CN114784215A

CN114784215A - Preparation method of quasi-two-dimensional blue light LED device

Info

Publication number: CN114784215A
Application number: CN202210336424.XA
Authority: CN
Inventors: 白雪; 张富俊; 张宇; 武振南; 陆敏; 郜艳波
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2022-07-22

Abstract

The invention is suitable for the field of light emitting diodes, and provides a preparation method of a quasi-two-dimensional blue light LED device. In the preparation process of the device, the metal nanoclusters are mixed with the traditional transmission layer, and the electrical property of the original transmission layer is adjusted, so that the effect of balancing carrier transmission is realized, the performance of the perovskite light-emitting device is improved finally, the preparation method has the advantages of simple preparation process and high efficiency, and the problem of low efficiency of the existing blue light quasi-two-dimensional LED device is solved.

Description

Preparation method of quasi-two-dimensional blue light LED device

Technical Field

The invention belongs to the field of light emitting diodes, and particularly relates to a preparation method of a quasi-two-dimensional blue light LED device.

Background

The quasi-two-dimensional metal halide perovskite material has wide prospect in the fields of light-emitting diodes and display application due to high photoluminescence quantum yield, adjustable optical band gap, excellent color purity and low-cost solution processability.

However, the current light emitting diode using perovskite material as the light emitting layer still has much lower photoelectric properties than the organic light emitting diode. On one hand, the crystallization process of the perovskite film solution is difficult to control, so that the film has poor crystallization quality, uneven phase distribution and over-low energy transmission efficiency, and excessive non-radiative recombination defects are generated; on the other hand, the carrier injection is difficult due to the absence of a transmission layer with proper energy level, so that the carrier transmission in the device is unbalanced, the efficiency of the device is low, and the industrial application of the perovskite thin film and the equipment thereof is severely restricted. For a quasi-two-dimensional blue light LED device, due to the fact that a blue light emitting band gap is large, the HOMO energy level of the quasi-two-dimensional blue light LED device is deep, and the fact that no hole transmission material with appropriate mobility and energy level exists is one of main reasons for further improving the efficiency of the quasi-two-dimensional blue light LED device.

Disclosure of Invention

The embodiment of the invention aims to provide a preparation method of a quasi-two-dimensional blue light LED device, and aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of a quasi-two-dimensional blue light LED device comprises the following steps:

step 1: repeatedly cleaning the ITO substrate by using deionized water, ethanol and acetone respectively, and then cleaning for 20 minutes by using an ultraviolet ozone machine;

step 2: depositing a PEDOT (PSS) solution on the surface of the substrate in the step 1 in a spin coating manner, performing post annealing at 150 ℃, dissolving a mixed material of a conductive polymer, a metal nanocluster and the conductive polymer in an organic reagent, depositing the mixed material on the surface of the substrate by a spin coating method, and performing post annealing at 150 ℃;

and 3, step 3: dissolving a proper amount of lead iodide, phenylbutylammonium bromide and cesium bromide into 1 ml of DMSO solution to form a perovskite precursor solution;

and 4, step 4: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 3 to the surface of the substrate obtained in the step 2, preparing a thin film in a spin coating mode, dropwise adding 150 microliters of an anti-solvent to the surface of the perovskite thin film within a certain time, wherein the anti-solvent is one of ethyl acetate, chlorobenzene and toluene, so that the thin film is rapidly crystallized, and then placing the thin film on a heating table for later-stage annealing crystallization;

and 5: and (4) putting the film obtained in the step (4) into an evaporation instrument, and evaporating an electron transmission layer and a metal aluminum electrode.

Further, in the step 2, the conductive polymer is one of PVK, Poly-TPD, PTAA, and TFB.

Further, in the step 2, in the mixed material of the metal nanoclusters and the conductive polymer, the metal nanoclusters are one of oil-soluble gold nanoclusters, oil-soluble silver nanoclusters, and oil-soluble copper nanoclusters.

Further, in the step 2, in the mixed material of the metal nanoclusters and the conductive polymer, the metal nanoclusters account for 5% to 55% of the mixed material.

