Fullerene film, preparation method thereof and solar cell

Abstract

The invention relates to the technical field of film preparation, in particular to a fullerene film, a preparation method thereof and a solar cell, and the preparation method comprises the following steps: providing a substrate; mixing a fullerene material with a dielectric material to prepare a mixture; carrying out vacuum evaporation on the mixture, and forming a fullerene film on the substrate; wherein the melting point of the dielectric material is 2623 DEG C or above, and the heat conduction coefficient is 138 W / m.K or above. The dielectric material is mixed into the fullerene material as a heat conduction medium, so that the fullerene material is uniformly heated, the rate mutation caused by local overheating of the fullerene material is inhibited, and the evaporation rate fluctuation range is reduced; meanwhile, the buffering effect on temperature jump in the initial heating stage of vacuum evaporation is achieved through the high heat capacity characteristic of the dielectric material, the evaporation rate curve is smooth, and the overshoot phenomenon is eliminated; and the dielectric material is mixed into the fullerene material, so that the evaporation activation energy of the material is reduced, and the evaporation response speed is increased.

Description

Technical Field

[0001] This application relates to the field of thin film preparation technology, and in particular to fullerene thin films and their preparation methods, and solar cells. Background Technology

[0002] Fullerene materials have important applications in semiconductor devices, photovoltaic cells, and superconducting materials due to their unique electronic structure and optical properties. Traditional processes for preparing fullerene thin films typically use pure fullerene material as the evaporation source. However, due to the uneven heating of fullerene powder and its large response coefficient, evaporation rate fluctuations are prone to occur at high temperatures, resulting in poor uniformity of the prepared fullerene film. Furthermore, excessive evaporation of the evaporation source material during film preparation leads to low material utilization. The rapid increase in evaporation rate during the initial heating phase (overshoot) places high demands on the control system and increases costs. Finally, the evaporation response is slow and difficult to adjust. Summary of the Invention

[0003] Based on this, this application provides fullerene thin films and their preparation methods, as well as solar cells. In the process of preparing fullerene thin films using this preparation method, the fullerene material is heated uniformly, the evaporation rate fluctuates little at high temperatures, the material utilization rate is high, there is no overshoot phenomenon, the evaporation response is rapid, and the cost is low.

[0004] The first aspect of this application provides a method for preparing a fullerene thin film, comprising the following steps: providing a substrate; mixing a fullerene material with a dielectric material to prepare a mixture; vacuum evaporating the mixture to form a fullerene thin film on the substrate; wherein the dielectric material has a melting point of 2623°C or higher and a thermal conductivity of 138 W / m·K or higher.

[0005] In some embodiments, the step of preparing a mixture by mixing fullerene material and dielectric material includes: adding fullerene material and dielectric material to a crucible under the protection of a protective gas to prepare a mixture, wherein the mixture is in a homogeneous or non-homogeneous mixing state.

[0006] In some embodiments, the step of preparing a mixture by mixing fullerene material with a dielectric material includes: stirring and / or oscillating the fullerene material and the dielectric material for 30 min to 120 min under a protective gas atmosphere to prepare the mixture.

[0007] This application controls the stirring and / or oscillation time to 30 min to 120 min to ensure uniform mixing between the fullerene material and the medium material while ensuring production efficiency, and sufficient dispersion of the fullerene material in the mixture.

[0008] In some embodiments, the dielectric material includes one or more of tungsten metal, molybdenum metal, and graphite.

[0009] In some embodiments, the mass ratio of fullerene material to dielectric material is 1:(0.5~5).

[0010] In some embodiments, the particle size D50 of the fullerene material is less than 100 nm.

[0011] In some embodiments, the particle size D50 of the dielectric material is 1 μm to 10 μm.

[0012] In some embodiments, the particle size D50 of the dielectric material is 2μm to 5μm.

[0013] In some embodiments, the step of vacuum evaporation of the mixture to form a fullerene film on a substrate includes: placing the substrate and the mixture in a chamber, evacuating to a preset vacuum level, and depositing at a preset deposition rate to form a fullerene film on the substrate.

[0014] In some implementations, the preset vacuum level is 1×10⁻⁶. -4 Pa ~ 1×10 -3 Pa.

