阅读说明：本技术 一种基于SnO2缓冲层Sb2Se3太阳能电池的制备方法 (Buffer layer Sb based on SnO22Se3Preparation method of solar cell ) 是由 谭婷婷 徐云海 孟庆岱 魏登科 查钢强 李颖锐 吴森 于 2021-06-17 设计创作，主要内容包括：本发明涉及一种基于SnO-(2)缓冲层Sb-(2)Se-(3)太阳能电池的制备方法,选用磁控溅射法沉积SnO-(2)薄膜,近空间升华法CSS沉积Sb-(2)Se-(3)薄膜,并对SnO-(2)薄膜和Sb-(2)Se-(3)薄膜分别进行退火改性,最后制备出了FTO/SnO-(2)/Sb-(2)Se-(3)/Au顶衬结构的薄膜太阳能电池器件。磁控溅射法与喷雾热解法、低温热解法相比,制备的SnO-(2)薄膜更加致密,纯度更高,重复性更好,厚度可控,在高真空腔室下溅射有效的避免了杂质的引入,制备的薄膜均匀性更好且不会产生废液和任何有害气体；CSS是一种将源材料加热使其快速升华并且在衬底上沉积薄膜的一种制备方法,CSS源的利用率高、工艺简单、重复性好、膜层纯度高,因此CSS制备的Sb-(2)Se-(3)薄膜更加适合商业化生产。(The invention relates to a method based on SnO 2 Buffer layer Sb 2 Se 3 The preparation method of the solar cell adopts a magnetron sputtering method to deposit SnO 2 Thin film, close space sublimation CSS deposition of Sb 2 Se 3 Thin film and for SnO 2 Film and Sb 2 Se 3 Respectively annealing and modifying the film to finally prepare the FTO/SnO 2 /Sb 2 Se 3 The thin-film solar cell device has an Au top lining structure. Compared with spray pyrolysis method and low-temperature pyrolysis method, the prepared SnO by the magnetron sputtering method 2 The film is more compact, the purity is higher, the repeatability is better, the thickness is controllable, the introduction of impurities is effectively avoided by sputtering under a high vacuum chamber, the uniformity of the prepared film is better, and waste liquid and any harmful gas cannot be generated; CSS is a preparation method for heating a source material to sublimate the source material rapidly and depositing a thin film on a substrate, and the CSS source has high utilization rate, simple process, good repeatability and high film purity, so Sb prepared by CSS 2 Se 3 The film is more suitable for commercial production.)

1. SnO (stannic oxide) -based₂Buffer layer Sb₂Se₃The preparation method of the solar cell is characterized by comprising the following steps:

step 1, preparing SnO by adopting magnetron sputtering method₂Film formation: target SnO₂The distance between the FTO conductive glass substrate and the FTO conductive glass substrate is 8-10 cm, the working pressure is 1-5 Pa, the deposition time is 3-5 min, the substrate temperature is 100-400 ℃, one group of sputtering atmosphere is pure argon, and the other group is Ar/O₂1:1, the flow is 25sccm, the sputtering power of a radio frequency power supply is 100W, and finally annealing is carried out for 20-40 min in an air atmosphere at 400-500 ℃ to obtain SnO on the substrate₂A film;

step 2, preparing Sb by using a near space sublimation method₂Se₃Film formation: deposition of SnO₂FTO glass substrate of buffer layer is arranged on an upper heating table, and a sublimation source Sb₂Se₃Pressing the powder into tablets, placing the tablets on a lower heating table, SnO₂Buffer layer and sublimation source Sb₂Se₃Oppositely placing the two materials, wherein the distance between the two materials is 4-5 mm, the temperature of an upper heating table is 250 ℃, the temperature of a lower heating table is 450-480 ℃, the deposition time is 3600-7200S, and finally, Sb is treated at 325-375 DEG C₂Se₃Respectively carrying out in-situ annealing and selenizing annealing on the film for 20-40 min, and carrying out annealing on the film in SnO₂Obtaining Sb on the film₂Se₃A film;

and step 3: by vacuum evaporation on Sb₂Se₃And Au electrodes are plated on the upper surface of the light absorption layer and the FTO conductive glass on one side of the light absorption layer to form the antimony selenide thin-film solar cell.

