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Copper zinc tin sulfide solar cells were fabricated by using spray pyrolysis from a window layer to an absorber layer. ZnS and In2S3 buffer layers were deposited on the TiO2 layer, and the photovoltaic characteristics were investigated. The ZnS buffer demonstrated a poor photovoltaic performance because of its poor surface coverage and micro-cracks at fluorine-doped tin oxide/TiO2 layers. The In2S3 buffer layer sprayed at low temperature (<360 °C) showed a large difference between photo and dark currents beyond the open-circuit voltage (VOC). When the spraying temperature exceeded 390 °C, the devices showed high dark leakage currents at reverse biases because of the high conductivity of the buffer layer, resulting in decreased VOC and short-circuit current density (JSC). The optimum temperature for spraying In2S3 is 360 °C, and the best performing device showed 410 mV, 30.4 mA/cm2, 35.3%, and 4.4% of VOC, JSC, fill factor, and efficiency, respectively.
Dongho Lee; JungYup Yang. Investigation of Cu2ZnSnS4 solar cell buffer layer fabricated via spray pyrolysis. Current Applied Physics 2020, 21, 184 -191.
AMA StyleDongho Lee, JungYup Yang. Investigation of Cu2ZnSnS4 solar cell buffer layer fabricated via spray pyrolysis. Current Applied Physics. 2020; 21 ():184-191.
Chicago/Turabian StyleDongho Lee; JungYup Yang. 2020. "Investigation of Cu2ZnSnS4 solar cell buffer layer fabricated via spray pyrolysis." Current Applied Physics 21, no. : 184-191.
Three-dimensional stackable memory frames involving the integration of two-terminal scalable crossbar arrays are expected to meet the demand for high-density memory storage, fast switching speed, and ultra-low power operation. However, two-terminal crossbar arrays introduce an unintended sneak path, which inevitably requires bidirectional nonlinear selectors. In this study, the advanced threshold switching (TS) features of ZnTe chalcogenide material-based selectors provide bidirectional threshold switching behavior, nonlinearity of 104, switching speed of less than 100 ns, and switching endurance of more than 107. In addition, thermally robust ZnTe selectors (up to 400 ℃) can be obtained through the use of nitrogen-annealing treatment. This process can prevent possible phase separation phenomena observed in generic chalcogenide materials during thermal annealing which occurs even at a low temperature of 250 ℃. The possible characteristics of the electrically and thermally advanced TS nature are described by diverse structural and electrical analyses through the Poole–Frankel conduction model.
Gabriel Jang; Mihyun Park; Da Seul Hyeon; Woojong Kim; JungYup Yang; Jinpyo Hong. Bidirectional-nonlinear threshold switching behaviors and thermally robust stability of ZnTe selectors by nitrogen annealing. Scientific Reports 2020, 10, 1 .
AMA StyleGabriel Jang, Mihyun Park, Da Seul Hyeon, Woojong Kim, JungYup Yang, Jinpyo Hong. Bidirectional-nonlinear threshold switching behaviors and thermally robust stability of ZnTe selectors by nitrogen annealing. Scientific Reports. 2020; 10 (1):1.
Chicago/Turabian StyleGabriel Jang; Mihyun Park; Da Seul Hyeon; Woojong Kim; JungYup Yang; Jinpyo Hong. 2020. "Bidirectional-nonlinear threshold switching behaviors and thermally robust stability of ZnTe selectors by nitrogen annealing." Scientific Reports 10, no. 1: 1.
Copper Zinc Tin Sulfide (C2ZTS4) solar cells have become a fascinating research topic due to several advantages of the C2ZTS4 absorber layer, such as having non-toxic and abundantly available components. Superstrate structured C2ZTS4 solar cells were fabricated on the top of a fluorine-doped tin oxide (FTO) substrate with a spray pyrolysis method from the window layer to the absorber layer. Titanium dioxide (TiO2) and indium sulfide (In2S3) were used as the window and buffer layer, respectively. The source materials for the C2ZTS4 and buffer layers were all aqueous-based solutions. The metallic component ratio, Cu/(Zn + Sn), and the sulfur concentration in the solutions were systematically investigated. The optimum ratio of Cu/(Zn + Sn) in the film is about 0.785, while 0.18 M thiourea in the solution is the best condition for high performance. The C2ZTS4 layers deposited at lower temperatures (
Dongho Lee; JungYup Yang. Superstrate Structured FTO/TiO2/In2S3/Cu2ZnSnS4 Solar Cells Fabricated by a Spray Method with Aqueous Solutions. Coatings 2020, 10, 548 .
AMA StyleDongho Lee, JungYup Yang. Superstrate Structured FTO/TiO2/In2S3/Cu2ZnSnS4 Solar Cells Fabricated by a Spray Method with Aqueous Solutions. Coatings. 2020; 10 (6):548.
