Solid state selenium diffusion process and its application in antimony-based solar cells

Abstract

The application discloses a solid selenium diffusion process and application thereof in antimony-based solar cells. Advantages of the solid selenium diffusion process are as follows: 1) the evaporation temperature and annealing crystallization temperature of selenium are very low (about 200 DEG C), so that the temperature of the solid selenium diffusion process is much lower than that (about 350 DEG C) of a conventional selenization process based on selenium vapor; 2) a high-quality antimony selenide interface layer can be prepared by using the process, the interface band structure between an absorption layer and a back electrode can be optimized, and the carrier transport of the device can be improved; 3) the solid selenium diffusion process is highly compatible with a full-vacuum process of the antimony-based solar cell, and can realize full-process physical preparation, and is suitable for large-area industrial manufacturing; and 4) the full-inorganic photovoltaic device prepared by using the solid selenium diffusion process has the advantages of low material cost, environmental friendliness, high stability and the like, and the indoor photovoltaic efficiency of the prepared device is as high as 12.00%, and the device has a wide application prospect in the field of indoor photovoltaic.

Description

Technical Field

[0001] This invention relates to a solid-state selenium diffusion process and its application in antimony-based solar cells, belonging to the field of solar energy technology. Background Technology

[0002] Indoor photovoltaic (PV) technology, as an advanced energy supply solution for sustainable IoT systems, can convert indoor ambient light energy into electrical energy, providing sustainable power supply for low-power IoT electronic devices and solving the problems of short battery life and high maintenance costs of traditional batteries. However, indoor light intensity is low and spectral distribution is complex. Traditional PV cell systems, such as monocrystalline silicon cells, have low efficiency under indoor lighting conditions, making it difficult to fully meet the actual energy supply needs of IoT nodes. In recent years, antimony-based PV cells with Sb2S3 as the core light absorption layer have become a promising candidate system for indoor PV due to their excellent material and photoelectric properties. These materials have advantages such as high absorption coefficient, abundant reserves, low cost, and outstanding environmental friendliness (Adv. Funct. Mater. 2021, 31(27):2100265). At the same time, the preparation process of antimony-based cells is simple, and high-quality thin films can be prepared through low-cost processes such as near-space sublimation and solution methods, showing good preparation compatibility and potential for large-scale application.

[0003] In the development of high-efficiency antimony-based photovoltaic devices, the interfacial contact between the light-absorbing layer and the back electrode is a key bottleneck restricting device performance. Due to poor bandgap matching between the absorber layer and the back electrode, as well as the deep valence band position, numerous surface defects, and easy pinning of the Fermi level, it is difficult to form an ideal ohmic contact with commonly used metal electrodes, resulting in a high hole extraction barrier and interfacial contact resistance (Nano Select 2021, 2: 1818-1848). Simultaneously, some metal electrodes are prone to interfacial reactions with the absorber layer during deposition or heat treatment, generating impurity phases and further increasing series resistance. These interfacial contact problems directly lead to reduced carrier extraction efficiency and severe interfacial recombination, resulting in a significant decrease in the cell's short-circuit current, fill factor, and open-circuit voltage, ultimately limiting the improvement of photoelectric conversion efficiency and affecting the stability and repeatability of the device.

[0004] Antimony-based photovoltaic cells, with their excellent material properties and fabrication advantages, have shown broad application potential in the field of indoor photovoltaic power supply. However, the interfacial contact problem between the light-absorbing layer and the metal back electrode has become a core technical bottleneck restricting the performance improvement of antimony-based photovoltaic devices and hindering their industrial application. Therefore, it is urgent to find efficient interface control strategies to optimize interfacial contact characteristics and promote the practical application of antimony-based photovoltaic technology in the field of Internet of Things (IoT) power supply. Summary of the Invention

[0005] This invention addresses the pain points in the aforementioned solar cell fabrication technologies by providing a solid-state selenium diffusion process. This process utilizes thermal evaporation and rapid annealing to prepare an antimony selenide interface layer, effectively improving the contact between the antimony-based absorber layer film and the back electrode. This method offers advantages such as low material cost, environmental friendliness, simple process, and high compatibility.

