Annealing method and annealing device

Abstract

The invention discloses an annealing method and an annealing device.The annealing method comprises the steps that heating modules are arranged on the bottom face and the top face of an annealing chamber so that a thermal field can be formed in the annealing chamber; the coating body is suspended between the two heating modules; hot inert gas is introduced into the annealing chamber, so that the hot inert gas flows through the upper surface of the coating body; and the hot inert gas flowing through the upper surface of the coating body is pumped out, so that the solvent steam in the annealing chamber is taken away through airflow. According to the annealing method and the annealing device, an isothermal thermal field can be maintained, deformation of a substrate of a coating body caused by direct contact of a heat source with the coating body can be avoided, and the uniformity of the thermal field can be prevented from being disturbed by low-temperature inert gas, so that the annealing effect is improved; and the problem of solvent steam retention can be weakened or avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of annealing, in particular to an annealing method and an annealing device. BACKGROUND

[0002] The annealing crystallization process of the film layer structure is a key link to determine the photoelectric performance of the thin film, especially in the thin film prepared by the solution method such as perovskite, solvent volatilization and crystal directional growth need to be realized through annealing. However, in the industrialized production facing large-area (such as square meter level) substrate, the traditional annealing technology has technical bottlenecks.

[0003] The existing equipment mostly adopts the contact type hot plate annealing scheme:

[0004] The lower heating module scheme: rely on the direct contact between the substrate and the hot plate to conduct heat. Due to the poor thermal conductivity of the glass substrate and the mismatch of the thermal expansion coefficient, the uneven heating causes local temperature difference, resulting in the formation of "flower face" (i.e. the mixture of crystalline region and amorphous region) of perovskite thin film, which significantly reduces the photoelectric conversion efficiency of the thin film.

[0005] The upper heating module scheme: avoid contact deformation through radiation heating, but the solvent vapor volatilized in the annealing will interfere with the radiation heat transfer, causing the temperature gradient of the thin film surface to change sharply, resulting in "fog face", which affects the light transmittance and mechanical stability of the thin film.

[0006] In addition, in order to take away the solvent vapor, the existing technology needs to introduce inert gas. However, directly introducing inert gas at room temperature (23℃) forms a sharp temperature difference with the high temperature environment (>100℃) of the annealing chamber, causing the local cooling of the substrate, inducing the cracking of the thin film. At the same time, the direct gas charging method is easy to form turbulent flow area, which disturbs the uniformity of the heat field; uneven gas flow distribution makes the solvent vapor stay in the chamber, hinders the directional growth of the crystal and induces secondary condensation, causing the composition segregation of the thin film.

[0007] In order to solve at least one of the above technical problems, the present application provides an annealing method and an annealing device. SUMMARY

[0008] The purpose of the present application is to provide an annealing method and an annealing device, which can maintain an isothermal heat field, avoid the direct contact between the heat source and the coated body to cause the deformation of the substrate of the coated body, and also avoid the disturbance of the low-temperature inert gas to the uniformity of the heat field, so as to improve the effect of annealing; and can weaken or avoid the problem of solvent vapor retention.

[0009] The purpose of the present application is achieved by adopting the following technical solutions:

[0010] On the one hand, the present application provides an annealing method, comprising the following steps:

[0011] The heating module is arranged on the bottom surface and the top surface of the annealing chamber to form a heat field in the annealing chamber;

[0012] suspension of the coated body between two heating modules;

[0013] passing hot inert gas into the annealing chamber, so that the hot inert gas flows over the upper surface of the coated body;

[0014] extracting the hot inert gas after flowing over the upper surface of the coated body to remove solvent vapor in the annealing chamber by air flow.

[0015] The beneficial effects of the above scheme are that the present application forms a thermal field by synchronous heating of the bottom surface and the top surface, eliminates the temperature difference of the substrate caused by traditional single-sided heating, and prevents cracks or crystallization defects of the coating material due to uneven heating. By suspending the coated body, the contact heat conduction path is cut off, only the radiation heat transfer and the hot gas convection are reserved, and the temperature fluctuation caused by the thermal deformation of the substrate of the coated body is prevented from the root; by passing the hot inert gas, the uniformity of the thermal field can be avoided, and the local rapid cooling of the coated body caused by the low-temperature inert gas is avoided; by directly extracting the hot inert gas after flowing over the upper surface of the coated body, a one-way air flow path is formed, solvent vapor is quickly removed, and secondary condensation of the vapor is avoided.

[0016] Further, the passing of the hot inert gas into the annealing chamber comprises:

[0017] one or more first cavities are arranged on the bottom surface;

[0018] The gas input assembly is used for inputting the hot inert gas into the first cavity.

[0019] A first porous structure is arranged on the gas outlet side of each first cavity, and the hot inert gas enters the annealing chamber through the first porous structure, flows around the lower surface of the coated body, and flows to the upper surface of the coated body.

[0020] The beneficial effects of the above scheme are that the present application makes the hot inert gas uniformly diffuse through the first porous structure, forms laminar flow covering the lower surface of the coated body, and reduces turbulent flow interference.

[0021] Further, the gas input assembly for inputting the hot inert gas into the first cavity comprises:

[0022] The temperature of each region of the coated body is collected.

[0023] If the temperature of any region is less than the annealing temperature, the temperature of the hot inert gas in the gas input assembly corresponding to the region is increased.

[0024] if the temperature difference of any region and the average temperature of the coated body is greater than or equal to the first threshold value, then the temperature of the hot inert gas in the gas input assembly corresponding to the region is adjusted to make the temperature of the region greater than or equal to the annealing temperature and the temperature difference with the average temperature of the coated body less than the first threshold value;

[0025] wherein the first threshold value is determined based on the characteristics of the coating material on the coated body.

[0026] The above scheme has the beneficial effect that the present application compensates for the heating of the low-temperature region of the coated body by partitioning, to prevent local insufficient solidification; the temperature of the region is corrected by temperature difference overrun, which can eliminate hot / cold spots to ensure the consistency of the annealing process.

