CN107482120A - A kind of perovskite battery based on composite electron transport layer and its preparation method - Google Patents

Abstract

The invention provides a kind of perovskite battery and preparation method based on NEW TYPE OF COMPOSITE electron transfer layer, it is related to perovskite area of solar cell.Perovskite battery of the present invention includes：Backing material, transparency electrode, electron transfer layer, perovskite light absorbing layer, hole transmission layer, to electrode.The metal composite oxide that wherein NEW TYPE OF COMPOSITE electron transfer layer is made up of the metallic element with different electronegativity, can be by changing different electronegative metals element ratios, adjust chemical state and the distribution of the energy level of electronic structure and electron transfer layer of element, reach and separate and collect the efficiency of light induced electron in perovskite with perovskite light absorbing layer more reasonably level-density parameter, raising.Preparation process of the present invention is easy and effective, positive effect, and the perovskite battery efficiency of preparation has application prospect from 15.10% lifting to 18.26%.

Description

A kind of perovskite battery based on composite electron transport layer and its preparation method

technical field

The invention relates to the field of perovskite solar cells, in particular to a perovskite cell based on a novel composite electron transport layer and a preparation method thereof.

Background technique

Due to the rapid economic development, the sharp increase in population, and the continuous advancement of industrialization, energy shortage and environmental pollution have become two major problems facing mankind today. The rapid development of clean energy and renewable energy is currently the main solution. Solar cells convert light energy into electrical energy, are clean and pollution-free, and have very broad application prospects. Perovskite solar cells are a type of solar cells that are rapidly developing at present, with the characteristics of high efficiency, low cost, and simple preparation. After several years of rapid development, it has rapidly increased from 3.8% in 2009 to 22.1%.

According to the structure, perovskite solar cells are divided into planar structure and mesoporous structure, mainly including transparent electrode, electron transport layer, perovskite light-absorbing material, hole transport layer, counter electrode, etc. After the perovskite material absorbs light, photogenerated electrons and holes are generated, which are transmitted to the electron transport layer and the hole transport layer respectively, and are connected with the external circuit to form a loop to output electric energy. At present, the main electron transport layer materials are mainly metal oxide semiconductors with high chemical stability, but due to their characteristics such as low carrier mobility, high defect concentration, and energy level mismatch, it seriously restricts the photogenerated electrons from perovskite to light. The absorption layer is transferred to the electron transport layer, causing problems such as low device efficiency, inconsistent forward and reverse scanning, and unstable performance.

Therefore, it is extremely important to improve the ability of the metal oxide electron transport layer to separate and extract photogenerated carriers, reduce the recombination of interfacial defects, and optimize the energy level matching between the electron transport layer and the perovskite active layer.

Contents of the invention

Aiming at the problems of defect and energy level mismatch in the transfer of photogenerated electrons from perovskite solar cells from the perovskite light absorbing layer to the electron transport layer, the present invention proposes to compound different electronegative metal elements in the electron transport layer to change the element Chemical state and electronic structure, which in turn cause changes in the energy level distribution of the electron transport layer to achieve an energy level arrangement that is more compatible with perovskite light absorption, so as to improve the efficiency of carrier separation and collection and reduce interface recombination, thereby improving the performance of perovskite solar cells. photovoltaic performance.

In order to realize the purpose of the present invention, concrete technical scheme is as follows:

The present invention is based on a perovskite battery with a composite electron transport layer, and its battery structure includes a substrate material, a transparent electrode, an electron transport layer, a perovskite light absorption layer, a hole transport layer and a counter electrode from bottom to top, wherein the electron transport The layer is a planar structure or a porous skeleton structure.

The substrate material is hard transparent glass or flexible organic plastic.

The transparent electrode has the ability to collect and transport electrons, is indium tin oxide, fluorine tin oxide or aluminum zinc oxide, has a light transmittance of >70%, and a surface resistance of <15Ω.

