Perovskite solar cell based on electrode wire embedding technology and preparation method thereof

Abstract

The invention discloses a perovskite solar cell based on an electrode wire embedding technology and a preparation method thereof. The perovskite solar cell comprises glass, and an FTO layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a hole barrier layer and a silver electrode which are sequentially arranged on the surface of the glass. The FTO layer is provided with a first insulating groove filled with a first insulating material; the hole transport layer, the perovskite light absorption layer, the electron transport layer and the hole blocking layer are provided with conductive grooves penetrating to the surface of the glass, the conductive grooves are filled with conductive materials, and the conductive grooves and the silver electrodes form conductive circuits. According to the invention, the conventional laser etching process is replaced by a photoetching process and the like, and the perovskite solar cell is prepared through an electrode wire embedding technology. And the electrode wire embedding technology can avoid thermal damage, eliminate the thermal degradation risk of the perovskite and the organic transmission layer caused by laser high temperature, and improve the stability of the device. And the efficiency of the battery assembly is improved. And the preparation process is simplified.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and specifically relates to a method for preparing a high-stability, low-cost perovskite solar cell by using electrode embedding technology to optimize the interface contact and charge transfer efficiency of the perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells have become a research hotspot in the photovoltaic field due to their high photoelectric conversion efficiency (>26%) and low-cost solution preparation. Among them, laser scribing is the core process in the preparation of perovskite solar cell modules. Figure 1 As shown, this technique is primarily used to separate cell regions to form a tandem structure (P1 / P2 / P3 process). However, the following issues exist: The high temperature of laser scribing can cause thermal deformation of the film or volatilization of the material, affecting cell efficiency. This is because the thermal damage caused by laser scribing is essentially localized high-temperature ablation, meaning that local temperatures can reach 200–400°C, far exceeding the perovskite decomposition threshold. This can lead to material decomposition, lattice damage, and interface failure. Perovskite material decomposition: Localized high temperatures caused by laser scribing can cause the loss of iodine (I) or bromine (Br), forming inactive lead halide phases (such as PbI2), reducing light absorption and carrier generation efficiency. The A-site cations (methylamine and formamidine) in the perovskite are easily volatilized at high temperatures, leading to stoichiometric imbalance. Lattice structure destruction: Localized high temperatures can cause the perovskite lattice to collapse, forming amorphous regions or detrimental phases (such as δ-phase perovskite), increasing the density of defect states and causing non-radiative recombination. Interface damage - laser heat may diffuse to adjacent electron transport layers (such as TiO2, SnO2, C60) or hole transport layers (such as Spiro-OMeTAD, PTAA, NiOx), causing changes in their crystallinity or degradation of their chemical properties (such as oxidation or decomposition). Electrode damage - If P3 scribing involves metal electrodes (such as Ag, Au), excessive laser energy may cause local melting of the electrodes or reduced adhesion to the substrate; multi-layer etching must be completed in steps, requiring extremely high equipment accuracy and process stability; the scribing width is typically 30-100μm, and the occupied area reduces the effective active area by about 3-5%; the investment and maintenance costs of laser equipment are high, and additional material residue processing is required after etching.

[0003] Therefore, there is an urgent need for a cell preparation method that can optimize the interface contact of perovskite solar cells and simplify the process. Summary of the Invention

[0004] In order to solve the technical problems of high-temperature damage caused by laser scribing when the existing laser scribing divides the perovskite solar cell areas to form a series structure, which affects the cell efficiency; the manufacturing process is complicated and the cost is high, the present invention provides a perovskite solar cell with simplified manufacturing, good stability, high efficiency and low cost, and a preparation method thereof.

[0005] The present invention provides a perovskite solar cell based on buried electrode technology, comprising glass and an FTO layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a hole blocking layer, and a silver electrode, sequentially disposed on the surface of the glass. The FTO layer is provided with a first insulating groove filled with a first insulating material; the hole transport layer, perovskite light absorption layer, electron transport layer, and hole blocking layer are provided with a conductive groove extending through the glass surface, filled with a conductive material and forming a conductive circuit with the silver electrode.

[0006] Preferably, the first insulating groove and the conductive groove are made by photolithography, and the silver electrode is covered on the surface of the hole blocking layer by screen printing or inkjet printing.

[0007] Preferably, the silver electrode is a silver electrode layer provided on the surface of the hole blocking layer, and the hole transport layer, perovskite light absorption layer, electron transport layer, hole blocking layer and silver electrode layer are provided with a second insulating groove penetrating to the surface of the FTO layer, and the second insulating groove is filled with a second insulating material and covers the surface of the silver electrode layer to form an encapsulation layer.

[0008] Preferably, the first insulating trench, the conductive trench and the second insulating trench are all prepared by a photolithography process or a nanoimprint process.

[0009] The present invention provides a method for preparing a perovskite solar cell based on electrode embedding technology, comprising the following steps:

[0010] Step 1: prepare a first insulating groove 8 on the surface of the FTO layer on the cleaned glass, and fill the first insulating groove with a first insulating material as an isolation layer for the buried electrode;

[0011] Step 2: sequentially preparing a hole transport layer and a perovskite layer on the surface of the FTO layer, and annealing them at 100° C. for 15 to 25 minutes; and then evaporating a hole transport layer and a hole blocking layer on the surface of the perovskite layer;

[0012] Step 3: Prepare conductive grooves that penetrate the surface of the FTO layer in the hole transport layer, perovskite layer, electron transport layer and hole blocking layer, fill the conductive grooves with conductive material, and then anneal at 100°C for 5 to 15 minutes to solidify; prepare a silver electrode on the surface of the hole blocking layer so that the conductive material forms a conductive circuit with the silver electrode, thereby obtaining the perovskite solar cell based on electrode buried wire technology.

