WO2023126684A1

WO2023126684A1 - Dual emission perovskite quantum dots

Info

Publication number: WO2023126684A1
Application number: PCT/IB2022/050007
Authority: WO
Inventors: Meysam SAEEDI; Vahid Ahmadi; Farzaneh ARABPOUR; Tahereh Ashjari; Ahdieh Amjadi
Original assignee: Saeedi Meysam; Vahid Ahmadi; Arabpour Farzaneh; Tahereh Ashjari; Ahdieh Amjadi
Priority date: 2022-01-02
Filing date: 2022-01-02
Publication date: 2023-07-06

Abstract

A method for in-situ synthesis of dual-emission perovskite quantum dots may include forming a precursor solution and spraying the precursor solution onto a target substrate. The precursor solution may be formed by obtaining a first solution by dissolving a polymer in an organic solvent, obtaining a second solution by mixing an inorganic metal halide solution, an organic amine halide solution, and a doping metal halide solution, and mixing the first solution and the second solution.

Description

DUAL EMISSION PEROVSKITE QUANTUM DOTS

TECHNICAL FIELD

[0001] The present disclosure relates to dual emission perovskite quantum dots, particularly to an in-situ method for synthesizing dual emission perovskite quantum dots. More particularly, the present disclosure relates to a method for covering a target surface with a spray-on layer of dual emission perovskite quantum dots.

BACKGROUND

[0002] Nanocrystal-based or quantum dots-based luminophores exhibit improved photoluminescence (PL) intensity, emission spectrum tunability, wide absorption range, and low full width half maximum (FWHM) in comparison with other luminophores. The aforementioned properties make nanocrystal-based or quantum dots-based luminophores suitable for sensor applications. Nanocrystal-based or quantum dots-based luminophores may be synthesized by colloidal synthesis methods. However, such colloidally synthesized luminophores may need to be extracted from the colloidal solution and carefully purified to remove excess precursors and surfactants before they can be used. These separation and purification steps, which are time-consuming, and complex may adversely affect the luminescent properties of the synthesized luminophores.

[0003] Some applications require a thin layer of luminescent film deposited onto a substrate. To form a thin luminescent film, a precursor must be formed and coated onto a target substrate. Then, heat treatment and solvent extraction usually takes place to achieve a uniform layer on the target substrate. Maintaining the uniformity of a deposited thin layer of perovskite quantum dots and preventing the deposited thin layer from clustering is challenging. To address the uniformity problem an in-situ method must be developed that may allow for simultaneous doping and formation of quantum dots. One approach may be the use of templates such as porous silica matrix. Although this approach is in-situ, preparing a porous structure, which is done separately, is costly and time consuming. Furthermore, in this approach the target substrate must be porous, and it is not possible to deposit the layer onto any given substrate. Another approach is the so-called one-pot synthesis method, which requires a tight control over the ambient conditions and poor repeatability due to the dependence of doping on various parameters. [0004] There is, therefore, a need for an in-situ method for synthesizing dual-emission perovskite quantum dots that may allow for an easy deposition of a thin layer of quantum dots over any given substrate utilizing a user-friendly method, such as spraying the layer over the substrate utilizing a handheld portable spray.

SUMMARY

[0005] This summary is intended to provide an overview of the subject matter of the present disclosure and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of the claimed implementations. The proper scope of the present disclosure may be ascertained from the claims set forth below in view of the detailed description and the drawings.

[0006] According to one or more exemplary embodiments, the present disclosure is directed to a method for in-situ synthesis of dual-emission perovskite quantum dots. An exemplary method may include forming a precursor solution and spraying an exemplary precursor solution onto a target substrate. An exemplary precursor solution may be formed by obtaining a first solution by dissolving a polymer in a first organic solvent, obtaining a second solution by mixing an inorganic metal halide solution, an organic amine halide solution, and a doping metal halide solution, and mixing an exemplary first solution and an exemplary second solution.

[0007] In an exemplary embodiment, an exemplary inorganic metal halide solution may include an inorganic metal chloride with a formula of YCh and a second inorganic metal halide with a formula of YX2. X may include at least one of I, Br, and SCN, and Y may include at least one of Cu, Pb, Sn, and Ge.

[0008] In an exemplary embodiment, an exemplary inorganic metal halide solution may include an inorganic metal halide chloride and a second inorganic metal halide, such that a molar ratio of an exemplary second inorganic metal halide to an exemplary inorganic metal halide chloride may be in a range of 0.1 to 0.5.

