METHOD FOR PREPARING INORGANIC PEROVSKITE BATTERY BASED ON SYNERGISTIC EFFECT OF GRADIENT ANNEALING AND ANTISOLVENT, AND PREPARED INORGANIC PEROVSKITE BATTERY

Abstract

A method for preparing an inorganic perovskite battery based on a synergistic effect of gradient annealing and antisolvent includes preparing a perovskite layer by a gradient annealing and an antisolvent treatment. A thickness of the perovskite layer is 100 to 1000 nm; when preparing a perovskite precursor solution of the perovskite layer, a solvent is an amide-based solvent and/or a sulfone-based solvent; a concentration of the perovskite precursor solution for preparing the perovskite layer is 0.4 to 2 M; and the gradient annealing is conducted at 40 to 70° C./0.5 to 5 min+70 to 130° C./0.5 to 5 min+130 to 160° C./5 to 20 min+160 to 280° C./0 to 20 min; and a solvent for the anti-solvent treatment is an alcohol solvent, a benzene solvent or an ether solvent.

Claims

1. A method for preparing an inorganic perovskite battery based on a synergistic effect of gradient annealing and antisolvent, comprising preparing a perovskite layer by a gradient annealing and an antisolvent treatment.

2. The method for preparing an inorganic perovskite battery based on the synergistic effect of gradient annealing and antisolvent according to claim 1, wherein a thickness of the perovskite layer is 100 to 1000 nm; when preparing a perovskite precursor solution of the perovskite layer, a solvent is an amide-based solvent and/or a sulfone-based solvent; a concentration of the perovskite precursor solution for preparing the perovskite layer is 0.4 to 2 M; and the gradient annealing is conducted at 40 to 70° C./0.5 to 5 min+70 to 130° C./0.5 to 5 min+130 to 160° C./5 to 20 min+160 to 280° C./0 to 20 min; a solvent for the anti-solvent treatment is an alcohol solvent, a benzene solvent or an ether solvent.

3. The method for preparing an inorganic perovskite battery based on the synergistic effect of gradient annealing and antisolvent according to claim 1, wherein the perovskite layer is an all-inorganic CsPbXSn.sub.1-XIyBr.sub.3-y, where 0≤y≤3, 0≤x≤1; or Cs.sub.aK.sub.bRb.sub.1-a-bPb.sub.cSndCa.sub.eMg.sub.1-c-d-eIyBr.sub.3-y, where 0≤a≤1, 0≤b≤1, 0≤c≤1, 0≤d≤1, 0≤e≤1, a+b=1, c+d+e=1, 0≤y≤3; or CuInGaSn, CsAgBiI (Br), Cs.sub.xFAyMA.sub.1-x-yPbIzBr.sub.3-z, where 0≤x≤1, 0≤y≤1, x+y≤1, 0≤z≤3.

4. The method for preparing an inorganic perovskite battery based on the synergistic effect of gradient annealing and antisolvent according to claim 1, comprising the following steps: (1) preparing a cathode on a transparent substrate; (2) preparing an electron transport layer on the cathode; (3) preparing the perovskite layer on the electron transport layer by the gradient annealing and the anti-solvent treatment; (4) preparing a hole transporting layer on the perovskite layer; (5) preparing an electrode on the hole transport layer to obtain a perovskite solar cell; or (1) preparing an anode on the transparent substrate; (2) preparing a hole transport layer on the anode; (3) preparing the perovskite layer on the hole transport layer by the gradient annealing and the anti-solvent treatment; (4) preparing an electron transport layer on the perovskite layer; (5) preparing an electrode on the electron transport layer to obtain a perovskite solar cell.

5. A method for preparing a perovskite thin film for an inorganic perovskite battery, comprising the following steps: (1) preparing a cathode on a transparent substrate; (2) preparing an electron transport layer on the cathode; (3) preparing the perovskite thin film on the electron transport layer by a gradient annealing and an antisolvent treatment; or (1) preparing an anode on the transparent substrate; (2) preparing a hole transport layer on the anode; (3) preparing the perovskite thin film on the hole transport layer by the gradient annealing and the antisolvent treatment.

