CN111554819A - Light emitting device, light emitting color adjusting method thereof and display device - Google Patents

Abstract

The present application relates to a light-emitting device, a method for adjusting light-emitting color thereof, and a display device, including a substrate, a first electrode, a first light-emitting unit, a second electrode, a second light-emitting unit, and a third electrode. One of the first light-emitting unit and the second light-emitting unit is a color changing unit, and the other is a color fixing unit, and the light-emitting color of the color changing unit changes with the change of the driving voltage parameter. By changing the connection mode of the second electrode, the first electrode and the third electrode and the power supply, the first light-emitting unit and the second light-emitting unit can work at the same time, and the light-emitting device can realize high-efficiency, high-brightness white light emission with the change of the driving voltage parameters. ; Or make the first light-emitting unit and the second light-emitting unit work alternately, and make the light-emitting device have a full-color tunable light-emitting color along with the change of the driving voltage parameter. At the same time, the light-emitting layers of the first light-emitting unit and the second light-emitting unit do not need to be patterned, and it is easy to realize high-resolution and large-area display.

Description

Light-emitting device, method for adjusting light-emitting color thereof, and display device

technical field

The present application relates to the field of light-emitting diodes, and in particular, to a light-emitting device, a method for adjusting light-emitting color thereof, and a display device.

Background technique

With the development of quantum dot materials and the advancement of device fabrication processes, quantum dot light-emitting diodes (Quantum Dot Light Emitting Diodes, QLED) have made great progress in performance, such as efficiency, brightness, and lifetime. There are still obstacles in the application: to achieve full-color QLED display, the light-emitting layer needs to be patterned, but the quantum dot pixel patterning technology is immature. For example, the inkjet printing technology has poor film quality, low resolution, and poor uniformity. Resolution and large-area display; in order to avoid the aforementioned problems, the method of superimposing color filters can be used to achieve full-color display, but it is necessary to use color filter filters to filter white light to restore the three primary colors of red, green, and blue. The loss of white light is large and the efficiency Low.

Therefore, the practical application of QLED in full-color displays has the problems of large white light loss, low efficiency, and difficulty in realizing high-resolution and large-area display.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a light-emitting device, a method for adjusting light-emitting color, and a display device, which can realize high-resolution and large-area display, can adjust the light-emitting color in full color, and can obtain high-efficiency white light emission.

A light-emitting device, comprising:

base;

A first electrode, a first light-emitting unit, a second electrode, a second light-emitting unit and a third electrode are sequentially stacked on the substrate; wherein:

the second electrode is a transparent conductive electrode;

One of the first light-emitting unit and the second light-emitting unit is a color changing unit, and one of the first light-emitting unit and the second light-emitting unit is a color fixing unit, and the color changing unit includes a first light-emitting unit. A quantum dot light-emitting layer, the light-emitting color of the first quantum dot light-emitting layer changes with the change of the driving voltage parameter.

In one of the embodiments, the first quantum dot light-emitting layer includes a red quantum dot light-emitting layer and a green quantum dot light-emitting layer arranged in layers; or

The material of the first quantum dot light-emitting layer includes a mixed light-emitting material of red quantum dots and green quantum dots.

In one embodiment, the first light-emitting unit is the color changing unit, and the color changing unit further includes:

a first hole injection layer, stacked on the side of the first electrode away from the substrate;

The first hole transport layer is stacked on the side of the first hole injection layer away from the substrate, and the first quantum dot light-emitting layer is stacked on the side of the first hole transport layer away from the substrate. one side;

The first electron transport layer is stacked on the side of the first quantum dot light-emitting layer away from the substrate.

In one of the embodiments, the color fixing unit includes a second quantum dot light-emitting layer or an organic light-emitting layer.

In one embodiment, the material of the second quantum dot light-emitting layer includes a blue quantum dot light-emitting material, and the material of the organic light-emitting layer includes a blue organic light-emitting material.

In one embodiment, the color fixing unit further includes:

A second hole injection layer, a second hole transport layer, a second electron transport layer, and an electron injection layer; wherein:

The second hole injection layer and the second hole transport layer are sequentially stacked and arranged on the side of the second electrode away from the substrate;

The second quantum dot light-emitting layer or the organic light-emitting layer is stacked on the side of the second hole transport layer away from the substrate;

The second electron transport layer and the electron injection layer are sequentially stacked and disposed on the side of the second quantum dot light-emitting layer or the organic light-emitting layer away from the substrate.

In one embodiment, the material of the second electrode includes a transparent conductive oxide; and/or the thickness of the second electrode is 50 nm-120 nm.

In one of the embodiments, at least one of the first electrode and the third electrode is a transparent electrode.