[0009] In an exemplary embodiment, an exemplary doping metal halide solution may include a doping metal that may be one of Mn, Eu, Er, Yb, Dy, Tb, Sm, Ce, and Zn. In an exemplary embodiment, an exemplary doping metal halide solution may further include at least one of Bi, Cd, Al, Ca, Mg, K, Sb, In, Sr, Ba, Rb, Li, Na, and Ni. [0010] In an exemplary embodiment, obtaining an exemplary second solution may include mixing an exemplary inorganic metal halide solution, an exemplary organic amine halide solution, and an exemplary doping metal halide solution such that a ratio of an exemplary doping metal halide solution to an exemplary inorganic metal halide solution may be in a range of 0.1 to 0.9.

[0011] In an exemplary embodiment, obtaining an exemplary second solution may include mixing an exemplary inorganic metal halide solution, an exemplary organic amine halide solution, and an exemplary doping metal halide solution such that a molar ratio of an exemplary organic amine halide to (inorganic metal halide + doping metal halide) may be in a range of 1:2.5 to 1:3.5.

[0012] In an exemplary embodiment, obtaining the first solution may include dissolving a polymer such as polyvinylpyrrolidone, polyvinylidene difluoride, polyvinylidene difluoride copolymers, polyvinyl acetate, cellulose acetate, clickable nucleic acids, polysulfones, poly amide, poly imide, polycarbonates, or polystyrene in an exemplary first organic solvent.

[0013] In an exemplary embodiment, obtaining an exemplary first solution may include dissolving an exemplary polymer in a first organic solvent such as N,N-dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, N-methyl pyrrolidone, or dimethylacetamide. In an exemplary embodiment, obtaining an exemplary first solution may include dissolving polyvinylpyrrolidone in dimethyl sulfoxide.

[0014] In an exemplary embodiment, obtaining an exemplary second solution may further include obtaining an exemplary inorganic metal halide solution by mixing an inorganic metal halide powder with dimethyl sulfoxide, obtaining an exemplary organic amine halide solution by mixing an organic amine halide powder with dimethyl sulfoxide at room temperature, and obtaining an exemplary doping metal halide solution by mixing a doping metal halide with dimethyl sulfoxide.

[0015] In an exemplary embodiment, obtaining an exemplary inorganic metal halide solution may further include mixing an exemplary inorganic metal halide powder with dimethyl sulfoxide at a temperature in a range of 20 °C to 90 °C.

[0016] In an exemplary embodiment, obtaining an exemplary doping metal halide solution further may include mixing an exemplary doping metal halide with dimethyl sulfoxide at a temperature in a range of 20 °C to 60 °C. [0017] In an exemplary embodiment, obtaining an exemplary second solution may include dissolving an inorganic metal halide powder, an organic amine halide powder, and a doping metal halide powder all at once in dimethyl sulfoxide at room temperature.

[0018] In an exemplary embodiment, mixing an exemplary first solution and an exemplary second solution may include obtaining a mixture by mixing an exemplary first solution and an exemplary second solution, where an exemplary mixture may include 13 to 36 vol.% of polyvinylpyrrolidone .

[0019] In an exemplary embodiment, an exemplary target substrate may include at least one of glass, polymer, metal, paper, textile, and optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The novel features which are believed to be characteristic of the present disclosure, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a present exemplary embodiment of the present disclosure will now be illustrated by way of example. It is expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the present disclosure. Embodiments of the present disclosure will now be described by way of example in association with the accompanying drawings in which:

[0021] FIG. 1 illustrates a flowchart of a method for in-situ synthesis of dual-emission perovskite quantum dots, consistent with one or more exemplary embodiments of the present disclosure;

[0022] FIG. 2 illustrates X-ray diffraction spectra of the synthesized perovskite quantum dots for different concentrations of manganese, consistent with one or more exemplary embodiments of the present disclosure;

[0023] FIGs. 3A-3C illustrate scanning electron microscope images of layers of synthesized perovskite nanocrystals doped with different amounts of manganese, consistent with one or more exemplary embodiments of the present disclosure;

[0024] FIG. 4 illustrates absorption diagrams of synthesized perovskite nanocrystals doped with different amounts of manganese, consistent with one or more exemplary embodiments of the present disclosure; and [0025] FIG. 5 illustrates photoluminescent intensity graphs for synthesized perovskite nanocrystals doped with different amounts of manganese, consistent with one or more exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION

[0026] The novel features which are believed to be characteristic of the present disclosure, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following discussion.

