CN117712223A - Solar cell intermediate and preparation method and application thereof - Google Patents
Solar cell intermediate and preparation method and application thereof Download PDFInfo
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- CN117712223A CN117712223A CN202311677075.9A CN202311677075A CN117712223A CN 117712223 A CN117712223 A CN 117712223A CN 202311677075 A CN202311677075 A CN 202311677075A CN 117712223 A CN117712223 A CN 117712223A
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- boron
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- oxide
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- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical group [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 139
- 229910052796 boron Inorganic materials 0.000 claims abstract description 128
- 229910052751 metal Inorganic materials 0.000 claims abstract description 71
- 239000002184 metal Substances 0.000 claims abstract description 71
- 239000002002 slurry Substances 0.000 claims abstract description 62
- 238000000034 method Methods 0.000 claims abstract description 58
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 52
- 239000010703 silicon Substances 0.000 claims abstract description 52
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 49
- 239000000758 substrate Substances 0.000 claims abstract description 45
- 238000002161 passivation Methods 0.000 claims abstract description 19
- 238000009792 diffusion process Methods 0.000 claims description 38
- 239000011521 glass Substances 0.000 claims description 36
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 33
- 239000000843 powder Substances 0.000 claims description 30
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 24
- -1 alcohol ester Chemical class 0.000 claims description 24
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 24
- 229910052760 oxygen Inorganic materials 0.000 claims description 24
- 239000001301 oxygen Substances 0.000 claims description 24
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- 238000000151 deposition Methods 0.000 claims description 20
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 19
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- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 claims description 18
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 18
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 18
- 239000003513 alkali Substances 0.000 claims description 17
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 15
- 239000005388 borosilicate glass Substances 0.000 claims description 15
- 238000005245 sintering Methods 0.000 claims description 14
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- 239000001856 Ethyl cellulose Substances 0.000 claims description 12
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 claims description 12
- 239000004698 Polyethylene Substances 0.000 claims description 12
- 229910000416 bismuth oxide Inorganic materials 0.000 claims description 12
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 12
- 239000000292 calcium oxide Substances 0.000 claims description 12
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 12
- TYIXMATWDRGMPF-UHFFFAOYSA-N dibismuth;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Bi+3].[Bi+3] TYIXMATWDRGMPF-UHFFFAOYSA-N 0.000 claims description 12
- 239000003822 epoxy resin Substances 0.000 claims description 12
- 229920001249 ethyl cellulose Polymers 0.000 claims description 12
- 235000019325 ethyl cellulose Nutrition 0.000 claims description 12
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 12
- 229910000464 lead oxide Inorganic materials 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 12
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 claims description 12
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims description 12
- 229920000647 polyepoxide Polymers 0.000 claims description 12
- 229920000573 polyethylene Polymers 0.000 claims description 12
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 229910000420 cerium oxide Inorganic materials 0.000 claims description 11
- 238000001035 drying Methods 0.000 claims description 11
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 claims description 11
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 10
- 239000004793 Polystyrene Substances 0.000 claims description 10
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 10
- 150000001639 boron compounds Chemical class 0.000 claims description 10
- 229920002223 polystyrene Polymers 0.000 claims description 10
- 238000007639 printing Methods 0.000 claims description 10
- 229910052714 tellurium Inorganic materials 0.000 claims description 10
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 claims description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 9
- FAQYAMRNWDIXMY-UHFFFAOYSA-N trichloroborane Chemical compound ClB(Cl)Cl FAQYAMRNWDIXMY-UHFFFAOYSA-N 0.000 claims description 9
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 7
- OAYXUHPQHDHDDZ-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethanol Chemical compound CCCCOCCOCCO OAYXUHPQHDHDDZ-UHFFFAOYSA-N 0.000 claims description 6
- WAEVWDZKMBQDEJ-UHFFFAOYSA-N 2-[2-(2-methoxypropoxy)propoxy]propan-1-ol Chemical compound COC(C)COC(C)COC(C)CO WAEVWDZKMBQDEJ-UHFFFAOYSA-N 0.000 claims description 6
- 239000004925 Acrylic resin Substances 0.000 claims description 6
- 229920000178 Acrylic resin Polymers 0.000 claims description 6
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 claims description 6
- 239000004354 Hydroxyethyl cellulose Substances 0.000 claims description 6
- 229920002153 Hydroxypropyl cellulose Polymers 0.000 claims description 6
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 claims description 6
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 6
- 239000004359 castor oil Substances 0.000 claims description 6
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- 238000011049 filling Methods 0.000 claims description 6
- ZEMPKEQAKRGZGQ-XOQCFJPHSA-N glycerol triricinoleate Natural products CCCCCC[C@@H](O)CC=CCCCCCCCC(=O)OC[C@@H](COC(=O)CCCCCCCC=CC[C@@H](O)CCCCCC)OC(=O)CCCCCCCC=CC[C@H](O)CCCCCC ZEMPKEQAKRGZGQ-XOQCFJPHSA-N 0.000 claims description 6
- 230000005484 gravity Effects 0.000 claims description 6
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 claims description 6
- 239000001863 hydroxypropyl cellulose Substances 0.000 claims description 6
- 235000010977 hydroxypropyl cellulose Nutrition 0.000 claims description 6
- 239000000395 magnesium oxide Substances 0.000 claims description 6
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 6
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 6
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 claims description 6
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 6
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 6
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 6
- CHWRSCGUEQEHOH-UHFFFAOYSA-N potassium oxide Chemical compound [O-2].[K+].[K+] CHWRSCGUEQEHOH-UHFFFAOYSA-N 0.000 claims description 6
- 229910001950 potassium oxide Inorganic materials 0.000 claims description 6
- 230000001681 protective effect Effects 0.000 claims description 4
- 239000003981 vehicle Substances 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 3
- 238000002309 gasification Methods 0.000 claims description 3
- 238000004093 laser heating Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 238000012546 transfer Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 229910001873 dinitrogen Inorganic materials 0.000 claims 1
- 238000007790 scraping Methods 0.000 claims 1
- 238000010023 transfer printing Methods 0.000 abstract description 8
- 230000009286 beneficial effect Effects 0.000 abstract description 7
- 230000006872 improvement Effects 0.000 abstract description 2
- 210000002268 wool Anatomy 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 24
- 239000007864 aqueous solution Substances 0.000 description 13
- 230000008021 deposition Effects 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 11
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 10
- 229910052757 nitrogen Inorganic materials 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 7
- 239000010453 quartz Substances 0.000 description 7
- 239000007788 liquid Substances 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 4
- 238000010926 purge Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 3
- 229910021419 crystalline silicon Inorganic materials 0.000 description 3
- 229910001882 dioxygen Inorganic materials 0.000 description 3
- 238000009472 formulation Methods 0.000 description 3
- 238000003475 lamination Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000005360 phosphosilicate glass Substances 0.000 description 3
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 3
- 229920005591 polysilicon Polymers 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000007650 screen-printing Methods 0.000 description 3
- 229910000077 silane Inorganic materials 0.000 description 3
- 150000003376 silicon Chemical class 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000005641 tunneling Effects 0.000 description 3
- 238000009736 wetting Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 238000007648 laser printing Methods 0.000 description 2
- XHXFXVLFKHQFAL-UHFFFAOYSA-N phosphoryl trichloride Chemical compound ClP(Cl)(Cl)=O XHXFXVLFKHQFAL-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052810 boron oxide Inorganic materials 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Photovoltaic Devices (AREA)
Abstract
The invention discloses a solar cell intermediate, a preparation method and application thereof, wherein when the solar cell intermediate is prepared, firstly, boron atoms on the whole surface of a silicon substrate after wool making treatment are lightly doped, then an anti-reflection passivation layer is deposited, and then laminated slurry (boron slurry and metal slurry in sequence) is deposited in a contact area in a transfer printing mode, and then the laminated slurry is dried and sintered; practice shows that the method can realize boron selective doping in fewer steps, has the same width as that of the metal electrode in the heavily doped region, simplifies the process steps, is beneficial to comprehensive improvement of electrical properties, is beneficial to industrialized application, and is suitable for preparing solar cells.
