CN106611799B - A kind of two-sided crystal silicon solar energy battery of inkjet printing and preparation method thereof - Google Patents

Abstract

The invention discloses an ink-jet printing double-sided crystalline silicon solar cell, which comprises a P-type silicon substrate. The front of the P-type silicon substrate is provided with a phosphorus diffusion layer, a suede texture, an anti-reflection passivation film, a front silver electrode, and a back surface. It is provided with a nano-silicon oxide layer, an amorphous or polycrystalline P ⁺ layer, a transparent conductive film layer, and a silver electrode on the back; it can effectively improve light absorption and current collection, and reduce optical and electrical losses. The invention also discloses a preparation method of inkjet printing double-sided crystalline silicon solar cells, which uses inkjet printing technology to form all black by adding nano-silicon oxide layer, amorphous or polycrystalline P ⁺ layer, and transparent conductive film layer solar cells, thereby effectively improving light absorption and current collection, reducing optical and electrical losses.

Description

A kind of inkjet printing double-sided crystalline silicon solar cell and its preparation method

technical field

The invention relates to the technical field of manufacturing crystalline silicon solar cells, in particular to an inkjet printing double-sided crystalline silicon solar cell and a preparation method thereof.

Background technique

With the improvement of solar cell technology, its industrial production is gradually developing towards high efficiency and low cost. However, the two main factors restricting the efficiency of solar cells are optical loss and electrical loss.

In the prior art, high-efficiency back passivation solar cells are representative of the combination of back passivation and local heavy doping technology in the metallization region, and its advantages lie in:

1) Excellent back reflector: Due to the existence of the dielectric film on the back of the battery, the internal back reflection is increased from 65% of the conventional all-aluminum back field to 92-95%, which increases the absorption of long-wave light on the one hand, and on the other hand The development of thin-film batteries in the future provides a technical guarantee;

2) Superior backside passivation technology of the dielectric film: due to the good passivation effect of the backside dielectric film, the backside recombination rate of the dielectric film area is reduced to 10-50cm/s.

The above-mentioned high-efficiency back passivation solar cell structure was proposed by the University of New South Wales in Australia as early as the 1990s, and obtained a world record of 25% crystalline silicon solar cells. However, due to its point-contact design on the back, the series resistance of the battery increases and the electrical loss increases, which is not conducive to light absorption and current collection.

Contents of the invention

One of the objectives of the present invention is to propose an inkjet printed double-sided crystalline silicon solar cell, which can effectively improve light absorption and current collection, and reduce optical and electrical losses.

The second object of the present invention is to propose a preparation method for inkjet printing double-sided crystalline silicon solar cells, which uses inkjet printing technology to form a completely black solar cell, thereby effectively improving light absorption and current collection, and reducing optical and electrical losses .

For reaching this purpose, the present invention adopts following technical scheme:

In one aspect, the present invention provides an inkjet printed double-sided crystalline silicon solar cell, comprising a P-type silicon substrate, a phosphorus diffusion layer is provided on the front of the P-type silicon substrate, and a suede fabric is provided on the front of the phosphorus diffusion layer. structure, the front of the suede texture is provided with an anti-reflection passivation film, and the front of the anti-reflection passivation film is provided with a front silver electrode; the back of the P-type silicon substrate is provided with a nano-silicon oxide layer, and the An amorphous or polycrystalline P ^{+ layer is provided on the back of the nano-silicon oxide layer, a transparent conductive film layer is provided on the back of the amorphous or polycrystalline P+ layer} , and a back silver electrode is provided on the back of the transparent conductive film layer.

In this inkjet printing double-sided crystalline silicon solar cell, a nano-silicon oxide layer, an amorphous or polycrystalline P ⁺ layer, and a transparent conductive film layer are arranged on the back of the P-type silicon substrate, wherein the nano-silicon oxide layer can provide the solar cell on the back of the cell. High-quality passivation, amorphous or polycrystalline P ⁺ layer can be used to form a tunnel structure, combined with a transparent conductive thin film layer, can significantly improve the quality of the battery back passivation and current conduction performance, reduce the rear recombination loss and current conduction loss ; Further, with the texture of the front surface of the P-type silicon substrate, the light absorption and current collection of the battery are increased, the optical and electrical losses are reduced, and the conversion efficiency of the crystalline silicon solar cell is improved.

Preferably, the p-type silicon substrate is a p-type silicon wafer, and its resistivity is 0.5-6Ω·cm; for example, 0.5Ω·cm, 0.8Ω·cm, 1.0Ω·cm, 1.3Ω·cm, 1.5Ω·cm cm, 1.9Ω·cm, 2.0Ω·cm, 2.2Ω·cm, 2.6Ω·cm, 2.8Ω·cm, 3.0Ω·cm, 3.5Ω·cm, 3.7Ω·cm, 4.0Ω·cm, 4.1Ω·cm cm, 4.4Ω·cm, 4.9Ω·cm, 5.0Ω·cm, 5.6Ω·cm or 6.0Ω·cm, etc.

Preferably, the antireflection passivation film is a SiNx passivation film or a SiO ₂ /SiNx stacked passivation film.