[0027] The present disclosure is directed to exemplary embodiments of a method for in-situ synthesis of dual-emission perovskite quantum dots. An exemplary halide perovskite material generally has a formula of ABX3, where A may be an organic cation such as CH3NH3⁺(MA) and CH(NH2)²⁺(FA) or an alkali metal such as Cs. B may be a bivalent metal cation such as Pb²⁺, Sn²⁺, or Cu²⁺ and X may be an anion such as CT, Br“, or T. An exemplary solution method may be used to synthesize an exemplary halide perovskite material in bulk, layer, or crystal nanoparticle form. The emission spectrum of an exemplary halide perovskite material may be different based on the type of anion and cation utilized in the composition. For example, an exemplary chloride perovskite material may have an emission spectrum in blue region and an exemplary bromide perovskite material may have an emission spectrum in green region. A wide range of photoluminescent emissions within the visible region may be obtained by adjusting the stoichiometry of halogens within an exemplary halide perovskite material. Since each halogen has a specific sensitivity towards one type of gas, it may be possible to measure a wide variety of gases by adjusting the halogen of an exemplary halide perovskite material. Furthermore, by introducing a metal impurity, such as manganese to an exemplary halide perovskite material, the sensitivity of an exemplary halide perovskite material may be improved towards a specific type of gas. For example, introducing manganese impurity may lead to an increased sensitivity of an exemplary halide perovskite material towards oxygen.

[0028] Photoluminescent intensity in gas sensors based on the quenching of the luminescence of a halide perovskite material in the presence of a particular gas may depend on other parameters beside gas concentration, such as temperature, light intensity, and sensor position. Particularly, in addition to oxygen concentration, temperature strongly influences the measurement since both the luminescence and the quenching phenomena are temperature dependent. To remove these effects that cause inaccuracy in the sensor response, an inert reference fluorophore emission at a different wavelength is often used. Two techniques may be utilized for creating an internal referencing halide perovskite material. The first technique involves introducing a second signal as a reference, which is target sensitive. The second technique involves utilizing two target- sensitive signals that exhibit opposite responses, which may be achieved by synthesizing dual-emission perovskite materials.

[0029] There are two approaches for fabricating dual-emission fluorophores. A first approach may be forming the dual-emission structure by utilizing two luminophore materials such as the materials with core/shell structure and embedded nanocry stals-organic dyes. In a second approach, an intrinsically dual-emission fluorophore material may be utilized, such as doped nanocrystals and organic dyes. Utilizing an exemplary single fluorophore with dual-emission may allow for the development of a simplified radiometric gas-sensitive probes. In comparison with the organic and inorganic dye-based dual-emission fluorophore materials, doped- nanocrystal dual-emission fluorophores may exhibit broader absorption spectra and narrower emission peaks. Besides, doped-nanocrystal-based dual-emission fluorophores may have a high photoluminescent quantum yield, long-term photostability, tunable emission, low cost, and easy fabrication.

[0030] An exemplary dual-emission perovskite material may be fabricated by adding a metal impurity, such as manganese to the structure of an exemplary perovskite nanocrystal. This way, in addition to an intrinsic photoluminescent emission of an exemplary perovskite material, a new emission due to the presence of manganese ions will be generated in the structure of an exemplary perovskite material. In other words, the addition of a metal impurity such as manganese may create dual emissions, one of which may be utilized as an internal reference. [0031] An exemplary dual-emission perovskite material may be deposited as a sensor layer onto a target substrate. To this end, an exemplary dual-emission perovskite material may be generated in-situ by storing a perovskite precursor composition within a portable container and then spraying an exemplary perovskite precursor composition onto a desired substrate in different ambient conditions. An exemplary perovskite precursor composition may be engineered such that by depositing an exemplary perovskite precursor composition onto a target substrate, a layer of an exemplary dual-emission perovskite material may be formed on an exemplary target substrate in a uniform and cluster-free manner in different ambient temperature and humidity conditions. [0032] An exemplary perovskite precursor may include a polymer solution mixed with a second solution that may contain an inorganic metal halide solution, an organic amine halide solution, and a doping metal halide solution mixed together with specific ratios. An exemplary composition of an exemplary perovskite precursor may be designed so that a layer of an exemplary dual-emission perovskite quantum dots may be synthesized in-situ by simply spraying an exemplary perovskite precursor onto a dry target substrate. An exemplary in-situ formation of such layer of an exemplary dual-emission perovskite quantum dots may be independent of the type of substrate and an exemplary target substrate may be made of glass, paper, polymers, metals, etc.

