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We present the fabrication (using a hydrothermal process) and the properties of wearable fabrics decorated with ultrathin manganese oxide (MnO2) nanorods for supercapacitor applications. The superior mechanical durability of the supercapacitor was confirmed by cyclic voltammetry (CV) curves, which showed little change during 1000 bending cycles. The pseudocapacitive properties of the ultrathin MnO2 nanorods were confirmed by recording the CV curves at various scan rates. The galvanostatic charge–discharge curves at various specific currents confirmed the pseudocapacitance of MnO2. The ultrathin MnO2 nanorods exhibited a superior capacitance of 508 F·g−1 and an energy density of 35.3 Wh·kg−1. The MnO2 electrode with optimal properties demonstrated stable long-term cycling performance with 90% retention after 10,000 galvanostatic cycles.
Edmund Samuel; Bhavana Joshi; Yongil Kim; Chanwoo Park; Ali Aldalbahi; Mohamed El-Newehy; Hae-Seok Lee; Sam S. Yoon. Cotton fabric decorated with manganese oxide nanorods as a supercapacitive flexible electrode for wearable electronics. Applied Surface Science 2021, 568, 150968 .
AMA StyleEdmund Samuel, Bhavana Joshi, Yongil Kim, Chanwoo Park, Ali Aldalbahi, Mohamed El-Newehy, Hae-Seok Lee, Sam S. Yoon. Cotton fabric decorated with manganese oxide nanorods as a supercapacitive flexible electrode for wearable electronics. Applied Surface Science. 2021; 568 ():150968.
Chicago/Turabian StyleEdmund Samuel; Bhavana Joshi; Yongil Kim; Chanwoo Park; Ali Aldalbahi; Mohamed El-Newehy; Hae-Seok Lee; Sam S. Yoon. 2021. "Cotton fabric decorated with manganese oxide nanorods as a supercapacitive flexible electrode for wearable electronics." Applied Surface Science 568, no. : 150968.
The potential-induced degradation (PID) mechanism in Cu(In,Ga)(Se,S)2 (CIGS) thin-film solar cells, which are alternative energy sources with a high efficiency (>23%) and upscaling possibilities, remains unclear. Therefore, the cause of PID in CIGS solar cells was investigated in this study at the cell level. First, an appropriate PID experiment structure at the cell level was determined. Subsequently, PID and recovery tests were conducted to confirm the PID phenomenon. Light current–voltage (I–V), dark I–V, and external quantum efficiency (EQE) analyses were conducted to determine changes in the cell characteristics. In addition, capacitance–voltage (C–V) measurements were carried out to determine the doping concentration and width of the space charge region (SCR). Based on the results, the causes of PID and recovery of CIGS solar cells were explored, and it was found that PID occurs due to changes in the bulk doping concentration and built-in potential at the junction. Furthermore, by distinguishing the effects of temperature and voltage, it was found that PID phenomena occurred when potential difference was involved.
Solhee Lee; Soohyun Bae; Se Park; Jihye Gwak; Jaeho Yun; Yoonmook Kang; Donghwan Kim; Young-Joo Eo; Hae-Seok Lee. Characterization of Potential-Induced Degradation and Recovery in CIGS Solar Cells. Energies 2021, 14, 4628 .
AMA StyleSolhee Lee, Soohyun Bae, Se Park, Jihye Gwak, Jaeho Yun, Yoonmook Kang, Donghwan Kim, Young-Joo Eo, Hae-Seok Lee. Characterization of Potential-Induced Degradation and Recovery in CIGS Solar Cells. Energies. 2021; 14 (15):4628.
Chicago/Turabian StyleSolhee Lee; Soohyun Bae; Se Park; Jihye Gwak; Jaeho Yun; Yoonmook Kang; Donghwan Kim; Young-Joo Eo; Hae-Seok Lee. 2021. "Characterization of Potential-Induced Degradation and Recovery in CIGS Solar Cells." Energies 14, no. 15: 4628.
The electrochemical conversion of CO2 into CO using solar energy is the most efficient technique for artificial photosynthesis. However, many challenges remain, including the realisation of large-scale systems with high current density and stability. Herein, we report a carbon-supported tungsten-seed-based 3D silver dendrite ([email protected]) catalyst with abundant nanograin boundaries that exhibit enhanced CO2 reduction (CO2R) performance and stability. In zero-gap CO2 electrolyzer, [email protected] showed outstanding catalytic activity with a maximum CO partial current density of 400 mA cm–2 and stable operation for 100 h at 150 mA cm–2. The 3D dendrites improve CO2 mass transfer, while the abundant grain boundaries drive the AgxCyOz layer near the surface after activation, leading to superior CO2R catalytic activity owing to the strong local electric fields. In a stand-alone photovoltaic-electrochemical system, we achieved a solar-to-CO efficiency (ηSTC) of 12.1 % at 1 A. Thus, the synthesized catalyst and system are suitable for efficient solar energy storage.
Woong Hee Lee; Chulwan Lim; Eunseo Ban; Soohyun Bae; Jongwon Ko; Hae-Seok Lee; Byoung Koun Min; Kwan-Young Lee; Jae Su Yu; Hyung-Suk Oh. [email protected] dendrites as efficient and durable electrocatalyst for solar-to-CO conversion using scalable photovoltaic-electrochemical system. Applied Catalysis B: Environmental 2021, 297, 120427 .