2. A SnO-based composition according to claim 1₂Buffer layer Sb₂Se₃The preparation method of the solar cell is characterized by comprising the following steps: the FTO conductive glass substrate is firstly cleaned, the FTO conductive glass is sequentially ultrasonically cleaned by acetone, absolute ethyl alcohol and deionized water, the ultrasonically cleaned FTO conductive glass is dried by high-pressure nitrogen, and the FTO conductive glass is placed in a glass container paved with dust-free cloth for storage.

3. A SnO-based composition according to claim 1₂Buffer layer Sb₂Se₃The preparation method of the solar cell is characterized by comprising the following steps: SnO prepared by magnetron sputtering method₂The film process parameters are as follows: deposition time 3min, substrate temperature 100 deg.C, sputtering atmosphere Ar/O₂1:1, in air atmosphere, annealing temperature 4Annealing at 50 deg.C for 30 min; the method for preparing Sb by using the near space sublimation method₂Se₃The process parameters of the film are as follows: the substrate temperature is 250 ℃, the growth source temperature is 470 ℃, the deposition time is 3600S, and the finally obtained solar cell has the parameter V after selenization annealing at 350 ℃ for 30min_OC＝274mV，J_SC＝28.25mA/cm²FF is 36.61%, PCE is 2.83%, and the device exhibits good stability and steady-state output characteristics.

Technical Field

The invention belongs to a preparation method of a solar cell, and relates to a preparation method based on SnO₂Buffer layer Sb₂Se₃A method for fabricating a solar cell.

Background

Nowadays, energy sources are increasingly in short supply, and development and utilization of new energy sources are concerned. Solar energy is a novel green nontoxic energy with abundant reserves, can effectively solve the energy crisis problem faced by human beings at present, and thin-film solar cells are always the research focus in the energy field due to the characteristics of lightness, less material consumption, flexibility and the like. Of these, copper indium gallium tin (CIGS) and cadmium telluride (CdTe) have been successfully commercialized, but since the elements In and Ga are expensive and Cd is biologically toxic, there is a continuing need to explore inexpensive and non-toxic light absorbing materials.

Studies have shown that antimony selenide (Sb)₂Se₃) The material has good photoelectric response, has larger absorption coefficient and better chemical stability in ultraviolet and visible light wave bands, and is very suitable to be used as a light absorption layer material of an inorganic thin-film solar cell. However, the main buffer layer material of the buffer layer is cadmium sulfide (CdS), on one hand, because of Cd⁺The diffusion at the heterojunction interface can cause the stability of the device to be poor, and on the other hand, the biological toxicity of Cd also limits Sb₂Se₃The development of thin film solar cells requires the search for new buffer layer materials. To date, Sb₂Se₃Solar cells have been provided with structures based on other different types of buffer layers, such as zinc oxide (ZnO), titanium dioxide (TiO)₂) And tin oxide (SnO)₂). The tin oxide is a semiconductor material which is non-toxic, low in cost and high in stability, has a larger band gap and high mobility, and is a promising CdS substitute.

At present, people generally adopt spray pyrolysis method and low-temperature solution method to prepare SnO₂Buffer layer prepared from Sb by rapid thermal evaporation₂Se₃An absorption layer. Wherein the spray pyrolysis method is used for preparing SnO₂Byproducts are easily generated in the process of the film, and the uniformity is poor during large-area preparation; the low temperature solution method generates waste liquid and harmful gas, and SnO₂The deposition rate is not easily controlled. Secondly, preparing Sb by adopting a rapid thermal evaporation method₂Se₃In the case of a thin film, although much faster than the conventional thermal evaporation method and sputtering method, further improvement of Sb is required to satisfy the requirement of commercial production while securing the quality of the thin film₂Se₃The deposition rate of the film.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides a SnO-based material₂Buffer layer Sb₂Se₃Of solar cellsThe preparation method is used for preparing the nontoxic efficient solar cell.

