TiO₂ 나노입자가 혼합된 봉지재를 적용한 LED 패키지의 광효율 특성 평가

이태영,김경호,김미송,고은수,최종현,문경식,김목순,유세훈,Lee, Tae-Young,Kim, Kyoung-Ho,Kim, Mi-Song,Ko, Eun-Soo,Chio, Jong-Hyun,Moon, Kyoung-Sik,Kim, Mok-Soon,Yoo, Sehoon 한국마이크로전자및패키징학회 2014 마이크로전자 및 패키징학회지 Vol.21 No.3

본 연구에서는 $TiO_2$ 나노입자를 LED패키지의 봉지재인 실리콘에 분산시키고, 이에 따른 굴절률, 투과율 및 광효율 변화를 평가하였다. $TiO_2$ 나노입자는 LED 봉지재의 굴절율을 증가시켜 LED 패키지의 광추출 효율을 향상시키기 위해 봉지재에 적용되었다. $TiO_2$는 수열합성법을 통해 합성되었고, 합성된 $TiO_2$ 입자에 긴 체인구조의 vinyl silane을 코팅하여 분산시켰다. 분산 처리를 실시한 후에는 대부분의 $TiO_2$ 나노입자가 10~40 nm 이하로 분산되었으나, 100 nm 이상의 긴 입자도 관찰되었다. 실리콘 봉지재에 $TiO_2$ 나노입자 양이 증가할수록 굴절율은 증가하였으나, 투과율은 감소하였다. $TiO_2$ 나노입자가 포함된 실리콘 봉지재로 LED 패키지를 제조하였고, $TiO_2$ 나노입자가 분산된 LED가 $TiO_2$ 나노입자가 없는 LED패키지에 비해 약 13% 이상 광효율이 향상되었다. $TiO_2$-nanoparticle-dispersed silicone was applied to a LED package and the light efficiency of the LED package was evaluated in this study. The addition of $TiO_2$ nanoparticles in silicone increased refractive index, which improved the light efficiency of the LED package. The $TiO_2$ nanoparticles were fabricated by hydrothermal synthesis and were dispsersed by a vinyl silane coating treatment. After the silane treatment, the $TiO_2$ nanoparticles dispersed with diameters of 10~40 nm but rod-shape $TiO_2$ nanoparticles with lengths of 100 nm were also observed. The refractive index increased with the $TiO_2$ concentration in silicone, while the transmittance decreased with the $TiO_2$ concentration. The light efficient of the LED package with $TiO_2$+silicone encapsulant was higher than that of the LED package with no $TiO_2$ in silicone encapsulant.

ZVI/TIO2를 이용한 폴리염화비페닐로 오염된 토양 정화

이동근,박재욱,조윤진 한국청정기술학회 2023 청정기술 Vol.29 No.2

Once a site is contaminated with polychlorinated biphenyls (PCBs), serious environmental and human health risks are inevitable. Therefore, innovative but economical in situ remediation technologies must be immediately applied to the contaminated site. Recently, nanoscale zero-valent iron (nano-ZVI) particles have successfully been applied for the dechlorination of various chlorinated organic compounds like TCE, PCE and DDT, and they are considered to be environmentally safe due to the high abundance of iron in the earth’s crust. Nano-ZVIs are much more reactive than granular ones, but tend to agglomerate due to their high surface energy and magnetic properties. In order to prevent them from being agglomerated toward larger particles, TiO2 was used as a support to immobilize the nano-ZVI particles as much as possible. 10wt% ZVI/TiO2 was prepared by adding NaBH4 slowly into an FeSO4/TiO2 aqueous slurry. In spite of their non-uniformity in size, the nano-ZVI particles were quite successfully dispersed onto the exterior surface of a non-porous TiO2 powder. The ZVI/TiO2 was then employed to degrade Aroclor 1242, a kind of PCBs standard, in spiked soil, and its reactivity towards the degradation of Aroclor 1242 was investigated. The fabricated ZVI/TiO2 degraded Aroclor 1242 in soil quite effectively, but the creation of remaining dechlorinated compounds, possibly high molecular weight hydrocarbons, in the soil was unavoidable. 부지가 폴리염화비페닐(polychlorinated biphenyls, PCBs)로 오염되면, 심각한 환경 및 건강 위해를 피할 수 없게 된다. 따라서혁신적이지만 경제성을 지니는 제자리 복원 기술이 오염 부지에 즉시 적용되어야 한다. TCE, PCE 및 DDT와 같은 염소계 유기화합물의 탈염소화를 위하여 최근에는 나노 규모의 영가-철(zero-valent iron, ZVI)이 성공적으로 적용되었고, 지구 지각에서도 풍부하게 존재하는 철은 환경적으로 안전한 것으로 통상적으로 간주된다. 입상 ZVI에 비해 나노 규모 ZVI의 반응성은훨씬 높지만, 높은 표면에너지와 자기적 물성 때문에 나노 규모 ZVI 입자들은 서로 응결된다. 서로 응결되어 큰 입자로 전환되는 것을 방지하기 위해 먼저 생성된 나노 ZVI 입자들을 가능한 고정화하기 위한 방안으로 TiO2 분말에 나노 ZVI를 담지하였다. FeSO4와 TiO2 분말의 수용액상 슬러리에 NaBH4를 천천히 첨가하여10wt% ZVI/TiO2를 제조하였다. 입자 크기의 불균일성에도 불구하고, 나노 ZVI 입자들이 TiO2 외부 표면에 성공적으로 분산되었다. 제조된 ZVI/TiO2는 PCBs의 표준 물질 일종인 Aroclor 1242로 인위적으로 오염시킨 토양의 PCBs 분해 실험에 적용되었고, Aroclor 1242 분해 성능을 관찰하였다. 제조된 ZVI/TiO2는 Aroclor 1242 분해에 꽤 높은 반응성을 보였지만, 분자량이 큰 탄화수소로 판단되는 화합물이 부산물로생성되어 토양에 잔류하는 것은 피할 수 없었다.