Chicago/Turabian StyleDongho Lee; JungYup Yang. 2020. "Superstrate Structured FTO/TiO2/In2S3/Cu2ZnSnS4 Solar Cells Fabricated by a Spray Method with Aqueous Solutions." Coatings 10, no. 6: 548.
CdS/CdSe quantum dot sensitized solar cells (QDSSC) fabricated by successive ionic layer adsorption and reaction (SILAR) processes was investigated, and a rate-equation model for the trapinduced power conversion efficiency (PCE) limit was developed and used to explain the experimental results. The cascade structure with a CdS:CdSe (7:7) cycle ratio showed the highest PCE of 2.55%. However, excess cycles of CdSe beyond the optimum condition decrease the device performance. The current loss when exceeding the maximum PCE condition is attributed to the trap-induced charge field that impedes the carrier extraction from the absorber layer to the titanium dioxide (TiO2) and increases recombination due to dislocation generation when the critical thickness for pseudomorphic growth is exceeded. The simulation results show that the increase in the number of dislocations beyond the critical thickness increases the recombination rate and impedes charge transfer at the interface between TiO2 and the QDs.
Dongho Lee; Wonjoon Choi; JungYup Yang. Investigation of the Trap-Induced Power Conversion Limit for CdS/CdSe Cascade Quantum Dot Sensitized Solar Cells Fabricated by Using the Successive Ionic Layer Adsorption and Reaction Process. Journal of the Korean Physical Society 2020, 76, 1133 -1143.
AMA StyleDongho Lee, Wonjoon Choi, JungYup Yang. Investigation of the Trap-Induced Power Conversion Limit for CdS/CdSe Cascade Quantum Dot Sensitized Solar Cells Fabricated by Using the Successive Ionic Layer Adsorption and Reaction Process. Journal of the Korean Physical Society. 2020; 76 (12):1133-1143.
Chicago/Turabian StyleDongho Lee; Wonjoon Choi; JungYup Yang. 2020. "Investigation of the Trap-Induced Power Conversion Limit for CdS/CdSe Cascade Quantum Dot Sensitized Solar Cells Fabricated by Using the Successive Ionic Layer Adsorption and Reaction Process." Journal of the Korean Physical Society 76, no. 12: 1133-1143.
Cu(In,Ga)Se2 (CIGSe) has been proven to be a better candidate as a light absorber layer in thin-film solar cells. However, most processes require high vacuum and high temperature during deposition, which results in significant loss of materials and is not applicable to a flexible substrate. Solution processes often involve low processing temperature and cheap precursor, can be used with flexible substrates, and offer the possibility of roll-to-roll manufacturing, potentially reducing manufacturing costs for the module. Here, we have experimentally investigated the optimum synthesis conditions for CIGSe nanoparticles fabricated by using a facile and a non-vacuum reflux method for low-temperature solution processes. By employing various reflux conditions by changing the temperature of heating mantle, single-phase CIGSe nanoparticles were synthesized at 200 °C. On the other hand, synthesized products with an impure multi-phase were formed at heating mantle temperatures lower than 200°C. XRD measurements confirmed that the Ga content of the CIGSe nanoparticles increased with increasing heating mantle temperature. In addition, the average diameter of the CIGSe nanoparticles increased with increasing reaction time from 5 min to 30 min at a fixed heating mantle temperature of a 200 °C. The optical band gap is calculated by using ultraviolet-visible (UV-Vis) absorption spectra, decreased from 1.69 eV to 1.29 eV with increasing reaction time due to the increased CIGSe nanoparticles size. From our results, we can conclude that the characteristics of the CIGSe nanoparticles can be effectively controlled by using simple growth conditions, thereby providing many advantages for the fabrication of absorber layers for use in CIGSe solar cells.
Mijoung Kim; Yongjei Lee; JungYup Yang; Minjae Lee; Yoonmook Kang; Pilho Huh. Investigation of Optimum Conditions for Synthesis of Cu(In,Ga)Se2 Nanoparticles by Refluxing. Journal of the Korean Physical Society 2020, 76, 527 -532.
AMA StyleMijoung Kim, Yongjei Lee, JungYup Yang, Minjae Lee, Yoonmook Kang, Pilho Huh. Investigation of Optimum Conditions for Synthesis of Cu(In,Ga)Se2 Nanoparticles by Refluxing. Journal of the Korean Physical Society. 2020; 76 (6):527-532.
Chicago/Turabian StyleMijoung Kim; Yongjei Lee; JungYup Yang; Minjae Lee; Yoonmook Kang; Pilho Huh. 2020. "Investigation of Optimum Conditions for Synthesis of Cu(In,Ga)Se2 Nanoparticles by Refluxing." Journal of the Korean Physical Society 76, no. 6: 527-532.
