CN115295684B - A kind of preparation method of photovoltaic absorption layer thin film of copper antimony selenium solar cell - Google Patents

Abstract

The invention discloses a preparation method of a photovoltaic absorption layer film of a copper antimony selenium solar cell, which comprises the steps of sequentially depositing antimony selenide and cuprous selenide double-layer prefabricated layers by a radio frequency magnetron sputtering method, and respectively controlling sputtering power and deposition time to adjust the thicknesses of the antimony selenide and cuprous selenide prefabricated layers to ensure that the components of the antimony selenide and cuprous selenide prefabricated layers are rich in antimony; and then carrying out vacuum annealing to ensure that the cuprous selenide and the antimony selenide in the prefabricated layer fully react to generate the copper antimony selenium, and improving the crystallinity to finally generate the copper antimony selenium film with good crystallinity. The preparation method is suitable for producing large-area solar cells in a flow line due to the adoption of a magnetron sputtering sequential deposition process, and the production process is clean and environment-friendly, so that a feasible way is explored for industrialization of the copper antimony selenium thin-film solar cells.

Description

A kind of preparation method of photovoltaic absorption layer thin film of copper antimony selenium solar cell

technical field

The invention relates to a method for preparing a thin film of an absorbing layer of a solar cell, in particular to a method for preparing a thin film of a photovoltaic absorbing layer of a copper-antimony-selenium solar cell.

Background technique

With the increasingly severe energy crisis in human society, the development of an efficient and clean photovoltaic industry has become an important trend. In recent years, thin-film solar cells with CdTe and CIGS as absorber layers have been intensively studied and successfully commercialized. However, due to the toxicity of Cd and the scarcity of Ga and In elements, the development of thin-film photovoltaic industry is limited, and it is urgent to develop new thin-film materials. Copper antimony selenium (CuSbSe ₂ ), as one of them, is attracting the attention of the industry. Copper antimony selenium (CuSbSe ₂ ) film is rich in elements in the earth's crust, safe and non-toxic, and the film has a high light absorption coefficient and a good band gap. The solar cell using it as the absorbing layer has a theoretical photoelectric conversion efficiency of up to 27%, in addition, copper antimony selenium (CuSbSe ₂ ) has a low melting point (~480 °C), which is very suitable for the manufacture of flexible solar cells, so it has great development potential.

Regarding the preparation of copper antimony selenium (CuSbSe ₂ ) light-absorbing layer, there are not many methods reported in the literature, mainly solution method and pulsed laser deposition method. These two methods have high production costs and are not suitable for the growth of large-area thin films. limit large-scale production. The magnetron sputtering method has high production efficiency, environmentally friendly production process, stable coating process and good repeatability, and is suitable for large-scale assembly line production. At present, there are reports in the literature that copper antimony selenium (CuSbSe ₂ ) can be obtained by co-sputtering Sb ₂ Se ₃ and Cu ₂ Se double targets, but this method requires high-temperature heat treatment on the substrate while sputtering, co-sputtering and sputtering Due to the complex process and high technical difficulty of high-temperature heat treatment, it is not suitable for large-scale production on the assembly line. However, the sequential sputtering of Sb ₂ Se ₃ and Cu ₂ Se is used to prepare a pre-selenide film at room temperature, and then anneal to obtain a copper antimony selenium (CuSbSe ₂ ) film. This two-step process reduces technical difficulty and improves It improves the stability of the coating process, so it is suitable for assembly line production.

Contents of the invention

The invention aims to provide a method for preparing a photovoltaic absorbing layer film of a copper-antimony-selenium solar cell, so as to obtain a copper-antimony-selenium (CuSbSe ₂ ) film with good crystallinity. The invention adopts the radio frequency magnetron sputtering method to sequentially deposit antimony selenide and cuprous selenide double-layer prefabricated layers, respectively controls the sputtering power and deposition time to adjust the thickness of the antimony selenide and cuprous selenide prefabricated layers, so that its composition is rich Antimony; followed by vacuum annealing, so that the cuprous selenide and antimony selenide in the prefabricated layer fully react to form copper antimony selenide, and improve the crystallinity, finally forming a copper antimony selenide film with good crystallinity. Since the preparation method of the invention uses a magnetron sputtering sequential deposition process, it is suitable for assembly line production of large-area solar cells, and the production process is clean and environmentally friendly, exploring a feasible way for the industrialization of copper antimony selenium thin film solar cells.

