CN113394343B - Back-incident p-i-n structure perovskite solar cell and preparation method thereof - Google Patents

Abstract

The invention discloses a back-incidence p-i-n perovskite solar cell and a preparation method thereof. A copper oxide nanorod array vertically grown on a FTO substrate is used as a hole transport layer of the perovskite solar cell, and the A back-incidence perovskite solar cell with FTO as cathode and transparent composite electrode (V ₂ O ₅ /Ag/V ₂ O ₅ ) as anode was fabricated. It is found that the short-circuit current density of the back-incident p‑i‑n perovskite solar cell constructed by the copper oxide nanorod array is 23.98 mA/cm ² and the efficiency is 17.46%; Compared with the battery, the short-circuit current density and efficiency of the perovskite battery prepared by the copper oxide nanoarray hole transport layer are greatly improved, the short-circuit current density is increased by about 1.4 times, and the efficiency is increased by about 1.7 times.

Description

A back-incident p-i-n structure perovskite solar cell and preparation method thereof

technical field

The invention relates to the fields of nano-semiconductor materials and new energy sources, specifically a perovskite solar cell structure and a preparation method thereof.

Background technique

而Spiro-OMeTAD中的掺杂剂会降低电池稳定性【Science,2017,358,739；Advanced Energy Materials,2018,8,1701883】。之后，人们采用PEDOT:PSS/钙钛矿层/PC₆₁BM构筑的p-i-n型电池器件，工艺相对简单，而且薄膜退火温度较低以及J-V迟滞效应较小逐渐引起了广泛的兴趣。这种器件结构的光电转换效率略低与n-i-p结构器件，目前PEDOT:PSS/钙钛矿层/PC₆₁BM结构器件效率已经超过18％【Energy&EnvironmentalScience,2015,8,1602】。空穴传输层的主要作用是收集并传输从钙钛矿薄膜层注入的光生空穴，从而实现电子-空穴的有效分离，是钙钛矿太阳电池的重要组成部分，然而，这种p-i-n器件结构中通常使用的PEDOT:PSS有机空穴传输层并不是很理想，因为其电子阻挡性能力并非完美而且其功函数相对较低(-5.0eV)，从而导致开路电压通常在0.95-1.0V之间；另一方面，PEDOT:PSS具有酸性，很容易腐蚀导电玻璃电极，不利于空穴的收集，也降低了器件的稳定性【Nanoscale,2016,8,11403；】。所以寻找更好的空穴传输材料代替有机PEDOT:PSS材料是钙钛矿太阳电池的重要研究方向之一。The solar cell prepared based on the hybrid perovskite structure material (CH ₃ NH ₃ PbI ₃ ) synthesized by organic methylamine and inorganic lead iodide is due to its high photoelectric conversion efficiency (the highest efficiency has exceeded 22% at present), relatively The advantages of low cost and easy preparation have gained widespread attention [Nature, 2019, 567, 511]. At present, most high-performance perovskite solar cells adopt a nip-type device structure constructed with a _TiO2 mesoporous layer/perovskite layer/hole transport layer. _TiO2 requires high temperature preparation

The dopants in Spiro-OMeTAD will reduce the battery stability [Science, 2017, 358, 739; Advanced Energy Materials, 2018, 8, 1701883]. Afterwards, the use of PEDOT:PSS/perovskite layer/PC ₆₁ BM to build pin-type battery devices has gradually attracted widespread interest. The photoelectric conversion efficiency of this device structure is slightly lower than that of nip structure devices, and the current PEDOT:PSS/perovskite layer/PC ₆₁ BM structure device efficiency has exceeded 18% [Energy & Environmental Science, 2015, 8, 1602]. The main role of the hole transport layer is to collect and transport the photo-generated holes injected from the perovskite thin film layer, thereby realizing the effective separation of electrons and holes, which is an important part of perovskite solar cells. However, this pin device The PEDOT:PSS organic hole transport layer commonly used in the structure is not ideal because its electron blocking ability is not perfect and its work function is relatively low (-5.0eV), resulting in an open circuit voltage typically between 0.95-1.0V. On the other hand, PEDOT:PSS is acidic, which can easily corrode the conductive glass electrodes, which is not conducive to the collection of holes, and also reduces the stability of the device [Nanoscale, 2016, 8, 11403;]. Therefore, finding better hole transport materials to replace organic PEDOT:PSS materials is one of the important research directions of perovskite solar cells.

