Perovskite quantum dot and perovskite photovoltaic module
Through technical means of ligand exchange, ion doping and inorganic material encapsulation of perovskite quantum dots, the problems of insufficient stability and photoluminescence performance in practical applications are solved, and higher photoluminescence quantum yield and stability are achieved.
Patent Information
- Application Number
- CN202510302493.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-13
AI Technical Summary
In practical applications, perovskite quantum dots have problems such as dynamic instability of surface ligands, non-radiative recombination of ion migration and defective states, as well as insufficient environmental sensitivity and packaging technology, resulting in insufficient photoluminescent quantum yield and stability.
The steps of ligand exchange, ion doping and inorganic material wrapping of the perovskite billet include exchanging with long-chain insulating ligands using aminoisonicotinic acid, introducing zinc ion doping, and encapsulating the PbBrOH material on the outer layer to form a core-shell composite material to improve stability.
The photoluminescent quantum yield and stability of perovskite quantum dots has been significantly improved, enhancing its performance in high-efficiency photovoltaic applications.
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Abstract
Description
Technical Field
[0001] The present invention relates to a perovskite quantum dot and a perovskite photovoltaic module. Background Art
[0002] Perovskite Quantum Dots (PQDs) have become a research hotspot in the field of optoelectronic devices due to their excellent optoelectronic properties (such as high photoluminescence quantum yield (PLQY), tunable emission wavelength, and narrow full width at half maximum). However, their practical applications are still limited by the following core problems: 1. Insufficient dynamic stability of surface ligands: The synthesis of perovskite quantum dots usually relies on long-chain insulating ligands (such as oleic acid, oleylamine) to control the size and colloidal stability. However, the binding energy between these ligands and the quantum dot surface is relatively low, and they are prone to fall off during polar solvent treatment or environmental exposure. The ligand detachment not only leads to an increase in surface defect states (such as Pb 2+ or halogen vacancies) of the quantum dots, inhibits the transport of photo-generated carriers, but also causes quantum dot aggregation and a decrease in PLQY. In addition, traditional ligand exchange strategies such as using octanoic acid and lysine can partially replace long-chain ligands and improve charge coupling, but it is still difficult to balance ligand functionalization and long-term structural stability.
[0003] 2. Ionic migration and non-radiative recombination of defect states: The intrinsic ionic properties of perovskite quantum dots cause FA + , I - etc. to be prone to migration. Especially under light or electric fields, ionic migration will cause lattice distortion and vacancy defects, exacerbating non-radiative recombination. Although metal ion doping (such as K + , Mg² + ) can inhibit the migration of I - , the partial substitution of lead sites requires balancing the ionic radius and electronegativity matching. Otherwise, it may introduce lattice stress or new defects.
[0004] 3. Environmental sensitivity and deficiencies in encapsulation technology: The sensitivity of perovskite quantum dots to humidity and oxygen further restricts their stability. Existing encapsulation technologies (such as polymer coating, MOF encapsulation) can physically isolate environmental erosion, but they may sacrifice the light absorption ability or charge transport efficiency of quantum dots. For example, Pb-MOF-based encapsulation materials improve the stability of CsPbI3 through pore confinement effects, but the preparation process is complex and may reduce PLQY due to interfacial stress.
[0005] Therefore, solving the problems of photoluminescence quantum yield and stability of perovskite quantum dots is crucial for promoting their practical applications in high-efficiency photovoltaics. Summary of the Invention
[0006] The object of the present invention is to provide a perovskite quantum dot and a perovskite photovoltaic module to solve the technical problems mentioned in the above background art.
[0007] The technical solution for achieving the object of the present invention is as follows: In the first aspect, the present invention provides a perovskite quantum dot, which is obtained by performing ligand exchange, ion doping, and finally coating an inorganic material on the outer layer of a perovskite blank.
[0008] Further, the perovskite blank adopts MAPbBr3.
