정선호 교수

Ga doping in indium zinc oxide (IZO)-based amorphous-oxide semiconductors (AOSs) promotes the formation of oxide-lattice structures with oxygen vacancies at low annealing temperatures, which is essential for acceptable thin-film-transistor performance (see figure). The mobility dependence on annealing temperature and AOS composition are analyzed and the chemical role of Ga is clarified, as required for solution-processed, low-temperature-annealed AOSs. Detailed facts of importance to specialist

Abstract With the aim of preparing a high performance conductive ink, we sought to control the surface chemistry of Cu nanoparticles so as to minimize surface oxidation. Specifically, the surface oxide layer on Cu nanoparticles synthesized in ambient atmosphere was minimized by adjusting the molecular weight of poly( N ‐vinylpyrrolidone) capping molecules, as confirmed by high resolution transmission electron microscopy and X‐ray photoelectron spectroscopy analyses. In addition, we demonstrate t

High-performance, solution-processable semiconductors have drawn significant attention for use in low-cost, functional electronic applications. Metal oxide semiconductors are the most promising building blocks for high performance electronic devices because of their electrical properties and solution-processability. However, the major impediment for metal oxide semiconductors is that the electrical properties applicable to electronic devices are activated by chemical/physical structural evolutio

With the aim of inkjet printing highly conductive and well-defined Cu features on plastic substrates, aqueous based Cu ink is prepared for the first time using water-soluble Cu nanoparticles with a very thin surface oxide layer. Owing to the specific properties, high surface tension and low boiling point, of water, the aqueous based Cu ink endows a variety of advantages over conventional Cu inks based on organic solvents in printing narrow conductive patterns without irregular morphologies. It i

A zinc tin oxide (ZTO) semiconductor layer for thin-film transistor was fabricated using solution-processable sol−gel material. To obtain semiconductor characteristics, ZTO gels should be annealed such that salts and organic components in the ZTO layer undergo complete decomposition. The thermal behavior of ZTO precursor materials was investigated, and the electrical performances of solution-processed transistors were analyzed as a function of the annealing temperature of the ZTO semiconductor l

A high-performance piezoelectric nanocomposite generator (PNG) based on chemically reinforced composites is demonstrated by incorporating amine-functionalized lead zirconate titanate (PZT-NH₂) nanoparticles into a polymer matrix.

Air-stable, surface-oxide free Cu nanoparticles are, for the first time, synthesized by surrounding completely the Cu surface with oleic acid incorporated as a capping molecule. XPS analysis, in conjunction with TEM analysis, revealed that the oleic acid is chemisorbed to the Cu surface via a chemical interaction wherein a monodentate bond is included, without leaving behind free (non-interacting) oleic acid, thereby providing complete surface protection against oxidation. By eliminating the sur

Although high dielectric constant (k) oxide thin film has been considered as a key element for high performance and low-voltage driven thin-film transistors (TFTs), there are no solution processable high-k oxide dielectrics that satisfy the stringent requirements of low-temperature processability, mechanical flexibility, and good TFT performance. Here, we demonstrate that the incorporation of a zirconium component that has strong bonding to oxygen enables a significant reduction in the processin

Multiphase CuInSe2 (CISe) nanoparticles including the CuSe phase are synthesized by the microwave-assisted solvothermal method. Without additional processing, multiphase CISe nanoparticles facilitate the solution-processed CISe absorber layer with a dense microstructure, large grains, high crystallinity, and composition controllability, which are essential for acceptable thin-film solar cell performance. The high performance, solution-processed CISe solar cell, with a conversion efficiency of 8.

Sol–gel-derived oxide semiconductors annealed at a low temperature have been of great interest recently in various thin-film transistor (TFT) applications. However, studies on the influence of metal salt precursor on sol–gel-derived oxide semiconductor annealed at a low temperature have not yet been reported. In this study, the impact of metal salt precursor on the chemical structure evolution of Ga-doped In2O3 (IGO) semiconductor and electrical performance of thin-film transistors with a corres

Recently, organometal halide perovskite (OMHP)‐based solar cells have been regarded as one of the most promising technologies in the research field of renewable energy applications. Along with successful demonstrations of high power conversion efficiencies (PCEs), various characteristic strategies for fabricating functional OMHP‐based solar cells have been exploited to facilitate both their practical applicability and industrial suitability. As a part of such efforts, unconventional transparent

We report the previously unrecognized co-solvent, formamide (FA), which can comprehensively improve both the device performance and bias stability of metal salt-derived, solution-processed In–Ga–Zn–O (IGZO) TFTs. By incorporating FA in IGZO precursor solutions, the chemical structures are tailored adequately for reducing the content of hydroxide and encouraging the oxygen vacancy formation, which has not been fulfilled in conventional chemical/physical approaches. Owing to such distinct chemical

We synthesized silver nanoparticles via chemical reduction method in aqueous medium and poly(acrylic acid) sodium salt (PAA), a kind of anionic polyelectrolyte, was used as a capping agent as well as a dispersant. Owing to the electrosteric repulsion characteristic of PAA, the prepared aqueous Ag ink exhibited a remarkable dispersion stability, which was confirmed by sedimentation test, zeta-potential measurement, and rheological analysis. We fabricated narrow conductive features onto the polyim

A novel inkjet printing procedure based on a well-dispersed aqueous Ag ink and a molecular adhesive layer is presented for the fabrication of highly conductive and narrow patterns exhibiting the excellent adhesion property on a glass substrate. The aqueous dispersion of silver nanoparticles is synthesized via a chemical reduction method in the aqueous medium in which an anionic polyelectrolyte is incorporated as both a capping agent and a dispersant. Owing to the electrosteric repulsion characte

Highly flexible, rollable, printable Ag conductive features are generated on PET and paper substrates through instant continuous photonic sintering for olate-terminated Ag nanoparticles.