A5100454636- Ferroelectric and Piezoelectric Materials
- Acoustic Wave Resonator Technologies
- Advanced Sensor and Energy Harvesting Materials
- Multiferroics and related materials
- Semiconductor materials and devices
- Block Copolymer Self-Assembly
- Dielectric materials and actuators
- Electronic and Structural Properties of Oxides
- Quantum Dots Synthesis And Properties
- Innovative Energy Harvesting Technologies
- Ferroelectric and Negative Capacitance Devices
- Conducting polymers and applications
- Microwave Dielectric Ceramics Synthesis
- Catalytic Processes in Materials Science
- Chalcogenide Semiconductor Thin Films
- Advanced Polymer Synthesis and Characterization
- Electrocatalysts for Energy Conversion
- Nuclear Materials and Properties
- Force Microscopy Techniques and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Hydrogen embrittlement and corrosion behaviors in metals
- Thin-Film Transistor Technologies
- Advanced Memory and Neural Computing
- Polymer Surface Interaction Studies
- Copper Interconnects and Reliability
University of Illinois Urbana-Champaign
2013-2025
Samsung (South Korea)
2003-2025
Korea Institute of Materials Science
2019-2024
Sungkyunkwan University
2012-2024
Brown University
2015-2024
Korea University
2016-2024
Sangmyung University
2024
Seoul Semiconductor (South Korea)
2024
Gwangju Institute of Science and Technology
2018-2023
Korea Advanced Institute of Science and Technology
2019-2023
We fabricated CZTSSe thin films using optimized SLG-Mo/Zn/Cu/Sn (MZCT) as a stacked structure and described the phenomenon of Zn elemental volatilization MZCT structure.
Abstract In the past two decades, mechanical energy harvesting technologies have been developed in various ways to support or power small‐scale electronics. Nevertheless, strategy for enhancing current and charge performance of flexible piezoelectric harvesters using a simple cost‐effective process is still challenging issue. Herein, 1D–3D (1‐3) fully nanocomposite perovskite BaTiO 3 (BT) nanowire (NW)‐employed poly(vinylidene fluoride‐ co ‐trifluoroethylene) (P(VDF‐TrFE)) high‐performance...
The self-assembly of triblock copolymers poly(ethylene oxide-b-methyl methacrylate-b-styrene) (PEO-b-PMMA-b-PS), where PS is the major component and PMMA PEO are minor components, provides a robust route to highly ordered, nanoporous arrays with cylindrical pores 10−15 nm that show promise in block copolymer lithography. These ABC were synthesized by controlled living radical polymerization, after solvent annealing, thin films showing defect-free microdomains obtained. key successful...
We investigated domain kinetics by measuring the polarization switching behaviors of (111)-preferred polycrystalline $\mathrm{Pb}(\mathrm{Zr},\mathrm{Ti}){\mathrm{O}}_{3}$ films, which are widely used in ferroelectric memories. Their at various electric fields and temperatures could be explained assuming Lorentzian distribution logarithmic domain-switching times. suggested that local field variation due to dipole defects pinning sites explain distribution.
A new way to control the characteristic dimensions of morphologies in polymer systems is demonstrated with a mixture block copolymer and small amount homopolymer. Controlled solvent annealing casting produces long-range order over large areas for blends (see Figure), through selective removal homopolymer, almost defect-free arrays nanoscopic holes are produced film.
In this study, a stochastic method for the microstructural reconstruction of catalyst layers in proton exchange membrane (PEM) fuel cells is presented, and empirical expressions effective transport coefficients reconstructed are obtained use macroscale cell simulations. The proposed based on simulated annealing, where problem formulated as an optimization problem. By exploiting information from manufacturing process adopting trial statistical function, performs three-phase reconstruction,...
We show that acetone-derived graphene coating can effectively enhance the corrosion efficiency of copper (Cu) in a seawater environment (0.5–0.6 M (∼3.0–3.5%) sodium chloride). By applying drop acetone (∼20 μl cm−2) on Cu surfaces, rapid thermal annealing allows facile and synthesis films surfaces with monolayer coverage almost close to ∼100%. Under optimal growth conditions, is found have relatively high crystallinity, comparable common grown by chemical vapor deposition. The resulting...
<i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">31</sub> and xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> mode microelectromechanical systems piezoelectric energy harvesters (PEHs) were fabricated compared to investigate their output powers converted from vibration. Both types of devices have the same dimensions in a cantilever structure aim effectively couple vibration ambient...