[0015] In some implementations, the preset deposition rate is 0.1 Å / S to 10 Å / S.

[0016] In some implementations, the step of ultrasonic cleaning of the substrate is also included.

[0017] The second aspect of this application provides a fullerene film prepared using the method for preparing fullerene films as provided in the first aspect of this application.

[0018] A third aspect of this application provides a solar cell comprising a fullerene thin film prepared using the method for preparing a fullerene thin film as provided in the first aspect of this application, or comprising a fullerene thin film as provided in the second aspect of this application.

[0019] Compared with the prior art, this application has the following beneficial effects: By mixing a dielectric material into the fullerene material, the dielectric material, as a heat conduction medium, promotes the uniform distribution of heat, making the fullerene material heated evenly, suppressing the sudden change in evaporation rate caused by local overheating of the fullerene material, and reducing the fluctuation range of the evaporation rate; at the same time, the high heat capacity of the dielectric material is used to buffer the temperature jump in the initial heating stage of vacuum evaporation, making the evaporation rate curve smooth and eliminating overshoot; and the mixing of the dielectric material into the fullerene material reduces the evaporation activation energy of the fullerene material and improves the evaporation response speed. Attached Figure Description

[0020] To better describe and illustrate embodiments or examples of the applications disclosed herein, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the embodiments or examples currently described, or the best mode of conduct of these applications as currently understood. Furthermore, throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0021] Figure 1 This is a process flow diagram of a method for preparing fullerene thin films according to one embodiment of this application.

[0022] Figure 2 This is the evaporation rate-time curve in Example 1 of this application.

[0023] Figure 3 This is the evaporation rate-time curve in Example 2 of this application.

[0024] Figure 4 This is the evaporation rate-time curve in Example 3 of this application.

[0025] Figure 5 This is the evaporation rate-time curve in Example 4 of this application.

[0026] Figure 6 This is the evaporation rate-time curve in Example 5 of this application.

[0027] Figure 7 This is the evaporation rate-time curve in Example 6 of this application.

[0028] Figure 8 This is the evaporation rate-time curve in Example 7 of this application.

[0029] Figure 9 This is the evaporation rate-time curve in Example 8 of this application.

[0030] Figure 10 This is the evaporation rate-time curve in Example 9 of this application.

[0031] Figure 11 This is the evaporation rate-time curve in Example 10 of this application.

[0032] Figure 12 This is the evaporation rate-time curve in Example 11 of this application.

[0033] Figure 13 This is the evaporation rate-time curve from Comparative Example 1 of this application.

[0034] Figure 14 This is a SEM image of the fullerene film in Example 1 of this application.

[0035] Figure 15 This is a SEM image of the fullerene film in Example 2 of this application.

[0036] Figure 16 This is a SEM image of the fullerene film in Example 3 of this application.

[0037] Figure 17 This is a SEM image of the fullerene film in Example 4 of this application.

[0038] Figure 18 This is a SEM image of the fullerene film in Example 5 of this application.

[0039] Figure 19 This is a SEM image of the fullerene film in Example 6 of this application.

[0040] Figure 20 This is a SEM image of the fullerene film in Example 7 of this application.

[0041] Figure 21 This is a SEM image of the fullerene film in Example 8 of this application.

[0042] Figure 22 This is a SEM image of the fullerene film in Example 9 of this application.

[0043] Figure 23 This is a SEM image of the fullerene film in Example 10 of this application.

[0044] Figure 24 This is a SEM image of the fullerene film in Example 11 of this application.

[0045] Figure 25 This is a SEM image of the fullerene film in Comparative Example 1 of this application. Detailed Implementation

[0046] The following detailed description, with appropriate reference to the accompanying drawings, discloses some embodiments of the perovskite thin film and its preparation method, perovskite solar cells, and tandem solar cells of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0047] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this document; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, stating that a parameter is an integer selected from "2-10" is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0048] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0049] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0050] Unless otherwise specified, the terms "comprising," "containing," and "including" as used in this application can be open-ended or closed-ended. In open-ended cases, for example, "comprising," "containing," and "including" can mean that other members, elements, or method steps not listed can also be included, or that only the listed members, elements, or method steps can be included.

