CN113848600A - Microlens array template and preparation method thereof, scattering type microlens, substrate and preparation method and application thereof, and quantum dot light-emitting diode - Google Patents

Microlens array template and preparation method thereof, scattering type microlens, substrate and preparation method and application thereof, and quantum dot light-emitting diode Download PDF

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CN113848600A
CN113848600A CN202111106317.XA CN202111106317A CN113848600A CN 113848600 A CN113848600 A CN 113848600A CN 202111106317 A CN202111106317 A CN 202111106317A CN 113848600 A CN113848600 A CN 113848600A
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scattering
template
substrate
concave
microlens
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CN113848600B (en
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杜祖亮
王书杰
徐博
方岩
王啊强
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Henan University
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Henan University
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0012—Arrays characterised by the manufacturing method
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0012—Arrays characterised by the manufacturing method
    • G02B3/0018—Reflow, i.e. characterized by the step of melting microstructures to form curved surfaces, e.g. manufacturing of moulds and surfaces for transfer etching
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0012—Arrays characterised by the manufacturing method
    • G02B3/0031—Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/0056—Arrays characterized by the distribution or form of lenses arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/85—Arrangements for extracting light from the devices
    • H10K50/858—Arrangements for extracting light from the devices comprising refractive means, e.g. lenses

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Abstract

The invention belongs to the technical field of display illumination, and particularly relates to a micro-lens array template and a preparation method thereof, a scattering micro-lens, a substrate and a preparation method and application thereof, and a quantum dot light-emitting diode. The concave micro-lens array template provided by the invention is characterized in that the concave transparent array template is a polystyrene concave micro-lens array template, a polydimethylsiloxane concave micro-lens array template or an impact-resistant polystyrene concave micro-lens array template, the surface of the concave micro-lens array template is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently. The scattering type microlens obtained by the concave microlens array template provided by the invention can effectively improve the output efficiency of the QLED when being used singly, and the QLED has a simple structure.

Description

Microlens array template and preparation method thereof, scattering type microlens, substrate and preparation method and application thereof, and quantum dot light-emitting diode
Technical Field
The invention belongs to the technical field of display illumination, and particularly relates to a micro-lens array template and a preparation method thereof, a scattering micro-lens, a substrate and a preparation method and application thereof, and a quantum dot light-emitting diode.
Background
Because the quantum dots have unique optical properties of continuously adjustable light-emitting wavelength along with size and components, narrow light-emitting spectrum, high fluorescence efficiency, good stability and the like, the quantum-dot-based electroluminescent diode (QLED) is widely concerned and researched. In addition, the QLED display has advantages that cannot be realized by many Liquid Crystal Displays (LCDs), such as a large viewing angle, a high contrast ratio, a fast response speed, and flexibility, and is thus expected to become a next-generation display technology.
Currently, QLEDs generally employ a sandwich-type multilayer stack structure including a substrate, an anode layer, a hole injection layer, a hole transport layer, a quantum dot light emitting layer, an electron transport layer, and a cathode layer. Although the quantum yield of the quantum dot light emitting layer exceeds 90%, the light emitting efficiency of the current QLED device is low due to light emitting losses of three modes, namely plasma mode (plasmon mode), waveguide mode (waveguiding mode) and substrate mode (substretting mode), and only 20% of light can be transmitted.
In order to reduce the above loss, the light extraction structure is generally designed to increase the light extraction rate in the prior art. The light extraction structure of the conventional QLED lighting device is classified into a microlens structure, a diffusion structure, and a diffraction structure according to functions, and is classified into an inner structure and an outer structure according to positions.
Chinese patent CN105531824 discloses a light extraction structure of an Organic Light Emitting Diode (OLED) display, which includes an encapsulation layer or a substrate layer, an array of lenses and an array of light emitting pixels, wherein the light extraction efficiency of the OLED is improved by the array of lenses and the array of light emitting pixels, and the structure is complex.
Disclosure of Invention
In view of the above, the invention provides a microlens array template and a preparation method thereof, a scattering microlens, a substrate and a preparation method and application thereof, and a quantum dot light-emitting diode.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a concave micro-lens array template, wherein the concave transparent array template is a polystyrene concave micro-lens array template, a polydimethylsiloxane concave micro-lens array template or an impact-resistant polystyrene concave micro-lens array template, the surface of the concave micro-lens array template is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently.
The invention provides a preparation method of the concave micro-lens array template in the technical scheme, which comprises the following steps:
standing a polystyrene substrate coated with trichloromethane in a water vapor atmosphere to obtain a polystyrene concave micro-lens array template, wherein the humidity of the water vapor atmosphere is more than or equal to 60%, the temperature of the water vapor atmosphere is 25-30 ℃, and the surface of the polystyrene substrate coated with trichloromethane is horizontally placed upwards;
the preparation method of the polydimethylsiloxane concave micro-lens array template comprises the following steps:
pouring the polydimethylsiloxane casting solution into the polystyrene concave micro-lens array template, and performing thermal curing and demolding in sequence to obtain the polydimethylsiloxane concave micro-lens array template;
the preparation method of the impact-resistant polystyrene concave micro-lens array template comprises the following steps:
and imprinting the polydimethylsiloxane concave micro-lens array template with an impact-resistant polystyrene film to obtain the impact-resistant polystyrene micro-lens array template.
The invention provides a scattering type micro lens which is provided with a scattering type micro lens array surface, wherein the chemical composition of the scattering type micro lens comprises nanometer scattering particles and a curing agent, the scattering type micro lens array surface is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently.
Preferably, the nanometer isThe scattering particles comprise SiO2、TiO2And Al2O3One or more of; the particle size of the nano scattering particles is 200-800 nm.
Preferably, the mass percentage of the nano scattering particles in the scattering type microlens is 5-20%.
Preferably, the thickness of the scattering type microlens is less than or equal to 10 μm.
The invention provides a substrate, which comprises a base and a scattering type micro lens arranged on the back surface of the base, wherein the scattering type micro lens is the scattering type micro lens in the technical scheme.
The invention provides a preparation method of the substrate in the technical scheme, which comprises the following steps:
coating scattering liquid on the back surface of the substrate to obtain a scattering coating, wherein the scattering liquid comprises nanometer scattering particles, a curing agent and a polar organic solvent;
and (3) adopting a template to imprint the scattering coating, then curing, and demolding to obtain the substrate, wherein the template is the concave micro-lens array template in the technical scheme.
The invention provides an application of the substrate in the technical scheme or the substrate prepared by the preparation method in the technical scheme in a light-emitting diode lighting device.
The invention provides a quantum dot light-emitting diode which comprises a substrate, and an anode layer, a hole injection layer, a hole transmission layer, a quantum dot light-emitting layer, an electron transmission layer and a cathode layer which are sequentially arranged on the surface of the substrate, wherein the back of the substrate is provided with a scattering type micro lens according to the technical scheme.