[0027] Further, the gas input assembly for inputting hot inert gas into the first cavity comprises:

[0028] acquiring the airflow velocity on the upper surface of the coated body;

[0029] if the airflow velocity is greater than or equal to the flow velocity limit value, then the gas flow of the gas input assembly is reduced;

[0030] wherein the flow velocity limit value is determined based on the viscosity threshold value of the coating material on the coated body.

[0031] The above scheme has the beneficial effect that the present application controls the airflow velocity on the upper surface of the coated body to prevent high-viscosity coating material on the substrate from being washed and deformed by the airflow, or blown away from the substrate.

[0032] Further, the gas input assembly for inputting hot inert gas into the first cavity comprises:

[0033] acquiring the first pressure difference between the first side of the first porous structure and the second side thereof;

[0034] if the first pressure difference is greater than or equal to the first preset threshold value, then a first alarm signal is triggered and the gas flow of the gas input assembly is reduced;

[0035] wherein the first preset threshold value is determined based on the porosity of the first porous structure.

[0036] The above scheme has the beneficial effect that the present application detects the clogging condition of the first porous structure to avoid uneven distribution of the hot inert gas input into the annealing chamber.

[0037] Further, the hot inert gas after flowing through the upper surface of the coated body comprises:

[0038] one or more second cavities are arranged on the top surface;

[0039] Each of the second cavities is provided with a second porous structure on the suction side, which communicates with the annealing chamber to introduce the hot inert gas into the second cavity;

[0040] Each of the second cavities is provided with a second porous structure on the suction side, which communicates with the annealing chamber to introduce the hot inert gas into the second cavity;

[0041] The above scheme has the beneficial effect that the second porous structure is used to realize uniform suction or partitioned uniform suction, avoiding local airflow that is too strong to cause uneven heating of the coated body or disturbance to the coating material.

[0042] Further, the gas output assembly for discharging the hot inert gas from the second cavity includes:

[0043] Collecting the airflow velocity on the upper surface of the coated body;

[0044] If the airflow velocity is greater than or equal to the flow velocity limit value, the gas flow of the gas output assembly is reduced;

[0045] The flow velocity limit value is determined based on a viscosity threshold of the coating material on the coated body.

[0046] The above scheme has the beneficial effect that the airflow velocity on the upper surface of the coated body is controlled to prevent high-viscosity coating material on the substrate from being washed and deformed by the airflow or blown away from the substrate.

[0047] Further, the gas output assembly for discharging the hot inert gas from the second cavity includes:

[0048] Obtaining a second pressure difference between the inside and outside of the annealing chamber;

[0049] If the second pressure difference is greater than 0 and the pressure difference is greater than or equal to a second preset threshold, the gas flow of the gas output assembly is increased;

[0050] If the second pressure difference is greater than 0 and the pressure difference is less than the second preset threshold, the gas flow of the gas output assembly is reduced;

[0051] If the second pressure difference is less than or equal to 0, a second alarm signal is triggered and the gas flow of the gas output assembly is reduced;

[0052] The second preset threshold is determined based on the porosity of the second porous structure.

[0053] The above scheme has the beneficial effect that the annealing chamber is maintained at a positive pressure to prevent external air from backflowing and contaminating.

[0054] Further, the gas output assembly for discharging the hot inert gas from the second cavity includes:

[0055] obtaining a flow difference between the gas input assembly and the gas output assembly;

[0056] if the flow difference is greater than a first stagnation threshold, increasing a gas flow of the gas output assembly corresponding to the top surface peripheral region;

[0057] wherein the first stagnation threshold is determined based on the annealing chamber volume.

[0058] The beneficial effects of the above-mentioned solution are that, by linkage with the gas output assembly, the present application can inhibit the scouring of the coating material by excessively high flow rate, so that the coating material is deformed or separated from the substrate.

[0059] In another aspect, the present application provides an annealing device, comprising:

[0060] an annealing chamber, a bottom surface of the annealing chamber being provided with one or more first porous structures, each of the first porous structures being communicated with at least one gas input assembly for providing hot inert gas; a top surface of the annealing chamber being provided with one or more second porous structures, each of the second porous structures being communicated with at least one gas output assembly for discharging the hot inert gas;

[0061] a coating body suspended in the annealing chamber;

[0062] a controller for controlling the gas input assembly and the gas output assembly to perform the steps of the above-mentioned annealing method.

[0063] Compared with the prior art, the beneficial effects of the present application at least include:

[0064] The annealing method and the annealing device of the present application can maintain an isothermal thermal field, can avoid the direct contact of the heat source with the coating body to cause the deformation of the substrate of the coating body, can also avoid the disturbance of the low-temperature inert gas to the uniformity of the thermal field, so as to improve the annealing effect, and can weaken or avoid the problem of solvent vapor stagnation. Specifically, the thermal field is formed by synchronous heating of the bottom surface and the top surface, the temperature difference of the substrate caused by traditional single-surface heating is eliminated, and the cracks or crystallization defects of the coating material caused by uneven heating are prevented; the coating body is suspended, the contact type heat conduction path is cut off, only the radiation heat transfer and the hot gas convection are reserved, and the temperature fluctuation caused by the thermal deformation of the substrate of the coating body is prevented from the root; the hot inert gas is introduced, the disturbance of the low-temperature inert gas to the uniformity of the thermal field is avoided, and the local rapid cooling of the coating body is caused; the hot inert gas is directly extracted after flowing through the upper surface of the coating body, a one-way airflow path is formed, the solvent vapor is quickly taken away, and the secondary condensation of the vapor is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1is a flowchart of the annealing method of the embodiment of the present application.

[0066] Figure 2 is a structural diagram of an annealing chamber of the embodiment of the present application.

[0067] Figure 3 is another structural diagram of an annealing chamber of the embodiment of the present application.

[0068] Figure 4 is a structural diagram of a substrate of the embodiment of the present application.

[0069] Figure 5 is a structural diagram of a heat preservation shell of the embodiment of the present application.

[0070] Figure 6 is a structural diagram of a gas input assembly of the embodiment of the present application.

[0071] Figure 7 is a structural diagram of a first porous structure of the embodiment of the present application.

[0072] Figure 8 is a structural diagram of a second porous structure of the embodiment of the present application.

