Method for absorbing impurity B in silicon by using oxygen-containing porous layer

A technology of porous layer and porous silicon, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of unsatisfactory removal, large segregation coefficient, difficult separation, etc., and achieve novel preparation route, simple process, and easy The effect of the operation

Pending Publication Date: 2019-10-25
GUIZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because B has a large segregation coefficient in silicon, which is close to 1, it is difficult to separate from the silicon matrix during the solidification process, and the removal is not ideal.

Method used

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  • Method for absorbing impurity B in silicon by using oxygen-containing porous layer

Examples

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Effect test

Embodiment 1

[0022] Example 1. A method for absorbing impurity B in silicon by using an oxygen-containing porous layer, carried out according to the following steps:

[0023] a) Crushing of silicon block: make silicon block into 120-mesh metallurgical-grade silicon powder; the specific preparation is: first crush metallurgical-grade silicon to millimeter-sized particles, then use a planetary ball mill for 120 minutes, and filter through a 120-mesh sieve;

[0024] Afterwards, silicon powder pretreatment: use 2mol / L H 2 SO 4 and H 2 o 2 The mixed solution, 2mol / L HF solution, absolute ethanol and pure water were stirred and washed with a magnetic stirrer for 25 min, filtered, and dried in a vacuum oven;

[0025] b) Preparation of porous silicon: Corrode the pretreated silicon powder with corrosion solution at high temperature: put 10g of silicon powder into a plastic beaker, pour 5mol / L HF, 0.03mol / L Fe(NO 3 ) 3 The mixed solution was kept in an agitated water bath at 80°C for 120 minu...

Embodiment 2

[0030] Example 2. A method for absorbing impurity B in silicon by using an oxygen-containing porous layer, carried out according to the following steps:

[0031] a) Crushing of silicon block: make silicon block into 120-mesh metallurgical-grade silicon powder; the specific preparation is: first crush metallurgical-grade silicon to millimeter-sized particles, then use a planetary ball mill for 120 minutes, and filter through a 120-mesh sieve;

[0032] Afterwards, silicon powder pretreatment: use 2mol / L H 2 SO 4 and H 2 o 2 The mixed solution, 2mol / L HF solution, absolute ethanol and pure water were stirred and washed with a magnetic stirrer for 25 min, filtered, and dried in a vacuum oven;

[0033] b) Preparation of porous silicon: Corrode the pretreated silicon powder with corrosion solution at high temperature: put 10g into the liner of the hydrothermal kettle, pour 5mol / L HF, 0.03mol / L Fe(NO 3 ) 3 The mixed solution was kept in a 150°C hydrothermal kettle for 300min; ...

Embodiment 3

[0038] Example 3. A method for absorbing impurity B in silicon by using an oxygen-containing porous layer, carried out according to the following steps:

[0039] a) Crushing of silicon block: make silicon block into 120-mesh metallurgical-grade silicon powder; the specific preparation is: first crush metallurgical-grade silicon to millimeter-sized particles, then use a planetary ball mill for 120 minutes, and filter through a 120-mesh sieve;

[0040] Afterwards, silicon powder pretreatment: use 2mol / L H 2 SO 4 and H 2 o 2 The mixed solution, 2mol / L HF solution, absolute ethanol and pure water were stirred and washed with a magnetic stirrer for 25 min, filtered, and dried in a vacuum oven;

[0041] b) Preparation of porous silicon: Corrode the pretreated silicon powder with corrosion solution at high temperature: put 10g into the liner of the hydrothermal kettle, pour 5mol / L HF, 0.03mol / L Fe(NO 3 ) 3The mixed solution was kept in a 150°C hydrothermal kettle for 300min;

...

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PUM

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Abstract

The invention discloses a method for absorbing an impurity B in silicon by using an oxygen-containing porous layer. The method includes the following steps that: (a), a silicon block is prepared into50-1000-mesh silicon powder; then the silicon powder is pretreated, specifically, the silicon powder is stirred and cleaned by using a mixed solution of H2SO4 and H2O2, a HF solution, an anhydrous ethanol solution and pure water correspondingly, and then put into a vacuum drying oven for drying; (b) the pretreated silicon powder is subjected to high temperature corrosion with a corrosion solution,and then cleaning is performed with pure water, filtering and drying are performed, and porous silicon is obtained; (c), the porous silicon is oxidized, specifically, the porous silicon is oxidized by means of aqueous solution immersion or high-temperature annealing, and an oxygen-containing porous layer is constructed on the surface of the porous silicon, and oxygen-containing porous silicon isobtained; and (d), the oxygen-containing porous silicon is pickled, the surface oxygen-containing layer is removed, and silicon powder with removal of B is obtained after cleaning, filtering and drying are performed. The method is novel in preparation path, simple in process, easy to operate and low in cost, the concentration of B can be effectively reduced in metallurgical grade silicon, and theconcentration of the B can be easily controlled in the process.

Description

technical field [0001] The invention relates to the technical field of impurity removal for silicon materials, in particular to a method for absorbing impurity B in silicon by using an oxygen-containing porous layer. Background technique [0002] Silicon-based solar cells are essentially semiconductor materials. Among many solar cells, the technology of silicon-based solar cells is undoubtedly the most mature. Silicon-based solar cells have the advantages of high photoelectric conversion efficiency, long life, convenient use, and abundant raw materials. Therefore, silicon solar cells have great potential in the development of solar cells in the future. [0003] The silicon from which solar cells are made is generally believed to need to be purer than 6N. At present, metallurgical methods have achieved good removal effects on metal impurities Fe, Al, Ca, etc. and non-metal impurities C, O, etc. However, because B has a large segregation coefficient in silicon, which is clo...

Claims

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Application Information

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IPC IPC(8): C01B33/037
CPCC01B33/037
Inventor 麦毅侯高蕾吴复忠戴新义李水娥谷肄静陈敬波
Owner GUIZHOU UNIV
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