Description
Technical Field
The invention relates to the field of solar cells, in particular to a solar cell intermediate, a preparation method and application thereof.
Background
At present, boron doped selective emitters are simply realized by differential boron doping in different areas on an n-type (phosphorus doped) crystalline silicon substrate, namely heavy doping is carried out in a pre-printed electrode area, and light doping is carried out in a non-printed electrode area. The conventional boron doped homogeneous junction is difficult to obtain good balance on three electrical parameters of open circuit voltage (Voc), short circuit current (Isc) and Fill Factor (FF), theoretically, the boron doped selective emitter is beneficial to obtain compatible performance, and the reason is that: the pre-printed electrode area is heavily doped, so that the series resistance (Rs) can be reduced, the Filling Factor (FF) is improved, meanwhile, the heavy doping is beneficial to reducing the recombination of slurry burning-through to the battery piece, and the open-circuit voltage (Voc) is further improved; the light doping is carried out in the non-printing electrode area, which is favorable for reducing surface recombination and promoting the rise of open-circuit voltage (Voc), and meanwhile, the short-wave response can be improved and the short-circuit current (Isc) can be promoted. Therefore, compared with boron-doped homogeneous junctions, the boron-doped selective emitter is expected to improve the photoelectric conversion efficiency of the crystalline silicon cell.
Currently, various preparation processes of boron doped selective emitters are available, including an etch-back method, a secondary diffusion method, a printing boron paste method, a laser melting BSG method and the like. However, these methods all have some common problems as follows: firstly, the steps are complicated; secondly, since the electrode is usually prepared by adopting a screen printing mode, but the screen printing precision is relatively insufficient, the width of the heavily doped region is usually required to be far larger than that of the printing electrode, the width of the heavily doped region is generally 70-120 mu m, the width of the current electrode is generally 20-30 mu m, more heavily doped regions without covering the electrode appear, and the surface recombination of the heavily doped region is obviously higher than that of the lightly doped region, so that the existence of the redundant heavily doped region can reduce the open circuit voltage.
Disclosure of Invention
It is an object of the present invention to overcome one or more of the deficiencies of the prior art and to provide an improved method for the preparation of a solar cell intermediate which enables boron selective doping with fewer steps while having a width such that the heavily doped region is substantially the same as the width of the metal electrode.
The invention also provides a solar cell intermediate prepared by the method.
The invention also provides a solar cell containing the solar cell intermediate and a preparation method thereof.
In order to achieve the above purpose, the invention adopts a technical scheme that:
a method of preparing a solar cell intermediate, the method comprising:
performing texturing treatment on the silicon substrate, and then performing boron diffusion treatment to sequentially form a uniform boron diffusion emitter and a borosilicate glass layer on the surface of the silicon substrate;
removing the borosilicate glass layer, and then depositing an anti-reflection passivation layer on the surface of the uniform boron diffusion emitter;
adopting a temperature-resistant material with a groove as a carrier, and sequentially filling metal slurry and boron slurry into the groove; wherein, the adhesion between each of the metal paste and the boron paste and the inner wall of the groove is adjusted to meet the following conditions: when the groove is inverted, the metal paste and the boron paste cannot be separated from the groove under the action of gravity;
inverting the groove, heating and gasifying organic components in the metal paste and the boron paste in a local heating mode, and enabling the boron paste and the metal paste to be separated from the groove in sequence through acting force and gravity action between gas formed after gasification and the inner wall of the groove and deposited at a preset position corresponding to a printing electrode area on the anti-reflection passivation layer;
drying at a first temperature to remove residual organic components in the boron paste and the metal paste respectively;
sintering is carried out in an aerobic environment at a second temperature, the second temperature is higher than the first temperature, a boron doped selective emitter structure and a metal electrode are obtained, and the width of a heavily doped region in the boron doped selective emitter structure is within 1% of the width of the metal electrode.
According to some preferred and specific aspects of the invention, the width of the heavily doped region in the boron doped selective emitter structure differs from the width of the metal electrode by within 0.5%.
Further, the width of the heavily doped region in the boron doped selective emitter structure is the same as the width of the metal electrode.
According to some preferred aspects of the invention, the first temperature is 200-500 ℃.
According to some preferred aspects of the invention, the second temperature is 700-900 ℃.
According to the present invention, the metal paste may be selected from commercially available metal paste components that can be used to realize laser transfer printing.
Further, in some preferred and specific embodiments of the present invention, the metal paste includes silver powder, a first glass frit, and a first organic vehicle, and optionally aluminum powder;
in the metal slurry, 92-95% of silver powder, 2-3% of first glass powder, 2-3% of first organic carrier and 0-2% of aluminum powder by mass percent.
Further, the first glass frit comprises, in mass percent: 75-80% of silicon dioxide, 5-10% of lead oxide, 3-7% of calcium oxide, 3-7% of bismuth oxide, 0-0.5% of cerium oxide and 0-0.5% of tellurium oxide.
Further, the first organic carrier includes, in mass percent: 10-20% of castor oil derivative, 10-20% of ethyl cellulose, 10-20% of alcohol ester twelve, 10-20% of tripropylene glycol methyl ether, 10-20% of polyvinyl butyral, 10-20% of polyvinylpyrrolidone, 10-20% of butyl carbitol, 10-20% of modified acrylic resin, 1-5% of epoxy resin, 1-3% of ethylene-vinyl acetate copolymer, 1-2% of polyethylene and 0-2% of polystyrene.