AMA StyleWoong Hee Lee, Chulwan Lim, Eunseo Ban, Soohyun Bae, Jongwon Ko, Hae-Seok Lee, Byoung Koun Min, Kwan-Young Lee, Jae Su Yu, Hyung-Suk Oh. [email protected] dendrites as efficient and durable electrocatalyst for solar-to-CO conversion using scalable photovoltaic-electrochemical system. Applied Catalysis B: Environmental. 2021; 297 ():120427.
Chicago/Turabian StyleWoong Hee Lee; Chulwan Lim; Eunseo Ban; Soohyun Bae; Jongwon Ko; Hae-Seok Lee; Byoung Koun Min; Kwan-Young Lee; Jae Su Yu; Hyung-Suk Oh. 2021. "[email protected] dendrites as efficient and durable electrocatalyst for solar-to-CO conversion using scalable photovoltaic-electrochemical system." Applied Catalysis B: Environmental 297, no. : 120427.
Monolithic perovskite–silicon tandem solar cells with MoOx hole selective contact silicon bottom solar cells show a power conversion efficiency of 8%. A thin 15 nm-thick MoOx contact to n-type Si was used instead of a standard p+ emitter to collect holes and the SiOx/n+ poly-Si structure was deposited on the other side of the device for direct tunneling of electrons and this silicon bottom cell structure shows ~15% of power conversion efficiency. With this bottom carrier selective silicon cell, tin oxide, and subsequent perovskite structure were deposited to fabricate monolithic tandem solar cells. Monolithic tandem structure without ITO interlayer was also compared to confirm the role of MoOx in tandem cells and this tandem structure shows the power conversion efficiency of 3.3%. This research has confirmed that the MoOx layer simultaneously acts as a passivation layer and a hole collecting layer in this tandem structure.
Hoyoung Song; Changhyun Lee; Jiyeon Hyun; Sang-Won Lee; Dongjin Choi; DoWon Pyun; Jiyeon Nam; Seok-Hyun Jeong; Jiryang Kim; Soohyun Bae; Hyunju Lee; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee. Monolithic Perovskite-Carrier Selective Contact Silicon Tandem Solar Cells Using Molybdenum Oxide as a Hole Selective Layer. Energies 2021, 14, 3108 .
AMA StyleHoyoung Song, Changhyun Lee, Jiyeon Hyun, Sang-Won Lee, Dongjin Choi, DoWon Pyun, Jiyeon Nam, Seok-Hyun Jeong, Jiryang Kim, Soohyun Bae, Hyunju Lee, Yoonmook Kang, Donghwan Kim, Hae-Seok Lee. Monolithic Perovskite-Carrier Selective Contact Silicon Tandem Solar Cells Using Molybdenum Oxide as a Hole Selective Layer. Energies. 2021; 14 (11):3108.
Chicago/Turabian StyleHoyoung Song; Changhyun Lee; Jiyeon Hyun; Sang-Won Lee; Dongjin Choi; DoWon Pyun; Jiyeon Nam; Seok-Hyun Jeong; Jiryang Kim; Soohyun Bae; Hyunju Lee; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee. 2021. "Monolithic Perovskite-Carrier Selective Contact Silicon Tandem Solar Cells Using Molybdenum Oxide as a Hole Selective Layer." Energies 14, no. 11: 3108.
Binder-free bimetallic ZnFe2O4 nanosheets were fabricated using one-step electrodeposition, which facilitated excellent electrical contact between the ZnFe2O4 nanosheets and the nickel substrate. The resultant numerous ZnFe2O4 nanosheets with their cubic spinel structures promote interfacial activity to enhance the electrochemical and Faradaic redox reactions. The metallic Zn and Fe from the cubic spinel structure of ZnFe2O4 attract electrolytic ions and increase the energy-storage capability, thus yielding a specific capacitance of 1093 F·g −1 at a current rate of 1 A·g−1. Different samples were prepared by varying the amount of metal salts in the electrodeposition solution while maintaining a constant ZnNt:FeSO4 concentration ratio of 1:2 for all cases. The optimal electrode composition, which yielded an energy density of 54 Wh·kg−1 and a capacitance retention of 93.5% at N = 5000 charge-discharge cycles, was identified.
Bhavana Joshi; Edmund Samuel; Chanwoo Park; Yongil Kim; Hae-Seok Lee; Sam S. Yoon. Bimetallic ZnFe2O4 nanosheets prepared via electrodeposition as binder-free high-performance supercapacitor electrodes. Applied Surface Science 2021, 559, 149951 .
AMA StyleBhavana Joshi, Edmund Samuel, Chanwoo Park, Yongil Kim, Hae-Seok Lee, Sam S. Yoon. Bimetallic ZnFe2O4 nanosheets prepared via electrodeposition as binder-free high-performance supercapacitor electrodes. Applied Surface Science. 2021; 559 ():149951.
Chicago/Turabian StyleBhavana Joshi; Edmund Samuel; Chanwoo Park; Yongil Kim; Hae-Seok Lee; Sam S. Yoon. 2021. "Bimetallic ZnFe2O4 nanosheets prepared via electrodeposition as binder-free high-performance supercapacitor electrodes." Applied Surface Science 559, no. : 149951.