[0006] This invention relates to a solid-state selenium diffusion process, which first involves rapidly depositing an amorphous selenium film on the surface of an antimony sulfide film via thermal evaporation, followed by rapid thermal annealing in air to selenize the antimony sulfide surface and form antimony selenide. The process includes the following steps:

[0007] Antimony sulfide thin film substrate was fixed in the substrate of the thermal evaporation device. Selenium particles were placed inside the thermal evaporation device. The vacuum pump was turned on and the sealed chamber was opened. When the vacuum degree was less than 1 Pa, the molecular pump was turned on. When the vacuum degree was less than 5 × 10⁻⁶ Pa, the process was continued. -4 At Pa, turn on the heating power supply and rotate the substrate. After the evaporation rate is stabilized, open the baffle at the substrate to start evaporating the amorphous selenium film. When the film thickness reaches 100 nm, turn off the baffle, heating power supply, substrate rotation, molecular pump and vacuum pump, and open the venting valve. When the chamber pressure is the same as the atmospheric pressure, take out the substrate. Place the taken-out substrate on a hot stage at 200-220℃ for air atmosphere annealing for 2-4 minutes. After natural cooling, take out the sample.

[0008] Furthermore, the evaporation rate was controlled to be stable at 1 nm / s during the preparation of amorphous selenium thin films.

[0009] Furthermore, the preferred annealing temperature on the hot plate is 215°C, and the preferred annealing time is 2 minutes.

[0010] This invention also provides an antimony-based solar cell, the device structure of which, from bottom to top, is configured as a conductive substrate / zinc oxide electron transport layer / antimony sulfide absorber layer / antimony selenide interface layer / back electrode. The antimony selenide interface layer is prepared using the aforementioned solid-state selenium diffusion process.

[0011] The construction of the antimony-based solar cell of the present invention includes the following steps:

[0012] Step 1: Fabrication of zinc oxide electron transport layer by magnetron sputtering

[0013] First, open the vacuum coating machine chamber and fix the conductive substrate on the platform. Then, install the ZnO target and adjust its height so that the distance between the target and the substrate is 10 cm. Turn on the power to the magnetron sputtering equipment, and then turn on the mechanical pump switch and the fore-stage valve switch in sequence to start evacuation. When the vacuum level reaches 1-10 Pa, open the shut-off valve, then open the gas cylinder and gas flow meter, and introduce argon gas at a small flow rate (5 sccm) to clear the pipeline (10-15 seconds). When the vacuum level reaches 5 Pa, turn on the molecular pump until it reaches 1 × 10⁻⁶ Pa. -3High vacuum (Pa). Introduce a certain ratio of oxygen and argon to adjust the gas pressure to 0.1-5 Pa. Turn on the RF power supply, adjust the voltage and current buttons to change the sputtering power, and sputter for 2-5 minutes, with oxygen introduction time of 1-3 minutes. After sputtering is complete, turn off the molecular pump and mechanical pump in sequence. After the equipment has completely stopped, open the vent valve and remove the substrate.

[0014] Step 2: Sintering of antimony sulfide source plate powder blank

[0015] Raise the furnace cover using the lifting rod, remove the graphite plate from the near-space sublimation device, spread antimony sulfide powder evenly on it, and compact it with a quartz plate to obtain an antimony sulfide powder blank. Then place it back into the quartz furnace cavity; lower the lifting rod, turn on the vacuum pump to seal the cavity, and when the vacuum degree is less than 1 Pa, turn on the water cooler; set and start the sintering program: heat the lower graphite plate with an infrared heat source for 3-5 minutes to raise the temperature to 540-550℃ and hold it for 10-20 minutes to fuse the loose antimony sulfide powder blank into a dense structure; after the program is completed, wait for the water cooler to cool the cavity to room temperature.

