• 센서학회지
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• 제26권5호
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• pp.366-369
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• 2017

This work presents a detailed study of several parameters on the spray coating method for fabricating a flexible cantilever. Conventionally, spin coating method have been widely used in the microelectromechanical system (MEMS) fabrication process. However, the major drawback of this method is the difficulties in protecting various topography with photoresist film, particularly when the device is manufactured in high aspect ratio. It is also a challenging process to form a small pattern in the etched area. On the other hand, the commercial spray coating systems are not advantageous from an economic perspective and the technique is also providing less efficient. In order to solve these issues, we have developed a manual spray coating system which can be efficiently used by combining the accessories available in the laboratory. The developed spray coating system consists of a spin-coater, motorized stage, a spray gun with the capable of controlling centrifugal force, injection amount, injection angle, and spray range. The major advantage of the proposed spray coating system is its reasonable fabrication cost. Secondly, the system can be easily disassembled after finishing the coating experiment. Owing to the mentioned advantages, we sincerely believe that the proposed spray coating system can be effectively used in many related applications.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.291-291
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• 2010

Organic solar cells have attracted much interest due to the potential advantage of the lightness, simple solution processing and flexibility. Until recently, the focus of organic solar cells research has been on optimization of material processing to improve the power conversion efficiency. However, area scaling is an important position for alternative to the market dominating solar cells. Spray deposition technologies have advantage of less material wastage and possibility of large scale photoactive area coating when compared with spin coating process. We investigated the performance of organic solar cells as a function of active area using two types of deposition process. The commonly used process is spin coating which can be fabricated organic materials deposition for devices. Spray deposition process compare with spin coating for large-area organic solar cells. The spray deposition organic layer shows excellent performance up to the active area of $4\;cm^2$ with the PCE of ~3.0 % under AM.1.5 simulated illumination with an intensity of $100mW/cm^2$. This indicates that the spray deposition process can be used as a mass production process for evaluating large-area organic solar cells.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.420.1-420.1
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• 2016

Colloidal quantum dot (CQD) is emerging as a promising active material for next-generation solar cell applications because of its inexpensive and solution-processable characteristics as well as unique properties such as a tunable band-gap due to the quantum-size effect and multiple exciton generation. However, the most widely used spin-coating method for the formation of the quantum dot (QD) active layers is generally hard to be adopted for high productivity and large-area process. Instead, the spray-coating technique may potentially be utilized for high-throughput production of the CQD solar cells (CQDSCs) because it can be adapted to continuous process and large-area deposition on various substrates although the cell efficiency is still lower than that of the devices fabricated with spin-coating method. In this work, we observed that the subsequent treatment of two different ligands, halide ion and butanedithiol, on the lead sulfide (PbS) QD layer significantly enhanced the cell efficiency of the spray CQDSCs. The maximum power conversion efficiency was 5.3%, comparable to that of the spin-coating CQDSCs.

• 대한기계학회논문집B
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• 제39권5호
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• pp.463-469
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• 2015

산화그래핀 소재를 합성하여 투명한 박막 코팅기술을 개발하고 특성을 평가하였다. 스핀과 스프레이 공정을 동시에 이용하여 산화그래핀을 유리 기판에 균일하게 박막코팅을 하였다. 균일하게 산화그래핀을 스핀-스프레이 공정을 이용하여 박막코팅을 하기 위하여 유리기판을 amine-functional group으로 표면개질을 하였다. 또한, 스핀-스프레이 공정을 이용하여 산화그래핀 박막을 4층까지 적층을 하였고 86% 이상의 투명도를 확보하였다. 이와 같은 합성된 산화그래핀 박막소재의 스핀-스프레이 코팅 기술은 다양한 전자제품들의 display를 대면적으로 코팅할 수 있을 것으로 기대되어진다.

• 반도체디스플레이기술학회지
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• 제13권1호
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• pp.19-25
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• 2014

This study demonstrates transparent electrodes with characteristics desirable for touch screen panels using carbon nanotubes (CNTs). This has been accomplished by depositing CNTs on glass substrates via spray coating and then depositing thin conductive polymer films on the CNTs via spin coating. For all of the samples, such as CNTs, conductive polymers, and polymer-coated CNTs, the surface morphologies, sheet resistances, visible transmittances, chromatic properties are characterized as functions of their preparation conditions, such as the spray times for CNTs and the spin speeds for conductive polymers. The experimental results confirm that only the polymer-coated CNTs can satisfy all of the requirements that are required for electrodes of touch screen panels, such as the sheet resistance lower than $100{\Omega}/sq$, the visible transmittance higher than 80 %, and the yellowness smaller than 1.

