Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province

Dalian, China

Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province

Dalian, China
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Li P.,Dalian University of Technology | Li P.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Wang K.,Dalian University of Technology | Wang K.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 6 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2017

The silicon target material was prepared by adding Al-6B master alloy in directional solidification. The microstructure was characterized and the resistivity was studied in this work. The results showed that the purity of the silicon target material was more than 99.999% (5N). The resistivity was ranges from 0.002 to 0.030 Ω•cm along the ingot height. It was revealed that the particles of AlB2 in Al-6B master alloy would react spontaneously and generate clusters of [B] and [Al] in molten silicon at 1723 K. After directional solidification, the content of B and Al were increasing gradually with the increase of solidified fraction. The measured values of B were in good agreement with the curve of the Scheil equation below 80% of the ingot height. The mean concentration of B was about 17.20 ppmw and the mean concentration of Al was about 8.07 ppmw after directional solidification. The measured values of Al were fitting well with the curve of values which the effective segregation coefficient was 0.00378. It was observed that B co-doped Al in directional solidification polysilicon could regulate resistivity mutually. This work provides the theoretical basis and technical support for industrial production of the silicon target material. © Published under licence by IOP Publishing Ltd.


Shi W.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Shi W.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Tan Y.,Dalian University of Technology | And 2 more authors.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2013

With pre-oxidized fiber integrated felt prepared by relayed needle punching process as preform and thermosetting resin as precursor, impregnation-curing-carbonization of resin-graphitization process was employed to prepare rigid carbon fiber integrated felt used for thermal insulation. Effect of every process including needle punching parameters, carbonization temperature, solution concentration and curing pressure on density was studied. Microstructure of samples was studied by using SEM. The results show that high values of needle-punching parameters lead to high values of preform density, carbonization temperature has little influence on density, but much influence on carbon content. Also solution concentration and preform density have a certain influence on density. What is more, with increasing curing pressure, the density of samples increases.


Jiang D.,Dalian University of Technology | Jiang D.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Tan Y.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 8 more authors.
Materials Letters | Year: 2012

In the current study, a new method for the removal of phosphorus in molten silicon, electron beam candle melting (EBCM), is proposed and discussed. The proposed method combines the characteristics of electron beam melting (EBM) and the high saturated vapor pressure of P in molten Si. Simulation results show the existence of three typical temperature distributions and morphologies of the molten pool that correspond to the different radii of the electron beam circular pattern at constant power. The critical molten pool with the maximum surface area and the minimum depth was determined. EBCM resulting in the critical molten pool was proven to be more effective in the removal of P in molten Si compared with EBM. In addition, the energy utilization ratio was enhanced. © 2012 Elsevier B.V. All rights reserved.


Li Y.,Dalian University of Technology | Li Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Tan Y.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 5 more authors.
Journal of Alloys and Compounds | Year: 2014

Si-Al and Si-Al-Sn alloy melts were used for silicon purification by alloy solidification refining method. The effects of Sn addition on alloy microstructure, eutectic Si morphology, as well as B distribution were investigated using optical microscopy, scanning electron microscopy, electron probe microanalyzer and inductively coupled plasma mass spectrometer. Primary Si and αAl + Si structures with flake-like eutectic Si were found in Si-Al alloy; while an additional structure of αAl + βSn + Si in Si-Al-Sn alloy was found. Si in αAl + Si eutectic had a globular shape, whereas some Si in αAl + βSn + Si eutectic had an octahedral shape. Compared with primary Si, more boron was found to distribute in final solidified phase during the solidification, i.e. αAl + Si for Si-Al system and αAl + βSn + Si for Si-Al-Sn system. The refining ratio of B decreased with increasing Al content in Si-Al alloy melt, while increased with Sn addition using Si-Al-Sn alloy melt. © 2013 Elsevier B.V. All rights reserved.


Li J.,Dalian University of Technology | Li J.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Liu Y.,Dalian University of Technology | Liu Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 10 more authors.
Journal of Crystal Growth | Year: 2013

Silicon (Si) waste and use of large amount of acid restrict the application of metallurgical grade silicon purification by Si-Al alloying process. To increase the recovery rate of primary Si, the effects of metal tin (Sn) addition on the recovery rate of primary Si were investigated in 31.86 at% Si-Al alloy. The actual recovery rate of primary Si is about 83% in Si-Al-Sn alloy with 10 at% Sn addition, which is higher than that of the 31.86 at% Si-Al alloy (62%). Sn addition tends to produce primary Si dendrites with larger widths. With the agglomeration of primary Si by Lorenz force considered, Sn addition is significant not only for resource recycling but also for environmental protection because of the reduced amount of acid used in the process. The impurities in primary Si and the impurity distribution in alloys were analyzed by inductively coupled plasma-mass spectrometry and electron probe microanalysis, respectively. Results show that Sn addition was favorable for the collection of boron in the Si-Al-Sn phase. © 2013 Elsevier B.V. All rights reserved.