[0016] Step 3: Preparation of antimony sulfide thin films by near-space sublimation method

[0017] Turn on the equipment power, place the conductive substrate with the conductive surface facing down in the graphite plate on the quartz furnace, and then fix the upper graphite plate in the upper infrared heat source area. After fixing, use the lifting rod to close the furnace chamber, then close the inlet valve, open the outlet valve, and simultaneously turn on the vacuum pump to evacuate the quartz furnace chamber. When the vacuum degree is less than 1 Pa, turn on the water chiller, set the evaporation program required for deposition, and start the thin film deposition at a certain substrate temperature and source temperature. After the program is completed, use the water chiller to cool the equipment to room temperature, turn off the water chiller and vacuum pump, open the inlet valve, and when the furnace pressure is the same as the atmospheric pressure, remove the thin film.

[0018] Step 4: Preparation of antimony selenide interface layer by thermal evaporation method

[0019] The sample prepared in step 3 was fixed in the substrate of the thermal evaporation apparatus, and the selenium particles were fixed in the crucible inside the thermal evaporation apparatus. The vacuum pump sealing chamber was opened, and when the vacuum degree was less than 1 Pa, the molecular pump was opened until the vacuum degree was less than 5 × 10⁻⁶ Pa. -4 At a pressure of Pa, turn on the heating power and rotate the substrate. After the evaporation rate stabilizes, open the baffle at the substrate to begin evaporating the amorphous selenium film. When the film thickness reaches 100 nm, turn off the baffle, heating power, substrate rotation, molecular pump, and vacuum pump. Open the venting valve. When the chamber pressure is the same as atmospheric pressure, remove the substrate. Place the removed substrate on a hot stage at 200-220℃ for air annealing for 2-4 minutes. After natural cooling, remove the sample.

[0020] Step 5: Preparation of metal electrodes

[0021] The sample obtained in step 4 was placed in a thermal evaporation apparatus to deposit metal electrodes. The evaporation current was 120-130A, the evaporation voltage was 3-4V, and the evaporation time was 5-10 minutes. This completed the fabrication of the antimony sulfide thin-film solar cell.

[0022] In step 1, the conductive substrate needs to be pretreated before use. Specifically, the conductive substrate is cut to the required size and ultrasonically cleaned with deionized water, acetone and ethanol for 15-20 minutes in sequence. After cleaning, it is dried with a nitrogen air gun and then treated with an ultraviolet ozone cleaner for 20-30 minutes.

[0023] In step 1, the conductive substrate is selected from FTO or ITO conductive substrates.

[0024] In step 1, the preferred oxygen-argon volume ratio is 1:2.

[0025] In step 1, the sputtering power during the deposition process is preferably 70W.

[0026] In step 1, the sputtering time is preferably 3 minutes.

[0027] In step 1, the oxygenation time is preferably 1 minute.

[0028] In step 3, during the deposition process, the substrate isothermal temperature is preferably 300-320℃, the evaporation source deposition temperature is preferably 520-540℃, and the deposition time is preferably 1-2 minutes.

[0029] In step 3, 5-10g of powder is placed in the antimony sulfide source plate, and the powder is evenly spread in the central area of ​​the graphite plate using a quartz plate compaction standard.

[0030] In step 4, 0.1g of selenium particles are placed in the crucible when preparing the amorphous selenium thin film.

[0031] In step 4, the evaporation rate is controlled to be stable at 1 nm / s when preparing the amorphous selenium thin film.

[0032] In step 4, the thickness of the amorphous selenium thin film is monitored using a film thickness gauge during the preparation of the film.

[0033] In step 4, the preferred annealing temperature on the hot plate is 215℃, and the preferred annealing time is 2 minutes.

[0034] In step 5, the metal electrode is a gold, silver, or copper electrode.

[0035] In this invention, the water cooler is always on during the vacuum processing and thin film sputtering processes. The vacuum pump is always on during the vacuum processing and thin film deposition processes.

[0036] Compared with existing technologies, the innovations and advantages of this invention are mainly reflected in the following aspects:

[0037] (1) Lowering the selenization process temperature: The evaporation temperature and annealing crystallization temperature of selenium are very low (~200℃), making the solid selenium diffusion process temperature much lower than the traditional selenization process based on selenium vapor (~350℃).

