Method for manufacturing perovskite nanocrystals by using cold-injection method, and perovskite light-emitting device comprising perovskite nanocrystals manufactured thereby

Abstract

The present invention relates to a method for manufacturing perovskite nanocrystals having excellent photoluminescence efficiency and capable of realizing pure colors according to the Rec. 2100 (or Rec. 2020) standard, and a light-emitting device comprising the perovskite nanocrystals manufactured thereby.

Description

Method for producing perovskite nanocrystals using low-temperature injection method and perovskite light-emitting device including perovskite nanocrystals produced thereby

[0001] The present invention relates to a method for producing perovskite nanocrystals with controlled defects using a cold-injection method, and to a light-emitting device comprising the perovskite nanocrystals produced thereby. The present invention claims the benefit of Korean Patent Application No. 10-2023-0182185, filed with the Korean Intellectual Property Office on December 14, 2023, the entire contents of which are incorporated herein by reference.

[0002] Metal halide-based perovskite nanocrystals (PeNCs) are being actively studied as next-generation display materials due to their characteristics such as high light absorption, excellent luminescence, and narrow full width at half maximum of the emission spectrum. Perovskite light-emitting devices (PeLEDs) have high color purity, can precisely control the emission wavelength depending on the halide composition ratio, and have a low manufacturing cost due to their solution-based manufacturing process, so they are attracting attention as strong candidates in the field of next-generation high-resolution displays to replace OLEDs and QLEDs.

[0003] Representative methods for synthesizing perovskite nanocrystals include high-temperature / inert condition synthesis such as the hot-injection method, and room-temperature / atmospheric condition synthesis such as the ligand-assisted reprecipitation (LARP) method described in non-patent references 1 and 2 and the emulsion synthesis method described in non-patent reference 3. Although high-temperature / inert condition synthesis can synthesize high-performance perovskite nanocrystals, this method requires high temperatures of 150°C or higher, an inert gas environment such as a nitrogen atmosphere, and equipment for synthesis such as a shrink line, and it takes a relatively long synthesis time, which has limitations in terms of mass production and process cost. Although the existing room-temperature / atmospheric condition synthesis can improve this limitation in process cost, it is difficult to produce high-performance and highly reproducible perovskite nanocrystals.

[0004] Meanwhile, the CsPbBr3 (Caesium lead bromide) light-emitting material, which has been mainly reported in the field of perovskite nanocrystals, is not suitable for commercialization because its emission wavelength does not meet the Rec. 2100 standard (or Rec. 2020 standard). Rec. 2100 is a color standard for 4K / UHD recommended by the ITU, an international broadcasting standards organization, and is also called BT2100.

[0005] Accordingly, there is a need for a manufacturing method capable of mass-producing high-performance perovskite nanocrystals that are compliant with Rec. 2100 standards, have high photoluminescence quantum yield (PLQY), and satisfy high color purity, high stability, and high crystallinity.

[0006] The effects of synthesis conditions on the properties of perovskite nanocrystals have been studied, and representative studies have been conducted on the effects of synthesis temperature on perovskite nanocrystals. Non-patent reference 4, which discloses room temperature / low temperature synthesis of perovskite nanocrystals, discloses synthesizing perovskite nanocrystals by dissolving a perovskite precursor compound and a ligand in the same polar solvent and then injecting this into a non-polar solvent that does not contain a ligand, and observed the characteristics of the perovskite nanocrystals that change depending on the synthesis temperature. In the case of the perovskite nanocrystals obtained through this method, as the synthesis temperature decreases, the PLQY decreases from 93% (synthesis temperature 60 ℃) to 74% (synthesis temperature 0 ℃), and the emission wavelength shifts to a shorter wavelength band of 520 nm (synthesis temperature 60 ℃) to 475 nm (synthesis temperature 0 ℃), and at the same time, the half width of the spectrum increases, and a high-efficiency light-emitting body suitable for the Rec. 2100 standard could not be realized. Another prior non-patent document 5 that analyzed the effect of synthesis temperature disclosed the synthesis of perovskite nanocrystals according to temperature by a synthesis method similar to prior non-patent document 4 in which a perovskite precursor compound and a ligand are dissolved in the same polar solvent, and in the case of the perovskite nanocrystals obtained as a result, as the synthesis temperature decreased, the PLQY increased from 20% (synthesis temperature 25 ℃) to 48% (synthesis temperature 3 ℃), and decreased to 36% (synthesis temperature -5 ℃) below that, and the emission wavelength shifted to a short wavelength from 523 nm (synthesis temperature 25 ℃) to 521 nm (synthesis temperature -5, 3 ℃), which also could not realize a high-efficiency light-emitting body suitable for the Rec. 2100 standard.In addition, if we compare the prior non-patent documents 4 and 5, we can see that the effects according to the synthesis temperature are different despite using similar synthesis methods. This confirms that the effect according to the synthesis temperature is not only unclear, but is also greatly affected by other synthesis conditions. In addition, the prior non-patent documents only reported the results of changes in optical properties according to temperature, and did not perform a specific analysis on the cause. As seen in these papers, there is a problem that the characteristics of the particles (crystallinity, emission wavelength, luminescence efficiency) deteriorate when the temperature is lowered to around 0℃ or below 0℃ (e.g., below 3℃). Therefore, since higher luminescence efficiency must be obtained without a significant change in the emission wavelength, the synthesis temperature has been mostly performed at room temperature (generally 20-25℃, but it can be lowered to about 10℃ depending on the country or region).

[0007] [Prior art literature]

[0008] (Patent Document 0001) US 10193088 B2

[0009] (Patent Document 0002) US 20200020834 A1

[0010] (Non-patent Document 0001) Zhang F, Zhong H, Chen C, Wu

[0011] (비특허문헌 0002) Kim YH, Wolf C, Kim YT, Cho H, Kwon W, Do S, Sadhanala A, Park CG, Rhee SW, Im SH, Friend RH, Lee TW, "Highly Efficient Light-Emitting Diodes of Colloidal Metal-Halide Perovskite Nanocrystals beyond Quantum Size" ACS Nano (ACS Publications), 2017.

[0012] (비특허문헌 0003) Kim YH, Lee GH, Kim YT, Wolf C, Yun HJ, Kwon W, Park CG, Lee TW, "High efficiency perovskite light-emitting diodes of ligand-engineered colloidal formamidinium lead bromide nanoparticles" Nano Energy (Elsevier), 2017.

[0013] (비특허문헌 0004) Huang H, Susha AS, Kershaw SV, Hung TF, Rogach AL, "Control of Emission Color of High Quantum Yield CH3NH3PbBr3 Perovskite Quantum Dots by Precipitation Temperature" Adv Sci (Weinh), 2015.

[0014] (Non-patent document 0005) Prochazkova AJ, Scharber MC, Yumusak C, Jancik J, Masilko J, Bruggemann O, Weiter M, Sariciftci NS, Krajcovic J, Salinas Y, Kovalenko A "Synthesis conditions influencing formation of MAPbBr3 perovskite nanoparticles prepared by the ligand-assisted precipitation method" Sci Rep (Springer Nature), 2020.

[0015] The technical problem to be achieved by the present invention is to provide a method for manufacturing perovskite nanocrystals, which can be performed under atmospheric conditions and can provide high-performance perovskite nanocrystals having a PLQY of 85% or more without significantly changing (shifting) the wavelength of the original inherent bulk material by less than 20 nm.

[0016] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0017] One embodiment of the present invention provides a method for producing perovskite nanocrystals, comprising the steps of: preparing a ligand solution containing an organic ligand, a demulsifier, and a non-polar solvent; preparing a precursor solution containing a perovskite precursor and a polar solvent; adding the precursor solution to the ligand solution; and stirring the ligand solution to which the precursor solution has been added, wherein the step of adding the precursor solution to the ligand solution is performed at a temperature of 15° C. or less, and the precursor solution contains a highly coordinated polyhalide metallate.

[0018] Another embodiment of the present invention provides a perovskite nanocrystal manufactured by a method according to an embodiment of the present invention.

[0019] Another embodiment of the present invention provides a perovskite light-emitting device comprising: a first electrode; a hole injection layer positioned on the first electrode; a light-emitting layer positioned on the hole injection layer and including perovskite nanocrystals manufactured by a method according to one embodiment of the present invention; an electron injection layer positioned on the light-emitting layer; and a second electrode positioned on the electron injection layer.

[0020] The method for manufacturing perovskite nanocrystals according to one embodiment of the present invention can provide perovskite nanocrystals having a photoluminescence efficiency (PLQY) close to 100%. This is the opposite result to that of non-patent literatures 4 and 5, where PLQY decreases as the synthesis temperature decreases to near or below 0 degrees (e.g., below 3 degrees), confirming that the synthesis mechanism is different.

[0021] The method for manufacturing perovskite nanocrystals according to one embodiment of the present invention can be performed under atmospheric conditions and can be easily mass-produced.

[0022] A perovskite light-emitting device according to one embodiment of the present invention can satisfy the Rec. 2100 standard and can have excellent color purity, luminous efficiency, and external quantum efficiency (EQE).

[0023] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and the attached drawings.

[0024] FIG. 1 is a drawing briefly showing a method for manufacturing perovskite nanocrystals according to one embodiment of the present invention.

[0025] Figure 2 is a flowchart of a method for manufacturing perovskite nanocrystals according to one embodiment of the present invention.

[0026] Figure 3 shows the results of UV-visible absorption analysis performed in Experimental Example 1.

[0027] Figure 4 is a diagram showing the conductivity (μS / cm) as a function of temperature of a ligand solution containing oleic acid and n-decylamine, a solution containing only oleic acid, and a solution containing only n-decylamine.

[0028] Figure 5 shows the temperature dependence of a solution containing oleic acid, n-decylamine, and perovskite precursor (PbBr2). 1 This is a diagram showing the results of H-NMR analysis.

[0029] Figure 6 is an XRD pattern for a film including perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0030] Figure 7 shows the solid state of perovskite nanocrystals manufactured in Example 1-1, Example 1-4, and Comparative Example 1-1. 1 This is a diagram showing the H MAS NMR spectrum.

[0031] FIG. 8 is a diagram showing the relative content ratios of carbon to lead (C / Pb), nitrogen to lead (N / Pb), and bromine to lead (Br / Pb) contained in perovskite nanocrystals manufactured in Examples 1-1, 1-4, and Comparative Example 1-1.

[0032] Figure 9 is a high-resolution scanning transmission electron microscope (HR-STEM) and fast Fourier transform (FFT) image of the perovskite nanocrystals manufactured in Example 1-1.

[0033] Figure 10 is a high-resolution (iDPC)-STEM image of the perovskite nanocrystal of Example 1-1 (a) and the perovskite nanocrystal of Comparative Example 1-1 (b) (scale bar represents 1 nm).

[0034] Figure 11 is a drawing showing the particle size distribution of perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0035] Figure 12 is a diagram showing the photoluminescence quantification (PLQY) measured for a solution (a) and a film (b) containing perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0036] Figure 13 is a diagram showing the photoluminescence quantification (PLQY) measured for a solution (a) and a film (b) containing perovskite nanocrystals manufactured in Examples 1-6 to 1-8.

[0037] Figure 14 is a diagram showing the photoluminescence spectrum (PL spectrum) for perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0038] Figure 15 is a diagram showing the photoluminescence efficiency and PL peak of perovskite nanocrystals previously reported in other studies and perovskite nanocrystals manufactured in Example 1-1.

[0039] Figure 16 is a diagram showing the photoluminescence spectra (a, b) measured in-situ in Example 1-1 and the photoluminescence spectra (c, d) measured in-situ in Comparative Example 1-1.

[0040] Figure 17 is an absorption spectrum measured in-situ at 5-minute intervals in Example 1-1(a) and Comparative Example 1-1(b).

[0041] Figure 18 is a drawing showing the photoluminescence efficiency measured in-situ for Example 1-1 and Comparative Example 1-1.

[0042] Figure 19 is a high-resolution scanning transmission electron microscope (HR-STEM) image of perovskite nanocrystals manufactured in Example 1-1(a) and Comparative Example 1-1(b).

