CN116867295A - A trans perovskite solar cell using cobalt oxide as a hole transport material and its preparation method - Google Patents

Abstract

The invention discloses a trans-perovskite solar cell in which cobalt oxide is used as a hole transport material and a preparation method thereof, and belongs to the technical field of methods for preparing semiconductor devices. The trans perovskite solar cell structure of the present invention consists of conductive glass, hole transport layer, perovskite absorption layer, electron transport layer, and electrode from bottom to top. The hole transport layer uses CoO _x as the hole transport material. This battery reduces the attenuation of the perovskite absorption layer and optimizes the hole transport dynamics at the interface. Combined with metal ion doping, it improves the conductivity of CoO _x and obtains better device performance, thereby improving trans-perovskite efficiency and stability of mineral solar cells. The preparation method of the invention is simple to operate, low in cost, green and environmentally friendly, and has good application prospects.

Description

A trans perovskite solar cell using cobalt oxide as a hole transport material and its Preparation

Technical field

The present invention relates to the technical field of methods for preparing semiconductor devices, and in particular to a trans perovskite solar cell using cobalt oxide as a hole transport material and a preparation method thereof.

Background technique

Perovskite solar cells (PSCs) have attracted much attention as a new generation of photovoltaic devices due to their high power conversion efficiency (PCE) and low manufacturing cost. The ambipolar semiconductor optical properties of perovskites provide the possibility to design devices with different device structures. Among them, inverted planar structures are attracting increasing attention due to their simplicity, possibility of low-temperature processing, and low hysteresis. And it shows the potential to become a commercial photovoltaic device. The hole transport layer (HTL) plays a leading role in the device performance and long-term stability of inverted perovskite solar cells (PSCs). Currently, various organic hole transport materials (HTMs) have been used, especially poly(3,4-ethylenedioxythiophene): (polystyrene sulfonate) (PEDOT: PSS) and polybis(4-phenyl) (2,4,6-trimethylphenyl)amine (PTAA). However, their complex manufacturing processes, inherent chemical volatility, poor stability, and high cost hinder their large-scale commercial application. Among them, inorganic p-type semiconductors are particularly attractive due to their high light transmittance, high hole mobility and high chemical stability. By comparison, several inorganic HTMs such as CuSCN, _NiO , _VO and WO have been used as _alternatives to organic hole transport layers. Among them, NiO _x has received widespread attention due to its high transmittance, good chemical stability, and energy level that matches perovskite, which facilitates hole collection and electron blocking. Therefore, it is studied as HTL for perovskite solar cells in different device structures. Since device stability is the main concern of PSCs, NiO _x has good application prospects because of its excellent chemical stability that can improve device stability. However, Ni3 ⁺ species on the surface of _NiOx films are considered defects, which may lead to the attenuation of perovskite and the deterioration of hole transport dynamics at the _NiOx /perovskite interface. Therefore, it is difficult to improve the efficiency and stability of bare NiO _x- based PSCs. As another member of the iron family, cobalt has similar properties to nickel. Their oxide forms share similar p-type semiconductor properties, with _CoOx attracting widespread attention due to its high transmittance, suitable work function, and inherent stability. Currently, CoO _x HTL can be produced by sputtering, electrodeposition or pulsed laser deposition techniques. However, these methods are complex and expensive. Therefore, as a low-cost alternative method, CoO _x films are prepared as HTL using solution methods in the prior art. However, the solvents used in these preparation methods are organic solvents. The use of high-cost and toxic organic solvents will harm human health. , polluting the ecological environment. And the current device efficiency and stability of bare CoO _x- based PSCs still lag behind. The PCE of CoOx _- based PSCs reported in the literature varies significantly, ranging from less than 10% to more than 14.5%. This may be caused by the problem of low conductivity in cobalt oxide, which leads to increased recombination and reduced hole extraction. In addition, its electronic structure should be adjusted to better match the energy levels of the perovskite.

Contents of the invention

In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, a trans-perovskite solar cell with good conductivity and high stability is provided. The structure of the trans-perovskite solar cell is as follows: The top order is conductive glass, hole transport layer, perovskite absorption layer, electron transport layer, and electrode; the hole transport layer uses CoO _x as the hole transport material. In the hole transport layer, through lanthanum ions, CoO _x is doped with at least one metal ion selected from nickel ions, cesium ions, and magnesium ions.

