In recent years, the challenge of higher energy efficiency has emerged as urban buildings have become taller, and the area of window glasses has increased. To address the problem of energy efficiency in buildings, research on smart windows is being actively conducted. In this study, an accelerated experiment for thermal stability was conducted to fabricate a liquid crystal cell applicable to external windows. It was confirmed from the study that the function is maintained even in a high-temperature external environment through the change in transmittance by voltage. Compared with the initial transmittance, after the passage of time, the smart window cell to which the sealant was applied showed a small change in transmittance of 1~2%. This result confirmed the thermal stability of the liquid crystal-based smart window.

ZnS was chemically deposited as a buffer layer alternative to CdS, for use as a Cd-free buffer layer in Cu(In_1-xGa_x)Se₂ (CIGS) solar cells. The deposition of a thin film of ZnS was carried out by chemical bath deposition, following which the structural and optical properties of the ZnS layer were studied. For the experiments, zinc sulfate hepta-hydrate (ZnSO₄·7H₂O), thiourea (SC(NH₂)₂), and ammonia (NH₄OH) were used as the reacting agents. The mole concentrations of ZnSO₄ and SC(NH₂)₂ were fixed at 0.03 M and 0.8 M, respectively, while that of ammonia, which acts as a complexing agent, was varied from 0.3 M to 3.5 M. By varying the mole concentration of ammonia, optimal values for parameters like optical transmission, deposition rate, and surface morphology were determined. For the fixed mole concentrations of 0.03 M ZnSO₄·7H₂O and 0.8 M SC(NH₂)₂, it was established that 3.0 M of ammonia could provide optimal values of the deposition rate (5.5 nm/min), average optical transmittance (81%), and energy band gap (3.81 eV), rendering the chemically deposited ZnS suitable for use as a Cd-free buffer layer in CIGS solar cells.

Cadmium compounds with one dimension (1D) nanostructures have attracted attention for their excellent electrical and optical properties. In this study, vertically aligned CdTe-Si nanostructures with high density were synthesized by several simple chemical reactions. First, l D Te nanostructures were synthesized by silver assisted chemical Si wafer etching followed by a galvanic displacement reaction of the etched Si nanowires. Nanowire length was controlled from 1 to 25 μm by adjusting etching time. The Si nanowire galvanic displacement reaction in HTeO₂ + electrolyte created hybrid 1D Te-branched Si nanostructures. The sequential topochemical reaction resulted in Ag₂Te-Si nanostructures, and the cation exchange reaction with the hybrid 1D Te-branched Si nanostructures resulted in CdTe-Si nanostructures. Wet chemical processes including metal assisted etching, galvanic displacement, topochemical and cation exchange reactions are proposed as simple routes to fabricate large scale, vertically aligned CdTe-Si hybrid nanostructures with high density.

Although there are existing Residual Current Protective Device (RCD) including detect electric leakage and elements such as short circuit and surge, the occurrence of incidents caused by electric faults, including fire, are still constant. The purpose of this study is to analyze the causes of accidents through the electric field distribution in the interpretation of the fault contact breaker. Simulation results by the arc fault has shown the convergence of temperature and electric field to the defect. Through their simulation results, the main cause of erosion phenomena in circuit breaker bar is the electric arc by concentration of electric field not due to dissolve by temperature.

In this research, we focused on the improvement of cy3 dye’s characteristics for LCD color filter. Solubility and thermal stability are main characteristics of dyes for LCD color filter. We performed experiment to change counter cation of cy3 dyes with alkoxy substituent for these purposes. These cy3 dyes (1b∼5b) were prepared through the synthetic procedure of three steps. The synthesized new cy3 dyes were charaterized by using NMR, FT-IR, UV/Vis spectroscopy, and TGA. These cy3 dyes showed purple color and maximum absorption wavelength (λmax) in the range of 578∼590 nm in UV/Vis spectrum. We confirmed that solubility and thermal stability of cy3 dyes were dependent on the structure of counter cation. Cy3 dyes with alkoxy substituent have good solubility in organic solvents such as dichloromethane, methanol, and acetone. Especially, Cy3 dye with 4-nitrobenzyl counter cation (5b) gave excellent solubility characteristics.