6. The method according to claim 4, wherein the transparent substrate is a glass substrate, a quartz substrate, a PET plastic substrate, a PEN plastic substrate, or a flexible grid silver substrate; the cathode is indium tin oxide or fluorine-doped tin dioxide; the anode is indium tin oxide or fluorine-doped tin dioxide; the electron transport layer is ZnO, TiO.sub.2, SnO.sub.2, PCBM, fullerene, or a fullerene derivative; the hole transport layer is selected from the group consisting of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly3,4-ethylenedioxythiophene/polystyrene sulfonate, nickel oxide, copper oxide, 2,2′,7,7′-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9′-spirobi-fluorene, cuprous thiocyanate, and molybdenum oxide.

7. The method according to claim 4, wherein the electrode is one or more selected from the group consisting of an Au electrode, an Ag electrode, an Al electrode, a cu electrode, a carbon electrode, a PH1000 polymer electrode, and a metal oxide electrode.

8. An inorganic perovskite battery prepared according to the method of claim 1.

9. A perovskite thin film for an inorganic perovskite battery prepared according to the method of claim 5.

10. (canceled)

11. The method according to claim 5, wherein the transparent substrate is a glass substrate, a quartz substrate, a PET plastic substrate, a PEN plastic substrate, or a flexible grid silver substrate; the cathode is indium tin oxide or fluorine-doped tin dioxide; the anode is indium tin oxide or fluorine-doped tin dioxide; the electron transport layer is ZnO, TiO.sub.2, SnO.sub.2, PCBM, fullerene, or a fullerene derivative; the hole transport layer is selected from the group consisting of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly3,4-ethylenedioxythiophene/polystyrene sulfonate, nickel oxide, copper oxide, 2,2′,7,7′-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9′-spirobi-fluorene, cuprous thiocyanate, and molybdenum oxide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 is a photo of direct high temperature annealing and gradient annealing of CsPbI.sub.2Br in Example 1;

[0048] FIG. 2 is a SEM image of CsPbI.sub.2Br direct high temperature annealing and gradient annealing in Example 1;

[0049] FIG. 3 is a SEM cross-sectional view of a CsPbI.sub.2Br perovskite layer in Example 1, which is Glass/ITO/TiO.sub.2/CsPbI.sub.2Br/Spiro-OMeTAD/Au from bottom to top;

[0050] FIG. 4 is a J-V curve diagram of direct high temperature annealing and gradient annealing of a CsPbI.sub.2Br perovskite battery in Example 1;

[0051] FIG. 5 is a SEM image of a high temperature annealing of a CsPbI.sub.2Br perovskite film in Example 2 after isopropanol treatment;

[0052] FIG. 6 is a color change diagram of gradient annealing of a CsPbI.sub.2Br perovskite layer in Example 2 after different antisolvent treatments;

[0053] FIG. 7 is a SEM image of a CsPbI.sub.2Br film treated with different antisolvents in Example 2 after being annealed at 50° C. for 1 minute;

[0054] FIG. 8 is a comparison of an optical microscope image and a SEM image of a fringe CsPbI.sub.2Br perovskite thin film edge and a center in Example 2;

[0055] FIG. 9 is a photograph of specular reflection of a CsPbI.sub.2Br film treated with diisopropanol in Example 2;

[0056] FIG. 10 is a SEM image of a CsPbI.sub.2Br film treated with different antisolvents in Example 2;

[0057] FIG. 11 is a J-V curve diagram of a CsPbI.sub.2Br device treated with different anti-solvents in Example 2;

[0058] FIG. 12 is a simulation diagram of the synergistic effect of gradient annealing and antisolvent in Example 2;

[0059] FIG. 13 shows the humidity stability of the CsPbI.sub.2Br device under the synergistic effect of gradient annealing and antisolvent in Example 2.

EMBODIMENTS OF THE INVENTION

[0060] The present invention will be described in detail with reference to the following embodiments:

Example 1

[0061] (1) A rigid substrate of glass was used for polishing, and then a layer of indium tin oxide film was plated on the glass by a magnetron sputtering method to form an ITO conductive glass as a cathode of a solar cell;

[0062] (2) Spin-coating TiO.sub.2 solution on ITO conductive glass, 3000 rpm 30 s, and then annealed at 150° C. for 30 min to obtain an electron transport layer with a thickness of 20 nm;