The invention provides a concave micro-lens array template, wherein the concave transparent array template is a polystyrene concave micro-lens array template, a polydimethylsiloxane concave micro-lens array template or an impact-resistant polystyrene concave micro-lens array template, the surface of the concave micro-lens array template is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently. The concave micro-lens array template provided by the invention has a periodic quasi-hemispherical array structure, the diameter of the quasi-hemispherical array structure is independent and is more than or equal to 5 micrometers, the height of the peak of the quasi-hemispherical array structure is independent and is more than or equal to 2 micrometers, scattering micro-lenses obtained by the concave micro-lens array template provided by the invention form a periodic interface of a quasi-hemispherical convex structure, the diameter of the quasi-hemispherical convex structure is independent and is more than or equal to 5 micrometers, and the peak is independent and is more than or equal to 2 micrometers.
The preparation method of the concave micro-lens array template provided by the invention has the advantages of large-area preparation, simple construction mode and low cost, and is beneficial to industrial popularization and application.
The invention provides a scattering type micro lens which is provided with a scattering type micro lens array surface, wherein the chemical composition of the scattering type micro lens comprises nanometer scattering particles and a curing agent, the scattering type micro lens array layer is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently. The scattering type microlens provided by the invention has a scattering type microlens array surface, and the chemical composition comprises nanometer scattering particles and a curing agent, wherein the nanometer scattering particles can converge light rays incident on nano particles to particles in the front, so that the forward scattering is enhanced, the light emitting efficiency is improved, and meanwhile, the emergent light angle dependence characteristic brought by the microlens array is improved, so that the emergent light rays are distributed more uniformly. Therefore, when the scattering type micro lens obtained by the concave micro lens array template provided by the invention is used independently, the high efficiency of the QLED can be effectively improved, and the QLED has a simple structure.
The invention provides a quantum dot light-emitting diode which comprises a substrate, and an anode layer, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode layer which are sequentially arranged on the surface of the substrate, wherein the back of the substrate is provided with a scattering type micro lens. The quantum dot light-emitting diode provided by the invention comprises the scattering type micro lens arranged on the back surface of the substrate, the incident angle of an air interface can be reduced through the micro lens array structure, so that light rays with large angles are emitted, the internal total reflection and internal heat accumulation at the substrate interface of the quantum dot light-emitting diode device are reduced, the nano scattering particles in the micro lens array layer can enhance the forward scattering, meanwhile, the emitted light rays are distributed more uniformly and are closer to lambertian emission, and the angle dependence of the device is reduced. The embodiment result shows that, compared with a standard quantum dot light emitting diode (standard device), the quantum dot light emitting diode with the scattering type microlens array layer provided by the invention does not change the electrical property of the device, and under the condition that the current density is not changed, compared with the standard device, the light emitting efficiency of the device is increased, so that the maximum external quantum efficiency of the green light QLED device with the microlens array layer of the nanometer scattering particles reaches 25.11%, and is improved by 21% compared with the standard device with the maximum external quantum efficiency of 20.74%, and the structure is simple.
Drawings
FIG. 1 is a flow chart of a fabrication process for providing a concave microlens array template according to example 1 of the present invention;
FIG. 2 is an electron micrograph of a concave microlens array template prepared in examples 1 to 4 of the present invention
FIG. 3 is a schematic diagram of a standard QLED device fabricated according to comparative example 10 of the present invention;
FIG. 4 is a flowchart of a process for manufacturing a scattering type microlens provided in example 5 of the present invention;
FIG. 5 is an electron micrograph of a scattering layer prepared in examples 5 to 8 of the present invention;
FIG. 6 is an electron micrograph of a scattering type microlens prepared according to example 5 of the present invention;
FIG. 7 is an electron micrograph of a concave microlens array template prepared according to comparative examples 1 to 4;
FIG. 8 shows three device structures (standard device, MLAs device and with SiO) prepared in the implementation and comparative examples2MLAs devices with nano-scattering particles) power efficiency as a function of current density;
FIG. 9 is a schematic view of an embodimentThree device structures (standard device, MLAs device and with SiO) prepared in comparative example2MLAs devices with nano-scattering particles) are obtained by the following steps of (1) a graph of the current density and the external quantum efficiency of three device structures of a MLAs device with nano-scattering particles along with the change of voltage;
fig. 10 shows EL lines of the devices measured at different angles for three device structures prepared by the example and the comparative example.
FIG. 11 is a graph of lateral light distribution of a device substrate modeled using Lighttools Monte Carlo ray tracing for three device structures fabricated in accordance with the examples and comparative examples;
figure 12 illustrates the use of Lighttools to simulate tracking 500000 light rays exiting the interior of the device for three device structures prepared for implementation and comparative example.
Detailed Description
The invention provides a concave micro-lens array template, wherein the concave transparent array template is a polystyrene concave micro-lens array template, a polydimethylsiloxane concave micro-lens array template or an impact-resistant polystyrene concave micro-lens array template, the surface of the concave micro-lens array template is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently.
In the invention, the diameter of the quasi-hemispherical shape is preferably 5-8 μm.
In the invention, the height of the quasi-hemispherical peak is preferably 2-6 μm.
The invention provides a preparation method of the concave micro-lens array template in the technical scheme,
the preparation method of the polystyrene concave micro-lens array template comprises the following steps:
standing a Polystyrene (PS) substrate coated with trichloromethane in a water vapor atmosphere to obtain a PS concave micro-lens array template (PS template), wherein the humidity of the water vapor atmosphere is more than or equal to 60%, the temperature of the water vapor atmosphere is 25-30 ℃, and the surface of the polystyrene substrate coated with trichloromethane is horizontally placed upwards;
the preparation method of the polydimethylsiloxane concave micro-lens array template comprises the following steps:
pouring a Polydimethylsiloxane (PDMS) casting solution into the PS template, and performing thermal curing and demolding in sequence to obtain a PDMS concave micro-lens array template (PDMS flexible template);
the preparation method of the impact-resistant polystyrene concave micro-lens array template comprises the following steps:
and (3) stamping the impact-resistant polystyrene (IPS) film on the PDMS flexible template to obtain the micro-lens array template (IPS template) made of the impact-resistant polystyrene.
In the present invention, the starting materials are all commercially available products well known to those skilled in the art, unless otherwise specified.
In the invention, the preparation method of the polystyrene concave micro-lens array template comprises the following steps:
and standing the PS substrate coated with the trichloromethane on the surface in a water vapor atmosphere to obtain the PS template, wherein the humidity of the water vapor atmosphere is more than or equal to 60%, the temperature of the water vapor atmosphere is 25-30 ℃, and the surface of the polystyrene substrate coated with the trichloromethane is horizontally placed upwards.
In a specific embodiment of the present invention, the size of the PS substrate is preferably 2cm × 2cm × 1 mm.
In the invention, the trichloromethane is preferably drop-coated, and the invention has no special requirement on the specific implementation process of the drop coating. In a specific embodiment of the present invention, the chloroform is coated on one surface of the PS substrate.
In the present invention, the ratio of the coating volume of the chloroform to the area of the PS substrate is preferably 350. mu.L: 4cm2。
According to the invention, the surface of the PS substrate is coated with trichloromethane, and the trichloromethane can soften the surface of the PS substrate.
