A method for preparing carbon nanorings

Abstract

The preparation method of the carbon nanoring is prepared by using glucose, ferrocene, deionized water and hydrogen as raw materials, respectively preparing glucose ferrocene solution, hydrogenation reaction, washing and drying, ball milling, washing and purifying and drying steps; wherein the mass ratio of glucose, ferrocene and deionized water is 50:1:500. The product prepared by the application overcomes the problem that the current carbon nanotube increases the contact resistance of the device due to agglomeration, thereby reducing the photoelectric efficiency of the device. The product is used as an electron transport layer of an inverted perovskite solar cell, which significantly improves the photoelectric performance of the device. The carbon nanoring modified device has obvious improvement in photovoltaic performance, the open circuit voltage is 1.04V, the EQE of the carbon nanoring modified device is obviously increased in the range of 550-750nm, and the integral current of the device reaches 22.02mA / cm 2 , which is obviously higher than 19.09mA / cm 2 of the comparative device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon nanomaterials, and particularly relates to a preparation method of carbon nanorings (CNRs). BACKGROUND

[0002] Perovskite is named after Russian mineralogist Lev Perovski, and is a material with the same crystal structure as the mineral calcium titanate oxide (the earliest discovered perovskite crystal CaTiO3). Perovskite solar cells (PSC) are solar cells that use perovskite-type organic metal halide semiconductors as light-absorbing materials. Perovskite originally referred only to the mineral calcium titanate (CaTiO3), and later the structure of ABX3 and similar crystals were collectively referred to as perovskite materials. Perovskite cells belong to the third generation of solar cells, and their structure can be roughly divided into two categories: positive (n-i-p) structure and inverted (p-i-n) structure, and the cell structure is simple. Taking an inverted planar perovskite cell as an example, from bottom to top, there are: glass, transparent electrode (ITO or FTO), electron transport layer, perovskite layer, hole transport layer, and metal electrode.

[0003] Inverted structure perovskite solar cells can be prepared by solution method at a relatively low temperature, thereby having a relatively low preparation cost and a relatively simple preparation process, and showing strong application value in the field of flexible display. For perovskite solar cells, finding a charge blocking layer / transport layer with a long transport distance and a perovskite absorption layer is the key to realizing its commercial application, and various organic / inorganic electron transport layers (including TiO2, ZnO and fullerene derivatives) and hole transport layers (including Spiro-OMeTAD, PEDOT:PSS and NiOx) have been developed for application in perovskite solar cells. In the structure of perovskite solar cells, especially in the PCBM (fullerene derivative) electron transport layer, electrons generally diffuse to the electrode through a curved transmission path, which can cause the electrons to recombine in the PCBM (fullerene derivative) film or at the interface of the buffer layer, thereby reducing the performance of the photovoltaic device. Changing the curved transmission of electrons to a straight transmission path can effectively avoid the recombination of electrons with various defects during transmission, and can also effectively accelerate the carrier transport. Carbon nanomaterials are widely used in the hole transport layer of perovskite solar cells based on their excellent photoelectric properties. For example, it is reported in the literature that the use of carbon nanotubes as an additive can greatly improve the carrier transport properties of photovoltaic devices; and the use of carbon nanotubes to make a top electrode of a perovskite solar cell can greatly improve the stability of the device. Therefore, carbon nanostructures such as nanotubes and nanorods are considered to be a good choice for improving electron transport.

[0004] Although carbon nanotubes have very broad application prospects in the field of optoelectronics, carbon nanotubes are prone to agglomeration and entanglement, and such agglomeration increases the contact resistance of the device, thereby affecting the conductivity of the device and reducing the photoelectric efficiency of the device. In addition, during the preparation of the device, the agglomeration and entanglement between the carbon nanotubes will introduce more defects in the transmission layer of the device, causing unnecessary recombination between carriers, thereby greatly reducing the photoelectric efficiency of the photovoltaic device. Therefore, finding a low-cost hole transport layer substitute has far-reaching significance for the development of inverted perovskite solar cells. SUMMARY

[0005] The present application aims to provide a preparation method of carbon nanorings.

