. The PeLEDs, fabricated with these PeNCs, achieve a remarkable external quantum efficiency (EQE) of 19.8 %, comparable to those of the best reported pure red PeLEDs. Finally, we have showcased the application of these PeLEDs as skin-attachable PeLEDs, showing stable operations under various mechanical deformations. This study not only provides a straightforward method for producing pure red PeNCs, but also highlights their potential in wearable electronic applications. © 2024 Elsevier LtdFALSEsciescopu
Nickel Nanoparticles Confined in Core-Shell Derived from Covalent Organic Framework for the Efficient Electrocatalytic NO Reduction to NH3
No full textThe electrocatalytic nitric oxide reduction reaction (NORR) has attracted significant attention as an ecofriendly alternative to the conventional Haber-Bosch process for producing ammonia (NH3). However, the poor selectivity to NH3 and low catalyst stability under harsh conditions are great challenges in NORR. Herein, the core-shell structure of nickel nanoparticles enclosed with a nitrogen-doped carbon layer (Ni@NC) electrocatalyst derived from covalent organic frameworks is employed for high performance in NORR. The Ni@NC-700 achieved the highest FENH3 of 82.94% with an NH3 yield rate of 19.00 mu mol cm(-2) h(-1) at 0.16 V (vs reversible hydrogen electrode) in a 0.1 M HClO4 electrolyte. Control experiments revealed that nickel nanoparticles (Ni NPs) acted as active centers in Ni@NC for efficient production of NH3. The ideal carbon shell protection of Ni NPs and the high inherent catalytic TOF of Ni@NC-700 revealed a promising candidate for an efficient NORR electrocatalyst. The stability test demonstrated the remarkable stability of Ni@NC. The Ni NPs were protected by carbon nanostructures resembling core-shell catalysts, preventing metal dissolution during rough electrolysis.FALSEsciescopu
Hybrid nanogenerator for self-powered object recognition
No full textEnergy harvesting systems, including piezoelectric (PENG), triboelectric (TENG), and pyroelectric (PYNG) nanogenerator technologies, have emerged as one of the major future energy solutions. Energy harvesting eliminates the need for conventional batteries and encourages eco-friendly alternatives. This study reports hydrothermally synthesized BaTiO3 (BTO) particles with a tetragonal symmetry for hybrid energy harvesting. BTO particles are incorporated with PDMS at various wt% to form a flexible composite film. The 15 wt% BTO-PDMS composite/Al hybrid device (PENG-TENG) produces a peak voltage of 100 V, a current of 980 nA, and a charge of 17 nC, generating a peak power output of 33.64 μW at 100 MΩ. Furthermore, integrating this HNG (external hybridization) yielded an output of 101 V and 980 nA, demonstrating practical applicability. HNG is also employed to interact by touching various objects at different temperatures. The pyroelectric behavior of BTO allows direct thermal sensing of the object. The signals produced are processed using a convolutional neural network (CNN)-based object recognition system, which achieved a remarkable classification accuracy of 99.27% for various objects. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications. This research paves the way for developing hybrid energy harvesters and can be employed further for extremely precise battery-free object recognition systems. This unique hybrid nanogenerator, which combines pyroelectric, piezoelectric, and triboelectric components, represents a new method of self-powered object detection. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications. © 2024 Vietnam National University, HanoiFALSEsciescopu
Structural Dynamics Analysis of USP14 Activation by AKT-Mediated Phosphorylation
Get PDFUbiquitin-specific protease 14 (USP14), one of the three major proteasome-associated deubiquitinating enzymes (DUBs), is known to be activated by the AKT-mediated phosphorylation at Ser432. Thereby, AKT can regulate global protein degradation by controlling the ubiquitin-proteasome system (UPS). However, the exact molecular mechanism of USP14 activation by AKT phosphorylation at the atomic level remains unknown. By performing the molecular dynamics (MD) simulation of the USP14 catalytic domain at three different states (inactive, active, and USP14-ubiquitin complex), we characterized the change in structural dynamics by phosphorylation. We observed that the Ser432 phosphorylation induced substantial conformational changes of USP14 in the blocking loop (BL) region to fold it from an open loop into a β-sheet, which is critical for USP14 activation. Furthermore, phosphorylation also increased the frequency of critical hydrogen bonding and salt bridge interactions between USP14 and ubiquitin, which is essential for DUB activity. Structural dynamics insights from this study pinpoint the important local conformational landscape of USP14 by the phosphorylation event, which would be critical for understanding USP14-mediated proteasome regulation and designing future therapeutics. © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).TRUEsciescopu