The electron transport layer has the function of separating and transporting the photogenerated electrons in the perovskite material to the transparent electrode, and is mainly composed of metal oxides, in which two or more metal elements are combined and have different electronegativity; the porous skeleton It is a microporous interpenetrating structure, the particle size of metal particles is 10-50nm, and the thickness is 80-600nm.

The perovskite light absorbing layer material is ABX ₃ type, wherein A can be Rb ⁺ , Cs ⁺ , CH ₃ NH ₃ ⁺ , HC(NH ₂ ) ₂ ⁺ , B can be Pb, Sn, Cu, and X can be Cl, Br, I, SCN, etc.; the perovskite light absorption layer can form a planar heterojunction with the planar electron transport layer; or infiltrate and fill the porous structure electron transport layer, and form a dense and uniform layer of perovskite on the porous skeleton Thin film; the thickness of the perovskite film is 100-1000nm.

The hole transport layer is one or more of Spiro-OMeTAD, P3HT, PTAA, CuI, CuSCN, Cu ₂ O, NiOx and MoOx.

The counter electrode is an opaque or translucent metal electrode or a conductive carbon material electrode.

The preparation method of above-mentioned perovskite solar cell comprises the following steps:

(1) Configure (FAPbI ₃ ) _x (MAPbBr ₃ ) _1-x perovskite precursor solution dissolved in polar solvent; configure acidic titanium isopropoxide solution dissolved in isopropanol as a dense titanium dioxide precursor solution ;

(2) Preparation of metal salt solution: Dissolve high-purity anhydrous grade yttrium chloride (YCl ₃ ) metal salt powder in anhydrous ethanol solution, and configure solutions with different concentrations of 0-20 mg/ml;

(3) Deposition of composite electronegative metal oxide electron transport layer: spin-coat the dense TiO ₂ precursor solution prepared in step (1) on the surface of FTO, bake at 100-150°C for 5-20min, and put it into the muffle furnace. Then sinter at 450-550°C for 30-90min to obtain a 10-100nm dense TiO ₂ electron transport layer with good electrical properties; mix commercial Dyesol 30-NRD with ethanol, spin-coat and bake at 100-150°C for 5 -20min, then put it into a muffle furnace and sinter at 450-550°C for 30-90min to form interpenetrating micropores. By adjusting the mixing ratio of Dyesol 30-NRD and ethanol, the thickness of the porous layer is controlled to be 80-600nm; Put it into other electronegative metal salt (yttrium chloride) solution and let it stand for treatment, take it out, blow dry the solution, and sinter in a muffle furnace at 450-550°C for 30-90min;

(4) Preparation of the perovskite light-absorbing layer by solution method: drop the perovskite precursor on the surface of the electron transport layer, add a non-polar solvent to extract the polar solvent during the spin coating process, and then bake at 60-150 °C Dry annealing for 5-60 minutes to crystallize; by adjusting the concentration of the precursor and the spin coating speed, the thickness of the perovskite light-absorbing layer is controlled to 100-1000nm, and a heterojunction is formed with the electron-transport layer of the composite electronegative metal oxide. The electron-transport layer contains Two or more metal elements with different electronegativity;

(5) Hole transport layer deposition: Spin-coat the hole transport layer on the surface of the perovskite light-absorbing layer, and control the thickness to 100-400nm by controlling the solution concentration and rotational speed;

(6) Deposition of the counter electrode: the gold electrode is deposited by the thermal evaporation method, and the thickness is controlled to be 50-150nm.

The solvent of the solution method described in step (4) includes polar solvents and non-polar solvents, wherein polar solvents dissolve perovskite materials, including dimethylformamide, dimethyl sulfoxide, gamma-butyrolactone One or more; non-polar solvents are mutually insoluble with perovskite materials, including benzene, toluene, 1,2-xylene, 1,3-xylene, 1,4-xylene, chlorobenzene, 1,2 -One or more of dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, ethanol, isopropanol.

