CN108231928A - A kind of HJT hetero-junction solar cells and its multi-layer transparent electroconductive film - Google Patents

Abstract

A multi-layer transparent conductive film and a preparation method thereof, the multi-layer transparent conductive film comprises at least two layers of superimposed transparent conductive films, at least two layers of transparent conductive films are ITO films, the tin of the first layer of ITO film The dosing amount is 10-15% by weight, and the tin dosing amount of the second layer of ITO film is more than 5% by weight and <10% by weight; the preparation method comprises: continuously preparing a multi-layer ITO film under vacuum conditions, and During the transition process between one layer of ITO film and another layer of ITO film, the vacuum state is maintained. The present application also provides a HJT heterojunction battery comprising the above-mentioned multi-layer transparent conductive film. The photoelectric performance of the multi-layer transparent conductive thin film of the application is good, matching with the work function of the p-type and n-type amorphous silicon layers; various performance indexes of the HJT battery have been improved.

Description

A kind of HJT heterojunction battery and its multilayer transparent conductive film

technical field

The present application relates to but not limited to the technical field of solar cell technology, and particularly relates to but not limited to a HJT heterojunction cell and its multilayer transparent conductive film.

Background technique

The heterojunction amorphous silicon/crystalline silicon solar cell HJT (Hetero-junction with Intrinsic Thinlayer, referred to as HJT) is currently the mainstream high-efficiency solar cell. Its basic structure is usually shown in Figure 1, including 1: crystalline silicon; 2: intrinsic amorphous silicon layer; 3: p-type amorphous silicon layer; 4: n-type amorphous silicon layer; 5: transparent conductive film layer; 6: Front grid line; 7: Back grid line.

Indium Oxide doped Tin Film (ITO for short) is widely used in the transparent conductive film layer of HJT solar cells due to its excellent physical properties such as low resistivity and high visible light transmittance.

ITO acts as a conductive and anti-reflection film in HJT cells. The widely used ITO is a single-layer film. As an anti-reflection coating, the traditional 1/4 wavelength single-layer ITO film has a good anti-reflection effect only for small-angle incidents of specific wavelengths. In order to better meet the anti-reflection requirements of HJT batteries, multi-layer anti-reflection coatings came into being.

Contents of the invention

The following is an overview of the topics described in detail in this article. This summary is not intended to limit the scope of the claims.

The application provides a multilayer transparent conductive film capable of improving the performance of HJT solar cells.

Specifically, the application provides a multilayer transparent conductive film, the multilayer transparent conductive film includes at least two layers of transparent conductive films, at least two layers of transparent conductive films are ITO films, and the first layer of ITO film The doping amount of tin is 10-15% by weight, and the doping amount of tin in the second layer of ITO film is ≥5% by weight and <10% by weight.

In some embodiments, the multilayer transparent conductive film may also include a third layer of ITO film, the first layer of ITO film, the second layer of ITO film and the third layer of ITO film are arranged in sequence, so The content of tin in the third layer of ITO film can be ≥ 1% by weight and < 5% by weight, or 10-15% by weight.

In some embodiments, the tin content of the first layer of ITO film can be 10% by weight, the tin content of the second layer of ITO film can be 5% by weight, and the tin content of the third layer of ITO film The amount of tin added can be 3% by weight.

In some embodiments, the multilayer transparent conductive film may also include a fourth layer of ITO film, the first layer of ITO film, the second layer of ITO film, the third layer of ITO film and the fourth layer of ITO film. Layers of ITO thin films are arranged in sequence, and the doping amount of tin in the fourth layer of ITO thin films can be 10-15% by weight.

In some embodiments, the tin content of the first layer of ITO film can be 10% by weight, the tin content of the second layer of ITO film can be 5% by weight, and the tin content of the third layer of ITO film The doping amount of tin may be 3% by weight, and the doping amount of tin in the fourth layer of ITO thin film may be 10% by weight.

In some embodiments, the thickness of each layer of ITO film can be in the range of 15-50 nm.

