A5077429844- Quantum and electron transport phenomena
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Magnetic properties of thin films
- Quantum Dots Synthesis And Properties
- Conducting polymers and applications
- Organic Light-Emitting Diodes Research
- Surface Chemistry and Catalysis
- Advanced Memory and Neural Computing
- Chalcogenide Semiconductor Thin Films
- Laser-induced spectroscopy and plasma
- Low-power high-performance VLSI design
- VLSI and Analog Circuit Testing
- Magnetism in coordination complexes
- Advanced Chemical Physics Studies
- Surface and Thin Film Phenomena
- Organic Electronics and Photovoltaics
- Mechanical and Optical Resonators
- Vehicle emissions and performance
- CCD and CMOS Imaging Sensors
- Solid-state spectroscopy and crystallography
- Porphyrin and Phthalocyanine Chemistry
- Analytical chemistry methods development
- Machine Learning in Materials Science
- Transition Metal Oxide Nanomaterials
Center for Quantum Nanoscience
2018-2025
Institute for Basic Science
2018-2025
Seoul National University
2017-2025
Ewha Womans University
2019-2025
Johannes Kepler University of Linz
2018-2025
Quantum Technologies (Sweden)
2025
Ewha Womans University Medical Center
2021
Pohang University of Science and Technology
2015-2018
TU Bergakademie Freiberg
2018
NanoTecCenter Weiz Forschungsgesellschaft (Austria)
2014-2015
Brighter perovskite LEDs Organic-inorganic hybrid perovskites such as methyl ammonium lead halides are attractive low-cost light-emitting diode (LED) emitters. This is because, unlike many inorganic nanomaterials, they have very high color purity. Cho et al. made two modifications to address the main drawback of these materials, their low luminescent efficiency. They created nanograin materials lacking free metallic lead, which helped confine excitons and avoid quenching. The had a current...
Efficient quasi-2D-structure perovskite light-emitting diodes (4.90 cd A−1) are demonstrated by mixing a 3D-structured material (methyl ammonium lead bromide) and 2D-structured (phenylethyl bromide), which can be ascribed to better film uniformity, enhanced exciton confinement, reduced trap density. As service our authors readers, this journal provides supporting information supplied the authors. Such materials peer reviewed may re-organized for online delivery, but not copy-edited or...
Planar CH3NH3PbI3 perovskite solar cells with constant 17.2% average power conversion efficiency irrespective of the scan rate are described. These properties attributed to formation a pure CH3 NH3 PbI3 thin film by introduction HI solution. Thereby, charge-injection/separation efficiency, charge-collection diffusion coefficient, carrier lifetime, and traps improved. As service our authors readers, this journal provides supporting information supplied authors. Such materials peer reviewed...
Organometal halide perovskite synaptic devices are fabricated; they emulate important working principles of a biological synapse, including excitatory postsynaptic current, paired-pulse facilitation, short-term plasticity, long-term and spike-timing dependent plasticity. These properties originate from possible ion migration in the ion-rich matrix. This work has extensive applicability practical significance neuromorphic electronics.
Colloidal metal–halide perovskite quantum dots (QDs) with a dimension less than the exciton Bohr diameter DB (quantum size regime) emerged as promising light emitters due to their spectrally narrow light, facile color tuning, and high photoluminescence efficiency (PLQE). However, size-sensitive emission wavelength purity low electroluminescence are still challenging aspects. Here, we demonstrate highly efficient light-emitting diodes (LEDs) based on colloidal nanocrystals (NCs) in > (regime...
Pure green light-emitting diodes (LEDs) are essential for realizing an ultrawide color gamut in next-generation displays, as is defined by the recommendation (Rec.) 2020 standard. However, because human eye more sensitive to spectral region, it not yet possible achieve ultrapure electroluminescence (EL) with a sufficiently narrow bandwidth that covers >95% of Rec. standard CIE 1931 space. Here, we demonstrate efficient, EL based on colloidal two-dimensional (2D) formamidinium lead bromide...
This paper reports highly bright and efficient CsPbBr3 perovskite light-emitting diodes (PeLEDs) fabricated by simple one-step spin-coating of uniform polycrystalline layers on a self-organized buffer hole injection layer stoichiometry-controlled precursor solutions with an optimized concentration. The PeLEDs have maximum current efficiency 5.39 cd A-1 luminance 13752 m-2 . also investigates the origin hysteresis, which can be ascribed to migration Br- anions. Temperature dependence...
