CN114464708A - Heterojunction solar cell and preparation method thereof - Google Patents
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- 238000002360 preparation method Methods 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 claims abstract description 97
- 230000008569 process Effects 0.000 claims abstract description 83
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 68
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims abstract description 57
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 47
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- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 28
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 16
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- 238000002834 transmittance Methods 0.000 claims description 6
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Abstract
The application relates to the technical field of photovoltaic cells, and discloses a heterojunction solar cell and a preparation method thereof, wherein the preparation method comprises the following steps: forming a silicon dioxide tunnel passivation layer on the front side and the back side of the N-type monocrystalline silicon wafer respectively by taking the N-type monocrystalline silicon wafer as a substrate; forming an N-type polycrystalline silicon carbide layer with wide band gap on the front surface of the N-type monocrystalline silicon wafer; forming a P-type polycrystalline silicon layer on the reverse side of the N-type monocrystalline silicon wafer; respectively forming boron-doped zinc oxide layers on the front side and the back side of the N-type monocrystalline silicon wafer; and forming metal electrodes on the boron-doped zinc oxide layers on the front surface and the back surface of the N-type monocrystalline silicon wafer. The preparation method of the heterojunction solar cell provided by the application does not need a texturing process, so that the pollution of metal ions to a cell piece and the treatment process of KOH waste liquid are avoided, the performance of the heterojunction solar cell is improved, and meanwhile, the production cost is reduced.
Description
Technical Field
The application relates to the technical field of photovoltaic cells, and mainly relates to a heterojunction solar cell and a preparation method thereof.
Background
Since the heterojunction solar cell (HJT cell) technology has the advantages of simple process, high open-circuit voltage, high conversion efficiency, low process temperature, low temperature coefficient, no light attenuation and electroattenuation, etc., the technology is favored by the industry, and nearly 30 enterprises which have mass-produced or planned mass-produced heterojunction solar cells worldwide have planned production capacity, the planned production capacity exceeds 50GW, and the actual production capacity reaches about 3 GW.
As shown in fig. 1, in the conventional HJT cell technology, an N-type silicon wafer 1 (N-Si) is used as a substrate, an intrinsic hydrogen-rich amorphous silicon layer 2, an N-type doped layer 3, and a transparent conductive layer 5 are formed on one side of the substrate, an intrinsic hydrogen-rich amorphous silicon layer 2, a P-type doped layer 4, and a transparent conductive layer (TCO) 5 are formed on the other side of the substrate, and a silver electrode 6 is further disposed on the outer side of the transparent conductive layer to collect current. The preparation process of the conventional HJT cell technology mainly comprises four links of cleaning and texturing, amorphous silicon deposition, TCO deposition and silk-screen curing. The technology to be solved in the existing HJT battery technology mainly has the following three aspects:
firstly, a pyramid structure is formed on the surface of an N-type silicon wafer 1 of the conventional HJT cell through a KOH texturing process to improve the sunlight scattering effect of the N-type silicon wafer 1, so as to improve the sunlight absorption capacity of the solar cell, but metal ions introduced in the KOH texturing process affect the cell performance, and the KOH waste liquid needs to be specially treated to avoid polluting the environment.
Secondly, the conventional HJT cell generally adopts a PECVD process to prepare an amorphous silicon thin film (including the intrinsic hydrogen-rich amorphous silicon layer 2, the N-type doped layer 3, and the P-type doped layer 4) to achieve a passivation effect, but the process has high requirements on the stability and uniformity of a plasma field. Moreover, the performance of the amorphous silicon thin film can be degraded at a temperature higher than 200 ℃, which results in that the HJT battery can only adopt high-cost low-temperature silver paste in the subsequent preparation process.
Finally, in the prior art, the transparent conductive layer mostly adopts an ITO film (multilayer indium tin oxide film) as the TCO on both sides. The existing HJT battery generally adopts a PVD (physical vapor deposition) process to prepare an ITO (indium tin oxide) thin film, so that on one hand, the PVD process can damage an amorphous silicon thin film and influence the passivation effect of the amorphous silicon thin film; on the other hand, the ITO thin film contains a rare element In as a raw material, which results In a high battery production cost.
Accordingly, the prior art is yet to be improved and developed.
Disclosure of Invention
In view of the defects of the prior art, the present application aims to provide a heterojunction solar cell and a preparation method thereof, and aims to solve the problems of environmental pollution and high production cost of the existing heterojunction solar cell preparation process.