Compared with the traditional organic hole transport layer, the p-type semiconductor copper oxide material has the characteristics of abundant sources, low cost, air stability and simple preparation process; more importantly, the valence band energy level of copper oxide and CH ₃ NH ₃ PbI ₃ The energy levels of the ions are very matched, which can realize the efficient injection and transport of holes, which has been successfully used in the hole transport layer of perovskite solar cells [Journal of Materials Chemistry A, 2017, 5, 20381]. However, it is not difficult to find that in the current research on perovskite solar cells, the copper oxide used as the hole transport layer is all a planar thin film structure, which greatly limits the active contact area between perovskite and copper oxide.

For example, the existing patent CN111463349A discloses a method for improving the stability of perovskite solar cells, but this patent uses a copper oxide film (the contact area between copper oxide and perovskite is small), and it is the bottom incident structure. At bottom incidence, since copper oxide itself absorbs visible light, which affects the photon acquisition of perovskite films, the top incidence structure avoids such a problem.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a perovskite solar cell and a preparation method thereof, which are used to solve the problem that the contact area between the hole transport layer and the perovskite of the existing p-i-n perovskite solar cell is limited, thereby causing the perovskite solar cell. The problem of photogenerated hole collection loss.

The technical scheme of the present invention to solve the technical problem is:

A back-incidence p-i-n structure perovskite solar cell sequentially includes a cathode, a copper oxide array, a perovskite light absorption layer, an electron transport layer, and an anode.

The cathode is transparent conductive glass.

The transparent conductive glass is one of fluorine tin oxide, indium tin oxide and aluminum zinc oxide.

The perovskite light absorbing layer is selected from one of CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBr ₃ or CH ₃ NH ₃ PbI _x Br _1-x thin films.

The electron transport layer is PC ₆₁ BM.

The anode is a transparent composite electrode (V ₂ O ₅ /Ag/V ₂ O ₅ ).

The preparation method of the back incident p-i-n structure perovskite solar cell includes the following steps:

(1) Treatment of FTO conductive film;

(2) Preparation of copper oxide nanoarray hole transport layer;

(3) Preparation of perovskite light absorption layer;

(4) Preparation of electron transport layer;

(5) Preparation of transparent composite electrodes.

The preparation steps of the copper oxide nano-array hole transport layer are as follows:

(1) copper acetate is dissolved in ethanol, the blue clear transparent solution that stirs at room temperature obtains;

(2) above-mentioned solution is spin-coated on clean FTO conductive glass by a gluer to obtain a uniform copper acetate film;

(3) annealing in a muffle furnace to obtain a dense copper oxide film;

(4) placing it in an aqueous solution composed of copper nitrate trihydrate and hexamethylenetetramine, sealing and reacting in a 90° C. oven for 1-2 hours to obtain a copper oxide nanorod array.

The perovskite light absorbing layer is a CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer, and its specific preparation method is as follows: (1) CH ₃ NH ₂ and PbI ₂ are added to an organic mixed solvent, and the organic mixed The solvent is prepared from γ-butyrolactone and dimethyl sulfoxide in a volume ratio of 7:3; then a yellow clear perovskite precursor solution is obtained by stirring;

(2) The perovskite precursor solution was spin-coated on the copper oxide nanorod array obtained in the above step using a glue spinner in a nitrogen glove box, and the substrate was annealed with a heating plate in a nitrogen glove box to obtain CH ₃ NH ₃ PbI3 _perovskite light absorbing layer.

The specific preparation method of the electron transport layer is as follows:

(1) dissolve PC ₆₁ BM powder in chlorobenzene;

(2) spin-coating the above solution on the CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer through a glue spinner in a nitrogen glove box;

(3) The substrate was annealed with a heating plate in a nitrogen glove box.

