CN113937232A - A kind of quantum dot light-emitting diode and its preparation method and application - Google Patents
A kind of quantum dot light-emitting diode and its preparation method and application Download PDFInfo
- Publication number
- CN113937232A CN113937232A CN202111133799.8A CN202111133799A CN113937232A CN 113937232 A CN113937232 A CN 113937232A CN 202111133799 A CN202111133799 A CN 202111133799A CN 113937232 A CN113937232 A CN 113937232A
- Authority
- CN
- China
- Prior art keywords
- light
- quantum dot
- emitting
- emitting unit
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
- H10K50/805—Electrodes
- H10K50/81—Anodes
-
- 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
- H10K50/805—Electrodes
- H10K50/82—Cathodes
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/80—Constructional details
- H10K59/86—Series electrical configurations of multiple OLEDs
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Nanotechnology (AREA)
- Manufacturing & Machinery (AREA)
- Electroluminescent Light Sources (AREA)
Abstract
本发明具体公开了一种量子点发光二极管及其制备方法与应用。量子点发光二极管包括依次层叠的第一阳极、第一发光单元、阴极、第二发光单元和第二阳极；第一发光单元与第二发光单元互为镜相结构，第一发光单元与第二发光单元共用阴极；制备方法包括以下步骤：采用沉积的方法将第一阳极、第一发光单元、阴极、第二发光单元和第二阳极进行依次堆叠制得；本发明的量子点发光二极管以两个发光单元背靠背方式串联，且两个发光单元共用一个阴极，大大提高了电子和空穴的利用率，提高光电性能，具有2.2V超低启亮电压，在8V时的亮度可达86550cd m‑2，且在不同电压驱动下，其CIE色度坐标无明显变化，表现出稳定的电致发光光谱。
The invention specifically discloses a quantum dot light-emitting diode and a preparation method and application thereof. The quantum dot light-emitting diode includes a first anode, a first light-emitting unit, a cathode, a second light-emitting unit and a second anode that are stacked in sequence; the first light-emitting unit and the second light-emitting unit are mutually mirror-phase structures, and the first light-emitting unit and the second The light-emitting unit shares a cathode; the preparation method includes the following steps: using a deposition method to sequentially stack a first anode, a first light-emitting unit, a cathode, a second light-emitting unit and a second anode; the quantum dot light-emitting diode of the present invention is made of two The two light-emitting units are connected in series in a back-to-back manner, and the two light-emitting units share a cathode, which greatly improves the utilization rate of electrons and holes, and improves the photoelectric performance . 2 , and its CIE chromaticity coordinates did not change significantly under different voltage driving, showing a stable electroluminescence spectrum.
Description
Technical Field
The invention belongs to the technical field of light emitting diodes, and particularly relates to a quantum dot light emitting diode and a preparation method and application thereof.
Background
Quantum Dot Light-Emitting Diodes (QLEDs) have characteristics of adjustable emission color, narrow half-peak width, low solution processing cost, high efficiency, good stability, and the like, and thus have attracted more and more attention in recent years, and are considered as one of the best candidates for next-generation display and illumination. At present, the optimization design research of materials and device structures focuses on monochromatic light emission, and the polychromatic light emission is mainly realized by three methods, but a series of problems of unstable emission spectrum, high starting voltage, low brightness, short service life, complex structure of a series device and the like exist, and the method specifically comprises the following steps:
(1) a single quantum dot light-emitting layer is prepared by mixing a plurality of colors of red, green and blue (or more colors) according to different proportions, so that the multicolor light-emitting is realized. In 2015, Heesun Yang and his colleagues reported that white devices prepared using mixed quantum dots of red, green and blue had an external quantum efficiency of 10.9% at peak and a luminance of 23352cd m at 10V-2Excellent performance (K.Lee, C.Han, H.Kang, H.Ko, C.Lee, J.Lee, N.Myoung, S.Yim, H.Yang.Highly Effect, Color-Reproducible Full-Color electrolyte Devices Based on Red/Green/Blue Quantum Dot-Mixed multilayered layer, ACS Nano 2015,9, 10941-. In this case, however, after the red, green and blue quantum dots are mixed, forster resonance energy transfer (FRET,
resonantenergy transfer) leading to severe exciton quenching and unstable electroluminescence spectra of the quantum dot emissive layer.
(2) The red, green and blue light emitting layers are designed to be continuously stacked, simultaneously, a buffer layer series device structure is introduced among the red, green and blue light emitting layers, and the composite color light emitting is realized by changing the external voltage. The addition of the buffer layer can relieve the Forster Resonance Energy Transfer (FRET) between the quantum dots and avoid the phenomenon of the FRETThe bottom layer film is prevented from being washed by the solvent of the upper layer. In 2018, Heesun Yang and his colleagues reported that inserting a zinc oxide (ZnO) buffer layer between red, green and blue light emitting layers produced an external quantum efficiency with a peak of 6.8% and a maximum luminance of 16241cd m-2The white light quantum dot light emitting diode (K.Lee, C.Han, E.Jang, J.Jo, S.Hong, J.Hwang, E.Choi, J.Hwanga, H Yang.full-color-visible light-emitting diode based on light-processing quantum dot layer mounting, Nanoscale,2018,10, 6300-. However, the adjustable color range of the series device structure is narrow, the different light emitting layers still have great influence, and the existence of the buffer layer also causes difficulty in injecting electrons and holes, so that the problems of low brightness, high starting voltage and the like of the device are caused.