Technical scheme

SnO (stannic oxide) -based₂Buffer layer Sb₂Se₃The preparation method of the solar cell is characterized by comprising the following steps:

step 1, preparing SnO by adopting magnetron sputtering method₂Film formation: target SnO₂The distance between the FTO conductive glass substrate and the FTO conductive glass substrate is 8-10 cm, the working pressure is 1-5 Pa, the deposition time is 3-5 min, the substrate temperature is 100-400 ℃, one group of sputtering atmosphere is pure argon, and the other group is Ar/O₂1:1, the flow is 25sccm, the sputtering power of a radio frequency power supply is 100W, and finally annealing is carried out for 20-40 min in an air atmosphere at 400-500 ℃ to obtain SnO on the substrate₂A film;

step 2, preparing Sb by using a near space sublimation method₂Se₃Film formation: deposition of SnO₂FTO glass substrate of buffer layer is arranged on an upper heating table, and a sublimation source Sb₂Se₃Pressing the powder into tablets, placing the tablets on a lower heating table, SnO₂Buffer layer and sublimation source Sb₂Se₃Oppositely placing the two materials, wherein the distance between the two materials is 4-5 mm, the temperature of an upper heating table is 250 ℃, the temperature of a lower heating table is 450-480 ℃, the deposition time is 3600-7200S, and finally, Sb is treated at 325-375 DEG C₂Se₃Respectively carrying out in-situ annealing and selenizing annealing on the film for 20-40 min, and carrying out annealing on the film in SnO₂Obtaining Sb on the film₂Se₃A film;

and step 3: by vacuum evaporation on Sb₂Se₃And Au electrodes are plated on the upper surface of the light absorption layer and the FTO conductive glass on one side of the light absorption layer to form the antimony selenide thin-film solar cell.

The optimal process parameters are as follows: deposition time 3min, substrate temperature 100 deg.C, sputtering atmosphere Ar/O₂Annealing at 450 deg.C for 30min in air atmosphere at a ratio of 1: 1; sb preparation by near space sublimation method₂Se₃Film, under optimal process parameters: the substrate temperature is 250 ℃, the growth source temperature is 470 ℃, the deposition time is 3600S, and the finally obtained solar cell has the parameter V after selenization annealing at 350 ℃ for 30min_OC＝274mV，J_SC＝28.25mA/cm²FF is 36.61%, PCE is 2.83%, and the device exhibits good stability and steady-state output characteristics.

The FTO conductive glass substrate is firstly cleaned, the FTO conductive glass is sequentially ultrasonically cleaned by acetone, absolute ethyl alcohol and deionized water, the ultrasonically cleaned FTO conductive glass is dried by high-pressure nitrogen, and the FTO conductive glass is placed in a glass container paved with dust-free cloth for storage.

Advantageous effects

The invention provides a SnO (stannic oxide) -based material₂Buffer layer Sb₂Se₃The preparation method of the solar cell adopts a magnetron sputtering method to deposit SnO₂Thin film, Close Space Sublimation (CSS) deposition of Sb₂Se₃Thin film and for SnO₂Film and Sb₂Se₃Respectively annealing and modifying the film to finally prepare the FTO/SnO₂/Sb₂Se₃The thin-film solar cell device has an Au top lining structure, and the device shows good stability and steady-state output characteristics. Compared with spray pyrolysis method and low-temperature pyrolysis method, the prepared SnO by the magnetron sputtering method₂The film is more compact, the purity is higher, the repeatability is better, the thickness is controllable, the introduction of impurities is effectively avoided by sputtering under a high vacuum chamber, the uniformity of the prepared film is better, and waste liquid and any harmful gas cannot be generated; CSS is a fabrication method in which a source material is heated to be rapidly sublimated and a thin film is deposited on a substrate. The specific structure is shown as figure 1, in a sealed instrument, a source and a substrate are respectively placed on an AlN ceramic plate at the lower layer and a graphite mask at the upper layer, an upper group of infrared lamps and a lower group of infrared lamps respectively heat the substrate and a sublimation source to enable the temperature of the source to be higher than that of the substrate, and a balanced vapor pressure difference exists between the source and the substrate to enable gas phase atoms to be transported from the source to the substrate and deposited on the substrate. Compared with a rapid thermal evaporation method, the deposition rate of the CSS is higher (the deposition rate of the CSS is 10um/min, the rapid thermal evaporation method is 1um/min), and in addition, the utilization rate of a CSS source is high, the process is simple, the repeatability is good, and the purity of a film layer is high, so that Sb prepared by the CSS₂Se₃The film is more suitable for commercial production.