Ye F.,Dalian University of Technology | Xu F.F.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province
Materials Research Innovations | Year: 2015

Boron and oxygen are major non-metallic impurities in silicon, and they often exist in the form of boron and oxygen (B-O) pair, which plays an important role in silicon and can induce the silicon-based solar cell suffering a light-induced-degradation in efficiency up to 1-2%. In this work, the ab initio calculations based on the density functional theory (DFT) are carried out to understand the effect of silicon environment on B-O bonding state by comparing the states in vacuum, oxide, and silicon. It has been found out that the contribution of 2s and 2p orbitals of oxygen to the bonding state is always higher than those of the boron. Moreover, because the B-O spacing in silicon is larger, the electronic density of states (DOS) B and O are decreased by the bonding with the silicon atoms, and the bonding strength of B-O pair in silicon is lower than those in boron oxide and vacuum. The decrease in the DOS and the bonding strength is also supported by the fact that the atomic population is also decreased by the silicon environment. © W. S. Maney & Son Ltd 2015.


Sun S.H.,Dalian University of Technology | Sun S.H.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Tan Y.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 5 more authors.
Journal of Materials Engineering and Performance | Year: 2012

The effects of impurities on the resistivity distribution and polarity of multicrystalline silicon ingot prepared by directional solidification were investigated in this article. The shape of the equivalence line of the resistivity in the vertical and cross sections was determined by the solid-liquid interface. Along the solidification height of silicon ingot, the conductive type changed from p-type in the lower part of the silicon ingot to n-type in the upper part of the silicon ingot. The resistivity in the vertical section of the silicon ingot initially increased along the height of the solidified part, and reached its maximum at the polarity transition position, then decreased rapidly along the height of solidified part and approached zero on the top of the ingot because of the accumulation of impurities. The variation of resistivity in the vertical section of the ingot has been proven to be deeply relevant to the distribution of Al, B, and P in the growth direction of solidification. © 2011 ASM International.


Jiang D.,Dalian University of Technology | Jiang D.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Shi S.,Dalian University of Technology | Shi S.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 6 more authors.
Vacuum | Year: 2013

The purification of metallurgical grade silicon, especially the removal of aluminum, was investigated by electron beam melting and solidification. Small amounts of silicon raw materials were melted in an electron beam furnace with same melting time and different solidification time to obtain the distribution of Al in silicon ingot. The removal mechanisms in different stages were also discussed. The results show that the removal of Al during melting process only depends on evaporation and that during solidification process depends on both segregation and evaporation. The distribution of Al shows an obvious increasing trend from the bottom to the top of the silicon ingot when solidification time is 600 s. The removal efficiency in most area is close to that in the ingot solidified instantaneously, but the energy consumption is less, which is considered to be an effective way for the purification of silicon. © 2013 Elsevier Ltd. All rights reserved.


Tan Y.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Guo X.,Dalian University of Technology | Guo X.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 6 more authors.
Vacuum | Year: 2013

According to the traditional metallurgical theory, the evaporation process of phosphorus and silicon during silicon refining by electron beam melting (EBM) is discussed and a theoretical model is established to obtain the loss rate of silicon, the removal efficiency of phosphorus and the corresponding energy consumption. The results show that phosphorus can be removed from silicon melt efficiently and quickly by EBM. There is a one-to-one correspondence between the loss of silicon and the removal efficiency of phosphorus, indicating that they have obvious effect on each other, whereas the EB power has little influence on the loss rate of silicon. If the EB power is increased from 9 kW to 21 kW, the melting time can be shortened by 68%, the loss of silicon increased by only 0.1% and the energy consumption decreased by 25%. Based on the theoretical and experimental results, a high-power EBM method is considered to be a better way for the removal of phosphorus with high efficiency and low energy consumption under such experiment conditions. © 2013 Elsevier Ltd. All rights reserved.


Wang H.Y.,Dalian University of Technology | Wang H.Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | Tan Y.,Dalian University of Technology | Tan Y.,Key Laboratory for Solar Energy Photovoltaic System of Liaoning Province | And 6 more authors.
Separation and Purification Technology | Year: 2012

A novel method to separate silicon and silicon carbide from kerf loss slurry by Al-Si alloying process has been reported in this paper. The kerf loss slurry was washed and dried, and then aluminum was added on the top of these dry powders with silicon and silicon carbide. The Al-Si alloying process was performed in argon atmosphere using a vacuum carbon tube furnace at 1773 K. In this way, an Al-Si ingot was obtained, on the surface of which a lot of hexagonal crystals were observed. The Al-Si ingot was characterized by X-ray diffraction, scanning electron microscopy, X-ray fluorescence and electron probe micro-analyzer. The X-ray results indicated that the Al 4C 3 phase was obtained on the top of the cast. The scanning electron microscopy, X-ray diffraction and electron probe micro-analyzer results revealed that the Al-Si alloy without silicon carbide phase formed in the cast, which indicated that silicon and silicon carbide can be separated from slurry by this alloying process. © 2012 Published by Elsevier B.V. All rights reserved.

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