NTC (negative temperature coefficient) thermistors are semiconductor ceramics whose resistance decreases with increasing temperature, making them essential components in various temperature sensing applications. Typically, ceramic materials are sintered at high temperatures exceeding 1,150°C. However, in laminated devices incorporating internal electrodes, co-sintering can lead to cracking and mechanical failure due to mismatches in the thermal expansion coefficients between the ceramic layers and metal-based electrodes. Moreover, the use of noble metal electrodes increases production costs. To address these challenges, a low-temperature sintering approach is required. Previous studies have demonstrated that incorporating glass frit can reduce the sintering temperature of ceramics, although this often results in increased electrical resistance. In this study, NiMnCoO₄ (NMC) ceramics, as a representative NTC thermistor composition, were prepared with the addition of 10 wt% glass frit. To mitigate the resulting increase in resistivity, trace amounts (1 wt%) of various metal oxides, including CuO, ZnO, and MnO, were introduced. Among these, the addition of CuO notably decreased both the resistivity and B constant values. In contrast, MnO had little effect on resistivity, while ZnO led to an increase. With respect to the B25/85 constant, samples containing MnO and ZnO exhibited higher values than those without metal oxide additives. These findings indicate that the incorporation of 1 wt% CuO is effective in reducing the increased resistivity in NMC ceramics subjected to low-temperature sintering via glass frit addition.

NTC thermistors are essential components widely used for temperature sensing in various electronic sensor applications. However, conventional NTC thermistor ceramics typically require high sintering temperatures above 1150℃, necessitating the use of high-cost noble metal electrodes such as palladium (Pd) or platinum (Pt), which increases the overall manufacturing cost. In this study, low-melting-point oxides were successfully introduced as sintering aids to reduce the sintering temperature of NiMnCoO₄-based semiconducting ceramics. As the additive content increased, the B constant and average grain size exhibited an increasing trend, while the sample containing 5 wt% additives showed the lowest room-temperature resistivity. Furthermore, samples sintered at 1000℃ demonstrated slightly higher room-temperature resistivity and B constant values compared to those sintered at 1150℃. These results confirm that the addition of low-melting-point oxides is effective in lowering the sintering temperature of NiMnCoO₄ ceramics, suggesting the potential for reducing production costs and improving design flexibility in thermistor fabrication.

This study explores the realization of high-efficiency white LED lighting by applying cyan-emitting quantum dot (CQD) and red-emitting quantum dot (R-QD) deposition without any host matrix onto a yellow-emitting phosphor-in-glass (YPIG) substrate using an aerosol-assisted deposition (AAD) process. The AAD process facilitates the direct formation of densely packed QD-deposited layers on the substrate, effectively addressing challenges such as optical efficiency loss and degradation typically associated with organic host matrices. C-QD and R-QD coatings, deposited with thicknesses of 0.84 μm and 0.77 μm on the upper and lower Y-PIG substrate, exhibited robust color conversion properties. These films achieved a luminous efficacy of 77 lm/W and a high color rendering index (CRI) of 96.8 under blue light excitation. The dual-layer structure produced highquality light closely resembling natural daylight, as confirmed through real image. Consequently, the research suggests the potential of AAD-based QD deposition to achieve superior performance without relying on host matrices, offering a viable solution for high-efficiency lighting applications. Further optimization of deposition parameters and exploration of diverse substrates and QD material combinations are expected to expand the applicability of this technique in future research.

The expansion of lithium-ion battery usage beyond portable electronic devices to electric vehicles and energy storage systems is driven by their high energy density and favorable cycle characteristics. Enhancing the stability and performance of these batteries involves exploring solid electrolytes as alternatives to liquid ones. While sulfide-based solid electrolytes have received significant attention for commercialization, research on amorphous-phase glass solid electrolytes in oxide-based systems remains limited. Here, we investigate the glass transition temperatures and sintering behaviors by changing the molecular ratio of Li₂O/B₂O₃ in borate glass comprising Li₂O-B₂O₃-Al₂O₃ system. The glass transition temperature is decreasing as increasing the amount of Li₂O. When we sintered at 450℃, just above the glass transition temperature, the samples did not consolidate well, while the proper sintered samples could be obtained under the higher temperature. We successfully obtained the borate glass ceramics phases by melt-quenching method, and the sintering characteristics are investigated. Future studies could explore optimizing ion conductivity through refining processing conditions, adjusting the glass former-to-modifier ratio, and incorporating additional Li salt to enhance the ionic conductivity.

