Synergistic cerium ion doped perovskite solar cell and preparation method thereof

Abstract

The invention relates to a synergistic cerium ion doped perovskite solar cell and a preparation method thereof, Ce < 3 + > is doped in a SnO2 electron transport layer and a perovskite layer at the same time, a uniform and compact SnO2 film and a perovskite film are prepared, the defect density is reduced, and the energy conversion efficiency (PCE) of the FA-based perovskite solar cell is further improved. The efficiency of 21.5% is finally obtained, which is obviously improved compared with that of a Ce < 3 + >-doped SnO2 electron transport layer or a perovskite layer, and a new direction is provided for improving the PCE of the perovskite solar cell.

Description

Technical Field

[0001] The invention relates to a cerium ion-doped perovskite solar cell and a preparation method thereof, belonging to the technical field of perovskite solar cells. Background Art

[0002] Perovskite solar cells (PSCs) are a new type of solar cell that has developed rapidly. In the past decade or so, their power conversion efficiency (PCE) has been significantly improved. In recent years, they have received more and more attention and have great development potential. Among them, formamidinium-based perovskites have become the preferred material for preparing high-efficiency perovskite solar cells in recent years due to their suitable optical band gap and high thermal stability. However, perovskite solar cells still have the problem of low performance of the electron transport layer and the perovskite layer, which makes the battery unable to show high performance. Summary of the invention

[0003] The present invention provides a method for preparing a cerium ion-doped perovskite solar cell with simple process and low cost, and the energy conversion efficiency of the prepared perovskite solar cell is significantly improved.

[0004] This patent optimizes the SnO2 electron transport layer and the perovskite layer of the perovskite solar cell respectively, so that the cell shows higher performance. The invention proposes a method of simultaneously introducing Ce into the SnO2 electron transport layer and the perovskite layer. 3+ , a method to improve the energy conversion efficiency of perovskite solar cells.

[0005] A cerium ion-doped perovskite solar cell comprises: a conductive layer, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and an electrode stacked in sequence;

[0006] Wherein, cerium is doped in the electron transport layer; and / or cerium is doped in the perovskite light absorption layer.

[0007] The material of the conductive layer is one or more of FTO, ITO, ZnO, and In2O3.

[0008] The mass percentage of cerium in the electron transport layer is 1-5%, and the mass percentage of cerium in the perovskite light absorption layer is 0.05-1%.

[0009] The electron transport layer material is selected from SnO2, TiO2, ZnO or a mixture of one or more thereof.

[0010] The main material of the electron transport layer is SnO2.

[0011] The main material of the perovskite light absorption layer is FA 0.93 MA 0.04 Cs0.03 PbI 2.88 Br 0.12 .

[0012] The above-mentioned method for preparing a perovskite solar cell comprises the following steps:

[0013] Step 1, coating a conductive layer on the conductive glass;

[0014] Step 2, preparing a slurry of tin dioxide (SnO2), adding cerium salt therein, coating it on the conductive layer, and then heat treating it to obtain an electron transport layer;

[0015] Step 3, preparing a perovskite precursor solution, adding cerium salt therein, and coating it on the electron transport layer to obtain a perovskite light absorption layer;

[0016] Step 4, preparing a hole transport layer and an electrode on the perovskite light absorption layer in sequence to obtain a battery.

[0017] In the step 2, the slurry is prepared by tin dioxide and water in a weight ratio of 1:3-10, wherein the cerium salt is added in the form of an ethanol solution of CeCl3, and the volume ratio of the ethanol solution of CeCl3 to the slurry is 1-10μL:1mL; the concentration of the ethanol solution of CeCl3 is 0.05-0.3mol / L.

[0018] In the step 2, the heat treatment is carried out at 100-200° C. for 10-100 min.

[0019] In step 3, the perovskite precursor solution is obtained by dissolving 1-2M FAPbI3, 0.02-0.1M MAPbBr3, 0.02-0.1M sPbI3 and 0.1-1.0M MACl in 1mL of organic solvent, wherein the cerium salt is added in the form of a DMF solution of CeCl3, so that the concentration of CeCl3 in the perovskite precursor solution is 0.1-0.5wt%, and the concentration of the DMF solution of CeCl3 is 20-100μmol mL –1 .

