A5056662009- Conducting polymers and applications
- Organic Electronics and Photovoltaics
- Perovskite Materials and Applications
- Quantum Dots Synthesis And Properties
- Advanced Photocatalysis Techniques
- Chalcogenide Semiconductor Thin Films
- TiO2 Photocatalysis and Solar Cells
- Molecular Junctions and Nanostructures
- Thin-Film Transistor Technologies
- Advanced Sensor and Energy Harvesting Materials
- Electrochemical sensors and biosensors
- Supercapacitor Materials and Fabrication
- Organic Light-Emitting Diodes Research
- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Luminescence and Fluorescent Materials
- Advanced Thermoelectric Materials and Devices
- Electrocatalysts for Energy Conversion
- Diamond and Carbon-based Materials Research
- Advanced Nanomaterials in Catalysis
- Force Microscopy Techniques and Applications
- Gas Sensing Nanomaterials and Sensors
- Electrochemical Analysis and Applications
- Electrospun Nanofibers in Biomedical Applications
- Advanced battery technologies research
Ulsan National Institute of Science and Technology
2019-2025
Government of the Republic of Korea
2016-2021
Kookmin University
2011-2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2013
Korea Advanced Institute of Science and Technology
2013
Structure et Propriétés d'Architectures Moléculaires
2013
Université Grenoble Alpes
2013
Centre National de la Recherche Scientifique
2013
CEA Grenoble
2013
Institut Nanosciences et Cryogénie
2013
By trapping molecules between two gold electrodes with a temperature difference across them, the junction Seebeck coefficients of 1,4-benzenedithiol (BDT), 4,4′-dibenzenedithiol, and 4,4′′-tribenzenedithiol in contact were measured at room to be +8.7 ± 2.1 microvolts per kelvin (μV/K), +12.9 2.2 μV/K, +14.2 3.2 respectively (where error is full width half maximum statistical distributions). The positive sign unambiguously indicates p-type (hole) conduction these heterojunctions, whereas Au...
Employing graphene as an intracavity passive power modulating element, we demonstrate the efficient laser pulsation in high pulse-energy regime with evanescent field interaction between propagating light and layer. Graphene is prepared by solution based reduction of oxide, dispersed homogeneously into water for spray onto all-fiber substrate, side-polished fiber. With up to 21.41 dBm, ensure robust high-energy operation without any thermal damage graphene. Resultant output pulses have center...
We report the preparation of free-standing flexible conductive reduced graphene oxide/Nafion (RGON) hybrid films by a solution chemistry that utilizes self-assembly and directional convective-assembly. The hydrophobic backbone Nafion provided well-defined integrated structures, on micro- macroscales, for construction materials through self-assembly, while hydrophilic sulfonate groups enabled highly stable dispersibility (∼0.5 mg/mL) long-term stability (2 months) graphene. geometrically...
Abstract Herein, this study reports high‐efficiency, low‐temperature ZnO based planar perovskite solar cells (PSCs) with state‐of‐the‐art performance. They are achieved via a strategy that combines dual‐functional self‐assembled monolayer (SAM) modification of electron accepting layers (EALs) sequential deposition active layers. The SAMs, constructed from newly synthesized molecules high dipole moments, act both as excellent surface wetting control and electric for ZnO‐EALs. insertion SAMs...
We report intrinsically self-healable and stretchable ionic thermoelectric materials, which exhibits excellent figure-of-merit (1.04), with remarkable stretchability (~750%) autonomous self-healability.
Thermopower measurements offer an alternative transport measurement that can characterize the dominant orbital and is independent of number molecules in junction. This method now used to explore effect chemical structure on electronic charge transport. We interrogate junctions, using a modified scanning tunneling microscope break junction technique, where: (i) 1,4-benzenedithiol (BDT) molecule has been by addition electron-withdrawing or -donating groups such as fluorine, chlorine, methyl...
Water-soluble, polyelectrolyte-grafted multiwalled carbon nanotubes (MWCNTs), MWCNT-g-PSSNa, were synthesized using a "grafting to" route. MWCNT-g-PSSNa thin films fabricated by an electrostatic spray (e-spray) technique used as the counter electrode (CE) for dye-sensitized solar cells (DSSCs). The e-sprayed thin-film-based CEs (MWCNT-CE) uniform over large area, and well-exfoliated MWCNTs formed highly interconnected network structures. electrochemical catalytic activity of MWCNT-CE at...
In this report, dye-sensitized solar cells (DSSCs) with high energy conversion efficiencies were fabricated using TiO2 nanorods electrospun from a solution mixture of titanium n-propoxide and poly(vinyl acetate) in dimethyl formamide. Investigation the charge transport characteristics unique type DSSC disclosed that efficiency DSSCs was enhanced by optimizing nanorod morphology to facilitate transport. Our have an intrinsically higher sensitizer loading capability than conventional...
We present a combined experimental and computational study that probes the thermoelectric electrical transport properties of molecular junctions. Experiments were performed on junctions created by trapping aromatic molecules between gold electrodes. The end groups (-SH, -NC) systematically varied to effect contact coupling strength chemistry. When molecule with one electrodes was reduced switching terminal chemistry from -SH -H, conductance decreased an order magnitude, whereas thermopower...
