A perovskite solar cell, its carbon paste, and preparation method

Abstract

The present invention provides a perovskite solar cell, its carbon paste, and a preparation method. The carbon paste of the perovskite solar cell includes the following components: graphite powder, carbon black, ethyl cellulose, terpineol, and zirconium propoxide. By adding zirconium propoxide, the adhesion of the carbon paste of the perovskite solar cell of the present invention is greatly increased, thereby improving the adhesion of the carbon back electrode and optimizing the performance of the perovskite solar cell.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and particularly relates to a perovskite solar cell, its carbon paste, and a preparation method thereof. Background Art

[0002] Due to the good power conversion efficiency (PCE) and very low material cost of perovskite solar cells (PSCs), they are considered a promising photovoltaic technology. The reason why perovskite solar cells have high photovoltaic performance is due to their high optical absorption characteristics and balanced charge transport characteristics with long diffusion lengths.

[0003] The back electrodes of traditional perovskite solar cells are noble metals such as Au and Ag. These raw materials are expensive and will react with perovskite. Therefore, using a low-cost and stable back electrode has become one of the important research directions. Since the work function of carbon materials (-5.0 eV) is close to that of Au (-5.1 eV), and carbon materials are inexpensive and abundant in source, replacing the noble metal Au with carbon materials as the back electrode of perovskite cells has become a better choice for large-scale industrial production of perovskite solar cells.

[0004] Currently, perovskite solar cells mainly consist of FTO glass, a titanium dioxide dense layer, a titanium dioxide mesoporous layer, a zirconium oxide spacer layer, a perovskite layer, and a carbon back electrode. However, due to the poor mechanical properties of carbon materials and insufficient adhesion to FTO glass, and the carbon back electrode being in the last layer of printing, when testing, the testing instrument is connected to the FTO glass and the carbon electrode respectively, resulting in the carbon electrode being easily peeled off from the FTO glass, thus leading to extremely poor test results of the power conversion efficiency of perovskite cells, and directly affecting the conductivity of the carbon electrode, thereby affecting the fill factor of perovskite cells. Summary of the Invention

[0005] The technical problem to be solved by the present invention is the insufficient mechanical properties of the carbon back electrode in the prior art.

[0006] To solve the above technical problem, the technical solution of the present invention is as follows:

[0007] A carbon paste for a perovskite solar cell, comprising the following components: graphite powder, carbon black, ethyl cellulose, terpineol, zirconium propoxide.

[0008] Preferably, the carbon paste for the perovskite solar cell comprises the following components in parts by weight:

[0009]

[0010] The present invention also provides a method for preparing a carbon paste for a perovskite solar cell, which comprises the following steps: taking graphite powder, carbon black, ethyl cellulose, terpineol, ethanol, mixing them evenly, and adding zirconium propoxide thereto to obtain a mixture; then, ball-milling the mixture and mixing it evenly to obtain the carbon paste for the perovskite solar cell.

[0011] Preferably, the weight ratio of the ethanol to the terpineol is (1.5 - 3):1.

[0012] Preferably, the method for preparing the carbon paste for the perovskite solar cell specifically comprises the following steps: taking graphite powder, carbon black, ethyl cellulose, adding terpineol and ethanol thereto, and then adding zirconium propoxide thereto to obtain a mixture; then, ball-milling the mixture for 24 - 72 h, and then rotary-evaporating to remove the ethanol, and mixing the mixture evenly by using a three-roll mill to obtain the carbon paste for the perovskite solar cell.

[0013] The present invention also provides a perovskite solar cell, which uses the carbon paste for the perovskite solar cell to prepare a carbon back electrode.

[0014] Preferably, the perovskite solar cell includes an FTO glass, a titanium dioxide dense layer, a titanium dioxide mesoporous layer, a zirconium oxide spacer layer, a perovskite layer, and a carbon back electrode which are sequentially arranged. Among them, the FTO glass is a fluorine-doped SnO2 transparent conductive glass.