This work focuses on improving the light-harvesting efficiency of thin-film silicon solar cells through innovative multi-architecture surface modifications. To create a regular optical structure, a lithographic process was performed to form it on a glass substrate through various etching processes, from Etch-1 to Etch-3. AZO was deposited on top of the structures and re-etched to create a multi-architectural surface. These surface-modified structures improved the light absorption and overall performance of the solar cell through changes in optical and physical properties, which we will analyze. In addition, we investigated the effect of post-cleaning on the etched glass structures through EDX analysis to understand the mechanism of the etching action. The results of this study are expected to provide important guidelines for the design and fabrication of solar cells and other photovoltaic devices.

Integrating dielectric materials into LTCC is a convenient method to increase the integration density in electronic circuits. To enable co-firing of the high-k and low-k dielectric LTCC materials in a multi-material hetero-laminate, the shrinkage characteristics of both materials should be similar. Moreover, thermal expansion mismatch between materials during co-firing should be minimized. The alternating stacking of an LTCC with silica filler and that with calcium-zirconate filler was observed to examine the use of the same glass in different LTCCs to minimize the difference in shrinkage and thermal expansion coefficient. For the LTCC of silica filler with a low dielectric constant and that of calcium zirconate filler with a high dielectric constant, the amount of shrinkage was examined through a thermomechanical analysis, and the predicted appropriate fraction of each filler was applied to green sheets by tape casting. The green sheets of different fillers were alternatingly laminated to the thickness of 500 ㎛. As a result of examining the junction, it was observed through SEM that a complete bonding was achieved by constrained sintering in the structure of ‘calcium zirconate 50 vol%-silica 30 vol%-calcium zirconate 50 vol%’.

In this study, the following results were obtained by analysis of electric properties with FT-IR, DSC, XRD, and SEM, in the range of temperature 30~160℃ and frequency 0.1~200 kHz, when filling agent (0~100 phr) and silicone oil (0~12 phr) were added to raw silicone rubber. In the case of 100 phr mixed samples, the relative dielectric constant εr gradually decreased from 4.3 to 3.96 as frequency increased, and the dielectric loss tan δ decreased to 0.01 at 300 Hz, then increased to 0.022 at 30 kHz, then decreased to 200 kHz. The FT-IR analysis identified the same binding structure according to the chemical composition of added silica (SiO₂). Through DSC analysis, we could determine the change of heat quantity and the glass transition temperature of each specimen. In the XRD analysis, it was found that the images SiO₂, TiO₂, and Fe₂O₃ appeared for specimens with 0%, 50% and 100% filling agent. Finally, the SEM analysis confirmed that particles of 0.5 to 1.5 μm size with silica (SiO₂) mixing were dispersed evenly.

This study investigated the influence of the viscoelastic property of slag when producing glass fiber, MFS631 with 60% of manganese slag, 30% of steel slag, and 10% of silica stone. To fabricate the MFS631 glass bulk, slag materials were placed in an alumina crucible, melted at 1,550℃ for 2 h, and then annealed at 600℃ for 2 h. It was found that glass is non-crystalline through X-ray diffraction analysis. MFS631 fiber was produced at speed in the range of 100~300 rpm at 1,150℃. The loss modulus (G″) and storage modulus (G′) of the produced glass fiber were evaluated at high temperatures. G′ and G″ of MFS631 were greater than 893℃, and the modulus value was 136,860 pa. This is similar to the results of a general E-glass fiber graph. Therefore, it was concluded that its spinnability is similar to that of E-glass fiber; therefore, it can be commercialized.

