• 공업화학
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• 제21권4호
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• pp.357-365
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• 2010

신약개발 과정에서 선도물질을 도출하기 위한 유용한 방법으로 적용되어온 조합합성은 최근 분석과 검사 기술의 빠른 발전과 더불어 다양한 분야에서 응용되고 있다. 특히 분자구조와 특성 간의 상관관계를 예측하기 어려운 신물질 개발 분야에서 다양한 후보 물질들을 빠른 시간 내에 확보하기 위한 효율적인 전략으로 주목받고 있다. 그 동안 조합화학 및 조합합성 기법에 관하여 많은 수의 보고서와 총설들이 발표되었다. 본 총설에서는 조합합성을 이용한 신소재 개발 동향을 간략히 소개하고, 이를 응용한 유기발광재료 개발 사례들을 논의하고자 한다.

• Advances in nano research
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• 제4권2호
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• pp.113-128
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• 2016

Luminescent metallic clusters have attracted great interest due to their unique optical, electronic and chemical features. Comparing with intensively studied Au and Ag Clusters, Cu clusters are superior in the aspects of cost and wide industrial demanding. However, tiny copper clusters are extremely prone to aggregate and undergo susceptibility of oxidation, thereby the synthesis of fluorescent zero valent copper clusters is rather challenging. In this review, synthetic strategies towards luminescent copper clusters, including macromolecule-protection and micro molecule-capping, have been systematically surveyed. Both "bottom-up" and "top-down" synthetic routes are found to be effective in fabricating luminescent copper clusters, some of which are quite stable and possess decent luminescence quantum yields. In general, the synthesis of fluorescent copper clusters remains at its infant stage. A great deal of effort on developing novel and economic synthetic routes to produce bright and stable copper clusters is highly expected in future.

• 한국분말재료학회지
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• 제25권2호
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• pp.170-177
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• 2018

Colloidally synthesized luminescent nanocrystals (NCs) have attracted tremendous attention due to their unique nanoscale optical and electronic properties. The emission properties of these NCs can be precisely tuned by controlling their size, shape, and composition as well as by introducing appropriate dopant impurities. Nowadays, these NCs are actively utilized for various applications such as optoelectronic devices including light emitting diodes (LEDs), lasers, and solar cells, and bio-medical applications such as imaging agents and bio-sensors. In this review, we classify luminescent nanomaterials into quantum dots (QDs), upconversion nanoparticles (UCNPs), and perovskite NCs and present their intrinsic emission mechanism. Furthermore, the recently emerging issues of efficiency, toxicity, and durability in these materials are discussed for better understanding of industry demands. As well, the future outlook will be offered for researchers to guide the direction of future research.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.52-55
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• 2009

A red phosphor, $(Sr,Ca)_2P_2O_7:Eu^{2+},Mn^{2+}$, for UV-LED was synthesized under a reducing atmosphere, and its luminescent properties were investigated. The phosphor absorbs ultraviolet light at around 400 nm and efficiently emits red light at approximately 610 nm through an energy transfer from $Eu^{2+}$ to $Mn^{2+}$. Using the varied input current test for the phosphor-loaded LED lamps, it was found that the luminescent efficiency of the phosphor decreased with increasing light flux. This might be due to an increased probability of excited-state absorption and the consequent non-radiative relaxation in $Mn^{2+}$ ions in the condition of high photon influx.

• 한국재료학회지
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• 제27권6호
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• pp.301-306
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• 2017

The discovery of new luminescent materials for use in light-emitting diodes(LEDs) has been of great interest, since LED-based solid state lighting applications are attracting a lot of attention in the energy saving and environmental fields. Recent research trends have centered on the discovery of new luminescent materials rather than on fine changes in well-known luminescent materials. In a sense, the novelty of our study beyond simple modification or improvement of existing phosphors. A good strategy for the discovery of new fluorescent materials is to introduce activators that are appropriate for conventional inorganic compounds, that have well-defined structures in the crystal structure database, but have not been considered as phosphor hosts. Another strategy is to discover new host compounds with structures that cannot be found in any existing databases. We have pursued these two strategies at the same time using composite search technology with particle swarm optimization(PSO). In this study, using PSO, we have tracked down a search space composed of Sr-Al-Si-O-N and have discovered a new phosphor structure with yellow luminescence; this material is a potential candidate for UV-LED applications.