[0013] Preferably, the first insulating groove and the conductive groove are prepared by photolithography; and the silver electrode is covered on the surface of the hole blocking layer by inkjet printing or screen printing.

[0014] Preferably, the silver electrode is a silver electrode layer evaporated on the surface of the hole blocking layer, and a second insulating groove penetrating to the surface of the FTO layer is prepared in the hole transport layer, perovskite light absorption layer, electron transport layer, hole blocking layer and silver electrode layer, and the second insulating groove is filled with a second insulating material and covered on the surface of the silver electrode layer 7, and then annealed at 100°C for 5 to 15 minutes to obtain an encapsulation layer.

[0015] Preferably, the conductive material is a non-conjugated organic free radical conductive polymer.

[0016] Preferably, the non-conjugated organic free radical conductive polymer is dispersed in isopropyl alcohol to form a solution, which is then spin-coated on the surface of the hole blocking layer to fill the conductive grooves.

[0017] Preferably, the second insulating material is one of polymethyl methacrylate, polyvinyl acetate, and ethyl cellulose.

[0018] Preferably, the polymethyl methacrylate insulating polymer is dispersed in isopropyl alcohol to form a solution, which is then spin-coated on the surface of the silver electrode layer to form a packaging layer and simultaneously fill the second insulating groove.

[0019] The present invention adopts a photolithography process to replace the existing laser etching process, and prepares perovskite solar cells through electrode embedding technology. The electrode embedding technology can avoid thermal damage: eliminate the risk of thermal degradation of perovskite and organic transport layer due to high laser temperature, and improve device stability. Improved precision: Photolithography can achieve submicron line width (<30μm), reduce dead zone area, and improve battery component efficiency. Simplified process: One-step forming of the embedded structure can reduce the multi-step alignment steps of laser scribing. Material compatibility: The conductive groove can be adapted to the low-temperature solution method (such as conductive polymer solution coating) and is suitable for flexible devices. At the same time as the electrode is embedded, an encapsulation layer 11 is covered on the surface of the silver electrode layer 7, which serves as an insulating hydrophobic layer to improve the stability of the battery. The perovskite solar cell prepared by the same photolithography process combined with nanoimprinting, nanoprinting or inkjet printing process also has better performance than the perovskite solar cell prepared by the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the cross-sectional structure of a battery using laser scribing to prepare grooves in the prior art;

[0021] Figure 2 Schematic diagram of the cross-sectional structure of the battery of Example 1 and Example 2 of the present invention;

[0022] Figure 3 Schematic diagram of the preparation process of batteries according to Examples 1 and 2 of the present invention;

[0023] Figure 4The current-voltage JV curves of the batteries of Example 1 and the comparative example are shown.

[0024] In the figure: 1-glass, 2-FTO layer, 3-hole transport layer, 4-perovskite light absorption layer, 5-electron transport layer, 6-hole blocking layer, 7-silver electrode layer, 8-first insulating trench, 9-conductive trench, 10-second insulating trench, 11-encapsulation layer. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation of the present invention.

[0026] like Figure 2 As shown, the present invention provides a perovskite solar cell based on electrode buried wire technology, comprising glass 1 and an FTO layer 2 provided on the surface of the glass, referred to as FTO glass, and a hole transport layer 3, a perovskite light absorption layer 4, an electron transport layer 5, a hole blocking layer 6 and a silver electrode layer 7 provided on the surface of the FTO layer 2 in sequence. NiOx (nickel oxide) is usually used as the hole transport layer 3, C60 (fullerene material) is used as the electron transport layer 5, and BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) is used as the hole blocking layer 6. Among them, the FTO layer 2 is prepared with a first insulating groove 8 with a depth of 500-800nm ​​and a width of 10-20μm. That is, the depth of the first insulating groove is actually the thickness of the FTO layer, which is equivalent to the insulating groove penetrating to the surface of the glass 1. The insulating groove is filled with a first insulating material. Conductive trenches 9 are formed in the hole transport layer 3, perovskite light absorbing layer 4, electron transport layer 5, and hole blocking layer 6, extending through the surface of the FTO layer 2. The depth of the conductive trenches is 500-600 nm and the width is 20-30 μm. The conductive trenches are filled with a conductive material, which can be a non-conjugated organic free radical conductive polymer. A second insulating trench 10 is also formed in the hole transport layer 3, perovskite light absorbing layer 4, electron transport layer 5, hole blocking layer 6, and silver electrode layer 7, extending through the surface of the FTO layer 2. The depth of the second insulating trenches is 610-710 nm and the width is 10-20 μm. The second insulating trenches are filled with a second insulating material and extend over the surface of the silver electrode layer 7 as an encapsulation layer 11. The second insulating material can be one of polymethyl methacrylate, polyvinyl acetate, and ethyl cellulose. The first insulating trench 8, conductive trench 9, and second insulating trench 10 are all prepared by photolithography or nanoimprinting.

[0027] The present invention also provides another perovskite solar cell based on electrode embedding technology, please refer to Figure 2, comprising glass 1 and an FTO layer 2, a hole transport layer 3, a perovskite light absorbing layer 4, an electron transport layer 5, a hole blocking layer 6, and a silver electrode sequentially disposed on the surface of the glass. The FTO layer 2 is provided with a first insulating groove 8 filled with a first insulating material; the hole transport layer 3, the perovskite light absorbing layer 4, the electron transport layer 5, and the hole blocking layer 6 are provided with a conductive groove 9 extending through the surface of the glass 1. The silver electrode is coated on the surface of the hole blocking layer 6 by inkjet printing or screen printing and forms a conductive circuit with the conductive material.

