The Experts below are selected from a list of 982110 Experts worldwide ranked by ideXlab platform
Prabir Kanti Basu - One of the best experts on this subject based on the ideXlab platform.
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regulated low cost pre treatment step for surface Texturization of large area industrial single crystalline silicon solar cell
Solar Energy Materials and Solar Cells, 2010Co-Authors: Prabir Kanti Basu, N Udayakumar, H Dhasmana, Firoz Khan, D K ThakurAbstract:Conventional pre-treatment process for saw damage removal before Texturization of monocrystalline silicon wafers is by higher concentration (6–10%) caustic etch at 50–60 °C. In this paper a novel low cost approach for this pre-treatment of surface texture by a new composition of hot sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) solution is reported for industrial large area, high efficiency, single crystalline silicon solar cells. The moderate silicon etching rate of hot NaOH–NaOCl solution generates a better control on removal of damaged surface. This new damage etching process also helps in the formation of optimized pyramidal structure on silicon wafer during Texturization. This process is highly suitable for thin starting raw wafers with thicknesses in 160–200 μm range used by most of cell manufacturing industries. Substantial reduction of yield loss due to breakage of wafers is achieved by using this modified process. Optimized recipe of this surface Texturization process is ascertained by the Scanning Electron Microscopic (SEM) study of front textured surface on non-metallized and metallized areas. Also reflectivity, cell dark and illuminated voltage–current characteristic measurements validate the superiority of this process to the existing one, which finally leads to low cost, improved quality solar cells for any monocrystalline PV industry.
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a new energy efficient environment friendly and high productive Texturization process of industrial multicrystalline silicon solar cells
Renewable Energy, 2009Co-Authors: Prabir Kanti Basu, N Udayakumar, H Dhasmana, D K ThakurAbstract:A new Texturization process based on a uniform, isotropic and slow removal of silicon, using a composition of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) solution at an elevated temperature is developed recently for multicrystalline silicon solar cells. This process is applied in optimized condition in regular industrial production line and it immediately replaces the old popular industrial process of Texturization using a combination of NaOH solution, alcoholic NaOH solution and hydrochloric acid solution in different steps at a higher temperature. Also the gain in solar cell efficiency at global AM1.5 spectrum, 1 SUN intensity condition is nearly 10% in final value. In addition, it has become finally an energy efficient and environment friendly Texturization process for large area multicrystalline silicon solar cells for commercial use. In this paper the cost effectiveness and environment friendly aspects of the proposed process have been studied in detail along with the surface texture analysis of wafers with SEM and AFM micrographs to substantiate the reasons behind the above facts.
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a novel low cost Texturization method for large area commercial mono crystalline silicon solar cells
Solar Energy Materials and Solar Cells, 2006Co-Authors: U. Gangopadhyay, S K Dhungel, U Manna, Prabir Kanti Basu, M Banerjee, H Saha, Junsin YiAbstract:Abstract Texturization of mono-crystalline silicon for solar cell fabrication is still a key issue due to consumption of large amount of costly isopropyl alcohol (IPA) in conventional NaOH/KOH solution. The need of IPA arises due to the improvement in the uniformity of pyramidal structures and elimination of spots caused by bubbles sticking on the wafer surface during the Texturization process. We investigated a new Texturization technique for mono-crystalline silicon solar cells with tribasic sodium phosphate (Na 3 PO 4 , 12H 2 O) solution with much less amount of IPA. The proposed Texturization method of this paper is cost effective due to reduction in the consumption of expensive IPA. The cost comparison of our novel Texturization approach with conventional NaOH Texturization has also been reported in this paper. We are reporting for the first time such a novel approach of using tribasic sodium phosphate for Texturization of mono-crystalline silicon surface with which solar cells of efficiency 14–14.8% are fabricated with more than 90% yield.
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low cost Texturization of large area crystalline silicon solar cells using hydrazine mono hydrate for industrial use
Renewable Energy, 2006Co-Authors: U. Gangopadhyay, S K Dhungel, Prabir Kanti Basu, Junsin YiAbstract:Reduction in optical losses in mono-crystalline silicon solar cells by surface texturing is one of the important issues of modern silicon photovoltaics. In order to achieve good uniformity in pyramidal structures on the silicon surface, a mixture of sodium hydroxide (NaOH) or potassium hydroxide (KOH) and isopropyl alcohol (IPA) is generally used during Texturization of mono-crystalline silicon solar cell. However, due to the high cost of IPA, there is always a search for alternate chemical which plays the same role as IPA during Texturization for industrial solar cell production. For a better Texturization, the interfacial energy between silicon and ionized electrolyte of chemical solution should be reduced to achieve sufficient wettability of the silicon surface, which will enhance the pyramid nucleation. In this work, we have investigated the role of hydrazine mono-hydrate as a surface-active additive, which supplies OH− ions after its dissociation. Our process cuts down the IPA consumption during texturing without any loss in uniformity of textured pyramids. We are the first to report the novel idea to add hydrazine mono-hydrate in NaOH solution for texturing mono-crystalline silicon surface to fabricate solar cells with more than 85% yield in the efficiency range of 14.5–15.3%.
