Annealing equipment suitable for large-area perovskite film layer

Abstract

The utility model belongs to the field of photovoltaic technology, and relates to annealing equipment suitable for a large-area perovskite film layer, which comprises an annealing chamber, a heating mechanism, a hot air circulating mechanism and a product carrying mechanism, the hot air circulation mechanism comprises an air uniformizing plate and an air guide plate, an air return channel is formed in the outer side of the air guide plate, the annealing chamber is divided into an upper cavity and a lower cavity by the air uniformizing plate, the product carrying mechanism is located in the upper cavity and supports the photovoltaic module, and the heating mechanism is located in the lower cavity; the product carrying mechanism is hollow so that the middle part of the lower surface of the photovoltaic module is exposed. According to the equipment, the film coating surface of the glass substrate can face downwards and is directly heated by hot air, so that the whole perovskite film can reach a preset temperature in a very short time, the film layer rapidly reaches a supersaturation condition, the heat utilization rate is remarkably improved, perovskite nucleation is accelerated, the nuclear density is improved, the film layer crystallization quality is improved, and the service life of the film layer is prolonged. Therefore, the overall photoelectric conversion efficiency of the perovskite cell is improved, and the method is better in applicability to a large-area perovskite photovoltaic module.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, and particularly relates to an annealing device suitable for large-area perovskite film layers. Background Art

[0002] Organic-inorganic hybrid perovskite solar cells have attracted much attention in the academic and industrial fields due to their high photoelectric conversion efficiency and low production cost. Their excellent optoelectronic properties are mainly attributed to the high light absorption coefficient, high carrier mobility, long carrier lifetime, adjustable bandgap and other characteristics of such perovskite materials; and they can be mass-produced based on solution processing methods, which greatly reduces the production cost and quickly makes them a new star in new thin-film solar cells, and their future development is highly expected by the market. However, the perovskite thin films prepared by existing process technologies have a high number of grain boundaries and defect density. More importantly, with the increase of the substrate area, the quality problems of the thin films will increase significantly, seriously affecting the optoelectronic performance and service life of the battery devices. The annealing crystallization process is a crucial link affecting the quality of perovskite thin films. This process regulates the nucleation and crystal growth of perovskite thin films through rapid heating and temperature uniformity, directly determining the generation and transport process of carriers in the perovskite light absorption layer, and is the basis for obtaining large-area and high-efficiency perovskite solar cell devices. Currently, the common annealing crystallization devices are generally direct-contact heating annealing furnaces and non-contact annealing furnaces.

[0003] The direct-contact heating annealing furnace is the most common heating device at present, such as a flat heating table, which is widely used in laboratory-level research. Its advantages are low cost, fast heating and small floor area; however, with the increase of the perovskite substrate area, the area of the directly contacted flat heating table also needs to increase accordingly, and a variety of problems are difficult to solve:

[0004] 1. It is difficult to ensure the uniformity of large-area flat heating. The larger the flat area, the worse the temperature uniformity, and the more obvious the temperature difference between the middle and edge regions.

[0005] 2. The annealing crystallization process requires a certain time course, generally ranging from 15 to 30 minutes. A flat heating table can only anneal one perovskite product at a time, and the production capacity is severely limited. To solve this problem, a multi-layer structure needs to be adopted, and each layer has a separate heating flat, resulting in relatively high energy consumption and cost.

[0006] 3. More critically, although direct-contact heating has the advantage of rapid heating of the glass substrate, there is a problem of warping and deformation of the photovoltaic glass substrate when it comes to large-area perovskite devices. This directly causes uneven heating of the perovskite film layers on different parts of the same substrate, inconsistent crystallization processes, and affects the film layer quality.

[0007] The non-contact annealing furnace heats the perovskite film layer by means of lamp tube infrared heating or suspending the heated substrate, and mainly transfers heat through thermal radiation and convection. Sometimes there is also a transmission module, which not only ensures the temperature uniformity and improves the crystallization quality of the perovskite film, but also solves the problems of limited production capacity and large-area substrates. In this regard, the non-contact annealing furnace is an ideal annealing equipment for the absorption layer of large-area perovskite solar cells. However, the existing non-contact annealing furnace still has the key problem of slow substrate heating. Specifically, there are two situations for the drying of the perovskite precursor solution on the substrate:

[0008] 1. If the solvent evaporates slowly, the concentration will remain between the critical concentration and the saturation concentration; the crystal keeps growing, but no more nuclei are generated until all the solvent is removed. At this time, only a small number of nuclei on the substrate surface grow in an island shape; this type of crystal growth cannot completely cover the substrate and will produce many defects in the final perovskite film.

[0009] 2. When the solvent evaporates and dries quickly, the concentration remains above the critical concentration; nuclei will continuously be generated in the precursor solution on the substrate until there is no more space on the substrate to accommodate further nuclei, thus forming a uniform and dense perovskite layer; at this time, the crystal size is small and grows into crystals with a larger average size through Ostwald ripening.