[0006] The present application is realized by the following technical solutions:

[0007] A preparation method of a carbon nanoring, characterized in that it is prepared by taking glucose, ferrocene, deionized water and hydrogen as raw materials, respectively preparing a glucose ferrocene solution, carrying out a hydrogenation reaction, washing and drying, ball milling, washing and purifying, and drying steps; wherein the mass ratio of the glucose, ferrocene and deionized water is 50:1:500.

[0008] Further, the preparation of the glucose ferrocene solution is to take glucose and ferrocene, respectively, add deionized water to a suitable container, stir for 10-20 minutes, and dissolve to obtain the glucose ferrocene solution, and the stirring speed is 50-70 r / min.

[0009] Further, the hydrogenation reaction is to first add a tubular furnace to 950-1050℃, continuously inject H2 and Ar under the condition of heat preservation, inject the glucose ferrocene solution into the tubular furnace with a syringe, continuously inject H2 and Ar for 10-15 minutes, close H2, continue to inject Ar, stop heat preservation of the tubular furnace and naturally cool to room temperature, and collect the product; wherein the gas flow ratio of H2 and Ar is 1:17, and the volume mass ratio of H2 inflow volume per minute to glucose is 10:1.

[0010] Further, the washing and drying is to take the product after the hydrogenation reaction, add 0.5 mol / L hydrochloric acid for cleaning, then add ethanol for cleaning, and finally add deionized water for cleaning, place in a reduced pressure drying box after cleaning, set the vacuum degree to -0.05 MPa to -0.08 MPa and the temperature to 70-80℃, dry for 8-12 hours to obtain the dried product, and reserve for use; the mass ratio of the hydrogenation reaction product, hydrochloric acid, ethanol and deionized water is 1:15-20:40-60:80-120.

[0011] Further, the ball milling is that the dried product is placed in a ball mill, iron powder is added, and the ball milling is carried out for 100-120 minutes under a sealed condition to obtain a ball-milled product; wherein the mass ratio of the dried product to the iron powder is 1:20, and the particle size of the iron powder is 200-400 μm.

[0012] Further, the washing and purification is that the ball-milled product is placed in a suitable container, 0.5 mol / L hydrochloric acid is added, and the soaking is carried out for 20-30 minutes, then the product is taken out, placed in deionized water, soaked for 5-10 minutes, placed in a centrifuge, and the precipitate is taken out, then the precipitate is placed in deionized water again, soaked for 5-10 minutes, placed in a centrifuge again, and the centrifugal precipitate is taken out to obtain a centrifugal product; wherein the mass-volume ratio of the ball-milled product to the hydrochloric acid is 1:15-20, the mass-volume ratio of the ball-milled product to the deionized water is 1:20, and the centrifugal speed is 6000-8000 r / min, and the centrifugal time is 10-15 minutes.

[0013] Further, the drying is that the centrifugal product obtained in the above method is placed in a blast drying oven, the temperature is set to 80-90 ℃, and the drying is carried out for 10-12 hours, and the carbon nanorings are obtained.

[0014] The specific mass ratio of the above specific glucose to ferrocene provides a suitable carbon-oxygen ratio for the present application, and finally makes the carbon nanorings of the present application have a suitable length. Glucose, as the main reactant, provides a carbon source and an oxygen source for the present application. Ferrocene, as a catalyst for the reaction of the present application, provides a carbon source together with the suitable mass of glucose. Hydrogen provides hydrogen atoms, and cooperates with the suitable argon to ensure that the carbon nanorings are not excessively oxidized, and at the same time, enables the carbon nanorings to form a hollow structure. Finally, the iron powder with a specific particle size is used for ball milling to finally form carbon nanorings with a specific length, which greatly improves the photoelectric efficiency of the carbon nanorings of the present application.