The invention adopts a magnetron sputtering methodPreparation of n-type buffer layer SnO₂A film is prepared by adopting a near space sublimation method to prepare a p-type light absorption layer Sb₂Se₃Film, successfully preparing FTO/SnO₂/Sb₂Se₃A solar cell device of Au structure. At SnO₂In the preparation process, the sputtering time is controlled to be 3min, so that SnO is reduced₂The roughness of the film improves the transmittance of the film in a visible wave band to 80-85%; by Ar/O₂1:1 sputtering atmosphere, reduction of SnO₂The oxygen vacancy defect of the film reduces the probability that the current carrier is captured by the oxygen vacancy chamber in the transmission process, the recombination loss and the SnO₂The transmittance of the film in a visible waveband is improved by 10-12%, and the efficiency of the film solar cell is improved; for SnO in air₂The film is annealed and modified, the density of the film is improved, the preferential growth surface is changed from (211) to (101), and the preferential growth along the C axis is favorable for the transmission of carriers. In Sb₂Se₃In the process of preparing the film, the source temperature is controlled at 470 ℃ to ensure that Sb is Sb₂Se₃Increase in the crystalline quality of the film, Sb₂Se₃The film is dense and the crystal grains are larger as shown in figure 15, and when the source temperature is 470 ℃, Sb is₂Se₃The (hk1) face abundance of the film was increased as shown in FIG. 12; sb after 350 ℃ in-situ annealing₂Se₃The peak position of the whole film is kept unchanged, the intensity of each peak is enhanced, the strongest peak of the film is still the (221) peak, the crystallization quality of the film is enhanced, and Sb is obtained after selenization annealing at 350 DEG C₂Se₃The strongest peaks of the film are (221) and (211), so that not only is the crystallization quality enhanced, but also the abundance of the (hk1) crystal plane is remarkably increased, and simultaneously, the abundance of the (hk0) crystal plane is reduced, and the peaks comprising (120), (230) and (240) are remarkably weakened, as shown in figure 17. As can be seen from FIG. 18, when the solar cell generates photo-generated carriers, the crystal grains grow along the (120) direction, and the carriers are (Se) on one hand during the transportation process₄Sb₆) The covalent bond transmission between the nano-bands needs to overcome the van der waals force to jump between the bands, and the energy required for the part of the jump is higher, which is not beneficial to the transmission of the carriers, and the (Se) which is grown along the (211) and (221) orientation is opposite₄Sb₆) Nano beltThe oblique direction is vertical to the substrate, more photogenerated carriers can be transmitted in the band, so that the jump between the bands is reduced, the transmission efficiency of the carriers is improved, the recombination loss is reduced, and the Sb can be increased through selenizing annealing at 350 DEG C₂Se₃The (hk1) crystal face abundance of the film further improves the battery performance; meanwhile, selenium vacancy formed in the evaporation process is filled by selenization annealing, and the film is more compact.

SnO prepared by magnetron sputtering method₂The film process parameters are as follows: deposition time 3min, substrate temperature 100 deg.C, sputtering atmosphere Ar/O₂Annealing at 450 deg.C for 30min in air atmosphere at a ratio of 1: 1; the method for preparing Sb by using the near space sublimation method₂Se₃The process parameters of the film are as follows: the substrate temperature is 250 ℃, the growth source temperature is 470 ℃, the deposition time is 3600S, and the finally obtained solar cell has the parameter V after selenization annealing at 350 ℃ for 30min_OC＝274mV，J_SC＝28.25mA/cm²FF is 36.61%, PCE is 2.83%, and the device exhibits good stability and steady-state output characteristics.