The technical scheme of the application is as follows:
a preparation method of a heterojunction solar cell comprises the following steps:
(1) forming a silicon dioxide tunnel passivation layer on the front side and the back side of the N-type monocrystalline silicon wafer respectively by taking the N-type monocrystalline silicon wafer as a substrate;
(2) forming an N-type polycrystalline silicon carbide layer with wide band gap on the front surface of the N-type monocrystalline silicon wafer;
(3) forming a P-type polycrystalline silicon layer on the reverse side of the N-type monocrystalline silicon wafer;
(4) respectively forming boron-doped zinc oxide layers on the front side and the back side of the N-type monocrystalline silicon wafer;
(5) and forming metal electrodes on the boron-doped zinc oxide layers on the front surface and the back surface of the N-type monocrystalline silicon wafer.
Through optimizing heterojunction solar cell's structure and technology combination in this application for the heterojunction solar cell of this application need not the making herbs into wool process, thereby has avoided metal ion to the pollution of battery piece and the processing procedure of KOH waste liquid, has reduced manufacturing cost again when promoting heterojunction solar cell's performance.
The preparation method of the heterojunction solar cell comprises the step of preparing a silicon dioxide tunnel passivation layer, wherein the thickness of the silicon dioxide tunnel passivation layer is 5-10 nm.
The silicon dioxide tunnel passivation layer with the thickness can passivate the defects on the surface of the N-type monocrystalline silicon wafer and can form a tunnel heterojunction to ensure the collection of charges.
The preparation method of the heterojunction solar cell comprises the steps that the silicon dioxide tunnel passivation layer is formed in a plasma oxidation mode, the power frequency is set to be 2.45GHz, the pressure is set to be 0.1-50mbar, the electron temperature is 1-5eV, the ion temperature is less than 0.5eV, and the electron density is 10 eV9-1012/cm3The ionization rate is 0.1-1%.
The preparation method of the heterojunction solar cell is characterized in that the thickness of the N-type polycrystalline SiC layer with the wide band gap is 10-20 nm.
The preparation method of the heterojunction solar cell comprises the steps that the N-type polycrystalline SiC layer with the wide band gap is formed in a medium-frequency magnetron sputtering mode, the temperature is set to be 200 ℃, the power frequency is set to be 40KHz, the power is set to be 1500W, the pressure is set to be 0.1-50mbar, and SiH is used4、PH3、CH4As a process gas, the SiH4、PH3、CH4The process gas flow ratio of (1) is Si: c: p =1:1.2:0.05, or in SiH4、NH3、CH4As a process gas, the SiH4、NH3、CH4The process gas flow ratio of (1) is Si: c: n =1:1.2: 0.05; the band gap width of the N-type polycrystalline SiC layer with the wide band gap is 3-4.4eV, and the mobility is 1-10cm2V.s) doping concentration of 1017-1019/cm3。
The preparation method of the heterojunction solar cell comprises the step of preparing a P-type polycrystalline silicon layer, wherein the thickness of the P-type polycrystalline silicon layer is 10-20 nm.
The preparation method of the heterojunction solar cell comprises the steps that the P-type polycrystalline silicon layer is formed in a medium-frequency magnetron sputtering mode, the temperature is set to be 200 ℃, the power frequency is set to be 40KHz, the power is set to be 1500W, the pressure is set to be 0.1-50mbar, and SiH is used4、BH3As a process gas, the SiH4、BH3With a process gas flow ratio of Si: B =1:0.05, or with SiH4、B2H6As a process gas, the SiH4、B2H6The process gas flow ratio of (1) is Si: B =1: 0.05; the mobility of the P-type polycrystalline silicon layer is 1-10cm2V.s) doping concentration of 1017-1019/cm3。
The preparation method of the heterojunction solar cell comprises the step of preparing a boron-doped zinc oxide layer, wherein the thickness of the boron-doped zinc oxide layer is 100-500 nm.
The preparation method of the heterojunction solar cell comprises the following steps of forming a boron-doped zinc oxide layer by adopting a low-pressure chemical vapor deposition mode, setting the temperature at 200 ℃ and the pressure at 50mbar, taking water vapor, diethyl zinc and diborane as process gases, wherein the flow ratio of the process gases of the diethyl zinc and the diborane is Zn: B =1: 0.05; the square resistance of the boron-doped zinc oxide layer is less than 20 omega, and the visible light transmittance is more than 85 percent.