According to the present invention, wetting occurs when a liquid is held in contact with a solid surface, the degree to which wetting occurs (i.e., wettability) being determined by cohesion between liquid molecules and adhesion resulting from molecular interactions between liquid and solid. Wettability is typically measured by contact angle, decreasing contact angle and increasing wettability. Wettability can be explained by the relative strength of cohesion and adhesion, strong adhesion and weak cohesion resulting in very low contact angles, almost complete wetting. As the solid-liquid interaction decreases and the liquid-liquid interaction increases, the wettability decreases and the contact angle increases. The adhesion in the present invention is mainly the force between the organic carrier (liquid, mainly binder) and the inner wall (solid) of the groove in the boron slurry. The boron paste needs to meet the contact angle of 80-120 degrees. If the contact angle is smaller, the adhesive force of the boron paste is strong and the cohesive force is weak, and the boron paste flows out of the groove during back-off; the contact angle is larger, and the boron slurry back-off is separated from the groove.
Further, in some preferred embodiments of the present invention, the boron slurry comprises a boron powder, a second glass powder, and a second organic carrier;
in the boron slurry, 60-80% of boron powder, 10-25% of second glass powder and 5-10% of second organic carrier.
Further, the second glass frit comprises, in mass percent: 80 to 85 percent of silicon dioxide, 5 to 8 percent of lead oxide, 2 to 3 percent of calcium oxide, 2 to 3 percent of bismuth oxide, 0 to 2 percent of magnesium oxide, 0 to 1 percent of potassium oxide, 0 to 0.5 percent of cerium oxide and 0 to 0.5 percent of tellurium oxide.
Further, the second organic vehicle includes, in mass percent: 20-30% of ethyl cellulose, 15-20% of hydroxyethyl cellulose, 15-20% of hydroxypropyl cellulose, 10-15% of methyl methacrylate, 10-15% of modified acrylic ester, 5-8% of isopropyl alcohol, 5-8% of propylene glycol, 1-5% of epoxy resin, 1-3% of ethylene-vinyl acetate copolymer, 1-2% of polyethylene and 0-2% of polystyrene.
According to some preferred aspects of the invention, the localized heating is laser heating. Laser heating has the advantages of high energy density and capability of realizing rapid heating of local areas at fixed points.
According to some specific aspects of the invention, the carrier is a hard transparent carrier plate for laser transfer printing.
In some embodiments of the invention, a scraper or a scraper is used to fill the groove with a layer of the metal paste and a layer of the boron paste.
According to some preferred and specific aspects of the present invention, the silicon substrate is an N-type silicon wafer having a resistivity of 0.3 to 2.1 Ω·cm.
According to some preferred and specific aspects of the invention, the texturing treatment employs a 30% -50% by mass alkali solution formed by dispersing alkali in water, the alkali comprising sodium hydroxide and/or potassium hydroxide.
According to some preferred and specific aspects of the invention, the boron diffusion treatment comprises:
at 800-950 ℃, boron compound and oxygen are introduced to deposit a boron source on the silicon substrate after texturing treatment;
then heat treatment is carried out in a protective atmosphere at 950-980 ℃;
the oxidation is carried out at 980-1050 ℃ in an aerobic environment.
In some embodiments of the invention, the boron compound is introduced in an amount of 180-380sccm and the oxygen is introduced in an amount of 250-550sccm.
In some embodiments of the invention, the boron compound is boron trichloride.
In some embodiments of the invention, the protective atmosphere is formed by introducing nitrogen in an amount of 3000-4500sccm.
In some embodiments of the invention, the aerobic environment is formed by introducing oxygen in an amount of 10000-20000sccm, or the aerobic environment is an air environment.
In some embodiments of the invention, the borosilicate glass layer is removed with 15% -25% by mass of hydrofluoric acid.
In some embodiments of the present invention, the anti-reflection passivation layer is composed of an aluminum oxide layer and a silicon nitride layer disposed in this order, the thickness of the aluminum oxide layer is 1 to 10nm, and the thickness of the silicon nitride layer is 70 to 90nm.
The invention provides another technical scheme that: a solar cell intermediate prepared by the preparation method of the solar cell intermediate.
According to the invention, the solar cell intermediate comprises a boron doped selective emitter structure, wherein the boron doped selective emitter structure comprises a boron heavily doped region and a boron lightly doped region, the sheet resistance of the boron heavily doped region is 40-80 Ω/sq, and the sheet resistance of the boron lightly doped region is 180-220 Ω/sq.
The invention provides another technical scheme that: the application of the solar cell intermediate in preparing the solar cell is provided.
The invention provides another technical scheme that: the preparation method of the solar cell comprises the preparation method of the solar cell intermediate.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
based on the defects existing in the prior art when preparing the boron doped selective emitter structure, the invention innovatively provides an improved process, wherein the process comprises the steps of firstly lightly doping boron atoms on the whole surface of a silicon substrate after wool making treatment, then depositing an anti-reflection passivation layer, depositing lamination slurry (boron slurry and metal slurry in sequence) in a contact area in a transfer printing manner, and drying and sintering; practice shows that the method of the invention has at least the following advantages: 1. the steps are few, and only 2 steps of transfer printing and sintering are needed; 2. the doped slurry and the metal slurry can be well stacked, the widths can be nearly consistent, the widths of the heavily doped region and the metal electrode are basically consistent, the redundant heavily doped region can be effectively reduced, and the battery performance is further improved; the invention realizes that the width of the heavily doped region is basically the same as that of the metal electrode while preparing the boron selective doped structure, thereby greatly reducing the process steps and taking into account the electrical property; 3. the invention realizes the ordered preparation of other structures in the process of synchronously preparing the boron doped selective emitter structure and the metal electrode, directly obtains the solar cell intermediate, can introduce the preparation process of the intermediate into the preparation process of the solar cell, greatly reduces the production process and is beneficial to industrialized application.
Drawings
FIG. 1 is a schematic view of a silicon substrate according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a first intermediate obtained after the silicon substrate is subjected to the texturing treatment in the step (1) in the embodiment of the present invention;
FIG. 3 is a schematic diagram of a second intermediate obtained after boron diffusion in step (2) according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a third intermediate obtained after the removal of the surface borosilicate glass in step (3) according to the embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a fourth intermediate obtained after the deposition of the anti-reflection passivation layer in step (4) according to the embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a carrier used in the step (5) in the embodiment of the present invention;
FIG. 7 is a schematic structural diagram of the carrier filled with the metal paste and the boron paste in sequence in step (5) according to the embodiment of the present invention;
FIG. 8 is a schematic diagram showing a fifth intermediate obtained after the treatment in step (5) according to the embodiment of the present invention;
FIG. 9 is a schematic structural diagram of a solar cell intermediate obtained after the treatment in step (6) according to an embodiment of the present invention;
in the reference numerals, 1, a silicon substrate; 11. a suede structure; 2. a boron diffusion emitter; 3. a borosilicate glass layer; 4. an alumina layer; 5. a silicon nitride layer; 6. a hard transparent carrier plate for laser transfer; 61. a groove; 7. a metal paste; 8. boron slurry; 9. a metal electrode.