The optimal process parameters are as follows: deposition time 3min, substrate temperature 100 deg.C, sputtering atmosphere Ar/O₂Annealing at 450 deg.C for 30min in air atmosphere at a ratio of 1: 1; sb preparation by near space sublimation method₂Se₃Film, under optimal process parameters: the substrate temperature is 250 ℃, the growth source temperature is 470 ℃, the deposition time is 3600S, and the finally obtained solar cell has the parameter V after selenization annealing at 350 ℃ for 30min_OC＝274mV，J_SC＝28.25mA/cm²FF is 36.61%, PCE is 2.83%, and the device exhibits good stability and steady-state output characteristics.

Drawings

FIG. 1 is a schematic structural diagram of a close-space sublimation apparatus according to the present invention.

FIG. 2 shows a SnO-based catalyst of the present invention₂Buffer layer Sb₂Se₃The structure of the solar cell is schematically shown.

FIG. 3 shows a SnO-based catalyst of the present invention₂Buffer layer Sb₂Se₃In the preparation method of solar cellPreparing a flow chart and a material object chart.

FIG. 4 shows SnO at different deposition times in the present invention₂Transmission spectrum of the film.

FIG. 5 is SnO at different substrate temperatures in the present invention₂Transmission spectrum of the film.

FIG. 6 is SnO in the present invention₂Cell parameters at different deposition temperatures.

FIG. 7 is a schematic representation of SnO deposited in different atmospheres in accordance with the present invention₂PL Spectrum of thin film

FIG. 8 is SnO in the present invention₂J-V curves of the cells under different deposition atmospheres.

FIG. 9 shows SnO in different annealing treatment modes according to the present invention₂SEM image of the film;

(a) -not annealed; (b) annealing at 400 ℃; (c) annealing at 450 ℃; (d) annealing at-500 deg.C

FIG. 10 shows SnO in different annealing treatment modes according to the present invention₂XRD pattern of the film.

FIG. 11 is SnO in the present invention₂J-V curves of the cells at different annealing temperatures.

FIG. 12 shows Sb at different deposition temperatures according to the present invention₂Se₃XRD spectra of the films.

FIG. 13 shows Sb prepared at different temperatures according to the present invention₂Se₃Optical transmittance of the film.

FIG. 14 shows Sb in the present invention₂Se₃J-V curves of the cells at different preparation temperatures.

FIG. 15 shows Sb in different annealing modes according to the present invention₂Se₃SEM image of the surface appearance of the film;

(a) -annealing in situ; (b) -selenization annealing; (c) non-annealed

FIG. 16 shows Sb in different annealing modes according to the present invention₂Se₃J-V curves of thin film solar cells;

(a) -annealing in situ; (b) -selenization annealing; (c) non-annealed

FIG. 17 shows Sb in different annealing modes according to the present invention₂Se₃XRD spectrum of the film;

(a) -not annealed; (b) -annealing in situ; (c) annealing by selenization

FIG. 18 shows Sb in the present invention₂Se₃Film carrier at [120 ]]、[211]Or [221 ]]Directional transmission diagram

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

(1) substrate selection and cleaning:

the specification of Shenzhen Hunan Xiangcheng science and technology Limited company adopted by the invention is 15 multiplied by 15mm²FTO conductive glass with the thickness of 185 nm. Placing the FTO conductive glass in a 200ml beaker, ultrasonically cleaning the FTO conductive glass for 20-30 min by using acetone, absolute ethyl alcohol and deionized water in sequence, blow-drying the ultrasonically cleaned FTO conductive glass by using high-pressure nitrogen, and placing the glass into a glass container paved with dust-free cloth, wherein the cleaned FTO is used as soon as possible, and secondary pollution caused by long-time storage is avoided.

