Optoelectronic device and display apparatus

Abstract

The application discloses an optoelectronic device and a display device. The optoelectronic device comprises a stacked anode, a light-emitting functional layer and a cathode. The light-emitting functional layer comprises at least two light-emitting layers. The material of each light-emitting layer is independently selected from a first configuration quantum dot or a second configuration quantum dot. The first configuration quantum dot and the second configuration quantum dot are core-shell quantum dots. The band gap of the core of the first configuration quantum dot is between the band gap of the shell of the first configuration quantum dot. The valence band edge or the conduction band edge of the shell of the second configuration quantum dot is between the band gap of the core of the second configuration quantum dot. The optoelectronic device provided by the application has better light-emitting performance and service life. By adjusting the quantum dot collocation, the application can meet the application scenarios of various requirements.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more particularly to an optoelectronic device and display apparatus. Background Technology

[0002] Optoelectronic devices emit light by releasing energy through the recombination of electrons and holes, and are widely used in lighting, display technology, and other fields. An optoelectronic device typically consists of an anode, a cathode, and a light-emitting layer located between the anode and cathode.

[0003] Quantum dots (QDs) are nanoscale semiconductors that confine electrons and holes. By applying a specific electric field or light pressure to quantum dots, they emit light at a particular frequency. Due to their self-emission, tunable emission spectrum, pure emission color, and ease of manufacturing, quantum dots are used in light-emitting layers to improve the color quality and energy efficiency of displays.

[0004] In practical applications, more and more application scenarios with different requirements have emerged, and the currently developed light-emitting layer design is no longer able to meet the needs. Summary of the Invention

[0005] In view of this, this application provides an optoelectronic device and a display apparatus.

[0006] The embodiments of this application are implemented as follows:

[0007] In a first aspect, embodiments of this application provide an optoelectronic device, comprising a stacked anode, a light-emitting functional layer, and a cathode, wherein the light-emitting functional layer comprises at least two light-emitting layers, and the material of each light-emitting layer is independently selected from a first configuration quantum dot or a second configuration quantum dot, wherein:

[0008] The first configuration quantum dot and the second configuration quantum dot are core-shell structured quantum dots, and the band gap of the core of the first configuration quantum dot is located between the band gaps of the shell of the first configuration quantum dot, and the valence band edge or conduction band edge of the shell of the second configuration quantum dot is located between the band gaps of the core of the second configuration quantum dot.

[0009] Secondly, embodiments of this application provide a method for fabricating an optoelectronic device, comprising the following steps:

[0010] Provide the first electrode;

[0011] A multilayer film material is deposited on one side of the first electrode to form a light-emitting functional layer, the light-emitting functional layer including at least two light-emitting layers;

[0012] A second electrode is disposed on the side of the light-emitting functional layer opposite to the first electrode;

[0013] Wherein, the first electrode is selected from one of the anode and the cathode, and the second electrode is selected from the other of the anode and the cathode; the multilayer film material is independently selected from either a first configuration quantum dot or a second configuration quantum dot, wherein the first configuration quantum dot and the second configuration quantum dot are core-shell structured quantum dots, and the band gap of the core of the first configuration quantum dot is located between the band gaps of the shell of the first configuration quantum dot, and the valence band edge or conduction band edge of the shell of the second configuration quantum dot is located between the band gaps of the core of the second configuration quantum dot.

[0014] Thirdly, embodiments of this application provide a display device, including the optoelectronic device described above, or an optoelectronic device prepared by the preparation method described above.

[0015] This application proposes an optoelectronic device with superior luminescence performance and lifetime, and which can meet the needs of various application scenarios by adjusting the quantum dot combination. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an optoelectronic device provided in the first embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the structure of an optoelectronic device provided in the second embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the structure of an optoelectronic device provided in the third embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the structure of an optoelectronic device provided in the fourth embodiment of this application;

[0021] Figure 5 This is the band diagram of the first configuration quantum dot;

[0022] Figure 6 This is the band structure diagram of the first core-shell quantum dot.

[0023] Figure 7 This is the band structure diagram of a second-core-shell quantum dot;

[0024] Reference numerals: Optoelectronic device 100; Anode 10; Cathode 20; Third light-emitting layer 30; Hole transport layer 40; Hole injection layer 50; Electron transport layer 60; First light-emitting layer 71; First sub-light-emitting layer 711; Second light-emitting layer 72; Second sub-light-emitting layer 721; Third sub-light-emitting layer 31. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. In addition, in the description of this application, the term "including" means "including but not limited to". Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and conciseness and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within that range. For example, it should be assumed that the description of a range from 1 to 6 specifically discloses subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0026] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0027] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0028] In a first aspect, embodiments of this application propose an optoelectronic device 100, such as a quantum dot light-emitting diode (LED). The optoelectronic device 100 includes a stacked anode 10, a light-emitting functional layer, and a cathode 20. The light-emitting functional layer includes at least two light-emitting layers, each made of a material independently selected from a first-configuration quantum dot or a second-configuration quantum dot. The material configurations of the at least two light-emitting layers are different, wherein: the first-configuration quantum dot and the second-configuration quantum dot are core-shell structured quantum dots, and the band gap of the core of the first-configuration quantum dot is located between the band gaps of the shell of the first-configuration quantum dot, and the valence band edge or conduction band edge of the shell of the second-configuration quantum dot is located between the band gaps of the core of the second-configuration quantum dot.