Preferably, the thickness of the nano-silicon oxide layer is 0.3-5nm; for example, 0.3nm, 0.35nm, 0.5nm, 0.8nm, 1.0nm, 1.1nm, 1.3nm, 1.6nm, 1.9nm, 2.0nm, 2.2nm , 2.4nm, 2.7nm, 3.0nm, 3.3nm, 3.5nm, 3.9nm, 4.0nm, 4.6nm, 4.7nm or 5.0nm, etc.

Preferably, the thickness of the amorphous or polycrystalline p+ layer is 10-1000nm, and the doping concentration is 10 ¹⁷ -10 ²² cm ^-3 ; for example, the thickness is 10nm, 13nm, 17nm, 20nm, 25nm, 30nm, 36nm, 40nm . , 340nm, 400nm, 416nm, 482nm, 500nm, 538nm, 597nm, 600nm, 636nm, 684nm, 700nm, 756nm, 800nm, 837nm, 900nm, 901nm, 957nm, 968nm, 978nm or 1000nm, etc., for example, the doping concentration is 10 ¹⁷ cm ^-3 , 10 ¹⁸ cm ^-3 , 10 ¹⁹ cm ^-3 , 10 ²⁰ cm ^-3 , 10 ²¹ cm ^-3 or 10 ²² cm ^-3 , etc.

Preferably, the thickness of the transparent conductive film layer is 10-500nm; for example, 10nm, 13nm, 15nm, 19nm, 25nm, 30nm, 34nm, 36nm, 40nm, 49nm, 65nm, 71nm, 75nm, 83nm, 90nm, 100nm, 103nm, 106nm, 109nm, 110nm, 126nm, 137nm, 142nm, 168nm, 179nm, 198nm, 200nm, 215nm, 236nm, 249nm, 268nm, 300nm, 306nm, 325nm, 378nm, 395nm, 400nm, 411nm, 456nm, 468nm, 479nm, 480nm, 485nm, 498nm or 500nm etc.

On the other hand, the present invention also provides a method for preparing an inkjet printed double-sided crystalline silicon solar cell, comprising the following steps:

1) removing the damaged layer on the surface of the P-type silicon substrate and making texture;

2) The surface of the product obtained in step 1) is etched to form an all-black concave-convex surface structure, and a suede finish is carried out to form a suede texture;

3) performing phosphorus diffusion on the surface of the product obtained in step 2) to form a phosphorus diffusion layer;

4) The edge of the product obtained in step 3) is etched, and the back side is subjected to dejunction and PSG removal;

5) Depositing an anti-reflection passivation film on the front of the product obtained in step 4) to form an anti-reflection passivation film;

6) Carry out nano-silicon oxide growth on the back side of the product obtained in step 5), forming a nano-silicon oxide layer;

7) Boron-doped amorphous or polysilicon deposition is carried out on the back side of the product obtained in step 6) to form an amorphous or polycrystalline P ⁺ layer;

8) The back side of the product obtained in step 7) is deposited with a transparent conductive film to form a transparent conductive film layer;

9) The front of the product obtained in step 8) adopts an inkjet printing method to form a front silver electrode;

10) The back of the product obtained in step 9) is ink-jet printed to form a silver electrode on the back.

Preferably, in step 1), the texturing is specifically: adopting a tank type hot alkali method, that is, alkali texturing.

Preferably, in step 2), the etching specifically includes: adopting SF ₆ gas reactive ion etching, laser etching or metal ion catalytic reaction.

Among them, in Reactive Ion Etching (RIE for short), the reactive gas (such as CF ₄ ) is excited and decomposed in RF or DC electric field to generate active particles (such as free F atoms), and the active particles react with the corroded material , to generate volatile substances, and then use the aspirator to remove the volatile substances from the reaction chamber. The commonly used reaction gases in RIE are SF ₆ , CHF ₃ , CCl ₄ and so on.

SF ₆ is sulfur hexafluoride, which has a history of one hundred years. It is an artificial inert gas synthesized by two French chemists, Moissan and Lebeau in 1900. The corrosion of SF ₆ to silicon is mainly caused by the free F radicals generated by the decomposition of SF ₆ . The volatilization of volatile substances produced by etching silicon will take silicon away, and the main function is SiF ₄ . The plasma silicon etch reaction of fluorine proceeds spontaneously and does not require ion bombardment. Therefore, the free fluorine radicals produce a high corrosion rate, but due to the spontaneous corrosion, the corrosion profile is approximately isotropic.

Preferably, in step 2), the suede modification specifically includes: cleaning with an alkaline solution.

Preferably, in step 4), the etching, dejunction and PSG (phosphosilicate glass) removal specifically include: adopting an online water rinsing method.

Among them, the online water rinsing method is: the silicon wafer is driven by rollers to make the silicon wafer float on the surface of the corrosive solution, so that only the back and edge of the silicon wafer can contact and react with the solution to achieve etching.

Preferably, in step 6), the growth of nano-silicon oxide specifically includes: wet oxidation, ozone oxidation, thermal oxidation, atomic layer deposition growth or low-pressure chemical vapor deposition.

Among them, nano-silicon oxide growth refers to the growth of a silicon oxide film layer with a thickness of nanometer (0-100 nm) on the surface of a silicon wafer;

Preferably, in step 7), the boron-doped amorphous or polysilicon deposition specifically includes: adopting a low-pressure chemical vapor deposition method.