[0073] Figure 9 is another structural diagram of a substrate of the embodiment of the present application.

[0074] Figure 10 is a UV-Vis absorption spectrum diagram of Example 1 and Comparative Example 1 of the embodiment of the present application.

[0075] Figure 11 is a 9-point absorption spectrum overlapping comparison diagram of Example 1 of the embodiment of the present application.

[0076] In the figure: 1, heat preservation shell; 11, first side surface; 12, second side surface; 13, third side surface; 14, fourth side surface; 15, top side surface; 16, bottom side surface; 2, annealing chamber; 201, first chamber; 202, second chamber; 21, first surface; 22, second surface; 23, third surface; 24, fourth surface; 25, top surface; 26, bottom surface; 271, first porous structure; 272, second porous structure; 281, gas input assembly; 2811, gas input channel; 2812, first pressure reducing valve; 2813, first flow regulating valve; 2814, first flow meter; 2815, gas heater; 2816, first temperature sensor; 282, gas output assembly; 291, first cavity; 2921, first cavity; 2922, second cavity; 2923, third cavity; 31, first heating module; 311, first through hole; 312, first heating plate; 313, first rectifier plate; 32, second heating module; 321, second through hole; 322, second heating plate; 323, second rectifier plate; 4, coated body; 41, invalid area; 42, effective area; 421, sub-area; 4201, center area; 4202, transition area; 4203, edge area. DETAILED DESCRIPTION

[0077] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings; however, the example embodiments can be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the several views. Like components will not be repeatedly described with a repeated description omitted.

[0078] The words expressing position and direction described in the present application are described with reference to the drawings, but changes can be made according to needs, and the changes are included in the protection scope of the present application.

[0079] Reference Figure 1 The annealing method of the present application comprises steps SS1 to SS4.

[0080] Step SS1: heating modules are arranged on the bottom surface 26 and the top surface 25 of the annealing chamber 2 to form a thermal field in the annealing chamber 2.

[0081] In application, the two oppositely arranged heating modules jointly constitute the annealing chamber 2, which can be a hexahedral chamber or other shapes such as a heterohedral structure. Preferably, referring to Figure 2, the annealing chamber 2 is a hexahedral chamber, comprising oppositely arranged top surface 25 and bottom surface 26, oppositely arranged first surface 21 and second surface 22, and oppositely arranged third surface 23 and fourth surface 24. Among them, the top surface 25 and the bottom surface 26 are perpendicular to the first surface 21, the second surface 22, the third surface 23 and the fourth surface 24. The first surface 21, the third surface 23, the second surface 22 and the fourth surface 24 are sequentially connected end to end to form the side surface of the annealing chamber 2.

[0082] In practical application, referring to Figure 3 The first heating module 31 is arranged on the bottom surface 26 of the annealing chamber 2, and the second heating module 32 is arranged on the top surface 25 of the annealing chamber 2. Among them, the first heating module 31 can further include a first heating plate 312 and a first rectifier plate 313. The second heating module 32 can further include a second heating plate 322 and a second rectifier plate 323. The first heating plate 312 and the second heating plate 322 are used to heat the temperature of the annealing chamber 2 to provide environmental conditions for the annealing of the coated body 4. The first rectifier plate 313 and the second rectifier plate 323 are used for heat conduction and uniform heat field. In actual implementation process, the first heating plate 312, the first rectifier plate 313, the second heating plate 322 and the second rectifier plate 323 can be realized by using existing heating plate and rectifier plate, so the present application will not be described again.

[0083] In actual implementation process, the annealing chamber 2 can be provided with a heat preservation shell 1, and the heat preservation shell 1 covers the annealing chamber 2. The heat preservation shell 1 can be prepared from single layer material, double layer material or multi-layer material. Preferably, the heat preservation shell 1 is made of double layer stainless steel material.

[0084] Step SS2: suspending the coated body 4 between the two heating modules.

[0085] In practical application, referring to Figure 3 The coated body 4 is arranged in the annealing chamber 2 and suspended between the first heating module 31 and the second heating module 32, so as to divide the annealing chamber 2 into a first chamber 201 and a second chamber 202. Moreover, the first chamber 201 is close to the first heating module 31, and the second chamber 202 is close to the second heating module 32.

[0086] In practical application, the coated body 4 includes a substrate and a coating material. Among them, the substrate includes a lower surface and an upper surface, the lower surface faces the heating module of the bottom surface 26, the upper surface faces the heating module of the top surface 25, and the upper surface is coated with the coating material.

[0087] Further, referring to Figure 4The substrate includes an invalid area 41 and a valid area 42. The invalid area 41 is an outer edge of the substrate, and the width of the invalid area 41 is 5-20 mm. The valid area 42 is a central part of the substrate, and the area of the valid area 42 accounts for more than 90% of the total area of the substrate. The upper surface of the valid area 42 is coated with a coating material. Further, the valid area 42 can be equally divided into a plurality of sub-areas 421, and the plurality of sub-areas 421 are arranged in an array. Each sub-area 421 is provided with at least one temperature sensor (e.g., a thermocouple) to detect the temperature of the corresponding sub-area 421 in real time.

[0088] In addition, the coating material can be a layer structure or a perovskite precursor solution. The perovskite precursor solution includes a solvent and a solute. The solute is PbI2 and CH3NH3I. The solvent is selected from at least one of N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), gamma-butyrolactone (GBL), and isopropyl alcohol (IPA). The molecular formula of DMF is HCON(CH3)2, and the saturated vapor pressure at room temperature is 0.47 kPa. The molecular formula of DMSO is (CH3)2SO, and the saturated vapor pressure at room temperature is 0.08 kPa. The molecular formula of GBL is C4H6O2 (five-membered ring ester), and the saturated vapor pressure at room temperature is 0.2 kPa. The molecular formula of IPA is (CH3)2CHOH, and the saturated vapor pressure at room temperature is 5.87 kPa. The room temperature is generally 23°C.