[0029] As semiconductor nanocrystals, quantum dots, when their particle size is smaller than the exciton Bohr radius, confine the mean free path of electrons to a very small range, making it easy for them to form exciton pairs with holes. The wave functions of electrons and holes overlap, thus generating an exciton absorption band. The smaller the quantum dot size, the greater the probability of exciton formation and the higher the exciton concentration; this effect is called the quantum confinement effect. The quantum confinement effect of quantum dots makes their optical properties different from those of conventional semiconductor materials. Their band structure forms some exciton energy levels near the bottom of the conduction band, generating an exciton absorption band, and the recombination of excitons will produce fluorescence radiation.

[0030] Based on the relative positions of the band gap energy levels in semiconductor materials, core-shell quantum dots can be classified into three types: type I, type II, and anti-type I.

[0031] like Figure 5 As shown, type I core-shell quantum dots exhibit the following bandgap characteristics: the valence band of the core is higher than that of the shell, the conduction band of the core is lower than that of the shell, and the bandgap of the core lies within the bandgap of the shell. It can be understood that the shell of a type I core-shell quantum dot can be one or more layers, and the valence band, conduction band, and bandgap mentioned above refer to the band structure information of the entire shell. The band structure of type I core-shell quantum dots provides strong confinement for electrons and holes, confining them within the core. This increases the overlap of electron and hole wave functions, and the recombination emission region is almost entirely located within the core. In contrast, anti-type I core-shell quantum dots exhibit the opposite behavior: the bandgap of the shell is smaller than that of the core, and electrons and holes are partially or completely delocalized into the shell, resulting in weaker confinement for both electrons and holes. In this application, the first configuration quantum dot is a type I core-shell structure quantum dot. The first configuration quantum dot includes a third core and a third shell. The band gap of the third core is located between the band gaps of the third shell. Specifically, the valence band of the third core is higher than the valence band of the third shell, and the conduction band of the third core is lower than the conduction band of the third shell.

[0032] In some embodiments, the average particle size of the first configuration quantum dots is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. In this application, the average particle size of the quantum dots can be detected by transmission electron microscopy (TEM).

[0033] In type II core-shell quantum dots, the valence band edge or conduction band edge of the shell semiconductor material is located between the band gaps of the core, exhibiting a strong confinement effect on one of electrons and holes, and a weaker confinement effect on the other. When excited, electrons and holes separate into different regions of the core and shell, with little overlap in their wave functions. The quantum dot operates at a relatively low energy level, exhibiting lower luminescence efficiency and a longer lifetime. In this application, the second configuration quantum dot is a type II core-shell quantum dot. More specifically, type II core-shell quantum dots can be further divided into first core-shell quantum dots and second core-shell quantum dots: the first core-shell quantum dot exhibits a stronger confinement effect on electrons than on holes; the second core-shell quantum dot exhibits a stronger confinement effect on holes than on electrons.

[0034] Specifically, such as Figure 6 As shown, the first core-shell quantum dot is a core-shell structured quantum dot comprising a first core and a first shell, with the first shell covering the first core. The first core-shell quantum dot exhibits the following bandgap characteristics: the valence band of the first core is lower than the valence band of the first shell, and the conduction band of the first core lies within the band gap of the first shell. It can be understood that the first shell can be one or more layers; the valence band and band gap of the shell refer to the band structure characteristics of the entire shell. The band structure of the first core-shell quantum dot exhibits strong confinement of electrons but weaker confinement of holes; a large number of electrons are bound in the nucleus, while a large number of holes remain in the shell layers.

[0035] In some embodiments, the average particle size of the first core-shell quantum dot is 5 to 15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values.

[0036] like Figure 7As shown, the second core-shell quantum dot is a core-shell structured quantum dot comprising a second core and a second shell, with the second shell covering the second core. The second core-shell quantum dot exhibits the following bandgap characteristics: the conduction band of the second core is higher than the conduction band of the second shell, and the valence band of the second core lies within the band gap of the second shell. It can be understood that the second shell can be one or more layers; the valence band and band gap of the shell refer to the band structure characteristics of the entire shell. The band structure of the second core-shell quantum dot exhibits strong confinement of holes but weaker confinement of electrons; a large number of holes are bound in the core, while a large number of electrons remain in the shell.

