Jong-Hak Kim

We report remarkably high energy conversion efficiency (4.5% at 100 mW cm(-2)) of a dye-sensitized solar cell in the solid state, using composite polymer electrolytes containing fumed silica nanoparticles.

Transition metal based layered double hydroxides are important energy storage materials. The overall performances of the electrodes are dependent on conductivity, crystallinity, morphology, and surface area.

Recently, the WO 3 /BiVO 4 heterojunction has shown promising photoelectrochemical (PEC) water splitting activity based on its charge transfer and light absorption capability, and notable enhancement of the photocurrent has been achieved via morphological modification of WO 3 . We developed a graft copolymer-assisted protocol for the synthesis of WO 3 mesoporous thin films on a transparent conducting electrode, wherein the particle size, particle shape, and thickness of the WO 3 layer were contr

Propylene solubility is almost 2-fold higher in 1:1 poly(2-ethyl-2-oxazoline) (POZ):AgBF 4 or poly(vinyl pyrrolidone) (PVP):AgBF 4 than in 1:1 POZ:AgCF 3 SO 3 or 1:1 PVP:AgCF 3 SO 3, according to our previous work. It is confirmed in this paper that the C C stretching band of propylene coordinated with silver cations in 1:1 PVP:AgBF 4 is about 2-fold more intense than that in 1:1 PVP:AgCF 3 SO 3 . This difference in solubility is investigated here in terms of the differences in the interactions

A facile and effective method to prepare hierarchical pine tree‐like TiO 2 nanotube (PTT) arrays with an anatase phase directly grown on a transparent conducting oxide substrate via a one‐step hydrothermal reaction. The PTT arrays consist of a vertically oriented long nanotube (NT) stem and a large number of short nanorod (NR) branches. Various PTT morphologies are obtained by adjusting the water/diethylene glycol ratio. The diameter of the NTs and the size of the NR branches decreases from 300

Randomly microphase-separated graft copolymers have been self-reorganized so as to exhibit a micellar structure with excellent connectivity upon tuning the solvent affinity. These copolymers are used as a structure-directing agent for organized mesoporous TiO(2) films with no grain boundaries, leading to enhanced solar conversion efficiency of dye-sensitized solar cells.

Titania (TiO2) nanoparticles were surface-modified via atom transfer radical polymerization (ATRP) with hydrophilic poly(oxyethylene) methacrylate (POEM), which can coordinate to the TiO2 precursor, titanium(IV) isopropoxide (TTIP). Following application of a sol–gel process and calcination at 450 °C, TiO2 nanospheres with hierarchical pores were generated, as confirmed by the shifting of conduction bands in TiO2 using UV-visible spectroscopy and X-ray photoelectron spectroscopy (XPS). The parti

This study reports a low‐temperature processable, resistive switching (RS) device based on an inorganic–organic hybrid perovskite, i.e., methylammonium lead iodide (CH 3 NH 3 PbI 3 or MAPbI 3 ) via a fast deposition–crystallization method, as the multifunctional insulator layer to form metal/insulator/metal structure in which Al and p + ‐Si wafer are used as the top and the bottom metal electrodes, respectively. The MAPbI 3 ‐RS device shows acceptable RS characteristics with a switching window o