[0033] An exemplary precursor for in-situ synthesis of an exemplary dual-emission perovskite material or exemplary dual-emission perovskite quantum dots may include an inorganic metal halide with a formula of YX2, in which Y may be Cu, Pb, Sn, or Ge. The X within the structure of an exemplary inorganic metal halide may be Cl, which creates a d transition and is suitable for dual emission. When I, Br, or SCN is added to Cl, emission quality may be improved due to the improvement of crystallization in the presence of added , Br, or SCN.

[0034] An exemplary precursor for in-situ synthesis of an exemplary dual-emission perovskite material or exemplary dual-emission perovskite quantum dots may further include a doped impurity that may have various functionalities. For example, a doped impurity may be utilized for optoelectronic performance control, light conversion, crystal growth control or structural stability control. Each specific functionality may be created by choosing a particular doping metal impurity. In order to synthesize exemplary dual-emission perovskite quantum dots, a metal impurity may be doped into the structure of exemplary dual-emission perovskite quantum dots that may allow for light conversion function within the structure of exemplary dual-emission perovskite quantum dots. To create dual emission, a doping metal such as Mn, Eu, Er, Yb, Dy, Tb, Sm, Ce, or Zn may be selected. Although, other doped metal elements, such as Bi, Cd, Al, Ca, Mg, K, Sb, In, Sr, Ba, Rb, Li, Na, or Ni may also be added to the structure in the presence or absence of dual-emission inducing metal impurities to improve optoelectronic properties, crystal growth, and stability. Needless to say, that a metal impurity such as manganese, when introduced into the structure of exemplary dual-emission perovskite quantum dots may have more than one function. Specifically, a metal impurity such as manganese not only adds light conversion functionality to exemplary perovskite quantum dots but also may improve the stability of exemplary dual-emission perovskite quantum dots. In another example, a metal impurity such as Zn may add a light conversion functionality within exemplary dual-emission perovskite quantum dots besides being a control agent for crystal growth.

[0035] FIG. 1 illustrates a flowchart of a method 100 for in-situ synthesis of dual-emission perovskite quantum dots, consistent with one or more exemplary embodiments of the present disclosure. In an exemplary embodiment, method 100 may include a step 102 of forming a precursor solution and a step 104 of spraying the formed precursor solution onto a target substrate. In an exemplary embodiment, step 102 of forming the precursor solution may include a step 106 of obtaining a first solution by dissolving a polymer in a first organic solvent, a step 108 of obtaining a second solution by mixing an inorganic metal halide solution, an organic amine halide solution, and a doping metal halide solution, and a step 110 of mixing the first solution and the second solution.

[0036] In an exemplary embodiment, step 106 of obtaining the first solution may include dissolving a polymer in the first organic solvent, where the polymer may be at least one of polyvinylpyrrolidone, poly vinylidene difluoride, poly vinylidene difluoride copolymers, polyvinyl acetate, cellulose acetate, clickable nucleic acids, polysulfones, poly amide, poly imide, polycarbonates, and polystyrene. In an exemplary embodiment, the first organic solvent may be at least one of N,N-dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, N-methyl pyrrolidone, and dimethylacetamide. For example, step 106 of obtaining the first solution may include dissolving a polymer such as polyvinylpyrrolidone in an organic solvent, such as dimethyl sulfoxide.

[0037] In an exemplary embodiment, step 106 of dissolving a polymer in the first organic solvent may include mixing the polymer with the first organic solvent utilizing a mixer, such as a magnetic stirrer. In an exemplary embodiment, dissolving a polymer in a first organic solvent may include mixing the polymer powder with the first organic solvent and stirring the mixture at room temperature for a predetermined amount of time, for example 24 hr. In an exemplary embodiment, the polymer may be PVP due to its superior transparency in comparison with other similar polymers. Specifically, PVP, among other advantageous properties, has the same solvent system as the precursor materials for perovskite quantum dots, excellent piezoelectric properties, dielectric properties, and mechanical properties. In an exemplary embodiment, the first solution may have a concentration between 100 and 300 mg/ml. [0038] In an exemplary embodiment, step 108 may include obtaining the second solution by mixing an inorganic metal halide solution, an organic amine halide solution, and a doping metal halide solution. An exemplary inorganic metal halide solution may be prepared by dissolving an inorganic metal halide powder in a second organic solvent. An exemplary organic amine halide solution may be prepared by dissolving an organic amine halide in the second organic solvent. An exemplary doping metal halide solution may be prepared by dissolving a doping metal halide in the second organic solvent. In an exemplary embodiment, an exemplary second organic solvent may be miscible with an exemplary first organic solvent. For example, an exemplary second organic solvent may be at least one of N,N-dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, and N-methyl pyrrolidone. In an exemplary embodiment, the first organic solvent and the second organic solvent may be similar.