In the present invention, we use copper oxide nanoarrays to replace the copper oxide thin film, which will greatly increase the contact area between copper oxide and perovskite, so that the photo-generated holes in perovskite may be better separated and transferred; at the same time, Nanorod arrays provide direct hole transport channels, which can reduce the degree of interfacial charge recombination, which will further improve the optoelectronic performance of perovskite solar cells. In addition, the geometric size and spatial distribution of the array are not easily changed during use, which avoids the change of the morphological structure of the photoactive layer under the illumination temperature, and increases the stability of the structure and performance of the battery. We replaced the conventional top metal electrode with a transparent electrode (V ₂ O ₅ /Ag/V ₂ O ₅ ), and obtained a back-incidence pin-structured perovskite solar cell with copper oxide nanoarrays as the hole transport layer.

The beneficial effects of the present invention are:

(1) The present invention prepares a back-incident pin perovskite solar cell by using a copper oxide array to replace the current conventional flat film as a hole transport layer, which can significantly improve the photocurrent of the cell. In the present invention, the flat copper oxide film is used as the hole transport layer, and the short-circuit current density and efficiency of the battery are 16.71 mA/cm ² and 10.21% respectively; using the traditional flat PEDOT:PSS film as the hole transport layer, the battery has a The short-circuit current density and efficiency are 16.35 mA/cm ² and 10.56%, respectively; while using the copper oxide array as the hole transport layer, the short-circuit current density and efficiency of the battery can reach 23.98 mA/cm ² and 17.46%, and the battery performance is significantly enhanced .

(2) In the present invention, the copper oxide array is used as the hole transport layer, which can greatly increase the contact area between the copper oxide and the perovskite, so that the photogenerated holes in the perovskite may be better separated and transferred. The hole collection performance improves the photocurrent of the cell.

(3) The back-incidence p-i-n perovskite solar cell in the present invention is simple in preparation method, low in equipment requirements, suitable for large-scale application, and has great application value in the fields of photovoltaic materials and low-cost solar cell devices.

Description of drawings

Figure 1 is a schematic structural diagram of a back-incidence pin perovskite solar cell of the present invention; the numbers in the figure are marked as follows: 1, cathode; 2, copper oxide nanoarray hole transport layer; 3, CH ₃ NH ₃ PbI ₃ calcium Titanite light absorption layer; 4. Electron transport layer; 5. Anode.

FIG. 2 is the current-voltage performance of a back-incident p-i-n perovskite solar cell under illumination (AM1.5) provided by the embodiment of the present invention. Among them, (a) is the current-voltage performance of the cell using 1h copper oxide nanoarrays as hole transport layer under illumination (AM 1.5), namely Example 1; (b) is using 1.5h copper oxide nanoarrays as holes The current-voltage performance of the transport layer cell under illumination (AM 1.5), namely Example 2; (c) is the current-voltage performance of the cell using 2h copper oxide nanoarrays as the hole transport layer under illumination (AM 1.5). , namely Example 3.

FIG. 3 is the current-voltage performance of a back-incident p-i-n perovskite solar cell provided by the comparative example of the present invention under illumination (AM1.5). Among them, (a) is the current-voltage performance of the battery using copper oxide nanofilm as the hole transport layer under illumination (AM 1.5), that is, Comparative Example 1; (b) is the battery using PEDOT:PSS film as the hole transport layer. Current-voltage performance under illumination (AM 1.5), ie, Comparative Example 2.

Detailed ways

Example 1

Treatment of FTO conductive film: The FTO conductive glass was ultrasonically cleaned with glass cleaning agent, acetone, and isopropanol, dried with nitrogen, and treated with ultraviolet-ozone for 30 minutes.

Preparation steps of copper oxide nanoarray hole transport layer:

(1) Dissolve 0.02 g of copper acetate in 10 ml of ethanol and stir at room temperature for 12 hours to obtain a blue clear and transparent solution.