The feature of the present invention is that the novel composite electron transport layer is a composite metal oxide composed of metal elements with different electronegativity, and the chemical state, electronic structure and electron transport of the element can be adjusted by changing the ratio of metal elements with different electronegativity. The energy level distribution of the perovskite layer can achieve a more reasonable energy level match with the perovskite light absorption layer, reduce the recombination of photogenerated electrons and holes at the interface, improve the efficiency of separating and collecting photogenerated electrons in perovskite, effectively increase the short-circuit current, and ultimately improve the device performance. The preparation process of the invention is simple and effective, and the effect is obvious, and the efficiency of the prepared perovskite battery is increased from 15.10% to 18.26%, which has application prospects.

Description of drawings

Figure 1 is a comparison of the photoelectric properties of Example 1 and Comparative Example 1.

Fig. 2 is the X-ray photoelectron spectrum of the electron transport layer of Example 1 and Comparative Example 1.

FIG. 3 is the time-resolved fluorescence spectra of Example 1 and Comparative Example 1.

detailed description

Below in conjunction with embodiment, the present invention is further described in detail. It is to those skilled in the art that the present invention can be fully understood without these detailed descriptions. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1:

Construction of perovskite solar cells with composite electronegative metal oxide electron transport layers

(1) Configuration (FAPbI ₃ ) _0.83 (MAPbBr ₃ ) _0.17 precursor: PbI ₂ concentration is 1.1M, FAI concentration is 1M, PbBr concentration is 0.22M, MABr concentration is 0.2M, solvent is dimethylformamide (DMF ) and dimethyl sulfoxide (DMSO), wherein the solvent volume ratio is 4:1; configure a dense titanium dioxide precursor: a mixed isopropanol solution with a concentration of 0.23M titanium isopropoxide and 0.013M hydrochloric acid;

(2) Preparation of yttrium chloride ethanol solution: high _- purity anhydrous grade YCl3 powder is dissolved in anhydrous grade ethanol solution, and the configuration concentration is 2mg/ml solution;

(3) FTO conductive glass is used as the substrate and transparent electrode, the light transmittance is 80%, and the surface resistance is 15Ω;

(4) Deposition of composite electronegative metal oxide electron transport layer: Spin-coat the dense TiO ₂ precursor liquid prepared in step (1) on the surface of FTO, bake at 125°C for 5min, put it into a muffle furnace for sintering at 500°C for 30min, A 30nm dense _TiO2 electron transport layer with good electrical properties was obtained; commercial Dyesol 30-NRD was mixed with ethanol in proportion, after spin coating, it was baked at 125°C for 5min, and then put into a muffle furnace for sintering at 500°C for 30min , forming interpenetrating micropores with a thickness of 200nm; then put it into the yttrium chloride ethanol solution for static treatment, take it out, blow dry the solution, and sinter in a muffle furnace at 500°C for 30min;

(5) Preparation of the perovskite light-absorbing layer by solution method: drop the perovskite precursor on the surface of the electron transport layer, quickly drop chlorobenzene as a non-polar solvent during the spin coating process to extract the polar solvent, and then heat Dry and anneal at 100°C on the stage for 30 minutes to crystallize, with a thickness of 500nm;

(6) Hole transport layer deposition: Spiro-OMeTAD solution dissolved in chlorobenzene was spin-coated on the surface of the perovskite light-absorbing layer, and the thickness was controlled to be 200nm;

(7) Counter electrode deposition: A gold electrode is deposited by a thermal evaporation method with a thickness of 80 nm.