Organic–inorganic halide perovskite solar cells (PSCs) have excellent chemical, electronic, and optical properties, making them attractive next-generation thin-film solar cells. Typical PSCs were fabricated with a perovskite absorber layer between the TiO2 electron-transport layer (ETL) and the 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene (Spiro-OMeTAD) hole-transport layer (HTL). We examined the influence of phenyl-C61-butyric acid methyl ester (PCBM) on the PSC device. PSCs using the PCBM layer as an ETL were investigated, and the absorber layer was coated by dissolving PCBM in a methyl ammonium lead iodide (MAPbI3) precursor solution to examine the changes at the perovskite interface and inside the perovskite absorber layer. The PSCs fabricated by adding a small amount of PCBM to the MAPbI3 solution exhibited a significantly higher maximum efficiency of 16.55% than conventional PSCs (14.34%). Fabricating the PCBM ETL and PCBM-MAPbI3 hybrid solid is expected to be an efficient route for improving the photovoltaic performance.
Mijoung Kim; MoonHoe Kim; Jungseock Oh; Namhee Kwon; Yoonmook Kang; JungYup Yang. Phenyl-C61-Butyric Acid Methyl Ester Hybrid Solution for Efficient CH3NH3PbI3 Perovskite Solar Cells. Sustainability 2019, 11, 3867 .
AMA StyleMijoung Kim, MoonHoe Kim, Jungseock Oh, Namhee Kwon, Yoonmook Kang, JungYup Yang. Phenyl-C61-Butyric Acid Methyl Ester Hybrid Solution for Efficient CH3NH3PbI3 Perovskite Solar Cells. Sustainability. 2019; 11 (14):3867.
Chicago/Turabian StyleMijoung Kim; MoonHoe Kim; Jungseock Oh; Namhee Kwon; Yoonmook Kang; JungYup Yang. 2019. "Phenyl-C61-Butyric Acid Methyl Ester Hybrid Solution for Efficient CH3NH3PbI3 Perovskite Solar Cells." Sustainability 11, no. 14: 3867.
The sunshade method for the measurement of the ideality factor and resistances of solar cells is commonly used in silicon solar cells. However, the method is rarely employed for thin-film solar cells. In this paper, the sunshade method is applied to CIGS solar cells, and it is shown that the three major assumptions of the method remain valid for CIGS solar cells. The extracted parameters are compared to those calculated using other common methods, and the ideality factors and Rs values are quickly determined and found to be nearly the same as those extracted through illuminated I–V fitting and dark I–V fitting.
Sungeun Park; Soo Min Kim; Se Jin Park; Soohyun Bae; Hyomin Park; Jung Gyu Nam; Dongho Lee; Jung Yup Yang; Dong Seop Kim; Chanbin Mo; Young-Su Kim; Jihyun Kim; Hae-Seok Lee; Yoonmook Kang. Rapid and Accurate Measurement of Ideality Factor and Parasitic Resistances of Thin Film Solar Cells. ECS Journal of Solid State Science and Technology 2018, 7, Q105 -Q108.
AMA StyleSungeun Park, Soo Min Kim, Se Jin Park, Soohyun Bae, Hyomin Park, Jung Gyu Nam, Dongho Lee, Jung Yup Yang, Dong Seop Kim, Chanbin Mo, Young-Su Kim, Jihyun Kim, Hae-Seok Lee, Yoonmook Kang. Rapid and Accurate Measurement of Ideality Factor and Parasitic Resistances of Thin Film Solar Cells. ECS Journal of Solid State Science and Technology. 2018; 7 (6):Q105-Q108.
Chicago/Turabian StyleSungeun Park; Soo Min Kim; Se Jin Park; Soohyun Bae; Hyomin Park; Jung Gyu Nam; Dongho Lee; Jung Yup Yang; Dong Seop Kim; Chanbin Mo; Young-Su Kim; Jihyun Kim; Hae-Seok Lee; Yoonmook Kang. 2018. "Rapid and Accurate Measurement of Ideality Factor and Parasitic Resistances of Thin Film Solar Cells." ECS Journal of Solid State Science and Technology 7, no. 6: Q105-Q108.
The back-contact crystalline solar cell features a design in which the positive emitter and negative back surface field are both located on the rear surface. The obvious benefit of this design is that efficiency can be improved by eliminating shading from the front metal grid. However, fabricating devices with the conventional back contact configuration requires costly patterning. The high manufacturing costs and complexity of the patterning process has been a barrier in preventing the solar cell industry from adopting the back-contact design despite it having the highest conversion efficiency. To reduce costs and the number of processes, we fabricated interdigitated back-contact solar cells using an ion implantation process with a shadow mask instead of the conventional patterning and diffusion process, and achieved a 22.9% conversion efficiency. To analyze the cost-performance of ion implantation process, we developed a bottom-up cost model involving five categories: depreciation expenses, materials, labor, utility, and maintenance costs assuming a production of 300 MW/year. The reduction in process steps using ion implantation substantially decreased the initial capital expenses. This impacted the overall cost structure and reduced the cell processing costs by 20% compared to conventional back-contact solar cells.