Red phosphor in glasses (PiGs) for automotive light-emitting diode (LED) applications were fabricated with 620-nm CaAlSiN₃:Eu²⁺ phosphor and Pb-free silicate glass. PiGs were synthesized and mounted on high-power blue LED to make a monochromatic red LED. PiGs were simple mixtures of red phosphor and transparent glass powder. After being fabricated with uniaxial press and CIP at 300 MPa for 20 min, the green bodies were thermally treated at 550℃ for 30 min to produce high dense PiGs. As the phosphor content increased, the density of the sintered body decreased and PiGs containing 30% phosphor had a full sintered density. Changes in photoluminescence spectra and color coordination were studied by varying the thickness of plates that were mounted after optical polishing. As a result of the optical spectrum and color coordinates, PiG plate with 210 μm thickness showed a color purity of 99.7%. In order to evaluate the thermal stability, the thermal quenching characteristics were measured at temperatures of 30~150℃. The results showed that the red PIG plates were 30% more thermally stable compared to the AlGaInP red chip.

We researched about a bulk metallic glass system as an additive to an Ag paste for high temperature thermoelectric modules. Bulk metallic glass (BMG) ribbons were produced by using a rapid solidification process (RSP) under a cooling rate condition higher than 10℃/sec. We investigated BMG characteristics of the ribbons by means of x-ray diffraction (XRD) and differential scanning calorimetry (DSC) in order to evaluate the glass transition temperature (Tg) and the recrystallization temperature (Tx) lower than 400℃. A milling process was also developed to apply the BMG ribbons to a commercial Al paste as an additive for lower sintering temperature.

We investigated the structure of an ultra-thin insulating board with low thermal conductivity along z-axis, which was based on the idea of void layers created during the glass infiltration process for the zero-shrinkage low-temperature co-fired ceramic (LTCC) technology. An alumina and four glass powders were chosen and prepared as green sheets by the tape casting method. After comparison of the four glass powders, bismuth glass was selected for the experiment. Since there is no notable reactivity between alumina and bismuth glass, alumina was selected as the supporting additive in glass layers. With 2.5 vol% of alumina powder, glass green sheets were prepared and stacked alternately with alumina green sheet to form the ‘alumina/glass (including alumina additive)/alumina’ structure. The stacked green sheets were sintered into an insulating substrate. Scanning electron microscopy revealed that the additive alumina formed supporting bridges in void layers. The depth and number of the stacking layers were varied to examine the insulating property. The lowest thermal conductivity obtained was 0.23 W/mK with a 500-㎛-thick substrate.

Terahertz time-domain spectroscopy has been used to study the optical properties of Pr³⁺-doped selenide glasses. The complex refractive indexes of Pr³⁺-selenide glasses were measured in a frequency range from 0.3 to 1.5 THz. The real and imaginary refractive indexes increased with increasing frequency and Pr³⁺ ion concentration. The obtained result indicated that the phonon modes of the Pr³⁺-doped selenide glasses shift to lower frequencies with the concentration of Pr³⁺ ions. The theory of far-infrared absorption in amorphous materials was used to analyze the results. The measured data showed that the disorder-induced terahertz absorption increased with increasing Pr³⁺ ion concentration.

Thermal and structural stability in the glass transition region of chalcogenide glasses has been investigated in terms of thermodynamics for application to various optoelectronic devices. In this study, the compositions of Ge_xSb₂₀Se_80-x (x = 10, 15, 20, 25, and 30) were selected to investigate the glass stability according to germanium ratios. The chalcogenide bulks were fabricated by using a traditional melt-quenching method. Thin films were deposited by a thermal evaporation system, maintaining the deposition ratio of 3~5 A in order to have uniformity. The thermal and structural properties were measured by a differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The DSC analysis provided thermal parameters and theoretical glass region stabilities. The XRD analysis supported the theoretical stabilities because of where the crystallization peak data occurred.