[0043] Figure 20 is a diagram showing the photoluminescence lifetime (PL lifetime) of perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0044] Figure 21 is a diagram showing the photoluminescence spectrum of perovskite nanocrystals manufactured in Example 1-1(a) and Comparative Example 1-1(b) depending on the temperature.

[0045] Figure 22 is a diagram showing the integrated PL intensity and calculated exciton binding energy according to temperature of perovskite nanocrystals manufactured in Example 1-1 and Comparative Example 1-1.

[0046] Figure 23 shows the perovskite nanocrystals (FA) manufactured at scales of 15x, 30x, 60x, 150x and 1000x (10 L). 0.9 GA 0.1 This is a drawing showing the photoluminescence efficiency and luminescence photograph of a solution containing PbBr3) and an organic ligand surrounding it.

[0047] Figure 24 is a schematic diagram of a perovskite light-emitting device manufactured in Example 2.

[0048] Figure 25 is a diagram showing the electrical efficiency (a) and external quantum efficiency (b) according to voltage of the perovskite light-emitting device manufactured in Example 2 and Comparative Example 2.

[0049] Figure 26 is a diagram showing the external quantum efficiency distribution for 40 perovskite light-emitting devices manufactured by the method according to Example 2.

[0050] Figure 27 is a photograph showing the light emitting perovskite light emitting device manufactured in Example 2.

[0051] Figure 28 is a diagram showing the electroluminescence (EL) spectra of the perovskite light-emitting device manufactured in Example 2 at various operating voltages.

[0052] Figure 29 is a diagram showing the photoluminescence efficiency of manufactured perovskite nanocrystals according to the concentration of the precursor solution.

[0053] Figure 30 is a diagram showing the photoluminescence efficiency and photoluminescence peak wavelength measured in-situ while stirring the ligand solution to which the precursor solution was added in Experimental Example 10.

[0054] FIG. 31 is a diagram showing the luminescence spectrum (a) and photoluminescence efficiency (PLQY) (b) measured for a solution containing FAPbBr3 perovskite nanocrystals prepared in Examples 3-1, 3-2 and Comparative Example 3-1, and the luminescence spectrum (c) and photoluminescence efficiency (PLQY) (d) measured for a solution containing MAPbBr3 perovskite nanocrystals prepared in Examples 4-1, 4-2 and Comparative Example 4-1.

[0055] Figure 32 shows FA manufactured in Examples 5-1 to 5-4 and Comparative Examples 5-1 and 5-2. 0.9 Cs 0.1 PbBr 1.2 I 1.8 This is a diagram showing the luminescence spectrum (a) and photoluminescence quantum yield (PLQY) (b) measured for a solution containing perovskite nanocrystals.

[0056] Figure 33 shows FAPbCl prepared in Examples 6-1 to 6-4 and Comparative Examples 6-1 and 6-2. 1.2 Br 1.8 This is a diagram showing the luminescence spectrum (a) and photoluminescence quantum yield (PLQY) (b) measured for a solution containing perovskite nanocrystals.

[0057] Figure 34 is a drawing showing the luminescence spectrum (a) and photoluminescence efficiency (PLQY) (b) measured for a solution containing FAPbI3 perovskite nanocrystals manufactured in Examples 7-1 to 7-4 and Comparative Examples 7-1 and 7-2.

[0058] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0059] Throughout this specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0060] Throughout this specification, bulk material means a material having a large particle size, i.e., a particle diameter, ranging from approximately 100 nm to several mm.

[0061] Throughout this specification, “A and / or B” means “A and B, or A or B.”

[0062] Hereinafter, the present invention will be described in more detail.

[0063] One embodiment of the present invention provides a method for producing perovskite nanocrystals, comprising the steps of: preparing a ligand solution containing an organic ligand, a demulsifier, and a non-polar solvent; preparing a precursor solution containing a perovskite precursor and a polar solvent; adding the precursor solution to the ligand solution; and stirring the ligand solution to which the precursor solution has been added, wherein the step of adding the precursor solution to the ligand solution is performed at a temperature of 15° C. or less, and the precursor solution contains a highly coordinated polyhalide metallate.

[0064] According to one embodiment of the present invention, the high-coordination polyhalide metallate may be derived from a B site metal precursor, i.e., BX2.

[0065] More specifically, the polyhalide metallate can be formed by dissolving a B site metal precursor in a polar solvent, and the coordination number of the polyhalide metallate can vary depending on the total concentration and ratio of the perovskite precursor in the precursor solution.

[0066] The coordination number of the above polyhalide metallate can be confirmed by spectroscopic techniques such as UV-visible absorption analysis. For example, if the metal cation is Pb and the halide anion is Br, and the coordination number is 2 (PbBr2), it is 285 nm, and if it is 3 (PbBr3) - ) 310 nm, 4 in case of (PbBr4 2- ) is known to have an absorption peak at 360 nm, and it can be confirmed that the absorption spectrum shifts to a longer wavelength as the coordination number increases.

[0067] According to one embodiment of the present invention, the high-coordination polyhalide metallate may mean a coordination number of 3 or more, 4 or more, 5 or more, or 6.

[0068] For example, the above-mentioned highly coordinated polyhalide metallate is PbCl3 - , PbCl4 2- , PbCl5 3- , PbCl6 4- , PbBr 3- , PbBr4 2- , PbBr5 3- , PbBr6 4- , PbI 3- , PbI4 2- , PbI5 3- , PbI6 4- , MnCl3 - , MnCl4 2- , MnCl5 3- , MnCl6 4- , MnBr3 - , MnBr4 2- , MnBr5 3- , MnBr6 4- , MnI3 - , MnI4 2- , MnI5 3- , MnI6 4- , CuCl3 - , CuCl4 2- , CuCl5 3- , CuCl6 4-, CuBr3 - , CuBr4 2- , CuBr5 3- , CuBr6 4- , CuI3 - , CuI4 2- , CuI5 3- , CuI6 4- , GaCl3 - , GaCl4 2- , GaCl5 3- , GaCl6 4- , GaBr3 - , GaBr4 2- , GaBr5 3- , GaBr6 4- , GaI3 - , GaI4 2- , GaI5 3- , GaI6 4- , GeCl3 - , GeCl4 2- , GeCl5 3- , GeCl6 4- , GeBr3 - , GeBr4 2- , GeBr5 3- , GeBr6 4- , GeI3 - , GeI4 2- , GeI5 3- , GeI6 4- , InCl3 - , InCl4 2- , InCl5 3- , InCl6 4- , InBr3 - , InBr4 2- , InBr5 3- , InBr6 4- , InI3 - , InI4 2- , InI5 3- , InI6 4- , AlCl3 - , AlCl4 2- , AlCl5 3- , AlCl6 4- , AlBr3 - , AlBr4 2- , AlBr53- , AlBr6 4- , AlI3 - , AlI4 2- , AlI5 3- , AlI6 4- , SbCl3 - , SbCl4 2- , SbCl5 3- , SbCl6 4- , SbBr3 - , SbBr4 2- , SbBr5 3- , SbBr6 4- , SbI3 - , SbI4 2- , SbI5 3- , SbI6 4- , BiCl3 - , BiCl4 2- , BiCl5 3- , BiCl6 4- , BiBr3 - , BiBr4 2- , BiBr5 3- , BiBr6 4- , BiI3 - , BiI4 2- , BiI5 3- , BiI6 4- , PoCl3 - , PoCl4 2- , PoCl5 3- , PoCl6 4- , PoBr3 - , PoBr4 2- , PoBr5 3- , PoBr6 4- , PoI3 - , PoI4 2- , PoI5 3- , PoI6 4- , SnCl3 - , SnCl4 2- , SnCl5 3- , SnCl6 4- , SnBr3 - , SnBr4 2- , SnBr5 3- , SnBr6 4- , SnI3 - , SnI4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , SnI5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , SnI6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , EuCl3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , EuCl4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , EuCl5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , EuCl6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , EuBr3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , EuBr4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , EuBr5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , EuBr6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , EuI3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , EuI4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , EuI5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , EuI6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , YbCl3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , YbCl4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , YbCl5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , YbCl6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , YbBr3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , YbBr4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , YbBr5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , YbBr6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , YbI3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , YbI4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , YbI5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , YbI6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , NiCl3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , NiCl4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , NiCl5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , NiCl6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , NiBr3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , NiBr4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , NiBr5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , NiBr6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , NiI3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , NiI4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , NiI5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , NiI6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , CoCl3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , CoCl4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , CoCl5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , CoCl6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , CoBr3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , CoBr4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , CoBr5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , CoBr6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , CoI3<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> , CoI4<h2 style=";text-align:left;direction:ltr"> 2- <h2 style=";text-align:left;direction:ltr"> , CoI5<h2 style=";text-align:left;direction:ltr"> 3- <h2 style=";text-align:left;direction:ltr"> , CoI6<h2 style=";text-align:left;direction:ltr"> 4- <h2 style=";text-align:left;direction:ltr"> , FeCl3- , FeCl4 2- , FeCl5 3- , FeCl6 4- , FeBr3 - , FeBr4 2- , FeBr5 3- , FeBr6 4- , FeI3 - , FeI4 2- , FeI5 3- , FeI6 4- , CrCl3 - , CrCl4 2- , CrCl5 3- , CrCl6 4- , CrBr3 - , CrBr4 2- , CrBr5 3- , CrBr6 4- , CrI3 - , CrI4 2- , CrI5 3- , CrI6 4- , PdCl3 - , PdCl4 2- , PdCl5 3- , PdCl6 4- , PdBr3 - , PdBr4 2- , PdBr5 3- , PdBr6 4- , PdI3 - , PdI4 2- , PdI5 3- , PdI6 4- , CdCl3 - , CdCl4 2- , CdCl5 3- , CdCl6 4- , CdBr3 - , CdBr4 2- , CdBr5 3- , CdBr6 4- , CdI3 - , CdI4 2- , CdI5 3- , CdI6 4- , CaCl3 - , CaCl4 2- , CaCl5 3-, CaCl6 4- , CaBr3 - , CaBr4 2- , CaBr5 3- , CaBr6 4- , CaI3 - , CaI4 2- , CaI5 3- , CaI6 4- , SrCl3 - , SrCl4 2- , SrCl5 3- , SrCl6 4- , SrBr3 - , SrBr4 2- , SrBr5 3- , SrBr6 4- , SrI3 - , SrI4 2- , SrI5 3- and SrI6 4- It may include one or more of the following:

[0069] The method for producing perovskite nanocrystals of the present invention is characterized in that an organic ligand is not included in a precursor solution containing a perovskite precursor and a polar solvent, the organic ligand is included in a mixed solution of a nonpolar solvent and a demulsifier, and the step of adding the precursor solution to the ligand solution is performed at a temperature of 15°C or less. In addition, the method for producing perovskite nanocrystals of the present invention is characterized in that the concentration of the perovskite precursor included in the precursor solution is 0.1 M or more, which is higher than that of the existing LARP method.

[0070] In the conventional LARP process, the concentration of the perovskite precursor in the precursor solution is typically diluted to 0.1 M or less, no demulsifier is used, at least one component of the organic ligand or all of the organic ligand components are dissolved in a solution containing a polar solvent and a perovskite precursor to prepare the precursor, and the solution containing the perovskite precursor, the organic ligand, and the polar solvent is injected into a nonpolar solvent in which the perovskite precursor does not dissolve, thereby synthesizing perovskite nanocrystals through precipitation. The method for producing perovskite nanocrystals of the present invention is characterized in that, unlike the conventional LARP, a perovskite precursor solution that does not contain an organic ligand is prepared, and this is injected into a solution containing a nonpolar solvent, an organic ligand, and a demulsifier to produce perovskite nanocrystals.

[0071] When a polar solution containing a perovskite precursor and not containing an organic ligand is injected into a non-polar solvent, some perovskite nanocrystals are formed (mainly nanoplatelets) even if the two solvents are miscible, and in most cases, the precursor exists in a colloidal form. Therefore, in order to form perovskite nanocrystals according to the present synthesis method, a demulsifier must be included. Here, the demulsifier can increase the yield of perovskite nanoparticles by allowing the remaining perovskite precursor that cannot participate in crystallization to participate in the reaction, and can also assist in perovskite crystallization at cold temperatures, for example, below 4°C or below 3°C. The demulsifier can be a solvent such as alcohol used in emulsion synthesis.