[0051] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0052] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0053] In this application, if the unit of a data range is only followed by the right endpoint, it means that the units of the left and right endpoints are the same. For example, "30~120min" means "30min~120min".

[0054] like Figure 1 As shown, the first aspect of this application provides a method for preparing a fullerene film, comprising the following steps: S1, providing a substrate.

[0055] S2. Mix the fullerene material with the dielectric material to prepare a mixture.

[0056] S3, vacuum evaporation of the mixture to form a fullerene film on the substrate.

[0057] The dielectric material has a melting point of 2623℃ or higher and a thermal conductivity of 138W / m·K or higher.

[0058] This application mixes fullerene materials with a dielectric material. Regardless of the uniformity of the mixture, the dielectric material, acting as a heat transfer medium, promotes uniform heat distribution, resulting in a uniform saturated vapor pressure escaping from the crucible. This, in turn, ensures uniform heating of the fullerene material, suppressing abrupt rate changes caused by localized overheating and reducing the fluctuation range of the evaporation rate. The high heat capacity of the dielectric material buffers the temperature surge during the initial heating stage of vacuum evaporation, smoothing the evaporation rate curve and eliminating overshoot. Simultaneously, incorporating the dielectric material into the fullerene material lowers the evaporation activation energy, improving the evaporation response speed and enhancing power stability.

[0059] It should be noted that the "mixing" in step S2 of this application refers to the simultaneous presence of fullerene material and dielectric material in the crucible of the vacuum evaporation equipment. For example, the fullerene material and dielectric material are poured into the crucible alternately in sequence, arranged in layers, to prepare a mixture; another example is that the fullerene material and dielectric material are stirred and / or vibrated to mix and then poured into the crucible to prepare a mixture; yet another example is that the fullerene material is placed in one side of the crucible and the dielectric material is placed in the other side of the crucible to prepare a mixture.

[0060] In some implementations, the substrate can be one or more of silicon wafers, glass, and metal foil.

[0061] In some implementations, the glass is a transparent conductive glass.

[0062] It is understood that "transparent conductive glass" refers to a composite functional material formed by depositing a layer of transparent conductive oxide (TCO) film on the surface of a glass substrate. Transparent conductive glass includes, but is not limited to, one or more of indium tin oxide (ITO) transparent conductive glass, fluorine-doped tin oxide (FTO) transparent conductive glass, aluminum-doped zinc oxide (AZO) transparent conductive glass, and PET transparent conductive glass.

[0063] In some embodiments, the fullerene material includes, but is not limited to, one or more of C20, C60, C70, C76, methyl [6,6]-phenyl-C61-butyrate (PCBM), and indene-C60 diadduct (ICBA).

[0064] In some embodiments, the step of preparing a mixture by mixing fullerene material with a dielectric material includes: stirring and / or oscillating the fullerene material and the dielectric material for 30 min to 120 min under a protective gas atmosphere to prepare the mixture.

[0065] It is understood that the stirring and / or oscillation time includes, but is not limited to, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, and 120 min.

[0066] In some implementations, the protective gas can be an inert gas, such as argon.

[0067] In other embodiments, the protective gas may also be a non-inert gas, such as nitrogen.

[0068] Furthermore, researchers also found that because fullerene powder is prone to agglomeration and clumping, which can affect the uniformity of heating of the material, the preferred method for mixing fullerene powder with the dielectric material is to stir and / or vibrate the fullerene powder and the dielectric material and then pour them into a crucible.

[0069] In one specific embodiment, under the protection of argon gas, the fullerene material and the medium material are stirred in a three-dimensional mixer for 30 min to 120 min to ensure that the medium material is evenly dispersed among the fullerene material, further preventing the fullerene material from agglomerating and clumping, and making the fullerene material heat more evenly.

[0070] In one specific embodiment, under the protection of nitrogen, the fullerene material and the medium material are shaken in a shaker at a speed of 700 rpm to 900 rpm for 30 min to 120 min, so as to make the medium material uniformly dispersed between the fullerene material, further preventing the fullerene material from agglomerating and clumping, and making the fullerene material more uniformly heated.