Comparative example 1:

Perovskite solar cells with a single electronegative metal oxide electron transport layer and its preparation

(1) Configuration (FAPbI ₃ ) _0.83 (MAPbBr ₃ ) _0.17 precursor: PbI ₂ concentration is 1.1M, FAI concentration is 1M, PbBr concentration is 0.22M, MABr concentration is 0.2M, solvent is dimethylformamide (DMF ) and dimethyl sulfoxide (DMSO), wherein the solvent volume ratio is 4:1; configure a dense titanium dioxide precursor: a mixed isopropanol solution with a concentration of 0.23M titanium isopropoxide and 0.013M hydrochloric acid;

(2) FTO conductive glass is used as the substrate and transparent electrode, the light transmittance is 80%, and the surface resistance is 15Ω;

(3) Deposition of a single electronegative metal oxide electron transport layer: spin-coat the dense TiO ₂ precursor liquid prepared in step (1) on the surface of FTO, bake at 125°C for 5min, put it into a muffle furnace for sintering at 500°C for 30min, Obtain a 30nm dense _TiO2 electron transport layer with good electrical properties; mix commercial Dyesol 30-NRD with ethanol in proportion, spin-coat and bake at 125°C for 5min, then put it in a muffle furnace and sinter at 500°C for 30min , forming interpenetrating micropores with a thickness of 200nm;

(4) Preparation of the perovskite light-absorbing layer by solution method: drop the perovskite precursor on the surface of the electron transport layer, quickly drop chlorobenzene as a non-polar solvent to extract the polar solvent during the spin coating process, and then heat Dry and anneal at 100°C on the stage for 30 minutes to crystallize, with a thickness of 500nm;

(5) Hole transport layer deposition: Spiro-OMeTAD solution dissolved in chlorobenzene was spin-coated on the surface of the perovskite light-absorbing layer, and the thickness was controlled to be 200nm;

(6) Counter electrode deposition: A gold electrode is deposited by thermal evaporation method, with a thickness of 80 nm.

Device performance test

The solar cells of Example 1 and Comparative Example 1 were tested under standard light intensity (Newport, AM 1.5G, 100 mW cm ⁻² ). The measurement results are shown in Figure 1. Using the composite electronegative metal oxide as the electron transport layer, the efficiency of the perovskite battery is greatly improved to 18.26%. The specific battery performance parameters are shown in Table 1.

Table 1 Performance parameters of perovskite cells

Figure 2 shows the X-ray photoelectron spectrum of the electron transport layer. By comparison, it can be found that Y 3d5 and Y 3d3 appear at 157.3eV and 159.3eV, indicating that the yttrium element in the composite electronegative metal oxide electron transport layer is successfully deposited onto the surface of _TiO2 .

Figure 3 shows the time-resolved fluorescence spectra, the results show that the lifetime of the photogenerated carriers on the composite electronegative metal oxide electron transport layer is shorter, indicating that the composite electronegative metal oxide electron transport layer has stronger electron separation and collection ability, reducing interfacial recombination, increasing short-circuit current, and finally improving the photoelectric performance of the device.

Example 2:

Construction of perovskite solar cells with planar composite electronegative metal oxide electron transport layers

(1) Configuration (FAPbI ₃ ) _0.83 (MAPbBr ₃ ) _0.17 precursor: PbI ₂ concentration is 1.1M, FAI concentration is 1M, PbBr concentration is 0.22M, MABr concentration is 0.2M, solvent is dimethylformamide (DMF ) and dimethyl sulfoxide (DMSO), wherein the solvent volume ratio is 4:1; configure a dense titanium dioxide precursor: a mixed isopropanol solution with a concentration of 0.23M titanium isopropoxide and 0.013M hydrochloric acid;

(2) Preparation of yttrium chloride ethanol solution: high _- purity anhydrous grade YCl3 powder is dissolved in anhydrous grade ethanol solution, and the configuration concentration is 2mg/ml solution;

(3) FTO conductive glass is used as the substrate and transparent electrode, the light transmittance is 80%, and the surface resistance is 15Ω;

(4) Deposition of planar composite electronegative metal oxide electron transport layer: Spin-coat the dense TiO ₂ precursor liquid prepared in step (1) on the surface of FTO, bake at 125°C for 5min, put it into a muffle furnace for sintering at 500°C 30min, to obtain a 30nm dense _TiO2 electron transport layer with good electrical properties; then put it in the yttrium chloride ethanol solution for static treatment, take it out, dry the solution, and sinter in a muffle furnace at 500°C for 30min;