[0015] The present invention also provides a method for preparing a perovskite solar cell, which comprises the following steps:

[0016] (1) Taking an FTO glass as a substrate, and spraying titanium dioxide on the FTO glass to form a titanium dioxide dense layer;

[0017] (2) Printing titanium dioxide on the titanium dioxide dense layer to form a titanium dioxide mesoporous layer;

[0018] (3) Printing zirconium oxide on the titanium dioxide mesoporous layer to form a zirconium oxide spacer layer;

[0019] (4) Taking the carbon paste obtained by the method for preparing the carbon paste for the perovskite solar cell, and printing the carbon paste on the zirconium oxide spacer layer to form a carbon back electrode;

[0020] (5) Taking a perovskite solution, coating the perovskite solution on the carbon back electrode, and after crystallization, forming a perovskite layer between the carbon back electrode and the zirconium oxide to obtain the perovskite solar cell.

[0021] Preferably, in step (4), the carbon paste is screen-printed on the zirconium oxide spacer layer and fired at 350 - 450 °C for 0.5 - 3 h to form a carbon back electrode.

[0022] Preferably, in step (4), the thickness of the carbon back electrode is 20 - 50 microns.

[0023] Preferably, in step (5), the perovskite solution is methylammonium lead iodide solution (MAPbI3).

[0024] The above - mentioned solution of the present invention has at least the following beneficial effects:

[0025] (1) The carbon paste of the perovskite solar cell of the present invention comprises the following components: graphite powder, carbon black, ethyl cellulose, terpineol, zirconium n - propoxide. By adding zirconium n - propoxide, the adhesiveness of the carbon paste is greatly increased, thereby improving the adhesiveness of the carbon back electrode and optimizing the performance of the perovskite solar cell.

[0026] Among them, in the carbon paste, zirconium n - propoxide undergoes the following hydrolysis reaction with water in the air:

[0027] Zr(OCH2 CH2 CH3)4 + 4H2O → Zr(OH)2 + 4CH3 CH2 CH2OH

[0028] The reaction produces zirconium hydroxide. On the one hand, zirconium hydroxide has strong viscosity, which can increase the adhesiveness of the carbon paste. On the other hand, zirconium hydroxide has high compatibility with zirconia. When the carbon paste is printed on the zirconia spacer layer formed by zirconia, a firm bond can be formed. At the same time, due to the increase in the viscosity of the carbon paste, the contact between graphite and graphite, and between graphite and carbon black becomes closer, thus improving the electron - transport channels, further increasing the conductivity of the carbon back electrode and reducing the internal resistance of the carbon back electrode. Therefore, the fill factor of the perovskite cell can be improved, enabling the perovskite solar cell to work efficiently.

[0029] (2) The preparation method of the carbon paste of the perovskite solar cell of the present invention is to mix graphite powder, carbon black, ethyl cellulose, and terpineol evenly, and add zirconium n - propoxide thereto to obtain a mixture; then, ball - mill the mixture. During the ball - milling process, the hydrolysis reaction of zirconium n - propoxide proceeds fully to form zirconium hydroxide, which is evenly distributed in the carbon paste. After ball - milling, the viscosity of the carbon paste increases significantly. Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of the perovskite solar cell in Example 1 of the present invention;

[0031] Figure 2 is the current - voltage diagram of the perovskite solar cell in Example 1 of the present invention;

[0032] Among them, 1. Carbon back electrode; 2. Perovskite layer; 3. Zirconia spacer layer; 4. Titanium dioxide mesoporous layer; 5. Titanium dioxide dense layer; 6. FTO glass. Detailed implementation mode

[0033] In each embodiment of the present invention, those without specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments without indicating the manufacturer can be obtained through commercial purchase, and raw materials of different manufacturers and models do not affect the implementation of the technical solution of the present invention and the realization of the technical effect.

[0034] Example 1

[0035] The carbon paste of the perovskite solar cell in this example includes the following components in parts by weight:

[0036]

[0037] The preparation method of the carbon paste of the perovskite solar cell in this example includes the following steps:

[0038] According to the selected parts by weight, take graphite powder, carbon black, and ethyl cellulose, add terpineol and ethanol to it, and then add zirconium propoxide to obtain a mixture; wherein, the weight ratio of the ethanol to the terpineol is 2:1.

[0039] Ball-mill the mixture for 48 h, then rotary evaporate to remove ethanol, and then use a three-roll mill to mix the mixture evenly to obtain the carbon paste of the perovskite solar cell.

[0040] The perovskite solar cell in this example uses the obtained carbon paste of the perovskite solar cell as the carbon back electrode. As Figure 1 shown, it specifically includes an FTO glass 6, a titanium dioxide dense layer 5, a titanium dioxide mesoporous layer 4, a zirconia spacer layer 3, a perovskite layer 2, and a carbon back electrode 1 arranged in sequence.