Abstract Polymer solar cells (PSCs) are fabricated using a novel film deposition method, the electrostatic spray (e‐spray) technique. Stable atomization and uniform of polymer blend by e‐spray achieved manipulating solution concentration, solvent composition, electric field. The performance PSCs is primarily influenced inherent morphology e‐sprayed polymer‐blend active layers, which significantly different from that conventional films formed spin‐coating (SC) method. intrinsically...
We report a simple method to prepare hierarchically structured TiO(2) spheres (HS-TiO(2)), using an electrostatic spray technique, that are utilized for photoelectrodes of highly efficient dye-sensitized solar cells (DSSCs). This has advantage remove the synthesis steps in conventional sol-gel form nano-sized nanoclusters. The fine dispersion commercially available nanocrystalline particles (P25, Degussa) EtOH without surfactants and additives is electro-sprayed directly onto fluorine-dopoed...
Colloidal‐quantum‐dot (CQD) photovoltaic devices are promising candidates for low‐cost power sources owing to their low‐temperature solution processability and bandgap tunability. A conversion efficiency (PCE) of >10% is achieved these devices; however, there several remaining obstacles commercialization, including high energy loss due surface trap states the complexity multiple‐step CQD‐layer‐deposition process. Herein, high‐efficiency prepared with CQD‐ink using a...
We demonstrate deformation-suppressed optical deposition of graphene onto an fiber by forming a graphene/polyvinyl acetate (PVAc) composite for ultrafast nonlinear photonics. With pure graphene, its operation threshold is elevated the that cannot guarantee intact two-dimensional nanoshape graphene. The role PVAc provides immunity to against deleterious degradation morphology and nonlinearity elucidated via electron microscope analysis, Raman characterization, realizing passive mode-locking...
High-efficiency colloidal quantum dot photovoltaic devices (CQDPVs) are achieved by improving the interfacial charge extraction via chemical modification of PbS-CQD/ZnO heterojunctions. Simple treatment heterojunctions using a modifier, 1,2-ethanedithiol, effectively reduces interband trap sites ZnO nanoparticles (ZnO-np) passivation notorious intrinsic oxygen-deficient defects. As result, bimolecular recombinations between (i) trapped electrons in ZnO-np layers and holes CQD (ii)...
Abstract A charge transport layer based on transition metal‐oxides prepared by an anhydrous sol–gel method normally requires high‐temperature annealing to achieve the desired quality. Although is not a difficult process in laboratory, it definitely simple mass production, such as roll‐to‐roll, because of inevitable long cooling step that follows. Therefore, development annealing‐free solution‐processable metal‐oxide essential for large‐scale commercialization. In this work, room‐temperature...
While perovskite solar cells (PSCs) have emerged as promising low-cost power generators, most reported high-performance PSCs employ electron transport layers (ETLs, mainly TiO2) treated at high temperatures (≥450 °C), which may eventually hinder the development of flexible PSCs. Meanwhile, low-temperature processed (L-PSCs) possessing performance levels comparable to those high-temperature has actively been reported. In this study, L-PSCs with improved long-term stability and negligible...
Abstract In most current state‐of‐the‐art perovskite solar cells (PSCs), high‐temperature (≈500 °C)‐sintered metal oxides are employed as electron‐transporting layers (ETLs). To lower the device processing temperature, development of low‐temperature‐processable ETL materials (such solution‐processed ZnO) has received growing attention. However, thus far, use ZnO is limited because reverse decomposition reaction that occurs at ZnO/perovskite interfaces significantly degrades charge collection...
Herein, we achieved, air-stable low-temperature processed PSC (L-PSC) using alkali-metal modified ZnO ETLs. Using a simple chemical modification method, the surface defects of were effectively passivated. As result, interfacial decomposition reactions suppressed, while raising Fermi energy level and enhancing electron mobility. The improved charge transfer internal electric field in developed L-PSC K (ZnO-K) exhibited an power conversion efficiency (PCE) 19.90% with negligible hysteresis,...
Solid-state-ligand-exchange free high-efficiency colloidal quantum dot solar cells were developed by direct coating of n-type and p-type inks.
Abstract Self‐healable and stretchable thermoelectric (TE) materials provide new possibilities for self‐powered flexible wearable devices to self‐repair mechanical damage. However, developing high‐performance with such desirable TE properties is a significant challenge. In this work, organic–inorganic ionic composites (OITCs) an unprecedently high figure of merit (ZT i = 3.74 at 80% relative humidity) robust simultaneous self‐healing stretching are reported. The OITCs developed by...
Abstract Solar hydrogen production is one of the ultimate technologies needed to realize a carbon-neutral, sustainable society. However, an energy-intensive water oxidation half-reaction together with poor performance conventional inorganic photocatalysts have been big hurdles for practical solar production. Here we present photoelectrochemical cell record high photocurrent density 19.8 mA cm −2 by utilizing high-performance organic–inorganic halide perovskite as panchromatic absorber and...