Jungho Song; Chanbin Mo; Dongseop Kim; Junggyu Nam; Jung Yup Yang; Dongchul Suh; Hyomin Park; Soohyun Bae; Se Jin Park; Sungeun Park; Hae-Seok Lee; Young-Su Kim; Yoonmook Kang; Donghwan Kim. Cost-Performance Analysis for Interdigitated Back-Contact Solar Cells Using Ion Implantation Process. Nanoscience and Nanotechnology Letters 2018, 10, 548 -553.
AMA StyleJungho Song, Chanbin Mo, Dongseop Kim, Junggyu Nam, Jung Yup Yang, Dongchul Suh, Hyomin Park, Soohyun Bae, Se Jin Park, Sungeun Park, Hae-Seok Lee, Young-Su Kim, Yoonmook Kang, Donghwan Kim. Cost-Performance Analysis for Interdigitated Back-Contact Solar Cells Using Ion Implantation Process. Nanoscience and Nanotechnology Letters. 2018; 10 (4):548-553.
Chicago/Turabian StyleJungho Song; Chanbin Mo; Dongseop Kim; Junggyu Nam; Jung Yup Yang; Dongchul Suh; Hyomin Park; Soohyun Bae; Se Jin Park; Sungeun Park; Hae-Seok Lee; Young-Su Kim; Yoonmook Kang; Donghwan Kim. 2018. "Cost-Performance Analysis for Interdigitated Back-Contact Solar Cells Using Ion Implantation Process." Nanoscience and Nanotechnology Letters 10, no. 4: 548-553.
A ladder-type poly(3,4-ethylenedioxythiophene)–poly(ethylene glycol)–polyurethane (PEDOT–PEG–PU) supramolecular network was successfully synthesized using graft copolymerization of hydroxymethyl-EDOT with isocyanate-terminated PEG–PU prepolymer. PEDOT functionalized as the frame for a ladder-type supramolecular structure and PEG–PU as the rung. The successful formation of supramolecular network was confirmed by analyzing the Fourier transform infrared spectroscopy. A series of PEDOT–PEG–PU gel polymer electrolytes by linking the LiClO4 were prepared as a function of [O/Li+] ratios. The pH effect of their electrical capacitances was investigated using cyclic voltammetry. Ionic conductivities of different PEDOT–PEG–PU/Li+ complexes at a fixed pH were also evaluated through impedance analysis.
Chanhyuk Jee; Kyung Seok Kang; Hyo Jin Jung; Ji Hong Bae; Jung Yup Yang; Pil Ho Huh; H. Park. Ladder-Type Poly(3,4-ethylenedioxythiophene)–Poly(ethylene glycol)–Polyurethane Supramolecular Network for Gel Polymer Electrolyte. Polymer-Plastics Technology and Engineering 2018, 57, 1518 -1523.
AMA StyleChanhyuk Jee, Kyung Seok Kang, Hyo Jin Jung, Ji Hong Bae, Jung Yup Yang, Pil Ho Huh, H. Park. Ladder-Type Poly(3,4-ethylenedioxythiophene)–Poly(ethylene glycol)–Polyurethane Supramolecular Network for Gel Polymer Electrolyte. Polymer-Plastics Technology and Engineering. 2018; 57 (15):1518-1523.
Chicago/Turabian StyleChanhyuk Jee; Kyung Seok Kang; Hyo Jin Jung; Ji Hong Bae; Jung Yup Yang; Pil Ho Huh; H. Park. 2018. "Ladder-Type Poly(3,4-ethylenedioxythiophene)–Poly(ethylene glycol)–Polyurethane Supramolecular Network for Gel Polymer Electrolyte." Polymer-Plastics Technology and Engineering 57, no. 15: 1518-1523.
We achieve large-area (1602 × 902 mm2) doping uniformity without layer peel-offs, based on a dual Na source, ie, partial Na out-diffusion from soda-lime glass and a homogeneously sputtered CuGa:NaF layer as an auxiliary source. We systematically investigate the optoelectronic, microstructural, and compositional characteristics of Cu(In,Ga)(Se,S)2 solar cells and analyze the underlying mechanism in detail. Na out-diffusion from soda-lime glass initially improves the cell performance according to the defect passivation and Na doping effects; further Na incorporation using the Na-doped layer enhances JSC, FF, and film conductivity, which is likely due to the enhanced cell homogeneity and the alleviation of carrier transport-limited characteristics. Excessive Na incorporation triggers the possible generation of layer peel-offs, which is closely related to the reduced adhesion force, void generation, decrease in S/(S + Se) ratio, Ga redistribution, bandgap reduction, and increase in the low-energy photoluminescence. These results indicate that the voids are created via Kirkendal mechanism based on the variability in atomic diffusion rates following compositional changes, resulting from the insufficiency in Na consumption or sulfurization. It is noted that an in-line codeposition technique enables realization of high-level Na doping as well as void-free interface state by suppressing the defect generation, which yields high-efficiency commercial-scale Cu(In,Ga)(Se,S)2 modules without layer peel-off problems.