Ni3 ⁺ defects on the surface of conventional nickel oxide ( _NiOx ) films may lead to perovskite attenuation and deterioration of hole transport dynamics at the _NiOx /perovskite interface. ^{The present invention} uses cobalt oxide _{( CoO} , therefore CoO _x will replace nickel oxide as the hole transport layer of perovskite solar cells with higher efficiency and stability. Combined with metal ion doping, the conductivity of CoO _x will be improved and better device performance will be obtained. .

In a second aspect of the present invention, a method for preparing a trans-perovskite solar cell that is simple to operate, low-cost, green and environmentally friendly is provided, including the following steps:

S1. Mix cobalt hydroxide and a dopant and dissolve it in water. Add a complexing agent and an emulsifier to the resulting solution, and then react at a certain temperature. After the reaction, collect the filtrate by filtration to obtain a CoO _x precursor solution. ;

S2. Remove impurities on the conductive glass surface to obtain a glass substrate;

S3. Coat the CoO _x precursor solution on the surface of the glass substrate, and undergo heat treatment to obtain a hole transport layer;

S4. Prepare and obtain a perovskite absorption layer on the surface of the hole transport layer;

S5. Dissolve the fullerene derivative in chlorobenzene to obtain a chlorobenzene solution of the fullerene derivative, apply it on the surface of the perovskite absorption layer, and undergo heat treatment to obtain an electron transport layer;

S6. Evaporate metal materials on the surface of the electron transport layer to form electrodes to obtain trans perovskite solar cells.

The present invention develops a simple and green method to obtain a solution-processed superior CoO _x hole transport layer, and provides a metal ion doping strategy for improving the conductivity of cobalt oxide. The optimized metal ion doped CoO _x hole transport layer has good conductivity and high device stability. The present invention uses CoO _x as a hole transport layer to obtain an efficient and stable perovskite solar cell, which has good application prospects.

Preferably, in step S1, the dopant is at least one of lanthanum nitrate, nickel nitrate, cesium acetate, and magnesium acetate.

Preferably, in step S1, the amount of the dopant added is 10% to 50% of the cobalt hydroxide in terms of molar percentage.

Preferably, in step S1, the complexing agent is at least one of ethylenediaminetetraacetic acid, dipotassium ethylenediaminetetraacetate, and disodium ethylenediaminetetraacetate.

Preferably, in step S1, the addition amount of the complexing agent is 50% to 80% of the cobalt hydroxide in terms of molar percentage.

Preferably, in step S1, the emulsifier is at least one of ethanolamine, formamide, and ethylene glycol.

Preferably, in the step S1, the relationship between the mass of the cobalt hydroxide and the volume of the emulsifier is 0.5 to 1.5 mg/μL.

Preferably, in step S1, the reaction temperature is 60-80°C, and the reaction time is 12-24 hours.

Preferably, in step S2, the conductive glass is an FTO glass substrate.

Preferably, in the step S3, the coating is performed by a spin coating method, the spin coating speed is 2000-4000 rpm, and the spin-coating time is 30-60 s.

Preferably, in step S3, the temperature of the heat treatment is 200-400°C, and the treatment time is 1-2 hours.

Preferably, in step S4, the material of the perovskite absorption layer is APbX ₃ perovskite crystal, wherein A is at least one of monovalent cesium ions, carboxamide ions, and formamidine ions, and X is iodine. ions or bromide ions.

Preferably, in step S5, the concentration of the fullerene derivative in the chlorobenzene solution of the fullerene derivative is 20 to 30 mg/mL.

Preferably, in step S5, the fullerene derivative is fullerene derivative PCBM.

Preferably, in the step S5, the coating is performed by a spin coating method, the spin coating speed is 2000-3000 rpm, and the spin coating time is 40-60 s.

Preferably, in step S5, the temperature of the heat treatment is 70-100°C, and the treatment time is 5-10 minutes.

Preferably, in step S6, the metal material of the electrode is silver or aluminum.

Compared with the existing technology, the present invention has the following advantages and beneficial effects:

The invention provides a trans perovskite solar cell, which uses CoO _x with high light transmittance, suitable work function and inherent stability as the hole transport material of the hole transport layer, which reduces the The attenuation of the absorber layer optimizes the hole transport dynamics at the interface, combined with metal ion doping, improves the conductivity of CoO _x and achieves better device performance, thus improving the efficiency and stability of trans perovskite solar cells. sex.