The electrode collects electrons produced by a solar cell. Ag crystallites generated during front electrode formation play an important role in transferring electrons from the emitter to the Ag finger. Previously, the formation mechanism of Ag crystallites and the various factors influencing Ag crystallite formation have been studied, including the effect of surface morphology on Ag crystallite formation. The glass coverage varies with the texture of the Si surface, and thus the degree of exposure of the Si surface varies correspondingly. When the Si surface is exposed, direct contact is achieved, and contact resistance is improved. However, the effect of surface morphology on the Ag crystallites formed on the Si surface under the glass layer has not yet been studied. The effect of surface morphology on Ag crystallite formation is presented in this work. Two multi-crystalline Si wafers with different surface morphologies were compared. The first multi-crystalline Si wafer was textured using metal-catalyzed chem ical etching (MCCE). The second multi-crystalline Si wafer was textured by MCCE followed by reactive ion etching. Wafers with sharper textures had lower series resistances, higher fill factors, and a large amount of Ag crystallites. Ag crystallites primarily formed at the tips of the texture. To analyze the effect of surface morphology, the surface electron concentration was confirmed by simulation. Electron concentration at the tip was proportional to the sharpness of the tip. Therefore, when the firing process is performed at the same temperature, wafers with sharper tips are expected to exhibit better electrode characteristics.
Hyebin Han; Dongjin Choi; Sujeong Jeong; DongKyun Kang; Hyunjung Park; Soohyun Bae; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. Effects of surface morphology on Ag crystallite formation in screen-printed multi-crystalline Si solar cells. Materials Science in Semiconductor Processing 2021, 128, 105759 .
AMA StyleHyebin Han, Dongjin Choi, Sujeong Jeong, DongKyun Kang, Hyunjung Park, Soohyun Bae, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim. Effects of surface morphology on Ag crystallite formation in screen-printed multi-crystalline Si solar cells. Materials Science in Semiconductor Processing. 2021; 128 ():105759.
Chicago/Turabian StyleHyebin Han; Dongjin Choi; Sujeong Jeong; DongKyun Kang; Hyunjung Park; Soohyun Bae; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. 2021. "Effects of surface morphology on Ag crystallite formation in screen-printed multi-crystalline Si solar cells." Materials Science in Semiconductor Processing 128, no. : 105759.
The etching of Si wafers significantly influences the efficiency of photovoltaic devices. Texturing can effectively decrease front surface reflection and improve device performance. Saw damage removal (SDR) is necessary to yields uniform random pyramidal surfaces without the appearance of saw marks, it entails significant consumption of chemical solutions and complicated cleaning steps. Herein, an alternative process of pre-texturing thermal treatment was carried out at 800 °C for 10 min, followed by anisotropic texturing, and a uniform pyramidal surface over a large area of the textured surface was obtained without saw marks. Compared with that of as-cut mono-Si wafers (30.7%), the weighted average reflectance of the samples textured with or without thermal treatment decreased to 11.2% and 11.9%, respectively, and further to 3% and 3.4%, respectively, when anti-reflection coatings were applied. In addition, saw marks on the wafer surface were used as gettering sites during thermal treatment, and the bulk lifetime was more than doubled from 42.6 µs before the treatment to 93.8 µs after. The simple, SDR-free method presented herein for enhancing the textural uniformity of Si wafers and, hence, solar cell performance, can be employed on an industrial scale without necessitating additional investment in equipment.
Yujin Jung; Kwanhong Min; Soohyun Bae; Myeongseob Sim; Yoonmook Kang; Haeseok Lee; Donghwan Kim. Pre-Texturing Thermal Treatment for Saw-Damage-Removal-Free Wet Texturing of Monocrystalline Silicon Wafers. Energies 2020, 13, 6610 .
AMA StyleYujin Jung, Kwanhong Min, Soohyun Bae, Myeongseob Sim, Yoonmook Kang, Haeseok Lee, Donghwan Kim. Pre-Texturing Thermal Treatment for Saw-Damage-Removal-Free Wet Texturing of Monocrystalline Silicon Wafers. Energies. 2020; 13 (24):6610.
Chicago/Turabian StyleYujin Jung; Kwanhong Min; Soohyun Bae; Myeongseob Sim; Yoonmook Kang; Haeseok Lee; Donghwan Kim. 2020. "Pre-Texturing Thermal Treatment for Saw-Damage-Removal-Free Wet Texturing of Monocrystalline Silicon Wafers." Energies 13, no. 24: 6610.
Yujin Jung; Jongwon Ko; Soohyun Bae; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. Effective Surface Texturing of Diamond-Wire-Sawn Multicrystalline Silicon Wafers Via Crystallization of the Native Surface Amorphous Layer. IEEE Journal of Photovoltaics 2020, 11, 43 -49.
AMA StyleYujin Jung, Jongwon Ko, Soohyun Bae, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim. Effective Surface Texturing of Diamond-Wire-Sawn Multicrystalline Silicon Wafers Via Crystallization of the Native Surface Amorphous Layer. IEEE Journal of Photovoltaics. 2020; 11 (1):43-49.
Chicago/Turabian StyleYujin Jung; Jongwon Ko; Soohyun Bae; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. 2020. "Effective Surface Texturing of Diamond-Wire-Sawn Multicrystalline Silicon Wafers Via Crystallization of the Native Surface Amorphous Layer." IEEE Journal of Photovoltaics 11, no. 1: 43-49.