Ji Hun Park; Seunghwan Lee; Eunho Song; Sangho Shin; Changho Kang; Hyungseok Yoon; Seunghun Lee; JungYup Yang; Dongho Lee; Dongseop Kim; Junggyu Nam. Homogeneous Na incorporation for industrial-scale application of Cu(In,Ga)(Se,S)2solar cells. Progress in Photovoltaics: Research and Applications 2017, 26, 112 -126.
AMA StyleJi Hun Park, Seunghwan Lee, Eunho Song, Sangho Shin, Changho Kang, Hyungseok Yoon, Seunghun Lee, JungYup Yang, Dongho Lee, Dongseop Kim, Junggyu Nam. Homogeneous Na incorporation for industrial-scale application of Cu(In,Ga)(Se,S)2solar cells. Progress in Photovoltaics: Research and Applications. 2017; 26 (2):112-126.
Chicago/Turabian StyleJi Hun Park; Seunghwan Lee; Eunho Song; Sangho Shin; Changho Kang; Hyungseok Yoon; Seunghun Lee; JungYup Yang; Dongho Lee; Dongseop Kim; Junggyu Nam. 2017. "Homogeneous Na incorporation for industrial-scale application of Cu(In,Ga)(Se,S)2solar cells." Progress in Photovoltaics: Research and Applications 26, no. 2: 112-126.
A ladder-type poly(3,4-ethylenedioxythiophene)-poly (ethylene glycol)-polyurethane (PEDOT-PEG-PU) supramolecular network was successfully synthesized using graft copolymerization of hydroxymethyl-EDOT with isocyanate-terminated PEG-PU prepolymer. PEDOT functionalized as the frame for a ladder-type supramolecular structure and PEG-PU as the rung. The successful formation of supramolecular network was confirmed by analyzing the Fourier transform infrared spectroscopy (FTIR). A series of PEDOT-PEG-PU gel polymer electrolyte by linking the LiClO4 were prepared as a function of [O/Li+] ratios. The pH effect of their electrical capacitances was investigated using cyclic voltammetry. Ionic conductivities of different PEDOT-PEG-PU/Li+ complexes at a fixed pH were also evaluated through impedance analysis.
C. H. Jee; K. S. Kang; J. H. Bae; H. J. Jung; H. Park; Jung Yup Yang; Pilho Huh. Ladder-Type Poly(3,4-ethylenedioxythiophene)-Poly (ethylene glycol)-Polyurethane Supramolecular Network for Gel Polymer Electrolyte. Polymer-Plastics Technology and Engineering 2017, 57, 1236 -1241.
AMA StyleC. H. Jee, K. S. Kang, J. H. Bae, H. J. Jung, H. Park, Jung Yup Yang, Pilho Huh. Ladder-Type Poly(3,4-ethylenedioxythiophene)-Poly (ethylene glycol)-Polyurethane Supramolecular Network for Gel Polymer Electrolyte. Polymer-Plastics Technology and Engineering. 2017; 57 (12):1236-1241.
Chicago/Turabian StyleC. H. Jee; K. S. Kang; J. H. Bae; H. J. Jung; H. Park; Jung Yup Yang; Pilho Huh. 2017. "Ladder-Type Poly(3,4-ethylenedioxythiophene)-Poly (ethylene glycol)-Polyurethane Supramolecular Network for Gel Polymer Electrolyte." Polymer-Plastics Technology and Engineering 57, no. 12: 1236-1241.
Semi‐crystalline polypyrrole:polystyrene sulfonate (PPy:PSS) composites were synthesized successfully after passing through the micro‐pores of filter paper. Filter paper was used as a tunnel to channel the diffusion speed of the initiator and to separate the PSS chains as a function of the occupied pore volume. Fourier transform infrared spectroscopy (FT‐IR) suggested the specific bonding structures of the formed PPy:PSS. The crystallographic structures of the PPy:PSS composites were analyzed by X‐ray diffraction based on various pore sizes of the filter paper used. The crystallinity dependence of the conductivity was evaluated using a standard four‐point probe. A series of PPy:PSS samples with different crystallinity exhibited electrical conductivity ranging from 0.007 S/cm to 0.062 S/cm. POLYM. ENG. SCI., 58:1033–1036, 2018. © 2017 Society of Plastics Engineers
Kyung Seok Kang; Chanhyuk Jee; Ji-Hong Bae; Eunyoung Kim; Hyo Jin Jung; Jung Yup Yang; Pilho Huh. Semi‐crystalline polypyrrole: Polystyrene sulfonate synthesized through the pores of filter paper. Polymer Engineering & Science 2017, 58, 1033 -1036.