[0063] (3) The ITO spin-coated with the electron transport layer was placed in a nitrogen glove box and spin-coated with a perovskite precursor solution. The composition of the solution was PbI.sub.2, CsI, and PbBr.sub.2, and the composition concentration was 1.3 M CsPbI.sub.2Br solution; the solvent was pure DMSO; the precursor solution was stirred for two hours and filtered and ready for use; the spin coating speed was 3000 rpm and the time is 30 s. After the spin coating was completed, a gradient annealing was performed, first annealing at 50° C. for 1 minute, then annealing at 100° C. for 1 minute, and finally annealing at 160° C. for 10 minutes to obtain an inorganic perovskite film; compared with a one-step annealing process; FIG. 1 shows a direct one-step high-temperature annealing (160° C./10 min or 100° C./12 min) and a gradient annealing (50° C./1 min+100) ° C./1 min+160° C./10 min). It can be seen from the figure that the surface of the film directly annealed at high temperature is very rough, while the surface of the gradient annealed film is smooth, which illustrates the importance of gradient annealing to improve the quality of the film;

[0064] FIG. 2 is a scanning electron microscope (SEM) image of an inorganic perovskite thin film directly subjected to one-step high-temperature annealing and gradient annealing. As can be seen from the figure, the film coverage of direct high-temperature annealing is low, while the film coverage of gradient annealing is high and has good film formation;

[0065] (4) The obtained perovskite film was placed on a vacuum chuck and spin-coated with Spiro-OMeTAD (2,2′,7,7′-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9′-spirobi-fluorene) as a hole-transporting layer, rotating at 3000 rpm for 30 seconds, and then oxidizing in dry air for 12 hours to obtain a hole-transporting layer having a thickness of 150 nm;

[0066] (5) The oxidized hole-transporting layer was placed in a coating machine to deposit an Au electrode with a thickness of 80 nm.

[0067] At this point, the preparation of the CsPbI.sub.2Br perovskite battery is completed. The structure is shown in FIG. 3. The blank indicates no antisolvent treatment, and toluene and isopropanol indicate that they have been treated with toluene and isopropanol, respectively. It can be seen that a perovskite film thickness of 500 nm.

[0068] FIG. 4 and Table 1 are the efficiency table and J-V curve chart of direct high temperature annealing (160° C./10 min) and gradient annealing of CsPbI.sub.2Br perovskite battery. It can be seen that the film forming properties of the thin film directly annealed at a high temperature are extremely poor, so the performance parameters of the battery are not good, which is mainly due to the direct contact between the upper and lower transport layers caused by the poor film coverage of the perovskite. The performance of the gradient-annealed perovskite battery is superior, which is comparable to the highest efficiency of the inorganic perovskite battery reported; the PCE of the battery after direct high temperature annealing at 100° C. is 3.49%.

TABLE-US-00001 TABLE 1 Performance of inorganic perovskite batteries prepared by direct high temperature annealing and gradient annealing V.sub.oc (V) J.sub.sc (mA/Cm.sup.2) FF (%) PCE (%) Direct High 0.79 7.28 46.1 3.49 Temperature Annealing Gradient Annealing 1.13 15.45 72.43 12.65

Example 2

[0069] (1) A rigid substrate of glass was used for polishing, and then a layer of indium tin oxide film was plated on the glass by a magnetron sputtering method to form an ITO conductive glass as a cathode of a solar cell;

[0070] (2) Spin-coating TiO.sub.2 solution on ITO conductive glass, 3000 rpm 30 s, and then annealing at 150° C. for 30 min to obtain an electron transport layer with a thickness of 20 nm;

[0071] (3) The ITO spin-coated with the electron transport layer was placed in a nitrogen glove box to spin-coat the perovskite precursor solution. The components of the precursor solution were PbI.sub.2, CsI and PbBr.sub.2, and the composition concentration was 1.3 M of CsPbI.sub.2Br solution; the solvent was pure DMSO; the precursor solution was stirred for two hours and then filtered and used. The spin coating rate was 3000 rpm and the time was 30 s. When spin coating was performed for 20 s, 150 of isopropyl alcohol or toluene solution was added dropwise. After the spin coating was completed, gradient annealing was performed. The film was annealed at 50° C. for 1 minute, and then annealed at 100° C. for 1 minute, and finally annealed at 160° C. for 10 minutes to obtain an inorganic perovskite film. It is worth mentioning that if there is no gradient annealing process, the solution is annealed at 100° C. or higher directly after the antisolvent is added dropwise. The SEM image is shown in FIG. 5. The grains cannot completely cover the entire film, and the pores are large. This is similar to the SEM morphology of direct high temperature annealing without the addition of an anti-solvent. The PCE for preparing the battery was 5.73%. When 80° C./1 min+120° C./8 min was selected, the PCE of the battery was 6.83%; this further proves the importance of the gradient annealing of the present invention to the film quality.