[0015] The present application has the following beneficial effects:

[0016] The product prepared by the preparation method of the carbon nanorings of the present application overcomes the problem that the carbon nanotubes currently increase the contact resistance of a device due to agglomeration, thereby reducing the photoelectric efficiency of the device. The product of the present application is used as an electron transport layer of an inverted perovskite solar cell, which significantly improves the photoelectric performance of the device. The photovoltaic performance of the device modified by the carbon nanorings is obviously improved, the open-circuit voltage is 1.04 V, the EQE of the device modified by the carbon nanorings is obviously increased in the range of 550-750 nm, and the integral current of the device reaches 22.02 mA / cm 2 , which is obviously higher than 19.09 mA / cm 2 of the comparative device. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A schematic diagram of the structure of the carbon nanoring prepared by the present application.

[0018] Figure 2 A scanning electron microscope image of the carbon nanoring prepared by the present application.

[0019] Figure 3 An X-ray diffraction pattern of the carbon nanoring prepared by the present application.

[0020] Figure 4 A schematic diagram of the structure of a carbon nanoring-based perovskite solar cell device.

[0021] Figure 5 A current density-voltage characteristic curve diagram of the carbon nanoring prepared by the present application and a perovskite solar cell device based on a comparative example.

[0022] Figure 6 A photoelectric conversion efficiency characteristic curve diagram of the carbon nanoring prepared by the present application and a perovskite solar cell device based on a comparative example. DETAILED DESCRIPTION

[0023] The present application will be further described below by way of examples and with reference to the accompanying drawings.

[0024] Example 1

[0025] A preparation method of a carbon nanoring preparation method, which is prepared according to the following steps:

[0026] 1. Preparation of glucose ferrocene solution: 10 g of glucose and 0.2 g of ferrocene were respectively taken and placed in a suitable container, 100 ml of deionized water was added, stirred for 15 minutes, and dissolved to obtain the glucose ferrocene solution, and the stirring speed was 60 r / min.

[0027] 2. Hydrogenation reaction: first, the tube furnace was added to 1000℃, H2 and Ar were introduced under the condition of heat preservation, and the glucose ferrocene solution was injected into the tube furnace by a syringe, H2 and Ar were continuously introduced for 12 minutes, H2 was closed, Ar was continuously introduced, the tube furnace was stopped for heat preservation and naturally cooled to room temperature, and the product was collected; wherein the gas flow ratio of H2 and Ar is 1:17, and the volume mass ratio of H2 inflow volume to glucose per minute is 10:1.

[0028] 3. Washing and drying: the product after hydrogenation reaction was taken and placed in a suitable container, 0.5 mol / L hydrochloric acid was first added for cleaning, then ethanol was added for cleaning, and finally deionized water was added for cleaning, after cleaning, it was placed in a vacuum drying box, the vacuum degree was set to-0.07 MPa, the temperature was set to 75℃, and drying was carried out for 10 hours to obtain the dried product, which was ready for use; the mass ratio of the product after hydrogenation reaction, hydrochloric acid, ethanol and deionized water is 1:18:50:100.

[0029] 4. Ball milling: taking the dried product, placing it in a ball mill, adding iron powder, and ball milling under sealed conditions for 110 minutes to obtain a ball-milled product; wherein the mass ratio of the dried product to iron powder is 1:20, and the particle size of the iron powder is 200-400 μm.

[0030] 5. Washing and purification: placing the ball-milled product in a suitable container, adding 0.5 mol / L hydrochloric acid, soaking for 25 minutes, taking it out, placing it in deionized water, soaking for 8 minutes, placing it in a centrifuge, taking out the precipitate, placing it again in deionized water, soaking for 8 minutes, placing it in a centrifuge, taking out the centrifugal precipitate, and obtaining a centrifugal product; wherein the mass-volume ratio of the ball-milled product to hydrochloric acid is 1:18, the mass-volume ratio of the ball-milled product to deionized water is 1:20, the centrifugal speed is 7000 r / min, and the centrifugation time is 13 minutes.