Highly efficient, simplified, solution-processed thermally activated delayed-fluorescence organic light-emitting diodes can be realized by using pure-organic delayed fluorescence emitters and a multifunctional buffer hole-injection layer, in which high EQE (≈24%) current efficiency (≈73 cd A(-1) ) are demonstrated. High-efficiency red-emitting blue-emitting devices also fabricated this manner.
We have achieved high-efficiency polycrystalline perovskite light-emitting diodes (PeLEDs) based on formamidinium (FA) and cesium (Cs) mixed cations without quantum dot synthesis. Uniform single-phase FA1–xCsxPbBr3 films were fabricated by one-step formation with various FA:Cs molar proportions; then the influences of chemical composition film morphology, crystal structure, photoluminescence (PL), electroluminescence (EL) systematically investigated. Incorporation Cs+ in FAPbBr3...
Abstract Making small nanograins in polycrystalline organic–inorganic halide perovskite (OIHP) films is critical to improving the luminescent efficiency light‐emitting diodes (PeLEDs). 3D OIHPs have fundamental limitations related exciton binding energy and diffusion length. At same time, passivating defects at grain boundaries also when size becomes smaller. Molecular additives can be incorporated shield suppress boundaries; however, unevenly distributed molecular cause imbalanced charge...
Individual electron spins in solids are promising candidates for quantum science and technology, where bottom-up assembly of a device with atomically precise couplings has long been envisioned. Here, we realized atom-by-atom construction, coherent operations, readout coupled electron-spin qubits using scanning tunneling microscope. To enable the control “remote” that outside tunnel junction, complemented each spin local magnetic field gradient from nearby single-atom magnet. Readout was...
A unique implementation of an organic image detector using resistive photo-switchable pixels is presented. This photo-switch comprises the vertical integration photodiode and switching memory element. The photodiodes act as a photosensitive element while elements simultaneously store detected light information.
Abstract Organic–inorganic hybrid perovskites (OHPs) are promising emitters for light‐emitting diodes (LEDs) due to the high color purity, low cost, and simple synthesis. However, electroluminescent efficiency of polycrystalline OHP LEDs (PeLEDs) is often limited by poor surface morphology, small exciton binding energy, long diffusion length large‐grain films caused uncontrolled crystallization. Here, crystallization methylammonium lead bromide (MAPbBr 3 ) finely controlled using a polar...
Control of single electron spins constitutes one the most promising platforms for spintronics, quantum sensing, and information processing. Utilizing molecular magnets as their hosts establishes an interesting framework since structure is highly flexible chemistry-based large-scale synthesis directly provides a way toward scalability. Here, we demonstrate coherent spin manipulation molecules on surface, which control individually using scanning tunneling microscope in combination with...
On-fabrication solid-state N-doping of graphene is developed using a Zonyl-added ZnO layer on surface. Inverted organic solar cells based the cathode and exhibit power conversion efficiency 7.5%—a high-record single-junction with electrodes. For first time 100% respect to ITO achieved. As service our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed may be re-organized for online delivery, but not copy-edited or typeset....
Coherent control of individual atomic and molecular spins on surfaces has recently been demonstrated by using electron spin resonance (ESR) in a scanning tunneling microscope (STM). Here, combined experimental modeling study the ESR single hydrogenated Ti atom that is exchange-coupled to Fe adatom positioned 0.6-0.8 nm away means manipulation presented. Continuous wave pulsed show Rabi rate with two contributions, one from tip other Fe, whose interactions are modulated radio-frequency...
Motivated by recent developments in measurements of electron spin resonances individual atoms and molecules with a scanning tunneling microscope (ESR-STM), we study transport through an impurity under periodic driving as function the parameters model junction. The consists single-orbital quantum connected to two electrodes via time-dependent hopping terms. terms are treated at lowest order perturbation theory recover Lindblad-like master equation transport. As experiment, ESR-STM signal is...
Single atom magnets offer the possibility of magnetic information storage in most fundamental unit matter. Identifying parameters that control stability their states is crucial to design novel quantum with tailored properties. Here, we use X-ray absorption spectroscopy show electronic configuration dysprosium atoms on MgO(100) thin films can be tuned by proximity metal Ag(100) substrate onto which MgO are grown. Increasing thickness from 2.5 9 monolayers induces a change 4f9 4f10. Hysteresis...