In the invention, the humidity of the water vapor atmosphere is not less than 60%, preferably 60-90%, in the specific embodiment of the invention, the humidity of the water vapor atmosphere is 60-65%, 70-75%, 80-85% or 90-95%.
In the invention, the temperature of the water vapor atmosphere is 25-30 ℃, and preferably 28 ℃.
In the invention, the standing time is preferably 0.5-2 h, and more preferably 1 h.
The surface of the PS substrate coated with the trichloromethane is horizontally placed upwards in a water vapor atmosphere, and micron-sized water drops obtained by condensing the water vapor extrude a hemispherical concave micro-lens array structure on the surface of the PS substrate coated with the trichloromethane under the action of gravity. And after the trichloromethane volatilizes, hardening the hemispherical concave micro-lens array structure to obtain the PS template.
After the PS template is obtained, the PDMS casting solution is poured into the PS template, and the PDMS flexible template is obtained after thermal curing and demolding in sequence.
In the invention, the PDMS casting solution preferably comprises PDMS and a thermal curing agent, the thermal curing agent is preferably SYLGARD184, and the mass ratio of the PDMS to the thermal curing agent is preferably (8-12): 1, and more preferably 10: 1.
In the present invention, the preparation method of the PDMS casting solution preferably includes the following steps: and mixing the PDMS and the thermal curing agent in sequence and standing in vacuum. In the invention, the mixing is preferably stirring mixing, and the mixing time is preferably 20-35 min. In the invention, the time of vacuum standing is preferably 1-3 h, and bubbles in the PDMS membrane casting solution are discharged through vacuum standing.
The invention has no special requirement on the pouring amount of the PDMS membrane casting solution, and can completely cover the surface of the PS template with the concave micro-lens array structure.
In the invention, the temperature for thermal curing is preferably 50-80 ℃, and more preferably 60 ℃. In the invention, the time for thermal curing is preferably 1-3 h, and more preferably 2 h.
After the thermal curing, the PDMS film and the PS template are peeled off, and the PDMS flexible template is obtained.
After the PDMS flexible template is obtained, the invention stamps (hereinafter referred to as first stamp) the impact-resistant IPS film on the PDMS flexible template to obtain the IPS template.
The source of the IPS film has no special requirement, and the IPS film can be obtained by adopting a commercial product.
In the present invention, the pressure of the first imprinting is preferably 15 to 25bar, and more preferably 20 bar. The temperature of the first imprinting is preferably 120-200 ℃, and more preferably 150 ℃. The time for the first imprinting is preferably 25 to 50s, and more preferably 30 s.
And demolding to obtain the IPS template after the first imprinting is finished, wherein in the invention, the demolding temperature is preferably 80-110 ℃, and more preferably 100 ℃.
In the invention, the PS template has high hardness, the PDMS flexible template has low strength, and the IPS template has proper hardness and strength and can be used for multiple times. In a specific embodiment of the present invention, the concave microlens array template is an IPS template.
The invention provides a scattering type micro lens which is provided with a scattering type micro lens array surface, wherein the chemical composition of the scattering type micro lens comprises nanometer scattering particles and a curing agent, the scattering type micro lens array surface is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 mu m independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 mu m independently.
The scattering type micro lens provided by the invention is provided with a scattering type micro lens array surface, in the invention, the scattering type micro lens array surface is a quasi-hemispherical array, the independent diameter of the quasi-hemispherical array is preferably 5-8 mu m, and the independent vertex height of the quasi-hemispherical array is preferably 2-6 mu m.
In the present invention, the scattering type microlens is preferably disposed on the back surface of the substrate. The invention has no special requirement on the material of the substrate. In an embodiment of the present invention, when the led device is a quantum dot led, the substrate is preferably made of glass.
In the present invention, the thickness of the scattering type microlens is preferably 10 μm or less, and more preferably 5 to 8 μm.
In the present invention, the chemical composition of the scattering type microlens includes nano scattering particles. In the present invention, the nano-scattering particles preferably include SiO2，TiO2And Al2O3More preferably one or more ofSiO2. In the present invention, the particle size of the nano scattering particles is preferably 200 to 800nm, and more preferably 250 to 600 nm. In a specific embodiment of the present invention, the nano scattering particles have a particle size of 200nm, 400nm, 600nm or 800 nm.
In the invention, the mass percentage of the nanometer scattering particles in the scattering type microlens is preferably 5-20%, and more preferably 10-15%. In a specific embodiment of the present invention, the mass percentage of the nano scattering particles in the scattering type microlens array layer is specifically 5%, 10%, 15% or 20%.
In the present invention, the chemical composition of the scattering type microlens includes a curing agent, and the refractive index of the curing agent is preferably similar to or the same as the refractive index of the substrate. In the present invention, the curing agent is preferably a uv curing agent. In a particular embodiment of the invention, when the substrate is glass, the curing agent is in particular NOA63 uv curing agent.
The invention provides a substrate, which comprises a base and a scattering type micro lens arranged on the back surface of the base, wherein the scattering type micro lens is the scattering type micro lens in the technical scheme.
The invention provides a preparation method of the substrate in the technical scheme, which comprises the following steps:
coating scattering liquid on the back surface of the substrate to obtain a scattering coating, wherein the scattering liquid comprises nanometer scattering particles, a curing agent and a polar organic solvent;
and (3) carrying out imprinting (hereinafter referred to as second imprinting) on the scattering coating by adopting a template, and then curing, and demoulding to obtain the substrate, wherein the template is the concave micro-lens array template in the technical scheme.
The back surface of the substrate is coated with scattering liquid to obtain a scattering coating, and the scattering liquid comprises nanometer scattering particles, a curing agent and a polar organic solvent.
In a particular embodiment of the invention, the substrate preferably has dimensions of 2cm × 2cm × 1 mm.
The invention preferably performs a pretreatment on the back surface of the substrate before the scattering liquid is coated, and in the invention, the pretreatment preferably comprises washing and ultraviolet ozone treatment in sequence. In the present invention, the washing solvent is preferably ethanol, and the present invention preferably wipes the back surface of the substrate with ethanol. In the invention, the ultraviolet ozone treatment is preferably carried out by treating the back surface of the substrate by adopting an ultraviolet ozone cleaning instrument, so as to improve the wettability of the back surface of the substrate, and in the invention, the treatment time is preferably 5-10 min.
In the present invention, the scattering liquid includes a polar organic solvent, and the polar organic solvent is preferably ethanol or acetone, and more preferably acetone.
In the present invention, the mass ratio of the curing agent to the polar organic solvent is preferably 1 (1-2), and more preferably 1: 1.
In the invention, the mass percentage of the nano scattering particles in the scattering liquid is preferably 2.5-15%, and more preferably 3-12%. In a specific embodiment of the present invention, the mass percentage of the nano scattering particles in the scattering liquid is specifically 2.5%, 5%, 7.5% or 10%. In the present invention, the nano scattering particles and the curing agent are the nano scattering particles and the curing agent described in the above technical scheme, and are not described herein again.