[0072] In addition, the present invention is similar to the previously reported non-patent documents 4 and 5 in that the synthesis temperature is controlled, but in the manufacturing method of the present invention, the concentration of the perovskite precursor in the precursor solution is 8 times or more higher (0.6 M (present invention), 0.072 M (non-patent document 4), 0.057 M (non-patent document 5)), and unlike the prior documents in which the organic ligand is included in the precursor solution containing the perovskite precursor and a polar solvent, in the present invention, the perovskite precursor solution does not include the ligand, so that the interaction between the perovskite and the ligand can be blocked before the crystallization step of the perovskite nanocrystal.

[0073] The precursor solution and organic ligand are factors that significantly affect the synthesis mechanism, and the characteristics of the final crystal can differ significantly depending on the concentration of the precursor, the type and amount of the organic ligand injected, and the stage. Unlike the prior art, the present invention provides a method for producing perovskite nanocrystals with a different growth mechanism from the prior art by utilizing the change in the state of the ligand as the precursor solution has a high concentration of the perovskite precursor and the precursor solution is changed to not contain the organic ligand, and the temperature of the ligand solution is lowered to 15°C or lower, 10°C or lower, or 0°C or lower. In particular, when preparing each precursor solution and ligand solution in a situation where the interaction between the ligand and the perovskite is blocked, and then injecting the precursor solution into the ligand solution, the reaction is performed in a situation where the temperature of the reactor is lowered to 15°C or lower to induce the interaction, thereby enabling better control of the perovskite crystal growth.

[0074] The method for manufacturing perovskite nanocrystals according to the present invention may differ in its synthesis mechanism from the existing LARP and emulsion synthesis methods. In the case of the LARP synthesis method, such as in prior non-patent documents 1 and 2, a perovskite precursor solution in which a perovskite precursor is dissolved in a polar solvent (e.g., DMF) is injected into a non-polar solvent (e.g., toluene) that is miscible with polar solvents but in which the perovskite precursor does not dissolve, thereby forming perovskite nanocrystals through precipitation. In this case, immediately after synthesis, it can be confirmed that the entire solution emits a bright green glow when exposed to UV or blue light without any additional chemical treatment. In the case of an emulsion synthesis method such as the prior non-patent document 3, a perovskite precursor solution in which a perovskite precursor is dissolved in a polar solvent (e.g., DMF) is injected into a non-polar solvent (e.g., hexane) that does not mix with the polar solvent and in which the perovskite precursor does not dissolve, thereby forming an emulsion state, and then a demulsifier (e.g., tert-butanol) is added to form perovskite nanocrystals. In this case, after the perovskite precursor solution is added, a milky emulsion is formed until an additional demulsifier is injected, and it can be confirmed that the solution does not emit light when exposed to UV or blue light.

[0075] The method for manufacturing perovskite nanocrystals according to the present invention follows a pseudo-emulsion synthesis mechanism in which perovskite nanocrystals are hardly precipitated and mostly maintain a colloidal state even though a precursor solution is injected into a non-polar solvent (e.g., toluene) that is mixed with a polar solvent (e.g., DMF) of the precursor solution, and thus is not consistent with the mechanisms of existing LARP and emulsion synthesis methods. In addition, nanocrystals with increased crystallinity and luminescence efficiency can be synthesized even at temperatures near or below 0 degrees Celsius by following the pseudo-emulsion synthesis mechanism.

[0076] The quasi-emulsion state according to the above-mentioned quasi-emulsion synthesis mechanism is a state that temporarily exists immediately after adding (injecting) a precursor solution containing a perovskite precursor and a polar solvent that does not contain an organic ligand to a ligand solution containing an organic ligand, an anti-emulsifier, and a non-polar solvent, or after the addition and before complete stirring, and may mean that a part of the solution exists in a state similar to an emulsion. The solution in the quasi-emulsion state may have a relatively milky color and may exhibit a blue color when irradiated with UV or blue light.

[0077] Specifically, in the quasi-emulsion synthesis mechanism according to the present invention, as soon as a quasi-emulsion is formed when a precursor solution is added to a ligand solution, the quasi-emulsion can be broken by the anti-emulsifier included in the ligand solution.

[0078] In the above quasi-emulsion solution, a small amount of perovskite having a nanoplatelet crystal structure rather than the three-dimensional (3D) nanocrystals to be manufactured can be formed, and the formation of 3D nanocrystals can be induced as the quasi-emulsion is broken by the anti-emulsifier.

[0079] The mechanism by which a quasi-emulsion is formed by adding (injecting) a precursor solution to a ligand solution is determined by the total concentration of the perovskite precursor in the precursor solution and the precursor composition (e.g., AX / PbX2). The perovskite precursor is in the form of a polyhalide plumbate (e.g., PbX3) in a polar solvent. - , PbX4 2-) exist, and the halide coordination number of the polyhalide metallate increases as the concentration of the solution or the ratio of AX / BX2 increases. At this time, the excess A-site cations are located between the polyhalide metallates and play a role in separating the polyhalide metallates so that they do not connect with each other. A quasi-emulsion is formed when a precursor solution with a high precursor concentration and a high AX / PbX2 ratio is used, and when the precursor solution is added to a non-polar solvent, the excess A-site cations interfere with the connection of the polyhalide metallates, preventing the formation of 3D perovskite nanocrystals. At this time, the demulsifier effectively alleviates the interference of the crystal growth of the polyhalide metallate caused by the excess A-site cations, and as a result, the perovskite nanocrystals can be formed only when the demulsifier is included.

[0080] According to one embodiment of the present invention, the molar ratio of AX:BX2 contained in the precursor solution may be 4:1, 3.5:1, 3:1, 2.5:1, 2:1, 1.5:1 to 1:1. When the molar ratio of AX:BX2 contained in the precursor solution satisfies the above-described range, a high-coordination polyhalide metallate can be formed.

[0081] In contrast, conventional LARP synthesis utilizes low precursor concentrations, low AX / PbX2 ratios, and precursor solutions containing ligands. In this case, the coordination number of the formed polyhalide metallates is low, and the amount of A-site cations is small, so that the bonds between polyhalide metallates are not sufficiently disturbed. Therefore, when the precursor solution is added to a nonpolar solvent, 3D perovskite nanocrystals are formed. Therefore, a demulsifier is not required in the conventional LARP synthesis.

[0082] Low-temperature injection can effectively increase PLQY when following a quasi-emulsion mechanism, but may not be effective in increasing PLQY when following a LARP synthesis mechanism.

[0083] FIG. 1 is a drawing briefly showing a method for manufacturing perovskite nanocrystals according to one embodiment of the present invention.

[0084] Figure 2 is a flowchart of a method for manufacturing perovskite nanocrystals according to one embodiment of the present invention.

[0085] First, the perovskite nanocrystals manufactured by the method according to the present invention will be described in more detail.

[0086] According to one embodiment of the present invention, the perovskite nanocrystal may be represented by the following chemical formula 1.

[0087] [Chemical Formula 1]

[0088] ABX3

[0089] In the above chemical formula 1, A is a monovalent cation, B is a divalent metal cation, and X is a halogen anion.

[0090] According to one embodiment of the present invention, A may be an organic amidinium ion, an organic ammonium ion, Cs, Rb, or a combination thereof. Preferably, A may be an organic amidinium ion, an organic ammonium ion, or a combination thereof. When A is an organic amidinium ion, an organic ammonium ion, or a combination thereof, the produced perovskite nanocrystal may have a luminescence wavelength band suitable for the Rec. 2100 standard.

[0091] According to one embodiment of the present invention, B may be a transition metal ion, a rare earth metal ion, an alkaline earth metal ion, a derivative thereof, or a combination thereof. More specifically, B may be a divalent cation of Pb, Mn, Cu, Ga, Ge, In, Al, Sb, Bi, Po, Sn, Eu, Yb, Ni, Co, Fe, Cr, Pd, Cd, Ca, or Sr, or a combination thereof.

[0092] According to one embodiment of the present invention, X may be a halogen ion or a combination of different halogen ions. More specifically, X may be Cl - , Br - , I - Or it can be a combination of these. By controlling the composition of the halogen anions among those described above, the emission wavelength of the perovskite nanocrystal can be controlled.

[0093] According to one embodiment of the present invention, the organic amidinium ion is formamidinium (NH2CH=NH2 + ), guanidinium (NH2C(NH2)=NH2 + ), acetamidinium (NH2C(CH3)=NH2 + ) or a combination thereof.

[0094] According to one embodiment of the present invention, the organic ammonium ion is methylammonium, ethylammonium, tert-butylammonium, diethylammonium, dimethylammonium, ethane-1,2,-diammonium, imidazolium, npropylammonium, iso-propylammonium, pyrrolidinium, CH(NH2)2 + , C x H 2x+1 (CNH3)+ , (CH3NH3) n + , ((C x H 2x+1 ) n NH3) n (CH3NH3) n + , R(NH2)2 + , (C n H 2n+1 NH3) n + , (CF3NH3) + , CF3NH3) n + , ((C x F 2x+1 ) n NH3) n (CF3NH3) n + , ((C x F 2x+1 ) n NH3)2 + , (C n F 2n+1 NH3) n + , (wherein, R is an alkyl group, and n and x are independently integers from 1 to 100) or a combination thereof.

[0095] According to one embodiment of the present invention, the perovskite nanocrystal may further include a plurality of organic ligands on at least a portion of the surface. By further including the organic ligands on at least a portion of the surface of the perovskite nanocrystal, the surface of the perovskite nanocrystal can be stabilized, thereby improving the stability of the perovskite nanocrystal, and agglomeration between nanocrystal particles can be prevented, thereby improving dispersibility.

[0096] According to one embodiment of the present invention, the organic ligand may include a carboxylic acid organic ligand, an amine organic ligand, or a combination thereof. By including the carboxylic acid organic ligand, an amine organic ligand, or a combination thereof, the interaction between the organic ligand and the perovskite precursor may increase as the temperature of the ligand solution decreases.

[0097] According to one embodiment of the present invention, the carboxylic acid organic ligand is 4,4'-azobis(4-cyanovaleric acid), acetic acid, 5-aminosalicylic acid, acrylic acid, L-aspentic acid, 6-bromohexanoic acid, bromoacetic acid, dichloro acetic acid, ethylenediaminetetraacetic acid, isobutyric acid, itaconic acid, maleic acid, r-Maleimidobutyric acid, L-Malic acid, 4-Nitrobenzoic acid, 1-Pyrenecarboxylic acid, butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid pentadecanoic acid, hexadecenoic acid, heptadecanoic acid, octadecanoic acid,It may include oleic acid or a combination thereof, preferably oleic acid.

[0098] According to one embodiment of the present invention, the amine organic ligand may include butylamine, hexylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, oleylamine, N,N-diisopropylethylamine, ethylenediamine, hexamethylenetetramine, methylamine, N,N,N,N-tetramethyleneethylenediamine, triethylamine, diethanolamine, 2,2-(ethylenedioxyl)bis-(ethylamine), 2-methyl-1,5-pentanediamine, 3-methoxytriphenyl-amine, 1,4-phenylenediamine, N,N,N,N-pentamethyl diethylenetriamine, triethylenetetramine, rhodamine, diethylamine, ethylindiamine or a combination thereof, and preferably may include decylamine. there is.

[0099] The perovskite nanocrystals manufactured by the manufacturing method according to one embodiment of the present invention may have a section in which the photoluminescence efficiency (PLQY) is 85% or higher during measurement after synthesis, and the photoluminescence efficiency of 85% is a standard value that must be achieved for commercialization. More preferably, it may be 90% or higher, 91% or higher, 92% or higher, 93% or higher, 94% or higher, 95% or higher, 96% or higher, 97% or higher, 98% or higher, 99% or higher, or 100%. The photoluminescence efficiency of the perovskite nanocrystals may decrease as the synthesis scale increases, but the perovskite nanocrystals synthesized in large quantities may have a section in which the photoluminescence efficiency (PLQY) is 85% or higher during measurement after synthesis. Specifically, the photoluminescence efficiency may be a value measured for a solution in which the perovskite nanocrystals are dispersed. The above photoluminescence efficiency can be measured using a spectrofluorometer utilizing an integrating sphere. FP-8500 (Jasco) can be used as the spectrofluorometer, and ILF-835 (Jasco) can be used as the integrating sphere.