(2)SnO₂Preparing a buffer layer:

the invention adopts an MSP-300BT type magnetron sputtering coating machine of Wei Nake technology ltd, Chuangshi, Beijing, fixes the cleaned FTO glass substrate on a sample table, puts the FTO glass substrate into a vacuum chamber, and leads the magnetron sputtering target SnO₂The glass substrate is opposite to the upper surface of the glass substrate, and the distance is 8-10 cm; vacuumizing to make the vacuum degree of the chamber reach 2 x 10^-4Heating the sample table to 100-400 ℃ after Pa; when the sample platform is heated to the required temperature, the vacuum gauge is closed, the argon bottle air valve and the oxygen bottle air valve are sequentially opened to start air supply, then the air pressure in the chamber is regulated by controlling the gate valve to keep the air pressure at about 3Pa, the power source is started to prepare for glow starting, after the glow starting is successful, the radio frequency power is regulated to a set value, the reflection power is regulated to the lowest value, the gate valve is regulated to enable the air pressure in the chamber to reach 1-5 Pa, pre-sputtering is started, the sputtering time is 10-20min, and the purpose of the process is to remove impurities on the surface of the target material; after the pre-sputtering is finished, opening the shielding disc and the baffle plate, and starting timing sputtering; sputtering power of 100W, working pressure of 1-5 Pa, deposition time of 3-5 min, substrate temperature of 100-400 ℃, one group of working atmosphere being pure Ar gas, the other group of working atmosphere being Ar gas and O₂Gas, Ar/O₂The flow rate is 25sccm when the ratio is 1: 1; will deposit SnO₂And placing the glass substrate of the buffer layer in an annealing furnace, and annealing at 400-500 ℃ for 20-40 min in an air atmosphere.

1. SnO₂Setting the distance between the target and a substrate (FTO conductive glass) to be 8-10 cm, setting the working pressure to be 1-5 Pa, the working atmosphere to be Ar, the flow to be 25sccm, the substrate temperature to be 100 ℃, the sputtering power of a radio frequency power supply to be 100W, respectively depositing for 3min, 5min, 10 min and 15min to obtain four groups of samples, wherein the surface roughness of the four groups of samples is shown in the table I:

watch 1

SnO at 3min and 5min as shown in figure 4₂The film has 80% transmittance, and thicker SnO with the increase of deposition time₂More photons are absorbed inside the film, which in turn leads to SnO₂The transmittance of the film is gradually reduced, and when the deposition time is 15min, the transmittance of the sample is reduced to about 70%.

2. The above analysis shows that SnO obtained by deposition for 3min₂The film has the minimum roughness and the optimal transmittance, so the deposition time is unified to be 3min when selecting, and in order to further explore the influence of the change of the substrate temperature on the film performance, the adopted process parameters are as follows: working air pressure is 1Pa, sputtering power of a radio frequency power supply is 100W, the distance from a target to a substrate is 8-10 cm, and deposition is carried out for 3min at the substrate temperature of 100, 200, 300 and 400 ℃ respectively to obtain four groups of samples. SnO prepared at different substrate temperatures₂The surface roughness and the battery parameters of the film are respectively shown in the second table and the third table:

watch two

Watch III

FIG. 5 shows SnO deposited at a substrate temperature of 100 deg.C, 200 deg.C, 300 deg.C, 400 deg.C for 3min₂The transmission spectrum of the film, as can be seen from the graph, the film does not change much in the ultraviolet and visible light bands with the change of temperature, and the transmittance is about 80%, wherein SnO is deposited at 400 DEG C₂The reason why the film transmittance is slightly better than other temperatures may be SnO prepared at 400 deg.C₂The roughness of the film is small, the scattering effect of the incident light after reaching the film is reduced, and the transmittance of the film in ultraviolet and visible light wave bands is slightly increased. However, the transmittance of all samples is about 80% in the visible light band and the basic absorption edge is about 335nm in the whole view, so that the optical transmission requirement of the buffer layer of the thin-film solar cell is met.