In the present invention, the method for preparing the scattering liquid preferably includes the steps of:
dispersing the nano scattering particles in the polar organic solvent to obtain nano scattering particle dispersion liquid;
and mixing the nano scattering particle dispersion liquid and the curing agent to obtain the scattering liquid.
The invention disperses the nanometer scattering particles in the polar organic solvent to obtain nanometer scattering particle dispersion liquid. In the invention, the dispersion is preferably ultrasonic dispersion, and the dispersion time is preferably 30-50 min.
After the nano scattering particle dispersion liquid is obtained, the nano scattering particle dispersion liquid and the curing agent are mixed to obtain the scattering liquid. In the invention, the mixing preferably comprises stirring mixing and ultrasonic mixing in sequence, wherein the stirring mixing time is preferably 30-50 min, and the ultrasonic mixing time is preferably 30-50 min. In the invention, the stirring mixing and the ultrasonic mixing are preferably circularly performed for 2-3 times as one mixing unit.
The preparation method of the scattering liquid provided by the invention can enable the nano scattering particles to be uniformly dispersed in the scattering liquid.
In the present invention, the ratio of the coating volume of the dispersion to the area of the back surface of the substrate is preferably 350. mu.L: 4cm2。
In the invention, the coating is preferably spin coating, in the invention, the rotation speed of the spin coating is preferably 1000-1500 rpm, and the volume ratio of the spin coating time to the scattering liquid is preferably 1s/30 muL.
In the invention, the thickness of the scattering coating is preferably less than or equal to 10 μm, and more preferably 5-8 μm.
After the scattering coating is obtained, the substrate is obtained after the scattering coating is subjected to second imprinting and solidification by adopting the template and demoulding.
In the invention, the template is the PS template, the PDMS flexible template or the IPS template in the technical scheme, and in a specific embodiment of the invention, the rage plate is the IPS template.
The invention has no special requirements for the specific implementation of the second embossing. In the specific embodiment of the invention, the microlens array template is manually imprinted on the scattering layer, clamped by a frame and placed in a vacuum environment, wherein the placing time is preferably 10-15 min, and bubbles between the mold and the scattering coating are discharged through vacuum placing.
After standing, the substrate with the mold is cured, in the invention, the curing is preferably photocuring, more preferably ultraviolet curing, the wavelength of the ultraviolet curing is preferably 365nm, and the curing time is preferably 15-20 min.
And demolding after curing to obtain the scattering type microlens.
The invention provides an application of the substrate in the technical scheme or the substrate prepared by the preparation method in the technical scheme in a light-emitting diode lighting device.
In the present invention, the light emitting diode lighting device is preferably a quantum dot light emitting diode lighting device.
The invention provides a quantum dot light-emitting diode which comprises a substrate, and an anode layer, a hole injection layer, a hole transmission layer, a quantum dot light-emitting layer, an electron transmission layer and a cathode layer which are sequentially arranged on the surface of the substrate, wherein the bottom surface of the substrate is provided with a scattering type micro lens.
The invention has no special requirements on the anode layer, the hole injection layer, the hole transport layer, the quantum dot luminescent layer, the electron transport layer and the cathode layer on the surface of the substrate.
In an embodiment of the present invention, the substrate is preferably made of glass.
In the invention, the anode layer is arranged on the surface of the substrate, the material of the anode layer is preferably ITO organic conductive glass, in the invention, a hole injection layer is arranged on the surface of the anode layer, and the exposed edge of the anode layer is used as the anode of the quantum dot light-emitting diode.
In the invention, a hole injection layer is arranged on the surface of the anode layer, and the material of the hole injection layer is preferably poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT: PSS).
In the invention, a hole transport layer is arranged on the surface of the hole injection layer, and the material of the hole transport layer is preferably poly (9, 9-dioctylfluorene-co-n- (4-butylphenyl) diphenylamine (TFB).
In the present invention, a quantum dot light emitting layer is disposed on the surface of the hole transport layer, and in a specific embodiment of the present invention, the quantum dot in the quantum dot light emitting layer is preferably CdSe @ ZnS with a core-shell structure.
In the invention, an electron transport layer is arranged on the surface of the quantum dot light emitting layer, and the material of the electron transport layer is preferably ZnO.
In the invention, a cathode layer is arranged on the surface of the electron transport layer, and the material of the cathode layer is preferably Al. In the present invention, the thickness of the cathode layer is preferably 100 nm.
In the invention, the scattering type micro lens is arranged on the back surface of the substrate, the scattering type micro lens is provided with a scattering type micro lens array surface, the chemical composition of the scattering type micro lens comprises nanometer scattering particles and a curing agent, the scattering type micro lens array surface is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 μm independently, and the height of the quasi-hemispherical apex is more than or equal to 2 μm independently.
In the invention, when the particle size of the nano scattering particles is preferably 200-800 nm, the wavelength range of emergent light emitted by the quantum dot (CdSe @ ZnS) luminescent layer with a core-shell structure is close to the particle size range of the nano scattering particles, and Mie scattering occurs on the nano scattering particles, wherein the Mie scattering has high forward scattering intensity and does not change the frequency of scattered light compared with Rayleigh scattering, Raman scattering or Brillouin scattering.
In the present invention, the method for preparing the quantum dot diode preferably includes the steps of:
and sequentially preparing an anode layer, a hole injection layer, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a cathode layer on the surface of the substrate to obtain the quantum dot light emitting diode standard device.
And preparing the scattering type micro lens on the back surface of the substrate of the quantum dot light-emitting diode standard device to obtain the quantum dot light-emitting diode.
And sequentially preparing an anode layer, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode layer on the surface of the substrate to obtain the quantum dot light-emitting diode standard device.
The anode layer is prepared on the surface of the substrate.
In the present invention, the substrate is preferably made of glass.
The substrate surface is preferably pre-treated in the present invention, preferably comprising washing, preferably scrubbed with ethanol in the present invention.
The anode layer is adhered to the surface of the substrate.
The hole injection layer is prepared on the surface of the anode layer, and the exposed edge of the anode layer is used as the anode of the quantum dot light-emitting diode.
After the anode layer is obtained, the surface of the anode layer is preferably subjected to pretreatment, and in the invention, the pretreatment preferably comprises washing with a detergent, washing with water, washing with an organic solvent, drying and ultraviolet ozone treatment in sequence. In the invention, the detergent cleaning preferably comprises room-temperature cleaning and high-temperature cleaning in sequence, the room-temperature cleaning preferably comprises the step of wiping the surface of the substrate by using a cleaning agent, the high-temperature cleaning preferably comprises ultrasonic cleaning, the high-temperature cleaning preferably comprises the step of 80 ℃, and the high-temperature cleaning preferably comprises the step of 20-30 min. In the present invention, the water washing is preferably ultra-pure water washing, the water washing is preferably performed under ultrasonic conditions, and the time of the water washing is preferably 15 min. In the present invention, the organic solvent washing preferably includes sequentially performing an acetone washing and an isopropanol washing, the acetone washing is preferably performed under ultrasonic conditions, the acetone washing time is preferably 15min, the isopropanol washing is preferably performed under ultrasonic conditions, and the isopropanol washing time is preferably 15 min. In the present invention, the drying is preferably blow-dried with nitrogen. In the present invention, the time of the ultraviolet ozone treatment is preferably 15min, and the ultraviolet ozone treatment is preferably performed in an ultraviolet ozone cleaning instrument.