[0037] In some embodiments, the average particle size of the second core-shell quantum dot is 5 to 15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values.

[0038] The band structure of quantum dots can be detected using energy level detection methods commonly used in the field. For example, energy level detection can be performed on solutions containing quantum dots or thin films made based on quantum dots using ultraviolet photoelectron spectroscopy (UPS) to obtain information on the conduction band, valence band, and band gap of quantum dots.

[0039] The optoelectronic device 100 proposed in this application has superior luminescence performance and lifetime, and can meet various application scenarios by combining quantum dots. The optoelectronic device 100 proposed in this application has multiple implementations. For example, in some embodiments, the luminescent layer includes a first configuration quantum dot, and the optoelectronic device 100 can have superior luminescence performance. In other embodiments, the luminescent layer includes a second configuration quantum dot, resulting in a longer lifetime for the optoelectronic device 100. In still other embodiments, the luminescent functional layer may also include two or three luminescent layers, and at least two of the luminescent layers have different material configurations. For example, when the luminescent functional layer has two layers, one luminescent layer is made of a first configuration quantum dot, and the other luminescent layer is made of a second configuration quantum dot; or one luminescent layer is made of a first core-shell quantum dot, and the other luminescent layer is made of a second core-shell quantum dot; when the luminescent functional layer has three layers, the first luminescent layer is made of a first configuration quantum dot, the second luminescent layer is made of a first core-shell quantum dot, and the third luminescent layer is made of a second core-shell quantum dot.

[0040] Further, in some specific embodiments, the light-emitting functional layer may include at least one of a first light-emitting layer 71 and a second light-emitting layer 72, and a third light-emitting layer 30. The first light-emitting layer 71 is located between the third light-emitting layer 30 and the anode 10, and the second light-emitting layer 72 is located between the third light-emitting layer 30 and the cathode 20. Specifically: the first light-emitting layer 71 is made of a first core-shell quantum dot, which includes a first core and a first shell. The valence band of the first core is lower than the valence band of the first shell, and the conduction band of the first core is located within the band gap of the first shell. The second light-emitting layer 72 is made of a second core-shell quantum dot, which includes a second core and a second shell. The conduction band of the second core is higher than the conduction band of the second shell, and the valence band of the second core is located within the band gap of the second shell. The third light-emitting layer 30 is made of a first configuration quantum dot, which includes a third core and a third shell. The band gap of the third core is located within the band gap of the third shell.

[0041] The technical solution proposed in this application uses a first-configuration quantum dot in the third light-emitting layer 30, which has a strong confinement effect on both electrons and holes, thus helping to improve the luminous efficiency of the device. At the same time, a first core-shell quantum dot and a second core-shell quantum dot, which have a strong confinement effect on electrons or holes, are set on one side of the third light-emitting layer 30, thereby blocking excess electrons or holes and reducing the overlap of wave functions of electrons and holes, which helps to improve the lifetime of the device. Thus, the device has both high lifetime and high luminous efficiency.

[0042] The following will describe in detail the scheme based on the first light-emitting layer 71, the second light-emitting layer 72, and the third light-emitting layer 30 with reference to specific embodiments:

[0043] Please see Figure 1 In the first embodiment, the optoelectronic device 100 includes an anode 10, a first light-emitting layer 71, a third light-emitting layer 30 and a cathode 20 stacked together. The material of the third light-emitting layer 30 includes a first configuration quantum dot, and the material of the first light-emitting layer 71 includes a first core-shell quantum dot with a type II band structure.

[0044] In the third luminescent layer 30 prepared from the first configuration quantum dot, a large number of electrons and holes are bound in the core of the quantum dot, increasing the overlap of electron and hole wave functions. The recombination luminescent region is almost entirely located in the core, which is beneficial for achieving high luminous efficiency of the device. At the same time, the first luminescent layer 71 based on the first core-shell quantum dot is disposed between the third luminescent layer 30 and the anode 10, which can block excess electrons. In the case that the optoelectronic device 100 also includes a hole functional layer, it can prevent excess electrons from damaging the hole functional layer, thereby improving the carrier balance, which helps to extend the device's lifespan and further improve the device's luminous efficiency.

[0045] Please see Figure 2 In the second embodiment, the optoelectronic device 100 includes an anode 10, a third light-emitting layer 30, a second light-emitting layer 72, and a cathode 20 stacked together. The material of the third light-emitting layer 30 includes a first configuration quantum dot, and the material of the second light-emitting layer 72 includes a second core-shell quantum dot.

[0046] In the third light-emitting layer 30 prepared from the first configuration quantum dot, a large number of electrons and holes are bound in the core of the quantum dot, increasing the overlap of electron and hole wave functions. The recombination light-emitting region is almost entirely located in the core, which is beneficial for achieving high luminous efficiency of the device. At the same time, the second light-emitting layer 72 based on the second core-shell quantum dot is disposed between the third light-emitting layer 30 and the cathode 20, which can block excessive holes. In the case that the optoelectronic device 100 also includes an electron transport layer 60, it can prevent excessive holes from damaging the electron transport layer 60, thereby improving the carrier balance, which helps to extend the device's lifespan and further improve the device's luminous efficiency.