TiO2 코팅 고정화 기술의 장기 공용성 시험에 따른 NOx 제거효율 평가

김광현,안희락,이승우,김영규 한국도로학회 2023 한국도로학회논문집 Vol.25 No.5

PURPOSES : The increase in particulate matter due to increased air pollutant emissions has become a significant social issue. According to the Ministry of Environment, air pollutants emitted from large-scale businesses in 2022 increased by 12.2% compared to the previous year, indicating that air pollution is accelerating owing to excessive industrialization. In this study, TiO2, which is used to reduce airborne particulate, was used. The TiO2 coating fixation and dynamic pressure coating-type TiO2 fixation methods were used to solve the material peeling phenomenon caused by gravity, which is a limitation when the TiO2 penetration method is applied to a vertical concrete structure along the road. The long-term durability and performance were analyzed through environmental resistance and NOx removal efficiency evaluation experiments. These analyses were then assessed by comparing the NOx removal efficiency with the dynamic pressure permeationtype TiO2 fixation method used in previous studies. METHODS : To evaluate the long-term durability and performance of the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation method for vertical concrete structures, specimens were manufactured based on roadside vertical concrete structures. Environmental resistance tests such as the surface peeling resistance test (ASTM C 672) and freeze-thaw resistance test (KS F 2456) were conducted to evaluate the long-term durability. To evaluate the long-term performance, the NOx removal efficiency of TiO2 concrete owing to road surface deterioration during the environmental resistance test was evaluated using the NOx removal efficiency evaluation equipment based on the ISO 22197-1 standard. This evaluation was compared and analyzed using the dynamic pressure infiltration TiO2 fixation method. RESULTS : The long-term durability of the TiO2 coating fixation and dynamic pressure coating TiO2 fixation methods were evaluated using environmental resistance tests. During the surface peeling resistance test, the TiO2 material degraded and partially detached from the concrete. However, the NOx removal efficiency was ensured by the non-deteriorated and fixed TiO2 material. The long-term performance was confirmed through a freeze-thaw resistance test to evaluate the NOx removal efficiency after 300 cycles of surface deterioration. The results showed that when the TiO2 coating fixation and dynamic pressure infiltration TiO2 fixation methods were applied to vertical concrete structures, the durability of the structure was not compromised. In comparison to the dynamic pressure infiltration TiO2 fixation method, the NOx removal efficiency observed during the surface peeling resistance test was lower, while the freeze-thaw test exhibited notably higher removal efficiency. CONCLUSIONS : To solve the material peeling phenomenon caused by gravity, the long-term durability and performance were evaluated by applying the TiO2 coating fixation and dynamic pressurized coating TiO2 fixation methods to vertical concrete specimens. Long-term durability was confirmed through environmental resistance tests, and long-term utility was secured by measuring the NOx removal efficiency according to surface degradation. These findings show that implementing the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation methods on-site effectively reduce NOx.

