Method for recycling lead iodide and substrate of waste perovskite device

Abstract

Provided is a method for recycling lead iodide and a substrate of a waste perovskite device. The method includes steps as follows: preparing an iodide solution having a set concentration; immersing the waste perovskite device in the iodide solution for dissolution until a perovskite substance of the waste perovskite device is not dissolved, and extracting supernatant; adding water to the supernatant for dilution, and obtaining lead iodide crystals containing a small quantity of impurities; washing the lead iodide crystals containing a small quantity of impurities, adding acid to treat the lead iodide crystals, washing the lead iodide crystals with isopropanol and ether to obtain lead iodide powder, and drying the lead iodide powder to obtain obtaining recycled lead iodide; and cleaning and recycling a substrate generated. The lead iodide is recycled according to Le Chatelier's principle, which achieves safe, environmentally friendly and low-cost recycling.

Claims

1. A method for recycling lead iodide and a substrate of a waste perovskite device, comprising steps as follows: Step 1: preparing a concentrated solution or saturated solution of iodide, wherein the iodide is one of potassium iodide, sodium iodide and ammonium iodide; Step 2: immersing the waste perovskite device in the iodide solution for dissolution until a perovskite substance of the waste perovskite device is not dissolved, and extracting supernatant; Step 3: adding water to the supernatant for dilution, and obtaining lead iodide crystals containing a small quantity of impurities; Step 4: washing the lead iodide crystals containing a small quantity of impurities, adding acid to treat the lead iodide crystals, washing the lead iodide crystals with isopropanol and ether to obtain lead iodide powder, and drying the lead iodide powder to obtain recycled lead iodide; and Step 5: cleaning and recycling a substrate generated in Step 2.

2. The method for recycling lead iodide and a substrate of a waste perovskite device according to claim 1, wherein according to Le Chatelier's principle, the lead iodide is dissolved in a high-concentration iodide solution, such that a soluble complex is obtained; and water is added for dilution, such that a concentration of iodide ions is reduced, and the lead iodide is recycled.

3. The method for recycling lead iodide and a substrate of a waste perovskite device according to claim 1, wherein in Step 4, the lead iodide crystals containing a small quantity of impurities are washed with water, a proper quantity of glacial acetic acid or formic acid is added to treat the lead iodide crystals, and the lead iodide crystals are washed with the isopropanol and then washed with the ether.

4. The method for recycling lead iodide and a substrate of a waste perovskite device according to claim 1, wherein in Step 4, the lead iodide crystals containing a small quantity of impurities are washed with water, a proper quantity of glacial acetic acid or formic acid is added to treat the lead iodide crystals, and the lead iodide crystals are washed with absolute ethyl alcohol and then washed with the ether.

5. The method for recycling lead iodide and a substrate of a waste perovskite device according to claim 1, wherein the substrate is one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO) and aluminum-doped zinc oxide (AZO).

6. The method for recycling lead iodide and a substrate of a waste perovskite device according to claim 1, wherein the substrate is one of a silicon cell layer in a perovskite and silicon stacked device and a copper indium gallium selenide cell layer in a perovskite and copper indium gallium selenide stacked device.

7. The method for recycling lead iodide and a substrate of a waste perovskite device according to claim 1, wherein a perovskite device is produced from the lead iodide obtained in Step 4 and the substrate obtained in Step 5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 shows a standard X-ray diffraction (XRD) spectrum of lead iodide and an XRD spectrum of lead iodide recycled through a method of the present disclosure and commercial high-purity lead iodide (SIGMA 99.99%).

[0025] FIG. 2 shows ultraviolet absorption spectra of a transparent conductive glass electrode recycled through a method of the present disclosure and a fresh transparent conductive glass electrode.

[0026] FIG. 3 shows a statistical chart of efficiency of devices produced from a material recycled through a method of the present disclosure and a fresh material.

[0027] FIG. 4 shows JV curves and performance parameters of devices produced from a material recycled through a method of the present disclosure and a fresh material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] Technical solutions of examples of the present disclosure will be clearly and completely described below in combination with accompanying drawings in the examples of the present disclosure. Apparently, the described examples are merely some examples rather than all examples of the present disclosure. All other examples derived by those of ordinary skill in the art on the basis of examples of the present disclosure all fall within the scope of protection of the present disclosure.