[0047] Please see Figure 3 In the third embodiment, the optoelectronic device 100 includes an anode 10, a first light-emitting layer 71, a third light-emitting layer 30, a second light-emitting layer 72, and a cathode 20 stacked together. The material of the third light-emitting layer 30 includes a first configuration quantum dot, the material of the first light-emitting layer 71 includes a first core-shell quantum dot, and the material of the second light-emitting layer 72 includes a second core-shell quantum dot.

[0048] The third light-emitting layer 30 based on the first configuration quantum dot helps to improve the luminous efficiency of the device; the first light-emitting layer 71 based on the first core-shell quantum dot is disposed between the third light-emitting layer 30 and the anode 10, which can block excess electrons. At the same time, the second light-emitting layer 72 based on the second core-shell quantum dot is disposed between the third light-emitting layer 30 and the cathode 20, which can block excess holes. This can improve the carrier balance, thereby helping to extend the lifespan of the device and further improve the luminous efficiency of the device.

[0049] To improve luminous efficiency and display effect, the absolute value of the PL peak values ​​of any two quantum dots in the luminescent functional layer is less than or equal to 3 nm. This prevents wavelength crosstalk and attenuation during luminescence from different quantum dots. In actual testing, the PL peak value of the quantum dot-based thin film can be obtained by using an Edinburgh spectrometer to test the PL spectrum.

[0050] In some embodiments, the light-emitting functional layer includes a first light-emitting layer 71 and a third light-emitting layer 30, wherein the absolute value of the difference between the PL peak value of the material of the third light-emitting layer 30 and the PL peak value of the material of the first light-emitting layer 71 is less than or equal to 3 nm. This ensures that the PL peak values ​​of the materials of the third light-emitting layer 30 and the first light-emitting layer 71 are consistent, preventing wavelength crosstalk and attenuation during quantum dot emission. In other embodiments, the light-emitting functional layer includes a second light-emitting layer 72 and a third light-emitting layer 30, wherein the absolute value of the difference between the PL peak value of the material of the third light-emitting layer 30 and the PL peak value of the material of the second light-emitting layer 72 is less than or equal to 3 nm. Therefore, the photoluminescence (PL) peak values ​​of the materials of the third luminescent layer 30 and the second luminescent layer 72 are kept consistent, which can prevent wavelength crosstalk and attenuation during quantum dot emission. In some other embodiments, the luminescent functional layer includes the first luminescent layer 71, the third luminescent layer 30, and the second luminescent layer 72. The absolute value of the difference between the PL peak values ​​of any two of the materials of the third luminescent layer 30, the first luminescent layer 71, and the second luminescent layer 72 is less than or equal to 3 nm. In this way, the PL peak values ​​of the materials of the third luminescent layer 30, the first luminescent layer 71, and the second luminescent layer 72 are kept consistent, which can prevent wavelength crosstalk and attenuation during quantum dot emission.

[0051] Furthermore, when the third light-emitting layer 30 contains two or more first configuration quantum dots, the absolute value of the difference between the PL peak values ​​of any two first configuration quantum dots is less than or equal to 3 nm; when the first light-emitting layer 71 contains two or more first core-shell quantum dots, the absolute value of the difference between the PL peak values ​​of any two first core-shell quantum dots is less than or equal to 3 nm; when the second light-emitting layer 72 contains two or more second core-shell quantum dots, the absolute value of the difference between the PL peak values ​​of any two second core-shell quantum dots is less than or equal to 3 nm.

[0052] In some embodiments, the PL peak value of the first configuration quantum dot is in the range of 400–700 nm; the PL peak value of the first core-shell quantum dot is in the range of 400–700 nm; and the PL peak value of the second core-shell quantum dot is in the range of 400–700 nm.

[0053] In some embodiments, the core material of the first configuration quantum dot, the shell material of the first configuration quantum dot, the material of the first core, the material of the first shell, the material of the second core, and the material of the second shell each independently include at least one of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds; the group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, and ZnS. At least one of the following: eS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds include SnS, SnSe, SnTe, PbS, Pb At least one of Se, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compound includes at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, and AlNSb. At least one of the following: AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; wherein the group I-III-VI compounds include at least one of CuInS2, CuInSe2, and AgInS2.

