The effect of hydrogen passivation on multicrystalline silicon (mc-Si) used for solar cells is described, and the mechanism of hydrogen diffusion and passivation is also investigated. Then, the hydrogen passivation pr...The effect of hydrogen passivation on multicrystalline silicon (mc-Si) used for solar cells is described, and the mechanism of hydrogen diffusion and passivation is also investigated. Then, the hydrogen passivation processes applied in industries and research laboratories are introduced. Finally the existing problems and the prospects of hydrogen passivation are reviewed.展开更多
The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additiv...The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additive for 20 minutes at 78-80~C. Samples＇ surface morphology was observed by scanning electron microscope （SEM）. It is firstly found that the etched mc-Si surface has the uniform distribution of trap pits although the morphologies of trap pits are slightly different on different crystallographic planes. Si （100） plane was covered with many small Si-mountaln ranges or long V-shape channels arranged in a crisscross pat- tern. For （110） plane and （111） plane, they were full of a lot of triangle pit-traps （or quadrilateral holes） and twisted earthworm trap pits, respectively. The measured reflectance of the sample was 20.5% at wavelength range of 400--900 nm. These results illustrate that alkaline solution modified by an additive can effectively etch out trap pits with a good trapping light effect on mc-Si surfaces. This method should be very valuable for mc-Si solar cells.展开更多
To find out the causation of inhomogeneous minority carrier lifetime distribution in high quality multicrystalline silicon （mc-Si） wafers, impurities and lattice defects were systematically studied by means of Fouri...To find out the causation of inhomogeneous minority carrier lifetime distribution in high quality multicrystalline silicon （mc-Si） wafers, impurities and lattice defects were systematically studied by means of Fourier transform infrared （FTIR） spectroscopy and metallography, Inhomogeneously distributed oxygen impurity and dislocations were demonstrated to be key leading factors, and the restriction mechanism was discussed. Scattering process caused by ionized impurities and dislocations decreased carrier mobility, while carrier concentration was not significantly affected. Measurements showed that resistivity was higher and more dispersive in low lifetime area. Solar cells were fabricated with these wafers. Cells＇ efficiency of inhomogeneous ones exhibited averagely 0.27% lower than the regular ones in absolute terms. Recombination centers and leakage loss induced by dislocations and impurities led to the reduction in shunt resistors and open-circuit voltage, and then affected the performance of cells.展开更多
大规格Al-Si合金铸锭的晶粒细化,一直是工业化生产的难点和研究的热点。重点综述了细化剂Ti和Si中毒、B与Sr毒化对合金晶粒细化的影响,并介绍了熔体强剪切(melt conditioned direct chill,MC)MC-DC铸造方式细化Al-Si合金晶粒组织的优点...大规格Al-Si合金铸锭的晶粒细化,一直是工业化生产的难点和研究的热点。重点综述了细化剂Ti和Si中毒、B与Sr毒化对合金晶粒细化的影响,并介绍了熔体强剪切(melt conditioned direct chill,MC)MC-DC铸造方式细化Al-Si合金晶粒组织的优点及局限性,并提出了亚共晶Al-Si合金晶粒细化的研究新思路和发展方向,以期为工业化半连续铸造亚共晶Al-Si合金的生产提供参考和借鉴。展开更多
本文中应用全部PECVD工艺沉积a-SiOx:H、a-SiNx:H,和a-SiOx:H/a-SiNx:H叠层系统,比较了不同钝化膜对多晶硅太阳能电池发射极和背面钝化效果,应用FGA、RTP等热处理方法对钝化膜进行处理,重点讨论了FGA(Forming gas annealing)温度和时间...本文中应用全部PECVD工艺沉积a-SiOx:H、a-SiNx:H,和a-SiOx:H/a-SiNx:H叠层系统,比较了不同钝化膜对多晶硅太阳能电池发射极和背面钝化效果,应用FGA、RTP等热处理方法对钝化膜进行处理,重点讨论了FGA(Forming gas annealing)温度和时间的长短对钝化的影响。结果表明:低温FGA对只有单面钝化膜的硅片钝化效果不明显,而在800℃下FGA有明显作用,而且钝化效果随着时间的增加呈现出先增大后减小然后再增大的现象;退火后降温环境中是否有H和降温时间对钝化效果有很大的影响,但是对于双面膜无论FGA温度高低对钝化都有帮助,文中对上述现象做了合理的解释。最后利用双面叠层钝化膜经过FGA处理后得到的多晶硅片的少子寿命达到14.2μs,比镀膜之前的3.0μs提高了11.2μs,使多晶硅太阳能电池暗电压Voc达到630mV。展开更多
Modern nuclear power plants, both newly designed generation 3 and existing generation 2 reactors, make use of passive safety systems for significant and measurable improvements in safety and reliability. Medium Pressu...Modern nuclear power plants, both newly designed generation 3 and existing generation 2 reactors, make use of passive safety systems for significant and measurable improvements in safety and reliability. Medium Pressure Safety Injection System (MP-SIS) in Tianwan Nuclear Power Plant is a typical and very important nuclear safety passive system. This paper discusses the reliability of MP-SIS on the basis of Fault Tree Analysis (FTA) with unavailability and Minimal Cut Set (MCS) calculated as two important indicators. The result illustrates that the passive MP-Safety Injection Tank barely contributes to the system’s unavailability and human interactions with Manual Valves and Motor Operated Valves have great negative impact on the reliability.展开更多
The ultra-small textured surface of multicrystalline silicon solar cell,prepared by electroless chemical-etching method,shows an excellent anti-reflection property over a wide spectral bandwidth.A novel back surface p...The ultra-small textured surface of multicrystalline silicon solar cell,prepared by electroless chemical-etching method,shows an excellent anti-reflection property over a wide spectral bandwidth.A novel back surface protection method and front surface passivation method have been used in the multicrystalline solar cells with ultra-small textured surfaces.With these improvements,the back surface remains intact after the etch process and the efficient minority lifetime is apparently increased.The test result shows that the solar cell with ultra-small textured surface can obtain better electrical performances by these improvements.展开更多
文摘The effect of hydrogen passivation on multicrystalline silicon (mc-Si) used for solar cells is described, and the mechanism of hydrogen diffusion and passivation is also investigated. Then, the hydrogen passivation processes applied in industries and research laboratories are introduced. Finally the existing problems and the prospects of hydrogen passivation are reviewed.