[0089] In actual implementation, with reference to Figure 5 The heat preservation shell 1 includes a top side 15 and a bottom side 16 arranged oppositely, a first side 11 and a second side 12 arranged oppositely, and a third side 13 and a fourth side 14 arranged oppositely. The top side 15 and the bottom side 16 are perpendicular to the first side 11, the second side 12, the third side 13, and the fourth side 14. The first side 11, the third side 13, the second side 12, and the fourth side 14 are sequentially connected end to end to form a side wall of the heat preservation shell 1.

[0090] Further, opposite sides of the side wall of the heat preservation shell 1 (such as the first side 11 and the second side 12 arranged oppositely, or the third side 13 and the fourth side 14 arranged oppositely) are respectively provided with a first support and a second support. Specifically, the first side 11 extends to the center of the heat preservation shell 1 to form the first support, and the second side 12 extends to the center of the heat preservation shell 1 to form the second support. The first support and the second support are used to connect the ineffective area 41 of the substrate, so that the substrate is suspended between the two heating modules. Preferably, the length of the first support and the second support is less than the length of the first side 11 and the second side 12, and the first support and the second support are provided with a hollow structure, which can not only reduce the weight of the support, but also further enable the airflow of the first chamber 201 to communicate with the airflow of the second chamber 202.

[0091] Step SS3: introducing the hot inert gas into the annealing chamber 2, so that the hot inert gas flows through the upper surface of the coated body 4.

[0092] The temperature difference between the temperature of the hot field and the temperature of the hot inert gas is less than or equal to a first temperature threshold. The first temperature threshold can be determined based on the material properties of the coated body 4. The material properties of the coated body 4 include at least one of the thermal expansion coefficient of the substrate (such as the thermal expansion coefficient of the glass substrate being about 9x10 -6 / ℃), the elastic modulus of the substrate (such as the elastic modulus of the glass substrate being about 70GPa), the density of the substrate (such as the density of the glass substrate being about 2500kg / m 3 ), and the specific heat capacity of the substrate (such as the specific heat capacity of the glass substrate being about 840J / (kg·K)). In the implementation process, the thermal expansion coefficient of the substrate is preferably considered. For example, the first temperature threshold is preliminarily determined by the thermal expansion coefficient of the substrate, and is further corrected by the elastic modulus of the substrate.

[0093] The step SS3 of the present application includes steps SS311 to SS313.

[0094] Step SS311: providing one or more first cavities 291 on the bottom surface 26.

[0095] When a plurality of first cavities 291 are provided, the plurality of first cavities 291 are arranged in an array, and each first cavity 291 corresponds to at least one sub-area 421 of the substrate.

[0096] Step SS312: the gas inlet side of each first cavity 291 is communicated with at least one set of gas input assemblies 281, and the gas input assembly 281 is used to input the hot inert gas into the first cavity 291.

[0097] The gas input assembly 281 comprises a gas input channel 2811. The gas inlet end of the gas input channel 2811 is connected to a gas source, which can be an inert gas storage device comprising a storage tank connected to the gas inlet end of the gas input channel 2811 by a pipeline. The gas outlet end of the gas input channel 2811 is in communication with the first cavity 291.

[0098] With reference to Figure 6 The gas input channel 2811 is provided with at least one of a first pressure reducing valve 2812, a first flow regulating valve 2813, a first flow meter 2814, a gas heater 2815, and a first temperature sensor 2816. Preferably, the first pressure reducing valve 2812, the first flow regulating valve 2813, the first flow meter 2814, the gas heater 2815, and the first temperature sensor 2816 are arranged in sequence along the direction of flow of the inert gas in the gas input channel 2811. The first pressure reducing valve 2812 stabilizes the gas source pressure of the inert gas, buffers external gas supply fluctuations, and avoids sudden changes in the flow rate of the inert gas, which can cause sudden changes in the local temperature of the substrate. The first flow regulating valve 2813 is used to dynamically regulate the flow rate of the inert gas in the gas input channel 2811, for example, to 80 L / min to 120 L / min. The first flow meter 2814 is used to monitor the flow rate of the inert gas in real time and feed back to the first flow regulating valve 2813. The gas heater 2815 is used to heat the inert gas to 120°C to 150°C to preheat the inert gas and avoid cold shock to the annealing chamber 2. In addition, the gas heater 2815 can compensate for heat loss in the gas input channel 2811 and ensure uniform temperature of the inert gas in the gas input channel 2811. The first temperature sensor 2816 is used to monitor the temperature of the inert gas at the gas inlet end of the gas input channel 2811 and feed back to the gas heater 2815.

[0099] With reference to Figure 7 The gas outlet side of each first cavity 291 is provided with a first porous structure 271. The hot inert gas enters the annealing chamber 2 through the first porous structure 271, flows around the lower surface of the coated body 4, and flows to the upper surface of the coated body 4.

[0100] In use, the first heating module 31 is provided with a first through hole 311. The gas outlet end of the gas input channel 2811 passes through the first through hole 311 and is in communication with the gas inlet side of the first cavity 291. Preferably, the gas outlet end of the gas input channel 2811 is in communication with the first porous structure 271 to maintain a constant curtain thickness around the first porous structure 271 and ensure uniform heat convection under the lower surface of the substrate. The first porous structure 271 can be a porous ceramic plate with an average pore size of greater than or equal to 20 μm.

[0101] In actual application, the first pressure difference sensor can be arranged on the gas input channel 2811. The first pressure difference sensor is used to detect the pressure difference between the first side of the first porous structure 271 and the second side thereof, so as to determine whether the pores of the first porous structure 271 are blocked, and to ensure that the hot inert gas uniformly penetrates the first porous structure 271.

[0102] In actual implementation, the heat energy generated by the first heating plate 312 is uniformly distributed through the first rectifying plate 313, and then further uniformly distributed through the first porous structure 271 and into the annealing chamber 2, so as to ensure the uniformity and stability of the heat field.

[0103] The step SS3 of the present application further comprises adjusting the temperature and / or flow rate of the hot inert gas of the gas input assembly 281 based on at least one of the parameters, i.e., the temperature of each region of the coated body 4, the second pressure difference between the inside and outside of the annealing chamber 2, the first pressure difference between the first side and the second side of the first porous structure 271, the flow rate of the gas flow on the upper surface of the coated body 4, and the length of the gas input assembly 281. Among them, the flow rate of the gas flow on the upper surface of the coated body 4 and the temperature of each region of the coated body 4 are preferably considered first, and the second pressure difference between the inside and outside of the annealing chamber 2 is preferably considered second.