[0009] Further, the ligand exchange is to exchange the long-chain insulating ligands oleic acid and oleylamine in MAPbBr3 with aminoisonicotinic acid.
[0010] Further, the ion doping adopts Zn 2+ doping.
[0011] Further, the inorganic material coated on the outer layer is PbBrOH.
[0012] Further, the preparation steps of the perovskite quantum dot are as follows: (1) Preparation of perovskite blank: Dissolve equimolar lead bromide and methylammonium bromide in DMF, then add oleic acid and oleylamine and mix evenly, centrifuge at 9000 rpm for 5 min, take the precipitate to obtain the perovskite blank; (2) Ligand exchange: Disperse the perovskite blank obtained in step (1) in toluene with a mass 2 - 3 times that of the precipitate and shake evenly, then add acetonitrile with a volume of 1 / 3 of the toluene and aminoisonicotinic acid with a mass 0.4 - 0.6 times that of lead bromide in step (1), mix and stir for 5 - 15 min, centrifuge at 8000 rpm for 5 min, take the precipitate to obtain the perovskite blank after ligand exchange; (3) Ion doping: Add the perovskite blank after ligand exchange obtained in step (2) to a DMF solution of zinc nitrate hexahydrate and ultrasonically oscillate for 8 - 12 min to obtain a solution of the perovskite blank after ion doping; (4) Inorganic material coating: Add a DMF solution of lead bromide to the solution of the perovskite blank after ion doping obtained in step (3), stir and mix for 60 - 70 min, then centrifuge at 5000 rpm for 5 min, wash thoroughly with DMF and vacuum dry at 60 °C for 10 - 14 h to obtain the perovskite quantum dot.
[0013] Further, in step (1), the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:258 - 260, and the molar ratio of lead bromide to methylammonium bromide is equimolar.
[0014] Further, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:18 - 20; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.42 - 0.64 times the mass of lead bromide in step (1).
[0015] Further, the concentration of the DMF solution of lead bromide in step (4) is 1.4 - 1.6 wt%; the mass of lead bromide in the DMF solution of lead bromide is 0.7 - 0.8 times the mass of lead bromide in step (1).
[0016] In the second aspect, the present invention provides a perovskite photovoltaic module, which is prepared from the perovskite quantum dots of the first aspect.
[0017] By adopting the above technical solutions, the present invention has the following beneficial effects: (1) The perovskite quantum dots of the present invention are obtained by sequentially performing ligand exchange, ion doping, and finally coating an inorganic material on the perovskite blank. The prepared perovskite quantum dots have a relatively high photoluminescence quantum yield and good stability.
[0018] (2) There are a large number of insulating long-chain ligands in MAPbBr3, which hinder the extraction and transport of photo-generated carriers. Moreover, in the process of quantum dot purification or application, strong polar solvents are likely to strip the long-chain ligands from the surface of the quantum dots, causing the quantum dots to aggregate or degrade, thereby reducing the PLQY and stability; in the perovskite blank of the present invention, aminoisonicotinic acid is used to exchange with the long-chain insulating ligands oleic acid and oleylamine in MAPbBr3; a part of the carboxyl group of aminoisonicotinic acid + interacts with MA 2+ to inhibit the migration of MA ions and stabilize the structure of perovskite quantum dots; another part of the carboxyl group of aminoisonicotinic acid binds to Pb - and the amino group adsorbed on the Pb atom interacts with Br through hydrogen bonds
[0019] (3) The present invention introduces zinc ion doping. The interaction between Zn 2+ and Br - passivates the defect states on the surface and inside of the nanocrystals and inhibits non-radiative recombination. After Zn 2+ replaces Pb 2+ , the interaction of the Pb-Br bond is weakened, the formation of vacancy defects is reduced, the doping improves the formation energy of perovskite crystals, and enhances the photoluminescence quantum yield, thermal stability and environmental stability of perovskite quantum dots; at the same time, part of the aminoisonicotinic acid in the perovskite blank after ligand exchange reacts with zinc nitrate to form aminoisonicotinic acid-based MOF. In the DMF solvent, the aminoisonicotinic acid-based MOF promotes the Zn in the MOF under electrostatic action 2+Combined with PbBr 2 the Br in - to form Zn-Br bonds, which weakens the original structure of PbBr 2 and promotes the phase change of PbBr 2 to generate the cubic PbO-PbBr 2 phase. The phase change product PbO-PbBr 2 continues to hydrolyze or react further in the reaction solution system and gradually transforms into the PbBrOH phase. PbBrOH wraps MAPbBr 3 quantum dots through self-assembly to form a core-shell composite material. The stable structure of the core-shell composite material effectively protects the quantum dots and improves the photoluminescence performance. Specific embodiments
[0020] To better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific embodiments.