[0038] (2) Improve device back contact: This process can be used to prepare a high-quality antimony selenide interface layer, which can optimize the interface band structure between the absorption layer and the back electrode and improve the carrier transport of the device.

[0039] (3) Process compatibility: The solid-state selenium diffusion process is highly compatible with the all-vacuum process of antimony-based solar cells, enabling the entire process to be prepared by physical methods, and is suitable for large-area industrial manufacturing.

[0040] (4) Device advantages: The all-inorganic photovoltaic device prepared by solid-state selenium diffusion process has the advantages of low material cost, environmental friendliness and high stability. At the same time, the indoor photovoltaic efficiency of the prepared device is as high as 12.00%, showing broad application prospects in the field of indoor photovoltaic. Attached Figure Description

[0041] Figure 1 This is a scanning electron microscope (SEM) image of the antimony selenide interface layer prepared by solid-state selenium diffusion process. The film surface is smooth and dense.

[0042] Figure 2 This is the X-ray diffraction (XRD) spectrum of an antimony sulfide thin film with an antimony selenide interface layer prepared by a solid-state selenium diffusion process. As can be seen from the figure, compared to the strong diffraction peaks of the conductive substrate and the antimony sulfide thin film, the antimony selenide interface layer exhibits a weaker diffraction signal.

[0043] Figure 3 This is a schematic diagram of the antimony sulfide thin-film solar cell structure of the present invention. From bottom to top, it consists of a conductive substrate, a zinc oxide electron transport layer, an antimony sulfide absorber layer, an antimony selenide interface layer, and a metal electrode.

[0044] Figure 4 The image shows the photocurrent density-voltage (JV) curve of an antimony sulfide solar cell with an antimony selenide interface layer prepared by solid-state selenium diffusion process under 1000 lux irradiation. The indoor photovoltaic efficiency of the device can reach 12.00%.

[0045] Figure 5 This is a flowchart of the fabrication process for antimony-based solar cells. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1: Optimization of oxygen permeation time in zinc oxide electron transport layer

[0048] 1. Cleaning of conductive substrate

[0049] Cut the FTO substrate to the required size and ultrasonically clean it sequentially with deionized water, acetone, and ethanol for 15 minutes. After cleaning, dry the glass with a nitrogen gas gun and then treat it with a UV ozone cleaner for 20 minutes before taking it out for use.

[0050] 2. Preparation of zinc oxide electron transport layer

[0051] A zinc oxide electron transport layer was deposited using magnetron sputtering. The cleaned FTO substrate from step one was fixed on a rotating disk, and the ZnO target was fixed inside the magnetron sputtering deposition machine cavity. The target height was adjusted to a distance of 10 cm between the target and the substrate, and the cover was closed. The magnetron sputtering deposition machine cavity was then subjected to vacuum treatment at a vacuum level of 5 × 10⁻⁶. -3 At Pa, oxygen and argon are introduced in a 1:2 ratio to adjust the gas pressure to 1.3 Pa. The RF power supply is turned on, and the voltage and current buttons are adjusted to power 70W. Sputtering is performed for 3 minutes, with oxygen introduced for 1-3 minutes. After sputtering, the molecular pump and mechanical pump are turned off in sequence, the vent valve is opened, and the substrate is removed when the gas pressure in the sputtering chamber is the same as atmospheric pressure.

[0052] 3. Sintering of antimony sulfide source plate powder blank

[0053] Raise the furnace top cover using the lifting rod, remove the graphite plate from the near-space sublimation device, spread 15g of antimony sulfide powder on it, and compact it with a quartz plate to obtain an antimony sulfide powder blank. Then place it back into the quartz furnace cavity; lower the lifting rod, turn on the vacuum pump to seal the cavity, and turn on the water cooler when the vacuum degree is less than 1Pa; set and start the sintering program: heat the lower graphite plate with an infrared heat source for 3 minutes to raise the temperature to 550℃ and hold for 10 minutes to fuse the loose antimony sulfide powder blank into a dense structure; after the program is completed, wait for the water cooler to cool the cavity to room temperature.