[0054] As an example, the first configuration quantum dot may include, but is not limited to, one or more of CdSe / CdS, CdSe / ZnS, ZnSe / ZnS, InP / ZnSe, and InP / ZnS. It is understood that in the term "quantum dot" as used herein, " / " indicates a coating structure; for example, CdSe / CdS indicates that the core material is CdSe and the shell material is CdS. Furthermore, in some embodiments, the absolute value of the conduction band difference between the core and shell of the first configuration quantum dot is 0.05 to 1.5 eV, for example, it may be 0.05 eV, 0.06 eV, 0.07 eV, 0.08 eV, 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, 0.7 eV, 0.8 eV, 0.9 eV, 1.0 eV, 1.1 eV, 1.2 eV, 1.3 eV, 1.4 eV, 1.5 eV, or any two of the above values. The absolute value of the valence band difference between the core and shell of the first configuration quantum dot is 0.05 to 2.5 eV; for example, it can be 0.05 eV, 0.06 eV, 0.07 eV, 0.08 eV, 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, 0.7 eV, 0.8 eV, 0.9 eV, 1.0 eV, 1.1 eV, 1.2 eV, 1.3 eV, 1.4 eV, 1.5 eV, 1.6 eV, 1.7 eV, 1.8 eV, 1.9 eV, 2.0 eV, 2.1 eV, 2.2 eV, 2.3 eV, 2.4 eV, 2.5 eV, or any two of the above values. In other embodiments, the absolute value of the conduction band difference between the first core and the first shell is 0.5 to 2.0 eV, for example, it can be 0.05 eV, 0.06 eV, 0.07 eV, 0.08 eV, 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, 0.7 eV, 0.8 eV, 0.9 eV, 1.0 eV, 1.1 eV, 1.2 eV, 1.3 eV, 1.4 eV, 1.5 eV, 1.6 eV, 1.7 eV, 1.8 eV, 1.9 eV, 2.0 eV, and any two of the above values. The absolute value of the valence band difference between the first core and the first shell is 0.1 to 2.0 eV; for example, it can be 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, 0.7 eV, 0.8 eV, 0.9 eV, 1.0 eV, 1.1 eV, 1.2 eV, 1.3 eV, 1.4 eV, 1.5 eV, 1.6 eV, 1.7 eV, 1.8 eV, 1.9 eV, 2.0 eV, or any two of the above values.In some embodiments, the absolute value of the conduction band difference between the second core and the second shell is 0.3–1.2 eV, for example, it can be 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, 0.7 eV, 0.8 eV, 0.9 eV, 1.0 eV, 1.1 eV, 1.2 eV, or any two of the above values. The absolute value of the valence band difference between the second core and the second shell is 0.8–2.0 eV; for example, it can be 0.8 eV, 0.9 eV, 1.0 eV, 1.1 eV, 1.2 eV, 1.3 eV, 1.4 eV, 1.5 eV, 1.6 eV, 1.7 eV, 1.8 eV, 1.9 eV, 2.0 eV, or any two of the above values. Controlling the core-shell energy level difference of the quantum dot within the above range results in better lattice matching of the core-shell structure, which is more conducive to carrier confinement and transport.

[0055] In some specific embodiments, a first configuration quantum dot with the following band characteristics and PL peak is further illustrated:

[0056] In CdSe / CdS: the conduction band energy level of the CdSe core is -4.6 eV, and the valence band energy level is -6.7 eV; the conduction band energy level of the CdS shell is -4.4 eV, and the valence band energy level is -6.9 eV; the PL peak is 537 nm.

[0057] In CdSe / ZnS: the CdSe core has a conduction band energy level of -4.6 eV and a valence band energy level of -6.7 eV; the ZnS shell has a conduction band energy level of -3.2 eV and a valence band energy level of -7.5 eV; the PL peak is 537 nm.

[0058] In ZnSe / ZnS: the conduction band energy level of the ZnSe core is -3.83 eV, and the valence band energy level is -6.77 eV; the conduction band energy level of the ZnS shell is -3.2 eV, and the valence band energy level is -7.5 eV; the PL peak is 535 nm.

[0059] In InP / ZnSe: the InP core has a conduction band energy level of -3.9 eV and a valence band energy level of -5.0 eV; the ZnSe shell has a conduction band energy level of -3.83 eV and a valence band energy level of -6.77 eV; the PL peak is 537 nm.

[0060] In InP / ZnS: the InP core has a conduction band energy level of -3.9 eV and a valence band energy level of -5.0 eV; the ZnS shell has a conduction band energy level of -3.2 eV and a valence band energy level of -7.5 eV; the PL peak is 535 nm.

[0061] As an example, the first core-shell quantum dot includes one or more of CdSe / ZnTe, CdSe / CdTe, and CdS / ZnSe. In some specific embodiments, a first core-shell quantum dot having the following band characteristics and PL peak is further listed:

[0062] In CdSe / ZnTe: the CdSe core has a conduction band energy level of -4.6 eV and a valence band energy level of -6.7 eV; the ZnTe shell has a conduction band energy level of -2.7 eV and a valence band energy level of -5.0 eV; the PL peak is 538 nm.