(3) A charge generation layer is designed, and independent monochromatic devices are connected in series to achieve multicolor light emission. The single-color devices are independent, so that the influence among the single-color devices is small, and efficient and stable multicolor luminescence can be provided. In 2020 Jang-Kun Song and his colleagues reported a charge generation layer PVK/PEDOT: PSS/PVK, where PVK is poly (9-vinylcarbazole), PEDOT: PSS is poly 3, 4-ethylenedioxythiophene: polystyrene sulfonate, to finally realize the preparation of a multicolor quantum dot light emitting diode (S.Song, S.park, T.Bae, K.Jung, W.park, Y.Kim, Q.Yan, S.Kim, J.Song.all-source-processed color-tunable array quantum-dot-light-emitting diode 170by AC signal, Nanoscale,2020,12, 17020-. However, the current method has the defects of difficult design of the charge generation layer with the key structure and high requirement on the preparation process, so the method has great limitation. In addition, the quantum dot light emitting diode with the structure also has the problems of too high lighting voltage and lower brightness.
Therefore, there is a need to develop a quantum dot light emitting diode with stable emission spectrum, high turn-on voltage, high brightness, long service life and simple device series structure.
Disclosure of Invention
The invention provides a quantum dot light-emitting diode, a preparation method and an application thereof, which are used for solving one or more technical problems in the prior art and at least providing a beneficial selection or creation condition.
To overcome the above technical problems, a first aspect of the present invention provides a quantum dot light emitting diode.
The quantum dot light-emitting diode comprises a first anode, a first light-emitting unit, a cathode, a second light-emitting unit and a second anode which are sequentially stacked;
the first light-emitting unit and the second light-emitting unit are in a mirror structure, and the first light-emitting unit and the second light-emitting unit share the cathode.
According to the invention, the first light-emitting unit and the second light-emitting unit which are in a mirror phase structure are connected in series in a back-to-back manner through the cathode, so that the compound-color light emission is realized. The cathode is used as an intermediate electrode and is shared by the first light-emitting unit and the second light-emitting unit, electrons are injected into the first light-emitting unit and the second light-emitting unit, and the injected electrons are respectively transported to the first light-emitting unit and the second light-emitting unit which are in a mirror structure with each other in two opposite directions. Meanwhile, the first and second anodes inject holes into the first and second light emitting units, and electrons and holes are simultaneously injected into the first and second light emitting units, thereby realizing multicolor light emission.
Compared with the prior tandem type light emitting diode, the invention can not comprise a charge generation layer with a complex structure because: the charge generation layer is a structure formed by an n-type material and a p-type material, is used for connecting different light-emitting units and has the functions of generating carriers and transferring the carriers to the next light-emitting unit, so that the reasonable charge generation layer is very difficult to design, the structure is very complex, and great limitation exists. The quantum dot light-emitting diode can connect different light-emitting units through a simple middle electrode, and easily injects electrons into different light-emitting units, so that the structure is simple and effective, and a complex charge generation layer is omitted.
As a further improvement of the above aspect, the first anode and the second anode are identical in shape and overlap each other in longitudinal position.
In particular, in order to avoid using an extra electrode to connect the first anode and the second anode, the first anode and the second anode of the invention have the same shape, and the longitudinal positions of the two anodes are overlapped with each other. The middle cathode is connected with the two light-emitting units at the same time, so that the cathode can be used as the cathode of the two light-emitting units at the same time, and electrons can be injected into the two light-emitting units at the same time only by connecting one cathode. Compared with the existing tandem type light-emitting diode which needs three or more electrodes, the invention only needs to be connected with two driving power supplies of the anode and the cathode, saves the production cost, simplifies the product structure and is beneficial to industrialized application.
Preferably, the first anode and the second anode respectively include four L-shaped electrode plates, and the four L-shaped electrode plates are symmetrically disposed on the upper surface of the substrate or the second light emitting unit, respectively. Wherein: the L-shaped electrode plates comprise transverse electrode plates and vertical electrode plates, the transverse electrode plates are perpendicular to the vertical electrode plates, and the transverse electrode plates of adjacent L-shaped electrode plates are parallel to each other or the vertical electrode plates are parallel to each other.
As a further improvement of the above aspect, the first light-emitting unit includes a first hole injection layer, a first hole transport layer, a first quantum dot light-emitting layer, and a first electron transport layer, which are stacked in this order;
the second light-emitting unit comprises a second electron transport layer, a second quantum dot light-emitting layer, a second hole transport layer and a second hole injection layer which are sequentially stacked;
the cathode is disposed between the first electron transport layer and the second electron transport layer.
Specifically, the first light-emitting unit and the second light-emitting unit are arranged in a back-to-back mode in a mirror-phase manner, the cathode is arranged between the first electron transmission layer and the second electron transmission layer, electrons of the cathode can be reversely transported in two directions, the performance of the light-emitting device is favorably improved, and when the electrons and the holes move to the quantum dot light-emitting layers of the two light-emitting units, excitons can be formed to emit light through radiative recombination. The reason for this is that: in the quantum dot light-emitting diode, the capability of injecting electrons and holes into the light-emitting layer is different, generally, the electrons are easier to inject into the light-emitting layer than the holes, so that the light-emitting layer of the quantum dot light-emitting diode has more electrons, less holes and unbalanced injection of electron holes, and Auger recombination is generated to reduce the performance of the device. The electrons injected from the middle cathode are simultaneously injected into the two light-emitting units, so that the electrons injected into each light-emitting unit are relatively reduced, the injection of the electrons and holes is more balanced, the electrons injected into the two light-emitting units are better utilized, the utilization rate of the electrons is greatly improved, and the performance of the device is further improved.
