• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1061-1064
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• 2013

A known $Hg^{2+}$ selective rhodamine B derivatised probe 1 was reinvestigated as a colorimetric and fluorescent probe for $Cu^{2+}$ through changing the applied solvent media. Probe 1 exhibited good selectivity and sensitivity to $Cu^{2+}$ in $CH_3CN-H_2O$ (7:3, v/v, HEPES 10 mM, pH 7.0) solution with a detection limit of $9.74{\times}10^{-7}$ M. The $Cu^{2+}$ sensing event was proved to be irreversible through hydrolysis of 1 to release rhodamine B.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3696-3700
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• 2012

The colorimetric and fluorescent cyanide recognition properties of 2-[(9-ethyl-9H-carbazol-3-yl)methylene]-propanedinitrile (1) in $CH_3CN-H_2O$ (2/1, v/v, HEPES 10 mM, pH = 7.0) solution were evaluated. The optical recognition process of probe 1 exhibited high sensitivity and selectivity to cyanide ion with the detection limit of $2.04{\times}10^{-6}$ M and barely interfered by other coexisting anions. The sensing mechanism of probe 1 is speculated to undergo a nucleophilic addition of cyanide to dicyanovinyl group present in compound 1. The colorimetric and fluorescent dual-modal response to cyanide makes probe 1 has a potential utility in cyanide detection.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2359-2364
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• 2012

Two new chemosensors, rhodamine 6G derivative bearing hydroxyethyl group (1) and rhodamine base derivative bearing 15-crown-5 group (2) were synthesized and their sensing behaviors toward various metal ions were investigated by UV/Vis and fluorescence spectroscopies. Addition of $Hg^{2+}$ ion to a $CH_3CN$ solution of 1 and 2 gave visual color changes as well as fluorescent OFF-ON observations. Selectivity and sensitivity of 1 towards $Hg^{2+}$ are excellent enough to detect micromolar level of $Hg^{2+}$ ion, even in equeous media and biological sample (HeLa cell).

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2735-2738
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• 2009

A simple colorimetric anion chemosensor based on 2-amino-6-nitrobenzothiazole was synthesized. The addition of tetrabutylammonium (TBA) salts of $F^-,\;{CH_3COO}^-,\;and\;{H_2PO_4}^-$ to the solution of receptor 3 caused dramatic and clearly observable color changes from light to dark yellow due to the deprotonation process which is totally different from previously reported receptors based on the same motif. According to the basicity of the anions, the sensitivity of receptor 3 towards various anions decreased in the following order: ${CH_3COO}^-\;>\;F^-\;>\;{H_2PO_4}^-$.

• 대한화학회지
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• 제18권1호
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• pp.47-49
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• 1974

감광트랜지스터 끝에 렌즈를 부착시켜 지향성을 충분히 좋게 한 것을 유리관 끝에 접착 밀봉하여 광도 검지기를 만들었다. 적정용액속에 이 감지기를 수직으로 담거 세우고, 밑에서 빛을 쪼여 올리면서 적정하는 방법을 발전시켜, 밝은 실험실에서 흡광광도 적정을 실시할 수 있게 하였다.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.79-86
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• 2018

Although the intrinsic characteristics of DNA molecules and carbon nanotubes (CNT) are well known, fabrication methods and physical characteristics of CNT-embedded DNA thin films are rarely investigated. We report the construction and characterization of carboxyl (-COOH) group-modified multi-walled carbon nanotube (MWCNT-COOH)-embedded DNA and cetyltrimethyl-ammonium chloride-modified DNA (DNA-CTMA) composite thin films. Here, we examine the structural, compositional, chemical, spectroscopic, and electrical characteristics of DNA and DNA-CTMA thin films consisting of various concentrations of MWCNT-COOH. The MWCNT-COOH-embedded DNA and DNA-CTMA composite thin films may offer a platform for developing novel optoelectronics, energy harvesting, and sensing applications in physical, chemical, and biological sciences.