The introduction of diamond wire sawing (DWS) technology has resulted in significant cost reduction in the fabrication of crystalline silicon wafers. However, the DWS process results in parallel wheel marks, saw damage, and formation of an amorphous silicon layer on the surface, which causes difficultly in effectively forming the desired surface texture using conventional acidic etching (also known isotropic etching) techniques for multicrystalline silicon (mc-Si) wafers. In this study, we propose a novel pretreatment grinding (NPTG) technique as a method to address such issues. This is a relatively simple and inexpensive method that does not utilize processes that require the use of expensive equipment, such as vacuum equipment. Additionally, it makes use of environment-friendly procedures that do not require materials such as metal catalysts and additives that cause environmental pollution. The proposed NPTG method provides a good surface topology for effective texturing using a conventional acidic etching solution, and as a result, a uniform texture can be applied to DWS mc-Si wafers. Under the optimized experimental conditions in this study, a weighted average reflectance of 22.63% was achieved after the NPTG was applied. This reflected 6.67% less light than the 29.3% after conventional acidic texturing without the NPTG using DWS mc-Si wafers. Further, a solar cell fabricated using the DWS mc-Si wafers treated with the NPTG method achieved a cell efficiency of approximately 19.2%.
Yujin Jung; Kwan Hong Min; Soohyun Bae; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. 19.2%-Efficient Multicrystalline Silicon Solar Cells via Additive-Free Mechanical Grinding Surface Pretreatment for Diamond-Wire-Sawn Wafers. IEEE Journal of Photovoltaics 2020, 11, 36 -42.
AMA StyleYujin Jung, Kwan Hong Min, Soohyun Bae, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim. 19.2%-Efficient Multicrystalline Silicon Solar Cells via Additive-Free Mechanical Grinding Surface Pretreatment for Diamond-Wire-Sawn Wafers. IEEE Journal of Photovoltaics. 2020; 11 (1):36-42.
Chicago/Turabian StyleYujin Jung; Kwan Hong Min; Soohyun Bae; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. 2020. "19.2%-Efficient Multicrystalline Silicon Solar Cells via Additive-Free Mechanical Grinding Surface Pretreatment for Diamond-Wire-Sawn Wafers." IEEE Journal of Photovoltaics 11, no. 1: 36-42.
In a multicrystalline silicon (mc-Si) wafer, trapping effects frequently occur in the carrier lifetime measurement based on the quasi-steady-state photoconductance (QSSPC) technique. This affects the accurate measurement of the carrier lifetime of an mc-Si solar cell by causing distortions at a low injection level close to the Pmax point. Therefore, it is necessary to understand this effect and effectively minimize the trapping-center density. In this study, the variations in the minority carrier-trapping effect of hydrogen at different annealing temperatures in an mc-Si were observed using QSSPC, time-of-flight secondary ion mass spectroscopy, and atom probe tomography. A trapping effect was confirmed and occurred in the grain boundary area, and the effect was reduced by hydrogen. Thus, in an mc-Si wafer, effective hydrogen passivation on the grain area and grain boundary is crucial and was experimentally proven to minimize the distortion of the carrier lifetime.
Yujin Jung; Kwan Hong Min; Soohyun Bae; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee. Variations in Minority Carrier-Trapping Effects Caused by Hydrogen Passivation in Multicrystalline Silicon Wafer. Energies 2020, 13, 5783 .
AMA StyleYujin Jung, Kwan Hong Min, Soohyun Bae, Yoonmook Kang, Donghwan Kim, Hae-Seok Lee. Variations in Minority Carrier-Trapping Effects Caused by Hydrogen Passivation in Multicrystalline Silicon Wafer. Energies. 2020; 13 (21):5783.
Chicago/Turabian StyleYujin Jung; Kwan Hong Min; Soohyun Bae; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee. 2020. "Variations in Minority Carrier-Trapping Effects Caused by Hydrogen Passivation in Multicrystalline Silicon Wafer." Energies 13, no. 21: 5783.
The status and problems of upscaling research on perovskite solar cells, which must be addressed for commercialization efforts to be successful, are investigated. An 804 cm2 perovskite solar module has been reported with 17.9% efficiency, which is significantly lower than the champion perovskite solar cell efficiency of 25.2% reported for a 0.09 cm2 aperture area. For the realization of upscaling high‐quality perovskite solar cells, the upscaling and development history of conventional silicon, copper indium gallium sulfur/selenide and CdTe solar cells, which are already commercialized with modules of sizes up to ≈25 000 cm2, are reviewed. GaAs, organic, dye‐sensitized solar cells and perovskite/silicon tandem solar cells are also reviewed. The similarities of the operating mechanisms between the various solar cells and the origin of different development pathway are investigated, and the ideal upscaling direction of perovskite solar cells is subsequently proposed. It is believed that lessons learned from the historical analysis of various solar cells provide a fundamental diagnosis of relative and absolute development status of perovskite solar cells. The unique perspective proposed here can pave the way toward the upscaling of perovskite solar cells.
Sang‐Won Lee; Soohyun Bae; Donghwan Kim; Hae‐Seok Lee. Historical Analysis of High‐Efficiency, Large‐Area Solar Cells: Toward Upscaling of Perovskite Solar Cells. Advanced Materials 2020, 32, e2002202 .
AMA StyleSang‐Won Lee, Soohyun Bae, Donghwan Kim, Hae‐Seok Lee. Historical Analysis of High‐Efficiency, Large‐Area Solar Cells: Toward Upscaling of Perovskite Solar Cells. Advanced Materials. 2020; 32 (51):e2002202.