[0071] This application controls the stirring and / or oscillation time to 30 min to 120 min to ensure uniform mixing between the fullerene material and the medium material while maintaining production efficiency, and to ensure sufficient dispersion of the fullerene material in the mixture.

[0072] In some embodiments, the dielectric material includes one or more of tungsten metal, molybdenum metal, and graphite.

[0073] It is understood that this application does not specifically limit the type of graphite; it can be either artificial or natural graphite. Without departing from the overall inventive concept of this application, any known graphite that meets the melting point and thermal conductivity requirements of the medium material can be used in this application. For example, the graphite is flake graphite or block graphite.

[0074] In some embodiments, the mass ratio of fullerene material to dielectric material is 1:(0.5~5), including but not limited to 1:0.5, 1:1, 1:2, 1:3, 1:4, and 1:5. Further, the mass ratio of fullerene material to dielectric material is 1:(2~5). Even further, the mass ratio of fullerene material to dielectric material is 1:(2~4).

[0075] If the proportion of fullerene material is too high, the likelihood of agglomeration and clumping is also higher, increasing the risk of large fluctuations in evaporation rate due to agglomeration. Furthermore, the initial evaporation temperature and power will increase, and the evaporation rate response time will also increase. Conversely, if the proportion of fullerene material is low, the absolute evaporation amount is smaller, making it more sensitive to temperature and power fluctuations and prone to evaporation rate fluctuations. Therefore, this application controls the mass ratio of fullerene material to medium material at 1:(0.5~5). On the one hand, this reduces the probability of agglomeration of the evaporation source material caused by an excessively high proportion of fullerene material, thereby reducing the risk of large fluctuations in evaporation rate due to agglomeration. On the other hand, it reduces the risk of evaporation rate fluctuations caused by an excessively low proportion of fullerene material.

[0076] In some embodiments, the particle size D50 of the fullerene material is less than 100 nm. Further, the particle size D50 of the fullerene material is 20 nm to 100 nm.

[0077] In some embodiments, the particle size D50 of the dielectric material is 1 μm to 10 μm, including but not limited to 1 μm, 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, and 10 μm. Further, the particle size D50 of the dielectric material is 2 μm to 5 μm.

[0078] In some embodiments, the step of forming a fullerene film on a substrate using the above-mentioned S3 vacuum evaporation mixture includes: placing the substrate and the mixture in a chamber, evacuating to a preset vacuum level, heating the mixture, and depositing at a preset deposition rate to form a fullerene film on the substrate.

[0079] In some embodiments, the step of forming a fullerene film on the substrate by vacuum evaporation of the above-mentioned S3 mixture includes: S31, fixing the substrate on the substrate stage, placing the mixture in the evaporation boat, and evacuating to a preset vacuum level.

[0080] S32. Cover the base with a baffle and heat the mixture.

[0081] S33. When the deposition rate of the fullerene material is within the preset deposition rate range, remove the baffle and deposit a fullerene film on the substrate.

[0082] In some embodiments, the preset vacuum level in S31 is 1×10⁻⁶. -4 Pa ~ 1×10 -3 Pa.

[0083] In some embodiments, the preset deposition rate in S32 is 0.1 Å / S to 10 Å / S.

[0084] In some implementations, the step of ultrasonic cleaning of the substrate is also included.

[0085] In some implementations, ethanol and deionized water are used as ultrasonic cleaning media to clean the substrate a preset number of times.

[0086] In some embodiments, the step of ultrasonically cleaning the substrate is followed by the step of drying the substrate using a vacuum drying oven.

[0087] In some embodiments, the step S3 above is further included: S4, after the fullerene film deposition is completed, the substrate is covered with a baffle and the mixture is cooled to room temperature.

[0088] S5. Introduce nitrogen into the vacuum evaporation chamber. Once the pressure inside the chamber reaches the external atmospheric pressure, remove the substrate.

[0089] In some embodiments, the heating method for the mixture during vacuum evaporation includes, but is not limited to, one or more of electron beam heating, resistance heating, high-frequency induction heating, electric arc heating, and laser heating. Further, the heating method for the mixture is electron beam heating or resistance heating.