[0104] When the temperature and / or flow rate of the hot inert gas of the gas input assembly 281 is adjusted based on at least the temperature of each region of the coated body 4, the step SS3 of the present application comprises steps SS321 to SS323.

[0105] Step SS321: Collect the temperature of each region of the coated body 4, i.e., collect the temperature of each sub-region 421 of the substrate.

[0106] SS322: If the temperature of any region is less than the annealing temperature, the temperature of the hot inert gas in the gas input assembly 281 corresponding to the region is increased.

[0107] In response to the temperature of any sub-region 421 being less than a preset annealing temperature (set according to specific process requirements), the temperature of the hot inert gas in the gas input channel 2811 connected to the first chamber 201 corresponding to the sub-region 421 is increased.

[0108] SS323: If the difference between the temperature of any region and the average temperature of the coated body 4 is greater than or equal to a first threshold value, the temperature of the hot inert gas in the gas input assembly 281 corresponding to the region is adjusted so that the temperature of the region is greater than or equal to the annealing temperature, and the difference between the temperature of the region and the average temperature of the coated body 4 is less than the first threshold value. The first threshold value can be determined based on the properties of the coating material on the coated body 4. The properties of the coating material at least include the annealing temperature and the crystallization sensitivity coefficient of the coating material (the first threshold value is preliminarily determined by the annealing temperature, and further corrected by the crystallization sensitivity coefficient of the coating material).

[0109] In response to the temperature difference between any sub-region 421 and the average temperature of the coated body 4 being greater than or equal to the first threshold value, the temperature of the hot inert gas in the gas input channel 2811 connected to the first chamber 201 corresponding to the sub-region 421 is reduced, so that the temperature difference between the sub-region 421 and the average temperature of the coated body 4 is less than the first threshold value. If the temperature of the sub-region 421 is less than the preset annealing temperature at this time, the temperature of the hot inert gas in the gas input channel 2811 connected to the first chamber 201 corresponding to each sub-region 421 is increased to appropriately increase the average temperature of the coated body 4. In this way, the temperature of each sub-region 421 is greater than or equal to the annealing temperature, and the temperature difference between the sub-region 421 and the average temperature of the coated body 4 is less than the first threshold value.

[0110] When the temperature and / or flow rate of the hot inert gas of the gas input assembly 281 is adjusted based at least on the flow rate of the gas flow on the upper surface of the coated body 4, the step SS3 of the present application includes steps SS331 to SS332.

[0111] Step SS331: The flow rate of the gas flow on the upper surface of the coated body 4 is collected.

[0112] Step SS332: If the flow rate of the gas flow is greater than or equal to the flow rate limit value, the gas flow rate of the gas input assembly 281 is reduced. The flow rate limit value can be determined based on the viscosity threshold of the coated material on the coated body 4, and can also be determined based on the viscosity threshold of the coated material and the density of the hot inert gas (the flow rate limit value is preliminarily determined by the viscosity threshold of the coated material, and is further corrected by the density of the hot inert gas).

[0113] In response to the flow rate of the gas flow on the upper surface of the coated body 4 being greater than or equal to the flow rate limit value, the gas flow rate of the hot inert gas in each gas input channel 2811 is appropriately reduced to avoid disturbance of the coated material by the gas flow, or even blowing the coated material off the substrate.

[0114] When the temperature and / or flow rate of the hot inert gas of the gas input assembly 281 is adjusted based at least on the second pressure difference between the inside and outside of the annealing chamber 2, the step SS3 of the present application includes steps SS341 to SS344.

[0115] Step SS341: The second pressure difference between the inside and outside of the annealing chamber 2 is obtained.

[0116] The second pressure difference = the pressure value inside the annealing chamber 2 - the pressure value outside the annealing chamber 2. It is necessary to maintain the annealing chamber 2 in a micro-positive pressure environment.

[0117] Step SS342: If the second pressure difference is greater than 0, and the second pressure difference is greater than or equal to the second preset threshold value, the gas flow rate of the gas input assembly 281 is reduced.

[0118] The second preset threshold value can be determined based on the porosity of the second porous structure 272, or determined based on the porosity of the second porous structure 272 and the average pore diameter of the pores of the second porous structure 272 (the second preset threshold value is primarily determined based on the porosity of the second porous structure 272, and further corrected based on the average pore diameter of the pores of the second porous structure 272).

[0119] Step SS343: If the second pressure difference is greater than 0 and the pressure difference is less than the second preset threshold value, increase the gas flow rate of the gas input assembly 281.

[0120] Step SS344: If the second pressure difference is less than or equal to 0, trigger a second alarm signal and increase the gas flow rate of the gas input assembly 281.

[0121] When the thermal inert gas temperature and / or flow rate of the gas input assembly 281 is adjusted based on at least the first pressure difference between the first side of the first porous structure 271 and the second side thereof, the step SS3 of the present application comprises steps SS351 to SS352.

[0122] Step SS3451: Obtain the first pressure difference between the first side of the first porous structure 271 and the second side thereof.

[0123] The first pressure difference = the pressure value of the first side of the first porous structure 271 - the pressure value of the second side of the first porous structure 271. Wherein the first side of the first porous structure 271 faces the first chamber 201, and the second side of the first porous structure 271 faces the annealing chamber 2.

[0124] Step SS352: If the first pressure difference is greater than or equal to the first preset threshold value, trigger a first alarm signal and reduce the gas flow rate of the gas input assembly 281.

[0125] The first preset threshold value can be determined based on the porosity of the first porous structure 271, or determined based on the porosity of the first porous structure 271 and the average pore diameter of the pores (the first preset threshold value is primarily determined based on the porosity of the first porous structure 271, and further corrected based on the average pore diameter of the pores of the first porous structure 271).

[0126] Step SS4: Extract the thermal inert gas flowing over the upper surface of the coated body 4 to remove the solvent vapor in the annealing chamber 2 by the gas flow.