[0100] The perovskite nanocrystal manufactured by the manufacturing method according to one embodiment of the present invention, wherein the halogen anion is Br - In this case, it may have a photoluminescence (PL) peak at a wavelength ranging from 525 nm to 535 nm. By having a PL peak at a wavelength in the above-described range, it may be suitable for implementing a pure green color according to the Rec. 2100 standard.

[0101] Hereinafter, a method for manufacturing perovskite nanocrystals according to one embodiment of the present invention will be described in more detail.

[0102] A method for manufacturing a perovskite nanocrystal according to an embodiment of the present invention can provide a high-performance perovskite nanocrystal having a photoluminescence efficiency (PLQY) close to 100%.

[0103] The method for manufacturing perovskite nanocrystals according to one embodiment of the present invention can be performed under atmospheric conditions and can be easily mass-produced.

[0104] According to an embodiment of the present invention, a method for manufacturing perovskite nanocrystals is such that when the precursor solution is added to the ligand solution, nuclei of perovskite nanocrystals are formed within the ligand solution, and as the solution is stirred and reacted, the particles gradually grow, thereby forming perovskite nanocrystals.

[0105] The above ligand solution can be prepared by adding the above-described organic ligand to a mixed solution of a nonpolar solvent and an anti-emulsifier and stirring.

[0106] According to one embodiment of the present invention, the nonpolar solvent may include chloroform, chlorobenzene, dichlorobenzene, toluene, xylene, acetone, cyclohexane, benzene, methanol, ethanol, ethylene glycol, 2-propanol, 1-butanol, tetrahydrofuran, acetonitrile, benzonite, or a combination thereof.

[0107] The above-mentioned demulsifier may be a polar solvent such as alcohol or acetone. More specifically, the above-mentioned demulsifier may include acetone, ethanol, methanol, 1-propanol, 1-butanol, tert-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, benzyl alcohol, benzyl benzoate, benzyl acetate, or a combination thereof.

[0108] Preferably, the nonpolar solvent may include toluene, and the demulsifier may include 1-butanol. By including the nonpolar solvent and the demulsifier as described above, crystallization of the perovskite nanocrystals can be induced, and the structure of the perovskite nanocrystals can be kept from dissolving.

[0109] The precursor solution containing the perovskite precursor and the polar solvent can be prepared by adding the perovskite precursors for producing the perovskite nanocrystals described above to the polar solvent and stirring.

[0110] More specifically, the perovskite precursor may contain AX, A'X, BX2, and / or BX3. The polar solvent is used to dissolve and disperse the perovskite precursor, and is not particularly limited as long as it is commonly used in the art. For example, the polar solvent may include dimethylformamide, dimethylsulfoxide, gamma butyrolactone, N-methylpyrrolidone, or isopropyl alcohol.

[0111] According to one embodiment of the present invention, the total concentration of the perovskite precursor of the precursor solution may be 0.1 M or more, 0.15 M or more, 0.2 M or more, 0.25 M or more, 0.3 M or more, 0.35 M or more, 0.4 M or more, 0.45 M or more, 0.5 M or more, 0.55 M or more, 0.6 M or more, 0.65 M or more, 0.7 M or more, 0.75 M or more, or 0.8 M or more.

[0112] According to one embodiment of the present invention, the total concentration of the perovskite precursor in the precursor solution may be 10 M or less.

[0113] In the present invention, the total concentration of the perovskite precursor of the precursor solution is understood to mean the total molar concentration of the perovskite precursor compound including the above-described AX and BX2 contained in the precursor solution.

[0114] According to one embodiment of the present invention, the step of adding the precursor solution to the ligand solution may be dropping the precursor solution into the ligand solution.

[0115] According to one embodiment of the present invention, the step of adding the precursor solution to the ligand solution may be performed simultaneously with stirring the ligand solution.

[0116] According to one embodiment of the present invention, the step of stirring the ligand solution to which the precursor solution has been added may be performed for at least 1 minute. More specifically, the step may be performed for at least 5 minutes and no more than 30 minutes.

[0117] Since the method for manufacturing perovskite nanocrystals according to one embodiment of the present invention can be performed under atmospheric conditions, the type of reactor is not particularly limited.

[0118] According to one embodiment of the present invention, before the step of adding the precursor solution to the ligand solution, the step of adding the precursor solution to the ligand solution can be performed at a desired temperature by controlling the temperature of the ligand solution.

[0119] According to one embodiment of the present invention, the step of adding the precursor solution is performed at a temperature of 15°C or lower. Since the step of adding the precursor solution is performed at a temperature of 15°C or lower, the interaction between the organic ligand and the perovskite precursor can be increased, thereby preventing rapid growth of the perovskite nanocrystals. By preventing rapid growth of the perovskite nanocrystals, defects in the manufactured perovskite nanocrystals can be reduced, crystallinity can be improved, uniformity can be high, and thus the photoluminescence quantum yield (PLQY) can be increased.

[0120] More specifically, the temperature at which the step of adding the precursor solution is performed may be 15°C or less, 14°C or less, 13°C or less, 12°C or less, 11°C or less, 10°C or less, 9°C or less, 8°C or less, 7°C or less, 6°C or less, 5°C or less, or 4°C or less, and may be -20°C or more, -15°C or more, -14°C or more, -13°C or more, -12°C or more, -11°C or more, -10°C or more, -9°C or more, -8°C or more, -7°C or more, -6°C or more, -5°C or more, -4°C or more, -3°C or more, -2°C or more, -1°C or more, or 0°C or more. More specifically, the temperature range at which the step of adding the precursor solution is performed can be set to a minimum value and a maximum value among the two ranges selected from among these. By controlling the temperature at which the step of forming perovskite nanocrystals is performed within the above-described range, the photoluminescence efficiency (PLQY) of the perovskite nanocrystals produced can be further improved.

[0121] Preferably, the step of adding the precursor solution can be performed at a temperature of -4°C or higher and 4°C or lower. When the temperature at which the step of adding the precursor solution is performed satisfies the above-described range, the photoluminescence efficiency of the manufactured perovskite nanocrystals can be significantly high. Below -4°C, the particles tend to form a two-dimensional plate-like structure rather than a three-dimensional cubic structure, so the luminescence efficiency may be slightly lower and the change in the luminescence wavelength may occur more rapidly. When it is above 4°C, the crystallinity of the particles is low and there are many defects, so the luminescence efficiency may be lowered. Therefore, the synthesis temperature is most appropriate when it is 0°C or a range slightly lower than this, up to -4°C.

[0122] According to one embodiment of the present invention, the temperature at which the step of stirring the ligand solution to which the precursor solution is added is performed may be maintained the same as or different from the temperature at which the step of adding the precursor solution is performed. Depending on the temperature at which the step of stirring the ligand solution to which the precursor solution is added is performed, the growth rate of the perovskite nanocrystals may vary, and consequently, the total time required to manufacture the final perovskite nanocrystals may vary. However, the luminescence characteristics of the final perovskite nanocrystals manufactured are mainly affected by the temperature at which the precursor solution is added, and the effect of the temperature at which the stirring step is performed may be minimal.

[0123] More specifically, the temperature at which the step of stirring the ligand solution to which the precursor solution is added may be -20°C or higher and 50°C or lower, but is not particularly limited thereto. For example, the temperature at which the step of stirring the ligand solution to which the precursor solution is added may be -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C.

[0124] A manufacturing method according to one embodiment of the present invention may further include, after the step of introducing a ligand solution containing an organic ligand, a non-polar solvent, and a demulsifier into the reactor, a step of cooling the reactor containing the ligand solution. By including the step of cooling the reactor containing the ligand solution, the temperature of the ligand solution can be controlled to a temperature at which the step of forming perovskite nanocrystals is performed, and by controlling the temperature of the ligand solution, the initial stage of the perovskite nanocrystal formation reaction can be performed within the above-described temperature range.

[0125] A manufacturing method according to one embodiment of the present invention may further include a step of obtaining perovskite nanocrystals by centrifuging a solution containing perovskite nanocrystals manufactured after the step of stirring the ligand solution to which the precursor solution has been added. The perovskite nanocrystals obtained by the centrifugation may have their luminous efficiency increased by removing impurities.

[0126] Another embodiment of the present invention provides a perovskite light-emitting device comprising: an electrode; a hole injection layer positioned on the first electrode; a light-emitting layer positioned on the hole injection layer and comprising perovskite nanocrystals manufactured by a method according to the embodiment of the present invention; an electron injection layer positioned on the light-emitting layer; and a second electrode positioned on the electron injection layer.

[0127] According to one embodiment of the present invention, the first electrode or the second electrode may include, but is not particularly limited to, a metal, a conductive polymer, a metallic carbon nanotube, graphene, reduced graphene oxide, metal nanowire, carbon nanodot, metal nanodot, conductive oxide, or a combination thereof.

[0128] According to one embodiment of the present invention, the hole injection layer may include a material generally used in the art as a layer for facilitating the injection of holes into the light emitting layer. The hole injection layer may include, for example, mCP (N,Ndicarbazolyl-3,5-benzene); PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate); NPD (N,N′'-diphenylbenzidine); TPD (N,N′'-Bis(3-methylphenyl)-N,N′'-diphenylbenzidine); DNTPD (N4,N4′'-Bis[4-[bis(3-methylphenyl)amino]phenyl]-N4,N4′'-diphenyl-[1,1′'-biphenyl]-4,4′'-diamine); N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl; Porphyrin compound derivatives such as N,N,N'N'-tetra-p-tolyl-4,4'-diaminobiphenyl; N,N,N'N'-tetraphenyl-4,4'-diaminobiphenyl; copper(II) 1,10,15,20-tetraphenyl-21H,23H-porphyrin; triarylamine derivatives such as TAPC (1,1-Bis[4-[N,N'-Di(p-tolyl)Amino]Phenyl]Cyclohexane); N,N,N-tri(p-tolyl)amine, 4,4', 4'-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine; carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole; phthalocyanine derivatives such as metal-free phthalocyanines and copper phthalocyanines; starburst amine derivatives; enaminestilbene derivatives; Derivatives of aromatic tertiary amines and styryl amine compounds; polysilanes or combinations thereof.

[0129] According to one embodiment of the present invention, the electron injection layer may include a material generally used in the art as a layer for facilitating injection of electrons from the cathode to the light-emitting layer. The electron injection layer is, for example, LiF, NaCl, CsF, Li2O, BaO, BaF2, Liq (lithium quinolate), aluminum doped zinc oxide (AZO), alkali metal (Li, Na, K, Rb, Cs or Fr) doped AZO, TiOx (x is a real number from 1 to 3), indium oxide, tin oxide, zinc oxide, zinc tin oxide, gallium oxide, tungsten oxide, aluminum oxide, titanium oxide, vanadium oxide (V2O5, vanadium(IV) oxide, molybdenum oxide, copper oxide, nickel oxide, copper aluminum oxide (CAO, CuAlO2), zinc rhodium oxide (ZRO, iron oxide, chromium oxide, bismuth oxide, IGZO) (indium-Gallium Zinc Oxide), ZrO2 or combinations thereof, but is not particularly limited thereto.

[0130] According to one embodiment of the present invention, the light-emitting device may further include a hole transport layer including a hole transport material between the light-emitting layer and the hole injection layer.

[0131] According to one embodiment of the present invention, the light-emitting device may further include an electron transport layer between the light-emitting layer and the electron injection layer.

[0132] According to one embodiment of the present invention, the first electrode, the second electrode, the hole injection layer, the electron injection layer, the hole transport layer, and the electron transport layer can be formed using a deposition method or a coating method, for example, spraying, spin coating, dipping, printing, doctor blading, or using an electrophoresis method.

[0133] The light-emitting layer including the perovskite nanocrystals can be formed through a solution process such as spin coating, spray coating, or inkjet printing using a solution including the perovskite nanocrystals. Since the light-emitting layer can be manufactured based on a solution process, the manufacturing cost of the perovskite light-emitting device can be reduced.