Example 1

[0029] Lead iodide and a transparent glass substrate were recycled from a device by using a concentrated solution of potassium iodide, as follows: [0030] Step 1: a potassium iodide solid was added to water at a room temperature, and stirred to be completely dissolved, and a concentrated solution or saturated solution of potassium iodide was prepared; [0031] Step 2: a waste device was immersed in the prepared solution at a room temperature for a certain time; it can be observed that a perovskite substance on an assembly was gradually dissolved, a substrate finally turned into colorless and transparent glass, and when the perovskite substance on the assembly in the solution was not dissolved, it can be assumed that the solution was in a saturated state; and at the time, precipitate B was generated at a bottom of the solution, a supernatant was colorless and transparent C, and the glass substrate was to be further treated; [0032] Step 3: supernatant C was separated out and diluted to a certain concentration by adding water, a golden precipitate generated in the process was low-purity lead iodide, and the generated low-purity lead iodide was to be further treated; [0033] Step 4: a certain quantity of water was added to the low-purity lead iodide for washing, which was to remove a soluble substance from the low-purity lead iodide and repeated for a certain quantity of times; a proper quantity of glacial acetic acid or formic acid was added for further treatment, such that a small quantity of basic or lead oxide generated in a generation process of lead iodide or a post-treatment process was removed; then washing was carried out with isopropanol, such that excess acetic acid and a small quantity of lead acetate were removed; finally, washing was carried out with ether, and powder was put in a vacuum oven at a set temperature for a period of time, such that high-purity lead iodide was obtained, and an XRD test result thereof is shown in FIG. 1; [0034] Step 5: transparent conductive glass electrodes produced in Step 2 were soaked in a weak acid solution, and cleaned with water, acetone and isopropanol respectively for later use, transmittance of recycled and fresh transparent substrates is tested as shown in FIG. 2, and the transmittance of the recycled substrate is equivalent to that of the fresh substrate; and [0035] Step 6: fresh and recycled ITOs were spin-coated with commercial SnO.sub.2 at a room temperature according to an experimental standard flow, annealing was carried out at 120? C. for 35 min, and an electron transport layer was produced for later use.

[0036] In addition, fresh commercial lead iodide and lead iodide recycled through the method were dissolved in a mixed solvent of DMSO and DMF (volume ratio is 4:1), a mixed solution having a concentration of 1.4 M was prepared, and stirring was carried out on a magnetic stirrer for complete dissolution, such that a clear and transparent solution was obtained.

[0037] Moreover, formamidinium iodide (FAI) (100 mg) and methylammonium chloride (MACl) (20 mg) were dissolved in isopropanol (IPA) (1 mL) at a room temperature, and stirring was carried out on a magnetic stirrer for complete dissolution, such that a clear and transparent solution was obtained.

[0038] Finally, an ITO substrate of a prepared electron transport layer was spin-coated with the above clear solution through a liquid-phase two-step spin-coating method, heating was carried out at 90? C. for 1 min, and then at 150? C. for 10 min, devices were produced from a fresh substrate, fresh lead iodide, recycled lead iodide and recycled ITO, and then performance of the devices were tested.

Example 2

[0039] Lead iodide and a transparent glass substrate were recycled from a device by using a concentrated solution of sodium iodide.

[0040] Steps and experimental conditions were the same as those in Example 1, and a difference was that sodium iodide is used as iodide.

Example 3

[0041] Lead iodide and a transparent silicon substrate were recycled from a perovskite and silicon cell stacked device by using a concentrated solution of potassium iodide.

[0042] Steps and experimental conditions were the same as those in Example 1, and a difference was that a recycled device is a perovskite cell and silicon cell stacked device.

[0043] Performance Comparison Experiment:

[0044] I. XRD Spectrum Testing:

[0045] The applicant carried out XRD spectrum testing on the high-purity lead iodide obtained in Step 4, and sampled commercial high-purity lead iodide (SIGMA 99.99%) for XRD spectrum testing. An obtained XRD spectrum was compared with a standard XRD spectrum, and a comparison result is shown in FIG. 1. It can be seen in combination with FIG. 1 that RECYCLED PbI.sub.2 in FIG. 1 represents a standard XRD spectrum of lead iodide, SIGMA PbI.sub.2 (SIGMA 99.99%) represents commercial high-purity lead iodide (SIGMA 99.99%), PDF #07-0235 represents lead iodide in the solution, and the recycled lead iodide in the solution has relatively high quality (20=43.4 is a background signal of a testing substrate).

[0046] II. Ultraviolet Spectrum Testing of Substrate:

[0047] The applicant made ultraviolet absorption spectra of a transparent conductive glass electrode recycled in the solution and a fresh transparent conductive glass electrode. As shown in FIG. 2, it can be seen that the substrate recycled through the method presents almost the same transmittance, which indicates feasibility and effectiveness of recycling the substrate through the method.

[0048] III. Efficiency Testing of Device:

[0049] The applicant produced a new perovskite device by using a substrate and lead iodide recycled in the solution, and compared efficiency thereof with that of a perovskite device produced from a fresh material, and a statistical result is shown in FIG. 3. It can be seen that a reference graph (REF) represents a device produced from fresh lead iodide and a fresh substrate, and average efficiency is 18.5%. An experimental group (RECYCLED) represents a device produced from a recycled substrate and recycled lead iodide, and average efficiency is 17.4%. The efficiency of the device produced from the recycled materials is slightly lower than that of the device produced from the fresh material, but the conversion efficiency is also relatively high.

[0050] IV. Performance Testing of Device:

[0051] The applicant produced a new perovskite device by using a substrate and lead iodide recycled in the solution, and compared performance thereof with that of a perovskite device produced from a fresh material, and a result is shown in FIG. 4. Ref corresponds to a JV curve of a device produced from fresh lead iodide and substrate in Example 1, Recycled corresponds to a JV curve of a device produced from recycled lead iodide and substrate in Example 1, and efficiency of the two devices is 18.63% and 17.71% respectively.

[0052] The present disclosure is not limited to the above-mentioned optimum embodiment, and anyone can obtain other products in various forms with the motivation of the present disclosure. However, no matter what change is made in its shape or structure, any technical solution identical or similar to that of the present disclosure falls within the scope of protection of the present disclosure.