(5) Preparation of the perovskite light-absorbing layer by solution method: drop the perovskite precursor on the surface of the electron transport layer, quickly drop chlorobenzene as a non-polar solvent during the spin coating process to extract the polar solvent, and then heat Dry and anneal at 100°C on the stage for 30 minutes to crystallize, with a thickness of 500nm;

(6) Hole transport layer deposition: Spiro-OMeTAD solution dissolved in chlorobenzene was spin-coated on the surface of the perovskite light-absorbing layer, and the thickness was controlled to be 200nm;

(7) Counter electrode deposition: A gold electrode is deposited by a thermal evaporation method with a thickness of 80 nm.

Example 3:

Construction of methylamine-lead-iodide perovskite solar cells with composite electronegative metal oxide electron transport layer

(1) Configure the MAPbI ₃ precursor: the concentration of PbI ₂ is 1.143M, the concentration of MAI is 1.43M, the solvent is dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and the solvent volume ratio is 9:1 ; Configure a dense titanium dioxide precursor: a mixed isopropanol solution with a concentration of 0.23M titanium isopropoxide and 0.013M hydrochloric acid;

(2) Preparation of yttrium chloride ethanol solution: high _- purity anhydrous grade YCl3 powder is dissolved in anhydrous grade ethanol solution, and the configuration concentration is 2mg/ml solution;

(3) FTO conductive glass is used as the substrate and transparent electrode, the light transmittance is 80%, and the surface resistance is 15Ω;

(4) Deposition of composite electronegative metal oxide electron transport layer: Spin-coat the dense TiO ₂ precursor liquid prepared in step (1) on the surface of FTO, bake at 125°C for 5min, put it into a muffle furnace for sintering at 500°C for 30min, A 30nm dense _TiO2 electron transport layer with good electrical properties was obtained; commercial Dyesol 30-NRD was mixed with ethanol in proportion, after spin coating, it was baked at 125°C for 5min, and then put into a muffle furnace for sintering at 500°C for 30min , forming interpenetrating micropores with a thickness of 200nm; then put it into the yttrium chloride ethanol solution for static treatment, take it out, blow dry the solution, and sinter in a muffle furnace at 500°C for 30min;

(5) Preparation of methylamine lead iodide perovskite light-absorbing layer by solution method: drop perovskite precursor on the surface of electron transport layer, and quickly drop chlorobenzene as a non-polar solvent to extract polar solvent during spin coating , and then dried and annealed on a hot stage at 100°C for 30 minutes to crystallize, with a thickness of 500nm;

(6) Hole transport layer deposition: Spiro-OMeTAD solution dissolved in chlorobenzene was spin-coated on the surface of the perovskite light-absorbing layer, and the thickness was controlled to be 200nm;

(7) Counter electrode deposition: A gold electrode is deposited by a thermal evaporation method with a thickness of 80 nm.

The above examples describe in detail a perovskite battery based on a novel electron transport layer and its preparation method provided by the present invention. The composite electronegative metal oxide electron transport layer improves the separation and collection efficiency of carriers, reduces the recombination of photogenerated electrons and holes at the interface, effectively increases the short-circuit current, and finally improves the performance of the device.

The above description is only an example of the invention. It should be pointed out that for those skilled in the art, without departing from the spirit and scope of the present invention, any modification or deformation of the device structure disclosed in the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (9)