Among them, the amorphous or polycrystalline P ⁺ layer means that the crystal form of the layer can be amorphous or polycrystalline, and both doped amorphous silicon and polycrystalline silicon layers can form excellent PP ⁺ high-low junctions with the silicon substrate. The back field is just that after the deposition of the amorphous silicon layer, the subsequent steps cannot have a high-temperature process higher than 300 degrees, while the polysilicon layer can withstand high-temperature processes without affecting performance.

Preferably, in step 8), the deposition of the transparent conductive film is specifically: using magnetron sputtering.

Wherein, the transparent conductive film is ITO (tin-doped indium trioxide) or AZO (aluminum-doped zinc oxide).

In this preparation method, a nano-silicon oxide layer is formed by growing nano-silicon oxide on the back of the P-type silicon substrate, and boron is doped on the back of the nano-silicon oxide layer to deposit amorphous or polycrystalline silicon to form an amorphous or polycrystalline P ⁺ layer. The back of the amorphous or polycrystalline P ⁺ layer is deposited with a transparent conductive film to form a transparent conductive film layer, and the use of a nano-silicon oxide layer can provide high-quality passivation on the back of the battery, and the amorphous or polycrystalline P ⁺ layer can be used to form The tunneling structure, combined with the transparent conductive film layer, can significantly improve the quality of the battery’s back passivation and current derivation performance, and reduce the backside recombination loss and current derivation loss; further, the surface of the P-type silicon substrate is etched to form a completely black Concave-convex surface structure, and then use inkjet printing technology to prepare front silver electrodes and back silver electrodes, which can increase the light absorption and current collection of the battery, reduce optical and electrical losses, and improve the conversion efficiency of crystalline silicon solar cells.

Description of drawings

Fig. 1 is a schematic structural view of an inkjet printed double-sided crystalline silicon solar cell of the present invention.

In the figure: 1-front silver electrode; 2-anti-reflection passivation film; 3-texture texture; 4-phosphorus diffusion layer; 5-P-type silicon substrate; 6-nanometer silicon oxide layer; 7-amorphous or poly crystal p+ layer; 8-transparent conductive film layer; 9-back silver electrode.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods.

Example 1

As shown in Figure 1, an inkjet printing double-sided crystalline silicon solar cell includes a P-type silicon substrate 5, a phosphorus diffusion layer 4 is arranged on the front side of the P-type silicon substrate 5, and a phosphorus diffusion layer 4 is arranged on the front side of the phosphorus diffusion layer 4. There is a suede texture 3, the front of the suede texture 3 is provided with an anti-reflection passivation film 2, and the front of the anti-reflection passivation film 2 is provided with a front silver electrode 1; the P-type silicon substrate 5 A nano-silicon oxide layer 6 is arranged on the back, an amorphous or polycrystalline P ^{+ layer 7 is arranged on the back of the nano-silicon oxide layer 6, and a transparent conductive film layer 8 is arranged on the back of the amorphous or polycrystalline P+ layer} 7 , the back side of the transparent conductive film layer 8 is provided with a back side silver electrode 9 .

A preparation method for inkjet printing double-sided crystalline silicon solar cells, comprising the following steps:

1) Removing the damaged layer on the surface of the P-type silicon substrate 5 and making texturing; wherein, in step 1), the texturing specifically includes: adopting a tank-type hot alkali method.

Specifically, a 156 mm P-type single crystal silicon wafer is selected as the P-type silicon substrate 5, and its resistivity is 1Ω·cm.

After removing damage to the P-type silicon substrate 5, chemically etch the surface of the P-type silicon substrate 5 with a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 75° C. to prepare a pyramid-shaped velvet. surface, followed by cleaning with 1% hydrofluoric acid to remove impurities.

2) Etching the surface of the product obtained in step 1) to form an all-black concave-convex surface structure, and performing suede modification to form a suede texture 3;

Wherein, in step 2), the etching is specifically: adopting SF ₆ gas, utilizing reactive ion etching; specifically, adopting the method of reactive ion etching, using SF ₆ gas to form plasma and react with the surface of the silicon wafer, A nano-scale suede texture 3 is formed on the existing suede surface, and the surface of the suede texture 3 has an uneven structure, so that the surface will appear completely black when light is reflected.

Wherein, the suede modification specifically includes: cleaning with an alkaline solution; specifically, using a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 25°C to clean the surface of the P-type silicon substrate 5 Chemical etching, modifying the surface porous silicon structure, reducing surface defects.

3) performing phosphorus diffusion on the surface of the product obtained in step 2) to form a phosphorus diffusion layer 4;

Specifically, through the tube-type high-temperature thermal diffusion method, _POCl3 is used to diffuse phosphorus on the front side of the silicon wafer to form an N-type layer with a square resistance of 95Ω/sq;

Among them, POCl ₃ is phosphorus oxychloride, which is an industrial chemical raw material. It is a colorless, transparent liquid with a pungent odor. It fumes violently in humid air and is hydrolyzed into phosphoric acid and hydrogen chloride, which further produces HP ₂ O ₄ Cl ₃ .