[0090] In some implementations, an evaporation rate signal from the evaporation source is acquired by an evaporation rate sensor (e.g., a quartz crystal oscillator sensor) and sent to an automatic control system. The automatic control system maintains the evaporation rate within a set range by dynamically adjusting process parameters (e.g., heating power, electron beam current).

[0091] The fullerene films prepared in this application are more uniform and dense, with lower overall roughness.

[0092] The fullerene thin film prepared in this application has a more uniform refractive index and conforms to the theoretical limit of the refractive index of the fullerene material itself, which is 1.8-2.2.

[0093] The fullerene film prepared in this application can achieve a thickness of 1 nm. Compared with traditional methods that have poor batch repeatability in preparing fullerene films, the preparation method provided in this application is stable with a repeatability of over 98%, and the quality of the prepared fullerene film is also good.

[0094] The preparation method provided in this application has a short overall process time and high production efficiency.

[0095] The preparation method provided in this application does not require a specific initial evaporation temperature for the crucible. However, during the vapor deposition process of normal fullerene materials, different initial evaporation temperatures can lead to process fluctuations. (Initial evaporation temperature refers to the temperature at which evaporation begins when the crucible temperature is 20°C, 40°C, or other temperatures). Adding a dielectric material reduces the process's requirement for the crucible's initial evaporation temperature.

[0096] The second aspect of this application provides a fullerene film prepared using the method for preparing fullerene films as provided in the first aspect of this application.

[0097] A third aspect of this application provides a solar cell comprising a fullerene thin film prepared using the method for preparing a fullerene thin film as provided in the first aspect of this application, or comprising a fullerene thin film as provided in the second aspect of this application.

[0098] In some embodiments, the solar cell in this application is a perovskite cell, which has an upright structure and, from bottom to top, comprises a transparent conductive glass, an electron transport layer, a perovskite absorber layer, a hole transport layer, and a metal electrode. The fullerene thin film provided in this application serves as the electron transport layer in the perovskite cell.

[0099] In some embodiments, the solar cell in this application is a perovskite cell with an inverted structure, wherein a transparent conductive glass, a hole transport layer, a perovskite absorber layer, an electron transport layer, and a metal electrode are disposed sequentially from bottom to top. The fullerene thin film provided in this application serves as the electron transport layer in the perovskite cell.

[0100] The present application will be further described below with reference to specific embodiments and comparative examples.

[0101] Example 1: This example provides a method for preparing a fullerene film.

[0102] S1. Provide a quartz glass substrate.

[0103] S2. Weigh C60 and tungsten powder (melting point 3422℃, thermal conductivity 173W / m·K) at a mass ratio of 1:2. Under argon protection, stir C60 and tungsten powder in a three-dimensional mixer for 80 minutes to prepare a mixture. The particle size of C60 is 100nm, and the particle size of tungsten powder is 5μm.

[0104] S3. Fix the substrate on the substrate stage, place the mixture in the evaporation boat, and evacuate to a vacuum level of 5×10⁻⁶. - 4 Pa, the substrate is covered with a baffle, the mixture is heated by resistance heating, the deposition rate is 1 Å / S, the baffle is removed, and a fullerene film is deposited on the quartz glass substrate.

[0105] S4. After the fullerene film deposition is completed, cover the substrate with a baffle and cool the mixture to room temperature.

[0106] S5. Introduce nitrogen into the vacuum evaporation chamber. Once the pressure inside the chamber reaches the external atmospheric pressure, remove the substrate.

[0107] Example 2: This example adopts the same technical solution as Example 1, except that the medium material in Example 2 is molybdenum powder (melting point of 2623℃, thermal conductivity of 138W / m·K).

[0108] Specifically, the steps include: S1, providing a quartz glass substrate.

[0109] S2. Weigh C60 and molybdenum powder at a mass ratio of 1:3. Under argon protection, stir C60 and molybdenum powder in a three-dimensional mixer for 80 minutes to prepare a mixture. The particle size of C60 is 100 nm, and the particle size of molybdenum powder is 5 μm.

[0110] S3. Fix the quartz glass substrate on the substrate stage, place the mixture in the evaporation boat, and evacuate to a vacuum degree of 5×10⁻⁶. -4Pa, the quartz glass substrate is covered with a baffle, the mixture is heated by resistance heating, the deposition rate is 1 Å / S, the baffle is removed, and a fullerene film is deposited on the quartz glass substrate.