In one embodiment, the material of the transparent electrode includes one of transparent conductive oxide and conductive metal.

In one of the embodiments, the light emitting device further comprises:

A sputtering buffer layer is provided between the first light emitting unit and the second electrode.

In one embodiment, the sputter buffer layer includes a stack of one or both of a metal layer and a ZnO-based nanoparticle layer.

In one embodiment, the thickness of the metal layer is 1 nm-5 nm, and the thickness of the ZnO-based nanoparticle layer is 40 nm-100 nm.

A light-emitting color adjustment method for adjusting the light-emitting color of the above-mentioned light-emitting device, comprising:

Connect the first electrode and the third electrode to the first end of the AC power supply after short-circuiting, and connect the second electrode to the second end of the AC power supply;

Adjust the driving voltage parameter of the AC power source to adjust the light-emitting color of the light-emitting device; or

connecting the first electrode with the first end of the DC power supply, and connecting the third electrode with the second end of the DC power supply;

The driving voltage parameter of the DC power supply is adjusted to adjust the light-emitting color of the light-emitting device.

A display device includes the light-emitting device as described above.

The above-mentioned light-emitting device, a method for adjusting light-emitting color thereof, and a display device include a substrate, a first electrode, a first light-emitting unit, a second electrode, a second light-emitting unit, and a third electrode. Wherein, one of the first light-emitting unit and the second light-emitting unit is a color changing unit, and one of the first light-emitting unit and the second light-emitting unit is a color fixing unit, and the light-emitting unit of the color changing unit The color changes with the drive voltage parameter. By changing the connection mode between the second electrode, the first electrode and the third electrode and the power supply, on the one hand, DC voltage driving can be realized, so that the first light-emitting unit and the second light-emitting unit can work at the same time. The device realizes high-efficiency, high-brightness white light emission, which can be applied to white light illumination; on the other hand, it can realize AC voltage driving, so that the first light-emitting unit and the second light-emitting unit work in turn, and with the change of driving voltage parameters, the light-emitting device has Full-color tunable luminous color, which can be applied to full-color displays. At the same time, the light-emitting layers of the first light-emitting unit and the second light-emitting unit do not need to be patterned, and it is easy to realize high-resolution and large-area display.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a light-emitting device in one embodiment;

2 is a schematic structural diagram of a light-emitting device in one embodiment;

3 is a schematic structural diagram of a light-emitting device in one embodiment;

4 is a schematic structural diagram of a first light-emitting unit in an embodiment;

5 is a schematic structural diagram of a second light-emitting unit in one embodiment;

6 is a schematic structural diagram of a light-emitting device in one embodiment;

FIG. 7 is a flow chart of a method for adjusting the emission color of a light-emitting device in one embodiment;

8 is a schematic diagram of a specific structure of a light-emitting device in an embodiment;

9 is a schematic circuit diagram of an AC-driven light-emitting device in one embodiment;

10 is a schematic circuit diagram of a DC-driven light-emitting device in one embodiment;

11 is a schematic diagram of an electroluminescence spectrum of a light-emitting device driven by an alternating current and corresponding CIE coordinates and driving signals in one embodiment;

12 is a color gamut diagram that can be achieved by a light-emitting device in one embodiment;

FIG. 13 is an electroluminescence spectrogram of a light-emitting device driven by direct current in one embodiment;

FIG. 14 is a current density-voltage-brightness characteristic curve diagram of a light-emitting device under DC driving in one embodiment;

FIG. 15 is a graph showing the external quantum efficiency-current density characteristic of the light-emitting device under direct current driving in one embodiment.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

It will be understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first electrode may be referred to as a second electrode, and similarly, a second electrode may be referred to as a first electrode, without departing from the scope of this application. Both the first electrode and the second electrode are electrodes, but they are not the same electrode.

Referring to FIG. 1 , FIG. 1 shows a schematic structural diagram of a light emitting device provided in this embodiment.

In this embodiment, the light emitting device 10 includes: a substrate 101 ; a first electrode 102 , a first light emitting unit 103 , a second electrode 104 , a second light emitting unit 105 , and a third electrode 106 , which are sequentially stacked on the substrate 101 .

In this embodiment, the base 101 may be a glass substrate, or a ceramic substrate or a plastic flexible substrate may be selected according to actual conditions.