As a further improvement of the above scheme, the materials of the first hole injection layer and the second hole injection layer are respectively selected from one or more of poly 3, 4-ethylenedioxythiophene and polystyrene sulfonate, NiO, CuO, CuS, MoO3, 2,3,6,7,10, 11-hexacyano-1, 4,5,8,9, 12-Hexaazatriphenylene (HATCN);
the materials of the first hole transport layer and the second hole transport layer are respectively selected from 9, 9-dioctyl fluorene-CO-N- (4-butyl phenyl) diphenylamine, poly (9-vinyl carbazole) (PVK) and poly [ bis (4-phenyl) (4-butyl phenyl) amine](Poly-TPD), N '-diphenyl-N, N' - (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine (NPB), 4 '-tris (carbazol-9-yl) triphenylamine (TCTA), 4' -cyclohexylbis [ N, N-bis (4-methylphenyl) aniline)](TAPC), 4' -bis (9-Carbazole) Biphenyl (CBP), MoO3、WoO3、NiO、CuO、V2O5And one or more of CuS;
the materials of the first electron transmission layer and the second electron transmission layer are selected from ZnO, ZnMgO and TiO28-hydroxyquinoline aluminum (Alq3), 8-hydroxyquinoline-lithium (Liq), 1,3, 5-tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBi), bromocresol purple sodium salt (BCP), 4, 7-diphenyl-1, 10-phenanthroline (BPhen), 3- (biphenyl-4-yl) -5- (4-tert-butylphenyl) -4-phenyl-4H-1, 2, 4-Triazole (TAZ), 3'- [5' - [3- (3-pyridyl) phenyl ] Triazole (TAZ)][1,1':3', 1' -terphenyl]-3,3 "-diyl]One or more of bipyridine (TmPyPB), etc.;
preferably, the materials of the first quantum dot light-emitting layer and the second quantum dot light-emitting layer are selected from core-shell quantum dots or alloy quantum dots formed by one or more of II-VI compounds, II-V compounds, IV-VI compounds, I-III-VI compounds, I-II-IV-VI compounds and the like.
Preferably, the cathode, the first anode and the second anode are made of one or more materials selected from Indium Tin Oxide (ITO), Al, Ag and Au.
As a further improvement of the scheme, the thickness of the cathode is 1-200 nm.
Preferably, the thickness of the first anode and the second anode are both 100-200 nm.
Preferably, the thickness of each of the first quantum light emitting layer and the second quantum light emitting layer is 10-15 nm.
Preferably, the first hole injection layer and the second hole injection layer each have a thickness of 30 to 40 nm.
Preferably, the thickness of each of the first hole transport layer and the second hole transport layer is 30 to 40 nm.
Preferably, the thickness of each of the first electron transport layer and the second electron transport layer is 20 to 50 nm.
As a further improvement of the above aspect, the first light emitting unit and the second light emitting unit emit light of the same color or light of different colors, respectively.
Preferably, the first light emitting unit emits red light, and the second light emitting unit emits red light.
Preferably, the first light emitting unit emits blue light, and the second light emitting unit emits green light.
Preferably, the first light emitting unit emits blue light, and the second light emitting unit emits red light.
Preferably, the first light emitting unit emits green light, and the second light emitting unit emits red light.
Preferably, the first quantum dot light emitting layer is made of a green light quantum dot and blue light quantum dot mixed material, the second quantum dot light emitting layer is made of a red light quantum dot material, and the manufactured quantum dot light emitting diode emits white light.
As a further improvement of the above scheme, the quantum dot light emitting diode further includes a substrate, and the first anode is disposed on the substrate.
The second aspect of the invention provides a preparation method of a quantum dot light-emitting diode.
Specifically, the preparation method of the quantum dot light-emitting diode comprises the following steps: and stacking the first anode, the first light-emitting unit, the cathode, the second light-emitting unit and the second anode in sequence by adopting a deposition method to obtain the quantum dot light-emitting diode.
Preferably, the deposition method includes any one of a magnetron sputtering method, a solution method, and a vacuum evaporation method.
As a further improvement of the scheme, raw materials for preparing the first light-emitting unit and the second light-emitting unit respectively comprise light-emitting quantum dots, and the concentration of the light-emitting quantum dots is 5-15 mg/mL.
Preferably, the preparation method of the quantum dot light emitting diode comprises the following steps:
(1) first anode cleaning: cleaning a first anode (ITO conductive glass) for 15-30min in an ultrasonic cleaning machine at 0-100 ℃ by using a mixed solution of deionized water and a glass cleaning solution, cleaning the ITO conductive glass for 10-30min in the ultrasonic cleaning machine at 0-100 ℃ by using the deionized water, and repeating for 3 times;
(2) preparing a first hole injection layer: after the ITO conductive glass cleaned in the step (1) is subjected to ultraviolet treatment for 30-60min, 100-200 mu L cavity injection material is taken to be coated on the ITO conductive glass in a rotating mode at the rotating speed of 1000-5000r/min for 40-60s, the obtained object after the coating in a rotating mode is annealed for 15-50min in the air at the annealing temperature of 100-200 ℃, the obtained object after the annealing is transferred into a glove box, and the subsequent operations are all completed in the glove box;
(3) preparing a first hole transport layer: coating 40-100 mu L of hole transport material on the substance obtained in the step (2) in a rotating mode at the rotating speed of 1000-5000r/min for 40-60s, and annealing the substance obtained by the spin coating in a nitrogen environment for 10-20min at the annealing temperature of 100-150 ℃;
(4) preparing a first quantum dot light-emitting layer: spin-coating 20-50 mu L of green light and blue light quantum dot mixed solution on the substance obtained in the step (3) at the rotation speed of 1000-5000r/min for 40-60s, and annealing the spin-coated substance in a nitrogen environment for 5-15min at the annealing temperature of 50-100 ℃;
(5) preparing a first electron transport layer: spin-coating 40-100 μ L of electron transport material on the material obtained in step (4) at a rotation speed of 1000-;
(6) preparing a cathode: transferring the product obtained in the step (5) to an evaporation chamber, vacuumizing and keeping the pressure below 5 multiplied by 10 < -4 > Pa for evaporation, and continuously adjusting the evaporation temperature to keep the evaporation rate of the material at
Preparing a cathode;
(7) preparing a second electron transport layer: spin-coating 10-100 μ L of electron transport material on the material obtained in step (6) at a rotation speed of 1000-;
(8) preparing a second quantum dot light-emitting layer: spin-coating 20-50 mu L of red light quantum dot mixed solution on the substance obtained in the step (7) at the rotation speed of 1000-;
(9) preparing a second hole transport layer: transferring the product obtained in the step (8) to an evaporation bin, vacuumizing and keeping the pressure below 5 multiplied by 10 < -4 > Pa for evaporation, and continuously adjusting the evaporation temperature and keeping the evaporation rate of the material at
Preparing a second hole transport layer;
(10) preparing a second hole injection layer: continuously evaporating the hole injection material on the basis of the step (9), wherein the evaporation bin gate is not required to be opened, and the evaporation temperature is continuously adjusted to keep the material evaporatedAt a rate of
Preparing a second hole injection layer;
(11) preparing a second anode: continuously evaporating a second anode material on the basis of the step (10), wherein an evaporation bin gate does not need to be opened, the evaporation temperature is continuously adjusted, and the evaporation rate of the material is kept at
And finally, preparing a white light emitting quantum dot light emitting diode.