[0031] 6. Drying: taking the centrifugal product obtained above, placing it in a blast drying oven, setting the temperature to 85°C, and drying for 11 hours to obtain carbon nanorings.

[0032] The carbon nanorings obtained in Example 1 were subjected to scanning electron microscopy and X-ray diffraction, and the results are shown in Figure 2 and Figure 3 .

[0033] Comparative Test 1: A method for preparing carbon nanotubes was prepared according to the following steps:

[0034] The raw material ratio was the same as that in Example 1, except that no glucose was added during the preparation process, and the ball milling step was also omitted. The other raw material ratio and step parameters were the same as those in Example 1, i.e., carbon nanotubes were prepared according to the following steps:

[0035] 1. Preparation of ferrocene solution: taking 0.2 g of ferrocene, placing it in a suitable container, adding 100 ml of deionized water, stirring for 15 minutes to dissolve, and obtaining a ferrocene solution; wherein the stirring speed was 60 r / min.

[0036] 2. Hydrogenation reaction: first, the tube furnace was added to 1000°C, H2 and Ar were continuously introduced under heat preservation conditions, the ferrocene solution was injected into the tube furnace using a syringe, H2 and Ar were continuously introduced for 12 minutes, H2 was turned off, Ar was continuously introduced, the tube furnace was stopped for heat preservation and naturally cooled to room temperature, and the product was collected; wherein the gas flow ratio of H2 to Ar was 1:17, and the volume mass ratio of H2 flow per minute to glucose was 10:1.

[0037] 3. Washing and drying: the product after hydrogenation reaction is taken into a suitable container, first washed with 0.5 mol / L hydrochloric acid, then washed with ethanol, and finally washed with deionized water. After washing, the product is placed in a vacuum drying oven, the vacuum degree is set to -0.07 MPa, the temperature is set to 75℃, and the product is dried for 10 hours to obtain the dried product, which is carbon nanotube; the mass ratio of the product after hydrogenation reaction, hydrochloric acid, ethanol and deionized water is 1:18:50:100.

[0038] The current density-voltage characteristics and photoelectric conversion efficiency characteristics of the carbon nanorings prepared in Example 1 and the carbon nanotubes prepared in Comparative Test 1 are determined, and the determination results are specifically shown in Figure 5 and Figure 6 As shown in the figures, the photovoltaic performance of the carbon nanorings prepared in Example 1 is obviously improved, the open circuit voltage is 1.04 V, the EQE of the carbon nanorings modified device is obviously increased in the range of 550-750 nm, and the integral current of the device reaches 22.02 mA / cm 2 , which is also obviously higher than 19.09 mA / cm 2 of the carbon nanotubes prepared in Comparative Test 1.

[0039] Example 2

[0040] A preparation method of a carbon nanoring is prepared by the following steps:

[0041] 1. Preparation of glucose ferrocene solution: 10 g of glucose and 0.2 g of ferrocene are taken into a suitable container, 100 ml of deionized water is added, stirred for 10 minutes, and dissolved to obtain a glucose ferrocene solution, and the stirring speed is 70 r / min.

[0042] 2. Hydrogenation reaction: first, the tube furnace is added to 950℃, H2 and Ar are continuously introduced under the condition of heat preservation, the glucose ferrocene solution is injected into the tube furnace by a syringe, H2 and Ar are continuously introduced for 10 minutes, H2 is closed, Ar is continuously introduced, the tube furnace is stopped for heat preservation and naturally cooled to room temperature, and the product is collected; wherein the gas flow ratio of H2 and Ar is 1:17, and the volume mass ratio of H2 inflow volume to glucose per minute is 10:1.