[0028] Please combine Figure 3 The present invention provides a first method for preparing a perovskite solar cell based on electrode embedding technology, comprising the following steps:

[0029] Step 1: Spin-coat a photoresist layer (positive photoresist) onto the surface of the cleaned FTO layer 2 of the FTO glass. Then, use a mask to expose the pattern of an insulating trench on the FTO layer 2, forming a first insulating trench 8. This trench has a width of 10-20 μm and a depth of approximately 500-800 nm, reaching the surface of the underlying glass 1. After the mask exposure process, the photoresist material in the exposed area outside the first insulating trench 8 is removed by the developer, leaving the photoresist in the first insulating trench 8 as the first insulating material. Because the photoresist material itself is an insulating material, it serves as an isolation layer for the buried electrode.

[0030] The photoresist used usually contains the following three components:

[0031] 1. Polymer materials (also known as resins, such as phenolic formaldehyde). Phenolic formaldehyde does not react chemically under light irradiation. Its main function is to ensure the adhesion and corrosion resistance of the photoresist film. It also determines other properties of the photoresist film, such as the film thickness requirements, elasticity requirements, and thermal stability requirements.

[0032] 2. Photosensitive material (diazonaphthoquinone). Photosensitive materials are generally composite materials (abbreviated as PAC or photosensitive agent). Diazonaphthoquinone undergoes a chemical reaction after exposure to light. The photosensitive agent of positive photoresist inhibits dissolution in unexposed areas, slowing the dissolution rate of the photoresist in the developer. Taking positive photoresist as an example, the positive photoresist used in g-ray and i-ray lithography is composed of diazoquinone (abbreviated as DQ) photosensitive agent and phenolic resin.

[0033] 3. Solvent (such as propylene glycol methyl ether, PGME). The role of the solvent is to keep the photoresist in liquid state before coating it on the silicon wafer surface.

[0034] During processing and manufacturing, the above solvent can be evenly mixed with the polymer material and the photosensitive material, and then coated on the surface of the FTO layer 2 of the FTO glass.

[0035] Step 2: A NiOx hole transport layer 3 with a thickness of 8 nm was prepared on the FTO layer 2 by magnetron sputtering, and a perovskite layer 4 was prepared by VCD (vacuum drying equipment) method, and annealed at 100°C for 15 to 25 minutes. A C60 hole transport layer 5 with a thickness of 20 nm and a BCP hole blocking layer 6 with a thickness of 3 nm were then sequentially evaporated on the surface of the perovskite layer 4.

[0036] Step 3: Etch a conductive groove 9 through the hole transport layer 3, perovskite light absorbing layer 4, electron transport layer 5 and hole blocking layer 6 to the surface of the FTO layer 2, with a width of 20-30 μm and a depth of 500-600 nm. After filling the conductive groove with a conductive material, annealing at 100°C for 5 to 15 minutes is performed to solidify. Specifically, the pattern of the conductive groove 9 is defined on the surface of the hole blocking layer 6 by photolithography (ultraviolet exposure + development), and then chemical wet etching (such as dilute hydrochloric acid) is used to remove the NiOx / perovskite layer / C60 / BCP material in the exposed area to form a conductive groove 9. Then, a conductive material - a non-conjugated organic free radical conductive polymer (PTEO), such as 4-glycidyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl - is filled in the groove. Generally, PTEO is first dispersed in isopropyl alcohol to prepare a solution, which is then spin-coated on the surface of the hole blocking layer 6. The exposed area is filled by capillary action, that is, the conductive grooves 9 are completely filled. After the solvent evaporates, the solution is annealed and solidified.

[0037] Step 4: A silver electrode layer 7 with a thickness of 110 nm is evaporated on the surface of the hole blocking layer 6. A second insulating trench 10 with a width of 10-20 μm and a depth of 610-710 nm is then etched through the hole transport layer 3, perovskite light absorbing layer 4, electron transport layer 5, hole blocking layer 6, and silver electrode layer 7 to the surface of the FTO layer 2. A second insulating material is applied to the surface of the silver electrode layer 7, and after finishing, the layer is annealed at 100°C for 5-15 minutes to produce the perovskite solar cell based on the electrode embedding technology. During the specific production process, the pattern of the second conductive trench 10 is defined on the silver electrode layer 7 by photolithography (UV exposure + development). Subsequently, a silver etchant is used to remove the NiOx / perovskite layer / C60 / BCP / silver material in the exposed area, followed by de-resist and cleaning to form the second insulating trench 10. The silver etchant has a ratio of HNO3:H2O = 1:10. A second insulating material is then applied to the surface of the silver electrode layer 7. For example, an insulating polymer solution of polymethyl methacrylate (PMMA) or isopropyl alcohol is spin-coated onto the silver electrode layer 7, and the second insulating grooves 10 are filled by capillary action. The second insulating material covering the surface of the silver electrode layer 7 forms the battery encapsulation layer 11. After the solvent evaporates, the second insulating material is annealed at 100°C for 5 to 15 minutes to solidify. In addition to PMMA, polyvinyl acetate or ethyl cellulose can also be used as the second insulating material. This step not only forms sub-batteries connected in series but also provides encapsulation and protection for the battery surface, thereby improving battery stability.