Further, the metal nanoclusters serve to enhance hole conductivity.

Further, in the step 2, the organic reagent is one of DMSO, DMF, CB, and m-xylene.

Further, in the step 5, the electron transport material is one of TPBi/LiF, TPBi/Liq, Tmpypb/LiF and Tmpypb/Liq.

Compared with the prior art, the invention has the beneficial effects that:

according to the preparation method of the quasi-two-dimensional blue light LED device, the oil-soluble metal nanoclusters are doped into the organic conducting polymer, so that the injection and transmission of hole carriers of the quasi-two-dimensional blue light LED device are effectively improved; by utilizing the molecular state characteristics of the metal nanoclusters, metal can be doped into the transmission layer in another mode, the conductivity and the carrier mobility of the conductive polymer are improved by utilizing the metallicity of the metal nanoclusters, and meanwhile, the energy level difference between the HOMO energy level of the hole transmission layer and the HOMO energy level of the quasi-two-dimensional blue-light perovskite light emitting layer is smaller by utilizing pi-pi stacking between ligands of the metal nanoclusters and benzene rings in the conductive polymer, so that the injection efficiency of holes is improved.

Drawings

FIG. 1 is a graph comparing film roughness before and after experimental optimization of an embodiment of the present invention.

FIG. 2 is a graph comparing the conductivity of the films before and after experimental optimization in the examples of the present invention.

FIG. 3 is a graph showing the comparison of the carrier mobility of thin films before and after experimental optimization in the example of the present invention.

Fig. 4 is a comparison graph of current density and turn-on voltage of the device before and after experimental optimization in the embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

Specific implementations of the present invention are described in detail below with reference to specific embodiments.

Example 1

One embodiment of the invention provides a preparation method of a quasi-two-dimensional blue light LED device, which comprises the following steps:

step 1: repeatedly cleaning the ITO substrate with deionized water, ethanol and acetone respectively, and then cleaning for 20 minutes by adopting an ultraviolet ozone machine;

and 2, step: PSS solution is deposited on the surface of the substrate in the step 1 in a spin coating mode, and post annealing is carried out at 150 ℃;

and 3, step 3: dissolving a proper amount of TFB in CB, depositing the solution on the surface of the substrate in the step 2 in a nitrogen glove box by using a spin coating mode, and performing post annealing at 150 ℃;

and 4, step 4: dissolving a proper amount of PVK and oil-soluble silver nanoclusters in CB, depositing the solution on the surface of the substrate in the step 3 in a nitrogen glove box in a spin coating mode, and performing post annealing at 150 ℃;

and 5: dissolving a proper amount of lead iodide, phenylbutylammonium bromide and cesium bromide into 1 ml of DMSO solution to form a perovskite precursor solution;

and 6: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 5 to the surface of the substrate obtained in the step 4, preparing a film in a spin coating mode, dropwise adding 150 microliters of ethyl acetate serving as an anti-solvent to the surface of the perovskite film at a certain time so as to rapidly crystallize the film, and then putting the film on a heating table for later-stage annealing crystallization;

and 7: and (4) putting the film obtained in the step (6) into an evaporation instrument, and evaporating an electron transport layer TPBi/Liq and a metal aluminum electrode.