[0054] 4. Preparation of antimony sulfide absorber layer

[0055] Antimony sulfide absorber layers were prepared using the aforementioned near-space sublimation apparatus. The thin film prepared in step 2 was placed in the upper graphite plate, and the lower graphite plate, from which the antimony sulfide powder preform was sintered in step 3, was placed back into the quartz furnace cavity. The distance between the upper and lower graphite plates was adjusted using a lifting rod. The inlet valve was closed, and a vacuum pump was used to evacuate the furnace for 15 minutes before film deposition began. The water chiller was turned on, and the required evaporation program for deposition was set to begin film deposition. The evaporation process was as follows: the upper and lower graphite layers were heated to 300°C within 2 minutes and held at that temperature for 15 minutes to ensure uniform heating of the source and substrate; then, the source temperature was raised to 540°C over 60 seconds, while the substrate temperature remained constant, and deposition lasted for 1.5 minutes before the program ended. After the program ended, the equipment was cooled to room temperature using the water chiller, the water chiller and vacuum pump were turned off, the inlet valve was opened, and the film was removed when the furnace pressure was equal to atmospheric pressure.

[0056] 5. Preparation of metal electrodes: The sample prepared in step 4 is placed in a thermal evaporation device to deposit metal electrodes, thus completing the preparation of antimony sulfide thin-film solar cells.

[0057]

[0058] As shown in Table 1, the oxygen permeation time during the fabrication of the zinc oxide electron transport layer has a significant impact on device performance. The device performance is best when the zinc oxide electron transport layer is permeated with oxygen for 1 minute.

[0059] Example 2: Comparison of device performance with and without solid-state selenide diffusion process for antimony selenide interface layer

[0060] 1. Cleaning of conductive substrate

[0061] Cut the FTO substrate to the required size and ultrasonically clean it sequentially with deionized water, acetone, and ethanol for 15 minutes. After cleaning, dry the glass with a nitrogen gas gun and then treat it with a UV ozone cleaner for 20 minutes before taking it out for use.

[0062] 2. Preparation of zinc oxide electron transport layer

[0063] Zinc oxide thin films were deposited using magnetron sputtering. The cleaned FTO substrate from step one was fixed on a rotating disk, and the ZnO target was fixed inside the magnetron sputtering deposition machine cavity. The target height was adjusted to a distance of 10 cm between the target and the substrate, and the cover was closed. The magnetron sputtering deposition machine cavity was then subjected to vacuum treatment at a vacuum level of 5 × 10⁻⁶. -3 At Pa, oxygen and argon were introduced in a 1:2 ratio to adjust the gas pressure to 1.3 Pa. The RF power supply was turned on, and the voltage and current buttons were adjusted to a power of 70W. Sputtering was performed for 3 minutes, with an oxygen purging time of 1 minute. After sputtering, the molecular pump and mechanical pump were turned off in sequence, the vent valve was opened, and the substrate was removed when the gas pressure in the sputtering chamber was the same as atmospheric pressure.

[0064] 3. Sintering of antimony sulfide source plate powder blank

[0065] Raise the furnace top cover using the lifting rod, remove the graphite plate from the near-space sublimation device, spread 10g of antimony sulfide powder on it, and compact it with a quartz plate to obtain an antimony sulfide powder blank. Then place it back into the quartz furnace cavity; lower the lifting rod, turn on the vacuum pump to seal the cavity, and turn on the water cooler when the vacuum degree is less than 1Pa; set and start the sintering program: heat the lower graphite plate with an infrared heat source for 3 minutes to raise the temperature to 550℃ and hold for 10 minutes to fuse the loose antimony sulfide powder blank into a dense structure; after the program ends, wait for the water cooler to cool the cavity to room temperature.