[0020] The beneficial effects of the present invention are:

[0021] The synergistic cerium ion-doped perovskite solar cell of the present invention is achieved by simultaneously introducing Ce into the electron transport layer and the perovskite layer. 3+ The following effects are achieved: (1) Compared with single-doped Ce 3+In comparison, the battery obtained by the synergistic cerium ion doping strategy has a higher energy conversion efficiency. (2) The perovskite film obtained by the synergistic cerium ion doping strategy has better light absorption ability and lower carrier recombination. (3) The perovskite solar cell obtained by the synergistic cerium ion doping strategy has lower current leakage. (4) The pure electron transport battery obtained by the synergistic cerium ion doping strategy has a reduced defect density. (5) The perovskite solar cell obtained by the synergistic cerium ion doping strategy has higher external quantum efficiency and integrated current density within the light absorption range. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a SEM cross-sectional view of the perovskite solar cell provided by the present invention;

[0023] Figure 2 It is a JV curve diagram of the perovskite solar cell provided by Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention;

[0024] Figure 3 These are the absorption spectra of perovskite films of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention;

[0025] Figure 4 PL spectra of the perovskite films of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention;

[0026] Figure 5 It is a JV curve diagram of the perovskite solar cell provided in the dark state by Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention;

[0027] Figure 6 It is the JV curve of the battery with pure electron transmission provided by Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention in the dark state;

[0028] Figure 7 It is the EQE spectrum of the perovskite solar cell provided by Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention and the corresponding current density curve obtained by integration. DETAILED DESCRIPTION

[0029] Comparative Example 1 Preparation of FA-based perovskite solar cells

[0030] Step 1: Place FTO transparent conductive glass (1.2 cm × 1.5 cm) in deionized water, acetone, isopropanol, deionized water, and ethanol and ultrasonically clean for 30 min. Blow dry the FTO glass with nitrogen and use a plasma cleaner to clean the FTO glass for 5 min for the next step. The cleaning atmosphere is oxygen and the power is 100 W.

[0031] Step 2: Prepare a 0.15M n-butanol solution of di(acetylacetonato)diisopropyl titanate and stir it on a stirring table for 30 minutes to obtain a spin coating solution. Take 30μL of the spin coating solution and drop it on the FTO glass. Spin it at 3000rpm for 30s to obtain a thin film. Use a pointed cotton swab to dip a small amount of ethanol to wipe off one side of the film, then place the film on a heating table and heat it at 125℃ for 5min. Finally, place it in a muffle furnace and heat it at 500℃ for 30 minutes to obtain a c-TiO2 layer.

[0032] Step 3: Dilute the tin dioxide (SnO2) slurry with ultrapure water in a volume ratio of 1:6, and stir thoroughly to obtain a SnO2 precursor solution; place the FTO substrate in a UV ozone cleaner for 10 minutes and then place the substrate on a spreader; take 30 μL of SnO2 precursor solution and evenly spread it on the surface of the FTO conductive glass, start the spreader to rotate at high speed, and set the spreader parameters to a speed of 5000 rpm and a time of 30 seconds; then place it on a 150°C hot stage in an air environment for annealing for 30 minutes to obtain a SnO2 film; place the above-prepared SnO2 film in a UV ozone cleaner for 5 minutes for subsequent spin coating.

[0033] Step 4: First, FA needs to be prepared 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 The specific preparation method is as follows: 1.4M FAPbI3, 0.06M MAPbBr3, 0.045M CsPbI3 and 0.5M MACl were dissolved in 1mL DMF / DMSO (8:1v / v) solvent (excess 10% PbI2 was used to improve device performance), mechanically oscillated for 2h to clarify the solution, and FA was prepared. 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 Perovskite precursor. Filter the precursor solution with a 0.22 μm organic filter to remove possible undissolved salts. Spin-coat the perovskite precursor on FTO / c-TiO2 / SnO2 twice (1000 rpm, 5 s and 5000 rpm, 30 s). During the spin-coating process, chlorobenzene was added as an anti-solvent at 15 s. After the rotation stopped, anneal it on a heating table in the glove box at 120 ° C for 60 min.