In this embodiment, the first electrode 102, the second electrode 104 and the third electrode 106 are used in combination: in one embodiment, the second electrode 104 can be used as the first control electrode of the light-emitting device and the first end of the AC power supply connection, the first electrode 102 and the third electrode 106 are short-circuited as the second control electrode of the light-emitting device is connected to the second end of the AC power supply, so that the first light-emitting unit 103 and the second light-emitting unit 105 are connected in antiparallel (see 2), to realize AC voltage driving, at this time, the first light-emitting unit 103 and the second light-emitting unit 105 work in turn, so that the light-emitting device has a full-color tunable light-emitting color. In another embodiment, the second electrode 104 is a transparent conductive electrode, and has an energy level matching the first light-emitting unit 103 and the second light-emitting unit 105. As an intermediate connection layer of the stack, the first light-emitting unit 103 and the The two light-emitting units 105 are connected, and the first electrode 102 and the third electrode 106 are respectively connected to both ends of the DC power supply, so that the first light-emitting unit 103 and the second light-emitting unit 105 are effectively connected in series (refer to FIG. DC voltage driving, at this time, the first light-emitting unit 103 and the second light-emitting unit 105 work simultaneously, so that the light-emitting device can achieve high-efficiency, high-brightness white light emission.

In one embodiment, the material of the second electrode 104 includes a transparent conductive oxide, such as one of indium-doped tin oxide (ITO), aluminum-doped zinc oxide (AZO), and indium-doped zinc oxide (IZO) or various, so that the second electrode 104 has good light transmittance and conductivity; in one embodiment, the thickness of the second electrode 104 is 50nm-120nm, so that it has good electrical performance and high electrical performance. transmittance. More specifically, when AC driving, the light-emitting device is used as a color-changing device to realize full-color tunable function of light-emitting color, and the thickness of the second electrode 104 can be set to be 50nm-120nm; For high-brightness white light emission, the thickness of the second electrode 104 can be set to 50nm-120nm.

In one embodiment, at least one of the first electrode 102 and the third electrode 106 is a transparent electrode, and the material of the transparent electrode includes one of transparent conductive oxide and conductive metal. Specifically, when only the first electrode 102 is a transparent electrode, the light-emitting device can be formed as a bottom-emitting device; when only the third electrode 106 is a transparent electrode, the light-emitting device can be formed as a top-emitting device, compared with bottom-emitting devices , higher luminous power can be obtained under the same current density; when both the first electrode 102 and the third electrode 106 are transparent electrodes, the light-emitting device is a transparent light-emitting device, which can be applied to a transparent display. Therefore, light-emitting devices of different emission types can be formed by selecting the materials of the first electrode 102 and the third electrode 106, so as to expand the actual demand of the light-emitting device and be suitable for more display occasions.

The transparent conductive oxide includes one or more of indium-doped tin oxide (ITO), aluminum-doped zinc oxide (AZO), and indium-doped zinc oxide (IZO); conductive metals include silver and silver-magnesium alloys. One or more of them, such as one or more of Ag nanowires, thin-layer Ag, thin-layer Ag:Mg and other metal nanowires, and thin-layer metals.

In this embodiment, one of the first light emitting unit 103 and the second light emitting unit 105 is a color changing unit, and one of the first light emitting unit 103 and the second light emitting unit 105 is a color fixing unit, and the color changing unit includes The first quantum dot light-emitting layer, the light-emitting color of the first quantum dot light-emitting layer changes with the change of the driving voltage parameter.

Wherein, the color changing unit can change the light emission color with the driving voltage parameter of the power supply, for example, emit red light, yellow light or green light with the change of the driving voltage parameter; the color fixing unit maintains the same color with the driving voltage, for example, with the driving voltage Changes in parameters remain blue. Among them, the driving voltage parameters include voltage amplitude, duty cycle and frequency, usually the frequency is above 50HZ. Therefore, through the combination of the color changing unit and the color fixing unit, light of different colors can be mixed in different proportions, so that the light-emitting device has a fully-color-tunable light-emitting color, and high-efficiency white light emission can also be realized. At the same time, the light-emitting layers of the first light-emitting unit and the second light-emitting unit do not need to be patterned, and it is easy to realize high-resolution and large-area display.

Exemplarily, the first light-emitting unit 103 is a color changing unit, and the second light-emitting unit 105 is a color fixing unit:

In one embodiment, the first light-emitting unit 103 is a single-functional layer structure, including a first quantum dot light-emitting layer, and the first quantum dot light-emitting layer is disposed between the first electrode 102 and the second electrode 104, so as to achieve thin light emission unit, which effectively simplifies the fabrication process of the light-emitting device.

In one embodiment, the first light emitting unit 103 is a multifunctional layer structure, so as to further improve the optoelectronic properties. Referring to FIG. 4 , the first light-emitting unit 103 includes a first quantum dot light-emitting layer 301 , and further includes: a first hole injection layer 302 , a first hole transport layer 303 and a first electron transport layer 304 . The first hole injection layer 302 is stacked on the side of the first electrode away from the substrate; the first hole transport layer 303 is stacked on the side of the first hole injection layer 302 away from the substrate; the first quantum dots The light-emitting layer 301 is stacked on the side of the first hole transport layer 303 away from the substrate 101 ; the first electron transport layer 304 is stacked on the side of the first quantum dot light-emitting layer 301 away from the substrate.