In the invention, the preparation of the hole injection layer specifically comprises the following steps: and spin-coating a PEDOT PSS solution on the surface of the anode layer, and then thermally curing to obtain the hole injection layer.
According to the invention, the PEDOT/PSS solution is preferably subjected to pretreatment, in the invention, the pretreatment is preferably impurity removal, in the invention, the PEDOT/PSS solution is preferably filtered to remove large-particle solid impurities, and the filtering pore diameter of the filtering filter membrane is preferably 0.45 μm. The invention preferably adopts a disposable syringe to drip and coat the PEDOT: PSS solution on the surface of the anode layer.
After the PEDOT PSS solution is dripped, a spin coater is preferably adopted to carry out spin coating to obtain a wet PEDOT PSS film, wherein the spin speed is preferably 5000rpm, and the spin coating time is preferably 60 s.
After spin coating, the invention preferably adopts a cotton swab dipped with deionized water as the edge of the surface of the anode layer to obtain the anode.
After the anode is obtained, the PEDOT PSS wet film is subjected to thermal curing. In the present invention, the temperature of the thermal curing is preferably 150 ℃, the holding time of the thermal curing is preferably 15min, and in the specific implementation of the present invention, the thermal curing is preferably performed in an air environment.
After the thermal curing, the present invention preferably cools the thermally cured sample to obtain the hole injection layer, in the present invention, the cooling is preferably performed in a nitrogen atmosphere isolated from a water sample, and in the present embodiment, the cooling is performed in a glove box.
After obtaining the hole injection layer, the present invention preferably prepares the hole transport layer on the surface of the hole injection layer.
In the invention, the preparation of the hole transport layer specifically comprises the following steps: and (3) spin-coating the TFB solution on the surface of the hole injection layer, and then thermally curing to obtain the hole transport layer.
In the present invention, the TFB solution preferably has a mass concentration of 8 mg/mL. In the present invention, the solvent in the TFB solution is preferably chlorobenzene.
In the present invention, it is preferable that the TFB solution is subjected to a pretreatment, in the present invention, the pretreatment is preferably to remove impurities, in the present invention, the TFB solution is preferably to be filtered to remove large-particle solid impurities, and the filtration pore size of the filtration membrane is preferably 0.2 μm. The invention preferably employs a pipette to transfer the TFB solution to the surface of the anode layer.
In the present invention, the ratio of the mass of the TFB solution to the area of the surface of the hole injection layer is preferably 60 μ L/4cm2。
After the TFB solution is dripped, the TFB wet film is preferably obtained by spin coating with a homogenizer, wherein the spin coating speed is preferably 3000rpm, and the spin coating time is preferably 45 s.
After obtaining the TFB wet film, the invention thermally cures the TFB wet film. In the present invention, the temperature of the thermal curing is preferably 150 ℃, the holding time of the thermal curing is preferably 30min, and in the specific implementation of the present invention, the thermal curing is preferably carried out in a protective atmosphere, and the protective atmosphere is preferably nitrogen.
After the thermosetting, the present invention preferably cools the sample after the thermosetting to obtain the hole transport layer, and in the present invention, the cooling is preferably air cooling.
After obtaining the hole transport layer, the invention preferably prepares the quantum dot light emitting layer on the surface of the hole injection layer.
In the invention, the preparation of the quantum dot light-emitting layer specifically comprises the following steps: and spin-coating a quantum dot solution on the surface of the hole transport layer to obtain the quantum dot light-emitting layer.
In the present invention, the mass concentration of the quantum dot solution is preferably 18 mg/mL. In the present invention, the solvent in the quantum dot solution is preferably n-octane.
In the invention, the quantum dot solution is preferably subjected to pretreatment, in the invention, the pretreatment is preferably impurity removal, in the invention, the TFB solution is preferably filtered to remove large-particle solid impurities, and the filtering pore diameter of the filtering filter membrane is preferably 0.2 μm. The invention preferably adopts a liquid-transferring gun to transfer the quantum dot solution to the surface of the vacancy transmission layer.
In the present invention, the ratio of the mass of the quantum dot solution to the area of the surface of the hole transport layer is preferably 60 μ L/4cm2。
The quantum dot light-emitting layer is obtained by spin coating with a spin coater preferably at 3000rpm for 45 s.
After the quantum light emitting layer is obtained, the invention preferably prepares the electron transport layer on the surface of the quantum light emitting layer.
In the invention, the preparation of the electron transport layer specifically comprises the following steps: and (3) spin-coating the nano zinc oxide solution on the surface of the quantum dot light-emitting layer, and then thermally curing to obtain the electron transmission layer.
In the invention, the mass concentration of the nano zinc oxide solution is preferably 30 mg/mL. In the present invention, the solvent in the nano zinc oxide solution is preferably ethanol.
The nano zinc oxide solution is preferably subjected to pretreatment, in the invention, the pretreatment is preferably impurity removal, in the invention, the nano zinc oxide solution is preferably filtered to remove large-particle solid impurities, and the filtering pore diameter of the filtering filter membrane is preferably 0.2 μm. According to the invention, a liquid-moving gun is preferably adopted to transfer the nano zinc oxide solution to the surface of the quantum dot light-emitting layer.
In the invention, the ratio of the mass of the nano zinc oxide solution to the surface area of the hole injection layer is preferably 60 muL/4 cm2。
The invention preferably adopts a homomixer to carry out spin coating to obtain the nano zinc oxide wet film, the rotation speed of the spin coating is preferably 3000rpm, and the time of the spin coating is preferably 45 s.
After the nano zinc oxide wet film is obtained, the nano zinc oxide wet film is subjected to thermocuring. In the present invention, the temperature of the thermal curing is preferably 60 ℃, the holding time of the thermal curing is preferably 30min, and in the specific implementation of the present invention, the thermal curing is preferably performed in an air environment.
After the thermosetting, the present invention preferably cools the sample after the thermosetting to obtain the electron transport layer, and in the present invention, the cooling is preferably air cooling.
After the electron transmission layer is obtained, the cathode layer is prepared on the surface of the electron transmission layer
In the present invention, the preparation method of the cathode layer is preferably deposition.
In the present invention, the deposition is preferably performed in a vacuum deposition chamber, and the parameters of the deposition are preferably: the degree of vacuum is preferably not more than 1X 10-6mbar, the current of the deposition is preferably 4A/s, and the thickness of the deposition is preferably 100 nm.