In the embodiment of the invention, the perovskite film is composed of a quasi-two-dimensional perovskite film, and the quasi-two-dimensional film is constructed by adding a long-chain organic group into a three-dimensional perovskite so as to enhance the quantum confinement effect and obtain the blue shift of the luminescent peak position of the device; preferably, the doping of the metal nanoclusters cannot increase the roughness of the transmission layer film after optimization by more than 50% compared with the roughness before optimization, and the roughness of the perovskite layer film prepared by the spin coating method cannot increase by more than 50% compared with the roughness before optimization; the doping of the metal nanoclusters improves hole conductivity, improves energy levels so that the energy levels of the hole transport layer and the light emitting layer are more matched, and thus improves hole injection efficiency, which is reflected in a reduction in turn-on voltage (voltage with luminance of 1 candela per square meter). Referring to fig. 1 to 4, the silver nanoclusters are doped into the conductive polymer PVK as a dopant to serve as a hole transport layer, so that the hole mobility of the PVK is improved, the energy level of the PVK is improved, the carrier injection with matched energy levels is realized, and the carrier injection efficiency is improved. The transition size of the metal nanocluster has both metallic and molecular characteristics, so that the limitation of independent action of inorganic silver salt and organic ligand can be overcome, and the method is a very good way for improving the transmission material. By doping with a suitable concentration, the metal nanoparticles do not greatly improve the film forming characteristics of the transmission layer and do not affect the film forming characteristics of the perovskite. The doping of the silver nanoclusters can obviously enhance the transmission and injection of hole carriers, so that balanced carrier transmission is constructed, and the performance of a high-brightness high-efficiency blue light LED device is realized.

Example 2

step 2: depositing a PEDOT (PSS) solution on the surface of the substrate in the step 1 in a spin coating mode, and performing post annealing at 150 ℃;

and step 3: dissolving a proper amount of Poly-TPD in m-xylene, depositing the solution on the surface of the substrate in the step 2 in a nitrogen glove box in a rotary coating mode, and performing post-annealing at 150 ℃;

and 4, step 4: dissolving a proper amount of PTAA and oil-soluble copper nanoclusters in CB, depositing the solution on the surface of the substrate in the step 3 in a nitrogen glove box in a spin coating mode, and performing post annealing at 150 ℃;

and 6: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 5 to the surface of the substrate obtained in the step 4, preparing a thin film in a spin coating mode, dropwise adding 150 microliters of chlorobenzene serving as an anti-solvent to the surface of the perovskite thin film at a certain time so as to quickly crystallize the thin film, and then putting the thin film on a heating table for later-stage annealing crystallization;

and 7: and (4) putting the film obtained in the step (6) into an evaporation instrument, and evaporating an electron transport layer TPBi/LiF and a metal aluminum electrode.

Example 3

The preparation method of the quasi-two-dimensional blue light LED device provided by one embodiment of the invention comprises the following steps:

step 2: PSS solution is deposited on the surface of the substrate in the step 1 in a spin coating mode, and post annealing is carried out at 150 ℃;

and 3, step 3: dissolving a proper amount of TFB in DMSO, depositing the TFB on the surface of the substrate in the step 2 in a nitrogen glove box in a spin coating mode, and performing post annealing at 150 ℃;

and 4, step 4: dissolving a proper amount of Poly-TPD and oil-soluble copper nanoclusters in CB, depositing the solution on the surface of the substrate in the step 3 in a nitrogen glove box by using a spin coating mode, and performing post annealing at 150 ℃;

step 6: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 5 to the surface of the substrate obtained in the step 4, preparing a film in a spin coating mode, dropwise adding 150 microliters of ethyl acetate serving as an anti-solvent to the surface of the perovskite film at a certain time so as to rapidly crystallize the film, and then putting the film on a heating table for later-stage annealing crystallization;

Example 4

and step 3: dissolving a proper amount of TFB in DMSO, depositing on the surface of the substrate in the step 2 in a nitrogen glove box in a spin coating mode, and performing post annealing at 150 ℃;

and 7: and (3) putting the film obtained in the step (6) into an evaporation instrument, and evaporating an electron transport layer Tmpypb/Liq and a metal aluminum electrode.

Example 5

and 3, step 3: dissolving a proper amount of Poly-TPD in CB, depositing the solution on the surface of the substrate in the step 2 in a nitrogen glove box in a spin coating mode, and performing post-annealing at 150 ℃;

step 6: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 5 to the surface of the substrate obtained in the step 4, preparing a film in a spin coating mode, dropwise adding 150 microliters of ethyl acetate serving as an anti-solvent to the surface of the perovskite film at a certain time so as to quickly crystallize the film, and then putting the film on a heating table for later-stage annealing crystallization;

and 7: and (4) putting the film obtained in the step (6) into an evaporation instrument, and evaporating an electron transmission layer Tmpypb/Liq and a metal aluminum electrode.