[0021] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.
[0022] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.
[0023] Some raw materials of the embodiments and comparative examples of the present invention are as follows: Under ice bath conditions, methylamine solution and hydrobromic acid solution are mixed and stirred at a molar ratio of methylamine to hydrobromic acid of 1:1 for 60 min. Subsequently, the solvent is removed by heating at 60 °C in a vacuum environment using a rotary evaporator, washed 3 times with ether, and dried at 60 °C in a vacuum environment for 6 h to obtain methylammonium bromide.
[0024] (Example 1) A perovskite quantum dot is prepared according to the following steps: (1) Preparation of perovskite blank: Lead bromide and methylammonium bromide in equimolar amounts are dissolved in DMF, and then oleic acid and oleylamine are added and mixed evenly, centrifuged at 9000 rpm for 5 min, and the precipitate is taken to obtain the perovskite blank; wherein, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:258, and lead bromide and methylammonium bromide are in an equimolar ratio; (2) Ligand exchange: The perovskite blank obtained in step (1) is then dispersed in toluene with a mass 2 times that of the precipitate and shaken evenly. Then, acetonitrile with 1 / 3 of the toluene volume and 4-aminopyridine-3-carboxylic acid with 0.4 times the mass of lead bromide in step (1) are added and mixed and stirred for 5 min, and then centrifuged at 8000 rpm for 5 min, and the precipitate is taken to obtain the perovskite blank after ligand exchange; (3) Ion doping: The ligand-exchanged perovskite blank prepared in step (2) is added to a DMF solution of zinc nitrate hexahydrate and ultrasonically oscillated for 8 min to obtain an ion-doped perovskite blank solution; wherein, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:18; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.42 times the mass of lead bromide in step (1). (4) Inorganic material coating: A DMF solution of lead bromide with a concentration of 1.4 wt% is added to the ion-doped perovskite blank solution prepared in step (3), stirred and mixed for 60 min, then centrifuged at 5000 rpm for 5 min, washed thoroughly with DMF, and vacuum-dried at 60 °C for 10 h to obtain perovskite quantum dots; wherein, the mass of lead bromide in the DMF solution of lead bromide is 0.7 times the mass of lead bromide in step (1).(5) (6)
[0025] (Example 2)(7) A kind of perovskite quantum dots, the preparation steps are as follows:(8) (1) Preparation of perovskite blank: Equimolar lead bromide and methylammonium bromide are dissolved in DMF, then oleic acid and oleylamine are added and mixed evenly, centrifuged at 9000 rpm for 5 min, and the precipitate is taken to obtain a perovskite blank; wherein, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:259, and the molar ratio of lead bromide to methylammonium bromide is equal.(9) (2) Ligand exchange: The perovskite blank prepared in step (1) is then dispersed in toluene with a mass 2.5 times that of the precipitate and oscillated evenly, then acetonitrile with 1 / 3 of the volume of toluene and 0.5 times the mass of lead bromide in step (1) of aminoisonicotinic acid are added and stirred for 10 min, then centrifuged at 8000 rpm for 5 min, and the precipitate is taken to obtain a ligand-exchanged perovskite blank.(10) (3) Ion doping: The ligand-exchanged perovskite blank prepared in step (2) is added to a DMF solution of zinc nitrate hexahydrate and ultrasonically oscillated for 10 min to obtain an ion-doped perovskite blank solution; wherein, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:19; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.52 times the mass of lead bromide in step (1).(11) (4) Inorganic material coating: A DMF solution of lead bromide with a concentration of 1.5 wt% is added to the ion-doped perovskite blank solution prepared in step (3), stirred and mixed for 65 min, then centrifuged at 5000 rpm for 5 min, washed thoroughly with DMF, and vacuum-dried at 60 °C for 12 h to obtain perovskite quantum dots; wherein, the mass of lead bromide in the DMF solution of lead bromide is 0.75 times the mass of lead bromide in step (1).(12) (13)