3. The above analysis shows that the photoelectric efficiency of the film prepared at 100 ℃ is the highest, which indicates that the film prepared at 100 ℃ is the best process parameter. The metal oxide has certain oxygen deficiency in the preparation process to generate oxygen vacancy, so the following preparation process parameters are adopted: the sputtering power is 100W, the working pressure is 1Pa, the deposition time is 3min, and the substrate temperature is 100 ℃. One group of working atmosphere is pure Ar gas, the flow rate of Ar is 25sccm, and the other group of working atmosphere is Ar gas and O₂Gas, Ar/O₂Two sets of samples were prepared with a ratio of 1:1, and the surface roughness and cell parameters are shown in tables four and five:

watch four

Watch five

From the above table it can be seen that SnO prepared in an oxygen-containing atmosphere₂The film had less roughness and smoother surface, and at the same time, as shown in FIG. 7The oxygen atmosphere also fills up SnO in the preparation process₂The oxygen vacancy defect in the film body enables the current carrier to be captured by the oxygen vacancy less in the transmission process, thereby improving the open-circuit voltage and the short-circuit current and improving the battery efficiency.

4. The results of the above process research and the device preparation show that the SnO is further optimized₂The properties of the film may improve device efficiency. Annealing at 400 deg.C, 450 deg.C, and 500 deg.C for Ar/O₂SnO prepared under atmosphere₂Film annealing treatment for half an hour to prepare SnO₂The film contains certain oxygen vacancy, so the annealing modification is selectively carried out in the air, and FIG. 9 shows SnO under different treatment modes₂Film SEM topography, SnO without annealing treatment₂The uniformity of the grain size on the surface of the film is poor, the quality of a p-n junction can be seriously influenced by larger-sized grains, and SnO is annealed₂The surface of the film is more uniform, wherein after annealing at 450 ℃, the grain size of the film is most uniform, the film has almost no larger-size grains, the surface is smooth and compact, and SnO obtained by annealing at 500 ℃ is₂The film can see that some grains are agglomerated, and the agglomerated grains can cause the bonding quality of the interface to be poor and generate more interface defects. Thus, the present invention selects SnO prepared under oxygen atmosphere at 450 deg.C₂The film was annealed, and the battery parameters are shown in table six:

watch six

From the above analysis, SnO₂The optimal preparation process parameters of the buffer layer are that the deposition time is 3min, the substrate temperature is 100 ℃, and the sputtering atmosphere is Ar/O₂Annealing at 450 deg.C for 30min in air atmosphere at 1: 1. (3) Sb₂Se₃Preparing a light absorption layer:

preparing antimony selenide film by using OTF-1200X-RTP-II close-space sublimation furnace of mixed-fertilizer crystal, and mounting stone on upper heating table of sublimation furnace chamberInk mask, mounting AlN ceramic plate on the lower heating stage, and setting antimony selenide growth source on the AlN ceramic plate; depositing SnO₂The glass substrate of the buffer layer is arranged on the graphite mask and is arranged opposite to the antimony selenide growth source, the distance between the glass substrate and the antimony selenide growth source is 4-5 mm, and the chamber is closed; vacuumizing a sublimation furnace chamber to 1-5 Pa, introducing 100Pa high-purity Ar gas, vacuumizing to 1-5 Pa, repeating the operation until residual air in the sublimation furnace chamber is removed, and stabilizing the gas pressure in the sublimation furnace chamber to 5 Pa; raising the temperature of an antimony selenide growth source to 450-480 ℃, keeping the substrate temperature at 250 ℃, and growing for 3600-7200S in SnO₂And an antimony selenide film is grown on the upper surface of the buffer layer. Prepared Sb₂Se₃And respectively carrying out in-situ annealing and selenization annealing on the thin film. In-situ annealing refers to the reaction of Sb obtained by a close space sublimation method₂Se₃Cooling the film to room temperature along with the furnace, and then heating an upper heating table and a lower heating table of the sublimation furnace to 325-375 ℃ for in-situ annealing for 20-40 min; selenization annealing refers to the production of Sb by close-space sublimation₂Se₃Cooling the film to room temperature along with the furnace, and then cooling Sb on the AlN ceramic plate₂Se₃And taking out the sublimation source, replacing and placing the sublimation source into the Se sublimation source, and then simultaneously heating the upper heating table and the lower heating table to 325-375 ℃ for 20-40 min.