[0063] In CdSe / CdTe: the CdSe core has a conduction band energy level of -4.6 eV and a valence band energy level of -6.7 eV; the CdTe shell has a conduction band energy level of -4.1 eV and a valence band energy level of -5.9 eV; the PL peak is 538 nm.

[0064] In CdS / ZnSe: the conduction band energy level of the CdS core is -4.4 eV, and the valence band energy level is -6.9 eV; the conduction band energy level of the ZnSe shell is -3.83 eV, and the valence band energy level is -6.77 eV; the PL peak is 536 nm.

[0065] As an example, the second core-shell quantum dot includes one or more of CdTe / CdSe, ZnTe / ZnSe, CdTe / CdS, InP / CdSe, InP / CdS, and InAs / CdSe. In some specific embodiments, second core-shell quantum dots having the following band characteristics and PL peaks are further listed:

[0066] In CdTe / CdSe, the CdTe core has a conduction band energy level of -4.1 eV and a valence band energy level of -5.9 eV; the CdSe shell has a conduction band energy level of -4.6 eV and a valence band energy level of -6.7 eV; and the PL peak is 538 nm.

[0067] In ZnTe / ZnSe, the ZnTe core has a conduction band level of -2.7 eV and a valence band level of -5 eV; the ZnSe shell has a conduction band level of -3.83 eV and a valence band level of -6.77 eV; the PL peak is 536 nm.

[0068] In CdTe / CdS, the CdTe core has a conduction band energy level of -4.1 eV and a valence band energy level of -5.9 eV; the CdS shell has a conduction band energy level of -4.4 eV and a valence band energy level of -6.9 eV; the PL peak is 538 nm.

[0069] In InP / CdSe, the InP core has a conduction band energy level of -3.9 eV and a valence band energy level of -5.0 eV; the CdSe shell has a conduction band energy level of -4.6 eV and a valence band energy level of -6.7 eV; the PL peak is 537 nm.

[0070] In InP / CdS, the InP core has a conduction band energy level of -3.9 eV and a valence band energy level of -5.0 eV; the CdS shell has a conduction band energy level of -4.4 eV and a valence band energy level of -6.9 eV; the PL peak is 537 nm.

[0071] In InAs / CdSe: the conduction band energy level of the InAs core is -4.14 eV and the valence band energy level is -5.78 eV; the conduction band energy level of the CdSe shell is -4.6 eV and the valence band energy level is -6.7 eV; the PL peak is 537 nm.

[0072] It should be noted that the core or shell materials of the three quantum dots can also be ternary or higher-order systems, such as CdZnSe, CdZnS, and CdZnSeS. It is understood that the chemical formulas provided for the core or shell materials of the aforementioned core-shell quantum dots only indicate the elemental composition, not the content of each element. For example, CdZnSe only indicates that it is composed of Cd, Zn, and Se. If the content of each element were specified, it would correspond to Cd... x Zn 1- x Se, 0 <x<1。

[0073] The aforementioned quantum dots can be commercially available or prepared using commonly used quantum dot synthesis methods in this field. The preparation method includes: dispersing a nucleocation precursor in an organic solvent to prepare a nucleocation precursor solution; dispersing a nucleoanion precursor in an organic solvent to prepare a nucleoanion precursor solution; dispersing a shell cation precursor in an organic solvent to prepare a shell cation precursor solution; and dispersing a shell anion precursor in an organic solvent to prepare a shell anion precursor solution. The nucleocation precursor solution and the nucleoanion precursor solution are mixed to carry out a nucleation reaction, obtaining a core solution. The shell cation precursor solution and the shell anion precursor solution are then injected into the core solution to form a shell on the surface of the core, thus obtaining a core-shell structured quantum dot.

[0074] The nuclear cation precursor includes at least one of a cadmium source, a zinc source, and an indium source. The nuclear anion precursor includes at least one of a selenium source, a sulfur source, a tellurium source, a phosphorus source, and an arsenic source. The shell cation precursor includes at least one of a cadmium source, a zinc source, and an indium source. The shell anion precursor includes at least one of a selenium source, a sulfur source, a tellurium source, a phosphorus source, and an arsenic source. The cadmium source includes at least one of cadmium powder, cadmium oxide, cadmium chloride, cadmium oxalate, cadmium acetate, cadmium carbonate, cadmium stearate, cadmium acetylacetonate, and cadmium tetradecanoate. The zinc source includes at least one of zinc powder, zinc oxide, zinc chloride, zinc oxalate, zinc acetate, zinc carbonate, zinc stearate, zinc acetylacetonate, zinc tetradecanoate, and zinc undecenoate. The selenium source includes at least one of inorganic selenium, organophosphorus complexes of selenium, organoselenochemicals, and organoselenools. The sulfur source includes at least one of sulfur powder, sodium sulfide, sodium disulfide, and potassium sulfide. The tellurium source includes at least one of sodium tellurite, potassium tellurite, and zinc tellurite. It is understood that, in actual preparation, the precursor can be selected based on the types of cations and anions in the core or shell material. For example, in CdSe / ZnS, a cadmium source can be used as the nuclear cation precursor, a selenium source as the nuclear anion precursor, a zinc source as the shell cation precursor, and a sulfur source as the shell anion precursor.

