• Proceedings of the Optical Society of Korea Conference
• /
• 2004.07a
• /
• pp.206-207
• /
• 2004

• Journal of Integrative Natural Science
• /
• v.2 no.1
• /
• pp.50-53
• /
• 2009

New functionalized siloles have been synthesized and their optical characterizations are investigated. Silole unit has been interested, since silole has a unique optical and electronic properties. Here we report the synthesis of new type of photoluminescent silole. New siloles have been characterized by NMR, FTIR, and UV-vis absorption spectroscopy. Their optical characteristics have been also investigated using photoluminescence spectroscopy. Possible applications such as OLED and chemical sensors will be presented.

• Proceedings of the Optical Society of Korea Conference
• /
• 2005.02a
• /
• pp.282-283
• /
• 2005

• Journal of Integrative Natural Science
• /
• v.2 no.3
• /
• pp.194-197
• /
• 2009

Organometallic containing silole unit has been interested, since silole has a unique optical and electronic properties. The main goal of this work is to develop new selective sensors for organosilicon of 1-methyl-2,3,4,5-tetraphenyl-1H-silole and 1-methyl-1-(3-aminopropyl)-2,3,4,5-tetraphenylsilole based on new silole have been characterized by UV-vis absorption spectroscopy. their optical characteristics have been also investigate using photoluminescence spectroscopy.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.6
• /
• pp.229-233
• /
• 2005

Novel process was tried to obtain micro-porous ceramic body containing continuous pore channel. $MgAl_2O_4/MgO$ eutectic fibers and rods have been grown successfully by the micro-pulling-down method, and the microstructures and optical characterizations of grown crystals were performed. $MgAl_2O_4/MgO$ eutectic fibers of $0.3{\sim}1mm$ in diameter and about 500 mm in length, and the rods having 5 mm in diameter with approximately 60 mm in length have been grown with the $6{\sim}120mm/hr$ of growth speed. The eutectic fibers showed homogeneous microstructure in which MgO fiber aligned to the growth direction in the $MgAl_2O_4$ (spinel) matrix. The grown crystals looked semitransparency under naked eyes. Optical and orientational characterizations were performed. The second phase of MgO (periclase) was easily removed by selective etching with hydrochloric acid, and then porous bodies were obtained.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.12
• /
• pp.3834-3837
• /
• 2010

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2010.05a
• /
• pp.11.2-11.2
• /
• 2010

Photovoltaic devices are promising candidates as affordable and large-area renewable energy sources, which can replace the fossil-fuel-based resources. Especially, thin film solar cells have attracted increasing research attention, since they have a great advantage of low production cost. From the physical point of view, the photovoltaic devices can provide us interesting questions, how to enhance the light absorption and the carrier collection efficiency. A lot of approaches would be possible to address these issues. We have focused on two major topics relevant to photovoltaic device physics; (1) light management using surface plasmons and (2) junction characterizations aiming at proper interface engineering. Regarding the first topic, we have investigated the influences of Ag under-layer morphology on optical properties of ZnO thin films. The experimental results suggested that coupling between the surface plasmon polaritons at the ZnO/Ag interface and excitons in ZnO should play important roles in reflectivity of the ZnO/Ag thin films, which are widely used back reflector structures in thin film solar cells. For the second topic, we have carried out scanning probe microscopy studies of Schottky junctions consisting of photovoltaic materials. Such a research is very helpful to understand the correlation between the defects (e.g., grain boundaries) and local electrical properties. We will introduce some of the recent experimental results and discuss the physical significance.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.3
• /
• pp.377-389
• /
• 2022

The current global energy supply depends heavily on fossil fuels. This makes technology such as direct water splitting from harvesting solar energy in photoelectrochemical (PEC) systems potentially attractive due to its a promising route for environmentally benign hydrogen production. In this study, undoped and nickel-doped molybdenum oxide photoanodes (called photoanodes S₁ and S₂ respectively) were synthesized through electrodeposition by applying -1.377 V vs Ag/AgCl (3 M KCl) for 3 hours on an FTO-coated glass substrate immersed in molibdatecitrate aqueous solutions at pH 9. Scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used for microstructural and compositional characterizations of the photoanodes. In addition, the optical and photoelectrochemical characterizations of these photoanodes were performed by UV-Visible spectroscopy, and linear scanning voltammetry (LSV) respectively. The results showed that all the photoanodes produced exhibit conductivity and catalytic properties that make them attractive for water splitting application in a photoelectrochemical cell. In this context, the photoanode S₂ exhibited better photocatalytic activity than the photoanode S₁. In addition, photoanode S₂ had the lowest optical band-gap energy value (2.58 eV), which would allow better utilization of the solar spectrum.

• Journal of the Korean Ceramic Society
• /
• v.54 no.6
• /
• pp.525-529
• /
• 2017

To improve the thermal resistance of a porous borosilicate lining block, we prepared and applied polysiloxane-fumed silica-ethanol slurry on top of the block and fired the coating layer using a torch for 5 minutes at $800^{\circ}C$. We conducted magnified characterizations using a microscope and XRD analysis to observe phase transformations, and TGA-DTA analysis to determine the thermal resistance. Thermal characterizations showed improved heat resistance with relatively high polysiloxane content slurry. Cross-sectional optical microscope observation showed less melting near the surface and decreased pore formation area with higher polysiloxane content slurry. XRD analysis revealed that the block and coating layer were amorphous phases. TGA-DTA analysis showed an endothermic reaction at around $550^{\circ}C$ as the polysiloxane in the coating layer reacted to form SiOC. Therefore, coating polysiloxane on a borosilicate block contributes to preventing the melting of the block at temperatures above $800^{\circ}C$.

• Journal of the Korean Physical Society
• /
• v.80
• /
• pp.1035-1041
• /
• 2022

Nondestructive nano-characterization methods were reviewed with respect to technical aspect and practicability. Micro-photoluminescence, cathodoluminscence and Raman spectroscopy with mapping modes were investigated as optical characterization tools, while electron backscatter diffraction and piezoresponse force microscopy were introduced as monitoring techniques for the crystallographic and electromechanical properties. Especially, the spatial resolution of the data acquisition and analysis was carefully inspected in the representative semiconducting nanomaterial systems. Some of efforts to overcome the limit of these characterizations were also taken into consideration.