WO2020139043A2 - Perovskite-based blue light-emitting device and manufacturing method therefor - Google Patents

Abstract

The present specification relates to a low-dimensional perovskite-based blue light-emitting device using spacer additive introduction, and a method for manufacturing the blue light-emitting device.

Description

[Correction 08.01.2020 according to Rule 26] 　Perovskite-based blue light emitting device and manufacturing method thereof

The present application relates to a low-dimensional perovskite-based blue light emitting device manufactured through introduction of a spacer additive, and a method of manufacturing the blue light emitting device.

Hybrid halide perovskite-based solar cells showed conversion efficiency (PCE) of more than 20% (in laboratory) in the years following their appearance, and as of July 2018 at the Chinese Academy of Sciences (CAS), the United States National Renewable Energy (NREL) Laboratory) Achieved the highest certified efficiency of 23.3%. The success of these solar cells is due to the unprecedented high absorbance characteristics of the perovskite material and the inexpensive solution processability. In addition, the properties of most of these materials are also suitable for light emitting diodes (LEDs), so the possibility of success of perovskite LEDs (PeLEDs) has been predicted.

Perovskite solar cells are due to their excellent charge carrier mobility and low density of deep trap states. In addition, perovskite exhibits excellent optical properties, including a wide range of color controllability, making it very suitable for luminescent applications. Indeed, bulk and quantum dot perovskites have been a major component in impressive light pumping lasers and light emitting diodes.

Specifically, the rapid development of the organic-inorganic metal halide perovskite means a breakthrough in the next generation thin film optoelectronics. In particular, methylammonium (MA, CH ₃ NH ₃ ) lead iodide (MAPbI ₃ ) perovskite possesses adequate band gap energy, large absorption coefficient and long-distance bipolar photocarrier diffusion. The efforts of several research groups have improved the certified power conversion efficiency (PCE) of perovskite solar cells to 23.3%. However, such a perovskite material lacks long-term stability under ambient operating conditions, and thus, device stability improvement, such as a solar cell using the perovskite, is required.

On the other hand, such a conventional three-dimensional hybrid hybrid perovskite absorbs light well and has excellent charge carrying ability, so it has excellent electrical properties and low fluorescence efficiency. Due to these characteristics, studies related to perovskite solar cells have been actively conducted, but research results related to LED applications have not been reported. However, perovskite LEDs are cheaper than materials used in general LEDs and OLEDs, and have high color purity, so much research is currently underway. Accordingly, it is reported that the first study applied to LED by controlling perovskite is expected to be applicable to various fields such as electronics, medical, and communication devices.

Organometal halide perovskite species exhibit huge bulk crystal domain sizes, rare traps, good mobility, and free carriers at room temperature. These properties support the excellent performance of organometal halide perovskites in charge-separation devices. In devices that rely on forward injection of electrons and holes, such as light emitting diodes (LEDs), good mobility effectively captures non-equilibrium charge carriers by rare nonradiative centers. Contribute to In addition, the lack of bound excitons undermines competition for unintended non-radiative recombination of the intended radiation recombination.

Since excitons in CH ₃ NH ₃ PbI ₃ perovskite have low binding energy (9 meV to 60 meV) [Yang, Y. et al. Observation of a hot-phonon bottleneck in lead-iodide perovskites. Nat. Photon. 10, 53-59 (2016)], at room temperature charge carriers are free instead of forming bound excitons. Thus, the photoluminescence quantum yield (PLQY) of CH ₃ NH ₃ PbI ₃ perovskite is dependent on the excitation intensity, reaching a higher value at high excitation photon fluences predominantly radiative bimolecular recombination. do. Trap-mediated non-radiative recombination predominates under weak excitation, which results in relatively low PLQY.

The present application provides a low-dimensional perovskite-based blue light emitting device manufactured through introduction of a spacer additive and a method of manufacturing the blue light emitting device.

However, the problems to be solved by the present application 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 following description.

A first aspect of the present application provides a light emitting device comprising a quasi-two-dimensional perovskite film comprising a quasi-two-dimensional perovskite unit cell represented by Formula 1 below.

In the second aspect of the present application, a compound of MX ₂ , R ¹ NH ₃ X and BX is mixed in a solvent, and a compound of AX is added to the mixture to form a quasi-two-dimensional perovskite unit cell represented by Chemical Formula 1 below. Provided is a method of manufacturing a light emitting device, including manufacturing:

[Formula 1]

A _α B ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

In Chemical Formula 1,

A and B each independently contain an organoammonium or alkali metal ion, R ¹ contains a linear or branched alkyl group having 1 to 10 carbon atoms, M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ^{2 +} , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , and metal cations selected from the group consisting of , X includes halide anions, n is an integer of 2 or more, and α is the doping content of the A cation, where 0<α≤1.5.