The materials and thicknesses of the respective functional layers of the first hole injection layer 302 , the first hole transport layer 303 and the first electron transport layer 304 are not limited here, as long as the functions of the respective functional layers can be realized. At the same time, the first light-emitting unit can also increase the functional layer or reduce the functional layer according to the actual situation.

In one embodiment, the second light-emitting unit 105 has a single-functional layer structure, including a second quantum dot light-emitting layer or an organic light-emitting layer, thereby realizing a thin light-emitting unit and effectively simplifying the fabrication process of the light-emitting device.

In one embodiment, the second light-emitting unit 105 is a multifunctional layer structure, so as to further improve the optoelectronic properties. Referring to FIG. 5, the second light-emitting unit 105 includes a second quantum dot light-emitting layer or an organic light-emitting layer 401, and further includes: a second hole injection layer 402, a second hole transport layer 403, a second electron transport layer 404, and an electron transport layer 402. Implant layer 405 . The second hole injection layer 402 and the second hole transport layer 403 are stacked on the side of the second electrode 104 away from the substrate in sequence; the second quantum dot light-emitting layer or the organic light-emitting layer 401 is stacked on the second hole transport layer. The layer 403 is on the side away from the substrate; the second electron transport layer 404 and the electron injection layer 405 are sequentially stacked on the side away from the substrate of the second quantum dot light-emitting layer or the organic light-emitting layer 401 .

The materials and thicknesses of the functional layers of the second hole injection layer 402 , the second hole transport layer 403 , the second electron transport layer 404 and the electron injection layer 405 are not limited here, as long as the functions of each functional layer can be realized That's it. At the same time, the second light-emitting unit 105 can also add functional layers (eg, add an electron blocking layer between the organic light-emitting layer and the second hole transport layer) or reduce the functional layers in the second light-emitting unit 105 according to the actual situation.

In one embodiment, the first quantum dot light-emitting layer includes a stacked red quantum dot light-emitting layer and a green quantum dot light-emitting layer; or the material of the first quantum dot light-emitting layer includes a mixed light-emitting material of red quantum dots and green quantum dots. Therefore, through the red quantum dots and the green quantum dots, the light-emitting color of the first quantum dot light-emitting layer changes with the change of the driving voltage parameter.

In one embodiment, the material of the second quantum dot light-emitting layer includes a blue quantum dot light-emitting material, and the material of the organic light-emitting layer includes a blue organic light-emitting material. Therefore, the blue quantum dot light-emitting material of the second quantum dot light-emitting layer realizes blue light emission under voltage driving, and the blue organic light-emitting material of the organic light-emitting layer realizes blue light emission under voltage driving. Among them, the blue quantum dot light-emitting material has a better color gamut than the blue organic light-emitting material.

In one embodiment, the quantum dot light-emitting material includes at least one of CdSe-based nano-luminescent material and InP-based nano-luminescent material; the organic light-emitting material includes at least one of organic phosphorescent light-emitting material, organic fluorescent light-emitting material, and organic delayed fluorescence light-emitting material A sort of.

It should be noted that the formation processes of the above-mentioned layers are not limited, and include formation processes such as laser etching, spin coating, evaporation, radio frequency magnetron sputtering, thermal evaporation, and all-solution methods. For example, the substrate is patterned by laser etching, the first electrode and the second electrode are deposited by sputtering, the functional layers of the first light-emitting unit and the second light-emitting unit are deposited by spin coating, and the third electrode is deposited by thermal evaporation. . It can be understood that the forming process can be selected and adjusted according to the actual application and product performance, which is not further limited herein.

The light-emitting device provided in this embodiment includes a substrate, a first electrode, a first light-emitting unit, a second electrode, a second light-emitting unit, and a third electrode. Wherein, one of the first light-emitting unit and the second light-emitting unit is a color changing unit, and one of the first light-emitting unit and the second light-emitting unit is a color fixing unit, and the light-emitting color of the color changing unit varies with the driving voltage parameter. Variety. By changing the connection mode of the second electrode, the first electrode and the third electrode and the power supply, on the one hand, DC voltage driving can be realized, so that the first light-emitting unit and the second light-emitting unit can work at the same time. High-efficiency, high-brightness white light emission, which can be applied to white light illumination; on the other hand, it can realize AC voltage driving, so that the first light-emitting unit and the second light-emitting unit work in turn, and with the change of driving voltage parameters, the light-emitting device has full color Adjustable luminous color, can be applied to full color display. At the same time, the light-emitting layers of the first light-emitting unit and the second light-emitting unit do not need to be patterned, and it is easy to realize high-resolution and large-area display.

