• 제목/요약/키워드: Fluorescence Materials

검색결과 504건 처리시간 0.025초

Nitric Oxide Detection of Fe(DTC)3-hybrizided CdSe Quantum Dots Via Fluorescence Energy Transfer

  • Chang-Yeoul, Kim
    • 한국분말재료학회지
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    • 제29권6호
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    • pp.453-458
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    • 2022
  • We successfully synthesize water-dispersible CTAB-capped CdSe@ZnS quantum dots with the crystal size of the CdSe quantum dots controlled from green to orange colors. The quenching effect of Fe(DTC)3 is very efficient to turn off the emission light of quantum dots at four molar ratios of the CdSe quantum dots, that is, the effective covering the surface of quantum dots with Fe(DTC)3. However, the reaction with Fe(DTC)3 for more than 24 h is required to completely realize the quenching effect. The highly quenched quantum dots efficiently detect nitric oxide at nano-molar concentration of 110nM of NO with 34% of recovery of emission light intensity. We suggest that Fe(DTC)3-hybridized CdSe@ZnS quantum dots are an excellent fluorescence resonance energy transfer probe for the detection of nitric oxide in biological systems.

Highly Fluorescing Solid DNA-Cationic Polyelectrolyte Complexes Prepared from a Natural DNA and a Poly(fluorenevinylene-alt-phenylene) Bearing Quaternary Ammonium Pendants

  • Yu, Young-Jun;Kwon, Young-Wan;Kim, Kyu-Nam;Do, Eui-Doo;Choi, Dong-Hoon;Jin, Jung-Il;Shin, Hee-Won;Kim, Yong-Rok;Kang, Ik-Joong;Mikroyannidis, John A.
    • Macromolecular Research
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    • 제17권4호
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    • pp.245-249
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    • 2009
  • A fluorescing, copolymer(Q)-bearing, quaternary ammonium pendant was mixed with excess natural salmon sperm DNA with a molecular weight of $1.3{\times}10^6$(2,000 base pairs) to afford highly fluorescing, complex mixtures. The fluorescence life-time of the polymer Q was greatly increased when mixed with DNA: for the mixture of Q:DNA=1:750 the fast and slow decay lifetimes increased from ca. 10 to 100 ps and from 20 ps to ca. 1 ns, respectively. The enhanced fluorescence of the mixtures was ascribed to efficient compartmentalization and reduced conformational relaxation of the polymer Q by complexation with excess DNA.

선량과 선질에 따른 형광량계 응답특성 (The Response of Fluorescence Meter according to X-ray dose and quality)

  • 김정민;김명준;윤종민
    • 대한방사선기술학회지:방사선기술과학
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    • 제18권1호
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    • pp.71-75
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    • 1995
  • In order to establish the photographic effects and sensitivity of various screens, fluorescence meter is used with convenience. When the radiation quality has been fixed the fluorescence has increased in proportion to X-ray dose. However, the response of fluorescence meter has the dependency of X-ray quality in accordance with KVP. as well as the difference of screen and scatter fraction can influence on the response of fluorescence meter. Using accurate fluorescence meter as a radiation detecter and as for a proper supervision the sensitive materials, we have to aware of the meter's dependency of X-ray quality and the scatter fraction.

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Miniaturized Fluorometer Based on Total Internal Reflector and Condensing Mirror

  • Jang, Dae-Ho;Yoo, Jae-Chern
    • Journal of the Optical Society of Korea
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    • 제17권1호
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    • pp.81-85
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    • 2013
  • A miniaturized fluorescence detection system based on total internal reflection (TIR) configuration, which is applicable to detecting the presence of biological materials labeled with fluorescence dye in micro total analysis systems (${\mu}TAS$), is proposed. In conventional fluorescence testing and analysis devices, interference between the excitation light beam and the emitted light from dyes is unavoidable. This paper presents a fluorescence detection system based on TIR configuration that allows the excitation light beam and the emitted light to be spatially perpendicular to each other so as to minimize the interference where fluorescence emission is detected at the orthogonal angle to the excitation beam. We achieved the limit of detection of about 5 nmol/L with a high linearity of 0.994 over a wide range of 6-FAM mol concentration, being comparable to that in earlier studies.

Fluorescence-Quenched Sensor for Trinitophenol in Aqueous Solution Based on Sulfur Doped Graphitic Carbon Nitride

  • Min, Kyeong Su;Manivannan, Ramalingam;Satheshkumar, Angu;Son, Young-A
    • 한국염색가공학회지
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    • 제30권2호
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    • pp.63-69
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    • 2018
  • In this study, we report on successful attempt towards the synthesis of sulfur self-doped $g-C_3N_4$ by directly heating thiourea in air. The synthesized materials were characterized using UV-vis spectral technique, FT-IR, XRD and TEM analysis. Further, the obtained material shows an excellent detection of carcinogenic TNP(Tri nitro phenol) in the presence of 10-fold excess of various other common interferences. The strong inner filter effect and molecular interactions(electrostatic, ${\pi}-{\pi}$, and hydrogen bonding interactions) between TNP and the $S-g-C_3N_4$ Nano sheets led to the fluorescence quenching of the $S-g-C_3N_4$ Nano sheets with an excellent selectivity and sensitivity towards TNP compared to that of other nitro aromatics under optimal conditions and the detection limit calculated was found to be 6.324 nM for TNP. The synthesized nanocomposite provides a promising platform for the development of sensors with improved reproducibility and stability for ultra-sensitive and selective sensing of TNP.