The preparation method of the copper antimony selenide thin film used for the solar cell absorbing layer of the present invention adopts the method of sequentially sputtering and depositing the selenide prefabricated layer and then annealing to prepare the copper antimony selenide thin film, and the selenide prefabricated layer is cuprous selenide and selenium antimony bilayer structure. Compared with the preparation of copper antimony selenium with metal prefabricated layer, since selenium element already exists in the selenide prefabricated layer, no selenization is required during later annealing, and the production process is cleaner and more environmentally friendly.

Include the following steps:

Step 1: Preparation of Selenide Prefabricated Layer

The FTO substrate was placed on the substrate tray of the magnetron sputtering coating system, and the vacuum was pumped to 5×10 ^-4 Pa, argon was passed through, and the Sb ₂ Se ₃ layer and the Cu ₂ Se layer were sequentially deposited by radio frequency magnetron sputtering layer, by controlling the sputtering power and deposition time of the two layers to control the ratio of Sb and Cu elements in the prefabricated layer to obtain an antimony-rich prefabricated layer;

Step 2: Annealing of Selenide Preformed Layer

Place the selenide prefabricated layer obtained in step 1 in a vacuum tube furnace, first evacuate, then raise the substrate to the target temperature for annealing, so that the Sb ₂ Se ₃ and Cu ₂ Se in the selenide prefabricated layer fully react and crystallization, and finally a copper antimony selenium (CuSbSe ₂ ) film is obtained.

specifically:

In step 1, place the FTO on the substrate tray in the vacuum chamber of the magnetron sputtering system, and evacuate to 5×10 ^-4 Pa, then pass in argon gas, and adjust the pressure of the vacuum chamber to 1.6 Pa; Controlled sputtering, sequential deposition of Sb ₂ Se ₃ layer and Cu ₂ Se layer. The sputtering power and sputtering time of Sb ₂ Se ₃ layers were 20-100W and 21 minutes respectively; the sputtering power and sputtering time of Cu ₂ Se layer were 20-80W and 9 minutes respectively. The distance between the target and the substrate is 3-5cm. The Sb:Cu (atomic ratio) was controlled within the range of 1.65-1.75:1 by adjusting the sputtering time and sputtering power of Sb ₂ Se ₃ and Cu ₂ Se.

In step 2, the selenide prefabricated layer is placed in a vacuum tube furnace for annealing. Vacuumize the quartz tube cavity of the dual temperature zone tube furnace first, and then anneal. The substrate temperature was raised from room temperature to the set annealing temperature of 380°C within 20 minutes, and then kept for 10 minutes, and the annealing was completed; after natural cooling to room temperature, a copper antimony selenium (CuSbSe ₂ ) film was obtained.

The invention adopts the radio frequency magnetron sputtering method to sequentially deposit antimony selenide and cuprous selenide double-layer prefabricated layers, respectively controls the sputtering power and deposition time to adjust the thickness of the antimony selenide and cuprous selenide prefabricated layers, so that its composition is rich Antimony; followed by vacuum annealing, so that the cuprous selenide and antimony selenide in the prefabricated layer fully react to form copper antimony selenide, and improve the crystallinity, finally forming a copper antimony selenide film with good crystallinity.

Because the preparation method of the invention uses a magnetron sputtering sequential deposition process, it is suitable for assembly line production of large-area solar cells, and the production process is clean and environmentally friendly, exploring a feasible way for the industrialization of copper antimony selenium thin film solar cells.

Description of drawings

Fig. 1 is the XRD spectrum of embodiment 1, 2, 3 sample film.

Fig. 2 is the Raman spectrum of embodiment 1, 2 sample film.

Detailed ways

The equipment used in the preparation of the selenide prefabricated layer by the magnetron sputtering method of the present invention is a high vacuum magnetron sputtering coating system, which is composed of mechanical pumps, molecular pumps, vacuum chambers, vacuum gauges, flow meters and other components, and is conventional equipment. The system can precisely control the cavity pressure by controlling the argon gas intake. The present invention uses a 500W radio frequency power supply. The device can precisely control the film thickness by changing the sputtering power and sputtering time. The targets used in the present invention are Sb ₂ Se ₃ targets and Cu ₂ Se targets. The prefabricated layer annealing process is completed in a vacuum tube furnace, which is composed of furnace wire, graphite sheet, thermocouple, insulation layer, quartz tube vacuum chamber, mechanical pump, gas system and other components. The device can adjust the crystallinity and phase of the film by setting the substrate temperature curve. The above-mentioned equipment or devices are conventional products and can be obtained commercially.