Detailed Description
The main conception of the invention is that: the invention creatively refers to a transfer printing method such as laser transfer printing mode to deposit metal slurry and boron slurry at the same time on the basis of primary boron diffusion, the boron slurry can be used as a heavily doped boron source, and the metal slurry and the boron slurry are transferred at the same time, thereby ensuring the effective control of a heavily doped region, realizing slurry stacking with narrower width and higher height, enabling the slurry stacking to be basically consistent with the width of a metal electrode, reducing the existence of redundant heavily doped region, further being beneficial to improving the electrical performance (including but not limited to improving open circuit voltage and the like), realizing the selective doping of boron, greatly reducing the process steps and being suitable for industrialized application.
Based on the above, the invention provides a preparation method of a solar cell intermediate, which comprises the following steps: performing texturing treatment on the silicon substrate, and then performing boron diffusion treatment to sequentially form a uniform boron diffusion emitter and a borosilicate glass layer on the surface of the silicon substrate;
removing the borosilicate glass layer, and then depositing an anti-reflection passivation layer on the surface of the uniform boron diffusion emitter;
adopting a temperature-resistant material with a groove as a carrier, and sequentially filling metal slurry and boron slurry into the groove; wherein, the adhesion between each of the metal paste and the boron paste and the inner wall of the groove is adjusted to meet the following conditions: when the groove is inverted, the metal paste and the boron paste cannot be separated from the groove under the action of gravity;
inverting the groove, heating and gasifying organic components in the metal paste and the boron paste in a local heating mode, and enabling the boron paste and the metal paste to be separated from the groove in sequence through acting force and gravity action between gas formed after gasification and the inner wall of the groove and deposited at a preset position corresponding to a printing electrode area on the anti-reflection passivation layer;
drying at a first temperature to remove residual organic components in the boron paste and the metal paste respectively;
sintering is carried out in an aerobic environment at a second temperature, the second temperature is higher than the first temperature, a boron doped selective emitter structure and a metal electrode are obtained, and the width of a heavily doped region in the boron doped selective emitter structure is within 1% of the width of the metal electrode.
The fabrication process of the present invention is further described below with reference to fig. 1-9, which illustrate only exemplary fabrication of structures on corresponding surfaces of a silicon substrate on which boron doped selective emitter structures are disposed.
Specifically, the preparation method of the solar cell intermediate comprises the following steps:
step (1): and (3) carrying out texturing treatment on the silicon substrate: firstly removing a silicon substrate damage layer, and then utilizing the anisotropism of low-concentration alkali to corrode the silicon substrate so as to form pyramid-shaped micro-morphology on the surface of the silicon substrate, wherein the pyramid size is 1-3 mu m;
the low-concentration alkali is an alkali solution with the mass percent of 30-50%, the alkali solution is formed by dispersing alkali in water, and the alkali comprises sodium hydroxide and/or potassium hydroxide;
referring to FIG. 1, a silicon substrate 1 is an N-type silicon wafer with resistivity of 0.3-2.1 Ω & cm;
the morphology of the first intermediate obtained after the texturing treatment is shown in fig. 2, and a textured structure 11 is formed on the surface of the silicon substrate 1;
step (2): performing boron diffusion treatment on the silicon substrate after texturing: placing a silicon substrate in a quartz boat, feeding the quartz boat into a quartz furnace tube, heating to a certain temperature, generating boron oxide on the surface of the silicon substrate through a boron compound and excessive oxygen, continuing heating for propulsion, and finally introducing oxygen for high-temperature oxidation, wherein the surface sheet resistance of the silicon substrate is 180-280 ohm/sq after a boron diffusion process;
further, the boron diffusion treatment process comprises the following steps:
(a) Reacting the silicon substrate subjected to the texturing treatment in the presence of a boron compound and oxygen at 800-950 ℃; the boron compound is introduced into the reactor at 180-380sccm, and the oxygen is introduced into the reactor at 250-550sccm in excess; the boron compound is boron trichloride;
(b) Then heat treatment is carried out at 950-980 ℃; wherein, nitrogen is introduced in the heat treatment process, and the flow rate of the nitrogen is 3000-4500sccm;
(c) Introducing oxygen and oxidizing at 980-1050 ℃; the oxygen gas is introduced into the reactor at 10000-20000sccm;
the structural schematic diagram of the second intermediate obtained in the boron diffusion treatment is shown in fig. 3, a boron diffusion emitter 2 and a borosilicate glass layer 3 are sequentially formed on a textured structure of a silicon substrate 1, and the boron diffusion emitter 2 has relatively uniform boron diffusion;
step (3): removing the surface borosilicate glass: firstly, removing surface phosphorosilicate glass by using an aqueous solution containing HF with a certain concentration;
the aqueous solution of HF (also called hydrofluoric acid) has a mass percentage of 18% -21%;
the structural diagram of the third intermediate obtained after the removal of the surface borosilicate glass is shown in fig. 4, the boron diffusion emitter 2 remains on the textured structure of the silicon substrate 1;
step (4): depositing an anti-reflection passivation layer on the surface of the boron diffusion emitter: the anti-reflection passivation layer consists of an aluminum oxide and silicon nitride lamination;
further, the alumina layer is deposited by adopting an atomic chemical vapor deposition method, and the deposition conditions are as follows: the reaction temperature is 280-300 ℃, the TMA pulse time is 4-10 s, H 2 The O pulse time is 5-10 s, the purging time is 10-20 s, the process flow is 10-30 sccm, and the thickness of the alumina layer is 1-10nm;
the silicon nitride layer is deposited by adopting a plasma enhanced chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature is 500-550 ℃, NH 3 ：SiH 4 ：N 2 O is 1:1:1-5:2:9, and the thickness of the silicon nitride layer is 70-90nm;
the structural schematic diagram of a fourth intermediate obtained after the deposition of the anti-reflection passivation layer is shown in fig. 5, and a boron diffusion emitter 2, an aluminum oxide layer 4 and a silicon nitride layer 5 are sequentially formed on the suede structure of the silicon substrate 1;
step (5): depositing a lamination slurry on the surface of the emitter region of the silicon wafer by laser printing: the laser transfer printing uses a hard transparent carrier plate, the grooved pattern of the carrier plate is in the shape of hollowed equidistant grid lines, a layer of metal slurry is filled into the groove through a scraper or a scraper, a layer of burnthrough boron slurry is filled, and the boron slurry contains glass powder in a certain proportion; and then inverting and using laser to scan, wherein organic components in the slurry in the carrier plate groove are heated and volatilized due to the action of high-energy laser, so that the carrier plate groove generates larger recoil pressure, the slurry is impacted to be desorbed from the groove and deposited on the anti-reflection passivation layer, and the silicon substrate is sequentially provided with a silicon substrate, a boron diffusion emitter, the anti-reflection passivation layer, boron slurry and metal slurry.