Chicago/Turabian StyleSang‐Won Lee; Soohyun Bae; Donghwan Kim; Hae‐Seok Lee. 2020. "Historical Analysis of High‐Efficiency, Large‐Area Solar Cells: Toward Upscaling of Perovskite Solar Cells." Advanced Materials 32, no. 51: e2002202.
Since the kerfless wafer method for manufacturing multicrystalline silicon (mc-Si) wafers does not involve a sawing process, there occurs no saw damage on the surface, and the product is characterized by a flat surface morphology. These wafers cannot be effectively textured under the conditions of a conventional acidic etching solution with stability or efficiency because the surfaces are free of the surface damage caused by sawing. The texturing process developed in this article uses a conventional acidic etching solution without additives and a metal catalyst; the resulting process is a novel double acidic texturing (DAT) process capable of texturing using hydrofluoric acid (HF), HNO $_{3}$ , CH $_{3}$ COOH, and deionized water. The kerfless wafers treated with this novel texturing treatment had a weighted average reflectance (R $_{w}$ ) of 25.40%, which is ∼5.76% less than that of kerfless wafers textured under conventional acidic texturing conditions (R $_{w}$ = ∼31.16%). A solar cell manufactured with the new DAT process showed an enhanced short-circuit current density (+2.65 mA·cm−2), fill factor (+3.87%), and efficiency (+2.18%) than those of a cell fabricated without using this novel double treatment.
Yujin Jung; Soohyun Bae; Hae-Seok Lee; Donghwan Kim; Yoonmook Kang. Novel Double Acidic Texturing Process for Saw-Damage-Free Kerfless Multicrystalline Silicon Wafers. IEEE Journal of Photovoltaics 2020, 10, 1545 -1551.
AMA StyleYujin Jung, Soohyun Bae, Hae-Seok Lee, Donghwan Kim, Yoonmook Kang. Novel Double Acidic Texturing Process for Saw-Damage-Free Kerfless Multicrystalline Silicon Wafers. IEEE Journal of Photovoltaics. 2020; 10 (6):1545-1551.
Chicago/Turabian StyleYujin Jung; Soohyun Bae; Hae-Seok Lee; Donghwan Kim; Yoonmook Kang. 2020. "Novel Double Acidic Texturing Process for Saw-Damage-Free Kerfless Multicrystalline Silicon Wafers." IEEE Journal of Photovoltaics 10, no. 6: 1545-1551.
Since the temperature of a photovoltaic (PV) module is not consistent as it was estimated at a standard test condition, the thermal stability of the solar cell parameters determines the temperature dependence of the PV module. Fill factor loss analysis of crystalline silicon solar cell is one of the most efficient methods to diagnose the dominant problem, accurately. In this study, the fill factor analysis method and the double-diode model of a solar cell was applied to analyze the effect of J01, J02, Rs, and Rsh on the fill factor in details. The temperature dependence of the parameters was compared through the passivated emitter rear cell (PERC) of the industrial scale solar cells. As a result of analysis, PERC cells showed different temperature dependence for the fill factor loss of the J01 and J02 as temperatures rose. In addition, we confirmed that fill factor loss from the J01 and J02 at elevated temperature depends on the initial state of the solar cells. The verification of the fill factor loss analysis was conducted by comparing to the fitting results of the injection dependent-carrier lifetime.
Kwan Hong Min; Taejun Kim; Min Gu Kang; Hee-Eun Song; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim; Sungeun Park; Sang Hee Lee. An Analysis of Fill Factor Loss Depending on the Temperature for the Industrial Silicon Solar Cells. Energies 2020, 13, 1 .
AMA StyleKwan Hong Min, Taejun Kim, Min Gu Kang, Hee-Eun Song, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim, Sungeun Park, Sang Hee Lee. An Analysis of Fill Factor Loss Depending on the Temperature for the Industrial Silicon Solar Cells. Energies. 2020; 13 (11):1.
Chicago/Turabian StyleKwan Hong Min; Taejun Kim; Min Gu Kang; Hee-Eun Song; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim; Sungeun Park; Sang Hee Lee. 2020. "An Analysis of Fill Factor Loss Depending on the Temperature for the Industrial Silicon Solar Cells." Energies 13, no. 11: 1.
A thin silicon oxide (SiOx) layer (thickness: 1.5–2.0 nm) formed at an Al2O3/Si interface can enhance the interface properties. However, it is challenging to control the characteristics of thin SiOx layers because SiOx forms naturally during Al2O3 deposition on Si substrates. In this study, a ~1.5 nm-thick SiOx layer was inserted between Al2O3 and Si substrates by wet chemical oxidation to improve the passivation properties. The acidic solutions used for wet chemical oxidation were HCl:H2O2:H2O, H2SO4:H2O2:H2O, and HNO3. The thicknesses of SiOx layers formed in the acidic solutions were ~1.48, ~1.32, and ~1.50 nm for SiOx-HCl, SiOx-H2SO4, and SiOx-HNO3, respectively. The leakage current characteristics of SiOx-HNO3 were better than those of the oxide layers formed in the other acidic solutions. After depositing a ~10 nm-thick Al2O3 on an SiOx-acidic/Si structure, we measured the effective carrier lifetime using quasi steady-state photoconductance and examined the interfacial properties of Al2O3/SiOx-acidic/Si using surface carrier lifetime simulation and capacitance–voltage measurement. The effective carrier lifetime of Al2O3/SiOx-HNO3/Si was relatively high (~400 μs), resulting from the low surface defect density (2.35–2.88 × 1010 cm−2eV−1). The oxide layer inserted between Al2O3 and Si substrates by wet chemical oxidation helped improve the Al2O3/Si interface properties.