In some embodiments, the refractive index n of each layer of ITO film can be in the range of 1.8-2.0, the band gap can be in the range of 3.0-4.6eV, and the carrier concentration can be in the range of (1-10)×10 In the range of ²⁰ cm ^-3 , the carrier mobility can be in the range of 10-50 cm ² /vs.

The present application also provides a method for preparing the multilayer transparent conductive film as described above, the method comprising: continuously preparing a multilayer ITO film under vacuum conditions, and during the transition process between one layer of ITO film and another layer of ITO film , to maintain a vacuum state.

In some embodiments, the step of continuously preparing a multilayer ITO thin film under vacuum conditions may be: using magnetron sputtering to continuously prepare a multilayer ITO thin film under vacuum conditions;

In some embodiments, the step of continuously preparing a multilayer ITO thin film under vacuum conditions may be: using a magnetron sputtering method to continuously prepare a multilayer ITO thin film under vacuum conditions, wherein the gas used in the magnetron sputtering method It can be a mixture of oxygen and argon, and the volume flow ratio of oxygen and argon can be 0-3:97, the sputtering power can be 2-8kW, and the background vacuum degree of the chamber used in the preparation process can be controlled In the range of ≥5×10 ^-4 Pa.

The present application also provides a HJT heterojunction battery, the HJT battery includes the above-mentioned multi-layer transparent conductive film.

In some embodiments, one side of the HJT heterojunction cell may include at least two stacked transparent conductive films, and the other side may include at least three stacked transparent conductive films.

In some embodiments, the HJT heterojunction cell can also include a crystalline silicon layer (1), an intrinsic amorphous silicon layer (2), a first amorphous silicon layer (3), a second amorphous silicon layer ( 4) and gate lines (6, 7), the crystalline silicon layer (1) has a first surface and a second surface;

One side of the HJT heterojunction cell can include a multilayer transparent conductive film (5), and the other side can include a multilayer transparent conductive film (5'), and the multilayer transparent conductive film (5) can be provided with four layers of transparent conductive films. A conductive film, the multi-layer transparent conductive film (5') can be provided with three layers of transparent conductive films;

The intrinsic amorphous silicon layer (2), the second amorphous silicon layer (4), the fourth layer of ITO film (5-4) of the multilayer transparent conductive film (5), the third layer of ITO The film (5-3), the second layer of ITO film (5-2), the first layer of ITO film (5-1) and the gate line 6 can be arranged on the crystalline silicon layer in sequence from inside to outside (1) on the first surface;

The intrinsic amorphous silicon layer (2), the first amorphous silicon layer (3), the third layer ITO film (5-3') of the multilayer transparent conductive film (5'), the second The first layer of ITO film (5-2'), the first layer of ITO film (5-1') and the gate line 7 can be sequentially arranged on the second surface of the crystalline silicon layer (1) from inside to outside superior.

In some embodiments, the doping amount of tin in the first layer of ITO film (5-1) of the multilayer transparent conductive film (5) can be 10% by weight, and the tin in the second layer of ITO film (5-2) The dosage of tin can be 5% by weight, the dosage of tin in the third layer of ITO film (5-3) can be 3% by weight, and the dosage of tin in the fourth layer of ITO film (5-4) can be 10% by weight ;

The doping amount of tin in the first layer of ITO film (5-1') of the multilayer transparent conductive film (5') can be 10% by weight, and the doping amount of tin in the second layer of ITO film (5-2') It can be 5% by weight, and the tin content of the third layer of ITO thin film (5-3') can be 3% by weight.

In some embodiments, the crystalline silicon layer (1) may be an n-type crystalline silicon layer.

In some embodiments, the first amorphous silicon layer (3) may be a p-type amorphous silicon layer, and the second amorphous silicon layer (4) may be an n-type amorphous silicon layer.