The grooving graph of the carrier plate can meet the customization requirement, and is designed according to the requirement; as shown in fig. 6, the carrier is a hard transparent carrier 6 for laser transfer with grooves 61, and the number and the pitch of the grooves 61 are set as required; fig. 7 is a schematic view of the metal paste 7 and the boron paste 8 after filling, wherein the metal paste 7 is positioned below the boron paste 8; when the carrier plate is inverted and laser scanning is carried out, boron paste and metal paste are deposited on the anti-reflection passivation layer, the structure of a fifth intermediate obtained after treatment is shown in fig. 8, a boron diffusion emitter 2, an aluminum oxide layer 4 and a silicon nitride layer 5 are sequentially formed on a suede structure of a silicon substrate 1, and then a plurality of laminated combinations formed from bottom to top are deposited on the silicon nitride layer 5, wherein each laminated combination is formed from boron paste 8 and metal paste 7 from bottom to top;
the metal slurry comprises silver powder, first glass powder, a first organic carrier and optional aluminum powder;
in the metal slurry, 92-95% of silver powder, 2-3% of first glass powder, 2-3% of first organic carrier and 0-2% of aluminum powder by mass percent;
further, the first glass frit comprises, in mass percent: 75-80% of silicon dioxide, 5-10% of lead oxide, 3-7% of calcium oxide, 3-7% of bismuth oxide, 0-0.5% of cerium oxide and 0-0.5% of tellurium oxide;
further, the first organic carrier includes, in mass percent: 10-20% of castor oil derivative, 10-20% of ethyl cellulose, 10-20% of alcohol ester twelve, 10-20% of tripropylene glycol methyl ether, 10-20% of polyvinyl butyral, 10-20% of polyvinylpyrrolidone, 10-20% of butyl carbitol, 10-20% of modified acrylic resin, 1-5% of epoxy resin, 1-3% of ethylene-vinyl acetate copolymer, 1-2% of polyethylene and 0-2% of polystyrene;
the aluminum powder is pure spherical or flaky aluminum powder or aluminum powder particles with the surfaces coated by aluminum oxide;
the boron slurry comprises boron powder, second glass powder and a second organic carrier;
in the boron slurry, 60-80% of boron powder, 10-25% of second glass powder and 5-10% of second organic carrier by mass percent;
further, the second glass frit comprises, in mass percent: 80-85% of silicon dioxide, 5-8% of lead oxide, 2-3% of calcium oxide, 2-3% of bismuth oxide, 0-2% of magnesium oxide, 0-1% of potassium oxide, 0-0.5% of cerium oxide and 0-0.5% of tellurium oxide;
further, the second organic vehicle includes, in mass percent: 20-30% of ethyl cellulose, 15-20% of hydroxyethyl cellulose, 15-20% of hydroxypropyl cellulose, 10-15% of methyl methacrylate, 10-15% of modified acrylic ester, 5-8% of isopropyl alcohol, 5-8% of propylene glycol, 1-5% of epoxy resin, 1-3% of ethylene-vinyl acetate copolymer, 1-2% of polyethylene and 0-2% of polystyrene.
The working parameters of the laser scanning are as follows: red light, laser power of 25-30W and scanning time of 0.8-1 s;
step (6): low temperature baking (treatment at first temperature) and high temperature sintering (treatment at second temperature) of the silicon substrate of the deposition slurry: the low-temperature drying temperature is 200-500 ℃, so as to volatilize the residual organic components in the slurry at present; the high-temperature sintering temperature is 700-900 ℃, so that glass powder in the boron slurry is softened to corrode the anti-reflection passivation layer, the boron slurry is directly contacted with the boron diffusion emitter, boron element in the boron slurry is diffused into the surface of the silicon substrate at high temperature, so that heavy doping is formed in a printing slurry area, meanwhile, metal powder (such as silver powder and aluminum powder) in the upper-layer metal slurry is wrapped by the glass powder at high temperature and moves downwards along with the softening flow of the glass powder, the glass powder is directly contacted with the silicon substrate emitter to generate oxidation-reduction reaction, metal is deposited on the silicon substrate, and a recrystallized metal phase is separated in the cooling process after sintering; the metal electrode is contacted with the heavily doped region of the emitter, the widths of the metal electrode and the heavily doped region are basically consistent, and no redundant heavily doped region exists basically;
as shown in fig. 9, the structure of the finally produced solar cell intermediate is that a boron diffusion emitter 2, an alumina layer 4 and a silicon nitride layer 5 are sequentially formed on a textured structure of a silicon substrate 1, and a heavily doped region and a metal electrode 9 substantially overlapping the heavily doped region are provided on the boron diffusion emitter 2 (the slurry contact region is a heavily doped region, and the non-contact region is a lightly doped region).
The above-described aspects are further described below in conjunction with specific embodiments; it should be understood that these embodiments are provided to illustrate the basic principles, main features and advantages of the present invention, and that the present invention is not limited by the scope of the following embodiments; the implementation conditions employed in the examples may be further adjusted according to specific requirements, and the implementation conditions not specified are generally those in routine experiments.
All starting materials are commercially available or prepared by methods conventional in the art, not specifically described in the examples below.