Referring to FIG. 6 , on the basis of FIG. 1 , FIG. 6 shows a schematic structural diagram of another light emitting device provided in this embodiment.

In this embodiment, the light-emitting device 20 includes: a substrate 201; a first electrode 202, a first light-emitting unit 203, a second electrode 204, a second light-emitting unit 205, and a third electrode 206 stacked on the substrate 201 in sequence; a light-emitting device It also includes a sputtering buffer layer 207 disposed between the first light-emitting unit 203 and the second electrode 204 to protect the first light-emitting unit 203 from being damaged when the second electrode 204 is prepared by sputtering.

In one embodiment, the sputter buffer layer 207 includes a stack of one or both of a metal layer and a ZnO-based nanoparticle layer. Since the metal and ZnO-based nanoparticles have electrical conductivity, which is beneficial to the transfer of charges, the sputtering buffer layer 207 resists the bombardment of the second electrode 204 during sputtering and prevents the penetration of atoms. performance and optical performance are negatively affected. Therefore, the sputtering buffer layer 207 in this embodiment can protect the first light emitting unit 203 while improving the optoelectronic performance of the first light emitting unit 203, thereby further improving the stability and optoelectronic performance of the light emitting device.

In one embodiment, the thickness of the metal layer is 1nm-5nm, and the metal layer can be an Al layer, such as an Al ultra-thin metal film, so as to protect the first light-emitting unit and further improve the photoelectric performance of the first light-emitting unit; ZnO-based The thickness of the nanoparticle layer is 40 nm-100 nm, so that the photoelectric performance of the first light emitting unit can be further improved while protecting the first light emitting unit.

It should be noted that, for the substrate 201 , the first electrode 202 , the first light-emitting unit 203 , the second electrode 204 , the second light-emitting unit 205 and the third electrode 206 , please refer to the substrate 101 , the first electrode 102 , the first The related descriptions of a light-emitting unit 103 , the second electrode 104 , the second light-emitting unit 105 and the third electrode 106 will not be repeated here.

Referring to FIG. 7 , FIG. 7 shows a flowchart of the method for adjusting the light emission color of the light emitting device provided by the above embodiment. The adjustment method includes steps 701 to 704 . specifically:

In step 701, the first electrode and the third electrode are short-circuited and then connected to the first end of the AC power source, and the second electrode is connected to the second end of the AC power source.

Step 702: Adjust the driving voltage parameter of the AC power supply to adjust the light-emitting color of the light-emitting device.

Step 703: Connect the first electrode to the first end of the DC power supply, and connect the third electrode to the second end of the DC power supply.

Step 704: Adjust the driving voltage parameter of the DC power supply to adjust the light-emitting color of the light-emitting device.

In this embodiment, through steps 701 to 702, the light-emitting device can have a full-color tunable light-emitting color. For the specific connection method of each electrode of the light-emitting device, please refer to FIG. 2 of the above-mentioned embodiment, which will not be repeated here; Steps 703 to 704 can enable the light-emitting device to achieve high-efficiency and high-brightness white light emission. For the specific connection method of each electrode of the light-emitting device, please refer to FIG.

It should be understood that, although the steps in the flowchart of FIG. 7 are sequentially displayed in accordance with the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, the execution of these steps is not strictly limited to the order, and these steps may be performed in other orders.

The following are specific implementations in the above-mentioned embodiments. It should be noted that the above-mentioned embodiments are not limited to the following specific embodiments, and can be appropriately modified and implemented within the scope of not changing the main rights:

Example 1

FIG. 8 is a schematic structural diagram of the light emitting device provided in this embodiment.

The light-emitting device is provided with a glass substrate 801 , a first electrode 802 , a first light-emitting unit 803 , a sputtering buffer layer 804 , a second electrode 805 , a second light-emitting unit 806 and a third electrode 807 stacked sequentially from bottom to top.

The first light-emitting unit 803 is a color-changing unit, and is a QLED with adjustable color, including a hole injection layer 8031, a hole transport layer 8032, a first quantum dot light-emitting layer 8033 and an electron transport layer 8034; the second light-emitting unit 806 is a color fixing unit, and is a fluorescent blue OLED, including a hole injection layer 8061 , a hole transport layer 8062 , an organic light-emitting layer 8063 , an electron transport layer 8064 and an electron injection layer 8065 .

The glass substrate 801 and the first electrode 802 (transparent electrode) are ITO glass substrates patterned by laser ablation or photolithography.