Abstract In this paper, we demonstrated the feasibility of Aerosol Deposition (AD) method which can be adapted as a future fabrication process for flexible electronic devices. On basis method’s noticeable advantages such room-temperature processing, suitability mass production, wide material selectivity, and direct on substrate, fabricated evaluated conductive bridge random access memory (CBRAM) to confirm method. The CBRAM was by AD-method, novel film formation mechanism observed analyzed....
In spite of extremely high piezoelectric and pyroelectric coefficients, there are few reports on flexible ferroelectric perovskite film based nanogenerators (NGs). Here, we report the successful growth a Pb(Zr0.52Ti0.48)O3 (PZT) its application to hybrid piezoelectric-pyroelectric NG. A highly Ni–Cr metal foil substrate with conductive LaNiO3 bottom electrode enables PZT having (140 pC/N) (50 nC/cm2K) coefficients at room temperature. The PZT-based NG effectively scavenges mechanical...
Lead-free Mn-doped (K0.5, Na0.5)NbO3 (KNN) thin films were fabricated by the chemical solution deposition method. The addition of small concentration Mn dopant effectively reduced leakage current density and enhanced piezoelectric properties films. 0.5 mol. % KNN film showed lowest value ∼10-7 A/cm2 at 10 V compared to with other doping concentrations d33 e31 coefficients this ∼90 pm/V −8.5 C/m2, respectively. maximum power lead-free film-based vibrational energy harvesting device 3.62 μW...
Cooling environments are a pervasive need in our society, with conventional air conditioners being the most popular approach. However, rely heavily on electricity and Freon, chemical that depletes ozone contributes to greenhouse gas effects. To address this issue, passive daytime radiative coolers (PDRCs) have been proposed achieve cooling by simultaneously reflecting sunlight allowing internal heat escape without electricity. Despite their potential, high-performance PDRCs composed of thick...
The directed self-assembly of diblock copolymers offers unique routes for the design and fabrication well-ordered arrays nanoscopic structures. However, generating with long-range order few defects has been a difficult goal to achieve without extended thermal annealing processes. Here, simple, one-step route, based on flow solution within droplet pinned surface coupled solvent evaporation, is shown where highly oriented, ordered cylindrical domains block copolymer can be produced over large...
Ion complexation within cylinder-forming block copolymer thin films was found to affect the ordering process of during solvent annealing, significantly enhancing long-range positional order. Small amounts alkali halide or metal salts were added PS-b-PEO, on order a few ions per chain, where salt complexed with PEO block. The orientation cylindrical microdomains strongly depended concentration and ability complex PEO. shows large flexibility in choice used, including gold cobalt salts,...
The preparation of anisotropic colloidal particles by a simple yet versatile temperature-controlled swelling process is described. resulting polymeric feature surface dimple, the size and shape which were determined amount oil captured in interfacial tension between three phases: polystyrene (PS), decane, suspending medium. Following removal free or physically adsorbed surfactant from swollen particles, hydrophobic dimples produced upon evaporation phase. We demonstrate spontaneous assembly...
We prepared indium zinc oxide (IZO) semiconductors for low temperature solution-processed thin-film transistors (TFTs). The sol–gel derived IZO films, annealed at , are uniform and have smooth surface morphology (root-mean-square roughness of 0.27 nm). Both the composition film thickness need to be optimized high performance TFTs. With In/Zn equal 50/50 in mol percent, TFTs with a 10 nm exhibited best clear switching behavior (on/off current ratio ) output characteristics (drain ),...
Abstract The utilization of ferromagnetic (FM) materials in thermoelectric devices allows one to have a simpler structure and/or independent control electric and thermal conductivities, which may further remove obstacles for this technology be realized. thermoelectricity FM/non-magnet (NM) heterostructures using an optical heating source is studied as function NM number multilayers. It observed that the overall signal those structures contributed by spin Seebeck effect anomalous Nernst (ANE)...
Flexible high energy density capacitors were fabricated by depositing 6 mol. % La-doped anti-ferroelectric PbZrO3 thin films using chemical solution deposition on ultra-thin metal foil substrates. The integration of a LaNiO3 buffer layer the flexible austenitic substrate resulted in substantial improvements microstructure uniformity and film capacitors. recoverable loss 15.2 ± 0.2 J/cm3 4.8 at 1 MV/cm, respectively. showed no noticeable degradation ferroelectric hysteresis behavior storage...
Environmentally benign lead-free ferroelectric (K0.5,Na0.5)(Mn0.005,Nb0.995)O3 (KNMN) thin film capacitors with a small concentration of BiFeO3 (BF) dopant were prepared by cost effective chemical solution deposition method for high energy density storage device applications. 6 mol. % BF-doped KNMN films showed very slim hysteresis loops maximum and near-zero remanent polarization values due to phase transition from the orthorhombic structure pseudo-cubic structure. Increasing electric field...