[0041] The preparation method of the perovskite solar cell described in this example includes the following steps:

[0042] (1) Take FTO glass as the substrate, and spray titanium dioxide on the FTO glass to form a titanium dioxide dense layer;

[0043] (2) Screen-print titanium dioxide on the titanium dioxide dense layer to form a titanium dioxide mesoporous layer;

[0044] (3) Screen-print zirconia on the titanium dioxide mesoporous layer to form a zirconia spacer layer;

[0045] (4) Take the carbon paste prepared in this embodiment, screen-print the carbon paste on the zirconia spacer layer, and sinter it at 400 °C for 0.7 h to form a carbon back electrode; the thickness of the carbon back electrode is 30 microns.

[0046] (5) Take the perovskite solution, and coat the perovskite solution on the carbon back electrode by drop coating. The perovskite solution is a lead iodide methylamine solution. After crystallization, a perovskite layer is formed between the carbon back electrode and the zirconia, and thus a perovskite solar cell is obtained.

[0047] Example 2

[0048] The carbon paste of the perovskite solar cell in this embodiment comprises the following components in parts by weight:

[0049]

[0050] The preparation method of the carbon paste of the perovskite solar cell in this embodiment comprises the following steps:

[0051] According to the selected parts by weight, take graphite powder, carbon black, and ethyl cellulose, add terpineol and ethanol thereto, and then add zirconium propoxide thereto to obtain a mixture; wherein, the weight ratio of the ethanol to the terpineol is 3:1.

[0052] Ball-mill the mixture for 24 h, then rotary evaporate to remove the ethanol, and then use a three-roll mill to mix the mixture evenly to obtain the carbon paste of the perovskite solar cell.

[0053] The perovskite solar cell in this embodiment uses the carbon paste of the perovskite solar cell obtained above as the carbon back electrode, which specifically includes an FTO glass, a titanium dioxide dense layer, a titanium dioxide mesoporous layer, a zirconia spacer layer, a perovskite layer, and a carbon back electrode arranged in sequence.

[0054] The preparation method of the perovskite solar cell in this embodiment comprises the following steps:

[0055] (1) Take an FTO glass as a substrate, spray titanium dioxide on the FTO glass to form a titanium dioxide dense layer;

[0056] (2) Screen-print titanium dioxide on the titanium dioxide dense layer to form a titanium dioxide mesoporous layer;

[0057] (3) Screen-print zirconia on the titanium dioxide mesoporous layer to form a zirconia spacer layer;

[0058] (4) Take the carbon paste prepared in this embodiment, screen-print the carbon paste on the zirconia spacer layer, and sinter it at 350 °C for 0.5 h to form a carbon back electrode; the thickness of the carbon back electrode is 50 microns.

[0059] (5) Take the perovskite solution, and coat the perovskite solution on the carbon back electrode by drop coating. The perovskite solution is a lead iodide methylamine solution. After crystallization, a perovskite layer is formed between the carbon back electrode and the zirconia, and thus a perovskite solar cell is obtained.

[0060] Example 3

[0061] The carbon paste of the perovskite solar cell in this embodiment comprises the following components in parts by weight:

[0062]

[0063] The preparation method of the carbon paste of the perovskite solar cell in this embodiment comprises the following steps:

[0064] According to the above-selected parts by weight, take graphite powder, carbon black, and ethyl cellulose, add terpineol and ethanol thereto, and then add zirconium propoxide thereto to obtain a mixture; wherein, the weight ratio of the ethanol to the terpineol is 1.5:1.

[0065] Ball-mill the mixture for 72 h, then rotary evaporate to remove the ethanol, and then use a three-roll mill to mix the mixture evenly to obtain the carbon paste of the perovskite solar cell.

[0066] The perovskite solar cell in this embodiment uses the obtained carbon paste of the perovskite solar cell as the carbon back electrode, which specifically includes an FTO glass, a titanium dioxide dense layer, a titanium dioxide mesoporous layer, a zirconia spacer layer, a perovskite layer, and a carbon back electrode arranged in sequence.