The hole injection layer 8031 is a poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)(PEDOT:PSS) film, and the preparation method is as follows: The PEDORT:PSS solution was spin-coated at 3000 r/min to form a film, and then baked at 150 °C for 15 min. The hole transport layer 8032 is poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-ALT-(9,9-diamine) n-Octylfluorenyl-2,8-diyl)]Poly[(9,9-dioctylfluorenyl-2,8-diyl)-co(4,4-(N-(p-butylphenyl))diphenylamine)]

(TFB) thin film, the preparation method is as follows: spin-coating a chlorobenzene solution of 8 mg/ml TFB at a rotational speed of 3000 r/min to form a film, and then bake at 110° C. for 10 min.

The first quantum dot light-emitting layer 8033 is a mixed film of red quantum dots and green quantum dots with a CdSe/ZnS core-shell structure. The n-octane solution of quantum dots is configured into a mixed solution of red quantum dots and green quantum dots with a ratio of 1:20 (color-changing device) or 1:9 (white light device) according to different volume ratios, and rotates at 3000r/min. The films were spin-coated and then baked at 100 °C for 5 min.

Among them, the electron transport layer 8034 is a ZnMgO nanoparticle film, and the preparation method is as follows: spin-coating an ethanol solution of 20mg/ml ZnMgO nanoparticle at a speed of 2500r/min to form a film, and then bake at 100°C for 10min.

The sputtering buffer layer 804 is a 2nm Al ultra-thin metal film prepared by evaporation method; the second electrode 805 is a 60nm (color-changing light-emitting device) or 80nm (white light-emitting device) IZO transparent oxide prepared by sputtering method material film.

The material of the hole injection layer 8061 is molybdenum trioxide (MoO ₃ ) with a thickness of 8 nm; the material of the hole transport layer 8062 is N,N'-[bis(1-naphthyl)-N,N'-di Phenyl]-1,1'-biphenyl)-4,4'-diamineN,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4, 4″-diamine(NPB), thickness is 45nm; the material of organic light-emitting layer 8063 is 9,10-bis(2-naphthyl)-2-methylanthracene 2-methyl-9,10-di(2-naphthyl) anthracene (MADN) and 4,4′-[1,4-phenylenebis-(1E)-2,1-ethylenediyl]bis[N,N-diphenylaniline]9,10-p-bis The mixed film of (pN,N-diphenyl-aminostylyl)benzene(DSA-Ph) (DSA-Ph/MADN=12%), its thickness is 25nm; the material of electron transport layer 8064 is 2,2′,2″-( 1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole (TPBi), with a thickness of 40 nm; the electron injection layer 8065 is made of lithium fluoride (LiF) with a thickness of 1 nm.

The third electrode 807 is a 100 nm Al electrode prepared by thermal evaporation.

Please refer to FIG. 9-FIG. 10. FIG. 9 is a schematic circuit diagram of an AC-driven light-emitting device provided in this embodiment, and FIG. 10 is a circuit schematic diagram of a DC-driven light-emitting device provided by this embodiment.

Please refer to FIG. 11-FIG. 12. FIG. 11 is a schematic diagram of an electroluminescence spectrum of the light-emitting device provided in this embodiment driven by an alternating current, as well as the corresponding CIE coordinates and driving signals; Implemented color gamut map.

It can be seen from Fig. 11-Fig. 12 that the luminous color of the device can be changed from red to green, green to blue, blue to red and blue to Variations of orange, achievable color gamut up to 63% NTSC.

Please refer to FIG. 13-FIG. 15. FIG. 13 shows the electroluminescence spectrum of the light-emitting device provided in this embodiment under DC driving; FIG. 14 shows the current density-voltage-voltage of the light-emitting device provided in this embodiment under DC driving Brightness characteristic curve diagram; FIG. 15 is a characteristic curve diagram of external quantum efficiency-current density of the light-emitting device provided in this embodiment under DC driving.

It can be seen from the figure that when the light-emitting device is driven by a DC power supply, parameters such as the emission spectrum, current-voltage characteristics and external quantum efficiency of the first light-emitting unit (red-green QLED) and the second light-emitting unit (blue OLED) are obtained. The good superposition (stacked white light) indicates that the second electrode has excellent electrical properties and can well connect the first light-emitting unit and the second light-emitting unit in series. The light-emitting device successfully achieved a high-brightness white light emission of 107K ^cd /m2 and a high external quantum efficiency of 16.91%.

Example 2

The only difference between this embodiment and Embodiment 1 is that the second light-emitting unit is a phosphorescent blue OLED, which includes a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, an electron transport layer and an electron layer that are stacked in sequence. The injection layer is prepared by thermal evaporation.