Example 1: Preparation of Copper Antimony Selenium (CuSbSe ₂ ) Solar Cell Light Absorbing Layer

1. Sonicate the FTO with deionized water, isopropanol, ethanol, and deionized water for 15 minutes, and then dry it with nitrogen;

2. Place the FTO substrate on the substrate tray of the magnetron sputtering coating system, adjust the distance between the Sb ₂ Se ₃ target and the substrate to 5cm, evacuate the chamber to 5×10 ^-4 Pa, and 32sccm argon gas, so that the pressure is 1.6Pa; use radio frequency magnetron sputtering to deposit the first layer of selenide prefabricated layer Sb ₂ Se ₃ layer, sputtering power 40W, sputtering time 21 minutes;

3. Use radio frequency magnetron sputtering to deposit the second selenide prefabricated layer Cu ₂ Se layer, the sputtering power is 40W, and the sputtering time is 9 minutes;

4. Put the selenide prefabricated layer Sb ₂ Se ₃ /Cu ₂ Se (Sb:Cu atomic ratio is 1.7:1) into a vacuum tube furnace for annealing; first vacuumize the quartz tube cavity of the dual temperature zone tube furnace , and then annealed. The substrate temperature of the selenide prefabricated layer rose from room temperature to 380° C. within 20 minutes, and was kept for 10 minutes. After the annealing was completed, the annealed sample film was obtained after natural cooling to room temperature.

Embodiment 2: in embodiment 1, the sputtering time of Cu ₂ Se is shortened to 8 minutes from 9 minutes, and other experimental conditions are unchanged

1. Sonicate the FTO with deionized water, isopropanol, ethanol, and deionized water for 15 minutes, and then dry it with nitrogen;

2. Place the FTO substrate on the substrate tray of the magnetron sputtering coating system, adjust the distance between the Sb ₂ Se ₃ target and the substrate to 5cm, evacuate the chamber to 5×10 ^-4 Pa, and 32sccm argon gas, so that the pressure is 1.6Pa, using radio frequency magnetron sputtering to deposit the first layer of selenide prefabricated layer Sb ₂ Se ₃ layer, sputtering power 40W, sputtering time 21 minutes;

3. Use radio frequency magnetron sputtering to deposit the second selenide prefabricated layer Cu ₂ Se layer, the sputtering power is 40W, and the sputtering time is 8 minutes;

4. Put the selenide prefabricated layer Sb ₂ Se ₃ /Cu ₂ Se (Sb:Cu atomic ratio is 1.9:1) into a vacuum tube furnace for annealing; first vacuumize the quartz tube cavity of the dual temperature zone tube furnace , and then annealed. The substrate temperature of the selenide prefabricated layer rose from room temperature to 380° C. within 20 minutes, and was kept for 10 minutes. After the annealing was completed, the annealed sample film was obtained after natural cooling to room temperature.

Embodiment 3: In embodiment 1, the sputtering time of Cu ₂ Se is shortened to 7 minutes from 9 minutes, and other experimental conditions are unchanged

1. Sonicate the FTO with deionized water, isopropanol, ethanol, and deionized water for 15 minutes, and then dry it with nitrogen;

2. Fix the FTO on the substrate with adhesive tape, install the Sb ₂ Se ₃ target first, adjust the distance between the target and the substrate to 5cm, close the cavity, and pump the background pressure inside the cavity with a mechanical pump and a molecular pump. To 5×10 ^-4 Pa, 32 sccm of argon gas was introduced to make the background pressure 1.6 Pa. Use radio frequency sputtering, sputtering power 40W, sputtering time 21 minutes;

3. Open the cavity, replace it with a Cu ₂ Se target, close the cavity, pump the background pressure inside the cavity to 5×10 ^-4 Pa with a mechanical pump and a molecular pump, and then inject 32 sccm argon gas to make the background pressure 1.6 Pa, use radio frequency sputtering, sputtering power is 40W, sputtering time is 7 minutes;

4. Put the selenide prefabricated layer Sb ₂ Se ₃ /Cu ₂ Se (Sb:Cu atomic ratio is 2.1:1) into a vacuum tube furnace for annealing; first vacuumize the quartz tube cavity of the dual temperature zone tube furnace , and then annealed. The substrate temperature of the selenide prefabricated layer rose from room temperature to 380° C. within 20 minutes, and was kept for 10 minutes. After the annealing was completed, the annealed sample film was obtained after natural cooling to room temperature.