A third aspect of the present application provides a blue light emitting diode, comprising the light emitting device according to the first aspect.

According to the embodiments herein, the crystal structure of the perovskite is controlled by controlling the doping of the A cation (mixing of three different types of organic ammonium cation ligands), through which the low-dimensional perovskite-based blue color is controlled. It is possible to control the properties of the light emitting device. In particular, according to the embodiments of the present application, by controlling the doping amount of an aromatic alkyl ammonium cation when mixing three different types of organic ammonium cation ligands, the physical properties of the low-dimensional perovskite-based blue light emitting device are controlled and luminous efficiency You can maximize it by adjusting.

According to one embodiment of the present application, an easy process, low cost, and efficient device fabrication are possible based on a solution process, and a conventional report of a low-dimensional perovskite-based blue light emitter by controlling a total amount and a relative amount of a mixture ligand It is possible to derive an uncrystallized crystal structure and an improved blue light emission phenomenon.

According to the embodiments of the present application, it is possible to seek a crystal structure diversification by controlling the relative amount of the intercalating insulator ligand, and predict the structure of the resulting crystal by DFT experiments and systematically identify the correlation between the crystal structure and luminescence properties can do.

According to embodiments herein, a bulky insulator alkyl ammonium cation (e.g., aromatic alkyl ammonium cation) is introduced and its doping amount without adjusting the number of layers of the quasi-2 dimensional perovskite (n value) By adjusting the, the emission wavelength band of the low-dimensional perovskite-based blue light emitting device can be controlled from about 480 nm to 500 nm.

1 is a schematic diagram showing a quasi-two-dimensional perovskite unit cell in one embodiment of the present application.

2 is a schematic diagram showing a strategy of a quasi-two-dimensional perovskite comprising a plurality of cationic ligands in one embodiment of the present application.

3A is a graph showing the chemical formula of system 1 perovskite and PL thereof in a strategy of a quasi-dimensional perovskite including a plurality of cationic ligands in one embodiment of the present application.

3B is a schematic diagram showing the (100) orientation of system 1 perovskite in the strategy of a quasi-dimensional perovskite comprising a plurality of cationic ligands in one embodiment of the present application.

4 is a schematic diagram showing the (110) orientation of the system 2 perovskite in the strategy of a quasi-dimensional perovskite comprising a plurality of cationic ligands in one embodiment of the present application.

FIG. 5 is a graph showing a standardized PL of a quasi-dimensional perovskite based light emitting device using Benzyltrimethylammonium bromide (BTABr) additive in one embodiment of the present application.

FIG. 6 shows, in one embodiment of the present application, perovskite film not doped under UV lamp (365 nm), perovskite film 0.2 mole doped with BTA, perovskite film 0.4 mole doped with BTA This is an image showing a film, a perovskite film with 0.6 mole doped BTA, a perovskite film with 0.8 mole doped BTA, and a perovskite film with 1.0 mole doped BTA (from bottom to top).

7 is a graph showing a standardized PL of a quasi-dimensional perovskite based light emitting device using a benzyltrimethylammonium bromide additive in one embodiment of the present application.

8 is, in one embodiment of the present application, a perovskite film doped under UV lamp (365 nm), perovskite film doped with BTA 1.0 mole doped, perovskite doped with BTA 1.2 mole doped This is an image showing a film and a perovskite film with 1.4 moles of BTA doped (from bottom to top).

9 is a graph showing a standardized PL of a quasi-dimensional perovskite-based light emitting device using a phenylethylammonium bromide (PEABr) additive in one embodiment of the present application.

10 is, in one embodiment of the present application, perovskite film is not doped under UV lamp (365 nm), perovskite film doped 0.2 molar PEA, perovskite PEA 0.4 molar doped This is an image showing a film, a perovskite film with 0.6 mole doped PEA, a perovskite film with 0.8 mole doped PEA, and a perovskite film with 1.0 mole doped PEA (from bottom to top).

FIG. 11 is a graph showing UV-vis absorption data of a quasi-dimensional perovskite based light emitting device using a benzyltrimethylammonium bromide additive in one embodiment of the present application.

12 is a graph showing UV-vis absorption data of a quasi-dimensional perovskite-based light emitting device using a phenylethylammonium bromide additive in one embodiment of the present application.

FIG. 13 shows the PL yield of an undoped perovskite film, a perovskite film of 0.4 mole doped PEA, and a perovskite film of 0.8 mole doped PEA, in one embodiment of the present application. It is a graph.

FIG. 14 is a quasi-dimensional perovskite using an phenylethylammonium bromide (PEABr) additive, a benzyltrimethylammonium bromide (BTABr) additive, and an n-hexylammonium bromide (nHABr) additive, respectively, in one embodiment of the present application. It is a graph showing the standardized PL of the base light emitting device (% is mole% relative to the content of R ² NH ₃ ).