After obtaining the cathode layer, the invention preferably uses a mask to limit the contact of the cathode layer, and the effective light-emitting area of the formed quantum dot light-emitting diode device is preferably 0.04cm2。
After the cathode layer is obtained, the preferable sample is encapsulated to obtain the quantum dot light-emitting diode standard device. In the present invention, the encapsulant for encapsulation is preferably an ultraviolet curing agent, more preferably an NOA61 ultraviolet curing agent, and the specific implementation method of the encapsulation is preferably: and (3) curing by adopting an ultraviolet lamp, wherein the curing time is preferably 2-3 min.
After the standard device of the quantum dot light-emitting diode is obtained, the scattering type micro lens is prepared on the back surface of the substrate, and the quantum dot light-emitting diode is obtained.
The scattering type microlens is described above, and will not be described in detail.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
According to the process flow shown in FIG. 1, 350. mu.L of chloroform solution is dripped on a PS substrate of 2cm × 2cm × 1mm at a constant room temperature of 28 ℃ and is left standing in a 60% -65% water vapor environment for 1h, and after the chloroform solution is completely volatilized, a PS template is obtained (as shown in (a) in FIG. 2).
Mixing PDMS and curing agent SYLGARD184(CURING AGENT) according to a mass ratio of 10:1, putting the mixture into a vacuum drying oven for vacuumizing, standing for 1h, discharging air bubbles, taking out the mixture to obtain PDMS casting solution, pouring the treated PDMS casting solution on a PS concave micro-lens template, putting the PS concave micro-lens template into the vacuum drying oven, and heating for 2h at 60 ℃ to completely cure the PDMS casting solution. And after the curing is finished, peeling the PDMS and the PS template to obtain the PDMS flexible template.
The PDMS flexible template is regularly attached to the surface of an IPS polymer substrate, air bubbles are slightly discharged by tweezers and then placed on an objective table on a loading arm of a nano-imprinting machine, and two aluminum sheets with the same size as the objective table are placed on the objective table for protection, so that nano-imprinting can be started. The pressure of the imprinting condition is 20bar, the imprinting temperature and the demolding temperature are respectively selected as 150 ℃ and 100 ℃, the imprinting is kept for 30s, and the IPS template is obtained after the pressure platform is lifted.
Example 2
The preparation method is substantially the same as that provided in example 1, except that the humidity of the water vapor atmosphere is 70% to 75%, and a spheroidal concave microlens template is obtained (as shown in fig. 2 (b)).
Example 3
The preparation method is substantially the same as that provided in example 1, except that the humidity of the water vapor atmosphere is 80% to 85%, to obtain a spheroidal concave microlens template (as shown in fig. 2 (c)).
Example 4
The preparation method is basically the same as that provided in example 1, except that the humidity of the water vapor atmosphere is 90% to 95%, and a spheroidal concave microlens template is obtained (as shown in fig. 2 (d)).
Example 5
Using glass as a substrate (2cm multiplied by 1mm), cleaning the surface of the glass substrate by using ethanol, bonding an ITO layer to obtain an ITO anode layer, and pretreating the surface of the ITO anode layer: cleaning an ITO anode layer, dipping a dust-free cloth in a proper amount of high-temperature detergent to wipe and clean the surface of ITO to remove surface stains, immersing the ITO anode layer into high-temperature cleaning solution, carrying out ultrasonic treatment for 20min at 80 ℃, cooling, sequentially carrying out ultrasonic treatment for 15min in ultrapure water, acetone and isopropanol at room temperature, blowing by nitrogen, and placing into an ultraviolet ozone cleaning instrument for treatment for 15 min.
And (3) spin-coating PEDOT on the surface of the ITO anode layer, wherein PSS: and taking out the rested PEDOT-PSS solution, and filtering the solution by using a filter head with the diameter of a filter hole of 0.45 mu m to remove larger particle impurities in the solution. Dropping a proper amount of PEDOT (PSS) solution on the surface of the cleaned ITO anode layer by using a disposable syringe, and spin-coating for 60s by using a spin coater at the rotating speed of 5000rpm until the solution is formed into a film. And (3) wiping the edge of the ITO/PEDOT (PSS) substrate by using a cotton swab dipped with deionized water to expose the electrode at the edge of the substrate. Then, it was placed on an annealing plate and heated to 150 ℃ and maintained in an air atmosphere for 15min, and the sample was taken out and transferred to a nitrogen glove box insulated from water and oxygen to be cooled, to obtain a hole injection layer.
Spin coating TFB solution on the surface of the vacancy injection layer: first, TFB powder was dissolved in chlorobenzene (8 mg/mL) and placed on a stirrer to stir until the powder was dissolved. Filtering the prepared TFB chlorobenzene solution by using a 0.2-micrometer filter head to remove impurities, then adsorbing a sample on an objective table by using a spin coater, dropwise adding 60-micrometer TFB solution taken out by using a liquid transfer gun at a constant speed in the center of an ITO/PEDOT: PSS substrate with the rotating speed of 3000rpm, placing the ITO/PEDOT: PSS/TFB substrate on an annealing plate to heat to 150 ℃ and maintain 30 mm in a nitrogen environment after the solution is coated for 45s to form a film, and standing and cooling for 20min after the annealing is finished to obtain the hole transport layer.
Spin coating QDs on the surface of the hole transport layer: filtering CdSe @ ZnSQDs solution with a core-shell structure of 18mg/mL by using a PTFE filter head with the diameter of a filter hole of 0.2 mu m, then adsorbing a sample on an objective table by using a spin coater, taking out 60 mu L of the filtered QDs solution by using a pipette gun, dropwise adding the filtered QDs solution at a constant speed to the center of a substrate with the rotating speed of 3000rpm, and spin-coating for 45s to obtain a film. And obtaining the quantum dot light-emitting layer.
And (3) coating ZnO on the surface of the quantum dot light-emitting layer: taking an appropriate amount of ethanol solution of ZnONPs with the concentration of 30mg/mL, filtering impurities by using a filter head with the thickness of 0.2 mu m, taking out 60 mu L of filtered solution by using a pipette, dripping the filtered solution at the center of an ITO/PEDOT (PSS/TFB/QDs) substrate, and spin-coating for 45s at the rotating speed of 3000rpm by using a spin coater until the solution is formed into a film. Then, the edges of the sample were wiped with a cotton swab dipped with a small amount of chlorobenzene or toluene solution to expose the electrodes at the edges of the sample, and then transferred to an annealing plate and heated to 60 ℃ for 30min to obtain an electron transport layer.
Depositing an Al electrode on the surface of the electron transport layer: the sample constructed above is moved to a high vacuum deposition chamber (vacuum degree is less than or equal to 1 × 10)-6mbar), an aluminum cathode thickness was thermally deposited at a rate of 4A/s to 100nm, using a mask to define the top Al contact and form 0.04cm2The effective device light emitting area of (1).
Adding 1-2 drops of NOA61 ultraviolet curing glue on the constructed device, covering a cover glass, and irradiating with an ultraviolet lamp for 2-3 min for curing to obtain the quantum dot light-emitting diode standard device shown in figure 3.