Yoji Saito - One of the best experts on this subject based on the ideXlab platform.
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maskless Texturization of phosphorus diffused layers for crystalline si solar cells by plasmaless dry etching with chlorine trifluoride gas
Solar Energy Materials and Solar Cells, 2010Co-Authors: Hayato Kohata, Yoji SaitoAbstract:Abstract Reflection loss of silicon solar cells can be reduced by texturing the surfaces. We investigated the Texturization process for crystalline Si solar cells using chlorine trifluoride (ClF3) gas treatments. Reflectance of textured surfaces was reduced to below 10% at the wavelength of 600 nm. However, the efficiency increase for the random-textured solar cells was below 10% and was much less than the increase for the absorbed light in the substrates after Texturization. In this study, we tried to improve the electrical characteristics of textured cells by modifying the fabrication process. The diffused layers were treated with chlorine trifluoride gas to form textured structures. The reflectance of the textured surface, obtained by the maskless etching with ClF3, was approximately 17.8% at the wavelength of 600 nm. Solar cells with textured substrates were fabricated and their improved performance was demonstrated.
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honeycomb textured structures on crystalline silicon surfaces for solar cells by spontaneous dry etching with chlorine trifluoride gas
Solar Energy Materials and Solar Cells, 2007Co-Authors: Yoji Saito, Takeshi KosugeAbstract:Abstract Reflection loss of silicon solar cells can be reduced by Texturization of the surfaces. In this study, single- and multi-crystalline silicon substrates were treated with chlorine trifluoride (ClF3) to create honeycomb-textured structures. We investigated surface structures and optical properties of the textured surfaces. By the treatment with ClF3 gas, the reflectance of the textured surface without anti-reflection coating was obtained to be below 20% at wavelengths between 300 and 800 nm. The solar cells using the textured substrates were fabricated and their improved performances were demonstrated.
D K Thakur - One of the best experts on this subject based on the ideXlab platform.
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regulated low cost pre treatment step for surface Texturization of large area industrial single crystalline silicon solar cell
Solar Energy Materials and Solar Cells, 2010Co-Authors: Prabir Kanti Basu, N Udayakumar, H Dhasmana, Firoz Khan, D K ThakurAbstract:Conventional pre-treatment process for saw damage removal before Texturization of monocrystalline silicon wafers is by higher concentration (6–10%) caustic etch at 50–60 °C. In this paper a novel low cost approach for this pre-treatment of surface texture by a new composition of hot sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) solution is reported for industrial large area, high efficiency, single crystalline silicon solar cells. The moderate silicon etching rate of hot NaOH–NaOCl solution generates a better control on removal of damaged surface. This new damage etching process also helps in the formation of optimized pyramidal structure on silicon wafer during Texturization. This process is highly suitable for thin starting raw wafers with thicknesses in 160–200 μm range used by most of cell manufacturing industries. Substantial reduction of yield loss due to breakage of wafers is achieved by using this modified process. Optimized recipe of this surface Texturization process is ascertained by the Scanning Electron Microscopic (SEM) study of front textured surface on non-metallized and metallized areas. Also reflectivity, cell dark and illuminated voltage–current characteristic measurements validate the superiority of this process to the existing one, which finally leads to low cost, improved quality solar cells for any monocrystalline PV industry.
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a new energy efficient environment friendly and high productive Texturization process of industrial multicrystalline silicon solar cells
Renewable Energy, 2009Co-Authors: Prabir Kanti Basu, N Udayakumar, H Dhasmana, D K ThakurAbstract:A new Texturization process based on a uniform, isotropic and slow removal of silicon, using a composition of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) solution at an elevated temperature is developed recently for multicrystalline silicon solar cells. This process is applied in optimized condition in regular industrial production line and it immediately replaces the old popular industrial process of Texturization using a combination of NaOH solution, alcoholic NaOH solution and hydrochloric acid solution in different steps at a higher temperature. Also the gain in solar cell efficiency at global AM1.5 spectrum, 1 SUN intensity condition is nearly 10% in final value. In addition, it has become finally an energy efficient and environment friendly Texturization process for large area multicrystalline silicon solar cells for commercial use. In this paper the cost effectiveness and environment friendly aspects of the proposed process have been studied in detail along with the surface texture analysis of wafers with SEM and AFM micrographs to substantiate the reasons behind the above facts.