[0039] In an exemplary embodiment, an exemplary inorganic metal halide solution may include an inorganic metal chloride with a formula of YCh and a second inorganic metal halide with a formula of YX2, where X may be at least one of I, Br, and SCN, and Y comprising at least one of Cu, Pb, Sn, and Ge. In an exemplary embodiment, an exemplary inorganic metal halide solution may include an inorganic metal halide chloride and a second inorganic metal halide, where a molar ratio of the second inorganic metal halide to the inorganic metal halide chloride may be in a range of 0.1 to 0.5.

[0040] In an exemplary embodiment, an exemplary organic amine halide solution may be prepared by dissolving an organic amine halide, such as CHsNHsBr, CH3NH3CI, or CH3NH3I in the second organic solvent that may be one of N,N-dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, and N-methyl pyrrolidone. In an exemplary embodiment, an exemplary organic amine halide solution may have a concentration between 1.25 and 2.5 M.

[0041] In an exemplary embodiment, an exemplary inorganic metal halide solution may be prepared by dissolving an inorganic metal halide, such as PbBn, PbCb, Pbb, SnBn, SnCh, or SnL in the second organic solvent that may be one of N,N-dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, and N-methyl pyrrolidone. In an exemplary embodiment, an exemplary inorganic metal halide solution may have a concentration between 1 and 1.2M. In an exemplary embodiment, an exemplary inorganic metal halide solution may be prepared by mixing the inorganic metal halide powder with dimethyl sulfoxide at a temperature in a range of 20 °C to 90 °C.

[0042] In an exemplary embodiment, an exemplary doping metal halide solution may include a doping metal that may be at least one of Mn, Eu, Er, Yb, Dy, Tb, Sm, Ce, and Zn. In an exemplary embodiment, an exemplary doping metal halide solution may further include a doping metal element that may be at least one of Bi, Cd, Al, Ca, Mg, K, Sb, In, Sr, Ba, Rb, Li, Na, and Ni. In an exemplary embodiment, an exemplary doping metal halide solution may be prepared by mixing the doping metal halide with dimethyl sulfoxide at a temperature in a range of 20 °C to 60 °C.

[0043] In an exemplary embodiment, step 108 may include obtaining the second solution by separately preparing the inorganic metal halide solution, the organic amine halide solution, and the doping metal halide solution, and then mixing the inorganic metal halide solution, the organic amine halide solution, and the doping metal halide solution. In an exemplary embodiment, step 108 may include obtaining the second solution by dissolving an inorganic metal halide powder, an organic amine halide powder, and a doping metal halide powder all at once in the second organic solvent at room temperature.

[0044] In an exemplary embodiment, step 108 may include obtaining the second solution by mixing the inorganic metal halide solution, the organic amine halide solution, and the doping metal halide solution such that a molar ratio of the organic amine halide to (inorganic metal halide + doping metal halide) may be in a range of 1:2.5 to 1:3.5. In an exemplary embodiment, step 108 may include mixing the inorganic metal halide solution, the organic amine halide solution, and the doping metal halide solution such that a molar ratio of the doping metal halide solution to the inorganic metal halide solution may be in a range of 0.1 to 0.9.

[0045] In an exemplary embodiment, step 110 may include mixing the first solution and the second solution. In an exemplary embodiment, the first solution and the second solution may be mixed to obtain a uniform organic solvent system, due to the fact that the first organic solvent and the second organic solvent may be selected such that the second organic solvent may be miscible with the first organic solvent. In other words, when the first organic solvent and the second organic solvent are mixed, no phase separation occurs within the system. Therefore, the solubility of an exemplary metal halide, an exemplary organic amine halide, and an exemplary polymer that may be dissolved in the first solution and the second solution may not be significantly different in the first organic solvent and the second organic solvent. In an exemplary embodiment, the first organic solvent and the second organic solvent may be similar.