Example 4: The annealing temperature in Example 1 is increased from 380°C to 400°C, and other experimental conditions remain unchanged

1. Sonicate the FTO with deionized water, isopropanol, ethanol, and deionized water for 15 minutes, and then dry it with nitrogen;

2. Place the FTO substrate on the substrate tray of the magnetron sputtering coating system, adjust the distance between the Sb ₂ Se ₃ target and the substrate to 5cm, evacuate the chamber to 5×10 ^-4 Pa, and 32sccm argon gas, so that the pressure is 1.6Pa; use radio frequency magnetron sputtering to deposit the first layer of selenide prefabricated layer Sb ₂ Se ₃ layer, sputtering power 40W, sputtering time 21 minutes;

3. Use radio frequency magnetron sputtering to deposit the second selenide prefabricated layer Cu ₂ Se layer, the sputtering power is 40W, and the sputtering time is 9 minutes;

4. Put the selenide prefabricated layer Sb ₂ Se ₃ /Cu ₂ Se (Sb:Cu atomic ratio is 1.7:1) into a vacuum tube furnace for annealing; first vacuumize the quartz tube cavity of the dual temperature zone tube furnace , and then annealed. The substrate temperature of the selenide prefabricated layer was raised from room temperature to 400° C. within 20 minutes, kept for 10 minutes, the annealing was completed, and the annealed sample film was obtained after natural cooling to room temperature.

Example 5: The annealing temperature in Example 1 is reduced from 380°C to 360°C, and other experimental conditions remain unchanged

1. Sonicate the FTO with deionized water, isopropanol, ethanol, and deionized water for 15 minutes, and then dry it with nitrogen;

2. Place the FTO substrate on the substrate tray of the magnetron sputtering coating system, adjust the distance between the Sb ₂ Se ₃ target and the substrate to 5cm, evacuate the chamber to 5×10 ^-4 Pa, and 32sccm argon gas, so that the pressure is 1.6Pa; use radio frequency magnetron sputtering to deposit the first layer of selenide prefabricated layer Sb ₂ Se ₃ layer, sputtering power 40W, sputtering time 21 minutes;

3. Use radio frequency magnetron sputtering to deposit the second selenide prefabricated layer Cu ₂ Se layer, the sputtering power is 40W, and the sputtering time is 9 minutes;

4. Put the selenide prefabricated layer Sb ₂ Se ₃ /Cu ₂ Se (Sb:Cu atomic ratio is 1.7:1) into a vacuum tube furnace for annealing; first vacuumize the quartz tube cavity of the dual temperature zone tube furnace , and then annealed. The substrate temperature of the selenide prefabricated layer was raised from room temperature to 360° C. within 20 minutes, and kept for 10 minutes. After the annealing was completed, the annealed sample film was obtained after natural cooling to room temperature.