[0038] During the above preparation process, an annealing treatment at 100°C is required. The temperature of 100°C is suitable for annealing the perovskite layer of the device. In other words, annealing at 100°C is a key step that is conducive to inducing perovskite crystallization and will not cause damage to the device.

[0039] The present invention provides a second method for preparing a perovskite solar cell based on an embedded electrode technology. The steps are identical to steps 1 through 3 of the first method for preparing a perovskite solar cell. The difference is that after the conductive grooves 9 are prepared and filled with a conductive material, silver electrodes are directly formed on the surface of the hole blocking layer 6 by inkjet printing or screen printing. The silver electrodes and the conductive material form a conductive circuit. This cell does not have the second insulating groove 10 or the cell encapsulation layer 11 formed of a second insulating material covering the surface of the silver electrode layer 7.

[0040] The perovskite solar cell of the present invention uses electrode embedding technology instead of laser scribing. The electrode embedding technology is designed to achieve a lossless cell structure by patterned filling. The electrode embedding technology of the present invention involves three parts:

[0041] 1. In order to divide the transparent electrode (FTO) into independent strip areas, lay the foundation for subsequent series connection, prevent short circuits between battery cells, and determine the width of a single sub-battery (which directly affects the current size of the component).

[0042] 2. In order to realize the series connection of adjacent sub-cells, the top electrode (such as a metal silver electrode) of the previous sub-cell is connected to the bottom FTO electrode of the next sub-cell through the buried wire two channels to form a series circuit, thereby increasing the overall voltage of the battery assembly (the voltages of each sub-cell are superimposed in series).

[0043] 3. To achieve the independence of the top electrode of each sub-cell and prevent direct short circuit between adjacent sub-cells through the top electrode, the embedded wire part 1 and the embedded wire part 2 above complete the integrated structure of "single cell → series group" and play a role in protecting the battery and improving the stability of the device;

[0044] The three buried wires are connected in series without external wires, thereby reducing resistance loss.

[0045] The following is an example of using the preparation method provided by the present invention to produce a perovskite solar cell based on electrode embedding technology.

[0046] Example 1

[0047] like Figure 2 and Figure 3 As shown, a photolithography method is used to prepare an inverted perovskite solar cell. The preparation method is as follows:

[0048] a. The FTO glass was ultrasonically cleaned once with glass detergent, twice with deionized water, and twice with ethanol. The ultrasonic time for each step was 20 minutes, and then treated under UV ozone for 30 minutes.

[0049] b. Using photolithography, prepare a first insulating trench 8 on a clean FTO glass, which is filled with insulating material as an isolation layer for the buried electrode. The method is as follows: spin-coat photoresist (positive photoresist) on the surface of the FTO layer 2, and then expose the pattern of the first insulating trench 8 through a mask to form a first insulating trench 8 with a width of 10-20 μm and a depth of 500-800 μm. The trench touches the surface of the underlying glass 1, as shown in FIG. Figure 2 As shown. After the insulating trench pattern is exposed through a mask, the photoresist (e.g., phenol formaldehyde) embedded in the first insulating trench 8 serves as the first insulating material and does not require annealing. If another first insulating material, such as a polymer solution, is used to fill the first insulating trench 8, annealing is required.

[0050] c. A NiOx (nickel oxide) hole transport layer 3 was deposited on the surface of the FTO layer 2 filled with the first insulating material. An 8nm thick NiOx layer was deposited using magnetron sputtering with an oxygen flow rate of 5%. A perovskite layer 4 was deposited on the surface of the hole transport layer 3 using a vacuum drying device (VCD) method and annealed at 100°C for 15-25 minutes. A 20nm thick C60 hole transport layer 5 and a 3nm thick BCP hole blocking layer 6 were then deposited on the surface of the perovskite layer 4.

[0051] d. A conductive groove 9 pattern is prepared on the surface of the BCP-hole blocking layer 6 by photolithography (UV exposure + development), and then the four layers of NiOx / perovskite layer / C60 / BCP above the FTO layer 2 are removed by chemical wet etching (such as dilute hydrochloric acid) to obtain a conductive groove 9 with a width of 20-30 μm and a depth of 500-600 nm. The groove touches the surface of the FTO layer 2 below. Figure 2 As shown, the conductive material—a non-conjugated organic free radical conducting polymer (PTEO), such as 4-glycidyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl—is then filled. PTEO is first dispersed in isopropyl alcohol to form a solution. This PTEO solution is then spin-coated onto the BCP-hole blocking layer 6, filling the conductive trenches 9 through capillary action. After the solvent evaporates, the film is annealed at 100°C for 5-15 minutes to solidify.

[0052] e. A silver (Ag) electrode layer 7 with a thickness of 110 nm was evaporated on the surface of the BCP-hole blocking layer 6 .

[0053] f. Prepare a second insulating groove 8 pattern on the surface of the silver (Ag) electrode layer 7 by photolithography (UV exposure + development), use a silver etching solution (HNO3:H2O=1:10) to remove the five layers of NiOx / perovskite layer / C60 / BCP / Ag above the FTO layer 2, and then remove the glue and clean to obtain a second insulating groove 10 with a width of 10-20 μm and a depth of 610-710 nm. The groove touches the surface of the FTO layer 2, as shown in FIG. Figure 2 As shown. A second insulating material, such as polymethyl methacrylate (PMMA), an insulating polymer solution containing isopropyl alcohol as the solvent, is then spin-coated onto the silver electrode layer 7, filling the second insulating grooves 10 through capillary action. The second insulating material covering the surface of the silver electrode layer 7 forms the battery encapsulation layer 11. After the solvent evaporates, the layer is annealed at 100°C for 5-15 minutes to solidify. This step not only forms interconnected sub-cells but also provides surface protection for the cell, improving cell stability. This results in a trans-structured perovskite solar cell.