A third aspect of the invention provides the use of a quantum dot light emitting diode.
Concretely, a light emitting device comprises the quantum dot light emitting diode.
Compared with the prior art, the technical scheme of the invention at least has the following technical effects or advantages:
(1) the quantum dot light-emitting diode realizes different light color emission by connecting two independent light-emitting units (the first light-emitting unit and the second light-emitting unit) in series in a back-to-back mode which mutually serves as a mirror phase, and the service life of the quantum dot light-emitting diode is obviously prolonged compared with that of a single light-emitting unit.
(2) The quantum dot light-emitting diode adopts the two light-emitting units to share one cathode, the cathode injects electrons into the two light-emitting units (the first light-emitting unit and the second light-emitting unit) at the same time, a complex charge generation layer does not need to be designed, the structure is simpler, and the preparation is easier.
(3) The quantum dot light-emitting diode adopts the cathode shared in the middle and the first anode and the second anode which are same in shape, only needs two driving electrodes, namely a positive driving electrode and a negative driving electrode, and needs more than three driving electrodes compared with the traditional serial light-emitting diode, so that the production cost is saved, and the industrial application is facilitated.
(4) Quantum of the inventionThe point light emitting diode is connected in series in a back-to-back mode that two light emitting units are mutually mirror-phase, and the two light emitting units share one cathode, so that the utilization rate of electrons and holes is greatly improved, the photoelectric property of the device is more excellent, the device has 2.2V ultra-low starting voltage, and the brightness can reach 86550cd m at 8V-2And under the drive of different voltages, the CIE chromaticity coordinate of the electroluminescent material has no obvious change, and the electroluminescent material shows stable electroluminescent spectrum.
Drawings
FIG. 1 is a schematic diagram of a quantum single light emitting diode structure according to the present invention;
FIG. 2 is a working schematic diagram of a quantum single light emitting diode of the present invention;
FIG. 3 shows the electroluminescence spectra of the quantum dot light emitting diodes prepared in example 1 and comparative examples 1 to 2 of the present invention;
FIG. 4 is a graph comparing External Quantum Efficiency (EQE) -current density performance of quantum dot light emitting diodes prepared in example 1 and comparative examples 1-2 of the present invention;
FIG. 5 is a graph comparing current density-voltage-luminance performance of quantum dot light emitting diodes prepared in example 1 and comparative examples 1 to 2 according to the present invention;
FIG. 6 is a graph showing a comparison of the operating life of quantum dot light emitting diodes prepared in example 1 and comparative examples 1 to 2 according to the present invention;
FIG. 7 shows the electroluminescence spectra of 3-8V of the quantum dot light-emitting diode prepared in example 2 of the present invention;
FIG. 8 shows the electroluminescence spectra of the quantum dot light-emitting diode prepared in example 3 of the present invention at 4-9V;
FIG. 9 shows the electroluminescence spectra of 4-8V of the quantum dot light-emitting diode prepared in example 4 of the present invention;
FIG. 10 is a graph comparing the External Quantum Efficiency (EQE) -current density performance of the quantum dot light emitting diodes prepared in examples 2-4 of the present invention;
fig. 11 is a graph comparing current density-voltage-luminance performance of quantum dot light emitting diodes prepared in examples 2 to 4 of the present invention.
Detailed Description
The present invention is described in detail below by way of examples to facilitate understanding of the present invention by those skilled in the art, and it is to be specifically noted that the examples are provided only for the purpose of further illustrating the present invention and are not to be construed as limiting the scope of the present invention.
It is noted that, in the present disclosure, relational terms such as "first" and "second," and the like, are used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities.
As shown in fig. 1, a quantum dot light emitting diode of the present invention includes a first anode 100, a first light emitting unit 200, a cathode 300, a second light emitting unit 400, and a second anode 500, which are sequentially stacked, wherein: the first light emitting unit 200 and the second light emitting unit 400 are mirror-structured, and the first light emitting unit 200 and the second light emitting unit 400 share the cathode 300.
As a preferred embodiment of the present invention, the first light emitting unit 200 includes a first hole injection layer 201, a first hole transport layer 202, a first quantum dot light emitting layer 203, and a first electron transport layer 204, which are sequentially stacked; the second light emitting unit 400 includes a second electron transport layer 404, a second quantum dot light emitting layer 403, a second hole transport layer 402, and a second hole injection layer 401, which are sequentially stacked; the cathode 300 is disposed between the first electron transport layer 204 and the second electron transport layer 404.
In a preferred embodiment of the present invention, the first anode 100 and the second anode 500 have the same shape and are overlapped with each other in the longitudinal direction.
As a preferred embodiment of the present invention, the quantum dot light emitting diode of the present invention further includes a substrate 600, and the first anode 100 is disposed on the substrate 600.
As a preferred embodiment of the present invention, the first anode 100 includes four L-shaped electrode plates 101, and the four L-shaped electrode plates 101 are symmetrically disposed on the upper surface of the substrate 600. Wherein: the L-shaped electrode plate 101 comprises a transverse electrode plate 1011 and a vertical electrode plate 1012, the transverse electrode plate 1011 and the vertical electrode plate 1012 are perpendicular to each other, and the transverse electrode plate 1011 of the adjacent L-shaped electrode plate 101 is parallel to each other or the vertical electrode plate 1012 is parallel to each other.