[0134] A perovskite light-emitting device according to one embodiment of the present invention may have an external quantum efficiency (EQE) of 25% or more.

[0135] A perovskite light-emitting device according to one embodiment of the present invention may have an electroluminescence (EL) peak at a wavelength ranging from 525 nm to 535 nm. By having an electroluminescence (EL) peak at a wavelength ranging from 525 nm to 535 nm, a pure green color according to the Rec. 2100 (or Rec. 2020) standard can be realized.

[0136] According to one embodiment of the present invention, the perovskite light-emitting device may have a full width at half maximum (FWHM) of the electroluminescence (EL) peak of 30 nm or less, and preferably 25 nm or less, 23 nm or less, or 21 nm or less. When the full width at half maximum (FWHM) of the electroluminescence (EL) peak satisfies the above-described range, the perovskite light-emitting device may realize high color purity.

[0137] Hereinafter, the present invention will be described in detail using examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention is not limited to the examples described below. The examples in this specification are provided to more fully explain the present invention to those of ordinary skill in the art.

[0138] Example 1-1: Preparation of perovskite nanocrystals

[0139] Materials for the production of perovskite nanocrystals were prepared as follows. All compounds were purchased and used without further treatment.

[0140] - Perovskite precursors: formamidinium bromide (FABr, Greatcell SolarDyesol), guanidinium bromide (GABr, Greatcell SolarDyesol), lead(II) bromide (PbBr2, Sigma-Aldrich)

[0141] - Organic ligand: oleic acid (OA, 90%, Alfa Aesar), n-decylamine (98%, TCI)

[0142] - Polar solvent: N,N-dimethylformamide (DMF, >99.8%, Sigma-Aldrich)

[0143] - Nonpolar solvent: Toluene (99.5%, Samchun Chemical)

[0144] - Emulsifier: 1-butyl alcohol (99%, Samjeon Chemical)

[0145] First, a precursor solution was prepared by dissolving 0.18 mmol of FABr, 0.02 mmol of GABr, and 0.1 mmol of PbBr2 in 0.5 mL of DMF. The total concentration of the perovskite precursor contained in the precursor solution was calculated to be 0.6 M. A ligand solution containing 0.3 mL of oleic acid and 0.024 mL of n-decylamine as organic ligands, 5 mL of toluene as a nonpolar solvent, and 2 mL of 1-butanol as a demulsifier was prepared. Then, the ligand solution was cooled to adjust the temperature to 0 °C.

[0146] Then, the prepared precursor solution was added dropwise to the ligand solution adjusted to 0 °C while stirring vigorously. After adding all of the prepared precursor solution dropwise, the mixture was stirred for 10 minutes, transferred to a Falcon tube, and centrifuged at 12,000 rpm for 10 minutes. After centrifugation, the aggregated particles were collected and redispersed in 1 mL of toluene, centrifuged a second time at 3,750 rpm for 10 minutes, and the supernatant was collected to obtain perovskite nanocrystals FA. 0.9 GA 0.1 A solution containing PbBr3 was obtained.

[0147] Examples 1-2, 1-3, 1-4, 1-5 and Comparative Example 1-1

[0148] Perovskite nanocrystal FA was prepared in the same manner as in Example 1-1, except that the temperature of the precursor solution was controlled by adjusting the temperature of the ligand solution as shown in Table 1 below, thereby controlling the temperature of the step in which the precursor solution was added to the ligand solution. 0.9 GA 0.1 A solution containing PbBr3 was obtained.

[0149] Example 1-1 Example 1-2 Example 1-3 Example 1-4 Example 1-5 Comparative Example 1-1 Temperature of ligand solution when precursor solution is injected (℃) 0-44 10 15 20

[0150]

[0151] Examples 1-6 to 1-8

[0152] Perovskite nanocrystal FA was prepared in the same manner as in Example 1-1, except that the temperature of the precursor solution was controlled by adjusting the temperature of the ligand solution as shown in Table 2 below, thereby controlling the temperature of the step in which the precursor solution was added to the ligand solution. 0.9 GA 0.1 A solution containing PbBr3 was obtained.

[0153] Example 1-6 Example 1-7 Example 1-8 Temperature of ligand solution when precursor solution is injected (℃) -10-15-20

[0154]

[0155] Examples 1-9 to 1-14 and Comparative Examples 1-2 to 1-4

[0156] In preparing the precursor solution, the relative content ratios of FABr, GABr and PbBr2 were not changed, and the total concentration of the perovskite precursor included in the precursor solution was adjusted as shown in Table 3 below, and the temperature of the ligand solution was adjusted as shown in Table 3 below to control the temperature of the step in which the precursor solution was added to the ligand solution, except that the perovskite nanocrystal FA was prepared in the same manner as in Example 1-1. 0.9 GA 0.1 A solution containing PbBr3 was obtained.

[0157] Example 1-9 Example 1-10 Comparative Example 1-2 Example 1-11 Example 1-12 Comparative Example 1-3 Example 1-13 Example 1-14 Comparative Example 1-4 Temperature of ligand solution at the time of precursor solution injection (℃) 0 1 0 2 0 0 1 0 2 0 0 1 0 2 0 Total concentration of perovskite precursor included in precursor solution (M) 0.07 5 0.07 5 0.07 5 0.1 5 0.1 5 0.1 5 0.1 5 0.3 0.3

[0158]

[0159] Hereinafter, in the description of examples and experimental examples, the films including perovskite nanocrystals are samples obtained by spin-coating a solution including perovskite nanocrystals obtained in the above examples and comparative examples, and films manufactured using the drop casting method were used only when analyzing XRD patterns.

[0160]

[0161] <Experimental Example 1> Observation of changes in the coordination number of polyhalide metallate contained in the precursor solution

[0162] The change in the coordination number of the polyhalide metallate contained in the precursor solution was observed depending on the total concentration of the perovskite precursor contained in the precursor solution and the molar ratio (AX:BX2) of the perovskite precursor.

[0163] Specifically, FABr and GABr as perovskite precursors AX and PbBr2 as perovskite precursor BX2 were dissolved in DMF to prepare precursor solutions satisfying the total concentration of perovskite precursors and the molar ratio of perovskite precursors (AX:BX2) shown in Table 4 below. Then, UV-visible absorption analysis was performed on the precursor solutions, and the results are shown in Fig. 3.

[0164] Reference Example 1-1 Reference Example 1-2 Reference Example 1-3 Reference Example 1-4 Reference Example 1-5 Reference Example 1-6 Total concentration of perovskite precursor contained in precursor solution (M) 0.0075 0.037 5 0.075 0.15 0.3 0.6 Perovskite precursor ratio (AX / BX2) 2 2 2 2 2 Reference Example 2-1 Reference Example 2-2 Reference Example 2-3 Reference Example 2-4 Reference Example 2-5 Reference Example 2-6 Total concentration of perovskite precursor contained in precursor solution (M) 0.2 0.3 0.4 0.5 0.6 0.7 Perovskite precursor molar ratio (AX / BX2) 0 0.5 1 1.5 2 2.5

[0165]

[0166] As shown in Fig. 3, it was confirmed that the UV-visible absorption spectrum shifted to a longer wavelength band as the total concentration of the perovskite precursor included in the precursor solution increased and as the perovskite precursor ratio (AX / BX2) increased. As the coordination number increased in the polyhalide metallate in which the metal cation is Pb and the halogen anion is Br, the absorption peak shifted to a longer wavelength band. Specifically, when the coordination number was 2 (PbBr2), it was 285 nm, and when the coordination number was 3 (PbBr3). - ) 310 nm, 4 in case of (PbBr4 2-) is known to have an absorption peak at 360 nm, and it can be confirmed that the absorption spectrum shifts to a longer wavelength band as the coordination number increases. That is, through Fig. 3, in the case where the B site metal cation is Pb and the halogen anion is Br, it was confirmed that a highly coordinated polyhalide metallate having a coordination number of 3 or more can be obtained from a precursor solution in which the total concentration of the perovskite precursor satisfies 0.1 M or more and the perovskite precursor ratio (AX / BX2) satisfies 1 or more.

[0167] The UV-Visible absorption values ​​of the perovskite precursor solution were measured using a spectrophotometer (PerkinElmer Lambda 465).

[0168] <Experimental Example 2> Investigation of ligand behavior according to temperature

[0169] To investigate the temperature-dependent behavior of the ligand, a ligand solution containing oleic acid and n-decylamine, and containing 5 mL of toluene and 2 mL of 1-butanol as solvents, was prepared. In addition, as a control group, a solution containing only oleic acid, and containing 5 mL of toluene and 2 mL of 1-butanol as solvents, and a solution containing only n-decylamine, and containing 5 mL of toluene and 2 mL of 1-butanol as solvents, were prepared. The conductivity (μS / cm) of the three solutions was measured over the temperature range of -5 °C to 15 °C.

[0170] Figure 4 is a diagram showing the conductivity (μS / cm) as a function of temperature of a ligand solution containing oleic acid and n-decylamine, a solution containing only oleic acid, and a solution containing only n-decylamine.

[0171] Referring to Figure 4, a correlation of increasing conductivity with decreasing temperature was observed only in the ligand solution containing oleic acid and n-decylamine. The increase in conductivity was due to the presence of decyl ammonium (DAm) in the solution.+ ) and oleate (OA - ) due to the increase in ion concentration.

[0172] Figure 5 shows the temperature dependence of a solution containing oleic acid, n-decylamine, and perovskite precursor (PbBr2). 1 This is a diagram showing the results of H-NMR analysis.

[0173] Referring to Figure 5, as the temperature of the ligand solution decreases, DAm + -NH3 of + The resonance corresponding to the part exhibited a downfield shift with observable line broadening, which indicates that DAm decreases with decreasing temperature of the ligand solution. + It was confirmed that the interaction between the ligand ions and the perovskite precursor increases. That is, as the temperature decreases, a greater number of ligand ions interact more strongly with the perovskite.

[0174] Figure 6 is an XRD pattern for a film including perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0175] Referring to Figure 6, as the temperature of the perovskite nanocrystal formation reaction decreases, the film containing perovskite nanocrystals tends to preferentially assemble in the (100) direction during solvent evaporation during drop casting. This preferential assembly of nanocrystals indicates that individual perovskite nanocrystals have high crystallinity, well-defined shapes, and nearly identical shapes.

[0176] <Experimental Example 3> Analysis of perovskite nanocrystal characteristics

[0177] In order to investigate the surface and structural properties of perovskite nanocrystals manufactured according to the manufacturing method of the present invention, the solid state 1 H magic-angle-spinning (MAS) NMR spectroscopy and X-ray photoelectron (XPS) analysis were used.

[0178] Figure 7 shows the solid state of perovskite nanocrystals manufactured in Example 1-1, Example 1-4, and Comparative Example 1-1. 1 This is a diagram showing the H MAS NMR spectrum.

[0179] Referring to Fig. 7, as the initial temperature of the perovskite nanocrystal formation reaction decreased, that is, from Comparative Example 1-1 to Example 1-4 and Example 1-1, the resonance intensity of decyl ammonium (~7 ppm) in the spectra of the manufactured perovskite nanocrystals increased and the resonance intensity of monovalent organic cations (FA, GA) decreased (7.4~8.8 ppm). The change in the resonance intensity of decyl ammonium and organic cations (FA, GA) suggests that the monovalent organic cations on the surface of the perovskite nanocrystals were replaced with decyl ammonium ligands.

[0180] Figure 8 is a diagram showing the relative content ratios of carbon to lead (C / Pb), nitrogen to lead (N / Pb), and bromine to lead (Br / Pb) contained in perovskite nanocrystals manufactured in Examples 1-1, 1-4, and Comparative Example 1-1. The content ratios were determined through XPS analysis.

[0181] Referring to Figure 8, the C / Pb ratio was the highest in Example 1-1, which had the lowest temperature for the perovskite nanocrystal formation reaction, indicating a higher concentration of ligands. In addition, the relatively high N / Pb and Br / Pb ratios of the perovskite nanocrystals prepared in Examples 1-1 and 1-4 indicate that defect formation was suppressed during the perovskite nanocrystal formation process. More specifically, in Examples 1-1 and 1-4, despite the low initial temperature of the perovskite nanocrystal formation reaction resulting in the replacement of more monovalent organic cations on the nanocrystal surface with decyl ammonium ligands, the N / Pb ratio was maintained or increased without decreasing, indicating a decrease in monovalent organic cation site vacancies incorporated into the bulk. In addition, the Br / Pb ratio increased as the temperature of the perovskite nanocrystal formation reaction decreased, indicating that the formation of vacancies in halogen sites was suppressed.