Example 1
The solar cell intermediate is prepared by adopting the structure and the process shown in the combination of fig. 1 to 9, and specific parameters are as follows:
step (1): the resistivity of the N-type silicon wafer is 1.5 omega cm; the low-concentration alkali is sodium hydroxide aqueous solution with the mass percent of 46%;
step (2): the boron diffusion treatment process comprises the following steps:
(a) Reacting the silicon substrate subjected to the texturing treatment in the presence of boron trichloride and oxygen at 980 ℃; the boron trichloride is introduced into the reactor at 340sccm, and the oxygen is introduced into the reactor at 400sccm excess;
(b) Then heat treatment is carried out at 960 ℃; introducing nitrogen in the heat treatment process, wherein the flow rate of the nitrogen is 4000sccm;
(c) Introducing oxygen and oxidizing at 1000 ℃; the oxygen inlet amount is 10000sccm;
the surface sheet resistance of the silicon substrate after the boron diffusion process is 210 omega/sq;
step (3): the mass percentage of the aqueous solution of HF is 19%;
step (4): the alumina layer is deposited by adopting an atomic chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature 290 ℃, TMA pulse time 6s, H 2 O pulse time 7s, purge time 18s, process flow 22sccm; the thickness of the alumina layer is 5nm;
the silicon nitride layer is deposited by adopting a plasma enhanced chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature 530 ℃, NH 3 ：SiH 4 ：N 2 O is 4:2:7; the thickness of the silicon nitride layer is 80nm;
step (5): the formula content of the metal slurry is as follows in percentage by mass: 94% of silver powder, 2% of first glass powder, 3% of first organic carrier and 1% of aluminum powder. Wherein, the silicon dioxide in the first glass powder is 79%, the lead oxide is 8%, the calcium oxide is 6.3%, the bismuth oxide is 6.3%, the cerium oxide is 0.3% and the tellurium oxide is 0.1%; 13% of castor oil derivative, 10% of ethyl cellulose, 12% of alcohol ester twelve, 11% of tripropylene glycol methyl ether, 12% of polyvinyl butyral, 11% of polyvinylpyrrolidone, 15% of butyl carbitol, 12% of modified acrylic resin, 1.5% of epoxy resin, 1% of ethylene-vinyl acetate copolymer, 1% of polyethylene and 0.5% of polystyrene;
the formulation content of the boron paste is as follows: 75% of boron powder, 20% of second glass powder and 5% of second organic carrier; wherein, in the second glass powder, 84 percent of silicon dioxide, 7 percent of lead oxide, 2.5 percent of calcium oxide, 2.5 percent of bismuth oxide, 2 percent of magnesium oxide, 1 percent of potassium oxide, 0.5 percent of cerium oxide and 0.5 percent of tellurium oxide; 20% of ethyl cellulose, 20% of hydroxyethyl cellulose, 15% of hydroxypropyl cellulose, 15% of methyl methacrylate, 15% of modified acrylic ester, 5% of isopropanol, 5% of propylene glycol, 2% of epoxy resin, 2% of ethylene-vinyl acetate copolymer and 1% of polyethylene in a second organic carrier;
the working parameters of the laser scanning are as follows: red light, laser power 25W, scanning time 1s;
step (6): the low-temperature drying temperature is 380 ℃, the treatment time is 10s, the high-temperature sintering temperature is 730 ℃, and the treatment time is 0.8s.
And (3) measuring: the sheet resistance of the heavily doped region is 65Ω/sq, and the sheet resistance of the lightly doped region is 210Ω/sq.
Example 2
The solar cell intermediate is prepared by adopting the structure and the process shown in the combination of fig. 1 to 9, and specific parameters are as follows:
step (1): the resistivity of the N-type silicon wafer is 1.5 omega cm; the low-concentration alkali is sodium hydroxide aqueous solution with the mass percent of 46%;
step (2): the boron diffusion treatment process comprises the following steps:
(a) Reacting the silicon substrate subjected to the texturing treatment in the presence of boron trichloride and oxygen at 980 ℃; the boron trichloride is introduced into the reactor at 340sccm, and the oxygen is introduced into the reactor at 400sccm excess;
(b) Then heat treatment is carried out at 960 ℃; introducing nitrogen in the heat treatment process, wherein the flow rate of the nitrogen is 4000sccm;
(c) Introducing oxygen and oxidizing at 1000 ℃; the oxygen gas is introduced into the reactor at 15000sccm;
the surface sheet resistance of the silicon substrate after the boron diffusion process is 210 omega/sq;
step (3): the mass percentage of the aqueous solution of HF is 20%;
step (4): the alumina layer is deposited by adopting an atomic chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature 290 ℃, TMA pulse time 6s, H 2 O pulse time 7s, purge time 18s, process flow 22sccm; the thickness of the alumina layer is 5nm;
the silicon nitride layer is deposited by adopting a plasma enhanced chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature 530 ℃, NH 3 ：SiH 4 ：N 2 O is 4:2:7; the thickness of the silicon nitride layer is 80nm;
step (5): the formula content of the metal slurry is as follows in percentage by mass: 94% of silver powder, 2% of glass powder and 3% of organic carrier. 1% of aluminum powder. Wherein, 78 percent of silicon dioxide, 9.5 percent of lead oxide, 6 percent of calcium oxide, 5.5 percent of bismuth oxide, 0.5 percent of cerium oxide and 0.5 percent of tellurium oxide in the glass powder; 12% of castor oil derivative, 11% of ethyl cellulose, 13.5% of alcohol ester twelve, 12.5% of tripropylene glycol methyl ether, 13% of polyvinyl butyral, 12% of polyvinylpyrrolidone, 12% of butyl carbitol, 10% of modified acrylic resin, 1% of epoxy resin, 1% of ethylene-vinyl acetate copolymer and 2% of polyethylene in an organic carrier;
the formulation content of the boron paste is as follows: 75% of boron powder, 20% of glass powder and 5% of organic carrier; wherein, the glass powder comprises 82 percent of silicon dioxide, 8 percent of lead oxide, 3 percent of calcium oxide, 3 percent of bismuth oxide, 2 percent of magnesium oxide, 1 percent of potassium oxide, 0.5 percent of cerium oxide and 0.5 percent of tellurium oxide; 25% of ethyl cellulose, 15% of hydroxyethyl cellulose, 18% of hydroxypropyl cellulose, 12% of methyl methacrylate, 10% of modified acrylic ester, 6% of isopropanol, 6% of propylene glycol, 3% of epoxy resin, 2% of ethylene-vinyl acetate copolymer, 2% of polyethylene and 1% of polystyrene;
the working parameters of the laser scanning are as follows: red light, laser power of 30W and scanning time of 0.8s;
step (6): the low-temperature drying temperature is 380 ℃, the treatment time is 10s, the high-temperature sintering temperature is 730 ℃, and the treatment time is 0.8s.
And (3) measuring: the sheet resistance of the heavily doped region is 60 Ω/sq, and the sheet resistance of the lightly doped region is 220 Ω/sq.