[0075] The organic solvent may include, but is not limited to, one or more of organic compounds having 10 to 22 carbon atoms and lipophilic ligands, wherein the organic compound is selected from at least one of alkanes, alkenes, halogenated hydrocarbons, aromatic hydrocarbons, ethers, amines, ketones, and esters. As an example, the organic solvent is at least one of tetradecene, pentadecene, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, and paraffin oil. The lipophilic ligand may be any lipophilic ligand material known in the art for use in light-emitting diodes, for example, including but not limited to at least one of alkyl acids, alkylamines, alkyl thiols, phosphine, phosphine oxide, alkyl phosphoric acid, and stearic acid. Specifically, the alkyl group may represent a chain alkyl group or a cyclic alkyl group, wherein the chain alkyl group includes straight-chain alkyl groups and branched-chain alkyl groups. The number of carbon atoms in the alkyl group may be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. As an example, the lipophilic ligand may be oleic acid (OA), oleylamine (OAm), octylamine, trioctylphosphine (TOP), trioctylphosphine oxide (TOPO), etc.

[0076] The nucleation reaction can be carried out at a temperature of 180℃ to 320℃; the shell formation reaction can be carried out at a temperature of 240℃ to 320℃.

[0077] Based on the above preparation method, quantum dots with specific configurations and bandgap characteristics can be prepared, such as first-configuration quantum dots, first core-shell quantum dots, and second core-shell quantum dots. Furthermore, the injection amount of the shell precursor solution can be adjusted to control the shell thickness, thereby adjusting the PL peak value and achieving fine-tuning of the bandgap. In actual preparation, the injection amount can be adjusted by detecting the PL peak value of the product to control the PL peak value to the expected position.

[0078] In some embodiments, the thickness of the third light-emitting layer 30 is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. Controlling the thickness within this range not only allows for adjustment of carrier injection through the bandgap to prevent carrier tunneling, but also allows for regulation of carrier migration rates, thereby reducing device voltage. In this application, the thickness of the film layer can be obtained using a profilometer.

[0079] In some embodiments, the thickness of the first light-emitting layer 71 is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. Controlling it within this range not only allows for adjustment of carrier injection through the bandgap to prevent carrier tunneling, but also allows for regulation of carrier migration rate to reduce device voltage.

[0080] In some embodiments, the thickness of the second light-emitting layer 72 is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. Controlling the thickness within this range not only allows for adjustment of carrier injection through the bandgap to prevent carrier tunneling, but also allows for regulation of carrier migration rates, thereby reducing device voltage.

[0081] In some embodiments, the total thickness of the light-emitting functional layer can be 10–45 nm; for example, it can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 32 nm, 35 nm, 38 nm, 40 nm, 43 nm, 45 nm, or any two of the above values. Further, in other embodiments, the total thickness of the light-emitting functional layer can be 30–45 nm.

[0082] The first light-emitting layer 71 can be a single-layer film or a multi-layer film. Please refer to [link / reference]. Figure 4 In some embodiments, the first light-emitting layer 71 includes at least one first sub-light-emitting layer 711, and the material of each first sub-light-emitting layer 711 is independently selected from the first core-shell quantum dot.

[0083] When the first light-emitting layer 71 includes multiple first sub-light-emitting layers 711, the absolute value of the difference between the PL peak values ​​of any two first sub-light-emitting layers 711 is less than or equal to 3 nm; and when the first light-emitting layer 71 contains multiple first core-shell quantum dots, the absolute value of the difference between the PL peak values ​​of any two first core-shell quantum dots is less than or equal to 3 nm.

[0084] The thickness of the first sub-light-emitting layer 711 is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. When the first light-emitting layer 71 contains at least one first sub-light-emitting layer 711, the total thickness of the at least one first sub-light-emitting layer 711 is the thickness of the first light-emitting layer 71, and the total thickness of the first light-emitting layer 71 is controlled within the range of 5 to 15 nm.

[0085] The second light-emitting layer 72 can be a single-layer film or a multi-layer film. In some embodiments, the second light-emitting layer 72 includes at least one second sub-light-emitting layer 721, and the material of each second sub-light-emitting layer 721 is independently selected from the second core-shell quantum dot.

[0086] When the second light-emitting layer 72 includes multiple layers of the second sub-light-emitting layer 721, the absolute value of the difference between the PL peak values ​​of any two materials of the second sub-light-emitting layer 721 is less than or equal to 3 nm; and when the second light-emitting layer 72 contains multiple second core-shell quantum dots, the absolute value of the difference between the PL peak values ​​of any two second core-shell quantum dots is less than or equal to 3 nm.