1. The fixed source base distance is 4-5 mm, different source temperature parameters are set, the temperature gradient is 30 ℃, the temperature is 440 ℃, 470 ℃, 500 ℃ and 530 ℃, respectively, and the substrate is kept at 250 ℃ to deposit Sb₂Se₃Films, four samples were obtained with cell parameters as shown in table seven:

watch seven

As shown in the above table, Sb prepared at 470 deg.C₂Se₃The thin-film solar cell is best, and the device has higher photoelectric conversion efficiency of 2.33%.

2. In order to obtain more excellent battery performance, more crystallinity is requiredGood film and high quality p-n junction interface, therefore, the film is required to be annealed, and the annealing parameters are as follows: annealing at 350 deg.C for 30min, and in-situ annealing and selenizing annealing respectively, wherein the in-situ annealing is carried out by furnace cooling to room temperature after film deposition, and then heating to set temperature for annealing, and the selenizing annealing is carried out by annealing prepared Sb₂Se₃The film is put into a chamber with a selenium source, and is heated to a set temperature to anneal in a selenium atmosphere, wherein the annealing is carried out in a near-space sublimation furnace. Annealing samples, selecting Sb prepared under the optimal parameter of 470 DEG C₂Se₃And the change of the performance of the thin film is researched through different annealing treatments, and the influence of the change on the performance of the solar cell device is analyzed. Sb after different annealing treatments₂Se₃The surface roughness and battery parameters of the film are shown in table eight and table nine:

table eight

Watch nine

FIG. 15 is Sb₂Se₃The comparison of the surface appearance of the film SEM shows that the grain shape is sharp before annealing and a small amount of pores exist among the grains, the pores can block the transmission of current carriers to reduce the performance of the device, and the Sb is annealed in situ or selenized₂Se₃The film surface porosity was significantly reduced, the film was denser, and the grains were more rounded, which is also consistent with the AFM results herein. More rounded crystal grains and Sb with higher density₂Se₃The film and the n-type buffer layer form a high-quality p-n junction, so that collection and separation of photon-generated carriers are more efficient.

Sb after in-situ annealing at 350 DEG C₂Se₃The peak position of the film population remains unchanged and the abundance of the (hk1) crystallographic planes is improvedThe maximum peak of the film is still (221), while the maximum peaks of the film after selenization annealing at 350 ℃ are (221) and (211), the abundance of the (hk0) crystal face is reduced, the peaks including (120), (230) and (240) are obviously weakened, and the number of the mixed peaks is less, as shown in figure 17, and the selenization annealing at 350 ℃ fills up a certain selenium vacancy to obtain Sb₂Se₃The film was more dense, indicating that the introduction of the selenium atmosphere acted positively. The finally obtained solar cell parameter is V_OC＝274mV，J_SC＝28.25mA/cm²，FF＝36.61％，PCE＝2.83％。

From the above analysis, Sb was found to be₂Se₃The optimal preparation process of the light absorption layer comprises the steps of fixing the source base distance to be 5mm, controlling the temperature of the lower heating table to be 250 ℃, controlling the temperature of the upper heating table to be 470 ℃, depositing for 3600S, and finally performing selenization annealing at 350 ℃ for 30 min.

(5) Preparing an electrode:

the invention adopts a multifunctional surface processor SBC-2-1 vacuum evaporation plating instrument of a Chinese medical science instrument to prepare the gold electrode, and comprises the following steps,

and opening a main power supply, recovering the interior of the chamber to an atmospheric pressure state, taking down the quartz cover, and loading the evaporation boat (tungsten boat) and the mask plate to fixed positions. The mask is positioned right above the evaporation boat to ensure the uniformity of the thickness of the evaporated electrode of each sample. Respectively placing the sample and gold particles into the through hole of mask plate and evaporation boat, covering with quartz cover, starting to vacuum-pumping until the vacuum degree is 5X 10^-3pa. And turning on an evaporation power supply, slowly adjusting the current to be increased to 75A, keeping for 3min when the evaporation current is 75A, and slowly adjusting the current to be 0A after the gold solution on the evaporation boat is evaporated. Turning off the evaporation power supply, and continuing to vacuumize to 5 × 10^-3pa. And then closing the vacuum pump, opening the air release valve, taking off the quartz cover after 5min, taking out the sample, and finishing evaporation.