[0034] Step 5: A Spiro-OMeTAD hole transport layer was deposited on top of the perovskite layer at 3500 rpm for 30 s. Its composition was 72.8 mg Spiro-OMeTAD, 18.8 μL of lithium bis(trifluoromethane)sulfonyl imide (Li-TFSI) stock solution (520 mg Li-TFSI in 1 mL acetonitrile), 28.8 μL tBP, and 1 mL chlorobenzene. Use a pointed sticky note to dip chlorobenzene and wipe off the film on one side that was previously reserved. The prepared film was placed in a desiccator for oxidation overnight.

[0035] Step 6: Use high vacuum evaporation equipment to evaporate, the electrode material used is Ag, and the evaporation speed is The film thickness is about 100nm, and the effective area of ​​the electrode is controlled by the mask plate and is 0.0625cm -2 .

[0036] Example 2Ce 3+ Preparation of doped perovskite layers

[0037] Compared with Example 1, the difference is that in step 4, CeCl3:DMF solution (50 μmol mL –1 ), so that the concentration of CeCl3 in the precursor solution is 0.2%.

[0038] Example 3Ce 3+ Preparation of doped SnO2 layer

[0039] Compared with Example 1, the difference is that in step 3, 3 μL of CeCl 3 :EtOH (0.1 mol / L) solution is added to 1 mL of SnO 2 aqueous solution.

[0040] Example 4 Preparation of PSCs doped with cerium ions

[0041] Compared with Example 1, the difference is that Ce is introduced simultaneously in step 3 and step 4. 3+ .

[0042] Characterization results

[0043] 1. SEM cross-section of perovskite solar cell

[0044] Figure 1 This is a SEM cross-sectional view of a perovskite solar cell. It can be seen that the prepared perovskite solar cell is mainly composed of a FTO substrate, c-TiO2 and SnO2 electron transport layers, FA 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 It consists of a perovskite layer, a Spiro-OMeTAD hole transport layer, and an Ag electrode.

[0045] 2. JV curve of perovskite solar cells

[0046] Figure 2 This is the JV curve of the perovskite solar cell. It can be seen that after the cerium ion doping, the PCE of the battery is significantly improved, and the PCE is 21.5%. The corresponding J sc 、V oc , FF are 24.8 mA cm -2 , 1.11V, 0.782.

[0047] 3. Absorption spectrum of perovskite film

[0048] Figure 3 This is the absorption spectrum of the perovskite film. It can be seen that after cerium ion doping, FA 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 The film has the strongest light absorption ability, which is because the perovskite film has better film quality and crystal size after synergistic optimization.

[0049] 4. PL spectrum of perovskite film

[0050] Figure 4 This is the PL spectrum of the perovskite film. The intensity of the PL emission peak is the lowest after synergistic cerium ion doping, indicating that the synergistic optimization reduces the defect density of the perovskite film and reduces non-radiative carrier recombination.

[0051] 5. JV curve of perovskite solar cell in dark state

[0052] Figure 5 The JV curve of the perovskite solar cell in the dark state. It can be seen that the coordinated cerium ion doping can reduce the current leakage, making the dark current density of the modified cell the lowest, indicating that the photogenerated carriers can be transmitted through the battery instead of being directly shunted.

[0053] 6. JV curve of a battery with pure electron transfer in the dark state

[0054] Figure 6 The JV curve of the perovskite solar cell in the dark state. The N defects To this end, a FTO / c-TiO2 / SnO2 / FA 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 / PC 61The JV curve of the BM / Ag battery with full electron transport in the dark was tested. TFL When , the current increases sharply, indicating that the trap state is filled. defects ) is calculated as:

[0055]

[0056] The initial battery voltage is V TFL 0.23V, Ce 3+ Doped FA 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 V of the rear battery TFL 0.21V, Ce 3+ V of the battery after SnO2 doping ETL TFL is 0.19V, and the V TFL is 0.17 V. It can be concluded that cooperative cerium ion doping can effectively reduce the defect density of the battery.