Induction cooktop has a great attention due to its safety, quick heating and cleanness compared to gas oven. However, the materials for induction cookware is limited to steel or stainless-steel which has the magnetic property. Recently, it has been tried to apply various porcelain to induction cookware after printing the silver layer on the bottom of cookware plates and co-firing at high temperature. Glass frits are added in the silver paste to improve an adhesion force between porcelain materials containers and transferred silver layer. The hybrid silver pastes for induction cookware requires the proper electrical resistance and the thermal conductivity with base plates. After sintering process at 800℃, a part of melted glass migrated to the porcelain and the rest of the glass frit was exposed to the surface. It was confirmed that most of the glass frit formed an adhesion layer between the porcelain and transferred silver layer that enhances the adhesion force.

In this study, the effect of vanadium oxide (V₂O₅) content and pre-sintering atmosphere on sealing property of glass frit that consisted of V₂O₅-BaO-ZnO-P₂O₅-TeO₂-CuO-Fe₂O₃ SeO₂ was investigated by XPS (X-ray photoelectron spectroscopy). The content of V₂O₅ was changed to 15, 30, and 45 mol%, and the pre-sintering was carried out in air and N₂ condition, respectively. XPS analysis conducted before and after laser irradiation with identical sample. Before laser treatment, glass frits that were pre-sintered at air condition showed both V₄₊and V₅₊, but the valence state was changed to V₅₊ after laser irradiation when the glass frits contained 30 and 45 mol% V₂O₅; this change led to non-adhesive property. On the other hand, glass frits that were pre-sintered at N₂ condition exhibited only V₄₊ and it showed fine adhesion irrespective of the V₂O₅ content. As a result, the existence of V₄₊ seems to be a major factor for controlling the adhesive property of glass frit for laser sealing.

The basic characteristics of glass are highly fragile and brittle consequences the ultimate purpose of glass manufacturing is to make a transparent glass with complex shape. In order to solve this problem, mechanical properties of glass can be increased by crystallization of its amorphous glass. However, glass-ceramics has become opaque through crystallization process due to the distracted interface of glass by precipitated particles. This study has been investigated thermal processing conditions of LAS transparent glass-ceramic by using DTA (differential thermal analysis), in order to control size of precipitated particle and then fabricate transparent glass-ceramic. DTA indicated that crystallization peak area was declined with increased nucleation temperature. Subsequently, we have been established optimum temperature for crystallization depending on the nucleation temperature. The transmission and thermal expansion were measured after crystallization, and the size of precipitated particle was identified in range of 20~100 nm by FE-SEM. In addition, by setting the optimized crystallization condition, with high transmission and low thermal expansion glass was synthesized through this experiment.

In this study, we developed a lead-free P_{2}`O_{5}`-V_{2}O_{5}-ZnO glass frit for sealing OLED using laser irradiation. The frit satisfied the characteristics required for laser sealing such as low glass transition temperature, low coefficient of thermal expansion (CTE), high water-resistance, and high absorption at the wavelength of the laser beam. Ceramic fillers were added to the glass frit in order to further reduce and match its CTE with that of the commercial glass substrate. The addition of Zirconium Tungsten Phosphate (ZWP) to the frit yielded the most desirable results, reducing the CTE to 45.4×10^{-7}/℃, which is very close to that of the glass substrate (44.0×10^{-7}/℃). Successful formation of a solid sealing layer was observed by optical and scanning electron microscopy.

To provide the clear images from the direct light on electrical board and display devices, anti glare treatment of display cover glass is needed. In this study, the effects of surface treatment temperature, concentration, and etching solution coating thickness of the gel phase on optical elements control such as gloss, haze of reflected light and transmittance, were investigated. Cover glasses were treated at different coating thickness and additive concentration. The optical properties were examined using spectrophotometer, gloss and haze meter. The surface morphology and roughness were measured by the optical microscope and Ra measuring instrument. The etching rate and surface morphologies were dramatically affected by the concentration of acid additive in the viscous gel because of re-crystallization of components in the etching solution, hydrogel formation and coagulant after coating on glass substrate. In our experimental range, cover glass which is surface-treated with various optical properties as well as the morphology uniformity was obtained; in particular, optical properties could be controlled by etching solution coating thickness of the gel phase and the concentration of additive. The gloss was depended on the surface roughness and it showed the linear relationship between optical transmittance and haze of reflected light, respectively.