Synthesis and characterization of TiO2-coated magnetite clusters (nFe3O4@TiO2) as anode materials for Li-ion batteries

Sung-Eun Kim,Kun-Woo Kim,이상화,Sang-Ok Kim,김정섭,이중기 한국물리학회 2013 Current Applied Physics Vol.13 No.9

TiO2-coated magnetite clusters (nFe3O4@TiO2) were facilely prepared through the solegel reaction between Ti alkoxides (TEOT) and magnetite clusters (nFe3O4) with terminated alkoxy groups. The composite particles represented a coreeshell nanostructure (nFe3O4@TiO2) consisting of a Fe3O4 cluster core and a TiO2 capsule layer. The capsule layer of nFe3O4@TiO2 was increased with increasing amounts of TEOT (150, 300, 500 ml) in solegel reaction. The Fe3O4@TiO2 (150 ml of TEOT) with a thin TiO2 layer (ca. 10 nm) exhibited two kinds of cathodic (0.79 V and 1.61 V) and anodic (1.78 and 2.1 V) peaks attributed to the reduction and oxidation process by Fe3O4 core and TiO2 layer, respectively. The thin nFe3O4@TiO2(150 ml of TEOT) exhibited the enhanced capacity retention by ca. 40% probably due to the buffering effect of TiO2 capsule layer. However, the thick nFe3O4@TiO2 (300e500 ml of TEOT) exhibited a rapid capacity fading due to the disintegrated coreeshell nanostructure, i.e., unfavorable hetero-junction between TiO2matrix and magnetite clusters.

Embedding TiO₂ nanoparticles versus surface coating by layer-by-layer deposition on nanoporous polymeric films

Kim, J.,Sotto, A.,Chang, J.,Nam, D.,Boromand, A.,Van der Bruggen, B. Elsevier 2013 Microporous and mesoporous materials Vol.173 No.-

Hybrid polymeric films based on titania (TiO<SUB>2</SUB>) nanoparticles on a polyethersulfone (PES) support were obtained by embedding nanoparticles, by dipping in a single layer and by layer-by-layer assembly. First, TiO<SUB>2</SUB> nanoparticles were doped into a polymeric film during phase-inversion. The permeate flux of TiO<SUB>2</SUB>-embedded membranes in (nano)filtration was higher than for the bare PES membrane in the ultralow concentration range of TiO<SUB>2</SUB> nanoparticles (0.035-0.125wt.%). At the highest concentration of TiO<SUB>2</SUB> nanoparticles tested (0.375wt.%), however, the permeate flux decreased significantly. Compared to the TiO<SUB>2</SUB>-embedded membrane, the permeate flux of TiO<SUB>2</SUB>-deposited membranes prepared by dipping in one single layer was relatively low. After applying layer-by-layer coating, the permeate flux increased considerably as the number of coating layers was increased to >10. SEM images showed that addition of TiO<SUB>2</SUB> nanoparticles during phase inversion resulted in larger finger-like pores in the membrane structure, without changing the surface structure. TiO<SUB>2</SUB>-deposited PES membranes prepared by the layer-by-layer coating proved to have a porous coating layer of TiO<SUB>2</SUB> nanoparticles, covering the surface completely. The surface of TiO<SUB>2</SUB>-deposited films proved to be less rough than that of the bare PES membranes. Release of TiO<SUB>2</SUB> nanoparticles from the membrane surface was not observed during cross-flow filtration, indicative of strong binding of TiO<SUB>2</SUB> nanoparticles on the membrane surface. Similar rejections of humic acid were observed for bare PES membranes and TiO<SUB>2</SUB>-multilayer coated PES membranes, confirming that the membrane structure was not damaged by increasing the number of coating layers of TiO<SUB>2</SUB> nanoparticles on the membrane surface.