The inventors of the present application found that the photoelectric performance of the ITO film, such as the matching of the refractive index and work function with the p-type amorphous silicon layer and the n-type amorphous silicon layer, directly affects the performance of the HJT battery. The present application gradually changes the doping amount of tin in ITO to form a multi-layer stepped ITO anti-reflection film, thereby improving the photoelectric performance of the ITO film. Compared with single-layer ITO, the advantage of the multi-layer stepped ITO thin film of this application is to further reduce the loss of light through the multi-layer stepped ITO structure, and at the same time, through the optimized ITO thin film and p, n-type amorphous silicon The work function of the layer is matched, so that the ITO in contact with the n-type amorphous silicon layer has a relatively low work function, and the ITO in contact with the p-type amorphous silicon layer has a relatively high work function, which ultimately improves the performance of the HJT battery. Performance.

Additional features and advantages of the application will be set forth in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solution of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical solution of the present application, and do not constitute a limitation to the technical solution of the present application.

Figure 1 is a schematic diagram of the structure of a traditional HJT heterojunction cell.

FIG. 2 is a schematic structural view of the HJT heterojunction battery according to Example 3 of the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the application clearer, the embodiments of the application will be described in detail below in conjunction with the accompanying drawings. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

Example 1

A multi-layer transparent conductive film 5, comprising four layers of stacked ITO films, sequentially the first layer of ITO film 5-1, the second layer of ITO film 5-2, the third layer of ITO film 5-3, the fourth layer ITO thin film 5-4; Wherein, the dosing amount of the tin of described first layer ITO thin film 5-1 is 10 weight %, thickness is 34nm; The dosing amount of the tin of described second layer ITO thin film 5-2 is 5 weight % %, the thickness is 34nm; the tin content of the third layer of ITO film 5-3 is 3% by weight, and the thickness is 34nm; the tin content of the fourth layer of ITO film 5-4 is 10% by weight, The thickness is 10nm.

Prepare the multilayer transparent conductive film 5 according to the following method:

(1) select the substrate (a crystalline silicon wafer that has deposited two layers of intrinsic amorphous silicon layers and two layers of amorphous silicon layers);

(2) Adjust the vacuum degree of the vacuum chamber to 5×10 ^-4 Pa, feed oxygen and argon into the vacuum chamber according to the volume flow ratio of 2:98, and use the magnetron sputtering method at a sputtering power of 4kW Depositing the fourth layer of ITO thin film 5-4 on the first surface of the substrate;

(3) Maintain the vacuum degree of the vacuum chamber at 5×10 ^-4 Pa, feed oxygen and argon into the vacuum chamber according to the volume flow ratio of 5:95, and the sputtering power is 4kw, continue to spray in the vacuum chamber Depositing the third layer of ITO film 5-3;

(4) Maintain the vacuum degree of the vacuum chamber at 5 × 10 ^-4 Pa, feed oxygen and argon into the vacuum chamber according to the volume flow ratio of 6:94, and the sputtering power is 4kw, continue to spray in the vacuum chamber Depositing the second layer of ITO thin film 5-2;

(5) Maintain the vacuum degree of the vacuum chamber at 5×10 ^-4 Pa, pass oxygen and argon into the vacuum chamber according to the volume flow ratio of 2:98, and the sputtering power is 4kw, continue in the vacuum chamber Deposit the first layer of ITO thin film 5-1.

During the entire deposition process, the vacuum chamber is not opened, and the deposition is carried out continuously, and the vacuum cannot be broken.

Example 2

A multi-layer transparent conductive film 5', including three layers of ITO films, which are sequentially the first layer of ITO film 5-1', the second layer of ITO film 5-2', and the third layer of ITO film 5-3' , wherein, the tin doping amount of the first layer of ITO film 5-1' is 10% by weight, and the thickness is 37nm; the tin doping amount of the second layer of ITO film 5-2' is 5% by weight, and the thickness is 37nm; the doping amount of tin in the third layer of ITO thin film 5-3' is 3% by weight, and the thickness is 37nm.