4) The edge of the product obtained in step 3) is etched, and the back side is subjected to dejunction and PSG removal;

Wherein, in step 4), the etching, knot removal and PSG removal are specifically: adopting an online water rinsing method. Specifically, the backside phosphosilicate glass (PSG) is removed by wet in-line equipment (that is, on-line roller equipment) (although phosphorus is diffused only on the front side of the silicon wafer to form phosphosilicate glass, but the phosphosilicate glass will penetrate into the silicon The back of the sheet) to achieve back polishing, and then remove the front phosphosilicate glass, and then use a hydrofluoric acid solution with a mass concentration of 5% to clean it.

5) Depositing an anti-reflection passivation film 2 on the front of the product obtained in step 4), forming an anti-reflection passivation film 2; wherein, the anti-reflection passivation film 2 is a SiNx passivation film;

Specifically, a silicon nitride anti-reflection film is grown on the front surface of the P-type silicon substrate 5 by PECVD (Plasma Chemical Vapor Deposition), and the thickness of the passivation anti-reflection film is 80 nm.

6) Nano-silicon oxide growth is performed on the back of the product obtained in step 5) to form a nano-silicon oxide layer 6; wherein, in step 6), the growth of nano-silicon oxide is specifically: adopting a wet oxidation method. Specifically, the thickness of the nano-silicon oxide layer 6 is 1.2 nm.

7) Boron-doped amorphous or polycrystalline silicon is deposited on the back of the product obtained in step 6) to form an amorphous or polycrystalline P ⁺ layer 7; wherein, in step 6), the boron-doped amorphous or polycrystalline silicon is deposited Specifically: low-pressure chemical vapor deposition (LPCVD) is adopted; preferably, the crystal form of the amorphous or polycrystalline p ⁺ layer 7 is polycrystalline, and the thickness of the amorphous or polycrystalline p+ layer 7 is 40nm, doped The concentration is 3×10 ²⁰ cm ^-3 .

8) The back side of the product obtained in step 7) is deposited with a transparent conductive film to form a transparent conductive film layer 8;

Wherein, in step 8), the deposition of the transparent conductive film is specifically: using magnetron sputtering.

Preferably, the thickness of the transparent conductive film layer 8 is 100 nm.

9) The front of the product obtained in step 8) adopts an inkjet printing method to form a front silver electrode 1;

10) The back side of the product obtained in step 9) is ink-jet printed to form the back silver electrode 9 .

Specifically, the back electrodes and fine grid lines are printed by inkjet and then dried, and then the front electrodes and fine grid lines are inkjet printed.

Finally, sintering, testing, and finally inkjet printing double-sided crystalline silicon solar cells can be formed.

In this embodiment, the battery conversion efficiency batch average efficiency reaches 22.3%, and the light attenuation, front busbar, back electrode and aluminum back field tension, and component side reliability test all meet TUV standards.

Example 2

As shown in Figure 1, an inkjet printing double-sided crystalline silicon solar cell includes a P-type silicon substrate 5, a phosphorus diffusion layer 4 is arranged on the front side of the P-type silicon substrate 5, and a phosphorus diffusion layer 4 is arranged on the front side of the phosphorus diffusion layer 4. There is a suede texture 3, the front of the suede texture 3 is provided with an anti-reflection passivation film 2, and the front of the anti-reflection passivation film 2 is provided with a front silver electrode 1; the P-type silicon substrate 5 A nano-silicon oxide layer 6 is arranged on the back, an amorphous or polycrystalline P ^{+ layer 7 is arranged on the back of the nano-silicon oxide layer 6, and a transparent conductive film layer 8 is arranged on the back of the amorphous or polycrystalline P+ layer} 7 , the back side of the transparent conductive film layer 8 is provided with a back side silver electrode 9 .

A preparation method for inkjet printing double-sided crystalline silicon solar cells, comprising the following steps:

1) Removing the damaged layer on the surface of the P-type silicon substrate 5 and making texturing; wherein, in step 1), the texturing specifically includes: adopting a tank-type hot alkali method.

Specifically, a 156 mm P-type single crystal silicon wafer is selected as the P-type silicon substrate 5, and its resistivity is 1Ω·cm.

After removing damage to the P-type silicon substrate 5, chemically etch the surface of the P-type silicon substrate 5 with a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 75° C. to prepare a pyramid-shaped velvet. surface, followed by cleaning with 1% hydrofluoric acid to remove impurities.

2) Etching the surface of the product obtained in step 1) to form an all-black concave-convex surface structure, and performing suede modification to form a suede texture 3;

Wherein, step 2) in, described etching is specifically: utilize metal ion catalytic reaction mode; Specifically, adopt the method for metal ion catalytic reaction, use silver nitrate solution to react with silicon chip surface to produce nano-silver particle, pass HF/ The HNO ₃ mixed solution is catalyzed by the nano-silver particles on the surface to form a nano-scale suede texture 3 on the suede surface. The surface of the suede texture 3 is an uneven structure, so that the surface will appear completely black when light is reflected.

Wherein, the suede modification specifically includes: cleaning with an alkaline solution; specifically, using a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 25°C to clean the surface of the P-type silicon substrate 5 Chemical etching, modifying the surface porous silicon structure, reducing surface defects.