Evaluation of Self-cleaning Property by Measuring Brightness of TiO2 Coating Ceramic Tileunder Outdoor Exposure Test

신대용,김경남 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.6

TiO2 coating ceramic tile for self-cleaning purpose was prepared by the precipitant dropping method using TiCl4 as a precursor. TiO2 film was formed on the ceramic tile by spray-coating technique and heat-treated at 500 o C for 1 h. The size and crystalline structure of TiO2 particles were 15.3 nm and anatase phase. The outdoor exposure tests were conducted and the effects of outdoor exposure test conditions, such as exhaust concentration of contamination materials (test places), the UV light intensity (irradiation direction) and coating amounts of TiO2 on the self-cleaning properties were investigated by the brightness measurements. As a results, self-cleaning property of TiO2 coating tile was affected by the coating amount of TiO2, however, not affected by the UV light intensity included in sun's ray (irradiation direction). TiO2 coating ceramic tile can be utilized for exterior finishing materials because of self-cleaning property of TiO2 coating tile. TiO2 coating ceramic tile for self-cleaning purpose was prepared by the precipitant dropping method using TiCl4 as a precursor. TiO2 film was formed on the ceramic tile by spray-coating technique and heat-treated at 500 o C for 1 h. The size and crystalline structure of TiO2 particles were 15.3 nm and anatase phase. The outdoor exposure tests were conducted and the effects of outdoor exposure test conditions, such as exhaust concentration of contamination materials (test places), the UV light intensity (irradiation direction) and coating amounts of TiO2 on the self-cleaning properties were investigated by the brightness measurements. As a results, self-cleaning property of TiO2 coating tile was affected by the coating amount of TiO2, however, not affected by the UV light intensity included in sun's ray (irradiation direction). TiO2 coating ceramic tile can be utilized for exterior finishing materials because of self-cleaning property of TiO2 coating tile.

분무열분해법으로 성장한 Undoped 및 Ca-doped TiO2 박막의 구조와 광학적 특성

서동주,강동완,최성휴 한국물리학회 2010 새물리 Vol.60 No.8

Undoped and Ca-doped TiO2 films were deposited on glass substrates by using spray pyrolysis. The structural properties of films were studied using XRD, SEM, and EDS. Undoped and Ca-doped TiO2 films prepared at a substrate temperature of 450 ˚C were identified as having the tetragonal structure of TiO2 films with a (101) preferred orientation. XRD analysis revealed that the TiO2and the Ca-doped TiO2 films had a tetragonal structure. The optical absorption spectra obtained near the fundamental absorption edge showed that these compounds had direct energy band gaps. The direct energy gaps of TiO2 and Ca-doped TiO2 films (prepared at 450 ˚C) were 3.623 eV and 3.942 eV, respectively. 순수한 TiO2에 Ca을 불순물로 첨가시킨 Ca-doped TiO2 박막을분무열분해법으로 유리기판위에 450˚C온도에서 성장하였다. 성장된 박막을 600˚C에서 2시간 동안 공기 중에서 열처리 후결정구조와 표면형태와 미세구조를 조사하였고, 시료에 대한 박막의광흡수 스펙트럼을 측정하여 광학적 에너지 띠 간격을 구하였다. 열처리한 TiO2 박막 및 Ca-doped TiO2 박막은 (101), (004), (002)면이 성장된 다결정 박막이었으며, tetragonal 구조이고, TiO2 박막은a0 = 3.8372 Å 와 c0 = 9.5153 Å, Ca-doped TiO2박막의 경우 a0 = 3.7762 Å 와 c0 = 9.4643 Å이었다. 기초 흡수단 영역에 측정한 TiO2 박막 및 Ca-doped TiO2 박막은직접전이 밴드 구조이고, 342 nm, 314 nm 영역에서 광흡수 증가가나타났으며, 광학적 에너지 간격은 3.623 eV 와 3.942 eV이었다.

TiO2/ZnS/Ag/ZnS/TiO2 다층막의 PDP 필터용 전극 특성

오원석,이서희,장건익,박성완 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.9

The TiO2/ZnS/Ag/ZnS/TiO2 multilayered structure for the transparent electrodes in plasma display panel was designed by essential macleod program (EMP) and the multilayered film was deposited on a glass substrate by direct-current (DC)/radio-frequency (RF) magnetron sputtering system. During film deposition process, the Ag layer in TiO2/Ag/TiO2 structure became oxidized and the filter characteristic was degraded easily. In this study, ZnS layer was adopted as a diffusion blocking layer between TiO2 and Ag to prevent the oxidation of Ag layer efficiently in TiO2/ZnS/Ag/ZnS/TiO2 structure. Based on the AES depth profiling analysis, the Ag layer was effectively protected by the ZnS layer as compared with the TiO2/Ag/TiO2 multilayered films without ZnS as an antioxidant layer. The 3 times stacked TiO2/ZnS/Ag/ZnS/TiO2 films have low sheet resistance of 1.22 Ω/□ and luminous transmittance was as high as 62% in the visible ranges.