According to the step (3)-(5) of preparing described multilayer transparent conductive film 5 in embodiment 1, continue to deposit the third layer of described multilayer transparent conductive film 5 ' on the second surface of the substrate of embodiment 1 ITO thin film 5-3', second layer ITO thin film 5-2' and first layer ITO thin film 5-1'.

Example 3

A kind of HJT heterojunction battery, its structure as shown in Figure 2, comprises n-type crystalline silicon layer 1, intrinsic amorphous silicon layer 2, p-type amorphous silicon layer 3, n-type amorphous silicon layer 4, embodiment The multilayer transparent conductive layer film 5 described in 1, the multilayer transparent conductive layer film 5' described in Embodiment 2, the front gate line 6 and the back gate line 7, the crystalline silicon layer 1 has a first surface and a second surface;

Define that the side where the n-type amorphous silicon layer 4 is located is the front side of the battery, and the side where the p-type amorphous silicon layer 3 is located is the back side of the battery;

The intrinsic amorphous silicon layer 2, the n-type amorphous silicon layer 4, the fourth layer ITO film 5-4 of the multilayer transparent conductive layer film 5 described in Embodiment 1, the third layer ITO film 5- 3. The second layer of ITO film 5-2, the first layer of ITO film 5-1 and the front gate line 6 are sequentially arranged on the first surface of the crystalline silicon layer 1 in order from inside to outside;

The intrinsic amorphous silicon layer 2, the p-type amorphous silicon layer 3, the third layer of ITO film 5-3' of the multilayer transparent conductive layer film 5' described in Embodiment 2, and the second layer of ITO film 5-2', the first layer of ITO thin film 5-1' and the back gate line 7 are sequentially arranged on the second surface of the crystalline silicon layer 1 from inside to outside.

Example 4

A HJT heterojunction battery. The difference between the HJT heterojunction battery in this embodiment and the heterojunction battery in Example 3 is only that:

The multilayer transparent conductive film 5 does not include the third layer of ITO film 5-3; the multilayer transparent conductive film 5' does not include the third layer of ITO film 5-3'.

Although the embodiments disclosed in the present application are as above, the content described is only the embodiments adopted to facilitate understanding of the present application, and is not intended to limit the present application. Anyone skilled in the field of this application can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in this application, but the scope of patent protection of this application must still be The scope defined by the appended claims shall prevail.

Claims (13)