(2) Spin-coating the above solution on clean FTO conductive glass at a speed of 2000 r/min through a gluing machine to obtain a uniform copper acetate film.

(3) Annealing in a muffle furnace at 350° C. for 30 minutes obtains a dense copper oxide film.

(4) placing it in an aqueous solution composed of 0.25 mol/L copper nitrate trihydrate and 0.25 mol/L hexamethylenetetramine, sealing and reacting in a 90° C. oven for 1 hour to obtain a copper oxide nanorod array.

Preparation steps of CH ₃ NH ₃ PbI ₃ perovskite light absorption layer:

(1) 209 mg of CH ₃ NH ₂ and 581 mg of PbI ₂ were added to 1 ml of an organic mixed solvent prepared from γ-butyrolactone and dimethyl sulfoxide in a volume ratio of 7:3. Then stirred at 80 °C for 2 h to obtain a yellow clear perovskite precursor.

(2) The perovskite precursor solution was spin-coated on the copper oxide nanorod array obtained in the above step using a glue spinner in a nitrogen glove box, and the substrate was annealed with a heating plate in a nitrogen glove box to obtain CH ₃ NH ₃ PbI3 _perovskite light absorption layer, the annealing temperature is 80 °C, and the annealing time is 10 minutes.

Preparation steps of the electron transport layer:

(1) 15 mg of PC ₆₁ BM powder was dissolved in 1 ml of chlorobenzene.

(2) The above solution was spin-coated on the CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer at a speed of 2000 rpm in a nitrogen glove box through a glue spinner.

(3) The substrate is annealed with a heating plate in a nitrogen glove box, the annealing temperature is 80° C., and the annealing time is 5 minutes.

Preparation of transparent composite electrode: V ₂ O ₅ with a thickness of 10 nm was deposited on the electron transport layer by thermal evaporation in a vacuum coating chamber, then silver with a thickness of 9 nm was deposited, and finally V ₂ O ₅ with a thickness of 40 nm was deposited.

Example 2

Treatment of FTO conductive film: The FTO conductive glass was ultrasonically cleaned with glass cleaning agent, acetone, and isopropanol, dried with nitrogen, and treated with ultraviolet-ozone for 30 minutes.

Preparation steps of copper oxide nanoarray hole transport layer:

(1) Dissolve 0.02 g of copper acetate in 10 ml of ethanol and stir at room temperature for 12 hours to obtain a blue clear and transparent solution.

(2) Spin-coating the above solution on clean FTO conductive glass at a speed of 2000 r/min through a gluing machine to obtain a uniform copper acetate film.

(3) Annealing in a muffle furnace at 350° C. for 30 minutes obtains a dense copper oxide film.

(4) placing it in an aqueous solution composed of 0.25 mol/L copper nitrate trihydrate and 0.25 mol/L hexamethylenetetramine, sealing and reacting in a 90° C. oven for 1.5 hours to obtain a copper oxide nanorod array.

Preparation steps of CH ₃ NH ₃ PbI ₃ perovskite light absorption layer:

(1) 209 mg of CH ₃ NH ₂ and 581 mg of PbI ₂ were added to 1 ml of an organic mixed solvent prepared from γ-butyrolactone and dimethyl sulfoxide in a volume ratio of 7:3. Then stirred at 80 °C for 2 h to obtain a yellow clear perovskite precursor.

(2) The perovskite precursor solution was spin-coated on the copper oxide nanorod array obtained in the above step using a glue spinner in a nitrogen glove box, and the substrate was annealed with a heating plate in a nitrogen glove box to obtain CH ₃ NH ₃ PbI3 _perovskite light absorption layer, the annealing temperature is 80 °C, and the annealing time is 10 minutes.

Preparation steps of the electron transport layer:

(1) 15 mg of PC ₆₁ BM powder was dissolved in 1 ml of chlorobenzene.

(2) The above solution was spin-coated on the CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer at a speed of 2000 rpm in a nitrogen glove box through a glue spinner.

