A5018452714- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Nanocluster Synthesis and Applications
- ZnO doping and properties
- Semiconductor Quantum Structures and Devices
- Organic Light-Emitting Diodes Research
- Aeroelasticity and Vibration Control
- Advanced Aircraft Design and Technologies
- Molecular Junctions and Nanostructures
- Conducting polymers and applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Organic Electronics and Photovoltaics
- Advanced biosensing and bioanalysis techniques
- Polymer Surface Interaction Studies
- Advanced Photocatalysis Techniques
- Copper-based nanomaterials and applications
- Composite Structure Analysis and Optimization
- Nanowire Synthesis and Applications
- Nanomaterials and Printing Technologies
- Innovative Microfluidic and Catalytic Techniques Innovation
- Aerospace Engineering and Control Systems
- Photonic Crystals and Applications
- Rocket and propulsion systems research
- Semiconductor materials and interfaces
Sungkyunkwan University
2003-2025
Los Alamos National Laboratory
2014-2022
Soonchunhyang University
2020-2021
MIT-Harvard Center for Ultracold Atoms
2020
Suwon Research Institute
2019-2020
Government of the Republic of Korea
2020
Korea University
2020
Ajou University
2018-2019
University of New Mexico
2017
Seoul National University
2009-2016
We report highly bright and efficient inverted structure quantum dot (QD) based light-emitting diodes (QLEDs) by using solution-processed ZnO nanoparticles as the electron injection/transport layer optimizing energy levels with organic hole transport layer. have successfully demonstrated red, green, blue QLEDs showing maximum luminances up to 23,040, 218,800, 2250 cd/m(2), external efficiencies of 7.3, 5.8, 1.7%, respectively. It is also noticeable that they showed turn-on voltages low...
Development of light-emitting diodes (LEDs) based on colloidal quantum dots is driven by attractive properties these fluorophores such as spectrally narrow, tunable emission and facile processibility via solution-based methods. A current obstacle towards improved LED performance an incomplete understanding the roles extrinsic factors, non-radiative recombination at surface defects, versus intrinsic processes, multicarrier Auger or electron-hole separation due to applied electric field. Here...
We demonstrate bright, efficient, and environmentally benign InP quantum dot (QD)-based light-emitting diodes (QLEDs) through the direct charge carrier injection into QDs efficient radiative exciton recombination within QDs. The formation is facilitated by an adoption of a solution-processed, thin conjugated polyelectrolyte layer, which reduces electron barrier between cathode via vacuum level shift promotes balance these excitons enabled in structurally engineered InP@ZnSeS heterostructured...
CdSe/Zn1-X CdX S core/shell heterostructured quantum dots (QDs) with varying shell thicknesses are studied as the active material in a series of electroluminescent devices. "Giant" QDs (e.g., CdSe core radius 2 nm and Zn1-X thickness 6.3 nm) demonstrate high device efficiency (peak EQE = 7.4%) record-high brightness (>100 000 cd m(-2) ) deep-red emission, along improved stability.
Utilizing the reactivity difference between TOPSe and TOPS, we synthesized InP@ZnSeS QDs with composition gradient in a radial direction where ZnSe alleviated lattice strain ZnS protected from degradation so that achieved high QE photo/chemical stability. In terms of systematic investigation on relationship shell nanostructure QD stability, demonstrated thick shells exhibited much enhanced stability against under UV irradiation, ligand exchange, or rigorous purification. This is attributed...
Colloidal semiconductor quantum dots (QDs) are a highly promising materials platform for implementing solution-processable light-emitting diodes (LEDs). They combine high photostability of traditional inorganic semiconductors with chemical flexibility molecular systems, which makes them well-suited large-area applications such as television screens, solid-state lighting, and outdoor signage. Additional beneficial features include size-controlled emission wavelengths, narrow bandwidths,...
Bright, low-voltage driven colloidal quantum dot (QD)-based white light-emitting devices (LEDs) with practicable device performances are enabled by the direct exciton formation within quantum-dot active layers in a hybrid structure. Detailed characterization reveals that white-QLEDs can be rationalized as parallel circuit, which different QDs connected through same set of electrically common organic and inorganic charge transport layers. Nanocrystal dots (QDs) have been considered most...
Quantum dot light-emitting diodes (QLEDs) are one of the most promising candidates for next-generation displays and lighting sources, but they barely used because vulnerability to electrical thermal stresses precludes high brightness, efficiency, stability at current density (J) regimes. Here, bright stable QLEDs on a Si substrate demonstrated, expanding their potential application boundary over present art. First, tailored interface is granted quantum dots, maximizing yield mitigating...