[0026] (Example 3)(14) A perovskite quantum dot, the preparation steps are as follows: (1) Preparation of perovskite blank: Dissolve equimolar lead bromide and methylammonium bromide in DMF, then add oleic acid and oleylamine and mix evenly, centrifuge at 9000 rpm for 5 min, and take the precipitate to obtain the perovskite blank; wherein, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:260, and the molar ratio of lead bromide to methylammonium bromide is equal; (2) Ligand exchange: Disperse the precipitate obtained in step (1) of the perovskite blank in toluene with a volume 3 times its mass and shake evenly, then add acetonitrile with a volume of 1 / 3 of the toluene and 0.6 times the mass of lead bromide in step (1) of aminoisonicotinic acid and mix and stir for 15 min, then centrifuge at 8000 rpm for 5 min, and take the precipitate to obtain the ligand-exchanged perovskite blank; (3) Ion doping: Add the ligand-exchanged perovskite blank obtained in step (2) to the DMF solution of zinc nitrate hexahydrate and ultrasonically oscillate for 12 min to obtain the ion-doped perovskite blank solution; wherein, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:20; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.64 times the mass of lead bromide in step (1); (4)Inorganic material coating: Add a DMF solution containing 1.6 wt% lead bromide to the ion-doped perovskite blank solution obtained in step (3), stir and mix for 70 min, then centrifuge at 5000 rpm for 5 min, wash thoroughly with DMF and vacuum dry at 60 °C for 14 h to obtain perovskite quantum dots; wherein, the mass of lead bromide in the DMF solution of lead bromide is 0.8 times the mass of lead bromide in step (1).
[0027] (Comparative Example 1) A perovskite quantum dot, the preparation steps are as follows: (1)Preparation of perovskite blank: Dissolve equimolar lead bromide and methylammonium bromide in DMF, then add oleic acid and oleylamine and mix evenly, centrifuge at 9000 rpm for 5 min, and take the precipitate to obtain the perovskite blank; wherein, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:259, and the molar ratio of lead bromide to methylammonium bromide is equal; (2)Ligand exchange: Disperse the precipitate obtained in step (1) of the perovskite blank in toluene with a volume 2.5 times its mass and shake evenly, then add acetonitrile with a volume of 1 / 3 of the toluene and 0.5 times the mass of lead bromide in step (1) of lysine and mix and stir for 10 min, then centrifuge at 8000 rpm for 5 min, and take the precipitate to obtain the ligand-exchanged perovskite blank; (3) Ion doping: The ligand-exchanged perovskite blank prepared in step (2) was added to a DMF solution of zinc nitrate hexahydrate and ultrasonically oscillated for 10 min to obtain an ion-doped perovskite blank solution; wherein, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:19; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.52 times the mass of lead bromide in step (1). (4) Inorganic material coating: A DMF solution containing 1.5 wt% lead bromide was added to the ion-doped perovskite blank solution prepared in step (3), stirred and mixed for 65 min, centrifuged at 5000 rpm for 5 min, washed thoroughly with DMF, and vacuum dried at 60 °C for 12 h to obtain perovskite quantum dots; wherein, the mass of lead bromide in the DMF solution of lead bromide is 0.75 times the mass of lead bromide in step (1).