[0057] 7. EQE spectrum of perovskite solar cells and the corresponding integrated current density curve

[0058] Figure 7 The EQE spectrum of the perovskite solar cell and the corresponding integrated current density curve. After synergistic cerium ion doping, the EQE of the cell at 450-800nm ​​is improved. The short-circuit current density of the cell before and after the integrated synergistic optimization is 23.2 and 24.1 mA cm -2 , and J obtained by JV curve sc It remains basically consistent, which once again illustrates the reliability of the performance test data.

[0059] From the above experiments, it can be seen that the coordinated cerium ion doping strategy can significantly improve the quality of the SnO2 transport layer and perovskite film, reduce the defects of the film, inhibit the recombination of non-radiative carriers, and increase the PCE of the battery from the initial 19.2% to 21.5%.

Claims

1. A cerium ion-doped perovskite solar cell, comprising: a conductive layer, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and an electrode stacked in sequence; characterized in that: The electron transport layer is doped with cerium, and / or the perovskite light absorption layer is doped with cerium.

2. The synergistic cerium ion-doped perovskite solar cell according to claim 1, characterized in that: The material of the conductive layer is one or more of FTO, ITO, ZnO, and In2O3.

3. The synergistic cerium ion-doped perovskite solar cell according to claim 1, characterized in that: The mass percentage of cerium in the electron transport layer is 1-5%, and the mass percentage of cerium in the perovskite light absorption layer is 0.05-1%.

4. The synergistic cerium ion-doped perovskite solar cell according to claim 1, characterized in that: The electron transport layer material is selected from SnO2, TiO2, ZnO or a mixture of one or more thereof.

5. The synergistic cerium ion-doped perovskite solar cell according to claim 1, characterized in that: The main material of the electron transport layer is SnO2.

6. The synergistic cerium ion-doped perovskite solar cell according to claim 1, characterized in that: The main material of the perovskite light absorption layer is FA 0.93 MA 0.04 Cs 0.03 PbI 2.88 Br 0.12 .

7. The method for preparing a synergistic cerium ion-doped perovskite solar cell according to claim 1, characterized in that: The steps include: Step 1, coating a conductive layer on the conductive glass; Step 2, preparing a slurry of tin dioxide (SnO2), adding cerium salt therein, coating it on the conductive layer, and then heat treating it to obtain an electron transport layer; Step 3, preparing a perovskite precursor solution, adding cerium salt therein, and coating it on the electron transport layer to obtain a perovskite light absorption layer; Step 4, preparing a hole transport layer and an electrode on the perovskite light absorption layer in sequence to obtain a battery.

8. The preparation method according to claim 7, characterized in that: In the step 2, the slurry is prepared by tin dioxide and water in a weight ratio of 1:3-10, wherein the cerium salt is added in the form of an ethanol solution of CeCl3, and the volume ratio of the ethanol solution of CeCl3 to the slurry is 1-10μL:1mL; the concentration of the ethanol solution of CeCl3 is 0.05-0.3mol / L.

9. The preparation method according to claim 7, characterized in that: In the step 2, the heat treatment is carried out at 100-200° C. for 10-100 min.

10. The preparation method according to claim 7, characterized in that: In step 3, the perovskite precursor solution is obtained by dissolving 1-2M FAPbI3, 0.02-0.1M MAPbBr3, 0.02-0.1M CsPbI3 and 0.1-1.0M MACl in 1mL of organic solvent, wherein the cerium salt is added in the form of a DMF solution of CeCl3, so that the concentration of CeCl3 in the perovskite precursor solution is 0.1-0.5wt%, and the concentration of the DMF solution of CeCl3 is 20-100μmol mL –1 .

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