3) performing phosphorus diffusion on the surface of the product obtained in step 2) to form a phosphorus diffusion layer 4;

Specifically, by means of tubular high-temperature thermal diffusion, _POCl3 is used to diffuse phosphorus on the front side of the silicon wafer to form an N-type layer with a square resistance of 100Ω/sq;

Among them, POCl ₃ is phosphorus oxychloride, which is an industrial chemical raw material. It is a colorless, transparent liquid with a pungent odor. It fumes violently in humid air and is hydrolyzed into phosphoric acid and hydrogen chloride, which further produces HP ₂ O ₄ Cl ₃ .

4) The edge of the product obtained in step 3) is etched, and the back side is subjected to dejunction and PSG removal;

Wherein, in step 4), the etching, knot removal and PSG removal are specifically: adopting an online water rinsing method. Specifically, the backside phosphosilicate glass (PSG) is removed by wet in-line equipment (that is, on-line roller equipment) (although phosphorus is diffused only on the front side of the silicon wafer to form phosphosilicate glass, but the phosphosilicate glass will penetrate into the silicon The back of the sheet) to achieve back polishing, and then remove the front phosphosilicate glass, and then use a hydrofluoric acid solution with a mass concentration of 5% to clean it.

5) Depositing an anti-reflection passivation film 2 on the front of the product obtained in step 4) to form an anti-reflection passivation film 2; wherein, the anti-reflection passivation film 2 is a SiO ₂ /SiNx laminated passivation film;

Specifically, a silicon nitride anti-reflection film is grown on the front surface of the P-type silicon substrate 5 by PECVD (Plasma Chemical Vapor Deposition), and the thickness of the passivation anti-reflection film is 80 nm.

6) The back side of the product obtained in step 5) is grown with nano-silicon oxide to form a nano-silicon oxide layer 6; wherein, in step 6), the growth of nano-silicon oxide is specifically: using ALD (atomic layer deposition growth) method . Specifically, the thickness of the nano-silicon oxide layer 6 is 1.3 nm.

7) Boron-doped amorphous or polycrystalline silicon is deposited on the back of the product obtained in step 6) to form an amorphous or polycrystalline P ⁺ layer 7; wherein, in step 7), the boron-doped amorphous or polycrystalline silicon is deposited Specifically, low-pressure chemical vapor deposition (LPCVD) is adopted; preferably, the crystal form of the amorphous or polycrystalline P ⁺ layer 7 is amorphous, and the thickness of the amorphous or polycrystalline P ⁺ layer 7 is 40nm, doped The impurity concentration is 10 ²⁰ cm ^-3 .

8) The back side of the product obtained in step 7) is deposited with a transparent conductive film to form a transparent conductive film layer 8;

Wherein, in step 8), the deposition of the transparent conductive film is specifically: using magnetron sputtering.

Preferably, the thickness of the transparent conductive film layer 8 is 100 nm.

9) The front of the product obtained in step 8) adopts an inkjet printing method to form a front silver electrode 1;

10) The back side of the product obtained in step 9) is ink-jet printed to form the back silver electrode 9 .

Specifically, the back electrodes and fine grid lines are printed by inkjet and then dried, and then the front electrodes and fine grid lines are inkjet printed.

Finally, sintering, testing, and finally inkjet printing double-sided crystalline silicon solar cells can be formed.

In this embodiment, the battery conversion efficiency batch average efficiency reaches 21.1%, and the light attenuation, front busbar, back electrode and aluminum back field tension, and component side reliability test all meet TUV standards.

Example 3

As shown in Figure 1, an inkjet printing double-sided crystalline silicon solar cell includes a P-type silicon substrate 5, a phosphorus diffusion layer 4 is arranged on the front side of the P-type silicon substrate 5, and a phosphorus diffusion layer 4 is arranged on the front side of the phosphorus diffusion layer 4. There is a suede texture 3, the front of the suede texture 3 is provided with an anti-reflection passivation film 2, and the front of the anti-reflection passivation film 2 is provided with a front silver electrode 1; the P-type silicon substrate 5 A nano-silicon oxide layer 6 is arranged on the back, an amorphous or polycrystalline P ^{+ layer 7 is arranged on the back of the nano-silicon oxide layer 6, and a transparent conductive film layer 8 is arranged on the back of the amorphous or polycrystalline P+ layer} 7 , the back side of the transparent conductive film layer 8 is provided with a back side silver electrode 9 .

A preparation method for inkjet printing double-sided crystalline silicon solar cells, comprising the following steps:

1) Removing the damaged layer on the surface of the P-type silicon substrate 5 and making texturing; wherein, in step 1), the texturing specifically includes: adopting a tank-type hot alkali method.

Specifically, a 156 mm P-type single crystal silicon wafer is selected as the P-type silicon substrate 5, and its resistivity is 1Ω·cm.

After removing damage to the P-type silicon substrate 5, chemically etch the surface of the P-type silicon substrate 5 with a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 75° C. to prepare a pyramid-shaped velvet. surface, followed by cleaning with 1% hydrofluoric acid to remove impurities.