[0182] <Experimental Example 4> Crystal analysis of perovskite nanocrystals

[0183] Figure 9 shows high-resolution scanning transmission electron microscopy (HR-STEM) and fast Fourier transform (FFT) images of perovskite nanocrystals prepared in Example 1-1. The HR-STEM images were taken using a Cs-corrected monochromated TEM (Themis Z, Thermo Fischer Co., Ltd).

[0184] Referring to Figure 9, it can be confirmed that the perovskite nanocrystals manufactured in Example 1-1 have a rectangular parallelepiped shape and a cubic structure.

[0185] Figure 10 is a high-resolution (iDPC)-STEM image of the perovskite nanocrystals of Example 1-1 (a) and the perovskite nanocrystals of Comparative Example 1-1 (b) (scale bar represents 1 nm). The (iDPC)-STEM images were taken using a Cs-corrected monochromated TEM (Themis Z, Thermo Fischer Co., Ltd).

[0186] Referring to FIG. 10, defect suppression is visually observed in the perovskite nanocrystal (a) manufactured by the manufacturing method according to the present invention, whereas in the case of the perovskite nanocrystal (b) of Comparative Example 1-1 in which the temperature of the nanocrystal formation step was 20°C, irregularity with the presence of vacancy defects was observed.

[0187] Figure 11 is a diagram showing the particle size distribution of perovskite nanocrystals prepared in Examples 1-1 to 1-5 and Comparative Example 1-1. The particle size of the perovskite nanocrystals was calculated from the captured TEM images. The transmission electron microscope (TEM) images were taken using a JEM-ARM200F (JEOL) microscope operating at an accelerating voltage of 200 kV.

[0188] Referring to Figure 11, the manufacturing method according to the present invention formed perovskite nanocrystals of smaller sizes. As the temperature of the perovskite nanocrystal formation reaction decreased, the size of the perovskite nanocrystals decreased, and the size distribution was more uniform.

[0189] <Experimental Example 5> Evaluation of the photoluminescence properties of perovskite nanocrystals

[0190] Figure 12 is a diagram showing the photoluminescence quantification (PLQY) measured for a solution (a) and a film (b) containing perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0191] The photoluminescence efficiency values ​​of solutions containing perovskite nanocrystals were measured using a spectrofluorometer (JASCO FP8500) equipped with a 100 nm integrating sphere (ILF-835), and the excitation wavelength was 365 nm, and determined using Jasco SpectraManager II software. The photoluminescence efficiency values ​​of films containing perovskite nanocrystals were measured using a 325 nm continuous wave He:Cd laser with a PMT detector and an integrating sphere.

[0192] Referring to Fig. 12, as the temperature of the step of adding the precursor solution to the ligand solution decreased, the photoluminescence efficiency of the perovskite nanocrystals significantly increased, and in particular, when the temperature of the step was 10°C, the perovskite nanocrystals of Examples 1-4 reached a photoluminescence efficiency of approximately 95% in both the solution and film forms. In addition, it was confirmed that the photoluminescence efficiency reached 100% in both the solution and film forms when the temperature of the nanocrystal formation step was 4°C or lower.

[0193] On the other hand, the photoluminescence efficiency of the solution containing the perovskite nanocrystals prepared in Comparative Example 1-1, in which the formation of perovskite nanocrystals occurred at 20°C, which is close to room temperature, did not exceed 95%, and the photoluminescence efficiency of the perovskite nanocrystals of Comparative Example 1-1 existing in the form of a film was even lower, exceeding around 85%.

[0194] Figure 13 is a diagram showing the photoluminescence quantification (PLQY) measured for a solution (a) and a film (b) containing perovskite nanocrystals manufactured in Examples 1-6 to 1-8.

[0195] Referring to Figure 13, it was confirmed that as the temperature of the step of adding the precursor solution to the ligand solution decreased below -4°C, the average photoluminescence efficiency of the solution decreased slightly to 99% (synthesis temperature -10°C), 97% (synthesis temperature -15°C), and 93% (synthesis temperature -20°C), and the average photoluminescence efficiency of the film decreased slightly to 97% (synthesis temperature -10°C), 95% (synthesis temperature -15°C), and 87% (synthesis temperature -20°C).

[0196] Figure 14 is a diagram showing the photoluminescence spectrum (PL spectrum) of perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1. The PL spectrum was measured using a spectrofluorometer (JASCO FP8500), and the excitation wavelength was 365 nm.

[0197] Referring to FIG. 14, it can be confirmed that the perovskite nanocrystals manufactured in Examples 1-1 to 1-5 have a PL peak wavelength located within a pure green region (wavelength of 525 nm to 535 nm), which is very close to 532 nm, the wavelength of the green primary color specified in Rec. 2100, indicating that high-purity color expression is possible when the perovskite nanocrystals manufactured in Examples 1-1 to 1-5 are used.

[0198] Figure 15 is a diagram showing the photoluminescence efficiency and PL peak of perovskite nanocrystals previously reported in other studies and perovskite nanocrystals manufactured in Example 1-1. The red asterisk indicates the case synthesized at room temperature (20°C), and the green asterisk indicates the case manufactured in Example 1-1.

[0199] Referring to FIG. 15, it can be confirmed that the perovskite nanocrystals manufactured by the method according to the present invention are the first perovskite nanocrystals to have an emission peak very close to the green primary color according to Rec. 2100 while simultaneously achieving a photoluminescence efficiency of 100%.

[0200] <Experimental Example 6> In-situ analysis of the perovskite nanocrystal formation stage

[0201] To analyze the perovskite nanocrystal formation process in more detail, in-situ analysis was performed during the manufacturing process of Example 1-1 and Comparative Example 1-1.

[0202] The growth reaction of perovskite nanocrystals is initiated by injecting a precursor solution containing the perovskite precursor dissolved in a polar solvent into a ligand solution dissolved in a nonpolar solvent that is miscible with the polar solvent. The polar solvent coordinating with the lead polybromide is removed by the nonpolar solvent, thereby reducing the solubility of the lead polybromide, leading to rapid supersaturation and triggering the nucleation and rapid growth of the perovskite nanocrystals. Therefore, it is inferred that the growth of perovskite nanocrystals is significantly affected by the ligand solution temperature.

[0203] In situ analyses were performed during synthesis to investigate the effect of ligand solution temperature on the nucleation and growth of perovskite nanocrystals. The reaction mixture was continuously stirred throughout the in situ analyses.

[0204] Parts (a) and (b) of FIG. 16 are drawings showing the photoluminescence spectrum measured in-situ in Example 1-1.

[0205] Parts (c) and (d) of Fig. 16 are drawings showing the photoluminescence spectrum measured in-situ in Comparative Example 1-1.

[0206] In-situ photoluminescence spectra were measured using a fiber-coupled CCD spectrometer (Ocean Optics, Maya 2000), with the time point of first addition of the precursor solution to the ligand solution set to 0 s, and measurements were taken at 0.25 s intervals (a, c) and 1 s intervals (b, d), respectively.

[0207] Referring to part (a) of FIG. 16, in the initial stage of synthesis of the method according to the present invention, the photoluminescence spectrum was initiated at shorter wavelengths (~431, 460, 470 nm), indicating that smaller-sized seeds consisting of 2 to 4 monolayers were formed. Furthermore, the photoluminescence intensity gradually increased in small steps over time, indicating the stepwise formation of perovskite nanocrystals.

[0208] On the other hand, referring to part (c) of Fig. 16, in the initial stage of synthesis of Comparative Example 1-1, the nanocrystals exhibited an initial photoluminescence spectrum at a relatively longer wavelength (~500 nm) than in Example 1-1, indicating that larger seeds consisting of six or more monolayers were formed. In addition, the photoluminescence intensity in Comparative Example increased relatively quickly compared to Example, indicating that the perovskite nanocrystals grew rapidly.

[0209] Referring to parts (b) and (d) of FIG. 16, it can be seen that in the method according to the present invention, the nanocrystal growth rate is reduced due to the low injection temperature (0 °C), and it takes a longer time to reach the final size. In contrast, in the comparative example, the perovskite nanocrystals reached the final size at a much faster rate than in the example.

[0210] Figure 17 is an absorption spectrum measured in-situ at 5-minute intervals in Example 1-1(a) and Comparative Example 1-1(b).

[0211] Referring to part (a) of Fig. 17, the in-situ absorption spectrum of Example 1-1 also shows the stepwise growth of perovskite nanocrystals, and more specifically, it shows that initially formed low-dimensional nanocrystals (n=2,3) gradually evolve into high-dimensional nanocrystals (n>3).

[0212] On the other hand, referring to part (b) of Fig. 17, low-dimensional nanocrystals were not found in the in-situ absorption spectrum of Comparative Example 1-1, and this result indicates that the interaction between the ammonium ligand and the perovskite was weakened due to the high temperature of the ligand solution.

[0213] The stepwise growth and slow growth rate of perovskite nanocrystals in the method according to the present invention are presumed to be due to increased competition between ammonium ligands and A-site cations during nanocrystal formation due to the low temperature of the ligand solution.

[0214] To determine the influence of the controlled, step-wise growth of perovskite nanocrystals in the method according to the present invention on their optical properties, the photoluminescence efficiency was measured in situ for the solutions synthesized in Example 1-1 and Comparative Example 1-1. It should be noted that the solutions analyzed were collected prior to centrifugation, and therefore contained polar solvents, reactants, and smaller and larger nanocrystals, resulting in somewhat lower PLQY values.

[0215] Figure 18 is a drawing showing the photoluminescence efficiency measured in-situ for Example 1-1 and Comparative Example 1-1.

[0216] Referring to Fig. 18, in Example 1-1, the photoluminescence efficiency of the grown perovskite nanocrystals was significantly higher than that of the comparative example, even though the nanocrystals were grown from seeds of smaller sizes. This result is presumed to be due to the reduced presence of defects that serve as non-radiative recombination paths in both the bulk and surface of the perovskite nanocrystals.

[0217] Figure 19 is a high-resolution scanning transmission electron microscope (HR-STEM) image of the perovskite nanocrystals manufactured in Example 1-1(a) and Comparative Example 1-1(b). The scale bar in the HR-STEM image of Figure 19 represents 20 nm.

[0218] Referring to Figure 19, the perovskite nanocrystals (a) manufactured in Example 1-1 showed a rectangular parallelepiped shape with a uniform size, whereas the perovskite nanocrystals (b) manufactured in Comparative Example 1-1 had a wider size distribution and showed various non-rectangular parallelepiped shapes, confirming that the uniformity was damaged.

[0219] <Experimental Example 7> Evaluation of the photoluminescence lifetime of perovskite nanocrystals

[0220] Figure 20 is a diagram showing the photoluminescence lifetime (PL lifetime) of perovskite nanocrystals manufactured in Examples 1-1 to 1-5 and Comparative Example 1-1. The PL lifetime was measured by the time-correlated single photon counting (TCSPC) method using a FluoTime 300 system.

[0221] Referring to Fig. 20, a shorter photoluminescence lifetime was observed as the temperature of the perovskite nanocrystal formation reaction decreased, which is a result of smaller-sized nanocrystals being formed as the temperature of the perovskite nanocrystal formation reaction decreased.

[0222] Figure 21 is a diagram showing the photoluminescence spectrum of perovskite nanocrystals manufactured in Example 1-1(a) and Comparative Example 1-1(b) depending on the temperature.

[0223] Figure 22 is a diagram showing the integrated PL intensity and calculated exciton binding energy according to temperature of perovskite nanocrystals manufactured in Example 1-1 and Comparative Example 1-1.

[0224] Referring to Figures 21 and 22, the confinement of charge carriers was improved in the perovskite nanocrystals of Example 1-1. Specifically, a stronger exciton binding energy (E) was observed in the perovskite nanocrystals of Example 1-1 compared to Comparative Example 1-1. b), which indicates that the manufacturing method according to the present invention induces strong exciton confinement by reducing the size of nanocrystals and suppressing non-radiative recombination centers.