[0028] (Comparative Example 2) A kind of perovskite quantum dots, the preparation steps are as follows: (1) Preparation of perovskite blank: Equimolar amounts of lead bromide and methylammonium bromide were dissolved in DMF, then oleic acid and oleylamine were added and mixed evenly, centrifuged at 9000 rpm for 5 min, and the precipitate was taken to obtain the perovskite blank; wherein, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:259, and the molar ratio of lead bromide to methylammonium bromide is equal. (2) Ion doping: The perovskite blank prepared in step (1) was added to a DMF solution of zinc nitrate hexahydrate and ultrasonically oscillated for 10 min to obtain an ion-doped perovskite blank solution; wherein, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:19; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.52 times the mass of lead bromide in step (1). (3) Inorganic material coating: A DMF solution containing 1.5 wt% lead bromide was added to the ion-doped perovskite blank solution prepared in step (2), stirred and mixed for 65 min, centrifuged at 5000 rpm for 5 min, washed thoroughly with DMF, and vacuum dried at 60 °C for 12 h to obtain perovskite quantum dots; wherein, the mass of lead bromide in the DMF solution of lead bromide is 0.75 times the mass of lead bromide in step (1).
[0029] (Comparative Example 3) A kind of perovskite quantum dots, the preparation steps are as follows: (1)Preparation of perovskite blank: Dissolve equimolar lead bromide and methylammonium bromide in DMF, then add oleic acid and oleylamine and mix evenly. Centrifuge at 9000 rpm for 5 min, and take the precipitate to obtain the perovskite blank; among them, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:259, and the molar ratio of lead bromide to methylammonium bromide is equal. (2)Ligand exchange: Disperse the precipitate obtained in step (1) of the perovskite blank in toluene with a mass 2.5 times that of the precipitate, shake evenly, then add acetonitrile with a volume of 1 / 3 of the toluene volume and 4-aminoisonicotinic acid with a mass 0.5 times that of lead bromide in step (1), mix and stir for 10 min, then centrifuge at 8000 rpm for 5 min, and take the precipitate to obtain the perovskite blank after ligand exchange. (3)Inorganic material coating: Add a DMF solution containing 1.5 wt% lead bromide to the perovskite blank after ligand exchange obtained in step (2), stir and mix for 65 min, then centrifuge at 5000 rpm for 5 min, wash thoroughly with DMF, and vacuum dry at 60 °C for 12 h to obtain perovskite quantum dots; among them, the mass of lead bromide in the DMF solution of lead bromide is 0.75 times the mass of lead bromide in step (1).
[0030] (Comparative Example 4) A kind of perovskite quantum dots, the preparation steps are as follows: (1)Preparation of perovskite blank: Dissolve equimolar lead bromide and methylammonium bromide in DMF, then add oleic acid and oleylamine and mix evenly. Centrifuge at 9000 rpm for 5 min, and take the precipitate to obtain the perovskite blank; among them, the mass ratio of lead bromide, oleic acid, oleylamine, and DMF is 1:2.4:1.1:259, and the molar ratio of lead bromide to methylammonium bromide is equal. (2)Ligand exchange: Disperse the precipitate obtained in step (1) of the perovskite blank in toluene with a mass 2.5 times that of the precipitate, shake evenly, then add acetonitrile with a volume of 1 / 3 of the toluene volume and 4-aminoisonicotinic acid with a mass 0.5 times that of lead bromide in step (1), mix and stir for 10 min, then centrifuge at 8000 rpm for 5 min, and take the precipitate to obtain the perovskite blank after ligand exchange. (3)Ion doping: Add the perovskite blank after ligand exchange obtained in step (2) to a DMF solution of zinc nitrate hexahydrate and ultrasonically oscillate for 10 min to obtain a solution of the perovskite blank after ion doping; among them, the mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:19; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.52 times the mass of lead bromide in step (1). (4)Centrifuge the solution of the perovskite blank after ion doping obtained in step (3) at 5000 rpm for 5 min, wash thoroughly with DMF, and vacuum dry at 60 °C for 12 h to obtain perovskite quantum dots.