TiO₂Interlayer의 상변화에 따른 PLZT 박막의 구조 및 전기적 특성

손영국,윤지언,황동현,차원효,이철수 한국진공학회 2007 Applied Science and Convergence Technology Vol.16 No.6

(Pb1.1,La0.08)(Zr0.65.Ti0.35)O3 thin films on the Pt/Ti/SiO2/Si, TiO2(interlayer)/Pt/Ti/SiO2/Si substrate were fabricated by the R.F. magnetron-sputtering method and considered their characteristics depending on TiO2 interlayer. Changing the deposition conditions of TiO2 interlayer, we obtained TiO2 anatase single phase and rutile single phase. PLZT was deposited on these substrates and analyzed by x-ray diffraction(XRD) for there crystallinity and orientation. To investigate PLZT-TiO2, TiO2-Pt interface, glow discharge spectrometer(GDS) analysis was carried out and we performed electrical measurements for dielectric properties of PLZT thin films. The PLZT thin film on TiO2 anatase interlayer was found to have (110)-preferred orientation and 12.6 μC/cm2 remaining polarization value. KeyWords:PLZT, RF magnetron sputtering, TiO2 interlayer R.F. magnetron-sputtering 방법에 의해 (Pb1.1,La0.08)(Zr0.65.Ti0.35)O3 박막을 Pt/Ti/SiO2/Si, TiO2(interlayer)/Pt/Ti/SiO2/Si 기판에 증착하고, TiO2 interlayer에 의한 PLZT 박막의 특성을 고찰 하였다. TiO2 interlayer의 증착조건을 변화시켜가며 단일상의 anatase 상과 rutile 상을 증착하였고, 그 위에 증착시킨 PLZT 박막의 결정성을 x-ray diffraction(XRD)을 통해 분석하였다. 또한 TiO2 interlayer에 의한 PLZT-TiO2, TiO2-Pt 박막의 계면상태를 고찰하기 위해 glow discharge spectrometer(GDS) 분석을 행하였고, PLZT의 강유전 특성을 고찰하기 위해 전기적 측정을 행하였다. TiO2 anatase 단일 상에 증착한 PLZT의 경우 (110) 방향으로 우선 배향됨을 알 수 있었고, 12.6 μC/cm2의 잔류분극 값을 나타내었다.

TiO2 콘크리트의 표면열화에 따른 질소산화물(NOx) 제거효율 평가

안희락,김영규,이승우 한국도로학회 2022 한국도로학회논문집 Vol.24 No.2

PURPOSES : Recently, air pollution caused by particulate matter has been worsening. Among the substances generating particulate matter, NOx is the main precursor of particulate matter and is widely distributed in areas with a high volume of traffic. TiO2 has been used as a material for removing NOx through a chemical reaction as a photocatalyst. In this context, the reduction of NOx through TiO2 concrete is proposed. However, the research on the surface deterioration on the performance of TiO2 concrete is not documented yet. Therefore, the objective of this study was to evaluate the long-term durability and NOx removal efficiency of TiO2 concrete by considering the concrete surface deterioration. METHODS : Freezing–thawing resistance test (KS F 2456) and scaling test (ASTM C 672) were performed to investigate the variation in the TiO2 penetration distribution and NOx removal efficiency of TiO2 concrete corresponding to surface deterioration. The long-term durability of TiO2 concrete was evaluated through an environmental resistance test and changes in TiO2 penetration depth and distribution characteristics. In addition, the NOx removal efficiency of TiO2 concrete was evaluated as surface deterioration occurs. RESULTS : As a result of the freeze–thawing resistance test, a relative dynamic elastic modulus of more than 80 % was detected. In addition, a TiO2 penetration depth of 0.3 mm, NOx removal efficiency of 11.2 %, and a 30 % of TiO2 surface prediction mass ratio were achieved after 300 cycles. As a result of visual observation of the scaling test, “0, no scaling” was secured. After 50 cycles of scaling test, the TiO2 penetration depth, NOx removal efficiency, and TiO2 surface prediction mass ratio were 0.3 mm, 36.3 %, and 63 %, respectively. Through the results of the environmental resistance test, the excellent long-term durability and NOx removal efficiency of TiO2 concrete were confirmed. CONCLUSIONS : As a result of the experiment, long-term durability and NOx removal efficiency of TiO2 concrete were secured. The application of TiO2 concrete can be a good alternative with long-term performance and durability.