(3) The substrate is annealed with a heating plate in a nitrogen glove box, the annealing temperature is 80° C., and the annealing time is 5 minutes.

Preparation of transparent composite electrode: V ₂ O ₅ with a thickness of 10 nm was deposited on the electron transport layer by thermal evaporation in a vacuum coating chamber, then silver with a thickness of 9 nm was deposited, and finally V ₂ O ₅ with a thickness of 40 nm was deposited.

Example 3

Treatment of FTO conductive film: The FTO conductive glass was ultrasonically cleaned with glass cleaning agent, acetone, and isopropanol, dried with nitrogen, and treated with ultraviolet-ozone for 30 minutes.

Preparation steps of copper oxide nanoarray hole transport layer:

(1) Dissolve 0.02 g of copper acetate in 10 ml of ethanol and stir at room temperature for 12 hours to obtain a blue clear and transparent solution.

(2) Spin-coating the above solution on clean FTO conductive glass at a speed of 2000 r/min through a gluing machine to obtain a uniform copper acetate film.

(3) Annealing in a muffle furnace at 350° C. for 30 minutes obtains a dense copper oxide film.

(4) placing it in an aqueous solution composed of 0.25 mol/L copper nitrate trihydrate and 0.25 mol/L hexamethylenetetramine, sealing and reacting in a 90° C. oven for 2 hours to obtain a copper oxide nanorod array.

Preparation steps of CH ₃ NH ₃ PbI ₃ perovskite light absorption layer:

(1) 209 mg of CH ₃ NH ₂ and 581 mg of PbI ₂ were added to 1 ml of an organic mixed solvent prepared from γ-butyrolactone and dimethyl sulfoxide in a volume ratio of 7:3. Then stirred at 80 °C for 2 h to obtain a yellow clear perovskite precursor.

(2) The perovskite precursor solution was spin-coated on the copper oxide nanorod array obtained in the above step using a glue spinner in a nitrogen glove box, and the substrate was annealed with a heating plate in a nitrogen glove box to obtain CH ₃ NH ₃ PbI3 _perovskite light absorption layer, the annealing temperature is 80 °C, and the annealing time is 10 minutes.

Preparation steps of the electron transport layer:

(1) 15 mg of PC ₆₁ BM powder was dissolved in 1 ml of chlorobenzene.

(2) The above solution was spin-coated on the CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer at a speed of 2000 rpm in a nitrogen glove box through a glue spinner.

(3) The substrate is annealed with a heating plate in a nitrogen glove box, the annealing temperature is 80° C., and the annealing time is 5 minutes.

Preparation of transparent composite electrode: V ₂ O ₅ with a thickness of 10 nm was deposited on the electron transport layer by thermal evaporation in a vacuum coating chamber, then silver with a thickness of 9 nm was deposited, and finally V ₂ O ₅ with a thickness of 40 nm was deposited.

Comparative Example 1

Comparative Example 1 is a back-incidence p-i-n perovskite solar cell prepared with a copper oxide nano-film hole transport layer.

Treatment of FTO conductive film: The FTO conductive glass was ultrasonically cleaned with glass cleaning agent, acetone, and isopropanol, dried with nitrogen, and treated with ultraviolet-ozone for 30 minutes.

Preparation steps of copper oxide nano-film hole transport layer:

(1) Dissolve 0.02 g of copper acetate in 10 ml of ethanol and stir at room temperature for 12 hours to obtain a blue clear and transparent solution.

(2) Spin-coating the above solution on clean FTO conductive glass at a speed of 2000 r/min through a gluing machine to obtain a uniform copper acetate film.

(3) Annealing in a muffle furnace at 350° C. for 30 minutes obtains a dense copper oxide film.

Preparation steps of CH ₃ NH ₃ PbI ₃ perovskite light absorption layer:

(1) 209 mg of CH ₃ NH ₂ and 581 mg of PbI ₂ were added to 1 ml of an organic mixed solvent prepared from γ-butyrolactone and dimethyl sulfoxide in a volume ratio of 7:3. Then stirred at 80 °C for 2 h to obtain a yellow clear perovskite precursor.