[0043] 3. Washing and drying: the product after hydrogenation reaction is taken into a suitable container, first washed with 0.5 mol / L hydrochloric acid, then washed with ethanol, and finally washed with deionized water. After washing, the product is placed in a vacuum drying oven, the vacuum degree is set to -0.05 MPa, the temperature is set to 80℃, and the product is dried for 10 hours to obtain the dried product, which is carbon nanotube; the mass ratio of the product after hydrogenation reaction, hydrochloric acid, ethanol and deionized water is 1:15:40:80.

[0044] 4. Ball milling: the dried product was placed in a ball mill, iron powder was added, and the mixture was ball-milled for 100 minutes under a sealed condition to obtain a ball-milled product; the mass ratio of the dried product to the iron powder was 1:20, and the particle size of the iron powder was 200-400 μm.

[0045] 5. Washing and purification: the ball-milled product was placed in a suitable container, 0.5 mol / L hydrochloric acid was added, and the mixture was soaked for 20 minutes, then taken out, placed in deionized water, soaked for 5 minutes, placed in a centrifuge, and the precipitate was taken out, then placed in deionized water again, soaked for 5 minutes, placed in a centrifuge, and the precipitate was taken out again to obtain a centrifuged product; the mass-volume ratio of the ball-milled product to the hydrochloric acid was 1:15, the mass-volume ratio of the ball-milled product to the deionized water was 1:20, the centrifugation speed was 6000 r / min, and the centrifugation time was 10 minutes.

[0046] 6. Drying: the centrifuged product was placed in a blast drying oven, the temperature was set to 80°C, and the product was dried for 10 hours, and then the drying was completed to obtain carbon nanorings.

[0047] The carbon nanorings prepared in Example 2 were subjected to current density-voltage characteristic determination and photoelectric conversion efficiency characteristic determination, and the open-circuit voltage was 1.05 V. The EQE of the carbon nanoring modified device was obviously increased in the range of 550-750 nm, and the integral current of the device reached 22.03 mA / cm 2 .

[0048] Example 3

[0049] A preparation method of a carbon nanoring is prepared according to the following steps:

[0050] 1. Preparation of a glucose ferrocene solution: 10 g of glucose and 0.2 g of ferrocene were placed in a suitable container, 100 ml of deionized water was added, and the mixture was stirred at a speed of 50 r / min for 20 minutes until the glucose ferrocene solution was prepared.

[0051] 2. Hydrogenation reaction: a tubular furnace was first heated to 1050°C, H2 and Ar were continuously introduced under a heat preservation condition, a glucose ferrocene solution was injected into the tubular furnace using a syringe, H2 and Ar were continuously introduced for 15 minutes, H2 was turned off, the tubular furnace was allowed to stop heating and naturally cooled to room temperature, and the product was collected; the gas flow ratio of H2 to Ar was 1:17, and the volume mass ratio of the H2 inflow volume to the glucose per minute was 10:1.

[0052] 3. Washing and drying: the product after hydrogenation reaction is placed in a suitable container, first washed with 0.5 mol / L hydrochloric acid, then washed with ethanol, and finally washed with deionized water. After washing, the product is placed in a vacuum drying oven, the vacuum degree is set to -0.08 MPa, the temperature is set to 70℃, and the product is dried for 12 hours to obtain a dried product. The mass ratio of the product after hydrogenation reaction, hydrochloric acid, ethanol and deionized water is 1:20:60:120.

[0053] 4. Ball milling: the dried product is placed in a ball mill, and iron powder is added. The product is ball milled under sealed conditions for 120 minutes to obtain a ball-milled product. The mass ratio of the dried product to iron powder is 1:20, and the particle size of the iron powder is 200-400 μm.

[0054] 5. Washing and purification: the ball-milled product is placed in a suitable container, 0.5 mol / L hydrochloric acid is added, and the mixture is soaked for 30 minutes. The mixture is taken out, placed in deionized water, and soaked for 10 minutes. The mixture is placed in a centrifuge, the precipitate is taken out, and the precipitate is again placed in deionized water and soaked for 10 minutes. The mixture is placed in a centrifuge again, the centrifugal precipitate is taken out, and a centrifugal product is obtained. The mass-volume ratio of the ball-milled product to hydrochloric acid is 1:20, the mass-volume ratio of the ball-milled product to deionized water is 1:20, the centrifugal speed is 8000 r / min, and the centrifugation time is 10 minutes.