Therapeutic patch for gastrointestinal tract and manufacturing method thereof
No full text본 발명의 다양한 실시예에 따른 위장관용 치료용 패치는 점막 접착성 재료; 및 상기 점막 접착성 재료에 담지되는 자성 나노입자 및 생체에 전달하기 위한 약물을 포함할 수 있다. 본 발명의 다양한 실시예에 따른 위장관용 치료용 패치의 제조 방법은, 점막 접착성 폴리머를 준비하는 단계; 카테콜 전구체를 준비하는 단계; 상기 점막 접착성 폴리머 및 카테콜 전구체를 혼합하는 단계; 상기 혼합하는 단계에서의 혼합물을 동결건조하는 단계; 상기 동결건조하는 단계로부터 수득된 분말과 자성 나노입자 및 약물을 혼합하는 단계; 및 상기 혼합물을 몰드를 이용하여 성형 후 동결건조하는 단계를 포함할 수 있다
Innovative Synthesis of Zeolitic Imidazolate Framework by a Stovetop Kitchen Pressure Cook Pot for Triboelectric Nanogenerator
No full textThis study presents a novel approach utilizing solvothermal techniques to synthesize zeolitic imidazolate framework (ZIF-4) particles. Various properties of the ZIF-4 particles are investigated to shed light on the structural and morphological characteristics. These ZIF-4 particles act as a positive triboelectric layer in the fabrication of a triboelectric nanogenerator (TENG) designed for powering electronic devices. The solvothermal-assisted synthesis ensures the controlled and efficient production of ZIF-4, optimizing its characteristics for enhanced performance in the TENG. The generated TENG, based on ZIF-4 particles, determines promising capabilities in converting mechanical energy into electrical power. The highest power of TENG is obtained to be 18 μW at a load resistance of 50 MΩ. This work contributes major insights to the search for sustainable and effective power solutions for electronic gadgets. It emphasizes the potential of ZIF-4 as a crucial triboelectric material, demonstrating its importance in the advancement of TENGs. © 2024 Wiley-VCH GmbHFALSEsciescopu
Stimulating and inhibiting neurons using dual-color micro-LEDs in a single implantable device
No full textBidirectional optogenetics holds promise as tool for neuromodulation. In a recent issue of Cell Reports Physical Science, Mao et al. introduced a monolithic neural probe with densely integrated dual-color red and blue micro-LEDs and microelectrodes achieved through heterogeneous stacking of III-V epitaxial films. In vivo demonstrations highlight the potential of the device to be used in brain circuit research and therapeutic applications. © 2023 Elsevier Inc.FALSEscopu
Fabrication and electrochemical performance of Ni-Cu carbonate/ hydroxide-based electrodes for high-performance supercapacitors
No full textThe increasing usage of high-performance equipment necessitates the exploration of new energy storage solutions. Supercapacitors offer significant advantages over secondary batteries, including longer lifespan, faster charge/discharge rates, higher power density, and greater reliability. Three-dimensional porous NiCu(CO3)(OH)2 nanowires were directly synthesized on Ni foam using a binder-free hydrothermal method as positive electrodes in high-performance supercapacitors. The unique nanowire structure of NiCu(CO3)(OH)2 plays a pivotal role in enhancing electrical performance by providing substantial surface area, improving electrode/electrolyte contact, and shortening ion diffusion paths. The use of Ni- and Cu-based binary transition metal electrodes contributes to high specific capacitance, rapid charge-discharge rates, and excellent cycling stability, collectively resulting in the development of high-capacity supercapacitors. Furthermore, density functional theory calculations were employed to elucidate the electrode formation energy based on the Ni/Cu ratio, assessing the structural stability of electrodes and offering insights for future energy storage device development. The optimized NiCu(CO3)(OH)2 nanowire compound exhibited an outstanding maximum specific capacity of 211.1 mAh g−1 at 3 A g−1. Furthermore, an asymmetric supercapacitor was constructed using the NiCu(CO3)(OH)2 composite as the positive electrode and graphene as the negative electrode. The resulting asymmetric supercapacitors demonstrate a remarkable energy density of 26.7 W h kg−1 at a power density of 2534 W kg−1, along with exceptional cycling stability, retaining 91.3% of its capacity after 5000 cycles. Consequently, the asymmetric supercapacitors incorporating NiCu(CO3)(OH)2 exhibit superior electrical properties compared to most previously reported Ni- and Cu-based asymmetric supercapacitors. © 2024 Elsevier B.V.FALSEsciescopu