Nanocrystal quantum dots (QDs) are attractive materials for applications as laser media because of their bright, size-tunable emission and the flexibility afforded by colloidal synthesis. Nonradiative Auger recombination, however, hampers optical amplification in QDs rapidly depleting population gain-active multiexciton states. In order to elucidate role recombination QD lasing isolate its influence from other factors that might affect gain, we study two types CdSe/CdS core/shell with same...
Abstract Establishing multi-colour patterning technology for colloidal quantum dots is critical realising high-resolution displays based on the material. Here, we report a solution-based processing method to form patterns of using light-driven ligand crosslinker, ethane-1,2-diyl bis(4-azido-2,3,5,6-tetrafluorobenzoate). The crosslinker with two azide end groups can interlock ligands neighbouring upon exposure UV, yielding chemically robust dot films. Exploiting crosslinking process,...
Luminescent solar concentrators (LSCs) can be utilized as both large-area collectors of radiation supplementing traditional photovoltaic cells well semitransparent "solar windows" that provide a desired degree shading and simultaneously serve power-generation units. An important characteristic an LSC is concentration factor (C) thought coefficient effective enlargement (or contraction) the area cell when it coupled to LSC. Here we use analytical numerical Monte Carlo modeling in addition...
A systematic analysis of the exciton-recombination zone within all-quantum dot (QD) multilayer films prepared by a layer-by-layer assembly method was made, using sensing QD layers in QD-based light-emitting diodes (QLEDs). Large area practical multicolored colloidal QLEDs were also demonstrated patterning and placing variously colored QDs (red, orange, yellow-green, green) zone.
Advance in wet chemistry enables the sophisticated design of nanocrystal quantum dots (QDs) and allows unprecedented color purity brightness, promising their useful applications a variety light-emitting applications. A representative example is core/shell heterostructures, which charge carriers are effectively decoupled from structural artifacts to generate photons efficiently. Despite development widely accepted synthetic protocols for Cd- or Pb-based QDs, progress heterostructuring...
Quantum dot-based light emitting diodes have extensively been investigated over the past two decades in order to utilize high color purity and photophysical stability of quantum dots. In this review, progresses on preparation dots, structural design electroluminescence devices using printing processes for full-color dot display will be discussed. The obstacles originating from use heavy metals, large hole injection barrier, imperfect pixilation limited practical applications devices. It is...
Abstract Realization of electrically pumped lasing with solution processable materials will have a revolutionary impact on many disciplines including photonics, chemical sensing, and medical diagnostics. Due to readily tunable, size-controlled emission wavelengths, colloidal semiconductor quantum dots (QDs) are attractive for attaining this goal. Here we use specially engineered QDs demonstrate devices that operate as both light emitting diode (LED) an optically laser. These structures...
Thin-film ultraviolet (UV) light-emitting diodes (LEDs) with emission wavelengths below 400 nm are emerging as promising light sources for various purposes, from our daily lives to industrial applications. However, current thin-film UV-emitting devices radiate not only UV but also visible light. Here, we introduce genuine colloidal nanocrystal quantum dot (NQD) LEDs (QLEDs) using precisely controlled NQDs consisting of a 2.5-nm-sized CdZnS ternary core and ZnS shell. The effective size is...
Auger recombination is a nonradiative three-particle process wherein the electron-hole energy dissipates as kinetic of third carrier. decay enhanced in quantum-dot (QD) forms semiconductor materials compared to their bulk counterparts. Because this detrimental many prospective applications QDs, development effective approaches for suppressing has been an important goal QD field. One such approach involves "smoothing" confinement potential, which suppresses intraband transition involved...
Quantum dot/conducting polymer hybrid films are used to prepare light-emitting diodes (LEDs). The (CdSe@ZnS quantum dots excellently dispersed in a conducting matrix, see figure) readily prepared by various solution-based processes and also easily micropatterned. LEDs exhibit turn-on voltage of 4 V, an external efficiency greater than 1.5%, almost pure-green quantum-dot electroluminescence.
We report scalable controlled synthesis of CdSe tetrapods with high morphological uniformity based on the continuous precursor injection (CPI) approach halide ligands. The CPI involves successive precursors into seed solution at a rate so that reaction condition remains in kinetic growth regime. To initiate successful development tetrapod structure, amount ligands are added during reaction, which triggered formation wurtzite arms {111}-facets zincblende seeds. phase is responsible for...
Application of colloidal semiconductor quantum dots (QDs) in optical and optoelectronic devices is often complicated by unintentional generation extra charges, which opens fast nonradiative Auger recombination pathways whereby the energy an exciton quickly transferred to carrier(s) ultimately dissipated as heat. Previous studies have primarily focused on neutral and, more recently, negatively charged multicarrier states. dynamics positively species remains poorly explored due difficulties...