Example 3
The solar cell intermediate is prepared by adopting the structure and the process shown in the combination of fig. 1 to 9, and specific parameters are as follows:
step (1): the resistivity of the N-type silicon wafer is 1.5 omega cm; the low-concentration alkali is sodium hydroxide aqueous solution with the mass percent of 46%;
step (2): the boron diffusion treatment process comprises the following steps:
(a) Reacting the silicon substrate subjected to the texturing treatment in the presence of boron trichloride and oxygen at 920 ℃; the boron trichloride is introduced into the reactor at 360sccm, and the oxygen is introduced into the reactor at 500sccm excess;
(b) Then heat treatment is carried out at 900 ℃; introducing nitrogen in the heat treatment process, wherein the flow rate of the nitrogen is 4500sccm;
(c) Introducing oxygen and oxidizing at 1050 ℃; the oxygen gas is introduced into the reactor at 15000sccm;
the surface sheet resistance of the silicon substrate after the boron diffusion process is 220 omega/sq;
step (3): the mass percentage of the aqueous solution of HF is 18%;
step (4): the alumina layer is deposited by adopting an atomic chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature 290 ℃, TMA pulse time 6s, H 2 O pulse time 7s, purging time 18s, process flow 22sccm, thickness of the alumina layer 5nm;
the silicon nitride layer is deposited by adopting a plasma enhanced chemical vapor deposition method, and the deposition conditions are as follows: reaction temperature 530 ℃, NH 3 ：SiH 4 ：N 2 O is 4:2:7, and the thickness of the silicon nitride layer is 80nm;
step (5): the formula content of the metal slurry is as follows in percentage by mass: 94% of silver powder, 2% of glass powder and 3% of organic carrier. 1% of aluminum powder. Wherein, the silicon dioxide in the glass powder is 79%, the lead oxide is 10%, the calcium oxide is 5.5% and the bismuth oxide is 5.5%; 11% of castor oil derivative, 11% of ethyl cellulose, 12% of alcohol ester twelve, 11% of tripropylene glycol methyl ether, 14% of polyvinyl butyral, 12% of polyvinylpyrrolidone, 12% of butyl carbitol, 12% of modified acrylic resin, 1.5% of epoxy resin, 1.5% of ethylene-vinyl acetate copolymer, 1.5% of polyethylene and 0.5% of polystyrene;
the formulation content of the boron paste is as follows: 75% of boron powder, 20% of glass powder and 5% of organic carrier; wherein, 85 percent of silicon dioxide, 6 percent of lead oxide, 3 percent of calcium oxide, 3 percent of bismuth oxide, 1.5 percent of magnesium oxide, 1 percent of potassium oxide and 0.5 percent of cerium oxide in the glass powder; 23% of ethyl cellulose, 16% of hydroxyethyl cellulose, 16% of hydroxypropyl cellulose, 14% of methyl methacrylate, 12% of modified acrylic ester, 5% of isopropanol, 6% of propylene glycol, 3% of epoxy resin, 2% of ethylene-vinyl acetate copolymer, 2% of polyethylene and 1% of polystyrene;
the working parameters of the laser scanning are as follows: red light, laser power of 30W and scanning time of 0.8s;
step (6): the low-temperature drying temperature is 380 ℃, the treatment time is 10s, the high-temperature sintering temperature is 730 ℃, and the treatment time is 0.8s.
And (3) measuring: the sheet resistance of the heavily doped region is 65Ω/sq, and the sheet resistance of the lightly doped region is 205 Ω/sq.
Comparative example 1
Substantially the same as in example 1, the only difference is that: boron slurry commonly used for boron diffusion in the prior art is adopted. And (3) measuring: the sheet resistance of the heavily doped region is 120 Ω/sq, and the sheet resistance of the lightly doped region is 300 Ω/sq.
Comparative example 2
Substantially the same as in example 1, the only difference is that: sintering is accomplished without boron slurry, using only conventional metal slurries.
Performance testing
To further demonstrate the performance improvement afforded by the methods described in this patent, the preparation process and performance test results of the N-TOPCon batteries comprising examples 1-3 and comparative examples 1-2 described above were supplemented as follows:
1. corresponding to the step (1): the resistivity of the N-type silicon wafer is 1.5 omega cm; the low-concentration alkali is sodium hydroxide aqueous solution with the mass percent of 46%;
2. corresponding to the step (2): the boron diffusion treatment process (specific process parameters are implemented in examples and comparative examples)
3. Corresponding to the step (3): removing borosilicate glass, wherein the mass percentage of the aqueous solution of HF is 18%;
4. inserting the intermediate of the passivated contact crystalline silicon battery into a quartz boat, feeding the quartz boat into a quartz tube, heating to 610 ℃, and then oxidizing the quartz tube at normal pressure to form a tunneling silicon oxide layer, wherein the thickness of the tunneling silicon oxide layer is 1.4nm; then evacuating oxygen, controlling the temperature to 630 ℃ and the pressure to be 30Pa, introducing silane for low-pressure chemical vapor deposition, wherein the silane flow is 920sccm, the polysilicon deposition rate is 4.8nm/min, and the silane is SiH 4 The thickness of the deposited polysilicon layer is 120nm;
5. the inlet amount of phosphorus oxychloride is 1400sccm, the inlet amount of oxygen is 600sccm, the temperature is 880 ℃, the treatment time is 3200s, and the thickness of the phosphosilicate glass layer is 40nm;
6. removing the front and edge phosphosilicate glass layer 7 by using 10% hydrofluoric acid aqueous solution; removing the polysilicon layer on the front side and the edge by using a sodium hydroxide aqueous solution with the mass percentage of 2.4% at 66 ℃; removing the tunneling oxide layer on the front side, the borosilicate glass layer on the front side and the phosphosilicate glass layer on the back side by using a hydrofluoric acid aqueous solution with the mass percentage of 20%;
7. corresponding to the step (4): deposition of an anti-reflection passivation layer (specific process parameters are performed as in the examples/comparative examples);
8. printing back main grids by using a screen printing mode, wherein the number of the main grids is 16, the width of the main grids is 60 mu m, then printing back fine grids with 200 grid lines, the line width of 30 mu m and the grid line spacing of 0.91mm after drying, printing front main grids with the number of the main grids being 16 and the width of the main grids being 60 mu m after drying, and then drying;
9. corresponding to the step (5): laser printing (specific parameter information is performed in accordance with examples/comparative examples);
10. corresponding to the step (6): oven-dry sintering (specific sintering parameters are performed according to examples/comparative examples);
the testing method comprises the following steps: and testing the photoelectric conversion efficiency and related electrical performance parameters of the battery under the standard illumination power by using an IV tester under the simulated solar light source.
The specific test results are shown in Table 1 (Eta; conversion efficiency, voc: open circuit voltage, isc: short circuit current, FF: fill factor).
TABLE 1
As shown in table 1, after the intermediate prepared by the method is applied to a solar cell, particularly an N-TOPCon cell, the conversion efficiency of the cell can be remarkably improved, that is, the method can enable the doped slurry and the metal slurry to be well stacked, the width can be nearly consistent, the width of the heavily doped region is basically consistent with that of the metal electrode, the redundant heavily doped region can be effectively reduced, and the cell performance is further improved. In addition, the invention realizes the orderly preparation of other structures in the process of synchronously preparing the boron doped selective emitter structure and the metal electrode, directly obtains the solar cell intermediate, can introduce the preparation process of the intermediate into the preparation process of the solar cell, greatly reduces the production process and is beneficial to industrialized application.