[0072] In situ characterization of films treated with different antisolvents is shown in FIG. 6. When annealing at 50° C. in the first stage of gradient annealing, compared with films not treated with antisolvent (blank), toluene or isopropyl alcohol (IPA) treated film is more uniform during crystallization; the SEM image also shows that the anti-solvent-treated film has a flatter film and larger grains after the first-stage annealing (FIG. 7); after the entire gradient annealing is completed, when anti-solvent is not added, the processed film has more stripes on the edges, which is mainly caused by uneven annealing of the film, and the optical microscope and SEM images at these stripes show more holes (FIG. 8). The influence is great. Compared to the center of the blank film, the optical microscope and SEM images show a denser film; and the film treated with toluene or isopropanol is more uniform during the first annealing (especially isopropanol). The resulting film has a smaller surface roughness, and the entire film is very uniform, and the edges have no white uneven stripes, which provides a guarantee for high-performance devices.

[0073] FIG. 9 is an image of the specular reflection of the isopropanol-treated film, which fully illustrates the uniformity and flatness of the film; FIG. 10 is a SEM image of the film treated with different anti-solvents. Grade-sized grains are far superior to perovskite films without anti-solvent treatment or toluene treatment. This is also the reason for the excellent performance of isopropanol-treated devices. Related device parameters and JV curves are shown in Table 2 and FIG. 11. A simulated plot of gradient annealing and antisolvent synergy is shown in FIG. 12. It is shown that the present invention can use a high-concentration precursor solution and a high rotation speed to obtain a high-thickness, high-quality perovskite film, which overcomes the technical defects of the prior art that a thin film with a high thickness can be obtained at a low rotation speed and solves the problem. The existing perovskite film has many technical defects such as more pores and smaller grains, and has achieved unexpected technical effects.

[0074] (4) The perovskite film was placed on a vacuum chuck, and the Spiro-OMeTAD hole transport layer was spin-coated at a speed of 3000 rpm and 30 s, and oxidized in dry air for 12 hours to obtain a hole transport layer with a thickness of 150 nm;

[0075] (5) The oxidized hole-transport layer was placed in a coating machine to vapor-deposit an Au electrode with a thickness of 80 nm. At this point, the preparation of the CsPbI.sub.2Br perovskite battery was completed. The structure of the device treated with different antisolvents is shown in FIG. 3. It can be seen from the figures that the thickness of the perovskite thin film reached 500 nm under three conditions, and the isopropanol-treated device thin film had fewer grain boundaries, which was beneficial to the improvement of performance.

[0076] The crystal quality of the thin films treated with different anti-solvents is inconsistent, resulting in different device stability, as shown in FIG. 13. Stored at 25° C. and 30% humidity for 1000 hours, the IPA-treated device can maintain 95% of the initial efficiency, the toluene-treated device can maintain 70% of the initial efficiency, and the blank device efficiency decays to 56% of the initial efficiency. It can be seen that the quality of the crystal has a great impact on the stability of the device, and larger grains with fewer defect states help to suppress the degradation of the thin film itself, so that the device performance remains stable. In the present invention, during the preparation of the perovskite thin film, the concentration and composition of the precursor solution can be adjusted, and details are not described herein.

TABLE-US-00002 TABLE 2 Device performance with different antisolvent treatments V.sub.oc (V) J.sub.sc (mA/Cm.sup.2) FF (%) PCE (%) Blank 1.13 15.45 72.43 12.65 Toluene 1.19 15.75 73.71 13.82 Isopropanol 1.23 16.79 77.81 16.07

[0077] The invention adopts gradient annealing and green anti-solvent to treat the inorganic perovskite thin film to obtain a thin film with larger crystal grains, higher purity and better stability. The inorganic perovskite film prepared by this method has good thermal stability, does not degrade at high temperature, and has good stability at lower humidity; and the efficiency of the inorganic perovskite battery prepared by this method It has exceeded 16% and is the highest efficiency in the field of inorganic perovskite.