AMA StyleKyung Seok Kang, Chanhyuk Jee, Ji-Hong Bae, Eunyoung Kim, Hyo Jin Jung, Jung Yup Yang, Pilho Huh. Semi‐crystalline polypyrrole: Polystyrene sulfonate synthesized through the pores of filter paper. Polymer Engineering & Science. 2017; 58 (7):1033-1036.
Chicago/Turabian StyleKyung Seok Kang; Chanhyuk Jee; Ji-Hong Bae; Eunyoung Kim; Hyo Jin Jung; Jung Yup Yang; Pilho Huh. 2017. "Semi‐crystalline polypyrrole: Polystyrene sulfonate synthesized through the pores of filter paper." Polymer Engineering & Science 58, no. 7: 1033-1036.
Sulfur is extensively used to increase the bandgap of Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells and to improve the open circuit voltage (VOC) in order to optimize the characteristics of the devices. This study uses a sulfurization process to obtain a double-graded bandgap profile. Selenization was carried out on Cu(In,Ga) precursors, followed by one sulfurization process or two consecutive sulfurization processes on top of the CIGSe absorber layer surface. The optimum two-step sulfurization process provides an increase of VOC of 0.05 V and an improvement of conversion efficiency of 1.17%. The efficiency of the 30 × 30 cm2 monolithic module, which has 64 CIGS cells connected in series (aperture area: 878.6 cm2), is 15.85%. The optical and electrical properties of the phase and the work function distribution were investigated using the depth profiles of the absorber layer as a function of the sulfurization conditions. The CIGSSe thin film formed by two-step sulfurization with a high sulfur concentration exhibits a single work function peak, better crystallinity, and higher conversion efficiency than those of the thin film formed by two-step sulfurization at low sulfur concentration. In terms of the Raman spectra depth profile, the phase areas for the CIGSSe thin film that underwent the optimized high sulfur concentration two-step-sulfurization appeared to have less of Cu2-xSe phase than that with low sulfur concentration. Consequently, surface and interface phase analysis is an essential consideration to improve cell efficiency. Copyright © 2016 John Wiley & Sons, Ltd.
Gee Yeong Kim; Trang Thi Thu Nguyen; Seokhyun Yoon; Junggyu Nam; Dongho Lee; Dongseop Kim; Minsu Kwon; Chan-Wook Jeon; Yoon-Koo Kim; Seung-Yong Lee; Miyoung Kim; William Jo; Jung Yup Yang. High photo-conversion efficiency in double-graded Cu(In,Ga)(S,Se)2thin film solar cells with two-step sulfurization post-treatment. Progress in Photovoltaics: Research and Applications 2016, 25, 139 -148.
AMA StyleGee Yeong Kim, Trang Thi Thu Nguyen, Seokhyun Yoon, Junggyu Nam, Dongho Lee, Dongseop Kim, Minsu Kwon, Chan-Wook Jeon, Yoon-Koo Kim, Seung-Yong Lee, Miyoung Kim, William Jo, Jung Yup Yang. High photo-conversion efficiency in double-graded Cu(In,Ga)(S,Se)2thin film solar cells with two-step sulfurization post-treatment. Progress in Photovoltaics: Research and Applications. 2016; 25 (2):139-148.
Chicago/Turabian StyleGee Yeong Kim; Trang Thi Thu Nguyen; Seokhyun Yoon; Junggyu Nam; Dongho Lee; Dongseop Kim; Minsu Kwon; Chan-Wook Jeon; Yoon-Koo Kim; Seung-Yong Lee; Miyoung Kim; William Jo; Jung Yup Yang. 2016. "High photo-conversion efficiency in double-graded Cu(In,Ga)(S,Se)2thin film solar cells with two-step sulfurization post-treatment." Progress in Photovoltaics: Research and Applications 25, no. 2: 139-148.
We investigated the surface properties of a Mo back contact for large-area thin-film solar modules with high efficiency and good adhesion between Mo and the absorber layer. It was determined that the appropriate surface properties of Mo would improve the efficiency from 10% to above 15.0±0.21% and narrow the efficiency distribution in large-area modules. The Mo back contact was annealed at various temperatures between room temperature and 230 °C in air to control the amount of sodium diffusing from the soda-lime glass substrate during selenization and sulfurization, and to improve the uniformity of the unit cell. Before the heat treatment, the amount of sodium in the patterned area of the unit cell was more than 10 times of that in the central area of the cell. The patterned region with higher Na content had smaller grains than those in the central area with less Na, resulting in many peel-offs and shunting paths. The difference in sodium content was reduced after heat treatment. The optimized surface oxide of the Mo back contact had a thickness of around 3–5 nm and consisted of the MoO3 phase. The grain boundary of Mo columnar structure near the surface consisted of the oxide layer.