Example 6

and 3, step 3: dissolving a proper amount of PTAA and oil-soluble silver nanoclusters in CB, depositing the solution on the surface of the substrate in the step 2 in a nitrogen glove box in a spin coating mode, and performing post annealing at 150 ℃;

and 4, step 4: dissolving a proper amount of lead iodide, phenylbutylammonium bromide and cesium bromide into 1 ml of DMSO solution to form a perovskite precursor solution;

and 5: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 4 to the surface of the substrate obtained in the step 3, preparing a film in a spin coating mode, dropwise adding 150 microliters of ethyl acetate serving as an anti-solvent to the surface of the perovskite film at a certain time so as to quickly crystallize the film, and then putting the film on a heating table for later-stage annealing crystallization;

and 6: and (4) putting the film obtained in the step (5) into an evaporation instrument, and evaporating an electron transmission layer Tmpypb/Liq and a metal aluminum electrode.

Example 7

and step 3: dissolving a proper amount of PVK and oil-soluble copper nanoclusters in DMF (dimethyl formamide), depositing the solution on the surface of the substrate in the step 2 in a nitrogen glove box in a spin coating mode, and performing post annealing at 150 ℃;

and 5: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 4 to the surface of the substrate obtained in the step 3, preparing a film in a spin coating mode, dropwise adding 150 microliters of ethyl acetate serving as an anti-solvent to the surface of the perovskite film at a certain time so as to rapidly crystallize the film, and then putting the film on a heating table for later-stage annealing crystallization;

and 6: and (3) putting the film obtained in the step (5) into an evaporation instrument, and evaporating an electron transport layer Tmpypb/Liq and a metal aluminum electrode.

The working principle of the invention is as follows:

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, it is possible to make several variations and modifications without departing from the concept of the present invention, and these should be considered as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicability of the patent.

Claims

1. A preparation method of a quasi-two-dimensional blue light LED device is characterized by comprising the following steps:

step 2: PSS solution is deposited on the surface of the substrate in the step 1 in a spin coating mode, post annealing is carried out at 150 ℃, mixed materials of conductive polymers, metal nanoclusters and conductive polymers are dissolved in organic reagents and then deposited on the surface of the substrate through a spin coating method, and post annealing is carried out at 150 ℃;

and 4, step 4: dropwise adding a proper amount of the perovskite precursor solution obtained in the step 3 onto the surface of the substrate obtained in the step 2, preparing a film in a spin coating mode, dropwise adding 150 microliters of an anti-solvent onto the surface of the perovskite film within a certain time, wherein the anti-solvent is one of ethyl acetate, chlorobenzene and toluene, so that the film is rapidly crystallized, and then putting the film on a heating table for later annealing crystallization;

2. The method for manufacturing a quasi-two-dimensional blue LED device according to claim 1, wherein in the step 2, the conductive polymer is one of PVK, Poly-TPD, PTAA and TFB.

3. The method for manufacturing a quasi-two-dimensional blue LED device according to claim 2, wherein in the step 2, the metal nanoclusters are one of oil-soluble gold nanoclusters, oil-soluble silver nanoclusters, and oil-soluble copper nanoclusters in the mixed material of the metal nanoclusters and the conductive polymer.

4. The method for manufacturing a quasi-two-dimensional blue light LED device according to claim 3, wherein in the step 2, the metal nanoclusters in the mixed material of the metal nanoclusters and the conductive polymer account for 5% -55% of the mixed material.

5. The method of claim 4, wherein the metal nanoclusters are used to enhance hole conductivity.

6. The method of claim 4, wherein in the step 2, the organic reagent is one of DMSO, DMF, CB and m-xylene.

7. The method of claim 1, wherein in step 5, the electron transport material is one of TPBi/LiF, TPBi/Liq, Tmpypb/LiF, and Tmpypb/Liq.