This paper suggests a high performance lateral super barrier rectifier (Lateral SBR) device which has the advantages of both Schottky diode and pn junction, that is, low forward voltage and low leakage current, respectively. Advantage of the proposed lateral SBR is that it can be easily implemented and integrated in current BCD platform. As a result of simulation using TCAD, BVdss = 48 V, VF = 0.38 V @ IF = 35 mA, T_j = 150℃ were obtained with very low leakage current characteristic of 3.25 uA

In this research, we focused on the development of cy3 dye with high thermal stability and good solubility for LCD color filter. Cy3 dyes were prepared through the synthetic procedure of two steps. The synthesized cy3 dyes were characterized by using NMR, FT-IR, UV/Vis spectroscopy, and TGA. These cy3 dyes showed maximum absorption wave length (λmax) in the range of 549∼555 nm in UV/Vis spectrum. And we confirmed that solubility characteristics and thermal stability of cy3 dyes were dependent on the structure of counter cation. Cy3 dyes with methyl counter cation and ethyl counter cation have good solubility in organic solvents such as chloroform, ethanol, and PGME. Moreover, Cy3 dye with ethyl counter cation gave excellent thermal stability in TGA thermograms. And Cy3 dye with ethyl counter cation showed good result in photoresist film test.

In this study, chemical bath deposition method was used to grow Zinc sulfide(ZnS) thin filmsfrom NH3/SC(NH2)2/ZnSO4 solutions at 90℃. ZnS thin films have been prepared onto ITO glass. Theconcentrations of ZnSO4 and NH were varied while the concentration of Thiourea was fixed in 0.52 M. Structural, optical, electrical characteristic of ZnS thin films were measured. The physical and opticalproperties of different ZnS thin films were influenced severely by the concentration of the two reactingchemicals. The optimal concentration of ZnSO4 and NH3 was 0.085 M and 1.6 M, respectively.

Abstract: We focused on the development of red azo colorants with high thermal stability and good solubility for LCD color filter in this research. For the synthesis of hybrid azo colorants, we used the couplers of aniline. naphthol and benzoimidazol functional group. The synthesized hybrid azo colorants were charaterized by using NMR, UV/visihle spec troscopy, FT - JR. EA and 1`GA. They represented the maximum absorption wavelengths which are longer than 500 urn in UV/visible spectrum. So they were confirmed to be suitable for red colorants of LCD color filter. Azo compound (la, lh) with aniline functional group had good soluhility in organic solvents such as acetone, methanol, chloroform and PGMEA. Moreover azo compounds (ic, id and Ic) with naphthol and benzoimidazolone functional group gave excellent thermal stability higher than 250t in TGA thermograms.

The composites composed of conducting polymer (MEH-PPV), CdTe nanoparticles, and multiwalled carbon nanotubes (MWNTs) were spectroscopically and electrically characterized in their thin films. The composite films were prepared by spray coating. These composites were prepared from the mixture solution of MEH-PPV and CdTe-embedded MWNTs, in which CdTe nanoparticles were electrostatically bound to MWNTs. UV/vis and PL spectra were analyzed to investigate the optical absorbance and emission of the composite films. In addition, their structural, electrochemical, and electrical properties were studied by transmission electron microscopy, cyclic voltammetry, and I-V measurement.

The water soluble quantum dots (QDs) are synthesized by the phase transfer and silica coating reaction. The photoluminescence intensity of silica-coated QDs are mainly affected by the amount of phase transfer agent, SDS (sodium dodecyl sulfate), and the maximum value is obtained at the cmc (critical micell concentration) concentration of SDS in the phase transfer reaction. Based on fluorescence spectra and field emission transmission electron microscope (FETEM), the energy transfer rate by forster resonance energy transfer (FRET) is increasing with the thickness of the silica shell coated on CdSe/ZnS QDs.

The K-PCS and W-CDMA dual band dielectric duplexer and bandpass filters have been designed and fabricated. The dual band duplexer consists of the separate monoblock K-PCS and W-CDMA duplexers using common antenna port. The coupling capacitance and I/O impedance matching have been designed to minimize the cross interference between the bands. Isolations of crosspoint between Tx and Rx in K-PCS and W-CDMA dualband were about 47 dB and 100 dB, respectively. On the other hand, isolations of Tx and Rx in K-PCS and W-CDMA were about 66 dB and 65 dB, respectively. The difference between 47 dB and 100 dB originated from the different center frequencies in Tx and Rx of K-PCS and W-CDMA bands. The coupling capacitance of the bandwidth, I/O capacitance of I/O matching and impedance matching, and various capacitances were important role to fabricate the dielectric duplexer and bandpass filters.