[0067] The preparation method of the perovskite solar cell described in this embodiment comprises the following steps:

[0068] (1) Take an FTO glass as the substrate, and spray titanium dioxide on the FTO glass to form a titanium dioxide dense layer;

[0069] (2) Screen-print titanium dioxide on the titanium dioxide dense layer to form a titanium dioxide mesoporous layer;

[0070] (3) Screen-print zirconia on the titanium dioxide mesoporous layer to form a zirconia spacer layer;

[0071] (4) Take the carbon paste prepared in this embodiment, screen-print the carbon paste on the zirconia spacer layer, and sinter it at 450 °C for 3 h to form a carbon back electrode; the thickness of the carbon back electrode is 20 microns.

[0072] (5) Take the perovskite solution, and coat the perovskite solution on the carbon back electrode by drop coating. The perovskite solution is a lead iodide methylamine solution. After crystallization, a perovskite layer is formed between the carbon back electrode and the zirconia, and thus a perovskite solar cell is obtained.

[0073] Example 4

[0074] The carbon paste of the perovskite solar cell in this embodiment includes the following components in parts by weight:

[0075]

[0076]

[0077] The preparation method of the carbon paste of the perovskite solar cell in this embodiment includes the following steps:

[0078] According to the selected parts by weight above, take graphite powder, carbon black, and ethyl cellulose, add terpineol and ethanol to them, and then add zirconium propoxide to obtain a mixture; wherein, the weight ratio of the ethanol to the terpineol is 2.2:1.

[0079] Ball-mill the mixture for 48 h, then rotary evaporate to remove the ethanol, and then use a three-roll mill to mix the mixture evenly to obtain the carbon paste of the perovskite solar cell.

[0080] The perovskite solar cell in this embodiment uses the obtained carbon paste of the perovskite solar cell as the carbon back electrode, which specifically includes an FTO glass, a titanium dioxide dense layer, a titanium dioxide mesoporous layer, a zirconia spacer layer, a perovskite layer, and a carbon back electrode arranged in sequence.

[0081] The preparation method of the perovskite solar cell described in this embodiment includes the following steps:

[0082] (1) Take an FTO glass as the substrate, and spray titanium dioxide on the FTO glass to form a titanium dioxide dense layer;

[0083] (2) Screen-print titanium dioxide on the titanium dioxide dense layer to form a titanium dioxide mesoporous layer;

[0084] (3) Screen-print zirconia on the titanium dioxide mesoporous layer to form a zirconia spacer layer;

[0085] (4) Take the carbon paste prepared in this example, screen-print the carbon paste onto the zirconia spacer layer, and bake it at 400 °C for 2 h to form a carbon back electrode; the thickness of the carbon back electrode is 30 microns.

[0086] (5) Take the perovskite solution, and coat the perovskite solution onto the carbon back electrode by drop coating. The perovskite solution is a lead iodide methylamine solution. After crystallization, a perovskite layer is formed between the carbon back electrode and the zirconia, and thus a perovskite solar cell is obtained.

[0087] Comparative Example 1

[0088] The carbon paste of the perovskite solar cell in this comparative example is exactly the same as that in Example 1, and the only difference is that zirconia is used instead of zirconium propoxide.

[0089] This comparative example uses the same raw materials and methods as in Example 1 to prepare a perovskite solar cell.

[0090] Comparative Example 2

[0091] The carbon paste of the perovskite solar cell in this comparative example is exactly the same as that in Example 1, and the only difference is that the weight fraction of zirconium propoxide is 1 part.

[0092] This comparative example uses the same raw materials and methods as in Example 1 to prepare a perovskite solar cell.

[0093] Comparative Example 3

[0094] The carbon paste of the perovskite solar cell in this comparative example is exactly the same as that in Example 1, and the only difference is that the weight fraction of zirconium propoxide is 25 parts.

[0095] This comparative example uses the same raw materials and methods as in Example 1 to prepare a perovskite solar cell. During the preparation process, since the obtained carbon paste is too thick, it is difficult to screen-print it onto the zirconia spacer layer, and a carbon back electrode cannot be formed.