[0010] In short, annealing the perovskite precursor solution at a high temperature in a short time can induce the removal of the solvent to establish a supersaturated condition, accelerate perovskite nucleation and increase the nucleation density. However, non-contact heating only relies on radiation and convection to heat the photovoltaic glass substrate (industrial-grade photovoltaic glass thickness 3.2 mm), and then anneals the perovskite layer through heat conduction. In this way, the heating rate of the perovskite film is slow, and it is easy to miss the best window period for perovskite crystallization annealing, resulting in more grain boundaries and defects. Currently, the commonly used measure is over-temperature treatment of the heating unit, that is, assuming the perovskite annealing condition is 150 °C, the initial temperature of the annealing furnace is set to 190 °C or even higher to achieve the purpose of increasing the heating rate. However, the perovskite material is too sensitive to high-temperature conditions and is difficult to control. Over-temperature treatment is extremely likely to damage the film layer material itself and cause more defects.

[0011] Therefore, it is necessary to design an annealing equipment specifically suitable for large-area perovskite film layers to solve the above problems. Summary of the Invention

[0012] The main purpose of the present invention is to provide an annealing equipment suitable for large-area perovskite film layers, which can enable the entire perovskite film to reach the preset temperature in a very short time and improve the crystallization quality of the film layer.

[0013] The present utility model realizes the above object through the following technical solutions: An annealing device applicable to a large-area perovskite film layer, comprising an annealing chamber, a heating mechanism, a hot air circulation mechanism, and a product carrying mechanism;

[0014] The hot air circulation mechanism includes an air distribution plate located in the middle of the annealing chamber and a wind guiding plate located around the air distribution plate. The outside of the wind guiding plate is a return air channel. The air distribution plate divides the annealing chamber into an upper chamber and a lower chamber. The product carrying mechanism is located in the upper chamber and holds the photovoltaic module, and the heating mechanism is located in the lower chamber;

[0015] The product carrying mechanism holds the edge of the photovoltaic module. The product carrying mechanism is hollow so that the middle part of the lower surface of the photovoltaic module is exposed, and the exposed part faces the air distribution plate.

[0016] Specifically, a fan is provided in the return air channel, and the fan makes air pass through the return air channel from top to bottom.

[0017] Specifically, the heating mechanism is a heating plate located at the bottom of the lower chamber.

[0018] Specifically, the supporting width of the product carrying mechanism is not less than 5 mm.

[0019] Specifically, the material of the supporting part of the product carrying mechanism is polytetrafluoroethylene.

[0020] The beneficial effect of the technical solution of the present utility model is:

[0021] This device can make the coating surface of the glass substrate face downward and directly receive the heating of hot air, so that the entire perovskite thin film can reach the preset temperature in a very short time, the film layer quickly reaches the supersaturated condition, significantly improves the thermal utilization rate, accelerates perovskite nucleation and increases the nucleation density, improves the crystallization quality of the film layer, and further improves the overall photoelectric conversion efficiency of the perovskite battery, and has better applicability to large-area perovskite photovoltaic modules. Description of the Drawings

[0022] Figure 1 It is a working state diagram of the annealing device of this embodiment.

[0023] The numbers in the figure represent:

[0024] 1 - annealing device, 11 - annealing chamber, 111 - upper chamber, 112 - lower chamber, 113 - return air channel, 12 - heating mechanism, 13 - hot air circulation mechanism, 131 - air distribution plate, 132 - wind guiding plate, 133 - fan, 14 - product carrying mechanism;

[0025] 2 - photovoltaic module, 21 - glass substrate, 22 - perovskite film layer. Detailed Embodiments

[0026] The present utility model will be further described in detail below in conjunction with specific embodiments.

[0027] Embodiment:

[0028] As Figure 1 shown, the annealing device 1 for a large-area perovskite film layer of the present utility model includes an annealing chamber 11, a heating mechanism 12, a hot air circulation mechanism 13, and a product carrier mechanism 14.

[0029] As Figure 1 shown, the hot air circulation mechanism 13 includes an air distribution plate 131 located in the middle of the annealing chamber 11 and a wind guide plate 132 located around the air distribution plate 131. The outside of the wind guide plate 132 is a return air channel 113. The air distribution plate 131 divides the annealing chamber 11 into an upper chamber 111 and a lower chamber 112. The product carrier mechanism 14 is located in the upper chamber 111 and holds the photovoltaic module 2. The heating mechanism 12 is located in the lower chamber 112. A fan 133 is provided in the return air channel 113, and the fan 133 causes air to pass through the return air channel 113 from top to bottom.