Kwan Hong Min; Sungjin Choi; Myeong Sang Jeong; Sungeun Park; Min Gu Kang; Jeong In Lee; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee; Hee-Eun Song. Wet Chemical Oxidation to Improve Interfacial Properties of Al2O3/Si and Interface Analysis of Al2O3/SiOx/Si Structure Using Surface Carrier Lifetime Simulation and Capacitance–Voltage Measurement. Energies 2020, 13, 1803 .
AMA StyleKwan Hong Min, Sungjin Choi, Myeong Sang Jeong, Sungeun Park, Min Gu Kang, Jeong In Lee, Yoonmook Kang, Donghwan Kim, Hae-Seok Lee, Hee-Eun Song. Wet Chemical Oxidation to Improve Interfacial Properties of Al2O3/Si and Interface Analysis of Al2O3/SiOx/Si Structure Using Surface Carrier Lifetime Simulation and Capacitance–Voltage Measurement. Energies. 2020; 13 (7):1803.
Chicago/Turabian StyleKwan Hong Min; Sungjin Choi; Myeong Sang Jeong; Sungeun Park; Min Gu Kang; Jeong In Lee; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee; Hee-Eun Song. 2020. "Wet Chemical Oxidation to Improve Interfacial Properties of Al2O3/Si and Interface Analysis of Al2O3/SiOx/Si Structure Using Surface Carrier Lifetime Simulation and Capacitance–Voltage Measurement." Energies 13, no. 7: 1803.
For screen-printed silicon solar cells, optimization of the contact characteristics between the front metal electrode and silicon is very significant for realizing high efficiency. As technology advances, the solar cell efficiency has been steadily increased. Especially, as surface recombination becomes more important in high efficiency solar cells, understanding and controlling recombination in the metal contact area are necessary. Recombination at the metal-silicon interface is a major cause of the drop in the open-circuit voltage (Voc) of a solar cell. Thus far, the study of electrodes in silicon solar cells has been largely aimed at reducing the series resistance, and few studies on recombination due to electrodes have been performed. Quantitatively evaluating the recombination in electrodes to assess the effect on the efficiency is expected to become more important in the near future. In this paper, the contact characteristics of a screen-printed silver electrode and silicon interface were analyzed using saturation current density (Jo) measurements according to the surface doping concentration and firing temperature. The effects of the contact characteristics on Voc and recombination were also investigated. Experimental results showed that Jo.pass decreased with decreasing surface doping concentration and Jo.metal increased with increasing surface doping concentration and firing temperature. For quantitative analysis of Jo.metal, the size and distribution of Ag crystallites were observed using SEM and TEM, and the Ag concentration was analyzed by ICP-OES measurements. The larger Jo.metal was, the higher the Ag crystallite concentration, indicating that the Ag crystallites under the electrode increased Jo.metal. The effect of Jo.metal on the electrical characteristics of the solar cell was analyzed by calculating the change in the surface recombination velocity and the decreased width of Voc. Through this study, the recombination in the metallized area, which is expected to become increasingly important, and particularly the effects of the doping profile of the emitter region and silver crystallites on the surface recombination were quantitatively assessed. The amount of silver crystallites on the silicon wafer was quantitatively analyzed.
Myeong Sang Jeong; Kwan Hong Min; Sungjin Choi; Min Gu Kang; Kyung Taek Jeong; Eun Tae Lee; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee; Hee-Eun Song; Sungeun Park. Correlation between the open-circuit voltage and recombination loss at metal-silicon interfaces of crystalline silicon solar cells. Solar Energy Materials and Solar Cells 2020, 210, 110519 .
AMA StyleMyeong Sang Jeong, Kwan Hong Min, Sungjin Choi, Min Gu Kang, Kyung Taek Jeong, Eun Tae Lee, Yoonmook Kang, Donghwan Kim, Hae-Seok Lee, Hee-Eun Song, Sungeun Park. Correlation between the open-circuit voltage and recombination loss at metal-silicon interfaces of crystalline silicon solar cells. Solar Energy Materials and Solar Cells. 2020; 210 ():110519.
Chicago/Turabian StyleMyeong Sang Jeong; Kwan Hong Min; Sungjin Choi; Min Gu Kang; Kyung Taek Jeong; Eun Tae Lee; Yoonmook Kang; Donghwan Kim; Hae-Seok Lee; Hee-Eun Song; Sungeun Park. 2020. "Correlation between the open-circuit voltage and recombination loss at metal-silicon interfaces of crystalline silicon solar cells." Solar Energy Materials and Solar Cells 210, no. : 110519.