The invention provides a method for preparing a trans-perovskite solar cell, which is simple to operate, low in cost, green and environmentally friendly, and has good application prospects.

Description of the drawings

Figure 1 is a schematic structural diagram of a trans perovskite solar cell of the present invention. In the figure, 1 is conductive glass, 2 is a hole transport layer, 3 is a perovskite absorption layer, 4 is an electron transport layer, and 5 is an electrode;

Figure 2 is an X-ray diffraction (XRD) pattern of the hole transport layer of Example 3 and Comparative Example 1;

Figure 3 is a scanning electron microscope (SEM) image of the hole transport layer of Example 3 and Comparative Example 1;

Figure 4 is a graph of ultraviolet and visible light transmittance of the hole transport layer of Example 3 and Comparative Example 1;

Figure 5 is a J-V curve diagram of the batteries of Examples 1 to 4 and Comparative Example 1;

Figure 6 is a thermal stability graph of the batteries of Example 3 and Comparative Example 2.

Detailed ways

The present invention is further described below by means of examples, but the present invention is not limited to the scope of the described examples. Experimental methods that do not indicate specific conditions in the following examples should be selected according to conventional methods and conditions, or according to product specifications.

Example 1

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg cobalt hydroxide and magnesium acetate and dissolve it in 5 mL deionized water. Add ethylenediaminetetraacetic acid to the resulting solution, and finally add 25 μL ethanolamine. In terms of molar percentage, the amount of magnesium acetate added is cobalt hydroxide. 10% of ethylenediaminetetraacetic acid and 50% of cobalt hydroxide; then mix and react at 80°C for 24 hours. After the reaction is completed, cool to room temperature and filter with a 0.45 μm nylon filter to prepare a CoO _x precursor solution. ;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 4000 rpm. The coating time is 30 seconds. First, heat at 80°C for 5 minutes, and then anneal at 300°C for 1.5 hours for heat treatment. Obtain a hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a trans perovskite solar cell.

Example 2

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg cobalt hydroxide and magnesium acetate and dissolve it in 5 mL deionized water. Add ethylenediaminetetraacetic acid to the resulting solution, and finally add 25 μL ethanolamine. In terms of molar percentage, the amount of magnesium acetate added is cobalt hydroxide. 20% of ethylenediaminetetraacetic acid was added to 50% of cobalt hydroxide; then the mixture was reacted at 80°C for 24 hours. After the reaction was completed, it was cooled to room temperature and filtered with a 0.45 μm nylon filter to prepare a CoO _x precursor solution. ;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 4000 rpm. The coating time is 30 seconds. First, heat at 80°C for 5 minutes, and then anneal at 300°C for 1.5 hours for heat treatment. Obtain a hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a trans perovskite solar cell.

Example 3

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg cobalt hydroxide and magnesium acetate and dissolve it in 5 mL deionized water. Add ethylenediaminetetraacetic acid to the resulting solution, and finally add 25 μL ethanolamine. In terms of molar percentage, the amount of magnesium acetate added is cobalt hydroxide. 30% of ethylenediaminetetraacetic acid was added to 50% of cobalt hydroxide; then the mixture was reacted at 80°C for 24 hours. After the reaction was completed, it was cooled to room temperature and filtered with a 0.45 μm nylon filter to prepare a CoO _x precursor solution. ;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 4000 rpm. The coating time is 30 seconds. First, heat at 80°C for 5 minutes, and then anneal at 300°C for 1.5 hours for heat treatment. Obtain a hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a trans perovskite solar cell.

Example 4

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg cobalt hydroxide and magnesium acetate and dissolve it in 5 mL deionized water. Add ethylenediaminetetraacetic acid to the resulting solution, and finally add 25 μL ethanolamine. In terms of molar percentage, the amount of magnesium acetate added is cobalt hydroxide. 40% of ethylenediaminetetraacetic acid, and the added amount of ethylenediaminetetraacetic acid is 50% of cobalt hydroxide; then mix and react at 80°C for 24 hours. After the reaction is completed, cool to room temperature and filter with a 0.45 μm nylon filter to prepare a CoO _x precursor solution. ;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 4000 rpm. The coating time is 30 seconds. First, heat at 80°C for 5 minutes, and then anneal at 300°C for 1.5 hours for heat treatment. Obtain a hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a trans perovskite solar cell.