Among them, the material of the hole injection layer is 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene dipyrazino[2,3-f : 2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HATCN) with a thickness of 20 nm. The material of the hole transport layer is 1,1-bis[4-[N,N-bis(p-toluene)amino]phenyl]cyclohexane 1,1-bis[4-[N,N-di(p- tolyl)aminophenyl]cyclohexane (TAPC) with a thickness of 40 nm. The material of the electron blocking layer is 1,3-dicarbazol-9-ylbenzene 1,3-bis(9-carbazolyl)benzene(mCP), and the thickness is 5 nm. The material of the organic light-emitting layer is bis(4,6-difluorophenylpyridine-C2,N)picolinoyl iridium Bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III )(Firpic) and 9-(3-(9H-carbazole-9-yl)phenyl)-3-(dibromophenylphosphoryl)-9H-carbazole(mCPPO1) hybrid film (Firpic/mCPPO1=8%) with a thickness of 30 nm . The material of the electron transport layer is 1,3,5-tris[(3-pyridinyl)-3-phenyl]benzene 1,3,5-Tri(m-pyridin-3-ylphenyl)benzene)(TmPyPB), thickness is 30nm. The material of the electron injection layer is lithium fluoride (LiF), and the thickness is 1 nm.

Compared with the fluorescent blue OLED of Example 1, the phosphorescent blue OLED used in the second light-emitting unit of Example 2 has higher luminous efficiency, so that the overall luminous efficiency of the light-emitting device is higher.

Example 3

The only difference between this embodiment and Embodiment 1 is that the first electrode is a reflective electrode based on Al/ITO, prepared by sputtering; the third electrode is a transparent electrode, using Ag:Mg thin-layer metal with a thickness of 15 nm, using Evaporation production.

Compared with the bottom emission device of Example 1, Example 3 is a top emission device, which has a larger aperture ratio and can obtain higher luminous power under the same current density.

Example 4

The only difference between this embodiment and Embodiment 1 is that the second electrode is an ITO film with a thickness of 60 nm to 80 nm, which is prepared by sputtering.

Compared with the IZO transparent oxide film of the second electrode in Example 1, the ITO film used in the second electrode in Example 4 also has excellent light transmittance and electrical conductivity, so that the overall device has higher luminous efficiency and optoelectronic properties. .

Example 5

The only difference between this embodiment and Embodiment 1 is that the second light-emitting unit is a blue QLED, including a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, and an electron transport layer that are stacked in sequence, and are prepared by a full solution method. .

The material of the hole injection layer is poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)(PEDOT:PSS), and the preparation method is as follows: The PEDORT:PSS solution was spin-coated at 3000 r/min to form a film, and then baked at 150 °C for 15 min. The material of the hole transport layer is poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-ALT-(9,9- Di-n-octylfluorenyl-2,7-diyl)]Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co(4,4-(N-(p-butylphenyl))diphenylamine)]( TFB), the preparation method is as follows: spin-coating a chlorobenzene solution of 8 mg/ml TFB at a rotational speed of 3000 r/min to form a film, and then bake at 110° C. for 10 min. The material of the quantum dot light-emitting layer is blue quantum dots with a CdSe/ZnS core-shell structure. Bake at 100°C for 5 minutes. The material of the electron transport layer is ZnMgO nanoparticle thin film, and the preparation method is as follows: spin coating the ethanol solution of 20mg/ml ZnMgO nanoparticle at 2500r/min to form a film, and then bake at 100°C for 10min.

Compared with the fluorescent blue OLED of Example 1, the blue QLED used in the second light-emitting unit of Example 5 further improves the color gamut of the light-emitting device.

Example 6

The only difference between this embodiment and Embodiment 5 is that the third electrode is an Ag nanowire, which is fabricated by spin coating.

Compared with the bottom-emitting device of Example 5, Example 6 is a transparent light-emitting device, which can be applied to a transparent display.

Example 7

The difference between this embodiment and Embodiment 5 is only that the quantum dot light emitting layer of the first light emitting unit is a blue quantum dot film, and the quantum dot light emitting layer of the second light emitting unit is a red and green mixed quantum dot film.

Among them, the quantum dot preparation method of the first light-emitting unit is as follows: spin-coating the n-octane solution of blue quantum dots with 10 mg/mL CdSe/ZnS core-shell structure at a speed of 3000 r/min to form a film, and then bake at 100 °C 5min. The preparation method of the quantum dots of the second light-emitting unit is as follows: the n-octane solutions of 10 mg/mL CdSe/ZnS core-shell structure green quantum dots and 10 mg/mL CdSe/ZnS core-shell structure red quantum dots are configured in different volume ratios A mixed solution of red quantum dots and green quantum dots was formed, spin-coated at a speed of 3000 r/min to form a film, and then baked at 100 °C for 5 min.