FIG. 1 corresponds to the XRD spectrum of the sample film after annealing in Examples 1-3, and FIG. 2 corresponds to the Raman spectrum of the sample film after annealing in Examples 1 and 2. Firstly, the characterization of the sample of Example 1 was analyzed. It can be seen from XRD that the main peak (013) of CuSbSe ₂ in the sample of Example 1 is relatively sharp, indicating that its crystallinity is good. In the Raman spectrum of Fig. 2, the strongest peak 221 cm ^-1 of the sample of Example 1 also corresponds to the CuSbSe ₂ phase. No XRD and Raman peaks of the impurity phase were observed, indicating that the sample film of Example 1 was CuSbSe ₂ . Secondly, analyze the characterization of the sample of Example 2. It can be seen from Figure 1 that the strongest XRD peak of the sample of Example 2 is still the CuSbSe ₂ (013) peak, but the diffraction peak of the heterogeneous Sb ₂ Se ₃ appears. And in the Raman spectrum of Fig. 2, 198 cm ^-1 of the sample of Example 2 corresponds to Sb ₂ Se ₃ . It shows that the impurity phase Sb ₂ Se ₃ exists in Example 2. Finally, the characterization of the sample in Example 3 was analyzed. In the XRD pattern of the sample in Example 3, the XRD peak of the heterophase Sb ₂ Se ₃ is further enhanced, indicating that the content of the heterophase Sb ₂ Se ₃ in the sample of Example 3 is increased. It has been detected that in the sample films obtained by changing the annealing temperature in Examples 4 and 5, the atomic ratios of antimony and copper deviate from the 1:1 atomic ratio of Sb:Cu of CuSbSe ₂ . Wherein: the sample Sb:Cu atomic ratio of Example 4 is lower than 1:1, rich in copper; while the sample Sb:Cu atomic ratio of Example 5 is higher than 1:1, rich in antimony.

Summary: The light absorbing layer of copper antimony selenium (CuSbSe ₂ ) thin film solar cells is sensitive to the prefabricated layer composition and annealing temperature. Examples 1, 2, and 3 show that the thickness ratio of Sb ₂ Se ₃ and Cu ₂ Se in the prefabricated layer has a great influence on the phase of the final film, and the thickness ratio of Sb ₂ Se ₃ and Cu ₂ Se in the prefabricated layer is biased. A higher value will lead to the existence of Sb ₂ Se ₃ impurity phase in the annealed film. Examples 4 and 5 show that if the annealing temperature is too high, the film will be rich in copper, and if the annealing temperature is too low, the film will be rich in antimony. Therefore, the proportion of Sb ₂ Se ₃ and Cu ₂ Se in the preformed film and the annealing temperature must be precisely controlled.

Claims (2)

1. A preparation method of a photovoltaic absorption layer film of a copper antimony selenium solar cell is characterized by comprising the following steps:

preparing the copper antimony selenium film by adopting a method of sequentially sputtering and depositing a selenide prefabricated layer and then annealing, wherein the selenide prefabricated layer is of a double-layer structure of cuprous selenide and antimony selenide; by regulating Sb ₂ Se ₃ And Cu ₂ The sputtering time and the sputtering power of Se are controlled in the Sb to Cu atomic ratio range of 1.65-1.75; the method comprises the following steps:

step 1: preparation of selenide preform layer

Fixing an FTO substrate on a substrate tray of a vacuum chamber of a magnetron sputtering system, vacuumizing to a target vacuum, and sequentially depositing Sb by using radio frequency magnetron sputtering ₂ Se ₃ Layer and Cu ₂ The Se layer controls the ratio of Sb and Cu elements in the prefabricated layer by controlling the sputtering power and the deposition time of the two layers to obtain an antimony-rich prefabricated layer;

step 2: annealing of selenized prefabricated film layer

Placing the selenide prefabricated layer obtained in the step 1 in a vacuum tube furnace, firstly vacuumizing, then heating the substrate to a target temperature for annealing, so that Sb in the selenide prefabricated layer ₂ Se ₃ And Cu ₂ Se fully reacts and crystallizes to finally obtain the CuSbSe ₂ A film;

in step 1, sb ₂ Se ₃ The sputtering power of the layer is 20-100W, and the sputtering time is 21 minutes; cu (copper) ₂ The sputtering power of the Se layer is 20-80W, and the sputtering time is 9 minutes; the distance between the target material and the substrate is 3-5cm;

in step 2, annealing is carried out in a vacuum tube furnace, and the substrate is annealedRaising the temperature from room temperature to 380 ℃ within 20 minutes, preserving the heat for 10 minutes, and naturally cooling after annealing to obtain the CuSbSe ₂ A film.

2. The method of claim 1, wherein:

in step 1, an FTO substrate is placed on a substrate tray of a vacuum chamber of a magnetron sputtering coating system, and the pressure of the vacuum chamber is pumped to 5 multiplied by 10 ^-4 Pa, introducing argon, adjusting the air pressure of the vacuum chamber to 1.6Pa, and sequentially depositing Sb by adopting radio frequency magnetron sputtering ₂ Se ₃ Layer and Cu ₂ And a Se layer.

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