(2) The perovskite precursor solution was spin-coated on the copper oxide nanofilm obtained in the above step by using a glue spinner in a nitrogen glove box, and the substrate was annealed with a heating plate in a nitrogen glove box to obtain CH ₃ NH ₃ PbI ₃ The perovskite light absorption layer, the annealing temperature is 80°C, and the annealing time is 10 minutes.

Preparation steps of the electron transport layer:

(1) 15 mg of PC ₆₁ BM powder was dissolved in 1 ml of chlorobenzene.

(2) The above solution was spin-coated on the CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer at a speed of 2000 rpm in a nitrogen glove box through a glue spinner.

(3) The substrate is annealed with a heating plate in a nitrogen glove box, the annealing temperature is 80° C., and the annealing time is 5 minutes.

Preparation of transparent composite electrode: V ₂ O ₅ with a thickness of 10 nm was deposited on the electron transport layer by thermal evaporation in a vacuum coating chamber, then silver with a thickness of 9 nm was deposited, and finally V ₂ O ₅ with a thickness of 40 nm was deposited.

Comparative Example 2

Comparative Example 2 is a back-incidence p-i-n perovskite solar cell prepared with a PEDOT:PSS organic thin film hole transport layer.

Treatment of FTO conductive film: The FTO conductive glass was ultrasonically cleaned with glass cleaning agent, acetone, and isopropanol, dried with nitrogen, and treated with ultraviolet-ozone for 30 minutes.

Preparation steps of PEDOT:PSS organic hole transport layer: First, filter the PEDOT:PSS solution with a 0.45 μm filter head, and then use a spin coater to spin-coat the PEDOT:PSS solution on a clean FTO conductive substrate under air. The coating speed is 4500 rpm and the time is 60s. Then, heat treatment was performed at 145° C. for 10 minutes under air to obtain a PEDOT:PSS film layer as a hole transport layer.

Preparation steps of CH ₃ NH ₃ PbI ₃ perovskite light absorption layer:

(1) 209 mg of CH ₃ NH ₂ and 581 mg of PbI ₂ were added to 1 ml of an organic mixed solvent prepared from γ-butyrolactone and dimethyl sulfoxide in a volume ratio of 7:3. Then stirred at 80 °C for 2 h to obtain a yellow clear perovskite precursor.

(2) The perovskite precursor solution was spin-coated on the copper oxide nanofilm obtained in the above step by using a glue spinner in a nitrogen glove box, and the substrate was annealed with a heating plate in a nitrogen glove box to obtain CH ₃ NH ₃ PbI ₃ The perovskite light absorption layer, the annealing temperature is 80°C, and the annealing time is 10 minutes.

Preparation steps of the electron transport layer:

(1) 15 mg of PC ₆₁ BM powder was dissolved in 1 ml of chlorobenzene.

(2) The above solution was spin-coated on the CH ₃ NH ₃ PbI ₃ perovskite light absorbing layer at a speed of 2000 rpm in a nitrogen glove box through a glue spinner.

(3) The substrate is annealed with a heating plate in a nitrogen glove box, the annealing temperature is 80° C., and the annealing time is 5 minutes.

Preparation of transparent composite electrode: V ₂ O ₅ with a thickness of 10 nm was deposited on the electron transport layer by thermal evaporation in a vacuum coating chamber, then silver with a thickness of 9 nm was deposited, and finally V ₂ O ₅ with a thickness of 40 nm was deposited.

Figure 2 shows the current-voltage (JV) performance characterization results of the perovskite solar cells prepared in Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2 under illumination (AM1.5). The JV test was done in an air room temperature environment; the short-circuit current density and efficiency of the perovskite cells fabricated from the copper oxide nanofilm hole transport layer ^were 16.71 mA/cm and 10.21%, respectively. The short-circuit current density and efficiency of the perovskite cells fabricated from the PEDOT:PSS nanofilm hole transport layer ^were 16.35 mA/cm and 10.56%, respectively. Compared with perovskite cells prepared from copper oxide nanofilms and PEDOT:PSS organic thin film hole transport layers, the short-circuit current density and efficiency of perovskite cells prepared with copper oxide nanoarray hole transport layers are greatly improved. Detailed comparison See Table 1.