1. a multilayer transparent conductive film, it is characterized in that, described multilayer transparent conductive film comprises at least two layers of superimposed transparent conductive films, at least two layers of transparent conductive films are ITO films, the first layer of ITO films The doping amount of tin is 10-15% by weight, and the doping amount of tin in the second layer of ITO film is ≥5% by weight and <10% by weight. 2. multilayer transparent conductive film according to claim 1, is characterized in that, also comprises the 3rd layer ITO film, described first layer ITO film, described second layer ITO film and described 3rd layer ITO film Set in sequence, the tin content of the third layer of ITO thin film is ≥1 wt% and <5 wt%, or 10-15 wt%. 3. multilayer transparent conductive film according to claim 2, is characterized in that, the dosing amount of the tin of described first layer ITO film is 10 weight %, the dosing amount of the tin of described second layer ITO film is 5. % by weight, the tin content of the third layer of ITO thin film is 3% by weight. 4. multilayer transparent conductive film according to claim 2, is characterized in that, also comprises the 4th layer ITO film, described first layer ITO film, described second layer ITO film, described 3rd layer ITO film and the fourth layer of ITO thin film are arranged sequentially, and the doping amount of tin in the fourth layer of ITO thin film is 10-15% by weight. 5. multilayer transparent conductive film according to claim 4, is characterized in that, the dosing amount of the tin of described first layer ITO film is 10 weight %, the dosing amount of the tin of described second layer ITO film is 5. % by weight, the amount of tin in the third layer of ITO film is 3% by weight, and the amount of tin in the fourth layer of ITO film is 10% by weight. 6. The multilayer transparent conductive film according to any one of claims 1-5, characterized in that the thickness of each layer of ITO film is in the range of 15-50 nm. 7. The multilayer transparent conductive film according to any one of claims 1-6, characterized in that, the refractive index n of each layer of ITO film is in the range of 1.8-2.0, and the band gap is at 3.0-4.6eV In the range of , the carrier concentration is in the range of (1-10)×10 ²⁰ cm ^-3 , and the carrier mobility is in the range of 10-50 cm ² /vs. 8. A method for preparing the multilayer transparent conductive film according to any one of claims 1-7, wherein the method comprises: continuously preparing a multilayer ITO film under vacuum conditions, and in one layer During the transition process between the ITO film and another layer of ITO film, maintain the vacuum state; The step of continuously preparing a multilayer ITO thin film under vacuum conditions is selected from any one of the following modes: using magnetron sputtering to continuously prepare multilayer ITO thin films under vacuum conditions; or Adopt magnetron sputtering method to prepare multilayer ITO film continuously under vacuum condition, wherein, the gas that described magnetron sputtering method adopts is the mixed gas of oxygen and argon, and the volume flow ratio of oxygen and argon is 0- 3:97, the sputtering power is 2-8kW, and the background vacuum degree of the chamber used in the preparation process is controlled within the range of ≥5×10 ^-4 Pa. 9. A HJT heterojunction battery, characterized in that the HJT battery comprises the multilayer transparent conductive film according to any one of claims 1-8. 10. The HJT heterojunction battery according to claim 9, wherein one side of the HJT heterojunction battery includes at least two layers of stacked transparent conductive films, and the other side includes at least three layers of stacked transparent conductive films. 11. The HJT heterojunction battery according to claim 10, characterized in that, the HJT heterojunction battery further comprises a crystalline silicon layer (1), an intrinsic amorphous silicon layer (2), a first amorphous silicon a layer (3), a second amorphous silicon layer (4) and gate lines (6, 7), the crystalline silicon layer (1) having a first surface and a second surface; One side of the HJT heterojunction battery includes a multi-layer transparent conductive film (5), and the other side includes a multi-layer transparent conductive film (5'), and the multi-layer transparent conductive film (5) is provided with four layers of transparent conductive films, The multi-layer transparent conductive film (5') is provided with three layers of transparent conductive films; The intrinsic amorphous silicon layer (2), the second amorphous silicon layer (4), the fourth layer of ITO film (5-4) of the multilayer transparent conductive film (5), the third layer of ITO The thin film (5-3), the second layer of ITO thin film (5-2), the first layer of ITO thin film (5-1) and the gate line 6 are sequentially arranged on the crystalline silicon layer ( 1) on the first surface; The intrinsic amorphous silicon layer (2), the first amorphous silicon layer (3), the third layer ITO film (5-3') of the multilayer transparent conductive film (5'), the second A layer of ITO thin film (5-2'), a first layer of ITO thin film (5-1') and the gate line 7 are sequentially arranged on the second surface of the crystalline silicon layer (1) from inside to outside . 12. HJT heterojunction battery according to claim 11, is characterized in that, the doping amount of the tin of the first layer ITO film (5-1) of described multilayer transparent conductive film (5) is 10 weight %, The tin content of the second layer of ITO film (5-2) is 5% by weight, the tin content of the third layer of ITO film (5-3) is 3% by weight, the fourth layer of ITO film (5-4) The dosage of tin is 10% by weight; The dosing amount of the tin of the first layer ITO film (5-1 ') of described multilayer transparent conductive film (5 ') is 10 weight %, the dosing amount of the tin of the second layer ITO film (5-2 ') is 5% by weight, and the doping amount of tin in the third layer of ITO thin film (5-3') is 3% by weight. 13. The HJT heterojunction battery according to claim 11 or 12, characterized in that the crystalline silicon layer (1) is an n-type crystalline silicon layer; The first amorphous silicon layer (3) is a p-type amorphous silicon layer, and the second amorphous silicon layer (4) is an n-type amorphous silicon layer.