Core/shell CdSe/ZnS quantum dots (QDs) are synthesized by a microfluidic reactor-assisted continuous reactor system. Photoluminescence and absorbance of synthesized CdSe/ZnS core/shell QDs are investigated by fluorescence spectrophotometry and online UV-Vis spectrometry. Three reaction conditions, namely; the shell coating reaction temperature, the shell coating reaction time, and the ZnS/CdSe precursor volume ratio, are combined in the synthesis process. The quantum yield of the synthesized CdSe QDs is determined for each condition. CdSe/ZnS QDs with a higher quantum yield are obtained compared to the discontinuous microfluidic reactor synthesis system. The maximum quantum efficiency is 98.3% when the reaction temperature, reaction time, and ZnS/CdSe ratio are 270℃, 10 s, and 0.05, respectively. Obtained results indicate that a continuous synthesis of the Core/shell CdSe/ZnS QDs with a high quantum efficiency could be achieved by isolating the reaction from the external environment.

In this study, simple chemical synthesis of green emitting Cd-free InP/ZnS QDs is accomplished by reacting In, P, Zn, and S precursors by one-pot process. The particle size and the optical properties were tailored, by controlling various experimental conditions, including [In]/[MA] (MA: myristic acid) mole ratio, reaction temperature and reaction time. The results of ultraviolet–visible spectroscopy (UV-vis), and of photoluminescence (PL), reveal that the exciton emission of InP was improved by surface coating, with a layer of ZnS. We report the correlation between each experimental condition and the luminescent properties of InP/ZnS core/shell QDs. Transmission electron microscopy (TEM), and X-ray powder diffraction (XRD) techniques were used to characterize the as-synthesized QDs. In contrast to core nanoparticles, InP/ZnS core/shell treated with surface coating shows a clear ultraviolet peak. Besides this work, we need to study what clearly determines the shell kinetic growth mechanism of InP/ZnS core shell QDs.

A microfluidic reactor with computer-controlled programmable isocratic pumps and online detectors is employed as a combinatorial synthesis system to synthesize and analyze materials for fabricating CdSe quantum dots for various applications. Four reaction condition parameters, namely, the reaction temperature, reaction time, Cd/Se compositional ratio, and precursor concentration, are combined in synthesis condition sets, and the size of the synthesized CdSe quantum dots is determined for each condition. The average time corresponding to each reaction condition for obtaining the ultraviolet–visible absorbance and photoluminescence spectra is approximately 10 min. Using the data from the combinatorial synthesis system, the effects of the reaction conditions on the synthesized CdSe quantum dots are determined. Further, the data is used to determine the relationships between the reaction conditions and the CdSe particle size. This method should aid in determining and selecting the optimal conditions for synthesizing nanoparticles for diverse applications.

Flat panel display devices are mainly used as information display devices in the 21st century. The worldwide waste flat panel displays are expected at 2-3 million units but most of them are land-filled for want of a proper recycling technology More specifically, rare earth metals of La and Eu are used as fluorescent materials of Cold Cathode Flourscent Lamp(CCFL)s in the waste flat panel displays and they are critically vulnerable and irreplaceable strategic mineral resources. At present, most of the waste CCFLs are disposed of by land-filling and incineration and proper recovery of 80-plus tons per annum of the rare earth fluorescent materials will significantly contribute to steady supply of them. A dearth of Korean domestic research results on recovery and recycling of rare earth elements in the CCFLs prompts to initiate this status report on overseas research trends and noteworthy research results in related fields.

Leaching of MOCVD dust in the LED industry is an essential stage for hydro-metallurgical recovery of pure Ga and In. To recover Ga and In, the leaching behavior of MOCVD scrap of an LED, which contains significant amounts of Ga, In, Al and Fe in various phases, has been investigated. The leaching process must be performed effectively to maximize recovery of Ga and In metals using the most efficient lixiviant. Crystalline structure and metallic composition of the raw MOCVD dust were analyzed prior to digestion. Subsequently, various mineral acids were tested to comprehensively study and optimize the leaching parameters such as acidity, pulp density, temperature and time. The most effective leaching of Ga and In was observed for a boiling 4 M HCl solution vigorously stirred at 400 rpm. Phase transformation of GaN into gallium oxide by heat treatment also improved the leaching efficiency of Ga. Subsequently high purity Ga and In can be recovered by series of hydro processes.

Nano-sized cobalt powder was fabricated by wet chemical reduction method at room temperature. The effects of various experimental variables on the overall properties of fabricated nano-sized cobalt powders have been investigated in detail, and amount of NaOH and reducing agent and dropping speed of reducing agent have been prop- erly selected as experimental variables in the present research. Minitab program which could find optimized conditions was adopted as a statistic analysis. 3D Scatter-Plot and DOE (Design of Experiments) conditions for synthesis of nano- sized cobalt powder were well developed using Box-Behnken DOE method. Based on the results of the DOE process, reproducibility test were performed for nano-sized cobalt powder. Spherical nano-sized cobalt powders with an average size of 70-100 nm were successfully developed and crystalline peaks for the HCP and FCC structure were observed without second phase such as Co(OH).

Nowadays, research and development on quantum dot have been intensively and comprehensively pursued worldwide in proportion to concurrent breakthrough in the field of nanotechnology. At present, quantum dot technology forms the main interdisciplinary basis of energy, biological and photoelectric devices. More specifically, quantum dot semiconductor is quite noteworthy for its sub-micro size and possibility of photonic frequency modulation capability by controlling its size, which has not been possible with conventionally fabricated bulk or thin film devices. This could lead to realization of novel high performance devices. To further understand related background knowledge of semiconductor quantum dot at somewhat extensive level, a review paper is presently drafted to introduce basics of (semiconductor) quantum dot, its properties, applications, and present and future market trend and prospect.