[0111] S4. After the fullerene film deposition is completed, the quartz glass substrate is covered with a baffle, and the mixture is cooled to room temperature.

[0112] S5. Introduce nitrogen into the vacuum evaporation chamber. Once the pressure inside the chamber reaches the external atmospheric pressure, remove the substrate.

[0113] Example 3: This example adopts the same technical solution as Example 1. The difference between Example 3 and Example 1 is that C60 and tungsten powder are weighed in a mass ratio of 1:0.5.

[0114] Example 4: This example adopts the same technical solution as Example 1, except that in Example 4, C60 and tungsten powder are weighed at a mass ratio of 1:4.

[0115] Example 5: This example adopts the same technical solution as Example 1, except that in Example 5, C60 and tungsten powder are weighed at a mass ratio of 1:5.

[0116] Example 6: This example uses the same technical solution as Example 1, except that the particle size of the tungsten powder in Example 6 is 1 μm.

[0117] Example 7: This example uses the same technical solution as Example 1, except that the particle size of the tungsten powder in Example 7 is 2μm.

[0118] Example 8: This example uses the same technical solution as Example 1, except that the particle size of the tungsten powder in this example is 10 μm.

[0119] Example 9: This example adopts the same technical solution as Example 1, except that in this example, C60 and tungsten powder are weighed at a mass ratio of 1:6.

[0120] Example 10: This example adopts the same technical solution as Example 1, except that in this example, C60 and tungsten powder are weighed at a mass ratio of 1:10.

[0121] Example 11: This example adopts the same technical solution as Example 1, except that the medium material in this example is particulate graphite (melting point is about 3600℃, thermal conductivity is 2000W / m·K).

[0122] Comparative Example 1: This comparative example provides a method for preparing a fullerene thin film.

[0123] S1. Provide a quartz glass substrate.

[0124] S2. Provide C60 of the same mass as in Example 1, wherein the particle size of C60 is 100 nm.

[0125] S3. Fix the quartz glass substrate on the substrate stage, place C60 in the evaporation boat, and evacuate to a vacuum level of 5 × 10⁻⁶. -4 Pa, the quartz glass substrate is covered with a baffle, and the mixture is heated to a deposition rate of 1 Å / s using resistance heating. The baffle is then removed, and a fullerene film is deposited on the quartz glass substrate.

[0126] S4. After the fullerene film deposition is completed, the quartz glass substrate is covered with a baffle to cool C60 to room temperature.

[0127] S5. Introduce nitrogen into the vacuum evaporation chamber. Once the pressure inside the chamber reaches the external atmospheric pressure, remove the substrate.

[0128] Test examples: The above embodiments and comparative examples were tested as follows.

[0129] (1) Initial evaporation temperature: The temperature at which the evaporation source is heated and the evaporation rate of C60 begins to be detectable is recorded as T0, in °C. The results are shown in Table 1 below.

[0130] (2) Evaporation rate fluctuation range (including rate stability and whether there are spikes in the curve), the results are shown in Table 1 below.

[0131] (3) Power-evaporation rate response time (the time from power increase to change in evaporation rate), the results are shown in Table 1 below.

[0132] (4) Power (power during the period from when the evaporation rate begins to change until the end of the entire evaporation process).

[0133] (5) Evaporation rate-time curve, with time as the horizontal axis and evaporation rate as the vertical axis.

[0134] The results are as follows Figure 2-13 As shown, where, Figures 2-12 The evaporation rate-time curves correspond to Examples 1-11, respectively. Figure 13 Evaporation rate-time curve for example 1.

[0135] (6) Average refractive index: Prepare 10 batches, 30 pieces per batch, and calculate the average refractive index (visible light region).

[0136] (7) Average roughness: Prepare 10 batches, 30 pieces per batch, and calculate the average roughness (nm).

[0137] (8) Batch repeatability: Prepare 100 pieces, calculate the average refractive index / average roughness, and calculate the batch repeatability.