[0225] <Experimental Example 8> Scale-up Experiment of Perovskite Nanocrystal Manufacturing Method

[0226] To confirm the applicability of the method for manufacturing perovskite nanocrystals according to the present invention to industrial-scale production, a scale-up experiment was performed.

[0227] Specifically, perovskite nanocrystals (FA) were prepared in the same manner as in Example 1-1 at scales of 15, 30, 60, 150, and 1000 times the amount of material used for manufacturing perovskite nanocrystals in Example 1-1. 0.9 GA 0.1 A solution containing PbBr3) and an organic ligand surrounding it was prepared.

[0228] Figure 23 shows the perovskite nanocrystals (FA) manufactured at scales of 15x, 30x, 60x, 150x and 1000x (10 L). 0.9 GA 0.1 This is a drawing showing the photoluminescence efficiency and luminescence photograph of a solution containing PbBr3) and an organic ligand surrounding it.

[0229] Referring to FIG. 23, it was confirmed that perovskite nanocrystals having a PLQY close to 100% could be successfully produced even at a scale up to 1000 times larger than that of Example 1-1, thereby proving the applicability and scalability of the method according to the present invention to industrial-scale production.

[0230] Example 2. Fabrication of perovskite light-emitting devices (PeLEDs)

[0231] A perovskite light-emitting device comprising perovskite nanocrystals (hereinafter also referred to as Ci-PeNCs) manufactured using a low-temperature injection method was manufactured through the following process.

[0232] A 70 nm thick ITO patterned glass was successively ultrasonically cleaned in acetone and 2-isopropanol for 15 min each. After evaporation of the residual solvent, the glass was treated with ozone for 10 min. Then, a solution containing poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonate) (PEDOT:PSS) and a perfluorinated ionomer (PFI) in a mass ratio of 1:1 was spin-coated onto the glass to a thickness of 50 nm, and heat-treated at 150 °C for 30 min to form a buffered hole injection layer (Buf-HIL).

[0233] After the glass on which the buffer-hole injection layer was formed was transferred to a glove box, a solution containing the perovskite nanocrystals prepared in Example 1-1 was spin-coated at 500 rpm for 60 seconds to form a perovskite light-emitting layer, and a solution containing 1,3,5-Tris(bromomethyl)-2,4,6-triethyl benzene (TBTB) was spin-coated at 3000 rpm for 60 seconds to form a TBTB layer.

[0234] Then, the sample was transferred to a vacuum evaporator, and an electron transport layer containing TPBi (2,2',2''-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) with a thickness of 45 nm was formed on the light-emitting layer, and a 1 nm thick LiF layer and a 100 nm thick Al layer were sequentially formed to fabricate a PeLED. Finally, the fabricated PeLED was encapsulated using a glass lid and UV-curable epoxy resin in an N2 atmosphere.

[0235] Comparative Example 2 (RT-PeNCs)

[0236] A perovskite light-emitting device comprising perovskite nanocrystals (hereinafter also referred to as RT-PeNCs) manufactured at room temperature (20°C) was manufactured in the same manner as in Example 2, except that a solution comprising perovskite nanocrystals manufactured in Comparative Example 1-1 was used instead of the solution comprising perovskite nanocrystals manufactured in Example 1-1.

[0237] Figure 24 is a schematic diagram of a perovskite light-emitting device manufactured in Example 2.

[0238] <Experimental Example 9> Characteristic Evaluation of Perovskite Light-Emitting Devices

[0239] The luminous efficiency of the perovskite light-emitting devices manufactured in the examples and comparative examples was measured using a Keithley 236 source meter and a spectroradiometer (Minolta CS-2000).

[0240] The external quantum efficiency (EQE) of the light-emitting device was calculated by measuring the full-angle electroluminescence distribution.

[0241] Figure 25 is a diagram showing the electrical efficiency (a) and external quantum efficiency (b) according to voltage of the perovskite light-emitting device manufactured in Example 2 and Comparative Example 2.

[0242] Referring to Fig. 25, the perovskite light-emitting device of Example 2 exhibited superior luminous efficiency in all voltage ranges compared to the light-emitting device of Comparative Example 2, and had an excellent maximum luminous efficiency of 128.6 cd / A. In addition, it was confirmed that the external quantum efficiency was also improved in the perovskite light-emitting device of Example 2, and a maximum external quantum efficiency of 28.3% was achieved.

[0243] In order to confirm that the reproducibility of the perovskite light-emitting device according to the present invention is excellent, a light-emitting device was manufactured using the same method as Example 2 and the external quantum efficiency was measured.

[0244] Figure 26 shows the temperature (T) of the ligand solution when the precursor solution is injected.INJ ) is a diagram showing the external quantum efficiency distribution for 40 light-emitting devices manufactured by the method of Example 2 using perovskite nanocrystals manufactured at 4°C (Example 1-3) and 20°C (Comparative Example 1-1).

[0245] Referring to FIG. 26, the light-emitting device using the perovskite nanocrystals manufactured in Comparative Example 1-1, in which the precursor solution addition step was performed at 20°C, had a low average external quantum efficiency of 13.7%, whereas the light-emitting device using the perovskite nanocrystals manufactured by the method according to the present invention had a significantly superior average external quantum efficiency of 25.0% and a maximum external quantum efficiency of 28.3%. In addition, 40 light-emitting devices manufactured using the perovskite nanocrystals manufactured by the method according to the present invention showed excellent reproducibility in the distribution of external quantum efficiency values.

[0246] Figure 27 is a photograph showing the light emission of the perovskite light-emitting device manufactured in Example 2. The scale bar in Figure 27 represents 10 mm.

[0247] Referring to Figure 27, the area of ​​the perovskite light-emitting device manufactured in Example 2 is about 340 mm 2 It can be confirmed that a large-area perovskite light-emitting device was manufactured. By separating the process of forming perovskite nanocrystals and the process of forming a film of perovskite nanocrystals, a film including perovskite nanocrystals can be manufactured uniformly and over a large area.

[0248] Figure 28 is a diagram showing electroluminescence (EL) spectra at various operating voltages of the perovskite light-emitting device manufactured in Example 2. The image inserted in Figure 28 shows the color coordinates of the perovskite light-emitting device manufactured in Example 2 in the CIE 1931 color space.

[0249] Referring to Fig. 28, the perovskite light-emitting device manufactured in Example 2 had an electroluminescence peak (EL peak) at approximately 530 nm, which is a wavelength in the pure green region, and exhibited a narrow EL spectrum with a full width at half maximum (FWHM) of approximately 21 nm.

[0250] <Experimental Example 10> Analysis of the photoluminescence efficiency of manufactured perovskite nanocrystals according to the concentration of the precursor solution.

[0251] Figure 29 is a diagram showing the photoluminescence efficiency of manufactured perovskite nanocrystals according to the concentration of the precursor solution.

[0252] Specifically, when the concentration of the perovskite precursor in the precursor solution was 0.15 M, 0.3 M, or 0.6 M, the photoluminescence efficiency of the prepared perovskite nanocrystals increased as the temperature of the precursor solution injection step decreased from 20°C to 10°C and from 10°C to 0°C. On the other hand, when the concentration of the perovskite precursor in the precursor solution was 0.075 M, the photoluminescence efficiency of the prepared perovskite nanocrystals decreased as the temperature of the precursor solution injection step decreased below 20°C. This suggests that when the concentration of the perovskite precursor in the precursor solution is 0.1 M or higher, the formation of perovskite nanocrystals occurs by a different synthesis mechanism than when the concentration is lower.

[0253] <Experimental Example 11> Analysis of the photoluminescence efficiency of manufactured perovskite nanocrystals according to the temperature at which the stirring step was performed after the addition of the precursor solution.

[0254] In the above-mentioned Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4, the temperature of the ligand solution was controlled so that the step of adding the precursor solution dropwise to the ligand solution was performed at a specific temperature, but the temperature of the solution was not separately controlled in the stirring step. In order to confirm whether the temperature of the step of stirring the ligand solution to which the precursor solution was added affects the characteristics of the manufactured perovskite nanocrystals, the temperature of the step of adding the precursor solution dropwise to the ligand solution was controlled as shown in Table 5 below, and the temperature of the mixed solution to which the precursor solution was added dropwise was controlled as shown in Table 5 below while stirring. The photoluminescence efficiency and emission peak of the ligand solution were measured in-situ at 3-minute intervals during stirring, and the results are shown in Fig. 30. Here, other conditions than the temperature were the same as those described in Example 1-1. After stirring in each experiment 1 to 9, a solution containing perovskite nanocrystals and organic ligands surrounding them was obtained through centrifugation in the same manner as described in Example 1-1, and the photoluminescence efficiency values ​​of this solution were measured and shown in Table 5.

[0255] Experiment 1 Experiment 2 Experiment 3 Experiment 4 Experiment 5 Experiment 6 Experiment 7 Experiment 8 Experiment 9 Temperature of ligand solution at the time of precursor solution injection (℃) 0 0 0 1 0 1 0 1 0 2 0 2 0 2 0 Temperature of the step of stirring the ligand solution to which the precursor solution was added (℃) 0 2 0 4 0 0 2 0 4 0 0 2 0 4 0 Highest photoluminescence efficiency of synthesized perovskite nanocrystals (%) 1 0 0 1 0 1 0 9 5.8 9 6.4 9 5.0 9 2.7 9 2.0 9 1.5

[0256]

[0257] As shown in Fig. 30, the photoluminescence efficiency and the emission peak wavelength measured in-situ for the ligand solution in experiments satisfying each temperature condition increased as the perovskite nanocrystals were formed. Looking at the graph when the temperature of the precursor solution addition step is 0 ℃, the final photoluminescence efficiency is about 90%, and the final emission peak wavelength is measured to be between about 535 nm and 545 nm when the stirring step temperature is 0 ℃, 20 ℃, and 40 ℃, confirming that the effect of the stirring step temperature on the luminescence characteristics of the perovskite nanocrystals being produced is minimal. Meanwhile, it can be confirmed that the interval between data measured at 3-minute intervals becomes wider as the stirring step temperature increases from 0 ℃ to 40 ℃, which shows that the growth rate of perovskite nanocrystals increases as the stirring step temperature increases.

[0258] <Experimental Example 12> Experimental fabrication of perovskite nanocrystals of various compositions

[0259] Example 3-1, Example 3-2 and Comparative Example 3-1:

[0260] FAPbBr3 perovskite nanocrystals

[0261] A precursor solution was prepared by dissolving 0.2 mmol of FABr (Greatcell SolarDyesol) and 0.1 mmol of PbBr2 (Sigma-Aldrich) in 0.5 mL of DMF (>99.8%, Sigma-Aldrich), and the temperature of the ligand solution was adjusted as shown in Table 6 below to control the temperature of the step in which the precursor solution was added to the ligand solution, thereby obtaining a solution containing perovskite nanocrystals FAPbBr3 in the same manner as in Example 1-1.

[0262] Example 4-1, Example 4-2 and Comparative Example 4-1:

[0263] MAPbBr3 perovskite nanocrystals

[0264] A precursor solution was prepared by dissolving 0.4 mmol of methylammonium bromide (MABr, Greatcell SolarDyesol) and 0.1 mmol of PbBr2 (Sigma-Aldrich) in 0.5 mL of DMF (>99.8%, Sigma-Aldrich), and the temperature of the ligand solution was adjusted as shown in Table 6 below to control the temperature of the step in which the precursor solution was added to the ligand solution, thereby obtaining a solution containing perovskite nanocrystals MAPbBr3 in the same manner as in Example 1-1.

[0265] Examples 5-1 to 5-4 and Comparative Examples 5-1 and 5-2:

[0266] FA 0.9 Cs 0.1 PbBr 1.2 I 1.8 perovskite nanocrystals

[0267] A precursor solution was prepared by dissolving 0.072 mmol of FABr, 0.108 mmol of formamidinium iodide (FAI, Greatcell SolarDyesol), 0.008 mmol of CsBr (Sigma-Aldrich), 0.012 mmol of CsI (Sigma-Aldrich), 0.04 mmol of PbBr2, and 0.06 mmol of PbI2 (Sigma-Aldrich) in 0.5 mL of DMF. A ligand solution containing 0.3 mL of oleic acid and 0.024 mL of n-decylamine as organic ligands, 5 mL of toluene as a nonpolar solvent, and 2 mL of 1-butanol as a demulsifier was prepared. The ligand solution was then cooled to adjust the temperature as shown in Table 6 below.