[0054] Example 2

[0055] like Figure 2 and Figure 3As shown, the inverted perovskite solar cell is prepared using nanoimprint technology, and the preparation method is as follows:

[0056] a. The FTO glass was ultrasonically cleaned once with glass detergent, twice with deionized water, and twice with ethanol. The ultrasonic time for each step was 20 minutes, and then treated under UV ozone for 30 minutes.

[0057] b. Prepared by nanoimprinting technology. Align the nanoimprint template of the imprinter with the FTO glass, heat the imprinter to 100-150°C, and apply a pressure of 5-10 MPa, maintain for 5-10 minutes, cool down and demould. The groove structure is formed on the surface of the FTO layer 2 of the FTO glass, and the FTO layer is etched by reactive ion etching (O 2 / CF4 plasma) to remove the exposed FTO conductive area, that is, to remove the FTO residual layer in the embossed groove area, to obtain a first insulating groove 8 with a width of 30 to 40 μm and a depth of 500 to 800 μm. The groove touches the surface of the glass 1, such as Figure 2 A first insulating material, such as a polymer material (polyimide) solution, is spin-coated to fill the first insulating trench 8, with the solvent being N,N-dimethylacetamide, and then annealed at 100° C. for 10 minutes.

[0058] c. Prepare a NiOx (nickel oxide)-hole transport layer 3 on the surface of the FTO layer 2, and use the magnetron sputtering method to prepare 8nm NiOx with an oxygen flow rate of 5%; prepare a perovskite layer 4 on the FTO / NiOx substrate using the VCD (vacuum drying equipment) method and anneal at 100°C for 15 to 25 minutes; evaporate a C60-hole transport layer 5 with a thickness of 20nm and a BCP-hole blocking layer 6 with a thickness of 3nm on the FTO / NiOx / perovskite substrate.

[0059] d. Using nanoimprint technology, align the nanoimprint template with the FTO / NiOx / perovskite / C60 / BCP substrate. Apply pressure (5-10 MPa) and temperature (approximately 100°C) in a heated imprint press for 5-10 minutes. After cooling and demolding, a groove structure is formed, directly resulting in a conductive trench 9 with a depth of 500-600 nm and a width of 50-70 μm. This trench touches the surface of the FTO layer 2, and the material within the trench will follow the template and detach. Spin-coat the conductive material by filling the conductive trench 9 with a conductive polymer solvent (4-glycidyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl) in isopropyl alcohol. Anneal the surface at 100°C for 5-15 minutes.

[0060] e. A silver (Ag) electrode layer 7 with a thickness of 110 nm was evaporated on the surface of the BCP-hole blocking layer 6 .

[0061] f. Using nanoimprint technology, align the nanoimprint template with the FTO / NiOx / perovskite / C60 / BCP / Ag substrate. Apply pressure (5-10 MPa) and temperature (approximately 100°C) in a heated imprint press for 5-10 minutes. After cooling and demolding, a groove structure is formed on the surface. The material within the groove will follow the template and detach. A second insulating trench 10 with a width of 30-40 μm and a depth of 610-710 nm is formed, contacting the surface of the FTO layer 2. A second insulating material, such as polymethyl methacrylate (PMMA) in an isopropyl alcohol solvent, is spin-coated onto the silver electrode layer 7. Capillary action fills the second insulating trench 10, while the second insulating material covering the surface of the silver electrode layer 7 forms the battery encapsulation layer 11. After the solvent evaporates, the layer is annealed at 100°C for 5-15 minutes to cure. This results in a trans-structured perovskite solar cell.

[0062] The silver electrodes in the above-mentioned embodiments 1 and 2 are formed by evaporating a silver electrode layer 7 that fully covers the BCP layer 6, wherein the second insulating groove 10 and the second insulating material can prevent short circuits and enable the sub-cells to form a series structure.

[0063] Example 3

[0064] Please refer to Figure 2 and Figure 3 , using photolithography and printing buried line technology to prepare inverted structure perovskite solar cells, the preparation method is as follows:

[0065] a. The FTO glass was ultrasonically cleaned once with glass detergent, twice with deionized water, and twice with ethanol. The ultrasonic time for each step was 20 minutes, and then treated under UV ozone for 30 minutes.

[0066] b. Using photolithography, a first insulating trench 8 is prepared on a clean FTO glass, wherein the first insulating material is filled as an isolation layer for the buried electrode. The method is as follows: a photoresist layer (positive photoresist) is spin-coated on the surface of the FTO layer 2, and the insulating trench 8 pattern is exposed through a mask to form a first insulating trench 8 with a width of 10 to 20 μm and a depth of 500 to 800 μm. The trench touches the surface of the underlying glass 1, as shown in FIG. Figure 2 After the insulating trench pattern is exposed through a mask, the photoresist (eg, phenol formaldehyde, etc.) that is sunk into the first insulating trench 8 is used as the first insulating material.

[0067] c. Prepare a NiOx (nickel oxide)-hole transport layer 3 on the surface of the FTO layer 2, and use the magnetron sputtering method to prepare 8nm NiOx with an oxygen flow rate of 5%; prepare a perovskite layer 4 on the FTO / NiOx substrate using the VCD (vacuum drying equipment) method and anneal at 100°C for 15 to 25 minutes; evaporate a C60-hole transport layer 5 with a thickness of 20nm and a BCP-hole blocking layer 6 with a thickness of 3nm on the FTO / NiOx / perovskite substrate.