[0066] 4. Preparation of antimony sulfide absorber layer

[0067] Antimony sulfide absorber layers were prepared using the aforementioned near-space sublimation apparatus. The thin film prepared in step 2 was placed in the upper graphite plate, and the lower graphite plate, from which the antimony sulfide powder preform was sintered in step 3, was placed back into the quartz furnace cavity. The distance between the upper and lower graphite plates was adjusted using a lifting rod. The inlet valve was closed, and a vacuum pump was used to evacuate the furnace for 15 minutes before film deposition began. The water chiller was turned on, and the required evaporation program for deposition was set to begin film deposition. The evaporation process was as follows: the upper and lower graphite layers were heated to 300°C within 2 minutes and held at that temperature for 15 minutes to ensure uniform heating of the source and substrate; then, the source temperature was raised to 540°C over 60 seconds, while the substrate temperature remained constant, and deposition lasted for 1.5 minutes before the program ended. After the program ended, the equipment was cooled to room temperature using the water chiller, the water chiller and vacuum pump were turned off, the inlet valve was opened, and the substrate was removed when the furnace pressure was equal to atmospheric pressure.

[0068] 5. Preparation of the antimony selenide interface layer: The sample obtained in step 4 is fixed in the substrate of the thermal evaporation apparatus. 0.1g of selenium particles are added to the crucible and fixed inside the thermal evaporation apparatus. The vacuum pump sealing chamber is opened. When the vacuum degree is less than 1 Pa, the molecular pump is turned on. The process continues until the vacuum degree is less than 5 × 10⁻⁶ Pa. -4 At pressure Pa, the heating power supply and substrate rotation were turned on. Once the evaporation rate was stabilized at 1 nm / s, the baffle at the substrate was opened to begin evaporating the amorphous selenium film. The film thickness was measured using a film thickness gauge. When the thickness reached 100 nm, the baffle, heating power supply, substrate rotation, molecular pump, and vacuum pump were turned off. The venting valve was opened, and the substrate was removed when the chamber pressure equalized with atmospheric pressure. The removed substrate was then placed on a hot stage at 215°C for air annealing for 2 minutes. After natural cooling, the sample was removed.

[0069] 6. Preparation of metal electrodes: Place the sample obtained in step 5 into a thermal evaporation device to deposit metal electrodes, thus completing the preparation of antimony sulfide thin-film solar cells.

[0070]

[0071] As can be seen from Table 2, the device performance is significantly improved after adding the antimony selenide interface layer prepared by the solid-state selenium diffusion process.

Claims

1. A solid-state selenium diffusion process, characterized in that: First, an amorphous selenium film is rapidly deposited on the surface of an antimony sulfide film using a thermal evaporation process. Then, rapid thermal annealing in air is performed to selenize the surface of the antimony sulfide film, forming antimony selenide. This process includes the following steps: Antimony sulfide thin film substrate was fixed in the substrate of the thermal evaporation device. Selenium particles were placed inside the thermal evaporation device. The vacuum pump was turned on and the sealed chamber was opened. When the vacuum degree was less than 1 Pa, the molecular pump was turned on. When the vacuum degree was less than 5 × 10⁻⁶ Pa, the process was continued. -4 At Pa, turn on the heating power supply and rotate the substrate. After the evaporation rate is stabilized, open the baffle at the substrate to start evaporating the amorphous selenium film. When the film thickness reaches 100 nm, turn off the baffle, heating power supply, substrate rotation, molecular pump and vacuum pump, and open the venting valve. When the chamber pressure is the same as the atmospheric pressure, take out the substrate. Place the taken-out substrate on a hot stage at 200-220℃ for air atmosphere annealing for 2-4 minutes. After natural cooling, take out the sample.

2. The solid-state selenium diffusion process according to claim 1, characterized in that: The evaporation rate was kept constant at 1 nm / s during the preparation of amorphous selenium thin films.

3. The solid-state selenium diffusion process according to claim 1, characterized in that: The annealing temperature on the hot plate is 215℃, and the annealing time is 2 minutes.

4. An antimony-based solar cell, characterized in that: The device structure of the antimony-based solar cell, from bottom to top, is configured as a conductive substrate / zinc oxide electron transport layer / antimony sulfide absorber layer / antimony selenide interface layer / back electrode. The antimony selenide interface layer is prepared based on the solid-state selenium diffusion process described in claim 1, 2 or 3.