Kang L. Wang - One of the best experts on this subject based on the ideXlab platform.
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Efficiency improved by acid Texturization for multi-crystalline silicon solar cells
Solar Energy, 2011Co-Authors: Yuang Tung Cheng, Song Yeu Tsai, Zong Zhi Ye, Daw Shang Hwang, Chiu Cheng Chang, William Lee, Shun-hsyung Chang, Jyh-jier Ho, Kang L. WangAbstract:In this paper, we will show that efficiency of multi-crystalline silicon (mc-Si) solar cells may be improved by acid Texturization. In order to enhance overall efficiency of mc-Si for solar-cell applications, the surface treatment of Texturization with wet etching using appropriate solutions can improve incident light into the cell. Alkali etchant cannot produce uniformly textured surface to generate enough open circuit voltage (VOC) and high efficiency of the mc-Si due to the unavoidable grain randomly oriented with higher steps formed during etching process. Optimized acid etching conditions can be obtained by decreasing the reflectance (R) for mc-Si substrate below levels generated by alkali etching. Short-circuit current (ISC) measurements on acid textured cells reveal that current gain can be significantly enhanced by reducing reflection. The optimal acid etching ratio HF:HNO3:H2O=15:1:2.5 with etching time of 60s and lowering 42.7% of the R value can improve 112.4% of the conversion efficiency (η) of the developed solar cell. In order to obtain more detailed information of different defect region, high-resolution light beam induced current (LBIC) is applied to measure the internal quantum efficiency (IQE) and the lifetime of minority carriers. Thus, the acid texturing approach is instrumental to achieve high efficiency in mass production using relatively low-cost mc-Si as starting material with proper optimization of the fabrication steps. © 2010 Elsevier Ltd.
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efficiency improved by acid Texturization for multi crystalline silicon solar cells
Solar Energy, 2011Co-Authors: Yuang Tung Cheng, Song Yeu Tsai, Zong Zhi Ye, Daw Shang Hwang, Chiu Cheng Chang, Shun-hsyung Chang, Jyh-jier Ho, Kang L. WangAbstract:In this paper, we will show that efficiency of multi-crystalline silicon (mc-Si) solar cells may be improved by acid Texturization. In order to enhance overall efficiency of mc-Si for solar-cell applications, the surface treatment of Texturization with wet etching using appropriate solutions can improve incident light into the cell. Alkali etchant cannot produce uniformly textured surface to generate enough open circuit voltage (V{sub OC}) and high efficiency of the mc-Si due to the unavoidable grain randomly oriented with higher steps formed during etching process. Optimized acid etching conditions can be obtained by decreasing the reflectance (R) for mc-Si substrate below levels generated by alkali etching. Short-circuit current (I{sub SC}) measurements on acid textured cells reveal that current gain can be significantly enhanced by reducing reflection. The optimal acid etching ratio HF:HNO{sub 3}:H{sub 2}O = 15:1:2.5 with etching time of 60 s and lowering 42.7% of the R value can improve 112.4% of the conversion efficiency ({eta}) of the developed solar cell. In order to obtain more detailed information of different defect region, high-resolution light beam induced current (LBIC) is applied to measure the internal quantum efficiency (IQE) and the lifetime of minority carriers. Thus, the acid texturing approach is instrumentalmore » to achieve high efficiency in mass production using relatively low-cost mc-Si as starting material with proper optimization of the fabrication steps. (author)« less
U. Gangopadhyay - One of the best experts on this subject based on the ideXlab platform.
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a novel low cost Texturization method for large area commercial mono crystalline silicon solar cells
Solar Energy Materials and Solar Cells, 2006Co-Authors: U. Gangopadhyay, S K Dhungel, U Manna, Prabir Kanti Basu, M Banerjee, H Saha, Junsin YiAbstract:Abstract Texturization of mono-crystalline silicon for solar cell fabrication is still a key issue due to consumption of large amount of costly isopropyl alcohol (IPA) in conventional NaOH/KOH solution. The need of IPA arises due to the improvement in the uniformity of pyramidal structures and elimination of spots caused by bubbles sticking on the wafer surface during the Texturization process. We investigated a new Texturization technique for mono-crystalline silicon solar cells with tribasic sodium phosphate (Na 3 PO 4 , 12H 2 O) solution with much less amount of IPA. The proposed Texturization method of this paper is cost effective due to reduction in the consumption of expensive IPA. The cost comparison of our novel Texturization approach with conventional NaOH Texturization has also been reported in this paper. We are reporting for the first time such a novel approach of using tribasic sodium phosphate for Texturization of mono-crystalline silicon surface with which solar cells of efficiency 14–14.8% are fabricated with more than 90% yield.
