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Moon Hee Kang

Other affiliations: Keimyung University, Air Liquide, KITECH  ...read more
Bio: Moon Hee Kang is an academic researcher from Chungbuk National University. The author has contributed to research in topics: PEDOT:PSS & Silicon. The author has an hindex of 11, co-authored 43 publications receiving 387 citations. Previous affiliations of Moon Hee Kang include Keimyung University & Air Liquide.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the levelized cost of electricity (LCOE) of a commercial scale photovoltaics (PV) system is quantitatively investigated using the System Advisor Model (SAM) from the National Renewable Energy Laboratory (NREL).

52 citations

Journal ArticleDOI
TL;DR: In this paper, the detailed optical properties of various SiN films and their effect on silicon solar cell efficiency in air and under glass is evaluated by a combination of Monte-Carlo geometrical ray tracing program, Sunrays, and a device modeling program PC1D.
Abstract: Plasma-enhanced chemical vapor deposition (PECVD) SiN films are widely used as antireflection (AR) coating for silicon solar cells and particularly for multi-crystalline solar cells for hydrogen passivation of bulk defects. In this paper, the detailed optical properties of various SiN films and their effect on silicon solar cell efficiency in air and under glass is evaluated by a combination of Monte-Carlo geometrical ray tracing program, Sunrays, and a device modeling program PC1D. Maximum module power under glass and ethylene vinyl acetate (EVA) encapsulation is used as the figure of merit for optimizing the index and thickness of the SiN films. Simulations are categorized by surface morphology (planar or textured) and ambient (air or glass). SiN films with refractive index (n) in the range of 2.03–2.42 are used for this study. It is found that although n = 2.03 is not the optimum index in terms of reflectance under glass (n = 1.5), it produces maximum cell or module efficiency under glass. This is because n = 2.03 film produces much higher cell efficiency (17.9%) in air, therefore, even after a significant optical encapsulation loss of 0.8% in absolute efficiency, the cell efficiency remains highest (17.1%) under glass. In contrast SiN film with an index of 2.4 produces only 0.5% air to glass efficiency loss but due to the low starting efficiency of 17% in air; the final cell efficiency under glass is only 16.5%. In addition, texturing provides a larger window of thickness around the optimum without affecting the optical performance. Similar analysis done for planar cells indicate that optimum index for highest module power is 2.20. This is because reflection is much higher in planar cells, therefore higher index can be tolerated before loss due to absorption in SiN exceeds the gain in reflectance under glass. Copyright © 2011 John Wiley & Sons, Ltd.

48 citations

Journal ArticleDOI
TL;DR: In this article, the fabrication of front junction n-type Si solar cells on 239 cm 2 Cz using ion implanted boron emitter and phosphorus back surface field (BSF) in combination with screen printed metallization was reported.

43 citations

Journal ArticleDOI
TL;DR: In this article, highly conductive poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) films were optimized by simple solvent post treatment and showed enhanced conductivities and reduced sheet resistances.

29 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a solid polymer source developed at SiXtron Advanced Materials to eliminate the storage and handling of dangerous pyrophoric silane gas, and used ammonia flow rate as a control for the chemical and optical properties in the silane-free process.
Abstract: We deposited plasma-enhanced chemical vapor deposition silicon carbon nitride (SiC x N y ) antireflection coating and passivation layers using a silane-free process. We used a solid polymer source developed at SiXtron Advanced Materials to eliminate the storage and handling of dangerous pyrophoric silane gas. We used ammonia flow rate as a control for the chemical and optical properties in the silane-free process. As NH 3 flow rate increases, the carbon content, refractive index, extinction coefficient, and surface charge density of the film decrease. At an ammonia flow rate of 3000 sccm, which is similar to the conventional SiN x , the extinction coefficients for the two films were similar. This led to an emitter dark saturation current density (J oe ) of 404 fA/cm 2 for the two films on 45 Ω/□ emitters. However, a stack passivation of SiO 2 /SiC x N y on an 80 Ω/□ emitter resulted in an emitter dark saturation current density of 95 fA/cm 2 , which is enough to provide a good surface passivation for high efficiency solar cells. An energy conversion efficiency of 17.4% was obtained for a 149 cm 2 textured Czochralski screen-printed solar cell with this stack passivation. For a 156 cm 2 nontextured multicrystalline silicon, with only SiC x N y and a 45 Ω/□ emitter, we obtained 14.9% efficiency.