[0030] The hot air circulation mechanism 13 can make air circulate in the annealing chamber 11. The air in the lower chamber 112 becomes less dense after being heated by the heating mechanism 12 and will pass upward through the air distribution plate 131, and the air distribution plate 131 makes the wind speed uniform; when the hot air reaches the upper chamber 111, it will directly contact the bottom of the photovoltaic module 2. Since the photovoltaic module 2 is placed with the glass substrate 21 on top and the perovskite film layer 22 on the bottom at this time, the hot air can directly transfer heat to the perovskite film layer 22 to anneal it; after the heat of the hot air is lost, its density increases, and it will return to the lower chamber 112 from the return air channels 113 on both sides and then be reheated, forming a cycle of hot air. The fan 133 is used to promote the circulation of hot air, and being provided in the return air channel 113 can make the flow condition of air relatively stable. The design of the hot air circulation mechanism 13 can ensure the fluidity of the circulating hot air in the annealing chamber 11, avoid the retention of organic solvents on the surface of the perovskite film layer 22, and at the same time can also ensure the cleanliness of the air flow in the annealing chamber 11, avoid the contamination of the film surface by dust and impurities, etc., resulting in film layer defects and causing defect recombination in the carrier transport process.

[0031] As Figure 1 shown, the heating mechanism 13 is a heating plate located at the bottom of the lower chamber 112.

[0032] The heating plate heats the air through the entire upper surface, making the air flow in the lower chamber 112 relatively uniform, so that the air distribution effect of the air distribution plate 131 is better.

[0033] As Figure 1As shown, the product supporting mechanism 14 supports the edge of the photovoltaic module 2, and the supporting width is not less than 5 mm. The product supporting mechanism 14 is hollow to expose the middle part of the lower surface of the photovoltaic module 2, and the exposed part faces the air distribution plate 111.

[0034] After being heated by the heating mechanism 13, the hot air immediately passes through the air distribution plate 131 to reach the photovoltaic module 2. The heating temperature of the heating mechanism 13 is basically equal to the temperature at which the hot air contacts the perovskite film layer 22, so the control is simple. The entire perovskite thin film can reach the preset temperature in a very short time, the film layer quickly reaches the supersaturated condition, significantly improves the thermal utilization rate, accelerates perovskite nucleation and increases the nucleation density, improves the crystallization quality of the film layer, and further improves the overall photoelectric conversion efficiency of the perovskite battery, and has better applicability to large-area perovskite photovoltaic modules. In order to place the photovoltaic module 2 stably on the product supporting mechanism 14, there must be enough supporting space, and the problem of increased deformation due to the large area of the photovoltaic module 2 should also be avoided. However, the supporting range should not be too large, which will reduce the area facing the hot air and affect the light conversion efficiency at the edge position after the battery chip is made. Therefore, usually 5 mm can ensure that the photovoltaic module 2 does not fall off, and at the same time, the width of the contact between the perovskite film layer 22 and the product supporting mechanism 14 is less than the width of the clear edge of the battery chip.

[0035] The material of the supporting part of the product supporting mechanism 14 is polytetrafluoroethylene.

[0036] When the photovoltaic module 2 is placed upside down, the perovskite film layer 22 will contact the supporting part, and the hot air flowing from bottom to top will also preferentially contact the supporting part of the product supporting mechanism 14. Therefore, it is necessary to ensure that the supporting part is durable at high temperatures, avoid being corroded by the solvent in the perovskite, and prevent the problem of uneven heating of the photovoltaic module 2 caused by too fast heating of the supporting part. Polytetrafluoroethylene is a material that is relatively high-temperature and corrosion-resistant, and has a low thermal conductivity, so polytetrafluoroethylene is preferably used as the material of the supporting part here.

[0037] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. An annealing device suitable for large-area perovskite film layers, characterized in that: It includes an annealing chamber, a heating mechanism, a hot air circulation mechanism and a product supporting mechanism; The hot air circulation mechanism includes an air distribution plate located in the middle of the annealing chamber and an air guide plate located around the air distribution plate, the outer side of the air guide plate is a return air channel, the air distribution plate divides the annealing chamber into an upper chamber and a lower chamber, the product supporting mechanism is located in the upper chamber and supports the photovoltaic module, and the heating mechanism is located in the lower chamber; The product supporting mechanism supports the edge of the photovoltaic component. The product supporting mechanism is hollow so that the middle part of the lower surface of the photovoltaic component is exposed, and the exposed part faces the wind equalizing plate.

2. The annealing device for large-area perovskite film according to claim 1, characterized in that: A fan is arranged in the return air passage, and the fan allows air to pass through the return air passage from top to bottom.

3. The annealing device for large-area perovskite film according to claim 1, characterized in that: The heating mechanism is a heating plate located at the bottom of the lower chamber.

4. The annealing device for large-area perovskite film according to claim 1, characterized in that: The supporting width of the product supporting mechanism shall not be less than 5 mm.

5. The annealing device for large-area perovskite film according to claim 1, characterized in that: The supporting part of the product supporting mechanism is made of polytetrafluoroethylene.

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