Example 5

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg of cobalt hydroxide and lanthanum nitrate and dissolve it in 5 mL of deionized water. Add dipotassium ethylenediaminetetraacetate to the resulting solution, and finally add 75 μL of formamide. In terms of mole percentage, the amount of lanthanum nitrate added is 50% of cobalt hydroxide, and the added amount of dipotassium ethylenediaminetetraacetate is 80% of cobalt hydroxide; then mix and react at 60°C for 12 hours, cool to room temperature after the reaction, and filter with a 0.45 μm nylon filter to prepare CoO _x precursor solution;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 2000 rpm. The coating time is 60 seconds. First, heat at 80°C for 5 minutes, and then anneal at 200°C for 2 hours for heat treatment. Obtain hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 20 mg/mL. Spin-coat it to cover the surface of the perovskite absorption layer at a spin-coating speed of 2000 rpm. /s, the spin coating time is 60s, and heated at 70°C for 10min to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Al electrode to obtain a trans perovskite solar cell.

Example 6

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg of cobalt hydroxide and nickel nitrate and dissolve it in 5 mL of deionized water. Add disodium ethylenediaminetetraacetate to the resulting solution, and finally add 25 μL of ethylene glycol. The amount of nickel nitrate added is based on molar percentage. It is 10% of cobalt hydroxide, and the added amount of disodium ethylenediaminetetraacetate is 50% of cobalt hydroxide; then mix and react at 80°C for 12 hours. After the reaction is completed, cool to room temperature and filter with a 0.45 μm nylon filter to prepare Obtain CoO _x precursor solution;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 2000 rpm. The coating time is 60 seconds. First, heat at 80°C for 5 minutes, and then anneal at 400°C for 1 hour for heat treatment. Obtain hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 30 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 2000 rpm. /s, the spin coating time is 60s, and heated at 100°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Al electrode to obtain a trans perovskite solar cell.

Example 7

Preparation method of trans perovskite solar cells:

S1. Mix 37.5 mg cobalt hydroxide and cesium acetate and dissolve it in 5 mL deionized water. Add ethylenediaminetetraacetic acid to the resulting solution, and finally add 25 μL ethanolamine. In terms of molar percentage, the added amount of cesium acetate is cobalt hydroxide. 10% of ethylenediaminetetraacetic acid and 50% of cobalt hydroxide; then mix and react at 80°C for 24 hours. After the reaction is completed, cool to room temperature and filter with a 0.45 μm nylon filter to prepare a CoO _x precursor solution. ;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 4000 rpm. The coating time is 30 seconds. First, heat at 80°C for 5 minutes, and then anneal at 300°C for 1.5 hours for heat treatment. Obtain a hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a trans perovskite solar cell.

Comparative example 1

Preparation method of trans perovskite solar cells:

S1. Dissolve 37.5mg cobalt hydroxide in 5mL deionized water, add ethylenediaminetetraacetic acid to the resulting solution, and finally add 25μL ethanolamine. In terms of molar percentage, the added amount of ethylenediaminetetraacetic acid is 50% of the cobalt hydroxide. %; then mix and react at 80°C for 24 hours. After the reaction is completed, cool to room temperature and filter with a 0.45 μm nylon filter to prepare a CoO _x precursor solution;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the CoO _x precursor solution to cover the surface of the glass substrate at a rotation speed of 4000 rpm. The coating time is 30 seconds. First, heat at 80°C for 5 minutes, and then anneal at 300°C for 1.5 hours for heat treatment. Obtain a hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction. The resulting perovskite film is heated in sequence. The plate is heated at 70°C for 1 minute, and then annealed at 120°C for 15 minutes to obtain the perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a trans perovskite solar cell.

Comparative example 2

Preparation method of solar cells:

S1. Dissolve 50 mmol nickel nitrate hexahydrate in 100 mL deionized water; then add 2.8 mL of 30% ammonia water to adjust the pH value of the solution to 8, and stir to obtain a precursor solution; then age it overnight and centrifuge at a speed of 5000 rpm/s Centrifuge the obtained solution for 5 minutes; wash the obtained precipitate twice with deionized water, and place the obtained precipitate in a vacuum drying oven to dry at 100°C for 12 hours; sinter the dried product at 270°C for 120 minutes to obtain a calcined product, which is calcined The product is nickel oxide nanoparticles; the obtained nickel oxide nanoparticles are dispersed into a mixed solvent of deionized water and isopropyl alcohol at a volume ratio of 3:1 at a concentration of 8 mg/mL to prepare a nickel oxide nanoparticle dispersion;