基金supported by the Shanghai Aerospace Foundation (Grant No. GC072003)
文摘The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additive for 20 minutes at 78-80~C. Samples＇ surface morphology was observed by scanning electron microscope （SEM）. It is firstly found that the etched mc-Si surface has the uniform distribution of trap pits although the morphologies of trap pits are slightly different on different crystallographic planes. Si （100） plane was covered with many small Si-mountaln ranges or long V-shape channels arranged in a crisscross pat- tern. For （110） plane and （111） plane, they were full of a lot of triangle pit-traps （or quadrilateral holes） and twisted earthworm trap pits, respectively. The measured reflectance of the sample was 20.5% at wavelength range of 400--900 nm. These results illustrate that alkaline solution modified by an additive can effectively etch out trap pits with a good trapping light effect on mc-Si surfaces. This method should be very valuable for mc-Si solar cells.
基金financially supported by the Department of Education of Guangdong Province(Grant No.2013CXZDA002)Guangzhou Science and Technology Department(Grant No.2014Y2-00221)
文摘To find out the causation of inhomogeneous minority carrier lifetime distribution in high quality multicrystalline silicon （mc-Si） wafers, impurities and lattice defects were systematically studied by means of Fourier transform infrared （FTIR） spectroscopy and metallography, Inhomogeneously distributed oxygen impurity and dislocations were demonstrated to be key leading factors, and the restriction mechanism was discussed. Scattering process caused by ionized impurities and dislocations decreased carrier mobility, while carrier concentration was not significantly affected. Measurements showed that resistivity was higher and more dispersive in low lifetime area. Solar cells were fabricated with these wafers. Cells＇ efficiency of inhomogeneous ones exhibited averagely 0.27% lower than the regular ones in absolute terms. Recombination centers and leakage loss induced by dislocations and impurities led to the reduction in shunt resistors and open-circuit voltage, and then affected the performance of cells.
文摘大规格Al-Si合金铸锭的晶粒细化,一直是工业化生产的难点和研究的热点。重点综述了细化剂Ti和Si中毒、B与Sr毒化对合金晶粒细化的影响,并介绍了熔体强剪切(melt conditioned direct chill,MC)MC-DC铸造方式细化Al-Si合金晶粒组织的优点及局限性,并提出了亚共晶Al-Si合金晶粒细化的研究新思路和发展方向,以期为工业化半连续铸造亚共晶Al-Si合金的生产提供参考和借鉴。
文摘本文中应用全部PECVD工艺沉积a-SiOx:H、a-SiNx:H,和a-SiOx:H/a-SiNx:H叠层系统,比较了不同钝化膜对多晶硅太阳能电池发射极和背面钝化效果,应用FGA、RTP等热处理方法对钝化膜进行处理,重点讨论了FGA(Forming gas annealing)温度和时间的长短对钝化的影响。结果表明:低温FGA对只有单面钝化膜的硅片钝化效果不明显,而在800℃下FGA有明显作用,而且钝化效果随着时间的增加呈现出先增大后减小然后再增大的现象;退火后降温环境中是否有H和降温时间对钝化效果有很大的影响,但是对于双面膜无论FGA温度高低对钝化都有帮助,文中对上述现象做了合理的解释。最后利用双面叠层钝化膜经过FGA处理后得到的多晶硅片的少子寿命达到14.2μs,比镀膜之前的3.0μs提高了11.2μs,使多晶硅太阳能电池暗电压Voc达到630mV。
文摘Modern nuclear power plants, both newly designed generation 3 and existing generation 2 reactors, make use of passive safety systems for significant and measurable improvements in safety and reliability. Medium Pressure Safety Injection System (MP-SIS) in Tianwan Nuclear Power Plant is a typical and very important nuclear safety passive system. This paper discusses the reliability of MP-SIS on the basis of Fault Tree Analysis (FTA) with unavailability and Minimal Cut Set (MCS) calculated as two important indicators. The result illustrates that the passive MP-Safety Injection Tank barely contributes to the system’s unavailability and human interactions with Manual Valves and Motor Operated Valves have great negative impact on the reliability.
基金supported by the National Basic Research Program of China("973" Project) (Grant No. 2009CB939703)the National Natural Science Foundation of China (Grant Nos. 11104319,51172268)the Chinese Academy of Solar Energy Action Plan and by Beijing Science and Technology Project (Grant No. Y2BK024001)
文摘The ultra-small textured surface of multicrystalline silicon solar cell,prepared by electroless chemical-etching method,shows an excellent anti-reflection property over a wide spectral bandwidth.A novel back surface protection method and front surface passivation method have been used in the multicrystalline solar cells with ultra-small textured surfaces.With these improvements,the back surface remains intact after the etch process and the efficient minority lifetime is apparently increased.The test result shows that the solar cell with ultra-small textured surface can obtain better electrical performances by these improvements.