15A to 15C, in one embodiment of the present application, each of a phenylethylammonium bromide (PEABr) additive, a benzyltrimethylammonium bromide (BTABr) additive, and a n-hexylammonium bromide (nHABr) additive using a quasi-two-dimensional PEG It is a graph showing the UV-vis absorption data of the lobsky-based light emitting device (% is mol% relative to the content of R ² NH ₃ ).

FIG. 16 is a graph showing the results of X-ray diffraction analysis of a quasi-dimensional perovskite based light emitting device using a phenylethylammonium bromide (PEABr) additive in one embodiment of the present application (% is R ² NH ₃ Mole content relative to).

17A-17E, Grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis of a quasi-dimensional perovskite based light emitting device using a phenylethylammonium bromide (PEABr) additive in one embodiment of the present application. This is a graph that shows: a. 0% PEA; b. 10% PEA; c. 30% PEA; d. 50% PEA; e. 70% PEA (% is mole% relative to the content of R ² NH ₃ ).

18 is a quasi-two-dimensional perovskite using phenylethylammonium bromide (PEABr) additive, benzyltrimethylammonium bromide (BTABr) additive, and n-hexylammonium bromide (nHABr) additive, respectively, in one embodiment of the present application. SEM photograph showing the morphology of the base light emitting device: a. 50% PEA((PEA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ); b. 50% BTA((BTA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ); c. 50% nHA ((nHA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ) (% is mole% relative to the content of R ² NH ₃ ).

FIG. 19 shows the results of Transient absorption (TA) spectroscopy analysis of a quasi-two-dimensional perovskite based light emitting device using a phenylethylammonium bromide (PEABr) additive in one embodiment of the present application: a,e. 0% PEA((nPA) ₂ MA ₂ Pb ₃ Br ₁₀ ); b,f. 10% PEA((PEA) _0.2 (nPA) ₂ MA ₂ Pb ₃ Br _10.2 ); c,g. 30% PEA ((PEA) _0.6 (nPA) ₂ MA ₂ Pb ₃ Br _10.6 ); d,h. 50% PEA((PEA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ) (% is mole% relative to the content of R ² NH ₃ ).

FIG. 20 shows the results of Transient absorption (TA) spectroscopy analysis of a quasi-dimensional perovskite based light emitting device using a benzyltrimethylammonium bromide (BTABr) additive in one embodiment of the present application: a. 0% PEA((nPA) ₂ MA ₂ Pb ₃ Br ₁₀ ); b. 10% BTA ((BTA) _0.2 (nPA) ₂ MA ₂ Pb ₃ Br _10.2 ); c. 30% BTA ((BTA) _0.6 (nPA) ₂ MA ₂ Pb ₃ Br _10.6 ); d. 50% BTA ((BTA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ) (% is mole% relative to the content of R ² NH ₃ ).

FIG. 21 shows the results of Transient absorption (TA) spectroscopy analysis of a quasi-dimensional perovskite based light emitting device using an n-hexylammonium bromide (nHABr) additive, in one embodiment of the present application: a. 0% nHA((nPA) ₂ MA ₂ Pb ₃ Br ₁₀ ), b. 10% nHA((nHA) _0.2 (nPA) ₂ MA ₂ Pb ₃ Br _10.2 ), c. 30% nHA((nHA) _0.6 (nPA) ₂ MA ₂ Pb ₃ Br _10.6 ), d. 50% nHA ((nHA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ) (% is mole% relative to the content of R ² NH ₃ ).

Throughout this specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another device in between. do.

Throughout this specification, when one member is said to be "on" another member, this includes not only the case where one member abuts another member, but also the case where another member exists between the two members.

Throughout the present specification, when a part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

As used herein, the terms “about”, “substantially”, and the like are used in or near the numerical values when manufacturing and material tolerances unique to the stated meanings are presented, to aid understanding of the present application Hazards are used to prevent unreasonable abuse by unconscionable infringers of the disclosures that are accurate or absolute.

The term "step of" or "step of" as used in the present specification does not mean "step for".

Throughout the present specification, the term “combination(s)” included in the expression of the marki form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the marki form, It means to include one or more selected from the group consisting of the above components.

Throughout this specification, the description of “A and/or B” means “A or B, or A and B”.

Throughout the present specification, the description of “alkali metal” is an element belonging to Group 1 of the periodic table and includes lithium (Li), sodium (Na), potassium (K) or rubidium (Rb).

Hereinafter, embodiments and examples of the present application will be described in detail with reference to the accompanying drawings. However, the present application is not limited to these embodiments and examples and drawings.

A first aspect of the present application provides a light emitting device comprising a quasi-2 dimensional perovskite film comprising a quasi-2 dimensional perovskite unit cell represented by Formula 1 below:

[Formula 1]

A _α B ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

In Chemical Formula 1,

A and B each independently contain an organoammonium or alkali metal ion,

R ¹ includes a linear or branched alkyl group having 1 to 10 carbon atoms,

M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

X contains halide anions,

n is an integer of 2 or more,

α is the doping content of the A cation, where 0<α≤1.5.

In one embodiment of the present application, the quasi-two-dimensional perovskite unit cell represented by Chemical Formula 1 may include a quasi-two-dimensional perovskite unit cell represented by Chemical Formula 2:

[Formula 2]

(CNR ³ ₃ ) _α (R ² NH ₃ ) ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

In Chemical Formula 2,

C includes an aryl-alkyl group or a linear alkyl group having 1 to 10 carbon atoms,

R ¹ and R ² each independently includes a linear or branched alkyl group having 1 to 10 carbon atoms,

R ³ includes H or a linear or branched alkyl group having 1 to 10 carbon atoms,

M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

X contains halide anions,

n is an integer of 2 or more,

α is the doping content of the (CNR ³ ₃ ) cation, where 0<α≤1.5.

In one embodiment of the present application, the luminous efficiency of the quasi-two-dimensional perovskite unit cell may be controlled by adjusting the doping content α of the A cation.

In one embodiment of the present application, the emission wavelength band of the quasi-two-dimensional perovskite unit cell may be controlled from 460 nm to 500 nm by adjusting the doping content α of the A cation. More specifically, by controlling the doping content α of the A cation, the emission wavelength band of the quasi-two-dimensional perovskite unit cell is controlled from 480 nm to 500 nm, which may indicate blue emission.

In one embodiment of the present application, the light emitting device including the quasi-two-dimensional perovskite is an aromatic alkylammonium cationic ligand or an aliphatic alkylammonium cationic ligand in a low-dimensional perovskite using an aliphatic alkylammonium cationic ligand, For example, it can be prepared by doping benzylmethylammonium (Benzyltrimethylammonium, BTA), phenylethylammonium (PEA) or n-hexylammonium (HA) cations.

In one embodiment of the present application, the light-emitting device including the quasi-two-dimensional perovskite controls the perovskite crystal structure through mixing of the three different types of organic ammonium cation ligands, through which The properties of the blue light-emitting body can be controlled. In particular, in one embodiment of the present application, when mixing three different types of organoammonium cation ligands, A cation (CNR ³ ₃ cation), for example, benzylmethylammonium (Benzyltrimethylammonium, BTA), phenylethylammonium (Phenylethylammonium, PEA) or n-hexylammonium (HA) cation to control the crystal structure of the perovskite by controlling the amount of doping, thereby controlling the properties of the quasi-two-dimensional perovskite-based light emitting device It is possible to control, adjust its emission wavelength to the blue wavelength and maximize the emission efficiency.

Referring to Figure 1 of the present application, the quasi-two-dimensional perovskite using propylamine and methylamine of the prior art as an A-site cationic ligand may be represented as (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3). In the light emitting device according to one embodiment of the present application, benzylmethylammonium (BTA), phenylethylammonium (PEA), or n-hexylammonium (HA) cation is introduced into the structure as an additive. , A quasi-two-dimensional perovskite unit cell represented by Chemical Formula 1 can be manufactured, and when manufactured, a light emitting device can be adjusted to a blue wavelength and maximize the luminous efficiency.

2 to 5, when doping the additive of BTABr to quasi-two-dimensional perovskite (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3), (BTA) _x (nPA) _2-x It can be system 1 of MA ₂ Pb ₃ Br ₁₀ or system 2 of (RA ⁺ ) _y (nPA) ₂ MA ₂ Pb ₃ Br _10+y . The light emitting device according to the embodiment of the present application represents the system 2. The quasi-two-dimensional perovskite through the system 1 is a model in which two types of spacers are mixed within a total of 2 moles by replacing the nPA spacer with BTA, and when its PL is measured, wavelength shift is not found (Fig. 3a). In addition, when looking at the orientation of System 1, it shows (100) orientation (FIG. 3B). On the other hand, System 2 showing a light emitting device according to one embodiment of the present application is a model in which three spacers having different chemical properties are added in a total amount of more than 2 moles, and a quasi-two-dimensional BTA spacer has nPA as a basic configuration. As additionally introduced into the perovskite, it can be confirmed that the emission wavelength shifts to a short wavelength in proportion to the introduced amount (FIG. 5). In addition, when looking at the orientation of the system 2, it has a (110) orientation and is different from the system 1 (FIG. 4).

In one embodiment of the present application, the quasi-two-dimensional perovskite unit cell may exhibit blue light emission and have (110) orientation. In addition, it may be to induce blue-shift (PL) of the photoluminescence (PL) emission peak wavelength of the light emitting device by controlling the content of the A cation (CNR ³ ₃ cation). Specifically, since the quasi-two-dimensional perovskite unit cell has (110) orientation, it is advantageous to exhibit blue light emission, and the crystallinity inside the thin film increases, so that it is aligned in the vertical orientation, so that the recombination of excitons is advantageous. The degree of charge transfer through the quasi-two-dimensional perovskite is excellent.

In one embodiment of the present application, the A cation may include one or more selected from benzyltrimethylammonium, phenylethylammonium and n-hexylammonium, but is not limited thereto.

In one embodiment of the present application, C is a phenyl-C _1-6 alkyl group, R ¹ is a C _1-6 alkyl group, R ² is a C _1-6 alkyl group, and M is Pb ²⁺ , The X is an iodine anion, the n is an integer of 2 or 3, and the α may be 0.6 to 1.

In one embodiment of the present application, without adding Cs to the A-position cation site of the perovskite, a luminous efficiency of about 88% can be obtained at 485 nm. Specifically, the prior art increases the luminous efficiency by adding Cs to the A-position cation site of the perovskite, and induced blue-shift of the PL emission peak wavelength, according to an embodiment of the present application. The light emitting device obtains a luminous efficiency of 62.5% at 480 nm without adding Cs by adding at least one selected from benzyltrimethylammonium, phenylethylammonium and n-hexylammonium to the A-position cation site, and at the same time the peak emission wavelength of PL emission. Blue-shift can be induced.

In one embodiment of the present application, the light-emitting device, PLQY (Photoluminescence quantum yield) may exhibit a high value of about 93% at 497 nm, about 88% at 485 nm, PLQY by additionally introducing cations such as Cs Can be further increased.

In one embodiment of the present application, the total number of moles of the three types of organic ammonium cations included in the quasi-dimensional perovskite unit cell is greater than n+1, for example, the benzylmethylammonium (Benzyltrimethylammonium, BTA), phenylethylammonium (Phenylethylammonium, PEA) or n-hexylammonium (n-hexylammonium, HA) cation, such as the doping amount of the organic ammonium cation is greater than α, the number of moles of the three alkylammonium cations is (n + 1)+α. In addition, the number of moles of halide X included in the quasi-dimensional perovskite unit cell is benzylmethylammonium (BTA), phenylethylammonium (PEA) or n-hexylammonium (n-) at 3n+1. Hexylammonium, HA) The doping amount of an organic ammonium cation, such as cation, can be as large as 3 n+1+α.

In one embodiment of the present application, the light emitting device may have an emission wavelength of about 460 nm to about 500 nm, but is not limited thereto. More specifically, the emission wavelength can be adjusted from about 480 nm to about 500 nm.

The second aspect of the present application is to mix a compound of MX ₂ , R ¹ NH ₃ X and BX in a solvent, and add a compound of AX to the mixture to give a quasi-two-dimensional perovskite unit cell represented by Formula 1 below. It provides a method of manufacturing a light emitting device, comprising manufacturing:

[Formula 1]

A _α B ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

In Chemical Formula 1,

A and B each independently contain an organoammonium or alkali metal ion,

R ¹ includes a linear or branched alkyl group having 1 to 10 carbon atoms,

M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

X contains halide anions,

n is an integer of 2 or more,

α is the doping content of the A cation, where 0<α≤1.5.

In one embodiment of the present application, the quasi-two-dimensional perovskite unit cell represented by Chemical Formula 1 may include a quasi-two-dimensional perovskite unit cell represented by Chemical Formula 2:

[Formula 2]

(CNR ³ ₃ ) _α (R ² NH ₃ ) ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

In Chemical Formula 2,

C includes an aryl-alkyl group or a linear alkyl group having 1 to 10 carbon atoms,

R ¹ and R ² each independently includes a linear or branched alkyl group having 1 to 10 carbon atoms,

R ³ includes H or a linear or branched alkyl group having 1 to 10 carbon atoms,

M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

X contains halide anions,

n is an integer of 2 or more,

α is the doping content of the (CNR ³ ₃ ) cation, where 0<α≤1.5.

A method of manufacturing a light emitting device according to one embodiment of the present application may further include manufacturing a quasi-two-dimensional perovskite film by coating the quasi-two-dimensional perovskite unit cell on a base material. .

In one embodiment of the present application, the luminous efficiency of the quasi-two-dimensional perovskite unit cell may be controlled by adjusting the doping content α of the A cation.

In one embodiment of the present application, the emission wavelength band of the quasi-two-dimensional perovskite unit cell may be controlled from 460 nm to 500 nm by adjusting the doping amount α of the A cation. More specifically, the emission wavelength band of the quasi-two-dimensional perovskite unit cell may be controlled from 480 nm to 500 nm by adjusting the doping amount α of the A cation.

In one embodiment of the present application, an easy process, low cost, and efficient fabrication of a perovskite-based blue light emitting device based on a solution process are possible, and the total amount of the three different organic ammonium mixture ligands and their relative By controlling the amount, it is possible to derive a perovskite crystal structure that has not been previously reported, thereby improving the blue light emission phenomenon.

In one embodiment of the present application, the synthetic yield of the quasi-two-dimensional perovskite unit cell may be about 100%.

In one embodiment of the present application, by controlling the relative amount of the intercalating insulator ligand, diversification of the crystal structure can be sought. In addition, the structure of the derived crystal can be predicted by DFT experiment, and the correlation between the crystal structure and luminescence properties can be systematically identified.

A third aspect of the present application provides a blue light emitting diode, comprising the light emitting device according to the first aspect.

In the first to third aspects, contents that may be common to each other may be applied to all of the first side, second side, and third side even if the description is omitted.

Hereinafter, the present application will be described in more detail by examples, but the present application is not limited thereto.

1. Manufacture of low-dimensional perovskite-based blue light emitter

1-1. Preparation of perovskite solution precursor

Dimethylsulfoxide (DMSO) 1 mL of lead bromide [lead(II) bromide, PbBr ₂ ]: methylammonium bromide (MABr): n-propylammonium bromide (nPApropylr bromide, nPABr) 3: Dissolve in a molar ratio of 2:2 and alkylammonium additives such as phenylethylammonium bromide (PEABr), benzyltrimethylammonium bromide (BTABr) or n-hexylammonium bromide (nHABr) bromide additives) were added in molar ratios of 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, and 1.4. Then, the precursor solution was stirred for 30 minutes at room temperature.

1-2. Perovskite thin film production

After washing the glass substrate through acetone, isopropyl alcohol, distilled water (DI water) for 30 minutes each by ultrasonic treatment, and then applying a perovskite precursor solution, spin-coating under conditions of 5000 rpm and 70 seconds. 100 μL of chloroform was dropped 35 seconds after the start of spin-coating. After the spin-coating program set time was over, it was annealed at 90°C for 5 minutes.

2. Characterization

2-1. PL(Photoluminescence) Measurement

(nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3) When the amount of PEABr, BTABr, and nHABr is added to the low-dimensional perovskite luminous material, respectively, as an additive, the amount is increased from 507 nm to 455 nm. Up to about 5 nm, the PL emission peak wavelength was blue-shifted (Fig. 2, Fig. 6, and Fig. 14).

When BTABr spacer additive was continuously added, a clear precursor solution was obtained at room temperature up to a 1.0 mole ratio, but BTABr precipitate was formed at room temperature when added at a 1.2 to 1.4 mole ratio. That is, when the BTABr spacer additive is mixed up to 1.0 mol, it can be predicted that the photoluminescence quantum efficiency will be excellent when manufactured as a thin film. Subsequently, when the precipitate was filtered using a hydrophobic filter and spin-coated on a glass substrate, a blue-shifting phenomenon was observed up to about 470 nm, as in FIGS. 5 and 6 (FIGS. 7 and 8 ).

Even when the PEABr additive was added instead of the BTABr additive, a very similar degree of blue-shifting from 507 nm (sample without additive) to 485 nm (sample with 0.8% mole additive) was caused by the same amount of additive. Appeared (FIGS. 9 and 10 ). As a difference from the BTABr additive, the low-dimensional perovskite containing PEABr additive showed higher photoluminescence quantum efficiency (PLQY) (Table 1).

2-2. PLQY(Photoluminescence quantum yield) measurement

[Table 1]

[Table 2]

Table 1 shows the PLQY of the quasi-two-dimensional perovskite film doped with BTABr, and the quasi-two-dimensional perovskite film doped with PEABr. Through Table 1, BTABr doped quasi-two-dimensional perovskite film, and PEABr doped quasi-two-dimensional perovskite film are both shifted to the blue wavelength compared to the case where the doping (green wavelength) I could confirm that. In addition, BTABr 1 doped quasi-dimensional perovskite film in BTABr 1 mole doped photoluminescence quantum efficiency is maintained similar to the case where the doped BTABr 1 molar doping is excellent in being used as the most blue emitter I could confirm. In addition, PEABr-doped quasi-two-dimensional perovskite films can be confirmed that the overall light emission quantum efficiency is excellent, in particular, 0.4 mol and 0.8 mol of PEABr was found to have the best light emission quantum efficiency effect ( Values of 0.6 molar doping have errors). In addition, when a 50 mol% PEA sample ((PEA) ₁ (nPA) ₂ MA ₂ Pb ₃ Br ₁₁ ) was prepared as a thin film, photoluminescence quantum efficiency of 62.5% was obtained at an excitation wavelength of 480 nm.

Table 2 shows the PL Full-width at Half maximum (PL FWHM) of the quasi-two-dimensional perovskite film doped with BTABr, and the quasi-two-dimensional perovskite film doped with PEABr. (color purity) can be confirmed. The PL FWHM difference is shown to be very small compared to the case where BTABr doped quasi-two-dimensional perovskite film, and PEABr doped quasi-two-dimensional perovskite film were both not doped, both films It was confirmed that it has excellent color purity.

2-3. Measurement of absorbance (Uv-vis absorption)

When the BTABr additive, PEABr additive, and nHABr additive are added in the same amount (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ in the wavelength region corresponding to 475 nm or more, the n≥ layer (475 nm) having the narrowest band gap The formation of low-dimensional perovskite was similarly suppressed (FIGS. 11, 12, 15A, 15B and 15C). Through this, it can be explained that even though different types of alkylammonium bromide additives are added in FIGS. 5 and 9, they show the same degree of blue-shifting when the amounts are the same. The salient difference between the two additives is the intensity of the excitonic absorption peak at 428 nm (n=2) and 443 nm (n=3). When a PEABr additive was added compared to the BTABr additive, the formation of a low-dimensional perovskite having n=2 and n=3 is remarkable. Through this, the luminous efficiency of Table 1 can be explained, and the formation of a low-dimensional perovskite of n≥4 layer (475 nm) is similarly suppressed, while the quasi-two-dimensional perovskite is maintained while emitting blue light. You can see that it works.

2-4. X-ray diffraction analysis

16, the more additives are added to the low-dimensional perovskite emitter material having the molecular formula of (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3), the more rapidly the perovskite thin film surface becomes amorphous. Can be observed. As a surface analysis, there was a limitation in the analysis of crystals, so a grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis technique was used.

(nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3) PEABr doped into a low-dimensional perovskite emitter having a molecular formula is increased from 0.6 mol, which is 30 mol%, to the crystallinity inside the thin film, and is perpendicular to the substrate. It can be confirmed that it is aligned, and it can be seen that the most vertical alignment is performed well at 1 mole, which is 50 mol%. However, if PEABr is added very much, it is important to adjust the content appropriately since the amorphization proceeds.

2-5. Grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis

17A to 17E, the perovskite thin film in which PEABr is increasingly introduced into the low-dimensional perovskite emitter material having the molecular formula of (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3) is used as GIWAXS. When analyzed, it can be observed that the crystallinity of the (110) orientation increases inside the thin film. 17C, when 1.0 mole of PEABr 50% was doped, it was confirmed that the crystallinity of the (110) orientation was increased inside the thin film, and the orientation was well achieved up to the lower limit of 0.6 moles and the upper limit of 1.4 moles based on 1 mole. can confirm.

2-6. Grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis

Referring to FIG. 18, when BTABr was additionally introduced into a low-dimensional perovskite luminous material having a molecular formula of (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3), tertiary methyl functional group was added with ammonium cations and bromine. It can be confirmed that a very irregular thin film is formed because it interferes with the ionic bond between the anions (FIG. 18B). In addition, when n-HABr was additionally introduced, pinholes were formed on the surface of the thin film due to high crystallinity due to the increase in crystallinity due to the interaction between long chain chain molecules (Fig. 18c), when PEABr was additionally introduced, A uniform thin film without pinholes was formed (Fig. 18A). This satisfies the conditions for application as a light emitting layer of an LED device. Through this, when 1 mole of BTABr 50%, a thin film without pinholes, was added, it was confirmed that it is suitable for use as the most blue light emitter.

2-7. Transient absorption (TA) analysis

19 to 21, when the additives of BTABr, PEABr, and nHABr are introduced into a low-dimensional perovskite emitter material having a molecular formula of (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3), all are blue. Although luminescence was induced, it was confirmed that PEA ⁺ was most advantageous in forming m=3 excitons as a result of TA analysis (FIG. 19 ). In order to design a blue perovskite material having high luminous efficiency, the generated free energy for the formation of m=3 excitons must not have a large difference between the existing (100)-oriented n=3 excitons generated free energy. When the thin film of the Skyt precursor solution was prepared by a solution process, it should be a uniform shape without pinholes on the surface, so the additives of BTABr, PEABr, and nHABr of the example were introduced (nPA) ₂ MA ₂ Pb ₃ Br ₁₀ (n=3 It was confirmed that the low-dimensional perovskite emitter having a molecular formula of) is suitable for use as a blue emitter.