[0031] (Blank Example 1) The perovskite quantum dots of Blank Example 1 adopt MAPbBr 3 quantum dots.
[0032] (Effect Example) PLQY: The absolute quantum yields of the perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1 were measured using a QEpro type quantum yield tester equipped with an integrating sphere. For the PL spectrum test of the powder sample, the perovskite quantum dots were placed in the center of a quartz sample stage, and the sample stage was placed in the integrating sphere. After setting parameters such as the emission wavelength range of the perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1, the test can be carried out.
[0033] The solvent stability test refers to characterizing and comparing the PLQY of the perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1 before and after soaking in the polar solvent acetonitrile for 15 days. The solvent stability of the sample was characterized and explained by the decrease in the optical properties of the powder before and after soaking. The retention rate (%) of PLQY after soaking = 100% * (PLQY after soaking / PLQY before soaking).
[0034] The light stability refers to comparing the PL intensities before and after irradiating the perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1 continuously under a UV lamp with a wavelength of 365 nm for 40 days. The stability of the sample under light was explained by the change in the peak intensity in the P spectrum. The retention rate (%) of the PL intensity after light irradiation = 100% * (PL intensity after light irradiation / PL intensity before light irradiation).
[0035] Thermal stability: The perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1 were heated from 300 K to 420 K and then cooled to room temperature, and the PL intensities before and after heating were compared. The retention rate (%) of the PL intensity after heating = 100% * (PL intensity after heating / PL intensity before heating).
[0036] The following Table 1 shows the performance data results of the perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1:
[0037] Comparing the performance data of the perovskite quantum dots of Examples 1 to 3, Comparative Examples 1 to 4, and Blank Example 1 in Table 1 above, the photoluminescence quantum yields of Examples 1 to 3 are higher and the stability is better.
[0038] Among them, the difference between Comparative Example 1 and Example 2 is that Comparative Example 1 uses lysine instead of aminoisonicotinic acid, and aminoisonicotinic acid-based MOF cannot be formed during the preparation of perovskite quantum dots, and thus cannot be in MAPbBr3 The surface is completely coated with PbBrOH, and the perovskite quantum dots prepared in Example 2 of Comparative Example 1 have a relatively high photoluminescence quantum yield and good stability; The difference between Comparative Example 2 and Example 2 is that ligand exchange was not carried out during the preparation of perovskite quantum dots in Comparative Example 1, and the residual long-chain ligands hindered the carrier transport, introducing Zn 2+ Although it has a certain defect passivation effect, since the surface defects are not completely repaired and the aminoisonicotinic acid-based MOF cannot be formed during the preparation of perovskite quantum dots, and thus cannot be formed on MAPbBr 3 The surface is completely coated with PbBrOH, and the perovskite quantum dots prepared in Example 2 of Comparative Example 2 have a relatively high photoluminescence quantum yield and good stability; The difference between Comparative Example 3 and Example 2 is that Zn doping was omitted during the preparation of perovskite quantum dots in Comparative Example 1, and the aminoisonicotinic acid-based MOF cannot be formed during the preparation of perovskite quantum dots, and thus cannot be formed on MAPbBr 2+ doping, and the aminoisonicotinic acid-based MOF cannot be formed during the preparation of perovskite quantum dots, and thus cannot be formed on MAPbBr 3 The surface is completely coated with PbBrOH, and the perovskite quantum dots prepared in Example 2 of Comparative Example 3 have a relatively high photoluminescence quantum yield and good stability; The difference between Comparative Example 4 and Example 2 is that inorganic coating was not carried out during the preparation of perovskite quantum dots in Comparative Example 1, but a MOF structure was formed on the surface of the perovskite quantum dots for protection. The perovskite quantum dots prepared in Example 2 of Comparative Example 4 have a relatively high photoluminescence quantum yield and good stability; In summary, the perovskite quantum dots of the present invention are obtained by first performing ligand exchange on the long-chain insulating ligands oleic acid and oleylamine in MAPbBr3 with aminoisonicotinic acid, then doping with zinc ions, and finally coating PbBrOH on the outer layer. During this process, the ligand exchange of aminoisonicotinic acid, zinc ion doping, and inorganic layer coating act synergistically, resulting in higher photoluminescence quantum yield and better stability of the prepared perovskite quantum dots.