Recently, titanium oxide has been widely investigated as a carrier-selective contact material for silicon solar cells. Herein, titanium oxide films were fabricated via simple deposition methods involving thermal evaporation and oxidation. This study focuses on characterizing an electron-selective passivated contact layer with this oxidized method. Subsequently, the SiO2/TiO2 stack was examined using high-resolution transmission electron microscopy. The phase and chemical composition of the titanium oxide films were analyzed using X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The passivation quality of each layer was confirmed by measuring the carrier lifetime using quasi-steady-state photoconductance, providing an implied open circuit voltage of 644 mV. UV–vis spectroscopy and UV photoelectron spectroscopy analyses demonstrated the band alignment and carrier selectivity of the TiO2 layers. Band offsets of ~0.33 and ~2.6 eV relative to the conduction and valence bands, respectively, were confirmed for titanium oxide and the silicon interface.
Changhyun Lee; Soohyun Bae; Hyunjung Park; Dongjin Choi; Hoyoung Song; Hyunju Lee; Yoshio Ohshita; Donghwan Kim; Yoonmook Kang; Hae-Seok Lee. Properties of Thermally Evaporated Titanium Dioxide as an Electron-Selective Contact for Silicon Solar Cells. Energies 2020, 13, 678 .
AMA StyleChanghyun Lee, Soohyun Bae, Hyunjung Park, Dongjin Choi, Hoyoung Song, Hyunju Lee, Yoshio Ohshita, Donghwan Kim, Yoonmook Kang, Hae-Seok Lee. Properties of Thermally Evaporated Titanium Dioxide as an Electron-Selective Contact for Silicon Solar Cells. Energies. 2020; 13 (3):678.
Chicago/Turabian StyleChanghyun Lee; Soohyun Bae; Hyunjung Park; Dongjin Choi; Hoyoung Song; Hyunju Lee; Yoshio Ohshita; Donghwan Kim; Yoonmook Kang; Hae-Seok Lee. 2020. "Properties of Thermally Evaporated Titanium Dioxide as an Electron-Selective Contact for Silicon Solar Cells." Energies 13, no. 3: 678.
In this study, perovskite thin films (PFs) were conformally deposited on 100 cm2 textured silicon substrates using a two-step vacuum process. The PFs were fabricated by converting thin films of a sputtered-PbO precursor using the chemical vapor deposition process. The conversion of PbO thin films into PFs was confirmed by X-ray diffractometry. The uniformity of reflectance and thickness was higher than 86% and 92%, respectively, on 100 cm2 textured substrate. We applied methylammonium vapor treatment for complete conversion without residual layer and the power conversion efficiency was 10.2% on a glass/FTO/TiO2/MAPbI3/Spiro-MeOTAD/Au structure.
Jae-Keun Hwang; Sang-Won Lee; Wonkyu Lee; Soohyun Bae; Kyungjin Cho; Seongtak Kim; Solhee Lee; Ji Yeon Hyun; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. Conformal perovskite films on 100 cm2 textured silicon surface using two-step vacuum process. Thin Solid Films 2019, 693, 137694 .
AMA StyleJae-Keun Hwang, Sang-Won Lee, Wonkyu Lee, Soohyun Bae, Kyungjin Cho, Seongtak Kim, Solhee Lee, Ji Yeon Hyun, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim. Conformal perovskite films on 100 cm2 textured silicon surface using two-step vacuum process. Thin Solid Films. 2019; 693 ():137694.
Chicago/Turabian StyleJae-Keun Hwang; Sang-Won Lee; Wonkyu Lee; Soohyun Bae; Kyungjin Cho; Seongtak Kim; Solhee Lee; Ji Yeon Hyun; Yoonmook Kang; Hae-Seok Lee; Donghwan Kim. 2019. "Conformal perovskite films on 100 cm2 textured silicon surface using two-step vacuum process." Thin Solid Films 693, no. : 137694.
Al2O3/SiNx stack passivation layers are among the most popular layers used for commercial silicon solar cells. In particular, aluminum oxide has a high negative charge, while the SiNx film is known to supply hydrogen as well as impart antireflective properties. Although there are many experimental results that show that the passivation characteristics are lowered by using the stack passivation layer, the cause of the passivation is not yet understood. In this study, we investigated the passivation characteristics of Al2O3/SiNx stack layers. To identify the hydrogenation effect, we analyzed the hydrogen migration with atom probe tomography by comparing the pre-annealing and post-annealing treatments. For chemical passivation, capacitance-voltage measurements were used to confirm the negative fixed charge density due to heat treatment. Moreover, the field-effect passivation was understood by confirming changes in the Al2O3 structure using electron energy-loss spectroscopy.
Ji Yeon Hyun; Soohyun Bae; Yoon Chung Nam; DongKyun Kang; Sang-Won Lee; Donghwan Kim; Jooyoung Park; Yoonmook Kang; Hae-Seok Lee. Surface Passivation of Boron Emitters on n-Type Silicon Solar Cells. Sustainability 2019, 11, 3784 .
AMA StyleJi Yeon Hyun, Soohyun Bae, Yoon Chung Nam, DongKyun Kang, Sang-Won Lee, Donghwan Kim, Jooyoung Park, Yoonmook Kang, Hae-Seok Lee. Surface Passivation of Boron Emitters on n-Type Silicon Solar Cells. Sustainability. 2019; 11 (14):3784.
Chicago/Turabian StyleJi Yeon Hyun; Soohyun Bae; Yoon Chung Nam; DongKyun Kang; Sang-Won Lee; Donghwan Kim; Jooyoung Park; Yoonmook Kang; Hae-Seok Lee. 2019. "Surface Passivation of Boron Emitters on n-Type Silicon Solar Cells." Sustainability 11, no. 14: 3784.