A heterojunction solar cell is prepared by the preparation method of the heterojunction solar cell, and comprises an N-type monocrystalline silicon wafer;
a silicon dioxide tunnel passivation layer, a wide-band-gap N-type polycrystalline silicon carbide layer, a boron-doped zinc oxide layer and a metal electrode are sequentially arranged on the front surface of the N-type monocrystalline silicon wafer from inside to outside;
and a silicon dioxide tunnel passivation layer, a P-type polycrystalline silicon layer, a boron-doped zinc oxide layer and a metal electrode are sequentially arranged on the reverse side of the N-type monocrystalline silicon wafer from inside to outside.
Has the advantages that: the preparation method of the heterojunction solar cell provided by the application comprises the steps that through an optimization process, an N-type polycrystalline silicon carbide layer with a wide band gap serves as a window layer and an electron transmission layer, a P-type polycrystalline silicon layer serves as a hole transmission layer and a BZO serves as a TCO electrode, so that the heterojunction solar cell does not need a texturing process, the pollution of metal ions to a cell piece and the processing process of KOH waste liquid are avoided, the performance of the heterojunction solar cell is improved, and meanwhile, the production cost is reduced.
Drawings
Fig. 1 is a schematic structural diagram of a heterojunction solar cell in the prior art.
Fig. 2 is a schematic structural diagram of a heterojunction solar cell of the present application.
Description of reference numerals: 1. an N-type silicon wafer; 2. an intrinsic hydrogen-rich amorphous silicon layer; 3. an N-type doped layer; 4. a P-type doped layer; 5. a transparent conductive layer; 6. a silver electrode; 11. an N-type monocrystalline silicon wafer; 12. a silicon dioxide tunnel passivation layer; 13. an N-type polycrystalline silicon carbide layer with a wide band gap; 14. a P-type polysilicon layer; 15. a boron-doped zinc oxide layer; 16. and a metal electrode.
Detailed Description
The present application provides a heterojunction solar cell and a method for manufacturing the same, and the purpose, technical solution and effect of the present application are more clear and definite, and the present application is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The application provides a preparation method of a heterojunction solar cell, which comprises the following steps:
(1) forming silicon dioxide (SiO) on the front and back of N-type monocrystalline silicon wafer as substrate2) A tunnel passivation layer.
In this step, SiO is used2The passivation effect on the surface of the N-type monocrystalline silicon piece is realized by replacing amorphous silicon. Due to SiO2The high-temperature-resistant silver paste has good stability at high temperature, so that the problem of thermal stability of a passivation layer is solved, expensive low-temperature silver paste is not required to be used in the subsequent process, and the production cost is greatly reduced.
In the application, the N-type monocrystalline silicon wafer is used as a light absorption layer, the resistivity is preferably 1-7 omega cm, and the minority carrier lifetime is preferably more than 1000 microseconds.
Furthermore, the thickness of the silicon dioxide tunnel passivation layer can be 5-10nm, so that defects on the surface of the N-type monocrystalline silicon wafer can be passivated, and a tunnel heterojunction can be formed to ensure the collection of charges. In the step (1), a silicon dioxide tunnel passivation layer may be formed on the N-type single crystal silicon wafer by using a plasma oxidation Process (PO). Compared with other modes (such as LPCVD, thermal oxidation, ozonization and the like), the method for forming the passivation layer by adopting the plasma oxidation mode has the advantages of low reaction temperature, high control precision of the thickness of the passivation layer, high reaction speed, good compactness of the passivation layer and the like.
Furthermore, the present application also provides the main process parameters for forming the passivation layer by using the plasma oxidation method: the power supply frequency is set to 2.45GHz, the pressure is set to 0.1-50mbar, Te (electron temperature) is 1-5eV, Ti (ion temperature) < 0.5eV, ne (electron density) is 10 eV9-1012/cm3Ionization rate is 0.1-1%.
(2) And forming an N-type polycrystalline silicon carbide (SiC) layer with a wide band gap on the front surface of the N-type monocrystalline silicon wafer.