S2. The FTO glass substrate with a size of 1.5cm×1.3cm is sequentially ultrasonically cleaned and dried in ionized water, acetone, and ethanol to obtain a glass substrate;

S3. Spin-coat the nickel oxide nanoparticle dispersion liquid to cover the surface of the glass substrate, where the spin-coating speed is 4000 rpm and the spin-coating time is 40 s; then anneal on a hot plate at 150°C for 30 minutes to obtain oxidation Nickel nanoparticle hole transport layer;

S4. In a nitrogen atmosphere, dissolve lead iodide, formamidine iodide, and methylamine iodide in a mixed solvent of DMF and DMSO with a volume ratio of 4:1 to obtain a mixture. In the mixture, lead iodide, formamidine iodide, and The concentrations of , methylamine iodide and methylamine iodide are all 1.4mol/L; filter with a 0.2μm nylon filter to obtain FA _0.4 MA _0.6 PbI ₃ perovskite precursor liquid; add FA _0.4 MA _0.6 PbI ₃ perovskite at a rate of 5000 rpm. The precursor liquid is spin-coated to cover the surface of the hole transport layer of the nickel oxide nanoparticles. The total coating time is 30 seconds. In the last 11 seconds of the spin-coating process, 400 μL of ethyl acetate antisolvent is used for extraction, and the obtained perovskite is The film was heated on a hot plate at 70°C for 1 min, and then annealed at 120°C for 15 min to obtain a perovskite absorption layer;

S5. Dissolve the fullerene derivative PCBM in chlorobenzene in a nitrogen atmosphere to obtain a chlorobenzene solution of PCBM with a concentration of 25 mg/mL, and spin-coat it to cover the surface of the perovskite absorption layer. The spin-coating speed is 3000 rpm. /s, the spin coating time is 40s, and heated at 80°C for 5 minutes to obtain the electron transport layer;

S6. The surface of the electron transport layer is evaporated to form an Ag electrode to obtain a solar cell.

Test example 1

The structure of the trans perovskite solar cell of the present invention is shown in Figure 1. The crystal structures of the hole transport layers of Example 3 and Comparative Example 1 were characterized by X-ray diffraction (XRD), as shown in Figure 2. The diffraction peaks of Example 3 and Comparative Example 1 both show cubic crystal structures. At the same time, no additional diffraction peaks related to metallic Mg or magnesium oxide were observed, indicating that the doping of Mg hardly changes the phase structure of CoO _x . The micromorphology of the hole transport layer in Example 3 and Comparative Example 1 was observed with a scanning electron microscope (SEM). According to Figure 3, it can be seen that the hole transport layer has good flatness, and the surface is uniform and dense, which further illustrates the Mg-doped The impurity did not change its surface morphology.

The ultraviolet and visible light transmittance of the hole transport layer of Example 3 and Comparative Example 1 was tested. As shown in Figure 4, the hole transport layer of Comparative Example 1 has high optical transmittance and can reduce light absorption loss; Example The hole transport layer of 3 shows a slightly higher transmittance (>90%) than Comparative Example 1 in the ultraviolet-visible light region, and the light absorption loss is small.

The photovoltaic performance of the perovskite solar cells of some embodiments and comparative examples of the present invention was tested. The test was conducted under the conditions of AM1.5G standard solar spectrum and the effective area of the active layer was 0.06 cm ² . The test curve is shown in Figure 5, and the results are shown in Table 1.

Table 1:

As can be seen from the test results in Table 1, from the purpose of improving the photovoltaic efficiency of solar cells of the present invention, the efficiencies of Examples 1 to 4 are higher than that of the undoped solar cell in Comparative Example 1. Among Examples 1 to 4, Example 3 has the highest photovoltaic efficiency of 17.04%. Embodiment 3 is the best embodiment of the present invention. According to the test, when both ends are open circuit, the open circuit voltage of Embodiment 3 is 1.02V; the current density at zero voltage, that is, the short-circuit current density is 21.80mA/cm ² , theoretically The more photons absorbed on the surface, the greater the short-circuit current. When the effective area is constant, the corresponding short-circuit current density is also greater; the filling factor is the ratio of the maximum output power to the product of the open-circuit voltage and the short-circuit current. The filling factor of Example 3 is 0.77, the device interface has few defects.