Fluorescence Switching of Conjugated Polyelectrolyte based on Polydiphenylacetylene

  • Lee, W.E.;Kim, J.H.;Sakaguchi, T.;Kwak, G.;Lee, C.L.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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    • pp.245.1-245.1
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    • 2013
  • Polydiphenylacetylene (PDPA) derivatives are a class of conjugated polymer that contain intramolecular excimer emission originating the intramolecular stack structure. In contrast with conventional conjugated polymer, the fluorescence property of PDPA significantly depends on the intramolecular stack structure. In this regard, herein, we investigated new fluorescence switching mechanism of conjugated polyelectrolyte (CPE) based on PDPA. The developed CPE showed relatively weak fluorescence emission in water, while the polymer exhibited a great fluorescence amplification behavior by electrostatic complex with proteins. In addition, the CPE is highly sensitive to binding with a little protein despite of turn-on type fluorescence response. We found that the fluorescence switching of the CPE closely relate to a perturbation of the intramolecular stack structure. The new fluorescence switching mechanism of the CPE is very useful for protein assays and discrimination and it also would be provide new sensing approaches as basic sensing mechanism.

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OLED용 지연형광 소재의 연구 동향 (Research Trends of Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes)

  • 이주영
    • 세라미스트
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    • 제22권3호
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    • pp.218-229
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    • 2019
  • The development of highly efficient thermally activated delayed fluorescence (TADF) materials is an active area of recent research in organic light emitting diodes (OLEDs) since the first report by Chihaya Adachi in 2011. Traditional fluorescent materials can harvest only singlet excitons, leading to the theoretically highest external quantum efficiency (EQE) of 5% with considering about 20% light out-coupling efficiency in the device. On the other hand, TADF materials can harvest both singlet and triplet excitons through reverse intersystem crossing (RISC) from triplet to singlet excited states. It could provide 100% internal quantum efficiencies (IQE), resulting in comparable high EQE to traditional rare-metal complexes (phosphorescent materials). Thanks to a lot of efforts in this field, many highly efficient TADF materials have been developed. This review focused on recent molecular design concept and optoelectronic properties of TADF materials for high efficiency and long lifetime OLED application.

Green Synthesis of Multifunctional Carbon Nanodots and Their Applications as a Smart Nanothermometer and Cr(VI) Ions Sensor

  • Li, Lu;Shao, Congying;Wu, Qian;Wang, Yunjian;Liu, Mingzhu
    • Nano
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    • 제13권12호
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    • pp.1850147.1-1850147.14
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    • 2018
  • In this work, water-soluble and blue-emitting carbon nanodots (CDs) were synthesized from apple peels for the first time via one-step hydrothermal method. The synthetic route is facile, green, economical and viable. The as-prepared CDs were characterized thoroughly by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, Fourier transform infrared (FT-IR), X-ray photoelectron (XPS), fluorescence and UV-Vis absorption spectroscopy in terms of their morphology, surface functional groups and optical properties. The results show that these CDs possessed ultrasmall size, good dispersivity, and high tolerance to pH, ionic strength and continuous UV irradiation. Significantly, the CDs had fast and reversible response towards temperature, and the accurate linear relationship between fluorescence intensity and temperature was used to design a novel nanothermometer in a broad temperature range from 5 to $65^{\circ}C$ facilely. In addition, the fluorescence intensity of CDs was observed to be quenched immediately by Cr(VI) ions based on the inner filter effect. A low-cost Cr(VI) ions sensor was proposed employing CDs as fluorescent probe, and it displayed a wide linear range from 0.5 to $200{\mu}M$ with a detection limit of $0.73{\mu}M$. The practicability of the developed Cr(VI) sensor for real water sample assay was also validated with satisfactory recoveries.

Excited-State Intramolecular Proton Transfer (ESIPT) Fluorescence in a Polymeric System

  • Park, Soo-Young
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.35-36
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    • 2006
  • Excited-state intramolecular proton transfer (ESIPT) is a phototautomerization occurring in the excited states of the molecules possessing a cyclic intramolecular or solvent-bridged hydrogen bond. Recently, we have developed novel ESIPT chromophores, molecules, dendrimers and polymers which show very high fluorescence quantum efficiency combined with the characteristic features of optical switching, fluorescence patterining, lasing, and electroluminescence. Broad overview of these topics will be given in this talk.

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