The above embodiments are provided to illustrate the technical concept and features of the present invention and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
Claims (17)
1. The preparation method of the solar cell intermediate is characterized by comprising the following steps of:
performing texturing treatment on the silicon substrate, and then performing boron diffusion treatment to sequentially form a uniform boron diffusion emitter and a borosilicate glass layer on the surface of the silicon substrate;
removing the borosilicate glass layer, and then depositing an anti-reflection passivation layer on the surface of the uniform boron diffusion emitter;
adopting a temperature-resistant material with a groove as a carrier, and sequentially filling metal slurry and boron slurry into the groove; wherein, the adhesion between each of the metal paste and the boron paste and the inner wall of the groove is adjusted to meet the following conditions: when the groove is inverted, the metal paste and the boron paste cannot be separated from the groove under the action of gravity;
inverting the groove, heating and gasifying organic components in the metal paste and the boron paste in a local heating mode, and enabling the boron paste and the metal paste to be separated from the groove in sequence through acting force and gravity action between gas formed after gasification and the inner wall of the groove and deposited at a preset position corresponding to a printing electrode area on the anti-reflection passivation layer;
drying at a first temperature to remove residual organic components in the boron paste and the metal paste respectively;
sintering is carried out in an aerobic environment at a second temperature, the second temperature is higher than the first temperature, a boron doped selective emitter structure and a metal electrode are obtained, and the width of a heavily doped region in the boron doped selective emitter structure is within 1% of the width of the metal electrode.
2. The method of claim 1, wherein the width of the heavily doped region in the boron doped selective emitter structure differs from the width of the metal electrode by within 0.5%.
3. The method of claim 1, wherein the first temperature is 200-500 ℃.
4. A method of preparing a solar cell intermediate according to claim 1 or 3, wherein the second temperature is 700-900 ℃.
5. The method of claim 1, wherein the metal paste comprises silver powder, a first glass frit, a first organic vehicle, and optionally aluminum powder;
in the metal slurry, 92-95% of silver powder, 2-3% of first glass powder, 2-3% of first organic carrier and 0-2% of aluminum powder by mass percent;
the first glass powder comprises the following components in percentage by mass: 75-80% of silicon dioxide, 5-10% of lead oxide, 3-7% of calcium oxide, 3-7% of bismuth oxide, 0-0.5% of cerium oxide and 0-0.5% of tellurium oxide;
the first organic carrier comprises, in mass percent: 10-20% of castor oil derivative, 10-20% of ethyl cellulose, 10-20% of alcohol ester twelve, 10-20% of tripropylene glycol methyl ether, 10-20% of polyvinyl butyral, 10-20% of polyvinylpyrrolidone, 10-20% of butyl carbitol, 10-20% of modified acrylic resin, 1-5% of epoxy resin, 1-3% of ethylene-vinyl acetate copolymer, 1-2% of polyethylene and 0-2% of polystyrene.
6. The method of preparing a solar cell intermediate according to claim 1 or 5, wherein the boron slurry comprises a boron powder, a second glass powder and a second organic carrier;
in the boron slurry, 60-80% of boron powder, 10-25% of second glass powder and 5-10% of second organic carrier by mass percent;
the second glass powder comprises the following components in percentage by mass: 80-85% of silicon dioxide, 5-8% of lead oxide, 2-3% of calcium oxide, 2-3% of bismuth oxide, 0-2% of magnesium oxide, 0-1% of potassium oxide, 0-0.5% of cerium oxide and 0-0.5% of tellurium oxide;
the second organic carrier comprises, in mass percent: 20-30% of ethyl cellulose, 15-20% of hydroxyethyl cellulose, 15-20% of hydroxypropyl cellulose, 10-15% of methyl methacrylate, 10-15% of modified acrylic ester, 5-8% of isopropyl alcohol, 5-8% of propylene glycol, 1-5% of epoxy resin, 1-3% of ethylene-vinyl acetate copolymer, 1-2% of polyethylene and 0-2% of polystyrene.
7. The method for preparing a solar cell intermediate according to claim 1, wherein the local heating is laser heating.
8. The method for producing a solar cell intermediate according to claim 1 or 7, wherein the carrier is a hard transparent carrier for laser transfer; and/or filling a layer of the metal slurry into the groove by adopting a scraper or a scraping plate, and refilling a layer of the boron slurry.
9. The method for preparing a solar cell intermediate according to claim 1, wherein the silicon substrate is an N-type silicon wafer having a resistivity of 0.3-2.1 Ω -cm; and/or, the texturing treatment adopts an alkali solution with the mass percent of 30-50%, wherein the alkali solution is formed by dispersing alkali in water, and the alkali comprises sodium hydroxide and/or potassium hydroxide.
10. The method for producing a solar cell intermediate according to claim 1, wherein the boron diffusion treatment comprises:
at 800-950 ℃, boron compound and oxygen are introduced to deposit a boron source on the silicon substrate after texturing treatment;
then heat treatment is carried out in a protective atmosphere at 950-980 ℃;
the oxidation is carried out at 980-1050 ℃ in an aerobic environment.
11. The method for producing a solar cell intermediate according to claim 10, wherein the amount of the boron compound introduced is 180-380sccm and the amount of the oxygen introduced is 250-550sccm; and/or the boron compound is boron trichloride.
12. The method for producing a solar cell intermediate according to claim 10, wherein the protective atmosphere is formed by introducing nitrogen gas in an amount of 3000-4500sccm; and/or the aerobic environment is formed by introducing oxygen, the introducing amount of the oxygen is 10000-20000sccm, or the aerobic environment is an air environment.
13. The method for preparing a solar cell intermediate according to claim 1, wherein the borosilicate glass layer is removed by using 15-25% by mass of hydrofluoric acid; and/or the anti-reflection passivation layer consists of an aluminum oxide layer and a silicon nitride layer which are sequentially arranged, wherein the thickness of the aluminum oxide layer is 1-10nm, and the thickness of the silicon nitride layer is 70-90nm.
14. A solar cell intermediate made by the method of making a solar cell intermediate of any one of claims 1-13.
15. The solar cell intermediate of claim 14, comprising a boron doped selective emitter structure comprising a boron heavily doped region and a boron lightly doped region, wherein the sheet resistance of the boron heavily doped region is 40-80 Ω/sq and the sheet resistance of the boron lightly doped region is 180-220 Ω/sq.
16. Use of a solar cell intermediate according to claim 14 or 15 for the preparation of a solar cell.
17. A method for producing a solar cell, characterized in that the method for producing a solar cell comprises the method for producing a solar cell intermediate according to any one of claims 1 to 13.
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