The spherical mesoporous silica is synthesized and incorporated with CdSe/ZnS quantum dots(QDs) for preparing micro beads to detect toxic and bio-materials with high sensitivity. The spherical silica beads with the brunauer-emmett-telle(BET) average pore size of 15 nm were prepared with a ratio 1, 3, 5-trimethylbenzen, as a swelling agent, to the block-copolymer template surfactant of over 1 and under vigorous mixing condition. The surface of spherical mesoporous silica is modified using octadecylsilane for incorporating QDs. Based on photoluminescence(PL) spectra, the relative brightness of mesoporous silica beads incorporated with 10 nM of QDs is 79,000 times brighter than that of Rodamine 6 G.

Znic sulfide (ZnS) thin films were deposited on glass substrates by radio frequency magnetron sputtering. The substrate temperature varied from room temperature (RT) to 500℃. The structural and optical properties of ZnS films were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive analysis of X-ray (EDAX) and UV-visible transmission spectra. The XRD analyses reveal that ZnS films have cubic structures with (111) preferential orientation, whereas the diffraction patterns sharpen with the increase in substrate temperatures. The FESEM images indicate that ZnS films deposited at 400℃ have nano-sized grains with a grain size of∼ 67 nm. The films exhibit relatively high transmittance of 80% in the visible region, with an energy band gap of 3.71 eV. One obvious result is that the energy band gap of the film increases with increasing the substrate temperatures.

In this paper, CdS thin films, which were widely used window layer of the CdTe and the Cu(In,Ga)Se2 thin film solar cell, were grown by chemical bath deposition, and effects of pH of reaction solution on the structural and optical properties were investigated. For pH<10.5, as the pH of reaction solution was higher, the deposition rate of CdS films was increased by improving ion-by-ion reaction in the substrate surface and the crystallinity of the films was improved. However, when the pH was higher than 10.5, the deposition rate was decreased because of smaller Cd2+ ion concentration in the reaction solution. Also, the crystallinity of the films were deteriorated. The CdS films deposited at lower pH showed poor optical transmittance due to adsorbed colloidal particles, while the transmittance was improved for higher pH.

Citations

• Influence of CdS Post-deposition Treatment on CIGS Solar Cells
  Soo-Min Kwon, SangMok Kim, Chan-Wook Jeon
  New & Renewable Energy.2016; 12(1): 26.     CrossRef

In this study, we proposed a novel electrode structure for the fringe field switching (FFS) mode LCD and performed a three-dimensional computer simulation to calculate the optical transmittance for the new structure. In the simulation Erickson-leslie equation and Berreman 4×4 matrix were used for obtaining the director distribution profiles of liquid crystal molecules and the electro-optical characteristics, respectively. Considering the complexity of the motional equation of the liquid crystal molecules, FDM (finite difference method) was used as a numerical method. From the results, We revealed that the light transmission of the newly designed pixel structure is expended to the edge of the pixel electrode. We also confirmed that the light transmittance increased more than 13% compared to that of the conventional electrode structure.

CdSe films were deposited on glass substrates (CdSe/glass) by thermal evaporation. Substrate temperature was lowered by cooling substrate holder with liquid nitrogen. Substrate temperatures were 200℃, 0℃ and -40℃. The crystallographic properties and surface morphologies of the CdSe/glass films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical and electrical properties of the films were investigated by dependence of energy gap, photosensitivity and resistivity on the substrate temperature. CdSe/glass showed energy gap of ～1.72 eV regardless of substrate temperature. The resistivity of the films decreased to 0.5 Ωcm by lowering the substrate temperature to -40℃. The CdSe/glass films prepared at 0℃ showed the highest photosensitivity among the films in this study.

Citations

• Reflection Characteristics of Electroplated Deposits on LED Lead frame with Plating Condition
  SeHo Kee, Wonjoong Kim, JaePil Jung
  Journal of the Microelectronics and Packaging Society.2013; 20(2): 29.     CrossRef

Citations

• Effect of Pre/Post-Treatment on the Performance of Cu(In,Ga)(S,Se)2 Absorber Layer Manufactured in a Two-Step Process
  A-Hyun Kim, GyeongA Lee, Chan-Wook Jeon
  New & Renewable Energy.2021; 17(4): 36.     CrossRef