[0046] In an exemplary embodiment, step 110 may include mixing the first solution and the second solution such that a concentration of the polymer within the obtained mixture of the first solution and the second solution may be between 13 to 36 vol.%. In an exemplary embodiment, step 110 may include mixing the first solution and the second solution at a temperature in a range of 25 °C to 70 °C.

[0047] In an exemplary embodiment, step 104 may include spraying the formed precursor solution onto a target substrate that may be at least one of glass, polymer, metal, paper, textile, and optical fiber. In other words, step 104 may involve in-situ formation of a thin layer of dual emission perovskite quantum dots on the target surface by transferring the prepared precursor solution onto the target substrate by spraying the prepared precursor solution onto the target substrate. In an exemplary embodiment, spraying the prepared precursor solution onto the target substrate may be carried out utilizing a user-friendly device, such as a hand-held spray can. In other words, the prepared precursor solution may be disposed within a hand-held spray can or any other spraying device and then may be easily sprayed onto a desired substrate.

EXAMPLE

[0048] In this example, dual-emission perovskite quantum dots were synthesized by utilizing an exemplary method similar to method 100. Here, a first polymer solution containing a IM polyvinylpyrrolidone solution was mixed with a second solution including PbBn, PbCh, MnCh, and methylammonium chloride to obtain a precursor solution that may be sprayed on any desired substrate to create a layer of dual-emission perovskite quantum dots on an exemplary target substrate.

[0049] A first solution was obtained by dissolving 200 mg of polyvinylpyrrolidone in 1 mL of a 1 M anhydrous dimethyl sulfoxide solution. Specifically, 200 mg of polyvinylpyrrolidone was added to 1 mL of 1 M anhydrous dimethyl sulfoxide solution and was stirred at a temperature of approximately 20-90 °C and for a period of approximately 1 hour.

[0050] A second solution may be prepared either by a three-step method or a single-step method. As mentioned before, a second solution may be obtained by mixing PbBn, PbCh, MnCh, and methylammonium chloride such that a molar ratio of PbBn to PbCh may be in a range of 0.1 to 0.5 and a molar ratio of MnCh to (PbBn + PbCh) may be in a range of 0.1 to 0.9. In this example, the second solution was prepared such that a molar ratio of PbBn to PbCh was 1 M and a molar ratio of MnCh to (PbBn + PbCh) was 1 to 9.

[0051] Specifically, in a three-step method, 367 mg of PbBn powder was mixed with dimethyl sulfoxide at a temperature of approximately 90 °C for half an hour on a magnetic stirrer to obtain a PbBn solution. Then, 278 mg of PbCh powder was mixed with dimethyl sulfoxide for an hour on a magnetic stirrer to obtain a PbCh solution. A IM methylammonium chloride solution was prepared by dissolving 67.25 mg of methylammonium chloride in 1000 pL of dimethyl sulfoxide solution. To this end, methylammonium chloride powder was added to dimethyl sulfoxide solution on a magnetic stirrer and the mixture was stirred for at least 3 minutes to ensure a complete dissolution of methylammonium chloride powder into dimethyl sulfoxide solution. Finally, 126 mg of MnChAFhO powder was dissolved into 1 mL of dimethyl sulfoxide solution by stirring a mixture of MnChAFhO powder and dimethyl sulfoxide solution on a magnetic stirrer at a temperature of approximately 60 °C for 10 minutes. [0052] A one-step approach may also be used for preparing an exemplary second solution. In this example, the second solution may also be prepared by dissolving 202.5 mg of methylammonium chloride powder, 278 mg of PbCh powder, 126 mg of MnCh powder, and 367 mg of PbBr2 powder in 7 mL of a dimethyl sulfoxide solution. To this end, all the aforementioned powders may be added to dimethyl sulfoxide solution and the resulting mixture may be stirred on a magnetic stirrer for at least 10 minutes at room temperature to obtain a homogeneous second solution. In this one-step approach there is no need for heating the solution and dissolution time is much shorter in comparison with the three-step approach.

[0053] In this example, the first polymer solution was added to the second solution with different volume percentages of 13, 19, 27, 29.25, 31.5, and 36% to prepare different perovskite precursor solutions. Here, the prepared precursor solution may be sprayed on different substrates without the need for heating the substrates and without any dependence on ambient temperature or humidity. As mentioned before, the prepared precursor may simply be stored in a portable container and be sprayed over any desired substrate to form a layer of dual-emission perovskite quantum dots.