In this step, a conventional amorphous silicon layer is replaced with a wide-bandgap N-type polycrystalline SiC layer, which functions as a window layer and an electron transport layer. The N-type polycrystalline SiC layer with the wide band gap has higher visible light transmittance and conductivity compared with the amorphous silicon layer, so that the polycrystalline SiC film is used as the window layer, and the collection effect of the heterojunction solar cell on photo-generated electrons can be greatly improved.
Furthermore, the thickness of the N-type polycrystalline SiC layer with the wide band gap can be 10-20nm, so that the requirement for building a built-in electric field of a PN junction of the heterojunction solar cell is met, and the loss of incident photons caused by the fact that the polycrystalline SiC layer is too thick can be avoided.
In the step (2), preferably, an N-type polycrystalline silicon carbide layer with a wide band gap is formed on the front surface of the N-type monocrystalline silicon wafer by adopting a medium-frequency magnetron sputtering method. The component of the N-type polycrystalline SiC layer with the wide band gap is N or P element doped polycrystalline SiC, and the N-type polycrystalline SiC layer with the wide band gap prepared by the medium-frequency magnetron sputtering process has the advantages of high crystallinity, adjustable doping, no plating around phenomenon, high conductivity, high visible light transmittance and the like, so that the absorption efficiency of the heterojunction solar cell on blue light, the absorption efficiency on incident light and the collection effect of photo-generated charges can be improved.
Specifically, the front side of an N-type monocrystalline silicon wafer is subjected to intermediate frequency magnetron sputtering process and SiH4、PH3、CH4As process gas or as SiH4、NH3、CH4An N-type polycrystalline SiC layer with a wide band gap of 10-20nm in thickness is prepared as a process gas. Furthermore, the application also provides main process parameters of forming the wide-band-gap N-type polycrystalline silicon carbide layer on the front surface of the N-type monocrystalline silicon wafer by adopting a medium-frequency magnetron sputtering mode: the temperature is set to 200 deg.C, the power frequency is set to 40KHz, the power is set to 1500W, the pressure is set to 0.1-50mbar, and SiH is used4、PH3、CH4As process gas, SiH4、PH3、CH4The process gas flow ratio of (1) is Si: c: p =1:1.2:0.05, or in SiH4、NH3、CH4As process gas, SiH4、NH3、CH4The process gas flow ratio of (1) is Si: c: n =1:1.2:0.05, preparedThe band gap width of the N-type polycrystalline SiC layer with wide band gap is 3-4.4eV, and the mobility is 1-10cm2V.s) doping concentration of 1017-1019/cm3。
(3) And forming a P-type polycrystalline silicon layer on the reverse side of the N-type monocrystalline silicon wafer.
In this step, a P-type polycrystalline silicon layer, which functions as a hole transport layer, is used instead of the conventional amorphous silicon layer. The P-type polycrystalline silicon layer has higher conductivity compared with the amorphous silicon layer, so that the collection effect of the heterojunction solar cell on the photogenerated holes can be greatly improved by adopting the P-type polycrystalline silicon film as the hole transport layer.
Further, the thickness of the P-type polycrystalline silicon layer can be 10-20nm, so that the requirement of building a built-in electric field of a PN junction of the heterojunction solar cell can be met.
In the step (3), preferably, a P-type polysilicon layer is formed on the reverse side of the N-type monocrystalline silicon wafer by adopting a medium-frequency magnetron sputtering mode. The P-type polycrystalline silicon layer is prepared by adopting a medium-frequency magnetron sputtering process, has the advantages of high crystallinity, adjustable doping, no plating winding phenomenon, high conductivity and the like, and can improve the collection effect of the heterojunction solar cell on photo-generated charges.
Specifically, the reverse side of an N-type monocrystalline silicon wafer is subjected to intermediate frequency magnetron sputtering process and SiH4、BH3Or with SiH4、B2H6Is used as process gas to prepare a P-type polycrystalline silicon layer with the thickness of 10-20 nm. Furthermore, the application also provides main process parameters for forming the P-type polycrystalline silicon layer on the reverse side of the N-type monocrystalline silicon wafer by adopting a medium-frequency magnetron sputtering mode: the temperature is set to 200 deg.C, the power frequency is set to 40KHz, the power is set to 1500W, the pressure is set to 0.1-50mbar, and SiH is used4、BH3As process gas, SiH4、BH3With a process gas flow ratio of Si: B =1:0.05, or with SiH4、B2H6As process gas, SiH4、B2H6The process gas flow ratio of (1) to (0.05) is Si: B =1:1, and the mobility of the prepared P-type polycrystalline silicon layer is 1-10cm2V.s, dopingImpurity concentration of 1017-1019/cm3。
(4) Boron-doped zinc oxide layers (ZnO: B, BZO) are respectively formed on the front surface and the back surface of the N-type monocrystalline silicon wafer.
