• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.2
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• pp.78-81
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• 2020

Quantum dot efficiency was increased to evaluate reliability and optical characteristics using incidental materials. Quantum dot was manufactured by wrapping a sandwich type quantum layer using a product with a barrier property to prevent water and oxygen because it is vulnerable to oxygen and moisture. We used the three quantum dot films consisting of quantum dot only and quantum dot products consisting of film and barrier film combined with PET in the quantum dot product to evaluate the change over 650 hours under high temperature and high humidity conditions at 60℃ and 90 % humidity. As a result, the quantum dot product with Barrier Film has lowered luminance by 8 %, CIE x by 2 % and CIE y by 8 %. Quantum dot products exposed to moisture and oxygen were oxidized and measured low before measurement.

• Transactions of the Society of Information Storage Systems
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• v.8 no.1
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• pp.1-5
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• 2012

We present a method for preparing a quantum dot fluorescent monolayer film on a glass substrate. Since nanoparticles aggregate easily, it is difficult to prepare a nanoparticle monolayer film. We have used a covalent bond, the peptide bond, to fix quantum dots on the glass substrate. The surface of the quantum dot was functionalized with carboxyl groups, and the glass substrate was also functionalized with amino groups using a silane coupling agent. The carboxyl group can be strongly coupled to the amino group. We were able to successfully prepare a monolayer film of CdSe quantum dots on the glass substrate.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.1-6
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• 2009

To overcome the stability problem of hydrophilic quantum dot (Q-dot), cellular uptake of hydrophobic instead of hydrophilic Q-dot was studied in the hope to find a simple method to use Q-dot as a cellular imaging probe. Hydrophobic Q-dot and poly-L-lactic acid (PLLA) were co-dissolved in chloroform to prepare stable films. Due to the cellular compatibility of PLLA, adherent cells were cultured on the film to observe the degree of Q-dot uptake and cytotoxicity of the prepared films. The results show that Q-dots were absorbed into NIH3T3 and EMT6 cells. Cellular uptake was also observed when hydrophobic Q-dots were coated directly on a glass plate. PLLA/Q-dot film and Q-dot coated on glass plate did not show major cytotoxicity. In vivo tumor model was also used to show the uptake of Q-dot from the PLLA/Q-dot film to the tumor site.

• Journal of Powder Materials
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• v.19 no.6
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• pp.451-457
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• 2012

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.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.135.2-135.2
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• 2014

Photon conversion technology for thin film solar cells is reviewed. The high-energy photons which are hardly absorbed in solar cells can be transformed the low energy photon by the photon conversion process such as down conversion or down shift, which can improve the solar cell efficiency over the material limit. CdSe-based quantum dot materials commonly used in LED can be used as the photon conversion layer for Si thin film solar cells. The photon conversion structure of CdSe-based quantum dot for Si thin film solar cells will be presented and the pros and cons for the Si thin film solar cells integrated with the photon conversion layers will be discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.988-993
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• 2004

Luminescence characteristics of Ag-doped ZnO as the quantum dot materials to increasing the efficiency on dye-sensitized solar cells (DSC) have been studied. Ag doped ZnO powder was produced by the self-sustaining combustion process using ultrasonic spraying heating method. Luminescence wavelength region of the ZnO by Ag doping was shifted to longer wavelength. Tn the case of the Ag doped ZnO powder, broad luminescence spectrum centered on 600nm was observed. On the other hand, we compared PL data of RTA treated ZnO:Ag film at various temperatures because the front electrode of solar cell was in need of the sintering process. In XRD and PL data for RTA treated film at the 500$^{\circ}C$ showed good property. And, it was found that the grain size wasn't growing but only optical property was changed. According to the result of XRD, PL, absorption, emission spectrum and DV-X${\alpha}$ used in theoretical calculation, it is considered to be possible to use Ag doped ZnO as quantum dot material for improving DSC efficiency.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.167-171
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• 2014

While the development of a portable plate panel display, thinning, high color reproduction, high brightness studies have been actively performed. LED, OLED is used as a light source. The research on quantum dot is much accomplished by the material of light source. Such quantum dot is the next generation semiconductor nano fluorescent substance because quantum dot has the high color reproduction and flexible display characteristic. In this study, we presented to method of using the quantum dot for implementation of the plate panel display. Quantum Dot (CdSe/ZnS), having a 100um thickness, is spread in PET barrier film. A Blue LED having a wavelength of 455nm as a light source irradiating light to the optical characteristic of the devices produced and evaluated. Also we presented the possibility for application with the color change film of the LCD.

• Journal of the Korean Chemical Society
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• v.59 no.1
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• pp.97-102
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• 2015

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1376-1381
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• 2004

Understanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and optoelectronic devices based on quantum structures. $Chen^{(1)}$ developed ballistic diffusive equation(BDE) for alternatives of the Boltzmann equation that can be applied to the complex geometrical situation. In this study, a simulation code based on BDE is developed and applied to the 1-dimensional transient heat conduction across a thin film and transient 2-dimensional heat conduction across the film with heater. The obtained results are compared to the results of the $Chen^{(1)}$ and Yang and $Chen^{(1)}$. Finally, steady 2-dimensional heat conduction in the quantum dot superlattice are solved to obtain the equivalent thermal conductivity of the lattice and also compared with the experimental data from $Borca-Tasciuc^{(2)}$.

• Journal of the Korean Solar Energy Society
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• v.39 no.1
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• pp.1-9
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• 2019

Light induced degradation is one of the major research challenges of hydrogenated amorphous silicon related thin film silicon solar cells. Amorphous silicon shows creation of metastable defect states, originating from elevated concentration of dangling bonds during light exposure. The metastable defect states work as recombination centers, and mostly affects quality of intrinsic layer in solar cells. In this paper we present results of light induced degradation in thin film silicon solar cells and discussion on physical origin, mechanism and practical solutions of light induced degradation in thin film silicon solar cells. In-situ light-soaking IV measurement techniques are presented. We also present thin film silicon material with silicon nano-quantum dots embedded within amorphous matrix, which shows superior stability during light-soaking. Our results suggest that solar cell using silicon nano-quantum dots in abosrber layer shows superior stability under light soaking, compared to the conventional amorphous silicon solar cell.