[0096] Effect Comparative Example

[0097] To verify the technical effect of the carbon paste of the perovskite solar cell described in the present invention, the following tests are carried out:

[0098] Take the carbon paste of the perovskite solar cells obtained in Examples 1-4 and Comparative Examples 1-3, and test the resistivity of the carbon paste with a four-probe resistivity / sheet resistance tester;

[0099] Take the perovskite solar cells obtained in Examples 1-4 and Comparative Examples 1-3, and test the adhesion of the carbon back electrode with a micro-scratch tester;

[0100] Take the perovskite solar cells obtained in Examples 1-4 and Comparative Examples 1-3, and record through a solar simulator (Oriel Sol3A, Newport) and a digital source meter (Keithley 2400) to test the open-circuit voltage V oc , current density J SC , fill factor FF, and fill efficiency PCE.

[0101] The experimental results are as follows:

[0102]

[0103] From the above experimental results, it can be seen that the carbon pastes of Examples 1-4 containing zirconium propoxide can achieve better adhesion effects, while the adhesion force of Comparative Example 1 is only 209.76 mN. At the same time, from Comparative Examples 2-3 and Examples 1-4, it can be seen that when the amount of zirconium propoxide is too small, it cannot play an obvious role, while when it is excessive, the carbon paste becomes too thick and thus cannot be screen-printed into a film. Especially in Example 1, when the weight ratio of zirconium propoxide in the carbon paste is 12%, its performance is particularly prominent.

[0104] As is known by common technical knowledge, the present invention can be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A carbon paste for perovskite solar cells, characterized in that, Comprising the following components in parts by weight: 13 - 20 parts of graphite powder; 2 - 6 parts of carbon black; 3 - 6 parts of ethyl cellulose; 50 - 70 parts of terpineol; 6 - 18 parts of zirconium propoxide; In the carbon paste, the zirconium propoxide undergoes the following hydrolysis reaction with water in the air: Zr(OCH2CH2CH3)4 + 4H2O → Zr(OH)2 + 4CH3CH2CH2OH.

2. A method for preparing the carbon paste of the perovskite solar cell according to claim 1, characterized in that, Comprising the following steps: taking graphite powder, carbon black, ethyl cellulose, terpineol, and ethanol, mixing them evenly, and adding zirconium propoxide thereto to obtain a mixture; then, ball - milling the mixture and mixing it evenly to obtain the carbon paste for perovskite solar cells.

3. The preparation method of the carbon paste for perovskite solar cells according to claim 2, characterized in that, The weight ratio of the ethanol to the terpineol is (1.5 - 3):

1.

4. The preparation method of the carbon paste for perovskite solar cells according to claim 2, characterized in that, Specifically comprising the following steps: taking graphite powder, carbon black, and ethyl cellulose, adding terpineol and ethanol thereto, and then adding zirconium propoxide thereto to obtain a mixture; then, ball - milling the mixture for 24 - 72 h, then rotary - evaporating to remove the ethanol, and using a three - roll mill to mix the mixture evenly to obtain the carbon paste for perovskite solar cells.

5. A perovskite solar cell, characterized in that, Using the carbon paste for perovskite solar cells described in Claim 1 to prepare a carbon back electrode.

6. The perovskite solar cell according to claim 5, wherein, Comprising an FTO glass, a titanium dioxide dense layer, a titanium dioxide mesoporous layer, a zirconium oxide spacer layer, a perovskite layer, and a carbon back electrode arranged in sequence.

7. A method for preparing a perovskite solar cell, characterized in that, Comprising the following steps: (1) Taking an FTO glass as a substrate, spraying titanium dioxide on the FTO glass to form a titanium dioxide dense layer; (2) Printing titanium dioxide on the titanium dioxide dense layer to form a titanium dioxide mesoporous layer; (3) Printing zirconium oxide on the titanium dioxide mesoporous layer to form a zirconium oxide spacer layer; (4) Taking the carbon paste obtained by the preparation method of the carbon paste for perovskite solar cells described in any one of Claims 2 - 4, printing the carbon paste on the zirconium oxide spacer layer to form a carbon back electrode; (5) Taking a perovskite solution, coating the perovskite solution on the carbon back electrode, and after crystallization, forming a perovskite layer between the carbon back electrode and the zirconium oxide to obtain a perovskite solar cell.

8. The preparation method of the perovskite solar cell according to claim 7, wherein, In step (4), the carbon paste is screen - printed on the zirconium oxide spacer layer and fired at 350 - 450 °C for 0.5 - 3 h to form a carbon back electrode.

9. The preparation method of the perovskite solar cell according to claim 7, characterized in that, In step (4), the thickness of the carbon back electrode is 20 - 50 microns.

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