2) Etching the surface of the product obtained in step 1) to form an all-black concave-convex surface structure, and performing suede modification to form a suede texture 3;

Wherein, in step 2), the etching is specifically: adopting SF ₆ gas, utilizing RIE (Reactive Ion Etching) reaction mode; specifically, adopting the method of RIE reaction, using SF ₆ gas to form plasma and silicon chip surface reaction, a nano-scale suede texture 3 is formed on the existing suede surface, and the surface of the suede texture 3 is an uneven structure, so that the surface will appear completely black when light is reflected.

Wherein, the suede modification specifically includes: cleaning with an alkaline solution; specifically, using a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 25°C to clean the surface of the P-type silicon substrate 5 Chemical etching, modifying the surface porous silicon structure, reducing surface defects.

3) performing phosphorus diffusion on the surface of the product obtained in step 2) to form a phosphorus diffusion layer 4;

Specifically, through the tubular high-temperature thermal diffusion method, _POCl3 is used to diffuse phosphorus on the front side of the silicon wafer to form an N-type layer with a square resistance of 110Ω/sq;

Among them, POCl ₃ is phosphorus oxychloride, which is an industrial chemical raw material. It is a colorless, transparent liquid with a pungent odor. It fumes violently in humid air and is hydrolyzed into phosphoric acid and hydrogen chloride, which further produces HP ₂ O ₄ Cl ₃ .

4) The edge of the product obtained in step 3) is etched, and the back side is subjected to dejunction and PSG removal;

Wherein, in step 4), the etching, knot removal and PSG removal are specifically: adopting an online water rinsing method. Specifically, the backside phosphosilicate glass (PSG) is removed by wet in-line equipment (that is, on-line roller equipment) (although phosphorus is diffused only on the front side of the silicon wafer to form phosphosilicate glass, but the phosphosilicate glass will penetrate into the silicon The back of the sheet) to achieve back polishing, and then remove the front phosphosilicate glass, and then use a hydrofluoric acid solution with a mass concentration of 5% to clean it.

5) Depositing an anti-reflection passivation film 2 on the front of the product obtained in step 4) to form an anti-reflection passivation film 2; wherein, the anti-reflection passivation film 2 is a SiO ₂ /SiNx laminated passivation film;

Specifically, a silicon nitride anti-reflection film is grown on the front surface of the P-type silicon substrate 5 by PECVD (Plasma Chemical Vapor Deposition), and the thickness of the passivation anti-reflection film is 80 nm.

6) Nano-silicon oxide growth is performed on the back of the product obtained in step 5) to form a nano-silicon oxide layer 6; wherein, in step 6), the growth of nano-silicon oxide is specifically: adopting a wet oxidation method. Specifically, the thickness of the nano-silicon oxide layer 6 is 1.2 nm.

7) Boron-doped amorphous or polycrystalline silicon is deposited on the back of the product obtained in step 6) to form an amorphous or polycrystalline P ⁺ layer 7; wherein, in step 7), the boron-doped amorphous or polycrystalline silicon is deposited Specifically, low-pressure chemical vapor deposition (LPCVD) is adopted; preferably, the crystal form of the amorphous or polycrystalline p ⁺ layer 7 is polycrystalline, and the thickness of the amorphous or polycrystalline p+ layer 7 is 50 nm, doped The concentration is 5×10 ²⁰ cm ^-3 .

8) The back side of the product obtained in step 7) is deposited with a transparent conductive film to form a transparent conductive film layer 8;

Wherein, in step 8), the deposition of the transparent conductive film is specifically: using magnetron sputtering.

Preferably, the thickness of the transparent conductive film layer 8 is 100 nm.

9) The front of the product obtained in step 8) adopts an inkjet printing method to form a front silver electrode 1;

10) The back side of the product obtained in step 9) is ink-jet printed to form the back silver electrode 9 .

Specifically, the back electrodes and fine grid lines are printed by inkjet and then dried, and then the front electrodes and fine grid lines are inkjet printed.

Finally, sintering, testing, and finally inkjet printing double-sided crystalline silicon solar cells can be formed.

In this embodiment, the battery conversion efficiency batch average efficiency reaches 21.2%, and the light attenuation, front busbar, back electrode and aluminum back field tension, and component side reliability test all meet TUV standards.

Example 4

As shown in Figure 1, an inkjet printing double-sided crystalline silicon solar cell includes a P-type silicon substrate 5, a phosphorus diffusion layer 4 is arranged on the front side of the P-type silicon substrate 5, and a phosphorus diffusion layer 4 is arranged on the front side of the phosphorus diffusion layer 4. There is a suede texture 3, the front of the suede texture 3 is provided with an anti-reflection passivation film 2, and the front of the anti-reflection passivation film 2 is provided with a front silver electrode 1; the P-type silicon substrate 5 A nano-silicon oxide layer 6 is arranged on the back, an amorphous or polycrystalline P ^{+ layer 7 is arranged on the back of the nano-silicon oxide layer 6, and a transparent conductive film layer 8 is arranged on the back of the amorphous or polycrystalline P+ layer} 7 , the back side of the transparent conductive film layer 8 is provided with a back side silver electrode 9 .

A preparation method for inkjet printing double-sided crystalline silicon solar cells, comprising the following steps:

1) Removing the damaged layer on the surface of the P-type silicon substrate 5 and making texturing; wherein, in step 1), the texturing specifically includes: adopting a tank-type hot alkali method.