[0054] An exemplary method for in-situ synthesis of dual-emission perovskite quantum dots may allow for simultaneous synthesis and doping of perovskite quantum dots. In other words, doping exemplary perovskite quantum dots with manganese and forming a uniform layer of exemplary perovskite quantum dots is carried out simultaneously. Such capability may be at least partially due to designing an exemplary perovskite precursor solution, in which a molar ratio of the organic amine halide to (inorganic metal halide + doping metal halide) is in a range of 1:2.5 to 1:3.5. An exemplary method for in-situ synthesis of dual-emission perovskite quantum dots may further allow for depositing a layer of perovskite quantum dots on a target substrate in a wide range of temperature between 20 °C and 90 °C and consequently there is no need for heating an exemplary target substrate before a layer of perovskite quantum dots may be deposited on an exemplary target substrate. Furthermore, utilizing an exemplary method for in-situ synthesis of dual-emission perovskite quantum dots, a uniform layer may be formed on a target substrate in an ambient with a relative humidity in a range of 10 to 70 percent.

[0055] FIG. 2 illustrates X-ray diffraction spectra (202-210) of the synthesized perovskite quantum dots for different concentrations of manganese, consistent with one or more exemplary embodiments of the present disclosure. X-ray diffraction spectrum 202 relates to a perovskite quantum dots sample without the addition of manganese, X-ray diffraction spectrum 204 relates to a perovskite quantum dots sample with Mn to Pb ratio of 2 to 8, X-ray diffraction spectrum 206 relates to a perovskite quantum dots sample with Mn to Pb ratio of 4 to 6, X-ray diffraction spectrum 208 relates to a perovskite quantum dots sample with Mn to Pb ratio of 8 to 2, and X-ray diffraction spectrum 210 relates to a perovskite quantum dots sample with Mn to Pb ratio of 9 to 1. As evident in FIG. 2, by introducing the manganese and with an increase in Mn to Pb ratio within the structure of synthesized perovskite quantum dots, reference peak (A29=0.1) shifts towards higher angles. The increase in the angle is indicative of replacement of Pb by Mn in the structure.

[0056] FIGs. 3A-3C illustrate scanning electron microscope images of layers of synthesized perovskite nanocrystals doped with different amounts of manganese, consistent with one or more exemplary embodiments of the present disclosure. FIG. 3A illustrates scanning electron microscope image of a layer of synthesized perovskite nanocrystals doped with 40% (0.133 M second solution) manganese, FIG. 3B illustrates scanning electron microscope image of a layer of synthesized perovskite nanocrystals doped with 80% (0.267 M second solution) manganese, and FIG. 3C illustrates scanning electron microscope image of a layer of synthesized perovskite nanocrystals doped with 90% (0.300 M second solution) manganese. Referring to FIGs. 3A-3C, it is evident that by increasing the percentage of manganese within the structure of synthesized perovskite quantum dots, the uniformity of the formed layer of the perovskite quantum dots increases.

[0057] FIG. 4 illustrates absorption diagrams of synthesized perovskite nanocrystals doped with different amounts of manganese, consistent with one or more exemplary embodiments of the present disclosure. Absorption diagram 402 relates to a perovskite quantum dots sample without the addition of manganese, absorption diagram 406 relates to a perovskite quantum dots sample with Mn to Pb ratio of 4 to 6, absorption diagram 408 relates to a perovskite quantum dots sample with Mn to Pb ratio of 8 to 2, and absorption diagram 410 relates to a perovskite quantum dots sample with Mn to Pb ratio of 9 to 1. It is evident that by increasing the concentration of doped manganese within the structure of synthesized perovskite nanocrystals, the energy band has shifted towards lower energies, which in turn is another evidence of manganese having been doped in the structure.

[0058] FIG. 5 illustrates photoluminescent intensity graphs for synthesized perovskite nanocrystals doped with different amounts of manganese, consistent with one or more exemplary embodiments of the present disclosure. Photoluminescent intensity graph 402 relates to a perovskite quantum dots sample without the addition of manganese, photoluminescent intensity graph 406 relates to a perovskite quantum dots sample with Mn to Pb ratio of 4 to 6 photoluminescent intensity graph 408 relates to a perovskite quantum dots sample with Mn to Pb ratio of 8 to 2, and photoluminescent intensity graph 410 relates to a perovskite quantum dots sample with Mn to Pb ratio of 9 to 1. It is evident that by increasing the concentration of doped manganese within the structure of synthesized perovskite quantum dots, the phosphorescence intensity of manganese increases, and the fluorescence intensity of perovskite decreases.