• 통합자연과학논문집
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• 제4권1호
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• pp.7-10
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• 2011

Various types of smart dust based on photonic crystal exhibiting unique reflectivity were successfully obtained by an electrochemical etching of silicon wafer using square wave currents. Smart dust containing Bragg structure obtained from the sonication of DBR porous silicon film in solution retained its optical reflectivity. Field emission scanning electron micrograph (FE-SEM) was used to measure the size of optically encoded smart dust and its size can be tuned from few hundred nanometers to few microns depending on the duration of sonication. Optical characteristics of smart dust were used to investigate a possible applications such as chemical sensors.

• Journal of information and communication convergence engineering
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• 제17권1호
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• pp.49-59
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• 2019

Biosensors, which are analysis devices used to convert biological reactions into electric signals, are made up of a receptor component and a signal transduction part. Graphene quantum dots (GQDs) and carbon quantum dots (CQDs) are new types of carbon nanoparticles that have drawn a significant amount of attention in nanoparticle research. The unique features exhibited by GQDs and CQDs are their excellent fluorescence, biocompatibility, and low cytotoxicity. As a result of these features, carbon nanomaterials have been extensively studied in bioengineering, including biosensing and bioimaging. It is extremely important to find biomaterials that participate in biological processes. Biomaterials have been studied in the development of fluorescence-based detection methods. This review provides an overview of recent advances and new trends in the area of biosensors based on GQDs and CQDs as biosensor platforms for the detection of biomaterials using fluorescence. The sensing methods are classified based on the types of biomaterials, including nucleic acids, vitamins, amino acids, and glucose.

• 센서학회지
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• 제13권5호
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• pp.323-328
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• 2004

N-type semi-conducting oxides such as $SnO_{2}$, ZnO, and $ZrO_{2}$ have been known for the detecting materials of inflammable or toxic gases. Of those materials, $SnO_{2}$-based sensors are well known as high sensitive materials to detect toxic gases. And the sensitivity is improved if catalysts are added. Detecting toxic gases, especially DMMP (di-methyl-methyl-phosphonate) and DPGME (Dipropylene glycol methyl ether), was performed by a mixture of Tin oxide ($SnO_{2}$) and Zirconia ($ZrO_{2}$). The films consist of each three different mass% of Zr (from 1 mass% to 5 mass%), and they were tested by XRD, SEM, TEM, BET. Nano-structure, pore and particle size was controlled to verify the sensor's sensing mechanism. The sensors was evaluated at five different degrees (from $200^{\circ}C$ to $400^{\circ}C$) and three different concentrations (from 500 ppb to 1500 ppb). The sensors had good sensitivity of both simulants, and high selectivity of DMMP.

• 한국정보통신학회논문지
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• 제6권2호
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• pp.315-322
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• 2002

반도체 제조공정과 미세가공 기술을 이용하여 30$0^{\circ}C$의 동작온도에서 약 60㎽의 전력소모를 갖는 산화물 반도체 박막 가스센서 어레이를 제조하였다. 멤브레인의 우수한 열적 절연은 0.1$\mu\textrm{m}$ 두께의 Si$_3$N$_4$와 1$\mu\textrm{m}$ 두께의 PSG의 이중 층에 의한 것으로, 각각 LPCVD(저압화학 기상증착)와 APCVD(대기압 화학 기상증착)에 의해 제조되었다. 센서 어레이의 4가지 산화물 반도체 박막 감지물질로는 1wt.%Pd가 도핑된 SnO$_2$, 6wt.% $Al_2$O$_3$가 도핑된 ZnO, WO$_3$, ZnO를 이용하였으며, 제조된 초소형 산화물 반도체 박막 가스센서 어레이는 여러 가지 가스의 노출시 유용한 저항 변화를 나타내었고 감도는 감지 물질에 강하게 의존함을 알 수 있었다. 센서 소자의 공정 수율을 증진시키기 위하여 히터 부위를 함몰하는 공정 방법을 취하였으며, 그 결과 월등한 수율 개선을 도모할 수 있었다.