[0127] The step SS4 of the present application comprises steps SS411 to SS413.

[0128] Step SS411: Provide one or more second cavities on the top surface 25.

[0129] When multiple second cavities are provided, the multiple second cavities are arranged coaxially along a radial direction, and the axial center positions of the multiple second cavities are aligned with the center of the coating body 4.

[0130] Step SS412: The suction side of each second cavity is provided with a second porous structure 272, and the second porous structure 272 is connected to the annealing chamber 2 to suck the hot inert gas into the second cavity.

[0131] The second porous structure 272 can be a porous aluminum plate, and the porosities of the multiple second cavities are independently adjustable. Preferably, referring to Figure 8 , three second cavities (i.e., a first cavity 2921, a second cavity 2922, and a third cavity 2923) are arranged on the top surface 25, and the porosities of the porous aluminum plates of the three second cavities can be in the following relationship: the porosity of the first cavity 2921 < the porosity of the second cavity 2922 < the porosity of the third cavity 2923. The first cavity 2921 corresponds to the center area 4201 of the effective area 42 of the substrate, the second cavity 2922 corresponds to the transition area 4202 of the effective area 42 of the substrate, the third cavity 2923 corresponds to the edge area 4203 of the effective area 42 of the substrate and the ineffective area 41 of the substrate, and referring to Figure 9 .

[0132] Step SS413: The exhaust side of each second cavity is connected to at least one gas output assembly 282, and the gas output assembly 282 is used to exhaust the hot inert gas from the second cavity.

[0133] In application, the gas output assembly 282 includes a gas output channel. The inlet of the gas output channel is connected to the exhaust side of the second cavity, and the outlet of the gas output channel is connected to a gas recovery system to avoid environmental pollution.

[0134] Further, the gas output channel is provided with a second pressure difference sensor. In addition, the gas output channel is provided with at least one of a second pressure reducing valve, a second flow regulating valve, a second flow meter, and a second temperature sensor. Preferably, along the direction of the flow of the inert gas in the gas output channel, the second pressure reducing valve, the second flow regulating valve, the second flow meter, and the second temperature sensor are arranged on the gas output channel in sequence. The second pressure reducing valve is used to stabilize the exhaust back pressure to avoid the pressure fluctuation of the downstream, such as the gas recovery system, affecting the pressure stability of the annealing chamber 2; the second flow regulating valve is used to dynamically adjust the exhaust flow to match the inlet flow to maintain the micro-positive pressure of 5 Pa to 10 Pa in the chamber to prevent the backflow of external air; the second flow meter is used to monitor the exhaust flow in real time, and the exhaust flow can be used to compare with the data of the inlet flow meter to calculate the gas retention amount; the second temperature sensor is used to monitor the exhaust temperature to prewarn the risk of solvent condensation and prevent the exhaust hole from being blocked; and the second pressure difference sensor is used to monitor the pressure difference between the exhaust port and the annealing chamber 2.

[0135] In actual application, the second heating module 32 is provided with a second through hole 321, and the inlet of the gas output channel passes through the second through hole 321 and is communicated with the exhaust side of the second cavity. Preferably, the inlet of the gas output channel is communicated with the second porous structure 272, so as to uniformly extract the hot inert gas mixed with solvent vapor and avoid disturbing the thermal field and flow field of the annealing chamber 2.

[0136] In actual implementation, the heat energy of the second heating plate 322 is uniformly distributed through the second rectifying plate 323, and then is further uniformly distributed into the annealing chamber 2 through the second porous structure 272, so as to ensure the uniformity and stability of the thermal field.

[0137] The step SS4 of the present application further comprises adjusting the temperature and / or flow of the hot inert gas of the gas output assembly 282 based on at least one of the parameters, i.e., the temperature of each region of the coated body 4, the second pressure difference between the inside and outside of the annealing chamber 2, the flow rate of the gas flow on the upper surface of the coated body 4, and the flow difference between the gas input assembly 281 and the gas output assembly 282. Preferably, the flow rate of the gas flow on the upper surface of the coated body 4 and the temperature of each region of the coated body 4 are considered first, and then the second pressure difference between the inside and outside of the annealing chamber 2 is considered.

[0138] When the temperature and / or flow of the hot inert gas of the gas output assembly 282 is adjusted based on at least the temperature of each region of the coated body 4, the step SS4 of the present application comprises steps SS421 to SS423.

[0139] Step SS421: Collecting the temperature of each region of the coated body 4, i.e., collecting the temperature of each sub-region 421 of the substrate.

[0140] Step SS422: If the temperature of any region is less than the annealing temperature, the gas flow of the gas output assembly 282 corresponding to the region is increased.

[0141] In response to the temperature of any sub-region 421 being less than a preset annealing temperature (set according to specific process requirements), the gas flow of the hot inert gas in the gas output channel communicated with the second cavity 202 corresponding to the sub-region 421 is increased to increase the flow of the gas flow.

[0142] Step SS423: If the difference between the temperature of any region and the average temperature of the coated body 4 is greater than or equal to a first threshold value, the gas flow of the gas output assembly 282 is adjusted so that the temperature of the region is greater than or equal to the annealing temperature, and the difference between the temperature of the region and the average temperature of the coated body 4 is less than the first threshold value.

[0143] The first threshold value is determined based on the characteristics of the coating material on the coated body 4.

[0144] In response to the temperature difference between any sub-region 421 and the average temperature of the coated body 4 being greater than or equal to the first threshold value, the gas flow rate of the thermal inert gas in the gas output channel corresponding to the second chamber 202 connected to the sub-region 421 is reduced to reduce the flow of the gas flow, so that the temperature difference between the sub-region 421 and the average temperature of the coated body 4 is less than the first threshold value. At this time, if the temperature of the sub-region 421 is less than the preset annealing temperature, the gas flow rate of the thermal inert gas in the gas output channel corresponding to the second chamber 202 connected to each sub-region 421 is increased to appropriately increase the average temperature of the coated body 4. In this way, the temperature of each sub-region 421 is greater than or equal to the annealing temperature, and the temperature difference between the sub-region 421 and the average temperature of the coated body 4 is less than the first threshold value.