[0059] The foregoing description of the specific embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. [0100] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the following claims and their equivalents.

[0101] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not to the exclusion of any other integer or step or group of integers or steps.

Moreover, the word "substantially" when used with an adjective or adverb is intended to enhance the scope of the particular characteristic, e.g., substantially planar is intended to mean planar, nearly planar and/or exhibiting characteristics associated with a planar element. Further use of relative terms such as “vertical”, “horizontal”, “up”, “down”, and “side-to-side” are used in a relative sense to the normal orientation of the apparatus.

Claims

WHAT IS CLAIMED IS:

1. A method for in-situ synthesis of dual-emission perovskite quantum dots, the method comprising: forming a precursor solution by: obtaining a first solution by dissolving a polymer in a first organic solvent; obtaining a second solution by mixing an inorganic metal halide solution, an organic amine halide solution, and a doping metal halide solution; and mixing the first solution and the second solution; and spraying the precursor solution onto a target substrate.

2. The method of claim 1, wherein the inorganic metal halide solution comprises an inorganic metal chloride with a formula of YCh and a second inorganic metal halide with a formula of YX2, X comprising at least one of I, Br, and SCN, and Y comprising at least one of Cu, Pb, Sn, and Ge.

3. The method of claim 2, wherein the inorganic metal halide solution comprises the inorganic metal halide chloride and the second inorganic metal halide with a molar ratio of the second inorganic metal halide to the inorganic metal halide chloride in a range of 0.1 to 0.5.

4. The method of claim 2, wherein the doping metal halide solution comprises a doping metal selected from the group consisting of Mn, Eu, Er, Yb, Dy, Tb, Sm, Ce, and Zn.

5. The method of claim 4, wherein the doping metal halide solution further comprises a doping metal element selected from the group consisting of Bi, Cd, Al, Ca, Mg, K, Sb, In, Sr, Ba, Rb, Li, Na, and Ni.

6. The method of claim 4, wherein obtaining the second solution comprises mixing the inorganic metal halide solution, the organic amine halide solution, and the doping metal halide solution with a ratio of the doping metal halide solution to the inorganic metal halide solution being in a range of 0.1 to 0.9. The method of claim 1, wherein obtaining the second solution comprises mixing the inorganic metal halide solution, the organic amine halide solution, and the doping metal halide solution with a molar ratio of the organic amine halide to (inorganic metal halide + doping metal halide) being in a range of 1:2.5 to 1:3.5. The method of claim 7, wherein obtaining the first solution comprises dissolving a polymer selected from the group consisting of polyvinylpyrrolidone, polyvinylidene difluoride, polyvinylidene difluoride copolymers, polyvinyl acetate, cellulose acetate, clickable nucleic acids, polysulfones, poly amide, poly imide, polycarbonates, and polystyrene in the first organic solvent. The method of claim 8, wherein obtaining the first solution comprises dissolving the polymer in a first organic solvent selected from the group consisting of N,N- dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, N-methyl pyrrolidone, and dimethylacetamide. The method of claim 8, wherein obtaining the first solution comprises dissolving polyvinylpyrrolidone in dimethyl sulfoxide. The method of claim 1, wherein obtaining the second solution further comprises: obtaining the inorganic metal halide solution by mixing an inorganic metal halide powder with dimethyl sulfoxide; obtaining the organic amine halide solution by mixing an organic amine halide powder with dimethyl sulfoxide at room temperature; and obtaining the doping metal halide solution by mixing a doping metal halide with dimethyl sulfoxide. The method of claim 11, wherein obtaining the inorganic metal halide solution further comprises mixing the inorganic metal halide powder with dimethyl sulfoxide at a temperature in a range of 20 °C to 90 °C. The method of claim 11, wherein obtaining the doping metal halide solution further comprises mixing the doping metal halide with dimethyl sulfoxide at a temperature in a range of 20 °C to 60 °C. The method of claim 1, wherein obtaining the second solution comprises dissolving an inorganic metal halide powder, an organic amine halide powder, and a doping metal halide powder all at once in dimethyl sulfoxide at room temperature. The method of claim 1, wherein mixing the first solution and the second solution comprises obtaining a mixture by mixing the first solution and the second solution, the mixture comprising 13 to 36 vol.% of polyvinylpyrrolidone. The method of claim 1, wherein the target substrate comprises at least one of glass, polymer, metal, paper, textile, and optical fiber.

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