• 한국세라믹학회지
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• 제52권3호
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• pp.173-179
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• 2015

We report the facile synthesis of graphene-$CdLa_2S_4$ composite through a facile solvothermal method at low temperature. The as-prepared products were characterized by X-ray diffraction (XRD) and by Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and BET analysis, revealing the uniform covering of the graphene nanosheet with $CdLa_2S_4$ nanocrystals. The as-prepared samples show a higher efficiency for the photocatalytic degradation of typical MB dye compared with P25 and $CdLa_2S_4$ bulk nanoparticles. The enhancement of visible-light-responsive photocatalytic properties by decolorization of Rh.B dye may be attributed to the following causes. Firstly, graphene nanosheet is capable of accepting, transporting and storing electrons, and thus retarding or hindering the recombination of the electrons with the holes remaining on the excited $CdLa_2S_4$ nanoparticles. Secondly, graphene nanosheet can increase the adsorption of pollutants. The final cause is that their extended light absorption range. This work not only offers a simple way to synthesize graphene-based composites via a one-step process at low temperature but also a path to obtain efficient functional materials for environmental purification and other applications.

• 한국재료학회지
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• 제22권10호
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• pp.504-507
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• 2012

Synthesis of RGO (reduced graphene oxide)-CdS composite material was performed through CBD (chemical bath deposition) method in which graphene oxide served as the support and Cadmium Sulfate Hydrate as the starting material. Graphene-based semiconductor photocatalysts have attracted extensive attention due to their usefulness for environmental and energy applications. The band gap (2.4 eV) of CdS corresponds well with the spectrum of sunlight because the crystalline phase, size, morphology, specic surface area and defects, etc., of CdS can affect its photocatalytic activity. The specific surface structure (morphology) of the photocatalyst can be effective for the suppression of recombination between photogenerated electrons and holes. Graphene (GN) has unique properties such as a high value of Young's modulus, large theoretical specific surface area, excellent thermal conductivity, high mobility of charge carriers, and good optical transmittance. These excellent properties make GN an ideal building block in nanocomposites. It can act as an excellent electron-acceptor/transport material. Therefore, the morphology, structural characterization and crystal structure were observed using various analytical tools, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. From this analysis, it is shown that CdS particles were well dispersed uniformly in the RGO sheet. Furthermore, the photocatalytic property of the resulting RGO-CdS composite is also discussed in relation to environmental applications such as the photocatalytic degradation of pollutants. It was found that the prepared RGO-CdS nanocomposites exhibited enhanced photocatalytic activity as compared with that of CdS nanoparticles. Therefore, better efficiency of photodegradation was found for water purification applications using RGO-CdS composite.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.627-627
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• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.51-58
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• 2023

The effective detection of human chorionic gonadotropin (HCG) is considerably important for the clinical diagnosis of both of early pregnancy and nonpregnancy-related diseases. In this work, a simple and sensitive electrochemical sandwich-type immunosensing platform was designed by synthesizing b-cyclodextrin (CD) functionalized graphene (CD/GN) hybrid as simultaneously sensing platform and signal transducer coupled with rhodamine b (RhB) as probe. In brief, GN offers large surface area and high conductivity, while CD exhibits superior host-guest recognition capability, thus the primary antibody (Ab1) of HCG can be bound into the cavities of CD/GN to form stable Ab1/CD/GN inclusion complex; meanwhile, the secondary antibody (Ab2) and RhB can also enter into the cavities, producing RhB/Ab2/CD/GN complex. Then, by using Ab1/CD/GN as sensing platform and RhB/Ab2/CD/GN as signal transducer (in which RhB was signal probe), a simple sandwich-type immunosensor was constructed. Under the optimum parameters, the designed immunosensor exhibited a considerable low analytical detection of 1.0 pg mL^-1 and a wide linearity of 0.002 to 10.0 ng mL^-1 for HCG, revealing the developed sandwich-type electrochemical immunosensing platform offered potential real applications for the determination of HCG.

• 공업화학
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• 제31권1호
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• pp.25-29
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• 2020

본 연구에서는 롤 공정으로 제작된 고분자(polydimethylsiloxane, PDMS)/그래핀(graphene) 복합재료를 기판으로 하여 간단한 표면처리 공정을 통해 센서를 구현하였고, 이 센서의 성능과 거동에 대한 고찰을 실시하였다. 고분자와 그래핀 파우더를 혼합한 전구체를 3-롤 공정으로 제조하였고, 이를 2-롤 공정에 도입하여 고분자/그래핀 기판 소재를 제조하였다. 나아가, 간단한 표면처리 공정을 통하여 센서의 요체가 되는 환형 다당류(cyclodextrin, CD)를 도입하였다. 표면처리의 유효성의 적외선 분광기를 통해서 확인하였고, 전기 신호 전달의 가능성을 옴의 법칙을 통하여 분석하였다. 간단한 형태의 센서를 구현하여, 분석 물질(methyl paraben, MePRB)을 도입하였을 때, 아주 낮은 농도 수준(10 nM)까지 감지 신호를 얻을 수 있었다. 특히, 그래핀의 함량이 낮을 경우 센서 측정이 어려움을 확인할 수 있었다. 이는, 높은 그래핀 함량에서 보여주는 그래핀 입자의 배향이 다소 억제되어 발생하였을 것으로 사료된다. 이는 첨가제의 물리적인 배향이 센서의 성능에 영향을 미칠 수 있다는 것을 의미한다. 이 정보는 향후 유사한 시스템의 센서를 구현하는 연구에 도움이 될 것으로 기대된다.