Finally, the thermal stability of the solar cells of Example 3 and Comparative Example 2 was tested in an environment of 85° C. and a relative humidity of 30 to 40%. According to the test curve in Figure 6, it can be seen that Example 3 can retain 80% of the photoelectric conversion efficiency of the initial solar cell after continuous heating for 120 hours in the test environment; while the device of Comparative Example 2 is severely degraded, and the NiO _x- based solar cell of Comparative Example 2 is After heating for 90 hours under the same conditions, only 60% of the photoelectric conversion efficiency of the original solar cell can be retained. Obviously, Example 3 shows better thermal stability.

The preferred embodiments of the present invention are described in detail above. It should be understood that those skilled in the art can make many modifications and changes based on the concept of the present invention without creative efforts. Therefore, any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention and on the basis of the prior art should be within the scope of protection determined by the claims.

Claims (10)

1. A trans perovskite solar cell, characterized by: the structure of the trans-perovskite solar cell sequentially comprises conductive glass, a hole transport layer, a perovskite absorption layer, an electron transport layer and an electrode from bottom to top; the hole transport layer is formed by CoO _x As hole transport material and CoO by at least one metal ion selected from lanthanum ion, nickel ion, cesium ion, and magnesium ion _x Doping is performed.

2. A method of fabricating a trans perovskite solar cell as claimed in claim 1, comprising the steps of:

s1, mixing cobalt hydroxide and a doping agent, dissolving in water, adding a complexing agent and an emulsifying agent into the obtained solution, and then reacting at a certain temperature; filtering and collecting filtrate after the reaction is finished to obtain CoO _x A precursor solution;

s2, removing impurities on the surface of the conductive glass to obtain a glass substrate;

s3, coO is carried out _x Coating the precursor solution on the surface of a glass substrate, and performing heat treatment to obtain a hole transport layer;

s4, preparing and obtaining a perovskite absorption layer on the surface of the hole transport layer;

s5, dissolving the fullerene derivative in chlorobenzene to obtain a chlorobenzene solution of the fullerene derivative, coating the chlorobenzene solution on the surface of the perovskite absorption layer, and performing heat treatment to obtain an electron transport layer;

and S6, evaporating a metal material on the surface of the electron transport layer to form an electrode, thereby obtaining the trans-perovskite solar cell.

3. The method according to claim 2, characterized in that: in the step S1, the dopant is at least one of lanthanum nitrate, nickel nitrate, cesium acetate and magnesium acetate; the addition amount of the doping agent is 10-50% of the cobalt hydroxide by mole percent.

4. The method according to claim 2, characterized in that: in the step S1, the complexing agent is at least one of ethylenediamine tetraacetic acid, ethylenediamine tetraacetic acid dipotassium salt and ethylenediamine tetraacetic acid disodium salt; the addition amount of the complexing agent is 50-80% of that of the cobalt hydroxide in terms of mole percentage.

5. The method according to claim 2, characterized in that: the emulsifier is at least one of ethanolamine, formamide and ethylene glycol; the adding amount relation of the mass of the cobalt hydroxide and the volume of the emulsifier is 0.5-1.5 mg/mu L.

6. The method according to claim 2, characterized in that: in the step S1, the reaction temperature is 60-80 ℃ and the reaction time is 12-24 h.

7. The method according to claim 2, characterized in that: in the step S3, the coating is performed by adopting a spin coating method, the spin coating rotating speed is 2000-4000 rpm, and the spin coating time is 30-60S; the temperature of the heat treatment is 200-400 ℃ and the treatment time is 1-2 h.

8. The method according to claim 2, characterized in that: in the step S4, the perovskite absorption layer is made of APbX ₃ Perovskite crystal, wherein A is at least one of monovalent cesium ion, methylamine ion and formamidine ion, and X is iodine ion or bromine ion.

9. The method according to claim 2, characterized in that: in the step S5, the concentration of the fullerene derivative in the chlorobenzene solution of the fullerene derivative is 20-30 mg/mL; the fullerene derivative is a fullerene derivative PCBM.

10. The method according to claim 2, characterized in that: in the step S5, the coating is performed by adopting a spin coating method, the spin coating rotating speed is 2000-3000 rpm, and the spin coating time is 40-60S; the temperature of the heat treatment is 70-100 ℃ and the treatment time is 5-10 min.