In the step, the boron-doped zinc oxide layer is adopted to replace the traditional ITO as the TCO electrode, and the ZnO can form a crystal pyramid structure in the film forming process to realize the scattering of incident light and improve the sunlight absorption effect of the heterojunction solar cell.
Furthermore, the thickness of the boron-doped zinc oxide layer can be 100-500 nm, so that both optical and electrical properties can be considered, the square resistance of the boron-doped zinc oxide layer is less than 20 omega, and the visible light transmittance is more than 85%.
In the step (4), a boron-doped zinc oxide layer is preferably formed on the front surface and the back surface of the N-type monocrystalline silicon wafer respectively by means of LPCVD (low pressure chemical vapor deposition). The BZO prepared by the LPCVD process replaces ITO to be used as a TCO electrode, and the advantages are embodied in four aspects: firstly, the damage of a passivation layer caused by using a PVD process can be avoided, and the surface passivation effect is improved; secondly, rare metal In is avoided, so that the production cost can be greatly reduced; thirdly, the LPCVD procedure can realize simultaneous film coating of the front side and the back side, thereby improving the production efficiency and greatly reducing the equipment cost; finally, the ZnO forms a pyramid crystal structure in the film forming process, so that the scattering of incident light can be realized, and the photoelectric response efficiency of the solar cell is improved.
Furthermore, the application also provides main process parameters for forming the boron-doped zinc oxide layer on the front surface and the back surface of the N-type monocrystalline silicon wafer respectively by adopting an LPCVD mode: setting the temperature at 200 deg.C and the pressure at 0.1-50mbar, using water vapor and diethyl zinc (C)4H10Zn), diborane (B)2H6) The flow ratio of diethyl zinc to diborane was Zn: B =1:0.05 as process gas.
(5) And forming metal electrodes on the boron-doped zinc oxide layers on the front surface and the back surface of the N-type monocrystalline silicon wafer.
The metal electrode is used for collecting photo-generated current, and can be a silver (Ag) electrode. In the step (5), a metal electrode may be formed on the boron-doped zinc oxide layer by means of screen printing.
According to the preparation method of the heterojunction solar cell, the wide-band-gap N-type polycrystalline silicon carbide layer serves as the window layer and the electron transmission layer, the P-type polycrystalline silicon layer serves as the hole transmission layer, and the BZO serves as the TCO electrode through the cell structure and the optimization process, so that the heterojunction solar cell does not need a texturing process, the pollution of metal ions to a cell piece and the treatment process of KOH waste liquid are avoided, the performance of the heterojunction solar cell is improved, and meanwhile the production cost is reduced. Meanwhile, SiO with good thermal stability is adopted2The passivation layer replaces amorphous silicon, so that expensive low-temperature silver paste can be avoided, and the production cost is greatly reduced; the N-type polycrystalline silicon carbide layer with high visible light transmittance and high conductivity and wide band gap is used as the window layer and the electron transmission layer, so that the collection efficiency of the heterojunction solar cell on photo-generated electrons can be greatly improved; the P-type polycrystalline silicon layer is adopted as the hole transport layer, so that the collection efficiency of the heterojunction solar cell on the photogenerated holes can be greatly improved; by adopting BZO to replace ITO as the TCO electrode, rare metal In can be avoided, the production cost is greatly reduced, moreover, the ZnO forms a pyramid crystal structure In the film forming process, so that the scattering of incident light can be realized, and the photoelectric response efficiency of the heterojunction solar cell can be improved.
The present application also provides a heterojunction solar cell, as shown in fig. 2, comprising an N-type monocrystalline silicon wafer 11;
a silicon dioxide tunnel passivation layer 12, a wide-band-gap N-type polycrystalline silicon carbide layer 13, a boron-doped zinc oxide layer 15 and a metal electrode 16 are sequentially arranged on the front surface of the N-type monocrystalline silicon wafer 11 from inside to outside;
a silicon dioxide tunnel passivation layer 12, a P-type polycrystalline silicon layer 14, a boron-doped zinc oxide layer 15 and a metal electrode 16 are sequentially arranged on the reverse side of the N-type monocrystalline silicon wafer from inside to outside.