Specifically, a 156 mm P-type single crystal silicon wafer is selected as the P-type silicon substrate 5, and its resistivity is 1Ω·cm.

After removing damage to the P-type silicon substrate 5, chemically etch the surface of the P-type silicon substrate 5 with a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 75° C. to prepare a pyramid-shaped velvet. surface, followed by cleaning with 1% hydrofluoric acid to remove impurities.

2) Etching the surface of the product obtained in step 1) to form an all-black concave-convex surface structure, and performing suede modification to form a suede texture 3;

Wherein, in step 2), the etching is specifically: adopting SF ₆ gas, utilizing the RIE reaction mode; specifically, adopting the method of RIE etching, using SF ₆ gas to form plasma and react with the silicon wafer surface, in the existing The suede surface forms a nano-scale suede texture 3, and the surface of the suede texture 3 has an uneven structure, so that the surface will appear completely black when light is reflected.

Wherein, the suede modification specifically includes: cleaning with an alkaline solution; specifically, using a sodium hydroxide or potassium hydroxide solution with a mass concentration fraction of 0.5% at 25°C to clean the surface of the P-type silicon substrate 5 Chemical etching, modifying the surface porous silicon structure, reducing surface defects.

3) performing phosphorus diffusion on the surface of the product obtained in step 2) to form a phosphorus diffusion layer 4;

Specifically, through the tube-type high-temperature thermal diffusion method, _POCl3 is used to diffuse phosphorus on the front side of the silicon wafer to form an N-type layer with a square resistance of 120Ω/sq;

Among them, POCl ₃ is phosphorus oxychloride, which is an industrial chemical raw material. It is a colorless, transparent liquid with a pungent odor. It fumes violently in humid air and is hydrolyzed into phosphoric acid and hydrogen chloride, which further produces HP ₂ O ₄ Cl ₃ .

4) The edge of the product obtained in step 3) is etched, and the back side is subjected to dejunction and PSG removal;

Wherein, in step 4), the etching, knot removal and PSG removal are specifically: adopting an online water rinsing method. Specifically, the backside phosphosilicate glass (PSG) is removed by wet in-line equipment (that is, on-line roller equipment) (although phosphorus is diffused only on the front side of the silicon wafer to form phosphosilicate glass, but the phosphosilicate glass will penetrate into the silicon The back of the sheet) to achieve back polishing, and then remove the front phosphosilicate glass, and then use a hydrofluoric acid solution with a mass concentration of 5% to clean it.

5) Depositing an anti-reflection passivation film 2 on the front of the product obtained in step 4) to form an anti-reflection passivation film 2; wherein, the anti-reflection passivation film 2 is a SiO ₂ /SiNx laminated passivation film;

Specifically, a silicon nitride anti-reflection film is grown on the front surface of the P-type silicon substrate 5 by PECVD (Plasma Chemical Vapor Deposition), and the thickness of the passivation anti-reflection film is 80 nm.

6) Nano-silicon oxide growth is performed on the back of the product obtained in step 5) to form a nano-silicon oxide layer 6; wherein, in step 6), the growth of nano-silicon oxide is specifically: using LPCVD deposition. Specifically, the thickness of the nano-silicon oxide layer 6 is 1.2 nm.

7) Boron-doped amorphous or polycrystalline silicon is deposited on the back of the product obtained in step 6) to form an amorphous or polycrystalline P ⁺ layer 7; wherein, in step 7), the boron-doped amorphous or polycrystalline silicon is deposited Specifically: adopt low-pressure chemical vapor deposition (LPCVD); preferably, the crystal form of the amorphous or polycrystalline P ⁺ layer 7 is 10nm amorphous and 40nm polycrystalline, and the amorphous or polycrystalline P ⁺ layer 7 The combined thickness is 50nm, and the doping concentration is 8×10 ²⁰ cm ^-3 .

8) The back side of the product obtained in step 7) is deposited with a transparent conductive film to form a transparent conductive film layer 8;

Wherein, in step 8), the deposition of the transparent conductive film is specifically: using magnetron sputtering.

Preferably, the thickness of the transparent conductive film layer 8 is 100 nm.

9) The front of the product obtained in step 8) adopts an inkjet printing method to form a front silver electrode 1;

10) The back side of the product obtained in step 9) is ink-jet printed to form the back silver electrode 9 .

Specifically, the back electrodes and fine grid lines are printed by inkjet and then dried, and then the front electrodes and fine grid lines are inkjet printed.

Finally, sintering, testing, and finally inkjet printing double-sided crystalline silicon solar cells can be formed.

In this embodiment, the battery conversion efficiency batch average efficiency reaches 22.15%, and the light attenuation, front busbar, back electrode and aluminum back field tension, and component side reliability test all meet TUV standards.

Comparative example 1

The preparation method of conventional inkjet printing double-sided crystalline silicon solar cells comprises the following steps:

1) removing the damaged layer on the surface of the P-type silicon substrate and making texture;

2) performing boron diffusion on the back surface of the product obtained in step 1) to form a boron diffusion layer;

Specifically, BBr ₃ is used to diffuse boron on the back of the silicon wafer through a tube-type high-temperature thermal diffusion method to form a P ⁺ type layer with a square resistance of 40Ω/sq;

3) the front side of the product obtained in step 2) is deknotted on one side;

Wherein, in step 3), the knot removal specifically includes: adopting an online roller cleaning method. Specifically, the front side borosilicate glass (BSG) is removed using a wet in-line device (ie, an in-line roller-type device).