[0138] (9) The fullerene films prepared in the above examples and comparative examples were processed by scanning electron microscopy (SEM images), and the results are as follows: Figure 14-25 As shown. Among them, Figures 14-24 SEM images of the fullerene films from Examples 1-11, respectively. Figure 25 SEM image of the fullerene film corresponding to ratio 1.

[0139] Table 1

[0140] Initial evaporation temperature (°C) Evaporation rate fluctuation range (%) Power-evaporation rate response time (s) Power (W) Mean refractive index Average roughness (nm) Batch repeatability (%) Example 1 200 1 5 160 2.15 1.17 98% Example 2 210 1.5 13 160~164 2.03 1.28 93% Example 3 240 3 70 160~200 1.94 1.87 87% Example 4 230 2 20 160~170 1.98 1.34 90% Example 5 210 10 23 160~180 1.91 2.13 85% Example 6 200 30 13 160~164 1.89 2.57 78% Example 7 203 55 13 160-162 1.85 3.18 75% Example 8 205 70 15 160~166 1.81 3.4 70% Example 9 320 5 25 200~260 1.83 3.23 73% Example 10 340 8 30 260~300 1.81 3.4 71% Example 11 205 1.5 8 162 2.07 1.23 95% Comparative Example 1 280 25 90 180~200 1.8 3.98 60%

[0141] As shown in Table 1, the preparation method provided in this application can reduce the initial evaporation temperature (the temperature at which a detectable evaporation rate appears). The possible reasons are: the fullerene material is tightly wrapped by the medium material, so the heating is more uniform, avoiding local evaporation caused by local overheating due to the design of the evaporation equipment itself; thus avoiding false evaporation rate obtained by the crystal oscillator due to local evaporation, premature entry into PID regulation, resulting in a large error in the entire evaporation process, reducing the evaporation rate fluctuation range from ±25% in Comparative Example 1 to ±1%; shortening the power-evaporation rate response time, achieving a response within 5 seconds; and reducing the required power.

[0142] according to Figure 2-12 It is evident that the preparation method provided in this application requires a shorter heating time, has a faster response, a more stable evaporation rate, a smoother rate curve, and exhibits no significant temperature jump or overshoot in the initial heating stage.

[0143] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a fullerene thin film, characterized in that, Includes the following steps: Provide a base; Fullerene materials are mixed with dielectric materials to prepare a mixture; The mixture is vacuum-deposited to form the fullerene film on the substrate; The medium material has a melting point of 2623℃ or higher and a thermal conductivity of 138W / m·K or higher.

2. The method for preparing fullerene thin films according to claim 1, characterized in that, The step of preparing a mixture by mixing the fullerene material with the medium material includes: adding the fullerene material and the medium material into a crucible under the protection of a protective gas to prepare a mixture, wherein the mixture is in a homogeneous or non-homogeneous mixing state.

3. The method for preparing fullerene thin films according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The medium material includes one or more of tungsten metal, molybdenum metal, and graphite; (2) The mass ratio of the fullerene material to the medium material is 1:(0.5~5).

4. The method for preparing fullerene thin films according to claim 1, characterized in that, The particle size D50 of the fullerene material is below 100 nm.

5. The method for preparing fullerene thin films according to claim 1, characterized in that, The particle size D50 of the medium material is 1μm to 10μm.

6. The method for preparing fullerene thin films according to claim 1, characterized in that, The step of vacuum evaporating the mixture to form the fullerene film on the substrate includes: placing the substrate and the mixture in a chamber, evacuating to a preset vacuum level, and depositing at a preset deposition rate to form the fullerene film on the substrate.

7. The method for preparing fullerene thin films according to claim 6, characterized in that, The preset vacuum level is 1×10⁻⁶. -4 Pa ~ 1×10 -3 Pa; and / or the preset deposition rate is 0.1 Å / S to 10 Å / S.

8. The method for preparing fullerene thin films according to claim 1, characterized in that, It also includes the following steps: The substrate is ultrasonically cleaned.

9. A fullerene thin film, characterized in that, The fullerene film was prepared using the method described in any one of claims 1 to 8.

10. A solar cell, characterized in that, This includes fullerene films prepared by the method described in any one of claims 1 to 8, or fullerene films as described in claim 9.

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