The second anode 500 includes four L-shaped electrode plates 501, and the four L-shaped electrode plates 501 are respectively and symmetrically disposed on the upper surface of the second hole injection layer 401. Wherein: the L-shaped electrode plates 501 include transverse electrode plates 5011 and vertical electrode plates 5012, the transverse electrode plates 5011 and the vertical electrode plates 5012 are perpendicular to each other, and the transverse electrode plates 5011 of adjacent L-shaped electrode plates 501 are parallel to each other or the vertical electrode plates 5012 are parallel to each other.
As shown in fig. 2, in the figure: ETL denotes electron transport, HTL denotes hole transport, and HIL denotes hole injection. The cathode 300 is used as a middle electrode, and the first light-emitting unit 200 and the second light-emitting unit 400 which are in a mirror phase structure are connected in a back-to-back manner, so that the composite color light emission is realized. Wherein: the first light-emitting unit 200 is of a forward structure, the second light-emitting unit 400 is of an inverted structure, the first light-emitting unit 200 and the second light-emitting unit 400 share one middle electrode, namely the cathode 300, electrons are injected through the cathode 300, and the injected electrons are respectively transported to the first quantum dot light-emitting layer 203 and the second quantum dot light-emitting layer 403 through the first electron transport layer 204 and the first electron transport layer 404 in two opposite directions; meanwhile, the first anode 100 and the second anode 500 inject holes into the first quantum dot light emitting layer 203 and the second quantum dot light emitting layer 403 through the first hole injection layer 201, the first hole transport layer 202 and the second hole injection layer 401, and the second hole transport layer 402, respectively; when electrons and holes are simultaneously injected into the first quantum dot light emitting layer 203 and the second quantum dot light emitting layer 403, excitons are synchronously generated, and finally, double color light emission is realized.
Meanwhile, in order to avoid the use of an additional electrode to connect the first and second light emitting cells 200 and 400, the first and second anodes 100 and 500 adopt the same shape and the longitudinal positions overlap each other. In the fabricated light emitting diode, the first anode 100 and the second anode 500, which have the same shape and are overlapped with each other at the longitudinal position, can be well overlapped, so that the holes can simultaneously enter the first light emitting unit 200 and the second light emitting unit 400 only by connecting one anode. The middle cathode 300 is connected to the first light emitting unit 200 and the second light emitting unit 400 at the same time, so that it can be used as the cathode of the first light emitting unit 200 and the second light emitting unit 400 at the same time, and thus it is only necessary to connect one cathode to inject electrons into the first light emitting unit 200 and the second light emitting unit 400 at the same time. Compared with the existing tandem type light-emitting diode which needs three or more electrodes, the invention only needs to be connected with two driving power supplies of the anode and the cathode, saves the production cost, simplifies the product structure and is beneficial to industrialized application.
Therefore, the serial quantum dot light-emitting diode has more advantages compared with the prior serial quantum dot light-emitting diode. Firstly, a charge generation layer with a complex structure is not required to be designed, so that the structure of the device can be simplified; secondly, electrons injected by the middle electrode (cathode 300) can be transported to two opposite directions, so that the utilization rate of the electrons is greatly improved, and the performance of the device is further improved; thirdly, the quantum dot light-emitting diode has good photoelectric efficiency, and the performance of the quantum dot light-emitting diode is greatly improved.
Example 1
A quantum dot light-emitting diode comprises a first anode, a first hole injection layer, a first hole transport layer, a first quantum dot light-emitting layer, a first electron transport layer, a cathode, a second electron transport layer, a second quantum dot light-emitting layer, a second hole transport layer, a second hole injection layer and a second anode which are sequentially stacked.
Wherein: the first anode is made of indium tin oxide and has the thickness of 120 nm;
the first hole injection layer is made of poly (3, 4-ethylenedioxythiophene) and polystyrene sulfonate and has the thickness of 40 nm;
the material of the first hole transport layer is poly (9, 9-dioctylfluorene) -CO-N- (4-butylphenyl) diphenylamine (TFB) with a thickness of 30 nm;
the first quantum dot light-emitting layer is made of CdZnSe/CdZnS/ZnS red light quantum dots with core-shell structures, and the thickness of the first quantum dot light-emitting layer is 20 nm;
the material of the first electron transport layer is magnesium-doped zinc oxide (ZnMgO), and the thickness is 40 nm;
the cathode is made of Al, and the thickness of the cathode is 100 nm;
the second electron transport layer is made of magnesium-doped zinc oxide (ZnMgO) and has the thickness of 40 nm;
the second quantum dot light-emitting layer is made of CdZnSe/CdZnS/ZnS red light quantum dots with core-shell structures, and the thickness of the second quantum dot light-emitting layer is 20 nm;
the material of the second hole transport layer is 4,4' -bis (9-Carbazole) Biphenyl (CBP) with the thickness of 45 nm;
the material of the second hole injection layer is molybdenum trioxide (MoO)3) The thickness is 10 nm;
the material of the second anode is Al, and the thickness is 150 nm.
A preparation method of a quantum dot light-emitting diode comprises the following steps:
(1) ITO cleaning: cleaning ITO conductive glass for 15min in a 60 ℃ ultrasonic cleaning machine by using a mixed solution of deionized water and a glass cleaning solution, cleaning the ITO conductive glass for 10min in the 60 ℃ ultrasonic cleaning machine by using the deionized water, and repeating the steps for 3 times;
(2) preparing a first hole injection layer PEDOT PSS: and (2) after the ITO cleaned in the step (1) is subjected to ultraviolet treatment for 30min, 150 mu L of PEDOT (PSS) material is sucked by a liquid transfer gun and is coated on ITO conductive glass in a spinning mode, the rotating speed is 3000r/min, the time is 40s, and the obtained product after the spinning mode is placed on a hot bench at the temperature of 150 ℃ in the air and is annealed for 30min, so that the first hole injection layer PEDOT (PSS) is obtained.