Compared with the first light-emitting unit is the color changing unit and the second light-emitting unit is the color-fixing unit in the embodiment 5, the first light-emitting unit is the color-fixing unit and the second light-emitting unit is the color changing unit in the embodiment 7, the light-emitting device can also be realized. The luminous color is fully adjustable to obtain high-efficiency white light emission.

This embodiment also provides a display device, including the light-emitting device described in the above-mentioned embodiments, the display device can realize high-resolution and large-area display, and the light-emitting color can be adjusted in full color for full-color display; High-efficiency white light emission for white light illumination.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are relatively specific and detailed, but should not be construed as a limitation on the scope of the patent of the present application. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims (14)

1. A light-emitting device, characterized in that, comprising: base; A first electrode, a first light-emitting unit, a second electrode, a second light-emitting unit and a third electrode are sequentially stacked on the substrate; wherein: the second electrode is a transparent conductive electrode; One of the first light-emitting unit and the second light-emitting unit is a color changing unit, and one of the first light-emitting unit and the second light-emitting unit is a color fixing unit, and the color changing unit includes a first light-emitting unit. A quantum dot light-emitting layer, the light-emitting color of the first quantum dot light-emitting layer changes with the change of the driving voltage parameter. 2 . The light-emitting device according to claim 1 , wherein the first quantum dot light-emitting layer comprises a red quantum dot light-emitting layer and a green quantum dot light-emitting layer arranged in layers; or The material of the first quantum dot light-emitting layer includes a mixed light-emitting material of red quantum dots and green quantum dots. 3. The light-emitting device according to claim 1, wherein the first light-emitting unit is the color changing unit, and the color changing unit further comprises: a first hole injection layer, stacked on the side of the first electrode away from the substrate; The first hole transport layer is stacked on the side of the first hole injection layer away from the substrate, and the first quantum dot light-emitting layer is stacked on the side of the first hole transport layer away from the substrate. one side; The first electron transport layer is stacked on the side of the first quantum dot light-emitting layer away from the substrate. 4. The light-emitting device according to claim 1, wherein the color fixing unit comprises a second quantum dot light-emitting layer or an organic light-emitting layer. 5 . The light-emitting device according to claim 4 , wherein the material of the second quantum dot light-emitting layer comprises a blue quantum dot light-emitting material, and the material of the organic light-emitting layer comprises a blue organic light-emitting material. 6 . 6. The light-emitting device according to claim 4, wherein the color fixing unit further comprises: A second hole injection layer, a second hole transport layer, a second electron transport layer, and an electron injection layer; wherein: The second hole injection layer and the second hole transport layer are sequentially stacked and arranged on the side of the second electrode away from the substrate; The second quantum dot light-emitting layer or the organic light-emitting layer is stacked on the side of the second hole transport layer away from the substrate; The second electron transport layer and the electron injection layer are sequentially stacked and disposed on the side of the second quantum dot light-emitting layer or the organic light-emitting layer away from the substrate. 7 . The light-emitting device according to claim 1 , wherein the material of the second electrode comprises a transparent conductive oxide; and/or the thickness of the second electrode is 50 nm-120 nm. 8 . 8 . The light-emitting device according to claim 1 , wherein at least one of the first electrode and the third electrode is a transparent electrode. 9 . 9 . The light-emitting device according to claim 8 , wherein the material of the transparent electrode comprises one of transparent conductive oxide and conductive metal. 10 . 10. The light-emitting device according to any one of claims 1-6, wherein the light-emitting device further comprises: A sputtering buffer layer is provided between the first light-emitting unit and the second electrode. 11. The light emitting device of claim 10, wherein the sputtering buffer layer comprises one or a stack of a metal layer and a ZnO-based nanoparticle layer. 12 . The light-emitting device according to claim 11 , wherein the metal layer has a thickness of 1 nm-5 nm, and the ZnO-based nanoparticle layer has a thickness of 40 nm-100 nm. 13 . 13. A method for adjusting light-emitting color, for adjusting the light-emitting color of the light-emitting device according to any one of claims 1-12, characterized in that, comprising: Connect the first electrode and the third electrode to the first end of the AC power supply after short-circuiting, and connect the second electrode to the second end of the AC power supply; Adjust the driving voltage parameter of the AC power source to adjust the light-emitting color of the light-emitting device; or connecting the first electrode with the first end of the DC power supply, and connecting the third electrode with the second end of the DC power supply; The driving voltage parameter of the DC power supply is adjusted to adjust the light-emitting color of the light-emitting device. 14. A display device, characterized by comprising the light-emitting device according to any one of claims 1-12.

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