27 citations


Cited by
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Patent
04 Jun 2015
TL;DR: In this paper, an organic light-emitting diode (OLED) display with a stretchable substrate, a thin-film transistor (TFT) formed over the substrate and including a plurality of electrodes was presented.
Abstract: An organic light-emitting diode (OLED) display is disclosed. In one aspect, the display includes a stretchable substrate, a thin film transistor (TFT) formed over the stretchable substrate and including a plurality of electrodes, an OLED electrically connected to the TFT and including a plurality of electrodes, and a plurality of interconnection lines connected to the electrodes of the OLED and the TFT. At least one of the interconnection lines is configured to move in a stretching direction and rotate an electrode selected from the electrodes of the OLED and the TFT connected to the at least one interconnection line.

453 citations

Journal ArticleDOI
TL;DR: In this paper, a new metric levelized cost of delivery (LCOD) is proposed to calculate the LCOE for the EES, which can be used to assist policymakers to consider the discount rate, the type of storage technology and sizing of components in a PV-EES hybrid system.

347 citations

Journal ArticleDOI
TL;DR: A review of the dielectric passivation coatings developed in the past two decades using a standardised methodology to characterise the metrics of surface recombination across all techniques and materials is provided in this article.
Abstract: Silicon wafer solar cells continue to be the leading photovoltaic technology, and in many places are now providing a substantial portion of electricity generation. Further adoption of this technology will require processing that minimises losses in device performance. A fundamental mechanism for efficiency loss is the recombination of photo-generated charge carriers at the unavoidable cell surfaces. Dielectric coatings have been shown to largely prevent these losses through a combination of different passivation mechanisms. This review aims to provide an overview of the dielectric passivation coatings developed in the past two decades using a standardised methodology to characterise the metrics of surface recombination across all techniques and materials. The efficacy of a large set of materials and methods has been evaluated using such metrics and a discussion on the current state and prospects for further surface passivation improvements is provided.

213 citations

Journal ArticleDOI
Jinouk Song1, Hyeonwoo Lee1, Eun Gyo Jeong1, Kyung Cheol Choi1, Seunghyup Yoo1 
TL;DR: It is indicated that EQE close to 58% and 80% can be within reach without and with additional light extraction structures, respectively, with an optimal combination of cavity engineering, low-index transport layers, and horizontal dipole orientation.
Abstract: Organic light-emitting diodes (OLEDs) are established as a mainstream light source for display applications and can now be found in a plethora of consumer electronic devices used daily. This success can be attributed to the rich luminescent properties of organic materials, but efficiency enhancement made over the last few decades has also played a significant role in making OLEDs a practically viable technology. This report summarizes the efforts made so far to improve the external quantum efficiency (EQE) of OLEDs and discusses what should further be done to push toward the ultimate efficiency that can be offered by OLEDs. The study indicates that EQE close to 58% and 80% can be within reach without and with additional light extraction structures, respectively, with an optimal combination of cavity engineering, low-index transport layers, and horizontal dipole orientation. In addition, recent endeavors to identify possible applications of OLEDs beyond displays are presented with emphasis on their potential in wearable healthcare, such as OLED-based pulse oximetry as well as phototherapeutic applications based on body-attachable flexible OLED patches. OLEDs with fabric-like form factors and washable encapsulation strategies are also introduced as technologies essential to the success of OLED-based wearable electronics.

189 citations

10 Jul 2009
TL;DR: In this paper, the relationship between the conducting filament resistance and reset voltage during the resistance switching of TiO2 thin films was examined assuming a filament with a conical shape, and it was shown that maintaining a higher set state resistance was more beneficial in achieving a more uniform reset voltage.
Abstract: This study examined the relationship between the conducting filament resistance and reset voltage during the resistance switching of TiO2 thin films assuming a filament with a conical shape. There was a critical resistance (∼20 Ω) of the set state above and below which the filament responded differently in response to the current. Maintaining a higher set state resistance was more beneficial in achieving a more uniform reset voltage. This filament model coincides well with the localized switching behavior and the recently microscopically observed filament shape.

141 citations