(3) Transferring the product obtained in the step (2) to a glove box, and subsequently operating in the nitrogen atmosphere of the glove box;
(4) preparation of the first hole transport layer TFB: absorbing 50 mu L of TFB material with the concentration of 8mg/mL by a liquid transfer gun, spin-coating the TFB material on the product obtained in the step (3), rotating at 3000r/min for 40s, and placing the spin-coated product on a heating table at 120 ℃ for annealing for 15min to obtain a first hole transport layer TFB;
(5) preparation of a first quantum dot light-emitting layer (red): absorbing 30 mu L of CdZnSe/CdZnS/ZnS core-shell structure red light quantum dot solution with the concentration of 10mg/mL by a liquid-moving gun, spin-coating the solution on the obtained product in the step (5), rotating at 3000r/min for 40s, and placing the spin-coated obtained product on a heating table at 90 ℃ for annealing for 7min to obtain a first quantum dot light-emitting layer;
(6) preparing a first electron transport layer ZnMgO: absorbing 60 mu L of ZnMgO solution with the concentration of 20mg/mL by a liquid transfer gun, spin-coating the ZnMgO solution on the product obtained in the step (5), rotating at 3000r/min for 40s, and placing the spin-coated product on a 60 ℃ hot bench for annealing for 10min to obtain a first electron transport layer ZnMgO;
(7) preparing an intermediate electrode Al: transferring the product obtained in the step (6) to an evaporation bin and vacuumizing to 5 multiplied by 10-4Evaporating aluminum electrode under Pa, and continuously adjusting evaporation temperature to maintain evaporation rate of Al material at
Steaming to obtain an Al electrode with the film thickness of 100nm, thus obtaining an intermediate electrode Al;
(8) preparing a second electron transport layer ZnMgO: absorbing 30 mu L of ZnMgO solution with the concentration of 20mg/mL by a liquid transfer gun, spin-coating the ZnMgO solution on the product obtained in the step (7), rotating at 3000r/min for 40s, and placing the spin-coated product on a hot bench at 60 ℃ for annealing for 10min to obtain a second electron transport layer ZnMgO;
(9) preparation of a second quantum dot light-emitting layer (red): absorbing 30 mu L of CdZnSe/CdZnS/ZnS core-shell structure red light quantum dot solution with the concentration of 10mg/mL by a liquid-moving gun, spin-coating the solution on the obtained substance in the step (8) at the rotating speed of 3000r/min for 40s, and placing the spin-coated obtained substance on a hot bench at the temperature of 60 ℃ for annealing for 10min to obtain a second quantum dot light-emitting layer;
(10) preparing a second hole transport layer CBP: transferring the product obtained in the step (9) to an evaporation bin and vacuumizing to 5 multiplied by 10- 4Performing vapor deposition of CBP material below Pa, and continuously adjusting vapor deposition temperature to maintain the evaporation rate of CBP material at
Steaming to obtain a CBP film with the thickness of 45nm, thus obtaining a second hole transport layer CBP;
(11) preparation of second hole injection layer MoO3: continuing MoO on the basis of the product obtained in the step (10)3Material evaporation, during which evaporation must not be openedA plating bin gate for continuously adjusting the evaporation temperature to keep the evaporation rate of the MoO3 material at
Steaming to obtain MoO3 with the film thickness of 10nm, thus obtaining a second hole injection layer MoO 3;
(12) preparing a top layer anode Al: continuing to perform Al electrode evaporation on the basis of the product obtained in the step (11), wherein the evaporation bin gate is not opened, and the evaporation rate of the Al material is kept at the same value by continuously adjusting the evaporation temperature
And (3) steaming to obtain an Al electrode film with the thickness of 150nm, thus obtaining the anode Al on the top layer, and finally completely preparing the pure red emitting monochromatic emitting back-to-back type series quantum dot light-emitting diode.
Comparative example 1
Comparative example 1 is a conventional forward monochromatic quantum dot light emitting diode, comprising an anode, a hole injection layer, a hole transport layer, a quantum dot light emitting layer, an electron transport layer and a cathode, which are sequentially stacked. Wherein:
the anode is made of Indium Tin Oxide (ITO) and has the thickness of 120 nm;
the hole injection layer is made of poly (3, 4-ethylenedioxythiophene) (polystyrene sulfonate) (PEDOT: PSS) and has a thickness of 40 nm;
the hole transport layer is made of poly (9, 9-dioctyl fluorene) -CO-N- (4-butylphenyl) diphenylamine (TFB) and has a thickness of 30 nm;
the quantum dot light-emitting layer is made of CdZnSe/CdZnS/ZnS red light quantum dots with core-shell structures, and the thickness of the quantum dot light-emitting layer is 20 nm;
the electron transport layer is made of magnesium-doped zinc oxide (ZnMgO) and has the thickness of 40 nm;
the cathode is made of Al and has a thickness of 100 nm.
The method for manufacturing the quantum dot light emitting diode of comparative example 1 is the same as the steps (1) to (7) of the method for manufacturing the quantum dot light emitting diode of example 1, and finally, a single-layer forward quantum dot light emitting diode emitting red light is manufactured.
Comparative example 2
Comparative example 2 is a conventional inverted monochromatic quantum dot light emitting diode comprising a cathode, an electron transport layer, a quantum dot light emitting layer, a hole transport layer, a hole injection layer and an anode. Wherein:
the cathode is made of Indium Tin Oxide (ITO) and has the thickness of 120 nm;
the electron transport layer is made of magnesium-doped zinc oxide (ZnMgO) and has the thickness of 40 nm;
the quantum dot light-emitting layer is made of CdZnSe/CdZnS/ZnS red light quantum dots with core-shell structures, and the thickness of the quantum dot light-emitting layer is 20 nm;
the hole transport layer is made of 4,4' -bis (9-Carbazole) Biphenyl (CBP) and has the thickness of 45 nm;
the material of the hole injection layer is molybdenum trioxide (MoO)3) The thickness is 10 nm;
the anode is made of Al and has a thickness of 150 nm.