[0145] When the temperature and / or flow rate of the thermal inert gas of the gas output assembly 282 is adjusted based at least on the gas flow rate on the upper surface of the coated body 4, the step SS4 of the present application comprises steps SS431 to SS432.

[0146] Step SS431: Collect the gas flow rate on the upper surface of the coated body 4.

[0147] Step SS432: If the gas flow rate is greater than or equal to the flow rate limit value, the gas flow rate of the gas output assembly 282 is reduced.

[0148] The flow rate limit value is determined based on the viscosity threshold of the coated material on the coated body 4.

[0149] In response to the gas flow rate on the upper surface of the coated body 4 being greater than or equal to the flow rate limit value, the gas flow rate of the thermal inert gas in each gas output channel is appropriately reduced to avoid disturbance of the coated material by the gas flow, or even blowing the coated material off the substrate.

[0150] When the temperature and / or flow rate of the thermal inert gas of the gas output assembly 282 is adjusted based at least on the second pressure difference between the inside and outside of the annealing chamber 2, the step SS4 of the present application comprises steps SS441 to SS444.

[0151] Step SS441: Obtain the second pressure difference between the inside and outside of the annealing chamber 2.

[0152] The second pressure difference = the pressure value inside the annealing chamber 2 - the pressure value outside the annealing chamber 2. The pressure value outside the annealing chamber 2 can be the pressure value in the air of the second porous structure 272, or the pressure value on the exhaust side of the second chamber.

[0153] Step SS442: If the second pressure difference is greater than 0 and the pressure difference is greater than or equal to the second preset threshold value, the gas flow rate of the gas output assembly 282 is increased. The second preset threshold value is determined based on the porosity of the second porous structure 272.

[0154] Step SS443: If the second pressure difference is greater than 0 and the pressure difference is less than a second preset threshold, then reduce the gas flow rate of the gas output assembly 282.

[0155] Step SS444: If the second pressure difference is less than or equal to 0, then trigger a second alarm signal and reduce the gas flow rate of the gas output assembly 282.

[0156] When the thermal inert gas temperature and / or flow rate of the gas output assembly 282 is adjusted based on at least the second pressure difference between the inside of the annealing chamber 2 and the outside, the step SS4 of the present application comprises steps SS451 to SS452. Step SS451: Obtain the flow difference between the gas input assembly 281 and the gas output assembly 282.

[0157] Obtain the average flow rate of the gas input assembly 281 and the average flow rate of the gas output assembly 282, and calculate the flow difference between the gas input assembly 281 and the gas output assembly 282 according to the average flow rate of the gas input assembly 281 and the average flow rate of the gas output assembly 282. Wherein, the flow difference = the average flow rate of the gas input assembly 281 - the average flow rate of the gas output assembly 282.

[0158] Step SS452: If the flow difference is greater than a first retention threshold, then increase the gas flow rate of the gas output assembly 282 corresponding to the top surface 25 peripheral area.

[0159] In response to the flow difference being greater than the first retention threshold, it indicates that there is more solvent vapor retained in the annealing chamber 2, and the gas flow rate of the thermal inert gas in the gas output channel connected to the third cavity 2923, which is doped with solvent vapor, is increased to carry away the solvent vapor retained in the annealing chamber 2. Wherein, the first retention threshold can be determined based on the volume of the annealing chamber 2, or based on the volume of the annealing chamber 2 and the saturated solvent vapor concentration (the first retention threshold is preliminarily determined based on the volume of the annealing chamber 2, and further corrected based on the saturated solvent vapor concentration).

[0160] On the other hand, the present application introduces an annealing device.

[0161] The annealing device of the present application comprises: an annealing chamber 2, a coated body 4 suspended in the annealing chamber 2, and a controller.

[0162] The bottom surface 26 of the annealing chamber 2 of the present application is provided with one or more first porous structures 271, each of which is connected to at least one gas input assembly 281 for providing hot inert gas. The top surface 25 of the annealing chamber 2 is provided with one or more second porous structures 272, each of which is connected to at least one gas output assembly 282 for discharging hot inert gas. Further, the controller of the present application is used to control the gas input assembly 281 and the gas output assembly 282 to perform the steps of the annealing method of the present application.

[0163] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made with specific examples and comparative examples. It should be understood that the specific examples and comparative examples described herein are only used to explain the present application and do not limit the present application.

[0164] Example 1 / Example 1

[0165] Components of the perovskite precursor solution:

[0166] Mass ratio of solute: formamidinium iodide (FAI): lead iodide (PbI2): cesium bromide (CsBr) = 5.93: 18.07: 1.

[0167] Volume ratio of solvent: N, N-dimethylformamide (DMF): acetonitrile (ACN) = 9: 1.

[0168] The mass fraction of the solute is 43.3%.

[0169] Perovskite precursor solution coating:

[0170] Substrate 23: glass, size 1 m x 0.6 m x 2.2 mm.

[0171] Process: slot coating. Coating head liquid discharge rate: 40 μL / s; coating head moving speed: 50 mm / s.

[0172] Thin film solvent removal: vacuum crystallization (VCD) was performed on the substrate 23 coated with the perovskite precursor solution, and the pressure was 5 Pa.

[0173] Thin film annealing: realized by using the annealing device of the present application. Temperature of inert gas: 130°C; gas flow of inert gas: 80 L / min; annealing time: 20 min.

[0174] Comparative Example 1

[0175] The difference between Comparative Example 1 and Example 1 is in the thin film annealing step. The thin film annealing step of Comparative Example 1 is as follows:

[0176] The existing annealing device is used to realize that the substrate 23 is directly in contact with the carrier. The temperature of the inert gas is 130℃; the gas flow of the inert gas is 80L / min; and the annealing time is 20min.