The illuminated current-voltage characteristics of Cu(In,Ga)(S,Se)2 (CIGSSe) thin film solar cells fabricated using two different buffer layer processes: chemical bath deposition (CBD) and atomic layer deposition (ALD) were investigated. The CIGSSe solar cell with the ALD buffer showed comparable conversion efficiency to the CIGSSe solar cell with CBD buffer but lower shunt resistance even though it showed lower point shunt defect density as measured in electroluminescence. The shunt paths were investigated in detail by capturing the high-resolution dark lock-in thermography images, resolving the shunt resistance contributions of the scribing patterns (P1, P3), and depth profiling of the constituent elements. It was found that the concentration of Na from the soda-lime glass substrate played a key role in controlling the shunt paths. In the ALD process, Na segregated at the surface of CIGSSe and contributed to the increase in the shunt current through P1 and P3, resulting in a reduction in the fill factor of the CIGSSe solar cells.
Chan Bin Mo; Se Jin Park; Soohyun Bae; Mi-Hwa Lim; Junggyu Nam; Dongseop Kim; JungYup Yang; Dongchul Suh; Byoung Koun Min; Donghwan Kim; Yoonmook Kang; Young-Su Kim; Hae-Seok Lee. Impact of Buffer Layer Process and Na on Shunt Paths of Monolithic Series-connected CIGSSe Thin Film Solar Cells. Scientific Reports 2019, 9, 1 -11.
AMA StyleChan Bin Mo, Se Jin Park, Soohyun Bae, Mi-Hwa Lim, Junggyu Nam, Dongseop Kim, JungYup Yang, Dongchul Suh, Byoung Koun Min, Donghwan Kim, Yoonmook Kang, Young-Su Kim, Hae-Seok Lee. Impact of Buffer Layer Process and Na on Shunt Paths of Monolithic Series-connected CIGSSe Thin Film Solar Cells. Scientific Reports. 2019; 9 (1):1-11.
Chicago/Turabian StyleChan Bin Mo; Se Jin Park; Soohyun Bae; Mi-Hwa Lim; Junggyu Nam; Dongseop Kim; JungYup Yang; Dongchul Suh; Byoung Koun Min; Donghwan Kim; Yoonmook Kang; Young-Su Kim; Hae-Seok Lee. 2019. "Impact of Buffer Layer Process and Na on Shunt Paths of Monolithic Series-connected CIGSSe Thin Film Solar Cells." Scientific Reports 9, no. 1: 1-11.
We have investigated the effects of chemical rounding (CR) on the surface passivation and/or antireflection performance of AlOx- and AlOx/SiNx:H stack-passivated pyramid textured p+-emitters with two different boron doping concentrations, and on the performance of bifacial n-PERT Si solar cells with a front pyramid textured p+-emitter. From experimental results, we found that chemical rounding markedly enhances the passivation performance of AlOx layers on pyramid textured p+-emitters, and the level of performance enhancement strongly depends on boron doping concentration. Meanwhile, chemical rounding increases solar-weighted reflectance (RSW) from ∼2.5 to ∼3.7% for the AlOx/SiNx:H stack-passivated pyramid textured p+-emitters after 200-sec chemical rounding. Consequently, compared to non-rounded bifacial n-PERT Si cells, the short circuit current density Jsc of 200-sec-rounded bifacial n-PERT Si cells with ∼60 and ∼100 Ω/sq p+-emitters is reduced by 0.8 and 0.6 mA/cm2, respectively under front p+-emitter side illumination. However, the loss in the short circuit current density Jsc is fully offset by the increased fill factor FF by 0.8 and 1.5% for the 200-sec-rounded cells with ∼60 and ∼100 Ω/sq p+-emitters, respectively. In particular, the cell efficiency of the 200-sec-rounded cells with a ∼100 Ω/sq p+-emitter is enhanced as a result, compared to that of the non-rounded cells. Based on our results, it could be expected that the cell efficiency of bifacial n-PERT Si cells would be improved without additional complicated and costly processes if chemical rounding and boron doping processes can be properly optimized.
Inseol Song; Hyunju Lee; Sang-Won Lee; Soohyun Bae; Ji Yeon Hyun; Yoonmook Kang; Hae-Seok Lee; Yoshio Ohshita; Atsushi Ogura; Donghwan Kim. Potential of chemical rounding for the performance enhancement of pyramid textured p-type emitters and bifacial n-PERT Si cells. Current Applied Physics 2018, 18, 1268 -1274.
AMA StyleInseol Song, Hyunju Lee, Sang-Won Lee, Soohyun Bae, Ji Yeon Hyun, Yoonmook Kang, Hae-Seok Lee, Yoshio Ohshita, Atsushi Ogura, Donghwan Kim. Potential of chemical rounding for the performance enhancement of pyramid textured p-type emitters and bifacial n-PERT Si cells. Current Applied Physics. 2018; 18 (11):1268-1274.
Chicago/Turabian StyleInseol Song; Hyunju Lee; Sang-Won Lee; Soohyun Bae; Ji Yeon Hyun; Yoonmook Kang; Hae-Seok Lee; Yoshio Ohshita; Atsushi Ogura; Donghwan Kim. 2018. "Potential of chemical rounding for the performance enhancement of pyramid textured p-type emitters and bifacial n-PERT Si cells." Current Applied Physics 18, no. 11: 1268-1274.