[0068] d. A conductive groove 9 pattern is prepared on the surface of the BCP-hole blocking layer 6 by photolithography (UV exposure + development), and then the four layers of NiOx / perovskite layer / C60 / BCP above the FTO layer 2 are removed by chemical wet etching (such as dilute hydrochloric acid) to obtain a conductive groove 9 with a width of 20-30 μm and a depth of 500-600 nm. The groove touches the surface of the FTO layer 2 below. Figure 2 As shown, the conductive material—a non-conjugated organic free radical conducting polymer (PTEO), such as 4-glycidyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl—is then filled. PTEO is first dispersed in isopropyl alcohol to form a solution. This PTEO solution is then spin-coated onto the BCP-hole blocking layer 6, filling the conductive trenches 9 through capillary action. After the solvent evaporates, the solution is annealed at 100°C for 5-15 minutes to solidify.

[0069] f. A silver paste is used for precision screen printing to directly form conductive line electrodes on the surface of the BCP-hole blocking layer 6. Specifically, a polyester mesh (typically 250-400 mesh, balancing resolution and silver paste thickness) is used. The electrode width is typically 50-100 μm, and the spacing matches the cell design to prevent short circuits. The silver paste is evenly applied to the screen, with a squeegee moving in a single direction at a constant speed to avoid edge diffusion caused by multiple printings. The environment is controlled at a temperature of 25±2°C and a humidity of <40% RH to prevent the silver paste from forming a skin or absorbing water. Finally, an annealing step is performed at 100°C for 15-25 minutes. The silver particles in the silver paste melt to form a conductive network of embedded electrodes. Specifically, the Ag electrode forms a mesh structure covering the BCP-hole blocking layer 6, electrically connecting to the conductive material to form a conductive line, thereby producing the inverted perovskite solar cell.

[0070] Example 4

[0071] Please refer to Figure 2 、 Figure 3 , using photolithography and inkjet printing technology to prepare inverted perovskite solar cells, the preparation method is as follows:

[0072] a. Ultrasonic cleaning of FTO glass was performed once with glass detergent, twice with deionized water, and twice with ethanol. Each ultrasonic cleaning time was 20 minutes, and then treated under UV ozone for 30 minutes.

[0073] b. Using photolithography, prepare a first insulating trench 8 on a clean FTO glass, wherein the first insulating material is filled as an isolation layer for the buried electrode. The method is as follows: spin-coat a photoresist layer (positive photoresist) on the surface of the FTO layer 2, and expose the insulating trench 8 pattern through a mask to form a first insulating trench 8 with a width of 10 to 20 μm and a depth of 500 to 800 μm. The trench touches the surface of the underlying glass 1, as shown in FIG. Figure 2 After the insulating trench pattern is exposed through a mask, the photoresist (eg, phenol formaldehyde, etc.) sunk into the first insulating trench 8 is used as the first insulating material.

[0074] c. Prepare a NiOx (nickel oxide)-hole transport layer 3 on the surface of the FTO layer, and use the magnetron sputtering method to prepare 8nm NiOx with an oxygen flow rate of 5%; prepare a perovskite layer 4 on the FTO / NiOx substrate using the VCD (vacuum drying equipment) method and anneal at 100°C for 15 to 25 minutes; evaporate a C60-hole transport layer 5 with a thickness of 20nm and a BCP-hole blocking layer 6 with a thickness of 3nm on the FTO / NiOx / perovskite substrate.

[0075] d. A pattern of a conductive groove 9 is prepared on the BCP-hole blocking layer 6 by photolithography (UV exposure + development), and then the four layers of NiOx / perovskite layer / C60 / BCP above the FTO layer 2 are removed by chemical wet etching (such as dilute hydrochloric acid) to obtain a conductive groove 9 with a width of 20-30 μm and a depth of 500-600 nm. The groove touches the surface of the FTO layer 2 below. Figure 2 As shown, the conductive material—a non-conjugated organic free radical conducting polymer (PTEO), such as 4-glycidyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl—is then filled. PTEO is first dispersed in isopropyl alcohol to form a solution. This PTEO solution is then spin-coated onto the BCP-hole blocking layer 6, filling the conductive trenches 9 through capillary action. After the solvent evaporates, the solution is annealed at 100°C for 5-15 minutes to solidify.

[0076] e. Electrode inkjet printing is performed on the surface of the BCP-hole blocking layer 6 to form conductive line electrodes. Specifically, silver nano-ink (particle size 20-50 nm, viscosity 8-12 cP, conductivity >104 S / cm) is selected and 5% ethylene glycol is added. The printing parameters are then optimized: a piezoelectric inkjet head nozzle diameter of 30 μm, a drive voltage of 20-25 V, a pulse width of 20 μs, a substrate temperature of 50-60°C (to promote solvent evaporation), and a printing resolution of 800-1200 dpi (layer thickness approximately 1 μm). After inkjet printing, low-temperature sintering is performed with a stepwise temperature increase (80°C for 10 minutes → 120°C for 20 minutes) to avoid damaging the perovskite layer 4. The silver particles in the silver paste melt to form a conductive network of embedded electrodes. Specifically, the Ag electrode forms a mesh structure covering the BCP-hole blocking layer 6, connecting to the conductive material to form a conductive line, thereby producing the inverted perovskite solar cell.