[0268] Then, 0.15 mL of the prepared precursor solution was added dropwise to the ligand solution while stirring vigorously. As soon as the precursor solution was added dropwise, the mixed solution was observed to change to red. After adding the precursor solution dropwise, the mixed solution was stirred for 5 minutes, transferred to a Falcon tube, and centrifuged at 12,000 rpm for 5 minutes. After centrifugation, the aggregated particles were collected and redispersed in 1 mL of toluene, centrifuged a second time at 3,750 rpm for 5 minutes, and the supernatant was collected to obtain perovskite nanocrystals FA. 0.9 Cs 0.1 PbBr 1.2 I 1.8 A solution containing the perovskite nanocrystal FA was obtained. 0.9 Cs 0.1 PbBr 1.2 I 1.8 The solution containing it was observed to glow red with the naked eye.

[0269] Examples 6-1 to 6-4 and Comparative Examples 6-1 and 6-2:

[0270] FAPbCl 1.2 Br 1.8 perovskite nanocrystals

[0271] Perovskite nanocrystals FAPbCl were prepared in the same manner as in Example 5-1, except that the precursor solution was prepared by dissolving 0.08 mmol of formamidinium chloride (FACl, Greatcell SolarDyesol), 0.12 mmol of FABr, 0.04 mmol of PBBr2, and 0.06 mmol of PbCl2 (Sigma-Aldrich) in 0.5 mL of DMF, and the temperature of the ligand solution was adjusted as shown in Table 6 below to control the temperature of the step in which the precursor solution was added to the ligand solution. 1.2 Br 1.8 A solution containing the perovskite nanocrystal FAPbCl was obtained. 1.2 Br 1.8 The solution containing it was observed to emit blue light with the naked eye.

[0272] Examples 7-1 to 7-4 and Comparative Examples 7-1 and 7-2:

[0273] FAPbI3 perovskite nanocrystals

[0274] Perovskite nanocrystals FAPbCl were prepared in the same manner as in Example 5-1, except that the precursor solution was prepared by dissolving 0.2 mmol of FAI and 0.1 mmol of PbI2 in 0.5 mL of DMF, and the temperature of the ligand solution was adjusted as shown in Table 6 below to control the temperature of the step in which the precursor solution was added to the ligand solution. 1.2 Br 1.8 A solution containing the perovskite nanocrystal FAPbI3 was obtained. The solution containing the perovskite nanocrystal FAPbI3 was observed to exhibit photoluminescence in the infrared region with the naked eye.

[0275] Perovskite Composition Example 3-1 Example 3-2 Comparative Example 3-1 Temperature of ligand solution when FAPbBr3 precursor solution is injected (℃) 0 1 0 2 0 Perovskite Composition Example 4-1 Example 4-2 Comparative Example 4-1 Temperature of ligand solution when MAPbBr3 precursor solution is injected (℃) 0 1 0 2 0 Perovskite Composition Example 5-1 Example 5-2 Example 5-3 Example 5-4 Comparative Example 5-1 Comparative Example 5-2 FA 0.9 Cs 0.1 PbBr 1.2 I 1.8 Temperature of ligand solution at the time of precursor solution injection (℃) 048121620 Perovskite composition Example 6-1 Example 6-2 Example 6-3 Example 6-4 Comparative Example 6-1 Comparative Example 6-2 FAPbCl 1.2 Br 1.8 Temperature of ligand solution when precursor solution is injected (℃) 0 48 12 16 20 Perovskite composition Example 7-1 Example 7-2 Example 7-3 Example 7-4 Comparative Example 7-1 Comparative Example 7-2 FAPbI3 Temperature of ligand solution when precursor solution is injected (℃) 0 48 12 16 20

[0276]

[0277] FIG. 31 is a diagram showing the luminescence spectrum (a) and photoluminescence efficiency (PLQY) (b) measured for a solution containing FAPbBr3 perovskite nanocrystals prepared in Examples 3-1, 3-2 and Comparative Example 3-1, and the luminescence spectrum (c) and photoluminescence efficiency (PLQY) (d) measured for a solution containing MAPbBr3 perovskite nanocrystals prepared in Examples 4-1, 4-2 and Comparative Example 4-1.

[0278] As shown in Fig. 31, the photoluminescence (PL) peak of both FAPbBr3 and MAPbBr3 perovskite nanocrystals slightly shifted to a shorter wavelength band as the temperature of the precursor solution addition step decreased from 20°C to 10°C and from 10°C to 0°C, and the photoluminescence efficiency of the FAPbBr3 perovskite nanocrystal solution was confirmed to significantly improve from about 78% (Comparative Example 3-1) to about 94% (Example 3-2) and about 100% (Example 3-1) as the temperature decreased. In addition, in the case of MAPbBr3, the photoluminescence efficiency, which was about 92% (Comparative Example 4-1), was confirmed to improve to about 97% (Example 4-2) and 98% (Example 4-1) as the temperature of the addition step decreased.

[0279] Figure 32 shows FA manufactured in Examples 5-1 to 5-4 and Comparative Examples 5-1 and 5-2. 0.9 Cs 0.1 PbBr 1.2 I 1.8 This is a diagram showing the luminescence spectrum (a) and photoluminescence quantum yield (PLQY) (b) measured for a solution containing perovskite nanocrystals.

[0280] Figure 33 shows FAPbCl prepared in Examples 6-1 to 6-4 and Comparative Examples 6-1 and 6-2. 1.2 Br 1.8 This is a diagram showing the luminescence spectrum (a) and photoluminescence quantum yield (PLQY) (b) measured for a solution containing perovskite nanocrystals.

[0281] Figure 34 is a drawing showing the luminescence spectrum (a) and photoluminescence efficiency (PLQY) (b) measured for a solution containing FAPbI3 perovskite nanocrystals manufactured in Examples 7-1 to 7-4 and Comparative Examples 7-1 and 7-2.

[0282] As shown in FIGS. 32 to 34, for perovskite nanocrystals of all compositions, it was confirmed that the photoluminescence efficiency of the solution containing perovskite nanocrystals improved as the temperature of the step of adding the precursor solution was lowered from 20°C to 0°C.

[0283] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. A step of preparing a ligand solution containing an organic ligand, an anti-emulsifier and a non-polar solvent; A step of preparing a precursor solution containing a perovskite precursor and a polar solvent; a step of adding the precursor solution to the ligand solution; and Comprising a step of stirring a ligand solution to which the precursor solution is added, The step of adding the precursor solution to the ligand solution is performed at a temperature of 15° C. or less, A method for producing perovskite nanocrystals, wherein the precursor solution comprises a highly coordinated polyhalide metallate.

2. In claim 1, A method for producing perovskite nanocrystals, wherein the coordination number of the above-mentioned highly coordinated polyhalide metallate is 3 or more.

3. In claim 1, A method for producing perovskite nanocrystals, wherein the anti-emulsifier comprises acetone, ethanol, methanol, 1-propanol, 1-butanol, tert-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, benzyl alcohol, benzyl benzoate, benzyl acetate or a combination thereof.

4. In claim 1, A method for producing perovskite nanocrystals, wherein the total concentration of the perovskite precursor in the precursor solution is 0.1 M or more.

5. In claim 1, a method for producing a perovskite nanocrystal, wherein the perovskite nanocrystal is represented by the following chemical formula 1: [Chemical Formula 1] ABX3 (In the above chemical formula 1, A is a monovalent cation, B is a divalent metal cation, and X is a halogen anion).

6. In claim 5, The above A is an organic amidinium ion, an organic ammonium ion, Cs, Rb or a combination thereof, The above B is a divalent cation of Pb, Mn, Cu, Ga, Ge, In, Al, Sb, Bi, Po, Sn, Eu, Yb, Ni, Co, Fe, Cr, Pd, Cd, Ca or Sr or a combination thereof, The above X is Cl - , Br - , I - A method for producing perovskite nanocrystals, wherein the perovskite nanocrystals are a combination of these.

7. In claim 6, The above organic amidinium ion is formamidinium (NH2CH=NH2 + ), guanidinium (NH2C(NH2)=NH2 + ), acetamidinium (NH2C(CH3)=NH2 + ) or a combination thereof.

8. In claim 6, The above organic ammonium ions are methylammonium, ethylammonium, tert-butylammonium, diethylammonium, dimethylammonium, ethane-1.2.-diammonium, imidazolium, npropylammonium, iso-propylammonium, pyrrolidinium, CH(NH2)2. + , C x H 2x+1 (CNH3) + , (CH3NH3) n + , ((C x H 2x+1 ) n NH3) n (CH3NH3) n + , R(NH2)2+ , (C n H 2n+1 NH3) n + , (CF3NH3) + , CF3NH3) n + , ((C x F 2x+1 ) n NH3) n (CF3NH3) n + , ((C x F 2x+1 ) n NH3)2 + , (C n F 2n+1 NH3) n + , (wherein, R is an alkyl group, and n and x are independently integers from 1 to 100), or a combination thereof.

9. In claim 1, A method for producing a perovskite nanocrystal, wherein the organic ligand comprises a carboxylic acid organic ligand, an amine organic ligand or a combination thereof.

10. In claim 9, The above carboxylic acid organic ligands are 4,4'-Azobis(4-cyanovaleric acid), Acetic acid, 5-Aminosalicylic acid, Acrylic acid, L-Aspentic acid, 6-Bromohexanoic acid, Bromoacetic acid, Dichloro acetic acid, Ethylenediaminetetraacetic acid, Isobutyric acid, Itaconic acid, Maleic acid, r-Maleimidobutylic acid. Acid (r-Maleimidobutyric acid), L-Malic acid, 4-Nitrobenzoic acid, 1-Pyrenecarboxylic acid, butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, heptadecanoic acid, octadecanoic acid,A method for producing perovskite nanocrystals comprising oleic acid or a combination thereof.

11. In claim 9, A method for producing perovskite nanocrystals, wherein the above amine organic ligand comprises butylamine, hexylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, oleylamine, N,N-diisopropylethylamine, ethylenediamine, hexamethylenetetramine, methylamine, N,N,N,N-tetramethyleneethylenediamine, triethylamine, diethanolamine, 2,2-(ethylenedioxyl)bis-(ethylamine), 2-methyl-1,5-pentanediamine, 3-methoxytriphenyl-amine, 1,4-phenylenediamine, N,N,N,N-pentamethyl diethylenetriamine, triethylenetetramine, rhodamine, diethylamine, ethylenediamine or a combination thereof.

12. In claim 1, A method for producing perovskite nanocrystals, wherein the step of adding the precursor solution to the ligand solution is performed at a temperature of -15°C or higher and 10°C or lower.

13. A perovskite nanocrystal manufactured by a method according to any one of claims 1 to 12.

14. A perovskite nanocrystal according to claim 13, wherein the photoluminescence efficiency (PLQY) measured for a solution in which the perovskite nanocrystal is dispersed is 85% or more.

15. In claim 13, The above perovskite nanocrystals are perovskite nanocrystals having a photoluminescence (PL) peak in a wavelength range of 525 nm to 535 nm.

16. A perovskite light-emitting device comprising: a first electrode; a hole injection layer positioned on the first electrode; a light-emitting layer positioned on the hole injection layer and comprising perovskite nanocrystals manufactured by a method according to any one of claims 1 to 12; an electron injection layer positioned on the light-emitting layer; and a second electrode positioned on the electron injection layer.

17. In claim 16, A perovskite light-emitting device having an external quantum efficiency (EQE) of 25% or more.

18. In claim 16, A perovskite light-emitting device, wherein the light-emitting layer has an electroluminescence (EL) peak in a wavelength range of 525 nm to 535 nm.

19. In claim 16, A perovskite light-emitting device, wherein the light-emitting layer has an electroluminescence (EL) peak having a full width at half maximum (FWHM) of 30 nm or less.

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