1. A perovskite battery based on a composite electron transport layer, characterized in that the battery structure comprises a substrate material, a transparent electrode, an electron transport layer, a perovskite light absorbing layer, a hole transport layer and a pair of The electrode, wherein the electron transport layer is a planar structure or a porous skeleton structure. 2. The perovskite battery according to claim 1, wherein the substrate material is hard transparent glass or flexible organic plastic. 3. The perovskite battery according to claim 1, wherein the transparent electrode has the ability to collect and transport electrons, and is any one of indium tin oxide, fluorine tin oxide or aluminum zinc oxide, Transmittance>70%, surface resistance<15Ω. 4. The perovskite battery as claimed in claim 1, wherein the electron transport layer is composed of metal oxides, wherein metal elements are two or more combinations with different electronegativity; the electron transport layer The porous framework of the layer is a microporous interpenetrating structure, the particle size of the metal particles is 10-50 nm, and the thickness is 80-600 nm. 5. The perovskite cell according to claim 1, wherein the perovskite light absorbing layer material is ABX ₃ type, wherein A is Rb ⁺ , Cs ⁺ , CH ₃ NH ₃ ⁺ , HC(NH ₂ ) ₂ ⁺ , B is Pb, Sn, Cu, X is Cl, Br, I, SCN, etc.; the perovskite light absorbing layer can form a planar heterojunction with the planar electron transport layer; or infiltrate and fill the porous structure electron transport layer , and form a dense and uniform perovskite film on the porous skeleton; the thickness of the perovskite film is 100-1000 nm. 6. The perovskite battery according to claim 1, wherein the hole transport layer is one of Spiro-OMeTAD, P3HT, PTAA, CuI, CuSCN, Cu ₂ O, NiOx and MoOx or Various. 7. The perovskite battery according to claim 1, wherein the counter electrode is an opaque or translucent gold or silver electrode or a conductive carbon material electrode. 8. The preparation method of the perovskite battery described in any one of claims 1-7, is characterized in that, comprises the following steps: 1) Prepare (FAPbI ₃ ) _x (MAPbBr ₃ ) _1-x perovskite precursor solution dissolved in polar solvent; prepare acidic titanium isopropoxide solution dissolved in isopropanol as a dense titanium dioxide precursor solution; 2) Preparation of metal salt solution: Dissolve high-purity anhydrous yttrium chloride powder in anhydrous ethanol solution, and prepare solutions with different concentrations of 0-20mg/ml; 3) Deposition of composite electronegative metal oxide electron transport layer: Spin-coat the dense TiO ₂ precursor liquid prepared in step 1) on the surface of the transparent electrode, bake it at 100-150 ^o C for 5-20 min, and put it into the muffle furnace , and then sintered at 450~550 ^o C for 30-90 min to obtain a dense TiO ₂ electron transport layer of 10-100 nm; mixed commercial Dyesol 30-NRD with ethanol, and baked at 100-150 ^o C after spin coating for 5 -20 min, then put it into a muffle furnace and sinter at 450~550 ^o C for 30-90 min to form interpenetrating micropores. By adjusting the mixing ratio of Dyesol 30-NRD and ethanol, the thickness of the porous layer is controlled to be 80-600 nm ; Then put it into other electronegative yttrium chloride solution and let it stand for processing, take it out, blow dry the solution, and sinter in a muffle furnace at 450~550 ^o C for 30-90 min; 4) Preparation of the perovskite light-absorbing layer by solution method: drop the perovskite precursor on the surface of the electron transport layer, add a non-polar solvent to extract the polar solvent during the spin coating process, and then bake at 60-150 ^o C Dry annealing for 5-60 min to crystallize; control the thickness of the perovskite light-absorbing layer to 100-1000 nm by adjusting the concentration of the precursor and the spin-coating speed; 5) Hole transport layer deposition: Spin-coat the hole transport layer solution on the surface of the perovskite light-absorbing layer, and control the thickness to 100-400 nm by controlling the solution concentration and rotation speed; 6) Deposition of the counter electrode: the gold electrode is deposited by the thermal evaporation method, and the thickness is controlled to be 50-150 nm. 9. The preparation method of perovskite battery as claimed in claim 8, the solvent of the solution method described in step 4) includes a polar solvent and a non-polar solvent, wherein the polar solvent dissolves the perovskite material, including dimethyl One or more of phenyl formamide, dimethyl sulfoxide, and γ-butyrolactone; non-polar solvents are mutually insoluble with perovskite materials, including benzene, toluene, 1,2-xylene, 1,3- One or more of xylene, 1,4-xylene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, ethanol, isopropanol.