5) performing phosphorous diffusion on the front side of the product obtained in step 4) to form a phosphorous doped layer;

Specifically, by means of tubular high-temperature thermal diffusion, POCl ₃ is used to diffuse phosphorus on the front side of the silicon wafer to form an N-type layer with a square resistance of 100Ω/sq.

6) the product obtained in step 5) carries out edge etching and BSG and PSG removal;

Specifically, an online water rinsing method is adopted. Specifically, wet in-line equipment (ie, in-line roller equipment) is used to remove edge knots, front-side phosphosilicate glass (PSG) and back-side borosilicate glass (BSG).

7) Silicon nitride is deposited on both sides of the product obtained in step 6), with a thickness of 80nm;

8) prepare front silver electrodes on the front of the product obtained in step 7);

9) Prepare a back silver electrode on the back of the product obtained in step 8).

Finally, sintering, testing, and finally forming a double-sided crystalline silicon solar cell.

In this preparation method, the battery conversion efficiency batch average efficiency is only 20.1%, which is obviously not as good as the battery conversion efficiency batch average efficiency of the preparation method of the present invention.

The applicant declares that the present invention illustrates the detailed methods of the present invention through the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed methods, that is, it does not mean that the present invention must rely on the above-mentioned detailed methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. A double-sided crystalline silicon solar cell for inkjet printing, comprising a P-type silicon substrate, characterized in that, the front of the P-type silicon substrate is provided with a phosphorus diffusion layer, and the front of the phosphorus diffusion layer is provided with a suede fabric structure, the front side of the suede texture is provided with an anti-reflection passivation film, and the front side of the anti-reflection passivation film is provided with a front silver electrode; A nano-silicon oxide layer is provided on the back of the P-type silicon substrate, an amorphous or polycrystalline P ^{+ layer is provided on the back of the nano-silicon oxide layer, and a transparent conductive layer is provided on the back of the amorphous or polycrystalline P+ layer} . A film layer, the back side of the transparent conductive film layer is provided with a back silver electrode. 2. The inkjet printing double-sided crystalline silicon solar cell according to claim 1, wherein the p-type silicon substrate is a p-type silicon wafer, and its resistivity is 0.5-6Ω·cm; The anti-reflection passivation film is a SiNx passivation film or a SiO ₂ /SiNx laminated passivation film. 3. The inkjet printing double-sided crystalline silicon solar cell according to claim 1, wherein the thickness of the nano-silicon oxide layer is 0.3-5nm; The thickness of the amorphous or polycrystalline P ⁺ layer is 10-1000 nm, and the doping concentration is 10 ¹⁷ -10 ²² cm ^-3 ; The thickness of the transparent conductive film layer is 10-500nm. 4. A preparation method for inkjet printing double-sided crystalline silicon solar cells according to any one of claims 1-3, characterized in that it comprises the following steps: 1) removing the damaged layer on the surface of the P-type silicon substrate and making texture; 2) The surface of the product obtained in step 1) is etched to form an all-black concave-convex surface structure, and a suede finish is carried out to form a suede texture; 3) performing phosphorus diffusion on the surface of the product obtained in step 2) to form a phosphorus diffusion layer; 4) The edge of the product obtained in step 3) is etched, and the back side is subjected to dejunction and PSG removal; 5) Depositing an anti-reflection passivation film on the front of the product obtained in step 4) to form an anti-reflection passivation film; 6) Carry out nano-silicon oxide growth on the back side of the product obtained in step 5), forming a nano-silicon oxide layer; 7) Boron-doped amorphous or polysilicon deposition is carried out on the back side of the product obtained in step 6) to form an amorphous or polycrystalline P ⁺ layer; 8) The back side of the product obtained in step 7) is deposited with a transparent conductive film to form a transparent conductive film layer; 9) The front of the product obtained in step 8) adopts an inkjet printing method to form a front silver electrode; 10) The back of the product obtained in step 9) is ink-jet printed to form a silver electrode on the back. 5. The preparation method according to claim 4, characterized in that, in step 1), the texturing is specifically: adopting a tank type hot alkali method. 6. preparation method according to claim 4, is characterized in that, step 2) in, described etching is specifically: adopt the reactive ion etching of SF ₆ gas, laser etching or metal ion catalytic reaction mode; The suede modification specifically includes: cleaning with an alkaline solution. 7. The preparation method according to claim 4, characterized in that, in step 4), the etching, deknotting and PSG removal are specifically: adopting an online water rinsing method. 8. The preparation method according to claim 4, characterized in that, in step 6), the growth of nano-silicon oxide is specifically: using wet oxidation, ozone oxidation, thermal oxidation, atomic layer deposition growth or low-pressure chemical vapor deposition Way. 9. The preparation method according to claim 4, characterized in that, in step 7), the boron-doped amorphous or polysilicon deposition specifically comprises: adopting a low-pressure chemical vapor deposition method. 10. The preparation method according to claim 4, characterized in that, in step 8), the deposition of the transparent conductive film is specifically: adopting a magnetron sputtering method.