According to the process flow shown in FIG. 4, the particle size is 600nmSiO2Adding 7.5 wt% of nano scattering particles into acetone for ultrasonic dispersion for 30min, adding NOA63 ultraviolet curing glue with the same weight as the acetone, placing magnetons into the mixture, placing the mixture on a magneton stirrer, stirring for 30min, performing ultrasonic treatment for 30min, and repeating the stirring and ultrasonic treatment for 2-3 times respectively to obtain SiO2The nano-scattering particles are uniformly dispersed in the solution. And wiping the back surface of the glass substrate of the packaged standard QLED device with ethanol, placing the glass substrate in an ultraviolet ozone cleaning instrument for 5min with the back surface facing upwards to improve the wettability of the glass surface, and facilitating spin coating. A300. mu.L drop was applied to the back surface of the device glass using a pipette and spin-coated at 1000rpm for 10 seconds to obtain a scattering coating, and an electron micrograph of the scattering coating is shown in FIG. 5 (a).
The IPS template prepared in example 1 is pressed on the back surface of the device on which the scattering solution is spin-coated, the template and the device are clamped by a clamp, the device is placed in a vacuum drying oven and vacuumized for 10min to remove air bubbles between the template and the glass substrate of the device, the device is taken out and irradiated and cured for 15min by a 365nm ultraviolet lamp, the template is peeled off to obtain the scattering type microlens of the scattering type microlens array, and an electron micrograph of the scattering type microlens is shown in fig. 6. Thus, the resulting quantum dot light emitting diode was prepared and is noted as: with SiO2MLAs devices of nano-scattering particles.
Example 6
Essentially the same preparation as provided in example 5, with the exception that the SiO was prepared as described2The mass ratio of the nano scattering particles was 2.5 wt%, and the electron micrograph of the scattering coating layer is shown in fig. 5 (b).
Example 7
Essentially the same preparation as provided in example 5, with the exception that the SiO was prepared as described2The mass ratio of the nano scattering particles was 5 wt%, and the electron micrograph of the scattering coating layer is shown in fig. 5 (c).
Example 8
Essentially the same preparation as provided in example 5, with the exception that the SiO was prepared as described2The mass ratio of the nano scattering particles is 10 wt%, and the electron microscope photograph of the scattering coating is shown in the figure5, (d) in (a).
Example 9
Essentially the same preparation as provided in example 5, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 200 nm.
Example 10
Essentially the same preparation as provided in example 6, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 200 nm.
Example 11
Essentially the same preparation as provided in example 7, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 200 nm.
Example 12
Essentially the same preparation as provided in example 8, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 200 nm.
Example 13
Essentially the same preparation as provided in example 5, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 400 nm.
Example 14
Essentially the same preparation as provided in example 6, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 400 nm.
Example 15
Essentially the same preparation as provided in example 7, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 400 nm.
Example 16
Essentially the same preparation as provided in example 8, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 400 nm.
Example 17
Essentially the same preparation as provided in example 5, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 800 nm.
Example 18
Basic to the preparation method provided in example 6Same, except that the SiO2The particle size of the nano scattering particles is 800 nm.
Example 19
Essentially the same preparation as provided in example 7, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 800 nm.
Example 20
Essentially the same preparation as provided in example 8, with the exception that the SiO was prepared as described2The particle size of the nano scattering particles is 800 nm.
Comparative example 1
Substantially the same preparation method as that provided in example 1, except that 350. mu.L of chloroform was drop-coated on a 2 cm. times.2 cm. times.1 mm PMMA substrate at a constant room temperature of 28 ℃ to obtain a template pattern as shown in (e) of FIG. 7, and no microlens array template was obtained.
Comparative example 2
Substantially the same preparation method as that provided in example 2, except that 350. mu.L of chloroform was applied dropwise to a 2 cm. times.2 cm. times.1 mm PMMA substrate at a constant room temperature of 28 ℃ to obtain a template pattern as shown in (f) of FIG. 7, and no microlens array template was obtained.
Comparative example 3
Substantially the same preparation method as that provided in example 3, except that 350. mu.L of chloroform was drop-coated on a 2 cm. times.2 cm. times.1 mm PMMA substrate at a constant room temperature of 28 ℃ to obtain a template pattern as shown in (g) of FIG. 7, and no microlens array template was obtained.
Comparative example 4
Substantially the same preparation method as that provided in example 4 was conducted except that 350. mu.L of chloroform was applied dropwise to a 2 cm. times.2 cm. times.1 mm PMMA substrate at a constant room temperature of 28 ℃ to obtain a template pattern as shown in (e) of FIG. 7, and no microlens array template was obtained.
Comparative example 5
Substantially the same preparation method as that provided in example 1, except that acetone was coated on a PS substrate of 2cm × 2cm × 1mm, a microlens array template was not obtained.
Comparative example 6
Substantially the same preparation method as that provided in example 1, except that acetone was coated on a 2cm × 2cm × 1mm PMMA substrate, a microlens array template was not obtained.
Comparative example 7
Substantially the same preparation method as that provided in example 1, except that toluene was coated on a PS substrate of 2cm × 2cm × 1mm, a microlens array template was not obtained.
Comparative example 8
Substantially the same preparation method as that provided in example 1, except that toluene was coated on a 2cm × 2cm × 1mm PMMA substrate, a microlens array template was not obtained.
Comparative example 9
Substantially the same preparation method as that provided in example 1, except that the humidity of the water vapor atmosphere was 55%, a microlens array template was not obtained.
Comparative example 10
A standard device of quantum dot light emitting diode (as shown in fig. 3) was prepared in substantially the same manner as the preparation method provided in example 5.
Comparative example 11
The preparation method is basically the same as that provided in example 5, except that the scattering coating is only acetone and NOA63 ultraviolet curing glue with the same weight as the acetone, and SiO is not contained2And (4) nano scattering particles. The obtained quantum dot light emitting diode is recorded as: MLAs devices.
Test example 1
The electrical characteristics and the light extraction efficiency performance of the devices prepared in examples 5 to 20, comparative example 10 and comparative example 11 were tested.
The results of the electrical characteristics test are shown in fig. 8 and 9. FIG. 8 shows three device structures (standard device, MLAs device and with SiO)2Nano scattering particle MLAs device) has a characteristic curve that the power efficiency varies with the current density, compared with a QLED device of a standard structure and an outer structure of a microlens array, the power efficiency is enhanced at the same current density because the material NOA63 used for the microlens array is a uv-curing adhesive with a refractive index similar to that of a glass substrateMost of photons can be emitted into each micro-lens unit, and the outline of each micro-lens unit is similar to a quadratic function parabola, so that the incident angle of light to an air interface can be greatly reduced, and the light extraction efficiency of the substrate is improved.
When SiO with different diameters is doped into each unit of the micro-lens array with different doping amounts2After Mie nanometer scattering particles, the power efficiency is also different, and the comparison shows that when SiO with the diameter of 600nm2After the Mie nano scattering particles are embedded into the micro lens unit in a proportion of 15 wt%, the power efficiency is greatly improved under the same current density, and the maximum power efficiency is improved from 73.34lm/W to 94.92lm/W of a standard device. The reason is that 600nm of SiO2The wavelength of the nano scattering particles is similar to that of a green light device, the Mie scattering intensity of light in the micro lens unit is enhanced, and meanwhile, the top of the device is packaged by a reflector, so that a small part of light caused by the nano scattering particles is scattered backwards and is reflected back to the bottom of the device to emit light.