The present application is further illustrated by the following specific examples.
Example 1
(1) Selecting an N-type monocrystalline silicon wafer as a substrate, wherein the thickness of the N-type monocrystalline silicon wafer is 150 mu m, and the size of the N-type monocrystalline silicon wafer is 182 x 182mm2The resistivity is 1 to 7 omega cm,the minority carrier lifetime is more than 1000 mus, and the N-type monocrystalline silicon wafer is cleaned and polished.
(2) Carrying out oxidation treatment on the front side and the back side of the N-type monocrystalline silicon wafer by adopting a plasma oxidation process, respectively forming a silicon dioxide tunnel passivation layer with the thickness of 5nm on the front side and the back side of the N-type monocrystalline silicon wafer, and forming main process parameters of the passivation layer in a plasma oxidation mode: the power frequency was set at 2.45GHz, the pressure was set at 50mbar, the electron temperature was 3eV, the ion temperature was 0.3eV, and the electron density was 10 eV10/cm3The ionization rate was 1%.
(3) Adopting medium frequency magnetron sputtering process on the front surface of the N-type monocrystalline silicon wafer, and using H2、SiH4、PH3、CH4The N-type polycrystalline silicon carbide layer with the wide band gap and the thickness of 15nm is prepared as process gas, and the main process parameters of the N-type polycrystalline silicon carbide layer with the wide band gap formed by the medium-frequency magnetron sputtering process are as follows: the temperature was set to 200 deg.C, the power frequency was set to 40KHz, the power was set to 1500W, the pressure was set to 50mbar, SiH4、CH4、PH3The process gas flow ratio of (1) is Si: C: P =1:1.2: 0.05.
(4) The reverse side of the N-type monocrystalline silicon wafer is subjected to a medium-frequency magnetron sputtering process and H2、SiH4、BH3The main process parameters of forming the P-type polycrystalline silicon layer by the medium-frequency magnetron sputtering process are as follows: the temperature was set to 200 deg.C, the power frequency was set to 40KHz, the power was set to 1500W, the pressure was set to 50mbar, SiH4、BH3The process gas flow ratio of (a) is Si: B =1: 0.05.
(5) Respectively forming boron-doped zinc oxide layers with the thickness of 500nm on the front surface and the back surface of the N-type monocrystalline silicon wafer by adopting an LPCVD (low pressure chemical vapor deposition) process, and forming the boron-doped zinc oxide layers on the N-type monocrystalline silicon wafer by adopting an LPCVD mode, wherein the main process parameters are as follows: the temperature is set to 200 ℃, the pressure is set to 50mbar, water vapor, diethyl zinc and diborane are used as process gases, and the flow ratio of the process gases of the diethyl zinc and the diborane is Zn: B =1: 0.05.
(6) And forming Ag electrodes on the boron-doped zinc oxide layers on the front surface and the back surface of the N-type monocrystalline silicon wafer.
The results of comparing the measured data of the electrical properties of the heterojunction solar cell prepared in example 1 with the properties of the conventional heterojunction solar cell are shown in table 1, wherein the structure of the conventional heterojunction solar cell is shown in fig. 1, and an intrinsic hydrogen-rich amorphous silicon layer 2 (N-Si) with a thickness of 5nm, an N-type doped layer 3 (a-Si: H) with a thickness of 10nm, a P-type doped layer 4 with a thickness of 10nm, and a transparent conductive layer (TCO) 5 with a thickness of 50nm are disposed on the surface of an N-type silicon wafer 1 subjected to a KOH texturing process. As can be seen from the data in Table 1, the performance of the heterojunction solar cell prepared by the scheme of the embodiment of the application is superior to that of the traditional heterojunction solar cell, and the preparation cost is greatly lower than that of the traditional process through the improvement of the process.
TABLE 1
| Short circuit current (mA/cm)2） | Open circuit voltage (mV) | Fill factor | Conversion efficiency | |
| Conventional HJT | 38 | 660 | 0.78 | 19.56 |
| Example 1 | 35 | 705 | 0.81 | 21.26 |
It should be understood that the application of the present application is not limited to the above examples, and that modifications or changes may be made by those skilled in the art based on the above description, and all such modifications and changes are intended to fall within the scope of the appended claims.