The method for manufacturing the quantum dot light emitting diode of the comparative example 2 is the same as the steps (8) to (12) of the method for manufacturing the quantum dot light emitting diode of the example 1, and finally, the single-layer inverted quantum dot light emitting diode emitting red light is manufactured.
Example 2
The quantum dot light emitting diode of the embodiment 2 has substantially the same structure and manufacturing method as those of the quantum dot light emitting diode of the embodiment 1, except that: the first quantum dot light-emitting layer in embodiment 2 is made of a blue quantum dot with a CdZnSe/ZnSeS/ZnS core-shell structure, and has a thickness of 20 nm; the thickness of the cathode is 5nm, and finally the quantum dot light-emitting diode which emits blue light and red light in a two-color manner and is connected in series in a back-to-back manner is prepared.
Example 3
The structure and the preparation method of the quantum dot light emitting diode in the embodiment 3 are basically the same as those of the quantum dot light emitting diode in the embodiment 1, except that: the first quantum dot luminescent material of embodiment 3 is a green quantum dot of a CdZnSeS/ZnS core-shell structure, and the film thickness is 20 nm; the thickness of the cathode is 5nm, and finally the quantum dot light-emitting diode which emits green light and red light in a two-color mode and is connected in series in a back-to-back mode is prepared.
Example 4
The structure and the preparation method of the quantum dot light emitting diode in the embodiment 4 are basically the same as those of the quantum dot light emitting diode in the embodiment 1, except that: the first quantum dot luminescent material of embodiment 4 is a mixed quantum dot of a green light quantum dot of a CdZnSeS/ZnS core-shell structure and a blue light quantum dot of a CdZnSe/ZnSeS/ZnS core-shell structure, the thickness is 20nm, and the volume ratio of the green light quantum dot to the blue light quantum dot is 1:4 under the same concentration condition; the thickness of the cathode is 5nm, and finally the back-to-back type serial quantum dot light-emitting diode emitting white light is prepared.
Performance testing
1. Photoelectric performance test
The quantum dot light emitting diodes prepared in example 1, comparative example 1 and comparative example 2 were subjected to photoelectric property tests, and the results of the property tests are shown in table 1.
Table 1: photoelectric property comparison table of quantum dot light-emitting diode of example 1 and comparative examples 1-2
As shown in fig. 3, the electroluminescence spectra of the quantum dot light emitting diode prepared in example 1 of the present invention are not changed compared to the quantum dot light emitting diodes prepared in comparative examples 1 and 2, which shows that the quantum dot light emitting diode prepared in the example does not cause the change of the emission peak.
As shown in fig. 4 to 6, the quantum dot light emitting diode prepared in example 1 has External Quantum Efficiency (EQE) very close to that of the quantum dot light emitting diodes prepared in comparative examples 1 and 2, both of which are greater than 20%. However, the quantum dot light emitting diode prepared in example 1 reached 52500 cd m in luminance at 4V-2Compared with comparative example 1 and comparative example 2, the quantum dot light-emitting diode prepared by the comparative example has the brightness of 15286 cd m at 4V-2And 270cd m-2The brightness of the quantum dot light emitting diode of embodiment 1 is remarkably improved. In addition, the quantum dot light emitting diode prepared in example 1 had an initial luminance of 5000cd m-2The operating life of the luminance decay to 50% (T50) reached 297h, compared to comparative example 1 and comparative exampleRatio 2 has a two-fold improvement. It can be seen that the monochromatic emitting back-to-back series quantum dot light emitting diode of example 1 has a significant improvement in photoelectric performance.
The quantum dot light-emitting diodes prepared in examples 2 to 4 were subjected to photoelectric property tests, and the results of the property tests are shown in table 2.
Table 2: comparative table of photoelectric Properties of Quantum dot light emitting diodes of examples 2 to 4
As shown in fig. 7 to 9, the quantum dot light emitting diodes prepared in examples 2 to 4 all realized stable multicolor light emission. As shown in FIGS. 10 to 11, the white light emission of example 4, having an ultra-low on-luminance voltage of 2.2V and a luminance of 86550cd m at 8V, was achieved-2Therefore, a new idea is provided for the colorful display field in the future. The two-color quantum dot light-emitting diodes prepared in the embodiments 2 and 3 have low lighting voltage and high lighting brightness, so that the back-to-back series quantum dot light-emitting diodes of the embodiments 2 to 4 have great application prospect in the field of multi-color light emission.
2. Chromaticity coordinate
The quantum dot light emitting diodes prepared in examples 2 to 4 were subjected to the CIE (international commission on illumination) chromaticity coordinate test at different driving voltages, and the performance test results thereof are shown in table 3.