[0177] The perovskite thin films obtained in Example 1 and Comparative Example 1 are characterized by ultraviolet-visible absorption. It is found that the ultraviolet-visible absorption of the perovskite thin film obtained in Example 1 is stronger than that of Comparative Example 1 at a wavelength of 338nm to 813nm. It is shown that the perovskite thin film obtained in Example 1 has stronger absorption and better crystallinity. Figure 10

[0178] Further, 9 points of the perovskite thin films obtained in Example 1 and Comparative Example 1 are characterized by ultraviolet-visible absorption, and it is found that the values obtained in Figure 11 Figure 11 are calculated to obtain the uniformity of ultraviolet-visible absorption. The uniformity of ultraviolet-visible absorption of Example 1 is 1.83%, and the uniformity of ultraviolet-visible absorption of Comparative Example 1 is 10.88%. It is shown that the perovskite thin film obtained in Example 1 has better uniformity.

[0179] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above embodiments without departing from the principles and spirit of the present application within the scope of the present application. All these changes should be within the protection scope of the present application.​​

Claims

1. An annealing method, characterized by, The method comprises the following steps: a heating module is arranged on the bottom surface (26) and the top surface (25) of the annealing chamber (2) to form a heat field in the annealing chamber (2); the coated body (4) is suspended between the two heating modules; hot inert gas is introduced into the annealing chamber (2) to flow through the upper surface of the coated body (4); the hot inert gas flowing through the upper surface of the coated body (4) is extracted to remove solvent vapor in the annealing chamber (2) by air flow.

2. The annealing method according to claim 1, characterized by, The step of introducing hot inert gas into the annealing chamber (2) comprises: one or more first cavities (291) are arranged on the bottom surface (26); each first cavity (291) is connected to at least one set of gas input components (281) on the gas inlet side, and the gas input components (281) are used to input hot inert gas into the first cavity (291); a first porous structure (271) is arranged on the gas outlet side of each first cavity (291), and the hot inert gas enters the annealing chamber (2) through the first porous structure (271), flows around the lower surface of the coated body (4), and flows to the upper surface of the coated body (4).

3. The annealing method according to claim 2, characterized by, The gas input components (281) used to input hot inert gas into the first cavity (291) comprise: the temperature of each region of the coated body (4) is collected; if the temperature of any region is less than the annealing temperature, the temperature of the hot inert gas in the gas input components (281) corresponding to the region is increased; if the difference between the temperature of any region and the average temperature of the coated body (4) is greater than or equal to a first threshold value, the temperature of the hot inert gas in the gas input components (281) corresponding to the region is adjusted so that the temperature of the region is greater than or equal to the annealing temperature, and the difference between the temperature of the region and the average temperature of the coated body (4) is less than the first threshold value; wherein the first threshold value is determined based on the properties of the coating material on the coated body (4).

4. The annealing method according to claim 2, wherein The gas input components (281) used to input hot inert gas into the first cavity (291) comprise: the flow rate of the air flow on the upper surface of the coated body (4) is collected; if the flow rate of the air flow is greater than or equal to a flow rate limit value, the gas flow rate of the gas input components (281) is reduced; wherein the flow rate limit value is determined based on a viscosity threshold value of the coating material on the coated body (4).

5. The annealing method according to claim 4, wherein The gas input components (281) used to input hot inert gas into the first cavity (291) comprise: a first pressure difference between the first side and the second side of the first porous structure (271) is obtained; if the first pressure difference is greater than or equal to a first preset threshold value, a first alarm signal is triggered, and the gas flow rate of the gas input components (281) is reduced; wherein the first preset threshold value is determined based on the porosity of the first porous structure (271).

6. The annealing method of claim 1, wherein The step of extracting the hot inert gas flowing through the upper surface of the coated body (4) comprises: one or more second cavities are arranged on the top surface (25); a second porous structure (272) is arranged on the gas extraction side of each second cavity, and the second porous structure (272) is connected to the annealing chamber (2) to introduce hot inert gas into the second cavity; Each of the second cavities is connected to at least one gas output assembly (282) on the exhaust side, and the gas output assembly (282) is configured to exhaust the hot inert gas out of the second cavity.

7. The annealing method according to claim 6, characterized in that, The gas output assembly (282) configured to exhaust the hot inert gas out of the second cavity comprises: acquiring a flow rate of the gas flow on the upper surface of the coated body (4); if the flow rate of the gas flow is greater than or equal to a flow rate limit value, reducing the gas flow rate of the gas output assembly (282); wherein the flow rate limit value is determined based on a viscosity threshold of the coating material on the coated body (4).

8. The annealing method according to claim 7, wherein The gas output assembly (282) configured to exhaust the hot inert gas out of the second cavity comprises: acquiring a second pressure difference between the inside and the outside of the annealing chamber 2; if the second pressure difference is greater than 0, and the pressure difference is greater than or equal to a second preset threshold, increasing the gas flow rate of the gas output assembly (282); if the second pressure difference is greater than 0, and the pressure difference is less than the second preset threshold, reducing the gas flow rate of the gas output assembly (282); if the second pressure difference is less than or equal to 0, triggering a second alarm signal and reducing the gas flow rate of the gas output assembly (282); wherein the second preset threshold is determined based on the porosity of the second porous structure (272).

9. The annealing method of claim 7, wherein The gas output assembly (282) configured to exhaust the hot inert gas out of the second cavity comprises: acquiring a flow difference between the gas input assembly (281) and the gas output assembly (282); if the flow difference is greater than a first retention threshold, increasing the gas flow rate of the gas output assembly (282) corresponding to the peripheral area of the top surface (25); wherein the first retention threshold is determined based on the volume of the annealing chamber (2).

10. An annealing apparatus characterized by comprising: Comprises: an annealing chamber (2), the bottom surface (26) of the annealing chamber (2) is provided with one or more first porous structures (271), each of the first porous structures (271) is connected to at least one gas input assembly (281), and the gas input assembly (281) is configured to provide hot inert gas; the top surface (25) of the annealing chamber (2) is provided with one or more second porous structures (272), each of the second porous structures (272) is connected to at least one gas output assembly (282), and the gas output assembly (282) is configured to exhaust the hot inert gas; a coated body (4), the coated body (4) is suspended in the annealing chamber (2); a controller, the controller is configured to control the gas input assembly (281) and the gas output assembly (282) to perform the steps of the annealing method according to any one of claims 1 to 9.

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