Junggyu Nam; Yoonmook Kang; Dongseop Kim; Dohyun Baek; Dongho Lee; JungYup Yang. The oxidation effect of a Mo back contact on Cu(In,Ga)(Se,S) thin-film solar modules. Solar Energy Materials and Solar Cells 2016, 144, 445 -450.
AMA StyleJunggyu Nam, Yoonmook Kang, Dongseop Kim, Dohyun Baek, Dongho Lee, JungYup Yang. The oxidation effect of a Mo back contact on Cu(In,Ga)(Se,S) thin-film solar modules. Solar Energy Materials and Solar Cells. 2016; 144 ():445-450.
Chicago/Turabian StyleJunggyu Nam; Yoonmook Kang; Dongseop Kim; Dohyun Baek; Dongho Lee; JungYup Yang. 2016. "The oxidation effect of a Mo back contact on Cu(In,Ga)(Se,S) thin-film solar modules." Solar Energy Materials and Solar Cells 144, no. : 445-450.
JungYup Yang; Junggyu Nam; Dongseop Kim; Dongho Lee; Pilho Huh. Investigation of the light soaking behaviors in two-step sputter and selenization Cu(In,Ga)(Se,S)2 solar cells with different sulfur ratios. Solar Energy Materials and Solar Cells 2016, 144, 467 -471.
AMA StyleJungYup Yang, Junggyu Nam, Dongseop Kim, Dongho Lee, Pilho Huh. Investigation of the light soaking behaviors in two-step sputter and selenization Cu(In,Ga)(Se,S)2 solar cells with different sulfur ratios. Solar Energy Materials and Solar Cells. 2016; 144 ():467-471.
Chicago/Turabian StyleJungYup Yang; Junggyu Nam; Dongseop Kim; Dongho Lee; Pilho Huh. 2016. "Investigation of the light soaking behaviors in two-step sputter and selenization Cu(In,Ga)(Se,S)2 solar cells with different sulfur ratios." Solar Energy Materials and Solar Cells 144, no. : 467-471.
Cu(In,Ga)(Se,S)2 (CIGSS) absorber layers were fabricated by using a modified two-stage sputter and a sequential selenization/sulfurization method, and the sulfurization process is changed from one-step to two-step. The two-step sulfurization was controlled with two different H2S gas concentrations during the sulfurization treatment. This two-step process yielded remarkable improvements in the efficiency (+0.7%), open circuit voltage (+14 mV), short circuit current (+0.23 mA/cm2), and fill factor (+0.21%) of a CIGSS device with 30 × 30 cm2 in size, owing to the good passivation at the grain boundary surface, uniform material composition among the grain boundaries, and modified depth profile of Ga and S. The deterioration of the P/N junction quality was prevented by the optimized S content in the CIGSS absorber layer. The effects of the passivation quality at the grain boundary surface, the material uniformity, the compositional depth profiles, the microstructure, and the electrical characteristics were examined by Kelvin probe force microscopy, X-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and current-voltage curves, respectively. The two-step sulfurization process is experimentally found to be useful for obtaining good surface conditions and, enhancing the efficiency, for the mass production of large CIGSS modules.
JungYup Yang; Junggyu Nam; Dongseop Kim; GeeYeong Kim; William Jo; Yoonmook Kang; Dongho Lee. Enhancement of the photo conversion efficiencies in Cu(In,Ga)(Se,S)2 solar cells fabricated by two-step sulfurization process. Applied Physics Letters 2015, 107, 193901 .
AMA StyleJungYup Yang, Junggyu Nam, Dongseop Kim, GeeYeong Kim, William Jo, Yoonmook Kang, Dongho Lee. Enhancement of the photo conversion efficiencies in Cu(In,Ga)(Se,S)2 solar cells fabricated by two-step sulfurization process. Applied Physics Letters. 2015; 107 (19):193901.
Chicago/Turabian StyleJungYup Yang; Junggyu Nam; Dongseop Kim; GeeYeong Kim; William Jo; Yoonmook Kang; Dongho Lee. 2015. "Enhancement of the photo conversion efficiencies in Cu(In,Ga)(Se,S)2 solar cells fabricated by two-step sulfurization process." Applied Physics Letters 107, no. 19: 193901.