In this study, we fabricated a thermoelectric module made of nanoparticles (NPs) and glass fibers investigated its thermoelectric characteristics. P-type HgTe and n-type HgSe NPs synthesized by colloidal method were used as thermoelectric materials and glass fibers were used as spacers between the hot and cold electrodes of the thermoelectric module. In the module, the average Seebeck coefficients of the HgTe and HgSe NPs were 1260 and -628 μV/K, respectively. The p-n module generated about a voltage of 11.9 mV and showed a power density of 1.6×10-5 μW/cm2 at a temperature difference of 7.5 K.

Glass ceramic has a high mechanical strength and low sintering temperature. So, it can beused as a thick film substrate or a high strength insulator. A series of glass ceramic samples based onMgO-Al2O3-SiO2-ZrO2 (MASZ) were prepared by melting at 1,600℃, roll-quenching and heat treatment atvarious temperatures from 900℃ to 1,400℃. Dependent on the heat treatment temperature used, glassceramics with different crystal phases were obtained. Their nucleation behavior, microstructure andmechanical properties were investigated with differential thermal analysis (DTA), X-ray diffraction (XRD),scanning electron microscopy (SEM), and Vicker`s hardness testing machine. With increasing the heattreatment temperature of MASZ samples, their hardness and toughness initially increase and then reachthe maximum points at 1,300℃, and begin to decrease at above this temperature, which is likely to bedue to the softening of glass ceramics. As the content of ZrO2 in MAS glass ceramics increases from 7.0wt.% to 13 wt.%, Vicker`s hardness and fracture toughness increase from 853 Kg/mm2 to 878 Kg/mm2and 1.6 MPa??m1/2 to 2.4 MPa??m1/2 respectively, which seems to be related with the nucleation of elongatedphases like fiber.

We investigated dielectric relaxation properties of 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics byaddition (0∼0.3 wt%) of (Ba,Ca)SiO3 glass frit. All composition of 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 added(Ba,Ca)SiO3 glass frit showed the same crystallographic properties, coexistence of orthorhombic andtetragonal phase. By increasing addition of (Ba,Ca)SiO3 glass frit, the Curie temperatures of0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics were decreased, whereas maximum dielectric constants of0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics were dramatically increased. Especially the deviations of Curietemperature 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics were increased by increasing amount of(Ba,Ca)SiO3 glass frit, and it indicated that 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics added (Ba,Ca)SiO3glass frit have relaxor characteristics.

Aspheric lenses used in the thermal imaging are typically fabricated using expensive single-crystal materials (Ge and ZnS, etc.) by the costly single point diamond turning (SPDT) process. As a potential solution to reduce cost, compression molding method using chalcogenide glass has been attracted to fabricate IR optic. Thermal deformation of a molded lens should be compensated to fabricate chalcogenide aspheric lens with form accuracy of the submicron-order. The thermal deformation phenomenon of molded lens was analyzed ant then compensation using mold iteration process is followed to fabricate the high accuracy optic. Consequently, it is obvious that compensation of thermal deformation is critical and useful enough to be adopted to fabricate the lens by molding method.

In this paper, we have researched semiconductor optical filters to solve the problem of the high failure rate that are recognize bad of financial account, jam of financial account and the ATM service interruption due to failure of accurate location information among the operation of the ATM (automatic teller machine) systems. A semiconductor optical filters that have high resolution and less diffuse, high transmittance are able to detect the information of financial account surface accurately. Therefore, it is a stable filter that is able to minimize the incidence of disability. In this paper, we drew the determinants by element for implement an excellent semiconductor optical filters. Based on this, we had to be able to implement the semiconductor optical filter that is able to be mounted on the actual ATM system through future studies.