Fig. 9 compares the current density and external quantum efficiency of the three device structures with the voltage change, and the current density and voltage change curves of the three device structures are basically overlapped, because the electrical characteristics of the device are mainly influenced by the electron mobility and energy level barrier inside the device, the scattering type microlens introduced by the invention does not damage the functional layer inside the QLED device, and the electrical characteristics of the device are not changed when the scattering type microlens is added or not. The scattering type microlens increases the light extraction efficiency of the device while the current density is unchanged, so that SiO is provided2The maximum external quantum efficiency of the green light QLED device of the micro-lens array of the nano scattering particles reaches 25.11 percent, and is improved by 21 percent compared with a standard device with the maximum external quantum efficiency of 20.74 percent.
FIG. 10 is EL lines of three devices measured at different angles, wherein (a) in FIG. 10 is a standard device of comparative example 10, (b) in FIG. 10 is an MLAs device prepared in comparative example 11, and (c) in FIG. 10 is MLAs and SiO prepared in example 12Normalizing the EL spectrum of the device under different angles; fig. 10 (d) shows the angular emission spectra of three device structures and lambertian bodies.
As can be taken from figure 10 of the drawings,with SiO2The MLAs device (example 1) with nanometer scattering particles has higher coincidence ratio of spectral lines at the two sides of the 534nm peak value under the angles of 30 degrees, 60 degrees and 90 degrees, which shows that SiO2The nanometer scattering particles can enable the electroluminescent color of the device to be more stable under various angles. Comparative example 11 introduction of the microlens array structure can improve the light extraction efficiency, but can cause the light extraction of the device to show a more obvious angle-dependent characteristic, as shown in (d) of fig. 10, SiO2The incorporation of the material into the microlens element improves this disadvantage, making the light output of the device more lambertian.
The detection method for implementing the QLED device comprises efficiency detection and software simulation, wherein the efficiency detection utilizes an integrating sphere to carry out performance test; the software simulation is used for modeling and analyzing the longitudinal electromagnetic field distribution of the device by using an FDTDSeolutions time domain finite difference method, and is used for modeling and analyzing the transverse light distribution of the device substrate by using a Lighttools Monte Carlo ray tracing method. As shown in FIG. 11, (a) in FIG. 11 is a standard device, (b) in FIG. 11 is an MLAs device, and (c) in FIG. 11 is an MLAs and SiO2A device. As can be seen from fig. 11, the FDTD simulates the longitudinal electromagnetic field distribution, because the critical angle of total reflection at the interface between the glass substrate and the air of the standard device is too small, a large amount of light is bound inside the device, and an electromagnetic field accumulation phenomenon appears; the introduced external structure can greatly reduce the accumulation of an internal electromagnetic field, meanwhile, the electromagnetic field emitted by the device to the air is stronger, the electromagnetic field distribution of the MLAs structure device prepared in the embodiment 11 at the interface is triangular from the enlarged image at the interface, and the problem of angle dependence of the MLAs device prepared in the embodiment 11 is also verified, and SiO is introduced into an MLAs unit2The Mie nano scattering particles can greatly improve the angle dependence of the device.
The invention adopts Lighttools to simulate and track 500000 light rays emitted from the interior of the device, as shown in FIG. 12, (a) in FIG. 12 is a standard device, (b) in FIG. 12 is an MLAs device, and (c) in FIG. 12 is MLAs and SiO2Device, as can be seen from fig. 12, Lighttools simulate that the area of light spot at the interface between the luminance substrate and the air at the lateral substrate is gradually increased, the luminance is gradually softened, and the peak luminance is not attenuated, which shows thatWith SiO2The outer structure of the micro-lens array of the Mie nano scattering particles can effectively extract light out of the substrate.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. The concave microlens array template is characterized in that the concave transparent array template is a polystyrene concave microlens array template, a polydimethylsiloxane concave microlens array template or an impact-resistant polystyrene concave microlens array template, the surface of the concave microlens array template is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is more than or equal to 5 micrometers independently, and the height of the top point of the quasi-hemispherical array is more than or equal to 2 micrometers independently.
2. The method of preparing a concave microlens array template according to claim 1, wherein the method of preparing a polystyrene concave microlens array template comprises:
standing a polystyrene substrate coated with trichloromethane in a water vapor atmosphere to obtain a polystyrene concave micro-lens array template, wherein the humidity of the water vapor atmosphere is more than or equal to 60%, the temperature of the water vapor atmosphere is 25-30 ℃, and the surface of the polystyrene substrate coated with trichloromethane is horizontally placed upwards;
the preparation method of the polydimethylsiloxane concave micro-lens array template comprises the following steps:
pouring the polydimethylsiloxane casting solution into the polystyrene concave micro-lens array template, and performing thermal curing and demolding in sequence to obtain the polydimethylsiloxane concave micro-lens array template;
the preparation method of the impact-resistant polystyrene concave micro-lens array template comprises the following steps:
and imprinting the polydimethylsiloxane concave micro-lens array template with an impact-resistant polystyrene film to obtain the impact-resistant polystyrene micro-lens array template.
3. A scattering type micro lens is characterized by comprising a scattering type micro lens array surface, wherein the chemical composition of the scattering type micro lens comprises nanometer scattering particles and a curing agent, the scattering type micro lens array surface is a quasi-hemispherical array, the diameter of the quasi-hemispherical array is not less than 5 mu m independently, and the height of the top point of the quasi-hemispherical array is not less than 2 mu m independently.
4. A scattering-type microlens as claimed in claim 3, wherein the nano-scattering particles comprise SiO2、TiO2And Al2O3One or more of; the particle size of the nano scattering particles is 200-800 nm.
5. A scattering-type microlens as claimed in claim 3 or 4, wherein the nano-scattering particles are present in the scattering-type microlens in an amount of 5 to 20% by mass.
6. A scattering-type microlens as claimed in claim 3, wherein the thickness of the scattering-type microlens is ≦ 10 μm.
7. A substrate comprising a base and a diffusing microlens provided on the back surface of the base, wherein the diffusing microlens is the diffusing microlens according to claim 3 to 6.
8. A method for preparing a substrate as claimed in claim 7, characterized by comprising the steps of:
coating scattering liquid on the back surface of the substrate to obtain a scattering coating, wherein the scattering liquid comprises nanometer scattering particles, a curing agent and a polar organic solvent;
and (2) stamping the scattering coating by using a template, curing, and demolding to obtain the substrate, wherein the template is the concave micro-lens array template as claimed in claim 1.
9. Use of the substrate according to claim 8 or the substrate prepared by the preparation method according to claim 9 in a light emitting diode lighting device.
10. A quantum dot light-emitting diode, comprising a substrate, and an anode layer, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode layer which are sequentially arranged on the surface of the substrate, wherein the back of the substrate is provided with the scattering type microlens as claimed in any one of claims 3 to 6.
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