Table 3: CIE chromaticity coordinate comparison table of Quantum dot light emitting diodes of examples 2 to 4
| Voltage (V) | Example 2 | |
Example 4 |
| 3 | (0.38，0.19) | - | - |
| 4 | (0.31，0.16) | (0.38，0.59) | (0.33，0.32) |
| 5 | (0.24，0.13) | (0.33，0.64) | (0.30，0.30) |
| 6 | (0.24，0.13) | (0.34，0.63) | (0.31，0.30) |
| 7 | (0.27，0.14) | (0.37，0.61) | (0.34，0.31) |
| 8 | (0.41，0.20) | (0.40，0.57) | (0.38，0.33) |
| 9 | - | (0.46，0.52) | - |
As shown in table 3, referring to fig. 7 to 9, the quantum dot light emitting diodes prepared in examples 2 to 4 all showed stable electroluminescence spectra under different voltage driving, and particularly, the change in CIE chromaticity coordinates at high voltage was small compared to that at low voltage. Especially, the white light emitting quantum dot light emitting diode prepared in example 4 has CIE chromaticity coordinates maintained at about (0.33 ) under the driving of different voltages of 4-8V, thus representing very stable white light emission and providing a new idea for the research of white light emission.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are intended to be within the scope of the invention.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111133799.8A CN113937232A (en) | 2021-09-26 | 2021-09-26 | A kind of quantum dot light-emitting diode and its preparation method and application |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111133799.8A CN113937232A (en) | 2021-09-26 | 2021-09-26 | A kind of quantum dot light-emitting diode and its preparation method and application |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113937232A true CN113937232A (en) | 2022-01-14 |
Family
ID=79276861
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111133799.8A Pending CN113937232A (en) | 2021-09-26 | 2021-09-26 | A kind of quantum dot light-emitting diode and its preparation method and application |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113937232A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1670981A (en) * | 2004-04-21 | 2005-09-21 | 友达光电股份有限公司 | Organic light emitting diode and display panel and communication device including same |
| CN104124389A (en) * | 2013-04-28 | 2014-10-29 | 海洋王照明科技股份有限公司 | Organic light-emitting device and preparation method thereof |
| CN105304829A (en) * | 2015-11-18 | 2016-02-03 | Tcl集团股份有限公司 | Double-sided emission quantum dot light emitting diode and manufacturing method thereof |
| CN106159102A (en) * | 2016-09-28 | 2016-11-23 | Tcl集团股份有限公司 | Lamination QLED device and preparation method thereof |
| CN109671873A (en) * | 2018-12-26 | 2019-04-23 | 上海晶合光电科技有限公司 | It is a kind of can the hearth electrode of discrete control be patterned with organic electroluminescence devices and preparation method thereof |
| CN111524954A (en) * | 2020-05-08 | 2020-08-11 | 京东方科技集团股份有限公司 | Display substrate, maintenance method thereof and display device |
| CN111564564A (en) * | 2020-05-08 | 2020-08-21 | 苏州星烁纳米科技有限公司 | Electroluminescent device, preparation method thereof, display device and lighting device |
| CN114765247A (en) * | 2020-12-30 | 2022-07-19 | Tcl科技集团股份有限公司 | Quantum dot light-emitting diode, preparation method thereof, light-emitting unit and display screen |
-
2021
- 2021-09-26 CN CN202111133799.8A patent/CN113937232A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1670981A (en) * | 2004-04-21 | 2005-09-21 | 友达光电股份有限公司 | Organic light emitting diode and display panel and communication device including same |
| CN104124389A (en) * | 2013-04-28 | 2014-10-29 | 海洋王照明科技股份有限公司 | Organic light-emitting device and preparation method thereof |
| CN105304829A (en) * | 2015-11-18 | 2016-02-03 | Tcl集团股份有限公司 | Double-sided emission quantum dot light emitting diode and manufacturing method thereof |
| CN106159102A (en) * | 2016-09-28 | 2016-11-23 | Tcl集团股份有限公司 | Lamination QLED device and preparation method thereof |
| CN109671873A (en) * | 2018-12-26 | 2019-04-23 | 上海晶合光电科技有限公司 | It is a kind of can the hearth electrode of discrete control be patterned with organic electroluminescence devices and preparation method thereof |
| CN111524954A (en) * | 2020-05-08 | 2020-08-11 | 京东方科技集团股份有限公司 | Display substrate, maintenance method thereof and display device |
| CN111564564A (en) * | 2020-05-08 | 2020-08-21 | 苏州星烁纳米科技有限公司 | Electroluminescent device, preparation method thereof, display device and lighting device |
| CN114765247A (en) * | 2020-12-30 | 2022-07-19 | Tcl科技集团股份有限公司 | Quantum dot light-emitting diode, preparation method thereof, light-emitting unit and display screen |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100484353C (en) | Organic electroluminescent part | |
| KR102378408B1 (en) | Organic electroluminescent device and organic electroluminescent device | |
| CN101694849B (en) | Organic electroluminescence lamination device | |
| CN103904178A (en) | Quantum dot luminescent device | |
| CN100508244C (en) | An organic electroluminescent white light device | |
| CN100470877C (en) | A kind of organic electrophosphorescent device and its preparation method | |
| CN108963089A (en) | Quanta point electroluminescent device | |
| CN111200076A (en) | Organic light emitting device having internal light extraction structure and method of fabricating the same | |
| CN108666432A (en) | An Organic Light Emitting Diode Containing a Multilevel Organic Semiconductor Heterojunction | |
| CN113066935A (en) | A white organic electroluminescent device based on a dual exciplex | |
| CN101123298A (en) | A structure-optimized white light organic electroluminescent device | |
| CN107591491A (en) | A kind of undoped white-light emitting layer series connection organic electroluminescence device and preparation method thereof | |
| US12238951B2 (en) | Organic electroluminescent device and array substrate | |
| CN102064282B (en) | Organic electroluminescent device | |
| CN108807710A (en) | Undoped organic electroluminescence device and the preparation method of connecting with the complementary white light of doping | |
| CN108682748A (en) | A kind of series connection white light organic electroluminescent device | |
| KR102765088B1 (en) | Quantum dot-light-emitting diode and method for fabricating the same | |
| CN108288678A (en) | A kind of double blu-ray layer hydridization white light organic electroluminescent devices | |
| CN107546248A (en) | A kind of undoped white-light emitting layer series connection organic electroluminescence device | |
| CN101394696A (en) | Organic Electroluminescent Devices | |
| CN107302058A (en) | A kind of undoped white-light emitting layer series connection organic electroluminescence device | |
| CN114725293B (en) | Stable white light OLED (organic light emitting diode) with multi-luminescent layer mixed matrix structure without transmission layer | |
| CN102790180A (en) | Transmission organic electroluminescent device with color conversion layer outside | |
| CN112635686B (en) | Perovskite and organic material-based white light emitting diode and preparation method thereof | |
| CN113937232A (en) | A kind of quantum dot light-emitting diode and its preparation method and application |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |