CN109728202B

CN109728202B - Flexible red light electro-injection light-emitting device based on metal halide perovskite light-emitting layer

Info

Publication number: CN109728202B
Application number: CN201811551566.8A
Authority: CN
Inventors: 边继明; 王敏焕; 刘洪珠; 冯昱霖; 董庆顺; 史彦涛
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2018-12-19
Filing date: 2018-12-19
Publication date: 2020-07-24
Anticipated expiration: 2038-12-19
Also published as: CN109728202A

Abstract

The invention provides a flexible red light electro-injection light-emitting device based on a metal halide perovskite light-emitting layer. The invention relates to a flexible red light electro-injection light-emitting device based on a metal halide perovskite light-emitting layer, which comprises an anode layer, a hole transport layer, a perovskite light-emitting layer, an electron transport layer and a flexible substrate which are sequentially arranged; the anode layer adopts Au, the hole transport layer adopts Spiro-OMeTAD, and the perovskite luminescent layer adopts Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The electron transmission layer is made of amorphous discontinuous electron transmission material SnO₂The flexible substrate adopts ITO/PEN. The preparation method of the flexible red light electro-injection luminescent device of the halide perovskite luminescent layer is simple and easy to implement and low in cost, and the prepared flexible red light electro-injection luminescent device effectively solves the problem of bending stability of the flexible perovskite device.

Description

Flexible red light electro-injection light-emitting device based on metal halide perovskite light-emitting layer

Technical Field

The invention relates to a semiconductor material light-emitting technology, in particular to a flexible red light electric injection light-emitting device based on a metal halide perovskite light-emitting layer.

Background

The perovskite type solar cell has excellent material properties including high-efficiency charge extraction capacity, continuously adjustable optical band gap, carrier diffusion length of 100-1000 nm, exciton service life of 100ns, low processing temperature and the like, for perovskite type solar cells (PSCs), the certified conversion efficiency (PCE) is rapidly improved to more than 23% in less than five years, the property is equivalent to that of the most advanced modern monocrystalline silicon solar cells which have been developed for more than 50 years, the high-efficiency solar cell material is also an ideal luminescent material according to the balance principle of the Shockley-Quieiser formula, and the perovskite type organic metal halide perovskite based material can obtain strong electroluminescence (E L) spectrum and can prepare the perovskite type light emitting diode (Pe-L ED) with adjustable emission spectrum, particularly the Pe-L ED is rapidly developed in the fields of red, green and blue light.

The present invention relates to a method for manufacturing a flexible device, and more particularly, to a method for manufacturing a flexible device, which comprises forming a flexible substrate having a plurality of functional layers, forming a plurality of layers of the flexible substrate, and forming a plurality of layers of the flexible substrate.

Currently, most flexible devices on organo-metal halide perovskites (including PSC and Pe-L ED) comprise a multilayer structure, usually comprising a perovskite layer for the active layer, sandwiched between a hole transport layer (HT L) and an electron transport layer.

Disclosure of Invention

The present invention aims to address the problem of poor bending stability of flexible devices over current organo-metal halide perovskites (including PSC and Pe-L ED), and proposes a flexible red-light electro-injection light emitting device based on a metal halide perovskite light emitting layer, which has excellent bending stability.

In order to achieve the purpose, the invention adopts the technical scheme that: a flexible red light electro-injection light-emitting device based on a metal halide perovskite light-emitting layer comprises an anode layer, a hole transport layer, a perovskite light-emitting layer, an electron transport layer and a flexible substrate which are sequentially arranged; the anode layer adopts Au, the hole transport layer adopts Spiro-OMeTAD, and the perovskite luminescent layer adopts Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The electron transmission layer is made of amorphous discontinuous electron transmission material SnO₂The flexible substrate adopts ITO/PEN.

The invention also discloses a preparation method of the flexible red light electro-injection light-emitting device based on the metal halide perovskite light-emitting layer, which comprises the following steps: an electron transmission layer (amorphous discontinuous electron transmission material SnO) is sequentially grown on a flexible conductive ITO/PEN substrate by adopting a full low-temperature solution method₂) Perovskite luminescent layer [ Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃Mixed perovskite thin film material]And a hole transport layer (Spiro-OMeTAD), and gold electrodes are evaporated on the hole transport layer to prepare the flexible red light electro-injection light-emitting device (Pe-L ED) based on the metal halide Perovskite light-emitting layer.

Further, amorphous non-continuous electron transport material SnO₂(also called SnO₂Sol-gel) was prepared as follows: SnCl₂·2H₂Dissolving O in absolute ethyl alcohol to obtain SnCl₂·2H₂Placing an absolute ethyl alcohol solution with the O concentration of 0.10-0.12 g/1m L in a container, refluxing for 2.5-3.5 h at 70-80 ℃, aging for 2.5-3.5 h at 20-40 ℃ (preferably 30 ℃), and placing at room temperature for 1-3 d (preferably 2d) to obtain light yellow sol, namely the amorphous discontinuous electron transport material SnO₂。

Further, perovskite precursor liquid [ Cs ] is mixed_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃Mixed perovskite thin film material]The preparation method comprises the following steps:

step 1: firstly, the mass ratio is 0.645-0.655: 0.102 to 0.104: 0.218 to 0.225: 0.024-0.032 PbI₂、PbBr₂、HC(NH₂)₂I (FAI) and CH₃NH₃Br (MABr), dissolving the mixture in a mixed solvent of DMF (N, N-dimethylformamide) and DMSO (dimethyl sulfoxide) in a volume ratio of 0.7-0.9: 0.1-0.3, and stirring at 55-65 ℃ for 0.5-1.5 h to obtain a precursor I; the mass ratio of the mixture to the mixed solvent is 760-800: 0.9 to 1.1;

step 2, dissolving the CsI in DMSO to obtain a DMSO solution with the CsI concentration of 0.38-0.4 mg/1u L, adding the DMSO solution into a glass container, and stirring for 0.5-1.5 h at the temperature of 55-65 ℃ to obtain a precursor II;

and step 3: and mixing the first precursor and the second precursor according to the volume ratio of 0.03-0.07: 0.93-0.97 to prepare the mixed perovskite precursor solution.

Further, the preparation method of the hole transport layer Spiro-OMeTAD solution comprises the following steps of adding a hole transport material Spiro-OMeTAD (CuPc-DMP) into a mixed solution of a lithium bis (trifluoromethanesulfonylimide) (L i-TFSI) solution (520mg/1m L acetonitrile), 4-tert-butylpyridine (TBP), a Co salt (such as cobalt dichloride) solution (300mg/1m L acetonitrile) and chlorobenzene, and uniformly stirring to prepare the Spiro-OMeTAD solution, wherein the volume ratio of L i-TFSI solution, TBP, Co salt solution and chlorobenzene in the mixed solution is 0.018-0.019: 0.029-0.031: 0.017-0.019: 0.92-0.94.

Further, the preparation of the flexible red light electric injection light-emitting device comprises the following steps: the method for growing the electron transport layer on the flexible conductive ITO/PEN substrate comprises the following steps: preparing the electron transmission layer by adopting a single-step spin coating method, starting a spin coater, setting 3000 revolutions for 30s, placing an ITO/PEN flexible substrate on a rotary bracket of the spin coater, fixing the ITO/PEN flexible substrate by vacuum adsorption, starting the spin coater, and taking the prepared amorphous discontinuous electron transmission material SnO₂(e.g., 60-80 u L) rotated at a distanceDropping the sample on a rotating ITO/PEN flexible substrate at a stable constant speed within 20-22 s after the rotation is finished, moving the sample to a hot plate at 100 ℃ after a spin coater stops rotating, annealing for 0.5-1.5 h, and then putting the sample into ozone for treatment for 20-30 min;

growing perovskite luminescent layer [ Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃Mixed perovskite thin film material]Uniformly coating a mixed perovskite precursor liquid on a sample subjected to ozone treatment, starting a spin coater, wherein the spin coating setting is that firstly 1000 is rotated for 10s and then 5000 is rotated for 30s, taking a trifluorotoluene solution (such as 100-140 u L), quickly dripping the solution onto the rotating sample between 14-16 s from the rotation end of the spin coater, moving the sample onto a hot plate at 85 ℃ after the spin coater stops rotating, annealing for 30-50 min, and then moving the sample into a vessel to naturally cool to room temperature;

spin coating hole transport layer (spiral-OMeTAD) and evaporating gold electrode to obtain Au/spiral-OMeTAD/Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃/SnO₂A flexible red light electron injection light emitting device based on a metal halide perovskite light emitting layer of/ITO/PEN, the structure of which is shown in figure 1.

Compared with the prior art, the flexible red light electro-injection luminescent device based on the metal halide perovskite luminescent layer and the preparation method thereof have the following advantages:

1) the invention relates to a flexible red light electro-injection luminescent device, which is characterized in that an amorphous discontinuous electron injection layer (SnO) is sequentially grown on a flexible conductive ITO/PEN substrate by adopting a full low-temperature solution method_x) The flexible red light electric injection light-emitting device (also called flexible Perovskite light-emitting device, Perovskite light emitting diode, hereinafter abbreviated as Pe-L ED) is prepared by mixing a cationic lead halide Perovskite light-emitting layer and a hole injection layer (Spiro-OMeTAD). The Pe-L ED prepared by the invention detects obvious red electroluminescence (E L) from the flexible Pe-L ED under the forward bias of room temperature, which is consistent with the photoluminescence (P L) spectrum and the optical band gap of the Perovskite light-emitting layer, and the Pe-L ED flexible device shows that the flexible Pe-L ED has the advantages of good light emission, good light emission and good light emission performanceExcellent mechanical bending durability, amorphous SnO_xThe soft interface between the electron injection layer and the mixed perovskite layer greatly contributes to the excellent bending resistance of the Pe-L ED, the bending angle reaches 5 pi/4 after 2000 times of harsh bending cycles, and the E L performance of the device is not changed.

2) The invention creatively introduces amorphous discontinuous SnO₂The electronic transmission layer with excellent mechanical property and chemical stability is prepared at low temperature, a high-entropy interface is provided, and the problem of bending stability of the flexible perovskite device is solved. Amorphous discontinuous SnO₂The electronic transmission layer has the unique advantages of low-temperature preparation (-100 ℃), good band gap matching degree, high carrier transmission efficiency, excellent mechanical property and chemical stability far exceeding those of organic polymers, and simultaneously provides a high-entropy interface between ET L and the active layer, so that the interface is insensitive to bending, and the bending stability of the flexible device is greatly improved.

3) The preparation method of the flexible red light electro-injection light-emitting device based on the metal halide perovskite light-emitting layer is simple and easy in process and low in cost.

Drawings

FIG. 1 shows Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃Cross-sectional SEM images of the base leds;

FIG. 2 shows Cs measured in a dark state at room temperature_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃A current density-voltage characteristic diagram of the base light emitting diode;

FIG. 3 shows Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The P L spectrum of the LED when it is not bent or bent has a bending angle of 3 pi/4 and effective area of 0.16cm²；

FIG. 4 shows Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The base LED is bent 200, 400, 600, 8The P L contrast spectra of 00 times and 1000 times have a bending angle of 3 pi/4 and an effective area of 0.16cm²；

FIG. 5 is a comparison of E L spectra of fresh samples and samples tested after being bent 2000 times, the bending angle being 3 π/4 and the effective area being 0.16cm²。

Detailed Description

The invention is further illustrated by the following examples:

example 1

SnO₂Preparation of sol-gel: 2.79g SnCl are weighed out₂·2H₂Refluxing O in 25m L anhydrous ethanol at 78 deg.C for 3h, aging at 30 deg.C for 3h, and standing at room temperature for 2d to obtain light yellow sol SnO₂And (3) sol.

The method for mixing the perovskite precursor liquid comprises the following steps: the mixed perovskite precursor is prepared by adopting a two-step method. A: firstly 507.7mg of PbI₂、80.7mg PbBr₂、172mg HC(NH₂)₂I (FAI) and 22mg CH₃NH₃Br (MABr) was mixed with DMF (N, N dimethylformamide) and DMSO (dimethyl sulfoxide) (4:1, volume ratio) and dissolved in 1m L solvent B194.9 mg CsI was dissolved in 500u L DMSO, both solutions were stirred at 60 ℃ for 1h, then precursor B was added to precursor A at a volume ratio of 1:19, the mixed precursors were stirred at 60 ℃ for 1 h.

The preparation method of the Spiro-OMeTAD solution comprises the steps of weighing 80mg of the Spiro-OMeTAD (CuPc-DMP) as the hole transport material, 20u L L i-TFSI (520mg/1m L acetonitrile), 30u L TBP and 20u L Co salt acetonitrile solution (300mg/m L) to be dissolved in 1m L chlorobenzene, and uniformly mixing and stirring the mixture.

Example 2:

the embodiment discloses a flexible red light electro-injection light-emitting device based on a metal halide perovskite light-emitting layer, which comprises the following preparation steps:

the substrate is made of PEN/ITO which is flexible and bendable and has a layer of ITO on the surface. SnO prepared by example 1₂Sol gel, mixed perovskite precursor solution and Spiro-OMeTAD solution.

(1) Before preparing the electron transport layer, 2.5 × 2.5.5 cm was first taped²Is flexible and bendable,Selectively covering a PEN/ITO substrate with a layer of ITO grown on the surface, etching with zinc powder and 2M diluted hydrochloric acid, and wiping off residual zinc powder with cotton. Ultrasonic cleaning with detergent, ultrapure water, acetone, and ethanol for 30 min. And (4) after the washed glass is dried, treating for 60min by using ultraviolet-ozone cleaning equipment, and storing in a dust-free environment for later use.

(2) Preparation of amorphous non-continuous SnO by adopting single-step spin coating process₂Starting the spin coater, placing PEN flexible substrate at 3000 r/30 s, adsorbing, starting the spin coater, and collecting 70u L prepared SnO₂And (3) stably and uniformly dropping the sol-gel on the rotating substrate within 20-22 s from the end of rotation, stopping the rotation of the spin coater, moving the sample to a hot plate at 100 ℃, annealing for 1h, and then putting the sample into ozone for treatment for 20-30 min.

(3)Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The mixed perovskite layer is prepared by adopting a single-step dropwise adding anti-solvent method for spin coating, namely, a solution precursor is uniformly coated on a sample which is treated by ozone, a spin coating machine is started, the spin coating setting conditions are that firstly 1000 is rotated for 10s, then 5000 is rotated for 30s, 120u L trifluorotoluene solution is taken, the solution is rapidly dripped on the rotating sample within 14-16 s from the rotation end of the spin coating machine, after the spin coating machine stops rotating, the sample is moved to a hot plate at 85 ℃, and after annealing is carried out for 40min, the sample is moved to a vessel and is naturally cooled to room temperature.

(4) Preparing a hole transport layer Spiro-OMeTAD by adopting a single-step static spin coating method, namely setting a spin coater to rotate for 30s, placing the prepared semi-finished product, uniformly coating 70u L of the prepared Spiro-OMeTAD solution on a sample, starting the spin coater, and preparing the sample for evaporating an electrode after the spin coating.

(5) And (3) evaporating a gold electrode by adopting a thermal evaporation method, putting the substrate which is spin-coated with the HTM into a designed metal mould, and evaporating metal Au on the surface layer (with the thickness of about 60nm) of the HTM in a vacuum coating instrument to obtain the perovskite light-emitting diode (Pe-L ED) with a complete structure.

For Au/Spiro-OMeTAD/Cs grown under the above conditions_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃/SnO₂The J-V performance test is carried out on the/ITO/PEN. The test result shows that Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The base light emitting diode has good diode rectification characteristics (see fig. 2).

Example 3:

(1) Before preparing the electron transport layer, 2.5 × 2.5.5 cm was first taped²The flexible and bendable PEN/ITO substrate with a layer of ITO grown on the surface is selectively covered, zinc powder and 2M dilute hydrochloric acid are used for etching, and then cotton is used for wiping off residual zinc powder. Ultrasonic cleaning with detergent, ultrapure water, acetone, and ethanol for 30 min. And (4) after the washed glass is dried, treating for 60min by using ultraviolet-ozone cleaning equipment, and storing in a dust-free environment for later use.

(2) Preparation of amorphous non-continuous SnO by adopting single-step spin coating process₂An electron transport layer. Starting the spin coater, setting 3000 turns for 30s, placing the PEN flexible substrate, adsorbing and starting the spin coater to enable SnO to be coated₂Diluting sol gel with 10 times of anhydrous ethanol, and taking 70u L prepared SnO₂And (3) dropping the diluted sol-gel on a rotating substrate stably at a constant speed within 20-22 s from the end of rotation, stopping the rotation of a spin coater, moving the sample to a hot plate at 100 ℃, annealing for 1h, and then placing the sample into ozone for treatment for 20-30 min.

(3)Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The mixed perovskite layer is prepared by adopting a single-step dropwise adding anti-solvent method for spin coating, namely, the solution precursor is uniformly coated on a sample treated by ozone, a spin coating machine is started, the spin coating setting conditions are that firstly 1000 turns to 10s, then 5000 turns to 30s, 120u L trifluorotoluene solution is taken,the solution is quickly dropped onto the spinning sample between 14 and 16 seconds from the end of the spin-coater rotation. And after the spin coater stops rotating, moving the sample to a hot plate at 85 ℃, annealing for 40min, and then moving the sample to a vessel to naturally cool to room temperature.

(5) Placing the substrate with HTM in a designed metal mold, and evaporating Au on the surface layer (thickness about 60nm) of HTM in a vacuum coating apparatus to obtain perovskite light-emitting diode (Pe-L ED) with complete structure

For Au/Spiro-OMeTAD/Cs grown under the above conditions_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃/SnO₂The test results show that the photoluminescence (P L) spectrum before and after bending (see FIG. 3) and the P L spectrum after bending for different times (see FIG. 4) are almost negligible, and meanwhile, the electroluminescence spectrum after 2000 times of bending is basically consistent with that when not bent (see FIG. 5).

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible red light electric injection luminescent device based on a metal halide perovskite luminescent layer is characterized by comprising an anode layer, a hole transport layer, a perovskite luminescent layer and an electron transport layer which are sequentially arrangedAnd a flexible substrate; the anode layer adopts Au, the hole transport layer adopts Spiro-OMeTAD, and the perovskite luminescent layer adopts Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃The electron transmission layer is made of amorphous discontinuous electron transmission material SnO₂The flexible substrate adopts ITO/PEN;

the preparation method of the flexible red light electro-injection light-emitting device based on the metal halide perovskite light-emitting layer comprises the following steps: on a flexible conductive ITO/PEN substrate, adopting a full low-temperature solution method to sequentially grow an electron transport layer, a perovskite luminescent layer and a hole transport layer, and evaporating a gold electrode on the hole transport layer to prepare a flexible red light electro-injection luminescent device based on the metal halide perovskite luminescent layer;

the preparation method of the hole transport layer Spiro-OMeTAD solution comprises the following steps of adding a hole transport material Spiro-OMeTAD into a mixed solution of a lithium bis (trifluoromethanesulfonylimide) solution, 4-tert-butylpyridine, a Co salt solution and chlorobenzene, and uniformly stirring to prepare the Spiro-OMeTAD solution, wherein the volume ratio of L i-TFSI solution, TBP, the Co salt solution and the chlorobenzene in the mixed solution is 0.018-0.019: 0.029-0.031: 0.017-0.019: 0.92-0.94.

2. The flexible red-light electro-injection light emitting device based on a metal halide perovskite light emitting layer of claim 1, wherein the amorphous discontinuous electron transport material is SnO₂The preparation method comprises the following steps: SnCl_2·2H₂Dissolving O in absolute ethyl alcohol to obtain SnCl_2·2H₂Refluxing an absolute ethyl alcohol solution with the O concentration of 0.10-0.12 g/1m L at 70-80 ℃ for 2.5-3.5 h, aging at 20-40 ℃ for 2.5-3.5 h, and placing at room temperature for 1-3 d to obtain light yellow sol, namely the amorphous non-continuous electron transmission material SnO₂。

3. The flexible red-light electro-injection light emitting device based on a metal halide perovskite light emitting layer as claimed in claim 1, wherein the mixed perovskite precursor solution is prepared by the following method:

step 1, firstly, mixing a mixture of a mass ratio of 0.645-0.655: 0.102 to 0.104: 0.218 to 0.225:

0.024-0.032 PbI₂、PbBr₂、HC(NH₂)₂I (FAI) and CH₃NH₃Br (MABr), dissolving the mixture in a mixed solvent of DMF and DMSO with the volume ratio of 0.7-0.9: 0.1-0.3, and stirring at the temperature of 55-65 ℃ for 0.5-1.5 h to obtain a precursor I; the mass ratio of the mixture to the mixed solvent is 760-800: 0.9 to 1.1;

step 2, dissolving the CsI in DMSO to obtain a DMSO solution with the CsI concentration of 0.38-0.4 mg/1u L, and stirring for 0.5-1.5 h at the temperature of 55-65 ℃ to obtain a precursor II;

and 3, mixing the first precursor and the second precursor according to the volume ratio of 0.03-0.07: 0.93-0.97 to prepare the mixed perovskite precursor solution.

4. The method of making a flexible red-light electron injection light emitting device based on a metal halide perovskite light emitting layer as claimed in claim 1 wherein growing an electron transport layer on a flexible conductive ITO/PEN substrate comprises the steps of: preparing the electron transmission layer by adopting a single-step spin coating method, starting a spin coater, setting 3000 revolutions for 30s, placing an ITO/PEN flexible substrate on a rotary bracket of the spin coater, fixing the ITO/PEN flexible substrate by vacuum adsorption, starting the spin coater, and taking the prepared amorphous discontinuous electron transmission material SnO₂Dropping the sample on a rotating ITO/PEN flexible substrate at a stable and uniform speed within 20-22 s from the end of rotation, moving the sample to a hot plate at 100 ℃ after a spin coater stops rotating, annealing for 0.5-1.5 h, and then placing the sample into ozone for treatment for 20-30 min;

the perovskite luminescent layer is prepared by a single-step dropwise adding anti-solvent method through spin coating; uniformly coating the mixed perovskite precursor liquid on a sample subjected to ozone treatment, and starting a spin coating machine, wherein the spin coating setting is that firstly 1000 turns to 10s, and then 5000 turns to 30 s; taking a trifluorotoluene solution, and quickly dropwise adding the trifluorotoluene solution onto a rotating sample within 14-16 s from the rotation end of a spin coater; after the spin coater stops rotating, moving the sample to a hot plate at 85 ℃, and annealing for 30-50 min; then moving the sample into a vessel and naturally cooling to room temperature;

spin coating a hole transport layer and evaporating a gold electrode to obtain a structure of Au/Spiro-OMeTAD/Cs_0.05FA_0.8075MA_0.1425Pb(I_0.85Br_0.15)₃/SnO₂Flexible red light electron injection light emitting device based on metal halide perovskite light emitting layer of/ITO/PEN.