The front electrode should be used to make solar cell panel so as to collect electron. The front electrode is used by paste type, printed on the Si-solar cell wafer and sintered at about 800℃. The paste is composed Ag powder and glass frit which make the ohmic contact between Ag electrode and n-type semiconductor layer. From the previous study, the Ag electrodes which used two commercial glass frit of Bi-system were so different on the interface resistance. The main composition of them was Bi-Zn-B-Si-O and few additives added in one of them. In this study, glass frit was made with the ratio of Bi2O3 and ZnO on the main composition, and then paste using glass frit was prepared respectively. And, also, the paste using the glass frit added oxide additives were prepared. The change of interface resistance was not large with the ratio of Bi2O3 and ZnO. In the case of G6 glass frit, 78 wt% Bi2O3 addition, the interface resistance was 190 Ω and most low. In the glass frit added oxide, the case of Ca increased over 10 times than it of G6 glass frit on the interface resistance. It was thaught that after sintering, Ca added glass frit was not flowed to the interface between Ag electrode and wafer but was in the Ag electrode.

Zinc oxide(ZnO) was sputtered on various glass and flexible substrates such as polyethylene terephthalate(PET) and polycarbonate(PC). A Q-switched Nd:YVO4 laser with a wavelength of 1,064 nm was used for the direct etching of ZnO films. It was possible to obtain laser etched line patterns on the ZnO films on PC substrate at some specific laser beam conditions. In the flexible substrates, more thermal energy of laser beam is expected to be spreaded for the etching process.

Chalcogenide glass has superior property of optical transmittance in the infrared region. Glass made using Ge-Se how many important optical applications. We have determined the composite formular of Ge0.25Se0.75 to be the GeSe chalcogenide glass composition appropriate for IR lenses. Also, the optical,thermal and physical characteristics of chalcogenide glass depended on the composition ratio. GeSe bulk sample is produced using the traditional melt-quenching method. The optical, structural, thermal and physical properties of the compound were measured by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Differential scanning calorimeter (DSC), and Scanning electron microscope (SEM) respectively.

(Na,K)NbO3-based piezoelectric ceramics were synthesized by a liquid phase sintering method with a selected glass frit. The effects of the content of the glass frit and the sintering temperature on the microstructure and the electrical properties of the samples were investigated. With the 0.1 wt% of glass frit content, (Na0.52K0.44Li0.06)(Nb0.84Ta0.10Sb0.06)O3 (NKL-NTS) ceramics showed the maximum values of the relative density (99.1%) and the electro-mechanical coupling factor (kp: 0.32) at the sintering temperature of 1,050℃. It might mean that a liquid phase sintering with a suitable glass frit having the lower flow temperature could improve the relative density and the piezoelectric properties.

Recently, remote phosphor is reported for white LED enhancing of phosphor efficiency compared with conventional phosphor-based W-LED. In this study, Remote phosphor was produced by screen printing coating on glass substrate with phosphor contents rated paste and heat treatment. The paste consists of phosphor, lowest softening glass frit and organic binders. Remote phosphor can be well controlled by varying the phosphor content rated paste. After mounting remote phosphor on top of blue LED chip, CCT, CRI, and luminance efficiency were measured. The measurement results showed that CCT, CRI. and luminance efficiency were 6,645, 68, and 1,161 n/W in phosphor 80 wt.% remote phosphor sintered at 600℃.

With the recent development of less-costly uncooled detector technology, expensive optics are among the remaining significant cost drivers in the thermography camera. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glass has been studied in recent years. We report on the molding and evaluation of a ultra-precision chalcogenide-glass lens for the thermography camera for body-temperature monitoring. In addition, we fabricated prototype thermography camera using the chalcogenide-glass lens and obtained the thermal image from the camera. In this work, it was found out that thermography camera discerned body-temperature between 20 and 50℃ through the analysis of thermal image. It is confirmed that thermography camera using the chalcogenide-glass lens is applicable to the body-temperature monitoring system.

PTFE composites for use of microwave substrate were fabricated by impregnation and heat treatment fabrication with glass fabric. This study shows dielectric properties such as dielectric constant and loss can be controlled by thickness of PTFE composite with of pressure condition in heating press process. The dielectric constant of the PTFE composites has decreasing tendency as given higher pressure condition. The dielectric loss has similar result too. Especially, the case of the dielectric loss was affected by the condition of pressure at heating press and had the best performance under 3 MPa. In order to see the reason why thickness conditions make different, their microstructures were also observed.