[0077] In Examples 3 and 4, a conductive network, i.e., silver electrodes, is formed on the BCP layer using screen printing and inkjet technology. Since it does not provide full coverage and prevents short circuits, the second insulating trench 10 and second insulating material are not required. The silver electrodes are similar in shape to those in Examples 1 and 2. The silver electrodes, divided by the second insulating trench, are distributed on the BCP layer, forming multiple sub-cells connected in series with the first insulating trench and the conductive trench.

[0078] Therefore, the battery principle of the four embodiments is a battery assembly obtained by connecting multiple sub-batteries in series.

[0079] The laser scribing method is used to prepare the inverted structure of the perovskite solar cell. The principle is that the laser scribing process divides the perovskite module into multiple sub-cells connected in series. Figure 1 As shown, after laser scribing P1, the subsequently deposited functional layer will directly fill the P1 trench without the need for additional filling material.

[0080] The preparation method is as follows: Figure 1 As shown:

[0081] a. The FTO glass was ultrasonically cleaned once with glass detergent, twice with deionized water, and twice with ethanol. The ultrasonic time for each step was 20 minutes, and then treated under UV ozone for 30 minutes.

[0082] b. Using laser scribing, P1 is scribed on a clean FTO layer (conductive layer) substrate, forming grooves with a depth range of 500-800μm and a width range of 80-100μm. Laser scribing is performed on the FTO substrate to prepare P1, vaporizing the material and forming grooves, dividing the entire film layer into sub-cells connected in series, forming independent strip-shaped conductive electrodes, and individual modules that can block current conduction. The functional layer material prepared subsequently will directly fill the P1 grooves.

[0083] c. A NiOx (nickel oxide) hole transport layer (bottom charge transport layer) was deposited on the FTO layer (conductive layer). An 8nm thick NiOx layer was deposited using magnetron sputtering with a 5% oxygen flow rate. A perovskite layer 4 was deposited on the FTO / NiOx substrate using a vacuum degassing device (VCD) and annealed at 100°C for 15-25 minutes. A 20nm thick C60 charge transport layer and a 3nm thick BCP top charge transport layer were then evaporated on the FTO / NiOx / perovskite substrate.

[0084] d. Using laser scribing, P2 scribing is performed on the NiOx / perovskite / C60 / BCP four-layer material to form grooves with a depth of 500-600 μm and a width of 50-80 μm.

[0085] e. A silver (Ag) electrode layer with a thickness of 110 nm was evaporated on the surface of the BCP-top charge transport layer.

[0086] f. Laser scribing was performed on the NiOx / perovskite / C60 / BCP / Ag five-layer material, forming trenches P3 with a depth of 610-710 μm and a width of 80-100 μm. After scribing, the perovskite module was divided into multiple sub-cells connected in series, thereby producing a comparative example of the inverted perovskite solar cell.

[0087] The above embodiments and comparative examples are based on a perovskite solar cell module with a width of 65 mm and a length of 70 mm, which is composed of 7 sub-cells connected in series (7 wires are buried each time), and the effective area of ​​the device is 31.2 mm 2 .

[0088] The following are samples of four embodiments of the present invention and a comparative example:

[0089] Testing tools and testing methods: The efficiency of perovskite solar cells is measured under the AM1.5G solar spectrum, and the JV characteristic curve of the photovoltaic cell is obtained through a solar simulator ( Figure 4 As shown, the horizontal axis is the open circuit voltage and the vertical axis is the short circuit current density). The solar simulator simulates the AM1.5G spectrum, and the light intensity is calibrated to 100mW / cm 2 (Standard silicon battery calibration is required) and the source meter is set to sweep voltage (usually -0.1V to 12V) for testing. The measurement results are shown in Table 1:

[0090] Table 1

[0091]

[0092] The most important metric for solar cells is the photovoltaic conversion efficiency (PCE). Specific performance parameters include fill factor (FF), open circuit voltage (VOC), and short-circuit current density (JSC). Photovoltaic characteristics can be intuitively represented by a JV curve: the value at the intersection of the curve and the vertical axis is JSC, which represents the short-circuit current density of the solar cell (obtained by dividing the short-circuit current in Table 1 by the effective area of ​​the cell. The effective area of ​​the solar cell module of the present invention is 31.2mm). 2 ), and the value of the intersection of the curve and the horizontal axis is VOC, which represents the open circuit voltage of the solar cell. The JV test principle of photovoltaic cells is mainly based on the principles of photoelectric effect and circuit analysis. The photoelectric effect means that the energy of photons will be absorbed by the semiconductor material in the photovoltaic cell and converted into electron energy, causing electrons to migrate and flow in the material to generate current. In the photovoltaic JV test, the photoelectric effect is used to apply a certain voltage to put the battery in a forward and reverse biased state, and measure its output current and voltage. During the test, the photovoltaic module is connected to a dedicated capacitor as a variable load. In the process of the photovoltaic module charging the capacitor, current and voltage sampling is performed, and the corresponding current and voltage data are recorded and drawn into a JV curve.