5. The antimony-based solar cell according to claim 4, characterized in that... Its construction method includes the following steps: Step 1: Fabrication of zinc oxide electron transport layer by magnetron sputtering The conductive substrate was fixed on the stage, and then the ZnO target was installed and its height adjusted so that the distance between the target and the substrate was 10 cm. When the vacuum level reached 1-10 Pa, the shut-off valve was opened, and then argon gas was introduced to clear the pipeline. When the vacuum level reached 5 Pa, the molecular pump was turned on until it reached 1 × 10 Pa. -3 High vacuum of Pa, introduce a certain proportion of oxygen and argon to adjust the gas pressure to 0.1-5 Pa, turn on the RF power supply, adjust the voltage and current buttons to change the sputtering power, sputter for 2-5 minutes, oxygen introduction time 1-3 minutes, after sputtering is completed, turn off the molecular pump and mechanical pump in sequence, and after the equipment is completely shut down, open the vent valve and take out the substrate. Step 2: Sintering of antimony sulfide source plate powder blank Remove the graphite plate from the near-space sublimation equipment, spread antimony sulfide powder on it, and compact it with a quartz plate to obtain an antimony sulfide powder blank. Then place it back into the quartz furnace cavity. When the vacuum degree is less than 1 Pa, turn on the water cooler, set and start the sintering program: heat the graphite plate with an infrared heat source for 3-5 minutes to raise the temperature to 540-550℃ and hold it for 10-20 minutes to make the loose antimony sulfide powder blank melt into a dense structure. Step 3: Preparation of antimony sulfide thin films by near-space sublimation method Place the conductive substrate with the conductive surface facing down in the graphite plate on the quartz furnace, and then fix the graphite plate to the upper infrared heat source area; when the vacuum degree is less than 1 Pa, turn on the water chiller, set the evaporation program required for deposition, and start the deposition of the thin film at a certain substrate temperature and source temperature; after the program is completed, use the water chiller to cool the equipment to room temperature, and when the furnace gas pressure is the same as the atmospheric pressure, take out the thin film. Step 4: Preparation of antimony selenide interface layer by thermal evaporation method The sample prepared in step 3 was fixed in the substrate of the thermal evaporation device. The selenium particles were fixed inside the thermal evaporation device. When the vacuum degree was less than 1 Pa, the molecular pump was turned on. When the vacuum degree was less than 5 × 10⁻⁶ Pa, the process was continued. -4 At Pa, turn on the heating power supply and rotate the substrate. After the evaporation rate is stabilized, open the baffle at the substrate to start evaporating the amorphous selenium film. When the film thickness reaches 100nm, turn off the baffle, heating power supply, substrate rotation, molecular pump and vacuum pump, and open the venting valve. When the chamber pressure is the same as the atmospheric pressure, take out the substrate. Place the taken-out substrate on a hot stage at 200-220℃ for air atmosphere annealing for 2-4 minutes. After natural cooling, take out the sample. Step 5: Preparation of the back electrode The sample obtained in step 4 is placed in a thermal evaporation device to deposit metal electrodes. The evaporation current is 120-130A, the evaporation voltage is 3-4V, and the evaporation time is 5-10 minutes, thus completing the preparation of antimony sulfide thin film solar cells.

6. The antimony-based solar cell according to claim 5, characterized in that: In step 1, the volume ratio of oxygen to argon is 1:

2.

7. The antimony-based solar cell according to claim 5, characterized in that: In step 1, the sputtering power during deposition is 70W, the sputtering time is 3 minutes, and the oxygenation time is 1 minute.

8. The antimony-based solar cell according to claim 5, characterized in that: In step 3, during deposition, the substrate is kept at a constant temperature of 300-320℃, the evaporation source deposition temperature is 520-540℃, and the deposition time is 1-2 minutes.

9. The antimony-based solar cell according to claim 5, characterized in that: In step 4, the evaporation rate is controlled to be stable at 1 nm / s when preparing the amorphous selenium thin film.

10. The antimony-based solar cell according to claim 5, characterized in that: In step 4, the annealing temperature on the hot plate is 215℃, and the annealing time is 2 minutes.

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