Claims (10)
1. A preparation method of a heterojunction solar cell is characterized by comprising the following steps:
(1) taking an N-type monocrystalline silicon wafer as a substrate, and respectively forming a silicon dioxide tunnel passivation layer on the front side and the back side of the N-type monocrystalline silicon wafer;
(2) forming an N-type polycrystalline silicon carbide layer with a wide band gap on the front surface of the N-type monocrystalline silicon wafer;
(3) forming a P-type polycrystalline silicon layer on the reverse side of the N-type monocrystalline silicon wafer;
(4) respectively forming boron-doped zinc oxide layers on the front side and the back side of the N-type monocrystalline silicon wafer;
(5) and forming metal electrodes on the boron-doped zinc oxide layers on the front surface and the back surface of the N-type monocrystalline silicon wafer.
2. The method of claim 1, wherein the thickness of the silicon dioxide tunnel passivation layer is 5-10 nm.
3. The method of claim 2, wherein the silicon dioxide tunnel passivation layer is formed by plasma oxidation, the power frequency is set to 2.45GHz, the pressure is set to 0.1-50mbar, the electron temperature is 1-5eV, the ion temperature is less than 0.5eV, and the electron density is 10 eV9-1012/cm3The ionization rate is 0.1-1%.
4. The method of claim 1, wherein the wide band gap N-type polycrystalline silicon carbide layer has a thickness of 10-20 nm.
5. The method of claim 4, wherein the wide band gap N-type polycrystalline silicon carbide layer is formed by medium frequency magnetron sputtering at 200 deg.C with a power frequency of 40KHz, a power of 1500W, and a pressure of 0.1-50mbar in SiH4、PH3、CH4As a process gas, the SiH4、PH3、CH4The process gas flow ratio of (1) is Si: c: p =1:1.2:0.05, or in SiH4、NH3、CH4As a process gas, the SiH4、NH3、CH4The process gas flow ratio of (1) is Si: c: n =1:1.2: 0.05; the band gap width of the wide band gap N-type polycrystalline silicon carbide layer is 3-4.4eV, and the mobility is 1-10cm2V.s) doping concentration of 1017-1019/cm3。
6. The method of claim 1, wherein the P-type polysilicon layer has a thickness of 10-20 nm.
7. The method of claim 6, wherein the P-type polysilicon layer is formed by magnetron sputtering at a medium frequency at 200 deg.C under a power frequency of 40KHz and a power of 1500W under a pressure of 0.1-50mbar in SiH4、BH3As a process gas, the SiH4、BH3With a process gas flow ratio of Si: B =1:0.05, or with SiH4、B2H6As a process gas, the SiH4、B2H6The process gas flow ratio of (1) is Si: B =1: 0.05; the mobility of the P-type polycrystalline silicon layer is 1-10cm2V.s) doping concentration of 1017-1019/cm3。
8. The method of claim 1, wherein the boron-doped zinc oxide layer has a thickness of 100-500 nm.
9. The method for preparing a heterojunction solar cell of claim 8, wherein the boron-doped zinc oxide layer is formed by low-pressure chemical vapor deposition, the temperature is set to 200 ℃, the pressure is set to 50mbar, water vapor, diethyl zinc and diborane are used as process gases, and the flow ratio of the process gases of the diethyl zinc and the diborane is Zn: B =1: 0.05; the square resistance of the boron-doped zinc oxide layer is less than 20 omega, and the visible light transmittance is more than 85 percent.
10. A heterojunction solar cell, which is prepared by the preparation method of the heterojunction solar cell as claimed in any one of claims 1 to 9, wherein the heterojunction solar cell comprises an N-type monocrystalline silicon wafer;
a silicon dioxide tunnel passivation layer, a wide-band-gap N-type polycrystalline silicon carbide layer, a boron-doped zinc oxide layer and a metal electrode are sequentially arranged on the front surface of the N-type monocrystalline silicon wafer from inside to outside;
and a silicon dioxide tunnel passivation layer, a P-type polycrystalline silicon layer, a boron-doped zinc oxide layer and a metal electrode are sequentially arranged on the reverse side of the N-type monocrystalline silicon wafer from inside to outside.
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| CN102460715A (en) * | 2009-04-21 | 2012-05-16 | 泰特拉桑有限公司 | High-efficiency solar cell structures and methods of manufacture |
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