• 한국표면공학회지
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• 제54권2호
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• pp.77-83
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• 2021

In this study, we investigated various coating methods of graphene oxide on the surface of a petri dish made of polystyrene and analyzed the physical and chemical properties of the coated surface. For coating, spinning, spraying and pressing methods were attempted. The coated surface was characterized by SEM, Raman Spectroscopy, AFM, FT-IR, UV-Vis Spectroscopy and Contact Angle measurement. By spin coating and spray coating, well distributed graphene oxide in the form of multiple islands on the plastic surface with an average size of 5 to 20㎛ are observed by SEM, and high binding energy between graphene oxide and plastic surface is measured by AFM. In case of hand press coating, graphene oxide of 10㎛ or more was observed, and low surface energy was measured. By FT-IR and Raman Spectroscopy analysis, surface coating of graphene oxide was confirmed.

• 한국분말재료학회지
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• 제29권4호
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• pp.297-302
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• 2022

This study compares the characteristics of a compact TiO₂ (c-TiO₂) powdery film, which is used as the electron transport layer (ETL) of perovskite solar cells, based on the manufacturing method. Additionally, its efficiency is measured by applying it to a carbon electrode solar cell. Spin-coating and spray methods are compared, and spray-based c-TiO₂ exhibits superior optical properties. Furthermore, surface analysis by scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibits the excellent surface properties of spray-based TiO₂. The photoelectric conversion efficiency (PCE) is 14.31% when applied to planar perovskite solar cells based on metal electrodes. Finally, carbon nanotube (CNT) film electrode-based solar cells exhibits a 76% PCE compared with that of metal electrode-based solar cells, providing the possibility of commercialization.

• 한국분무공학회지
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• 제18권3호
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• pp.146-154
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• 2013

The flow of a liquid film on spin coating is investigated in the case that the fixed volume of a liquid is placed on the center of a stationary disk. Thin film equations that are well approximated when the characteristic length in the vertical direction is much smaller than that in the radial direction (${\varepsilon}{\ll}1$) and have already been proposed in the work of T.-S. Kim & M.-U. Kim (2009), are used. The differential equation that governs the free surface of a liquid when ${\varepsilon}{\ll}1$ and ${\varepsilon}Re{\ll}1$ is also derived. The basic flow is analyzed using the thin film equations and their results are compared to the results of Navier-Stokes equations.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.432-432
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• 2010

Organic light emitting diodes (OLED) thin films were fabricated by Electrostatic spray deposition (ESD). In this study, we reported the thickness, morphology, current efficiency, luminescence of OLED fabricated by ESD. These results were compared with the spin coating method, and showed that also ESD is a good fabrication method for OLED because of its characteristics similar with the results using spin coating. The active layer consists of organic blends with Poly(N-vinylcarbazole) (PVK), 2-(4-Biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), N,N'-Bis(3-methylphenyl) -N,N'-bis(phenyl)-benzidine (TPD), Tris(2-phenylpyridine)iridium(III) (Ir(ppy)3), and the structure of OLED consists of aluminum (Al), lithium fluoride (LiF), organic blends, PEDOT:PSS and Indium-tin-oxide (ITO), which was used as the top cathode, cathode interfacial layer, emitting layer and bottom anode, respectively. The results suggest that Electrostatic spray deposition is a promising method for the next generation of OLED fabrication since it has a probability fabricating large-area thin films.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.51-55
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• 2015

We have fabricated silver nanowire (AgNW) films as a stretchable and transparent electrode on polydimethylsiloxane (PDMS) substrates using a spray coater. Inherently, they show poor surface roughness and stretchability. To tackle it, we have employed a conductive polymer, poly (3,4-ethylenedioxythiophene) : Poly(styrene sulfonate) (PEDOT : PSS). PEDTO : PSS solution is mixed with AgNWs or spin-coated on the AgNW film. Compared with AgNW film only, PEDOT : PSS film only, and polymer-mixed AgNW films, the AgNW/polymer bilayer films exhibit much better surface roughness and stretchability. It is found that spray-coating of AgNWs on uncured PDMS and spin-coating of PEDOT : PSS solution on the AgNW films enhance the surface roughness of electrodes. Such a bilayer structure also provides a stable resistance under tensile strain due to the fact that each layer acts as a detour route for carriers. With this structure, we have obtained the peak-to-peak roughness ($R_{pv}$) as low as 76.8nm and a moderate increase of sheet resistance (from $10{\Omega}/{\Box}$ under 0% strain to $30{\Omega}/{\Box}$ under 40% strain).