• 한국재료학회지
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• 제23권12호
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• pp.727-731
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• 2013

In this study, green barium strontium silicate phosphor ($BaSrSiO_4:Eu^{3+}$, $Eu^{2+}$) was synthesized using a solid-state reaction method in air and reducing atmosphere. Investigation of the firing temperature indicates that a single phase of $BaSrSiO_4$ is formed when the firing temperature is higher than $1400^{\circ}C$. The effect of firing temperature and doping concentration on luminescent properties are investigated. The light-emitting property was the best when the molar content of $Eu_2O_3$ was 0.025 mol. Also, the luminescent brightness of the $BaSrSiO_4$ fluorescent substance was the best when the particle size of the barium was $0.5{\mu}m$. $BaSrSiO_4$ phosphors exhibit the typical green luminescent properties of $Eu^{3+}$ and $Eu^{2+}$. The characteristics of the synthesized $BaSrSiO_4:Eu^{3+}$, $Eu^{2+}$ phosphor were investigated using X-ray diffraction (XRD) and scanning electron microscopy. The maximum emission band of the $BaSrSiO_4:Eu^{3+}$, $Eu^{2+}$ was 520 nm.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.204-206
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• 2009

Luminescent films were prepared by infiltration of tris(dibenzoylmethane) mono(1, 10-phenanthroline) europium incorporated ormosil into colloidal $SiO_2$ photonic crystal templates. The PL intensity of the infiltrated film into the template was about 13 times higher than that of the plane film prepared without the template.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3109-3112
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• 2009

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.360.1-360.1
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• 2016

Hydroxyapatite (Ca10(PO4)6(OH)2, HAP) particles have attracted a great deal of attention in biomedical fields due to their good biocompatibility, bioactivity and fairly broad applications as drug delivery, dental implant, bone cement, and etc. Thus, many researchers have made an effort to add new functionalities such as luminescence, drug delivery, and bone regeneration properties up to HAP powders by controlling their nanostructure as well as composition. In this research, the mesoporous strontium substituted HAP (Sr-HAP) microspheres were synthesized using a hydrothermal method. In this synthesis, aspartic acid monomers were utilized to form microsphere by controlling surface energy of HAP particles and Sr ions were substituted into Ca ion sites, which induced luminescence property in HAP powders. Moreover, the change in the amount of Sr substitution was found to influence the particle size, morphology, and concurrently surface area, which led to changing drug loading as well as drug release property. The amount of Sr influences the morphology, luminescent properties, particle size, surface area cell viability and drug loading property, which are investigated by SEM, TEM, XRD, FTIR, BET, XPS and in vitro test such as MTT assay and drug release test. In particular, the multifunctional Sr-HAP with molar ratios of 0.25 (Sr/(Ca+Sr)) possessed the strongest luminescent property as well as the superior drug loading and sustained release properties that were correspondent with large surface area and pore size. Our study indicates that the fabricated multifunctional Sr-HAP microspheres are quite useful for bone regeneration and drug delivery.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1534-1535
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• 2005

Highly luminescent efficiency phosphors have been successfully produced by surface modification and microwave irradiation treatment. The SEM image and XRD analysis reveal that the surface morphology of the white-light phosphors can be notably modified by microwave irradiation and exhibit with better crystalline property. The VUV PL spectra show that the microwave irradiation treatment can effectively enhance the luminescent efficiency by a factor of 1.5 times for intensity compared to that without microwave treatment. A further improvement in all visible emission can be made by modifying surface composition through MgO coating on the phosphor powder. These results demonstrate that such a simple approach can provide for improving luminescent efficiency of phosphors for the optoelectronic devices.