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role of hydrazine monohydrate during Texturization of large area crystalline silicon solar cell fabrication
Solar Energy Materials and Solar Cells, 2006Co-Authors: U. Gangopadhyay, Junsin Yi, Ajoy Kandol, H SahaAbstract:Abstract Reduction of optical losses in monocrystalline silicon solar cells by surface texturing is one of the important issues of modern silicon photovoltaic. For Texturization during commercial monocrystalline silicon solar cell fabrication, a mixture of NaOH or KOH and isopropyl alcohol (IPA) is generally used in order to achieve good uniformity of pyramidal structure on the silicon surface. The interfacial energy between silicon and electrolyte should be reduced in order to achieve sufficient wettability for the silicon surface which in turn will enhance the pyramid nucleation. In this work, we have investigated the role of hydrazine monohydrate as a surface-active additive, which supplies OH− ions after dissociation. This cuts down the IPA consumption during texturing without any loss of uniformity of textured pyramid. We are probably the first group to report such a novel idea of using hydrazine monohydrate addition in NaOH solution for Texturization of solar cell. We were able to fabricate monocrystalline silicon solar cells with more than 85% yield in the range of 14–15% efficiency.
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low cost Texturization of large area crystalline silicon solar cells using hydrazine mono hydrate for industrial use
Renewable Energy, 2006Co-Authors: U. Gangopadhyay, S K Dhungel, Prabir Kanti Basu, Junsin YiAbstract:Reduction in optical losses in mono-crystalline silicon solar cells by surface texturing is one of the important issues of modern silicon photovoltaics. In order to achieve good uniformity in pyramidal structures on the silicon surface, a mixture of sodium hydroxide (NaOH) or potassium hydroxide (KOH) and isopropyl alcohol (IPA) is generally used during Texturization of mono-crystalline silicon solar cell. However, due to the high cost of IPA, there is always a search for alternate chemical which plays the same role as IPA during Texturization for industrial solar cell production. For a better Texturization, the interfacial energy between silicon and ionized electrolyte of chemical solution should be reduced to achieve sufficient wettability of the silicon surface, which will enhance the pyramid nucleation. In this work, we have investigated the role of hydrazine mono-hydrate as a surface-active additive, which supplies OH− ions after its dissociation. Our process cuts down the IPA consumption during texturing without any loss in uniformity of textured pyramids. We are the first to report the novel idea to add hydrazine mono-hydrate in NaOH solution for texturing mono-crystalline silicon surface to fabricate solar cells with more than 85% yield in the efficiency range of 14.5–15.3%.
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High-density hollow cathode plasma etching for large area multicrystalline silicon solar cells
Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE, 2002Co-Authors: W.j. Lee, I.O. Parm, Kyunghae Kim, Jack C. Lee, U. Gangopadhyay, Krishnendu Chakrabarty, J. YiAbstract:Multicrysalline silicon (mc-Si) materials are commercially important photovoltaic material. This material consists of number of grains and grain boundaries. The orientation is generally random and the size of the grain varies between a few millimeters to several centimeters. So for multicrysalline silicon, surface Texturization is not possible with help of standard NaOH/KOH or other anisotropic chemical enchant. Actually texturing for enhanced absorption in silicon has been obtained by creating randomly distributed pyramids using anisotropic wet enchants, but this works well only on single crystalline silicon because of its crystallographic orientation. Various surface Texturization method has been used during surface preparation of mc-Si solar cell research, including mechanical grinding, laser-structuring, porous silicon etching, photolithographically defined etching etc. We developed a mask less plasma texturing technique for mc-Si solar cells using high-density hollow cathode plasma etching technique. We used SF6 and O2 gases in hollow cathode plasma (HCP) dry etching process. This paper demonstrates very high plasma density of 2×1012 cm-3 at a discharge current of 20mA. Silicon etch rate of 1.3μm/min. was achieved with SF6/O2 plasma conditions of total gas pressure =50 mTorr, gas flow rate=40 sccm, and RF power=100W. In this paper, we also reported the surface etching characteristics of monocrystalline silicon and large area multicrystalline silicon (mc-Si) wafer.