[0039] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A perovskite quantum dot, characterized in that: The perovskite quantum dots are obtained by subjecting perovskite blanks to ligand exchange, ion doping and finally wrapping an inorganic material in an outer layer.
2. The perovskite quantum dot according to claim 1, characterized in that The perovskite blank adopts MAPbBr3.
3. The perovskite quantum dot according to claim 1, characterized in that The ligand exchange is carried out by using aminoisonicotinic acid to exchange with the long-chain insulating ligands oleic acid and oleylamine in MAPbBr3.
4. The perovskite quantum dot according to claim 1, characterized in that The ion doping method uses Zn 2+ Doping.
5. The perovskite quantum dot according to claim 1, characterized in that: The inorganic material wrapped in the outer layer is PbBrOH.
6. The perovskite quantum dot according to claim 1, characterized in that: The preparation steps of the perovskite quantum dots are as follows: (1) Preparation of perovskite blank: Dissolve equimolar amounts of lead bromide and methyl ammonium bromide in DMF, then add oleic acid and oleylamine and mix well. Centrifuge at 9000 rpm for 5 min, collect the precipitate, and obtain the perovskite blank. (2) Ligand exchange: The perovskite blank prepared in step (1) is then dispersed in toluene with a mass of 2 to 3 times the mass thereof and shaken evenly. Then, acetonitrile with a mass of 1 / 3 of the mass of toluene and aminoisonicotinic acid with a mass of 0.4 to 0.6 times the mass of the lead bromide in step (1) are added and stirred for 5 to 15 minutes. The mixture is then centrifuged at 8000 rpm for 5 minutes, and the precipitate is collected to obtain a perovskite blank after ligand exchange. (3) Ion doping: adding the ligand-exchanged perovskite blank obtained in step (2) to a DMF solution of zinc nitrate hexahydrate and subjecting it to ultrasonic oscillation for 8 to 12 minutes to obtain an ion-doped perovskite blank solution; (4) Inorganic material coating: Add the DMF solution of lead bromide to the ion-doped perovskite blank solution obtained in step (3), stir and mix for 60 to 70 minutes, centrifuge at 5000 rpm for 5 minutes, wash thoroughly with DMF, and vacuum dry at 60°C for 10 to 14 hours to obtain perovskite quantum dots.
7. The perovskite quantum dot according to claim 6, characterized in that: The mass ratio of lead bromide, oleic acid, oleylamine and DMF in step (1) is 1:2.4:1.1:258-260, and the molar ratio of lead bromide to methyl ammonium bromide is equimolar.
8. The perovskite quantum dot according to claim 6, characterized in that The mass ratio of zinc nitrate hexahydrate to DMF in the DMF solution of zinc nitrate hexahydrate is 1:18-20; the mass of zinc nitrate hexahydrate in the DMF solution of zinc nitrate hexahydrate is 0.42-0.64 times the mass of lead bromide in step (1).
9. The perovskite quantum dot according to claim 6, characterized in that: The concentration of the lead bromide solution in the DMF solution of step (4) is 1.4-1.6 wt %; the mass of lead bromide in the lead bromide solution of DMF is 0.7-0.8 times the mass of lead bromide in step (1).
10. A perovskite photovoltaic module, characterized in that: The perovskite photovoltaic module is made from the perovskite quantum dots according to any one of claims 1 to 9.