Mass production-capable powder was synthesized for use as cathode material in state-of-the-art lithium-ion batteries. These batteries are main powder sources for high tech-end digital electronic equipments and electric vehicles in the near future and they must possess high specific capacity and durable charge-discharge characteristics. Amorphous silicone was quite superior to crystalline one as starting material to fabricate silicone oxide with high reactivity between precursors of sol-gel type reaction intermediates. The amorphous silicone starting material also has beneficial effect of efficiently controlling secondary phases, most notably . Lastly, carbon was coated on powders by using sucrose to afford some improved electrical conductivity. The carbon-coated cathode material was further characterized using SEM, XRD, and galvanostatic charge/discharge test method for morphological and electrochemical examinations. Coin cell was subject to 1.5-4.8 V at C/20, where 74 mAh/g was observed during primary discharge cycle.

Spherical nanosized cobalt powder with an average size of 150-400 nm was successfully prepared at room temperature from cobalt sulfate heptahydrate (). Wet chemical reduction method was adopted to synthesize nano cobalt powder and hypophosphorous acid () was used as reduction agent. Both the HCP and the FCC Co phase were developed while concentration ranged from 0.7 M to 1.1 M. Secondary phase such as and were also observed. Peaks for the crystalline Co phase having HCP and FCC structure crystallized as increasing the concentration of , indicating that the amount of reduction agent was enough to reduce . Consequently, a homogeneous Co phase could be developed without second phase when the ratio exceeded 7.

액정 디스플레이는 가벼운 무게, 작은 부피, 낮은 비용, 낮은 전력 소비 등의 이유로 PC 모니터, 노트북, 태블릿 등 광범위한 분야에서 사용되며 원료 사용량이 증가하게 되었다. 우수한 광전자 특성으로 인하여 액정 디스플레이에서 투명 전도 산화물 박막으로 indium-tin-oxide(ITO)가 사용된다. ITO는 90 wt%의 In2O3와 10 wt%의 SnO2로 이루어져 있으며 전세계 인듐 소비량의 84%는 액정 디스플레이 제조시 ITO를 형성하는데 사용된다. 일반적으로 3-8년인 액정 디스플레이의 수명을 고려하면, LCD의 폐기물은 재활용을 통하여 인듐을 생산 할 수 있는 잠재적인 대체 자원이다. 액정 디스플레이 재활용을 통하여 소각 또는 매립되는 폐기물로 인한 환경오염을 방지 할 수 있으며 또한 폐기물 내 인듐과 같은 유가금속을 재활용 하여 부가가치를 창출 할 수 있어 폐 액정디스플레이 재활용은 도시 광산 분야의 중요한 연구의 분야이다. 본 연구기관에서는 수명이 다한 사용 후 LCD TV를 해체/분리하여 액정패널, 인쇄회로기판, 냉음극관, 플라스틱케이스, 금속류 등으로 분해 하는 공정을 개발하였다. 해체/분리 공정을 통해 분리된 액정패널은 기계적으로 파쇄를 하여 유리 입자사이즈를 작게 하여 이 후 금속 회수를 용이하게 하였다. 본 연구에서는 파쇄 된 액정 디스플레이 유리에서 인듐을 회수하기 위하여 산을 이용하여 용출을 하였다. 가능한 용출 변수를 실험을 통하여 최적화 하였다. 액정 디스플레이에 인듐 함유량이 매우 낮아 특별히 고안된 방법을 이용하여 침출 용액을 농축하였으며 최적의 조건에서 인듐이 완전히 용출되는 것을 확인 할 수 있었다. 또한, 인듐 외 다른 금속에 대한 용출을 최소화 하였다.

국내 폐 디스플레이 발생량은 2015년 157만대 정도 규모에서 2025년 1,123만대 정도로 약 7배 이상 증가할 것으로 예상되고 있다. 하지만 현재 폐 디스플레이 재활용 기술 개발은 제품을 구성하는 단일부품에 대해 일부만 진행 중에 있다. 디스플레이를 구성하는 금속, 필름/시트, LCD 패널, 플라스틱, PCB, CCFL, 전선 등으로부터 유가자원을 회수하고, 이를 소재화하는 것은 경제 및 환경적으로 매우 중요한 산업임에도 불구하고, 폐 제품을 부품 종류별로 최종 재활용 업체에 선별 납품하는 폐 디스플레이 분리/해체 플랜트 구축 현황은 국가적으로 매우 미흡한 실정이다. 현재 국내에서 폐 디스플레이 제품의 각 모듈별 분해과정은 재활용 센터를 중심으로 이루어지고 있으나, 디스플레이 제조사 및 모델별 구성 부품과 나사 위치가 달라서 수작업을 통해 공정을 진행하는데 많은 애로사항이 있으므로 분해공정에 있어서 제품별 정보인식/제공과 자동화 기술 도입을 통해 작업 효율을 높일 필요성이 있다. 본 발명의 핵심은 스마트 인식 장치를 이용하여 폐 디스플레이의 모델을 빠른 속도로 판별하고 후단의 공정에 필요한 데이터를 제공하는 것으로 정확한 폐 디스플레이의 모델 인식이 가능하도록 하고 각각의 공정에 필요한 정보를 제공하여 폐 디스플레이 해체 및 선별 작업의 효율성을 극대화 시키고 생산성을 향상시키는데 있다.