We have achieved 17.9% efficiency in a 30 × 30 cm2 Cu(In,Ga)(Se,S)2 solar cell sub‐module prepared by selenization and sulfurization processes with a Cd‐free buffer. The development of an absorber layer, transparent conducting oxide window layer, and module design was the key focus. This permitted 1.8% higher efficiency than our last experimental result. The quantity and the injection time of the sodium were controlled, resulting in higher open circuit voltage (Voc) and short circuit current (Jsc). In order to increase Jsc, we changed the thickness of the window layer. Boron‐doped zinc oxide was optimized for higher transmittance without reducing the fill factor. The uniformity of each layer was improved, and patterns were optimized for each module. Therefore, Voc, Jsc, and FF could be theoretically improved on the reported results of, respectively, 20 mV, 2 mA/cm2, and 1.4%. The module's efficiency was measured at the Korea Test Laboratory to compare with the data obtained in‐house. Various analyses were performed, including secondary ion mass spectroscopy, photoluminescence, quantum efficiency, solar simulator, and UV–vis spectrometry, to measure the cell's depth profile, carrier lifetime, external quantum efficiency, module efficiency, and transmittance, respectively. Copyright © 2015 John Wiley & Sons, Ltd.
Junggyu Nam; Yoonmook Kang; Dongho Lee; JungYup Yang; Young-Su Kim; Chan B. Mo; Sungchan Park; Dongseop Kim. Achievement of 17.9% efficiency in 30 × 30 cm2 Cu(In,Ga)(Se,S)2 solar cell sub-module by sulfurization after selenization with Cd-free buffer. Progress in Photovoltaics: Research and Applications 2015, 24, 175 -182.
AMA StyleJunggyu Nam, Yoonmook Kang, Dongho Lee, JungYup Yang, Young-Su Kim, Chan B. Mo, Sungchan Park, Dongseop Kim. Achievement of 17.9% efficiency in 30 × 30 cm2 Cu(In,Ga)(Se,S)2 solar cell sub-module by sulfurization after selenization with Cd-free buffer. Progress in Photovoltaics: Research and Applications. 2015; 24 (2):175-182.
Chicago/Turabian StyleJunggyu Nam; Yoonmook Kang; Dongho Lee; JungYup Yang; Young-Su Kim; Chan B. Mo; Sungchan Park; Dongseop Kim. 2015. "Achievement of 17.9% efficiency in 30 × 30 cm2 Cu(In,Ga)(Se,S)2 solar cell sub-module by sulfurization after selenization with Cd-free buffer." Progress in Photovoltaics: Research and Applications 24, no. 2: 175-182.
Dongho Lee; Jaehan Lee; Sung Heo; Jong-Bong Park; Young-Su Kim; Chan B. Mo; Kwangsoo Huh; JungYup Yang; Junggyu Nam; Dohyun Baek; Sungchan Park; ByoungJune Kim; Dongseop Kim; Yoonmook Kang. Direct evidence of void passivation in Cu(InGa)(SSe)2 absorber layers. Applied Physics Letters 2015, 106, 083903 .
AMA StyleDongho Lee, Jaehan Lee, Sung Heo, Jong-Bong Park, Young-Su Kim, Chan B. Mo, Kwangsoo Huh, JungYup Yang, Junggyu Nam, Dohyun Baek, Sungchan Park, ByoungJune Kim, Dongseop Kim, Yoonmook Kang. Direct evidence of void passivation in Cu(InGa)(SSe)2 absorber layers. Applied Physics Letters. 2015; 106 (8):083903.
Chicago/Turabian StyleDongho Lee; Jaehan Lee; Sung Heo; Jong-Bong Park; Young-Su Kim; Chan B. Mo; Kwangsoo Huh; JungYup Yang; Junggyu Nam; Dohyun Baek; Sungchan Park; ByoungJune Kim; Dongseop Kim; Yoonmook Kang. 2015. "Direct evidence of void passivation in Cu(InGa)(SSe)2 absorber layers." Applied Physics Letters 106, no. 8: 083903.
Jung Yup Yang; Young Kyoung Ahn; Pil Ho Huh; Jung Gyu Nam; Min Park; Min Gu Kim; Jun Young Lee; Yang Geun Ji; Dong Seop Kim. Research on decrease of cell to module loss for crystalline silicon photovoltaic module. Journal of Renewable and Sustainable Energy 2013, 5, 52003 .
AMA StyleJung Yup Yang, Young Kyoung Ahn, Pil Ho Huh, Jung Gyu Nam, Min Park, Min Gu Kim, Jun Young Lee, Yang Geun Ji, Dong Seop Kim. Research on decrease of cell to module loss for crystalline silicon photovoltaic module. Journal of Renewable and Sustainable Energy. 2013; 5 (5):52003.
Chicago/Turabian StyleJung Yup Yang; Young Kyoung Ahn; Pil Ho Huh; Jung Gyu Nam; Min Park; Min Gu Kim; Jun Young Lee; Yang Geun Ji; Dong Seop Kim. 2013. "Research on decrease of cell to module loss for crystalline silicon photovoltaic module." Journal of Renewable and Sustainable Energy 5, no. 5: 52003.