[0093] From the results of the photoelectric conversion efficiency (PCE) of the perovskite solar cell modules in Table 1, the efficiency of the device in Example 1 is the best. The accuracy of the photolithography process is significantly higher than that of the laser scribing (comparative example), which reduces the dead area of ​​the perovskite solar cell module and also avoids the damage to the battery functional layer caused by laser scribing, which can effectively improve the efficiency of the device. In addition, compared with the nanoimprint technology, printed buried wire technology, and inkjet printing technology of other embodiments, the photolithography method has high accuracy and simple preparation, effectively reducing the preparation cost. Through the above-mentioned battery preparation process of Example 1 and the comparative example, it can be seen that:

[0094] The buried electrode structure provides a non-thermal, high-precision alternative for the modular design of perovskite solar cells, and is particularly suitable for large-area or flexible devices that are sensitive to heat. The advantages of buried electrode technology are:

[0095] Avoid thermal damage: Eliminate the risk of thermal degradation of perovskite and organic transport layers due to high laser temperature, and improve device stability. Improved precision: Photolithography can achieve submicron line width (<30μm), reduce dead zone area, and improve battery component efficiency. Simplified process: One-step formation of buried wire structure can reduce the multi-step alignment steps of laser scribing. Material compatibility: The conductive groove can be adapted to low-temperature solution methods (such as conductive polymer solution coating) and is suitable for flexible devices. While the electrode is buried, an encapsulation layer 11 is covered on the surface of the silver electrode layer 7, which serves as an insulating hydrophobic layer to improve the stability of the battery.

[0096] Due to the long-term reliance on laser / mechanical methods in the photovoltaic field, there is a lack of basic background in microelectronics technology. In addition, some processing equipment, such as photolithography / imprinting equipment, has a low penetration rate in the field of photovoltaic technology. In addition, the poor stability of early perovskites and their difficulty in withstanding the solvent / pressure treatment of the graphic process and other historical reasons have caused the industry to be troubled by problems such as thermal damage caused by laser scribing (perovskites are heat-sensitive), burrs on the edges, grooves that are difficult to clean and easily cause short circuits, and difficulty in controlling sub-micron precision. How to solve the problem? Thinking of the advantages of high precision, low temperature and no thermal effect of photolithography / imprinting to prepare perovskite solar cells, after research, analysis and repeated practice, the above technical problems have been effectively solved.

[0097] The above description is only a specific embodiment of the present invention. It should be pointed out that any modifications, equivalent replacements and changes made within the spirit and framework of the present invention should be included in the scope of protection of the present invention.

Claims

1. A perovskite solar cell based on electrode buried wire technology, comprising glass and an FTO layer, a hole transport layer, a perovskite light absorbing layer, an electron transport layer, a hole blocking layer and a silver electrode sequentially arranged on the surface of the glass, characterized in that: The FTO layer is provided with a first insulating groove filled with a first insulating material; the hole transport layer, the perovskite light absorption layer, the electron transport layer and the hole blocking layer are provided with a conductive groove penetrating to the glass surface, the conductive groove is filled with a conductive material and forms a conductive circuit with the silver electrode.

2. The perovskite solar cell based on electrode embedding technology according to claim 1, characterized in that: The first insulating groove and the conductive groove are made by photolithography, and the silver electrode is covered on the surface of the hole blocking layer by screen printing or inkjet printing.

3. The perovskite solar cell based on electrode embedding technology according to claim 1, characterized in that: The silver electrode is a silver electrode layer provided on the surface of the hole blocking layer. The hole transport layer, perovskite light absorption layer, electron transport layer, hole blocking layer and silver electrode layer are provided with a second insulating groove penetrating to the surface of the FTO layer. The second insulating groove is filled with a second insulating material and covers the surface of the silver electrode layer to form an encapsulation layer.

4. The perovskite solar cell based on electrode embedding technology according to claim 3, characterized in that: The first insulating trench, the conductive trench and the second insulating trench are all prepared by a photolithography process or a nano-imprinting process.

5. A method for preparing a perovskite solar cell based on the electrode embedding technology according to claim 1, comprising the following steps: Step 1: preparing a first insulating groove on the surface of the FTO layer 2 on the cleaned glass 1, and filling the first insulating groove with a first insulating material as an isolation layer for the buried electrode; Step 2: sequentially preparing a hole transport layer and a perovskite layer on the surface of the FTO layer, and annealing them at 100° C. for 15 to 25 minutes; and then evaporating a hole transport layer and a hole blocking layer on the surface of the perovskite layer; Step 3: Prepare conductive grooves that penetrate the surface of the FTO layer in the hole transport layer, perovskite layer, electron transport layer and hole blocking layer, fill the conductive grooves with conductive material, and then anneal at 100°C for 5 to 15 minutes to solidify; prepare a silver electrode on the surface of the hole blocking layer so that the conductive material forms a conductive circuit with the silver electrode, thereby obtaining the perovskite solar cell based on electrode buried wire technology.

6. The preparation method according to claim 5, wherein The first insulating groove and the conductive groove are prepared by photolithography; the silver electrode is covered on the surface of the hole blocking layer by inkjet printing or screen printing.

7. The preparation method according to claim 5, wherein The silver electrode is a silver electrode layer evaporated on the surface of the hole blocking layer. A second insulating groove penetrating to the surface of the FTO layer is prepared in the hole transport layer, perovskite light absorption layer, electron transport layer, hole blocking layer and silver electrode layer. The second insulating groove is filled with a second insulating material and covered on the surface of the silver electrode layer, and then annealed at 100°C for 5 to 15 minutes to obtain an encapsulation layer.

8. The preparation method according to claim 5, wherein The conductive material is a non-conjugated organic free radical conductive polymer.

9. The preparation method according to claim 8, wherein The non-conjugated organic free radical conductive polymer is dispersed in isopropyl alcohol to form a solution, which is then spin-coated on the surface of the hole blocking layer to fill the conductive grooves.

10. The preparation method according to claim 7, wherein The second insulating material is one of polymethyl methacrylate, polyvinyl acetate, and ethyl cellulose; the polymethyl methacrylate insulating polymer is dispersed in isopropyl alcohol to form a solution, which is spin-coated on the surface of the silver electrode layer to form an encapsulation layer and fill the second insulating groove at the same time.

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