The above description of the present application is for illustrative purposes, and those skilled in the art to which the present application pertains will understand that it is possible to easily modify to other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present application is indicated by the claims below, rather than the detailed description, and it should be interpreted that all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present application.

Claims (13)

1. A light emitting device comprising a quasi-2 dimensional perovskite film comprising a quasi-2 dimensional perovskite unit cell represented by Formula 1 below:

   [Formula 1]

   A _α B ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

   In Chemical Formula 1,

   A and B each independently contain an organoammonium or alkali metal ion,

   R ¹ includes a linear or branched alkyl group having 1 to 10 carbon atoms,

   M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

   X contains halide anions,

   n is an integer of 2 or more,

   α is the doping content of the A cation, where 0<α≤1.5.
2. According to claim 1,

   The quasi-two-dimensional perovskite unit cell represented by Chemical Formula 1 includes a quasi-two-dimensional perovskite unit cell represented by Chemical Formula 2 below:

   [Formula 2]

   (CNR ³ ₃ ) _α (R ² NH ₃ ) ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

   In Chemical Formula 2,

   C includes an aryl-alkyl group or a linear alkyl group having 1 to 10 carbon atoms,

   R ¹ and R ² each independently includes a linear or branched alkyl group having 1 to 10 carbon atoms,

   R ³ includes H or a linear or branched alkyl group having 1 to 10 carbon atoms,

   M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

   X contains halide anions,

   n is an integer of 2 or more,

   α is the doping content of the (CNR ³ ₃ ) cation, where 0<α≤1.5.
3. According to claim 1,

   The luminous efficiency of the quasi-two-dimensional perovskite unit cell is controlled by adjusting the doping content α of the A cation.
4. According to claim 1,

   By adjusting the doping content α of the A cation, the emission wavelength band of the quasi-two-dimensional perovskite unit cell is controlled from 480 nm to 500 nm.
5. According to claim 1,

   The quasi-two-dimensional perovskite unit cell exhibits blue light emission and has (110) orientation.
6. According to claim 1,

   The A cation is one of benzyl trimethyl ammonium, phenyl ethyl ammonium, and one or more selected from n-hexyl ammonium, the light emitting device.
7. According to claim 2,

   The C is a phenyl-C _1-6 alkyl group, the R ¹ is a C _1-6 alkyl group, the R ² is a C _1-6 alkyl group, the M is Pb ²⁺ , the X is an iodine anion, and the n is an integer of 2 or 3, wherein α is 0.6 to 1, the light emitting device.
8. Mix the compounds of MX ₂ , R ¹ NH ₃ X and BX in a solvent,

   To prepare a quasi-two-dimensional perovskite unit cell represented by the following formula (1) by adding the compound of AX to the mixture

   A method of manufacturing a light emitting device comprising:

   [Formula 1]

   A _α B ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

   In Chemical Formula 1,

   A and B each independently contain an organoammonium or alkali metal ion,

   R ¹ includes a linear or branched alkyl group having 1 to 10 carbon atoms,

   M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

   X contains halide anions,

   n is an integer of 2 or more,

   α is the doping content of the A cation, where 0<α≤1.5.
9. The method of claim 8,

   The quasi-two-dimensional perovskite unit cell represented by Chemical Formula 1 includes a quasi-two-dimensional perovskite unit cell represented by Chemical Formula 2 below:

   [Formula 2]

   (CNR ³ ₃ ) _α (R ² NH ₃ ) ₂ (R ¹ NH ₃ ) _n-1 M _n X _3n+1+α ;

   In Chemical Formula 2,

   C includes an aryl-alkyl group or a linear alkyl group having 6 to 10 carbon atoms,

   R ¹ and R ² each independently includes a linear or branched alkyl group having 1 to 10 carbon atoms,

   R ³ includes H or a linear or branched alkyl group having 1 to 10 carbon atoms,

   M is Pb ²⁺ , Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Yb ²⁺ , Sn ²⁺ , Ge ²⁺ , And metal cations selected from the group consisting of combinations thereof,

   X contains halide anions,

   n is an integer of 2 or more,

   α is the doping content of the (CNR ³ ₃ ) cation, where 0<α≤1.5.
10. The method of claim 8,

    A method of manufacturing a light-emitting device further comprising coating the quasi-two-dimensional perovskite unit cell on a base material to produce a quasi-two-dimensional perovskite film.
11. The method of claim 8,

    A method of manufacturing a light emitting device, wherein the luminous efficiency of the quasi-two-dimensional perovskite unit cell is controlled by controlling the doping content α of the A cation.
12. The method of claim 8,

    By adjusting the doping amount α of the A cation, the emission wavelength band of the quasi-two-dimensional perovskite unit cell is controlled from 480 nm to 500 nm, the light emitting device.
13. A blue light emitting diode comprising the light emitting device according to claim 1.

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