Table 1.

Note: JV performance test is done in laboratory environment, the effective area of the battery is 16mm ² ; V _oc , J _sc , FF and η are the open circuit voltage, short circuit current, fill factor and conversion efficiency of the battery, respectively.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Those skilled in the art can make various corresponding changes according to the present invention without departing from the spirit and essence of the present invention. and deformation, but these corresponding changes and deformations should belong to the protection scope of the appended claims of the present invention.

Claims (8)

1. A preparation method of a back-incident p-i-n structure perovskite solar cell is characterized by comprising the following steps:

processing an FTO conductive film;

preparing a copper oxide nano array hole transport layer;

preparing a perovskite light absorption layer;

preparing an electron transport layer;

preparing a transparent composite electrode;

the preparation steps of the copper oxide nano array hole transport layer are as follows:

(1) dissolving copper acetate in ethanol, and stirring at room temperature to obtain a blue clear transparent solution;

(2) spin-coating the solution on clean FTO conductive glass through a spin coater to obtain a uniform copper acetate film;

(3) annealing in a muffle furnace to obtain a compact copper oxide film;

(4) placing the copper oxide nano-rod array in an aqueous solution consisting of copper nitrate trihydrate and hexamethylenetetramine, sealing, and reacting in an oven at 90 ℃ for 1-2 hours to obtain a copper oxide nano-rod array;

the back incidence p-i-n structure perovskite solar cell sequentially comprises an anode, a copper oxide array, a perovskite light absorption layer, an electron transmission layer and a back incidence cathode from bottom to top.

2. The method for preparing a back-incident p-i-n structural perovskite solar cell as claimed in claim 1, wherein: the cathode is transparent conductive glass.

3. The method for preparing a back-incident p-i-n structural perovskite solar cell as claimed in claim 2, wherein: the transparent conductive glass is one of fluorine tin oxide, indium tin oxide and aluminum zinc oxide.

4. The method for preparing a back-incident p-i-n structural perovskite solar cell as claimed in claim 1, wherein: the perovskite light absorption layer is selected from CH ₃ NH ₃ PbI ₃ Or CH ₃ NH ₃ PbBr ₃ One type of film.

5. The method for preparing a back-incident p-i-n structural perovskite solar cell as claimed in claim 1, wherein: the electronic transmission layer is PC ₆₁ BM。

6. The method for preparing a back-incident p-i-n structural perovskite solar cell as claimed in claim 1, wherein: the anode is a transparent composite electrode V ₂ O ₅ /Ag/V ₂ O ₅ 。

7. The method for preparing a back-incident p-i-n perovskite solar cell as claimed in claim 1, wherein the perovskite light absorption layer is CH ₃ NH ₃ PbI ₃ The perovskite light absorption layer is prepared by the following specific steps:

(1) will CH ₃ NH ₂ And PbI ₂ Adding into an organic mixed solvent consisting of

Butyrolactone and dimethyl sulfoxide in a volume ratio of 7: 3, preparing; then stirring to obtain yellow clear perovskite precursor liquid;

(2) spin-coating the perovskite precursor solution on the copper oxide nanorod array obtained in the step by using a spin coater in a nitrogen glove box, and annealing the substrate by using a heating plate in the nitrogen glove box to obtain CH ₃ NH ₃ PbI ₃ A perovskite light absorbing layer.

8. The method for preparing a perovskite solar cell with a back incidence p-i-n structure according to claim 1, wherein the electron transport layer is prepared by the following specific method:

(1) will PC ₆₁ BM powder is dissolved in chlorobenzene;

(2) spin-coating the above solution on CH in a nitrogen glove box by a spin coater ₃ NH ₃ PbI ₃ A perovskite light-absorbing layer;

(3) the substrate was annealed using a hot plate in a nitrogen glove box.

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