[0055] 6. Drying: the centrifugal product obtained in the above step is placed in a blast drying oven, the temperature is set to 90℃, and the product is dried for 10 hours to obtain carbon nanorings.

[0056] The carbon nanorings prepared in Example 3 are subjected to current density-voltage characteristic determination and photoelectric conversion efficiency characteristic determination. The open circuit voltage is 1.04 V, the EQE of the carbon nanoring modified device is significantly increased in the range of 550-750 nm, and the integral current of the device reaches 22.05 mA / cm 2 .

Claims

1. A method for preparing a carbon nanoring, characterized by, It is prepared by using glucose, ferrocene, deionized water and hydrogen as raw materials, respectively preparing glucose ferrocene solution, hydrogenation reaction, washing and drying, ball milling, washing and purifying, and drying; wherein the mass ratio of the glucose, ferrocene and deionized water is 50:1:500; the ball milling is to take the dried product, put it into a ball mill, add iron powder, and ball mill for 100-120 minutes under sealed condition to obtain the ball-milled product; wherein the mass ratio of the dried product and the iron powder is 1:20, and the particle size of the iron powder is 200-400 μm.

2. The method of claim 1, wherein the carbon nanorings are formed by the steps of: The glucose ferrocene solution is prepared by taking glucose and ferrocene, respectively, putting them into a suitable container, adding deionized water, stirring for 10-20 minutes, and dissolving to obtain the glucose ferrocene solution; the stirring speed is 50-70 r / min. ​ 3. The method of claim 2, wherein the carbon nanorings are formed by the steps of: The hydrogenation reaction is to heat a tubular furnace to 950-1050 ℃, continuously pass H2 and Ar under the condition of heat preservation, inject the glucose ferrocene solution into the tubular furnace by using a syringe, continuously pass H2 and Ar for 10-15 minutes, close the H2, continue to pass Ar, stop the heat preservation of the tubular furnace, and naturally cool to room temperature to collect the product; wherein the gas flow ratio of H2 and Ar is 1:17, and the volume mass ratio of the H2 inflow volume to glucose per minute is 10:

1. ​ 4. The method of claim 3, wherein the carbon nanorings are formed by the steps of: The washing and drying is to take the product after the hydrogenation reaction, put it into a suitable container, first wash with 0.5 mol / L hydrochloric acid, then wash with ethanol, and finally wash with deionized water, place it in a reduced pressure drying oven after washing, set the vacuum degree to -0.05 MPa to -0.08 MPa and the temperature to 70-80 ℃, dry for 8-12 hours to obtain the dried product; the mass ratio of the product after the hydrogenation reaction, the hydrochloric acid, the ethanol and the deionized water is 1:15-20:40-60:80-120. ​ 5. The method of claim 4, wherein the carbon nanorings are formed by the steps of: The washing and purifying is to take the ball-milled product, put it into a suitable container, add 0.5 mol / L hydrochloric acid, soak for 20-30 minutes, take it out, put it into deionized water, soak for 5-10 minutes, put it into a centrifuge, take out the precipitate, put it into deionized water again, soak for 5-10 minutes, put it into a centrifuge again, take out the centrifugal precipitate to obtain the centrifugal product; the mass volume ratio of the ball-milled product and the hydrochloric acid is 1:15-20, the mass volume ratio of the ball-milled product and the deionized water is 1:20, and the centrifugal speed is 6000-8000 r / min, and the centrifugal time is 10-15 minutes. ​ 6. The method of claim 5, wherein the carbon nanorings are formed by the steps of: The drying is to take the centrifugal product, put it into an air drying oven, set the temperature to 80-90 ℃, and dry for 10-12 hours to obtain the carbon nanoring. ​

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