[0087] The thickness of the second sub-light-emitting layer 721 is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. When the second light-emitting layer 72 contains at least one second sub-light-emitting layer 721, the total thickness of the at least one second sub-light-emitting layer 721 is equal to the thickness of the second light-emitting layer 72, and the total thickness of the second light-emitting layer 72 is controlled within the range of 5–15 nm.

[0088] The third light-emitting layer 30 can be a single-layer film or a multi-layer film. In some embodiments, the third light-emitting layer 30 includes at least one third sub-light-emitting layer 31, and the material of each third sub-light-emitting layer 31 is independently selected from the first configuration quantum dots.

[0089] When the third light-emitting layer 30 includes multiple third sub-light-emitting layers 31, the absolute value of the difference between the PL peak values ​​of any two materials of the third sub-light-emitting layers 31 is less than or equal to 3 nm; and when the third light-emitting layer 30 contains multiple first configuration quantum dots, the absolute value of the difference between the PL peak values ​​of any two first configuration quantum dots is less than or equal to 3 nm.

[0090] The thickness of the third sub-light-emitting layer 31 is 5–15 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any two of the above values. When the third light-emitting layer 30 contains at least one third sub-light-emitting layer 31, the total thickness of the at least one third sub-light-emitting layer 31 is equal to the thickness of the third light-emitting layer 30, and the total thickness of the third light-emitting layer 30 is controlled within the range of 5 to 15 nm.

[0091] In some embodiments, the anode 10 and the cathode 20 can be selected from anodes 10 or cathodes commonly used in the art. Specifically, the anode 10 and the cathode 20 can each be independently selected from, but not limited to, doped metal oxide particle electrodes, composite electrodes of metal and metal oxides, graphene electrodes, carbon nanotube electrodes, metal electrodes, or alloy electrodes. The material of the doped metal oxide particle electrode is selected from indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped... The metal and metal oxide composite electrode is selected from one or more of magnesium oxides, including AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba. Here, " / " indicates a stacked structure; for example, the composite electrode AZO / Ag / AZO represents a three-layer stacked composite structure consisting of an AZO layer, an Ag layer, and an AZO layer. The thickness of the anode 10 can be 100–150 nm; for example, it can be 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, or any two of the above values. The thickness of the cathode 20 can be 10 to 120 nm; for example, it can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, or any two of the above values.

[0092] In some embodiments, the optoelectronic device 100 may further include a hole functional layer disposed between the light-emitting functional layer and the anode 10, the hole functional layer including one or both of a hole injection layer 50 and a hole transport layer 40. When the hole functional layer includes a hole injection layer 50 and a hole transport layer 40, the hole injection layer 50 is located between the hole transport layer 40 and the anode 10.

[0093] The material of the hole transport layer 40 can be selected from organic materials with hole transport capabilities, including but not limited to 4,4'-N,N'-dicarbazolyl-biphenyl (CBP), poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine (α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)- 4,4'-Diamine (TPD), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro(spiro-TPD), N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTPD), 4,4',4”-tris[(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), poly(p-)phenylethyleneethylene ( PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MOMO-PPV), 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS, poly(N-vinylcarbazole) (PVK), polymethacrylate, poly(9,9-octylfluorene), N,N'-di(naphthyl-1-yl)-N, N'-Diphenylbenzidine (NPB), spiroNPB, doped graphene, undoped graphene, and C60 are selected as one or more. The material of the hole transport layer 40 may also be selected from inorganic materials with hole transport capabilities, including but not limited to one or more of doped or undoped NiO, WO3, MoO3, and CuO. The thickness of the hole transport layer 40 is 20–60 nm; for example, it can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, or any two of the above values.

[0094] The material of the hole injection layer 50 can be selected from materials with hole injection capability, including but not limited to poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethylethane (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene (HATCN), copper polyester carbonate (CuPc), transition metal oxides, and metal chalcogenides; wherein the transition metal oxides include one or more of NiO, MoO2, WO3, and CuO; and the metal chalcogenides include one or more of MoS2, MoSe2, WS3, WSe3, and CuS. The thickness of the hole injection layer 50 is 20-60 nm; for example, it can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, or any two of the above values.

[0095] In some embodiments, the optoelectronic device 100 further includes an electron transport layer 60 disposed between the light-emitting functional layer and the cathode 20. The material of the electron transport layer 60 includes at least one of a metal oxide and a doped metal oxide. The metal oxide includes one or more of ZnO, TiO2, and SnO2. The doped metal oxide includes one or more of ZnO, TiO2, and SnO2. The doping element includes one or more of Al, Mg, Li, In, and Ga. The thickness of the electron transport layer 60 is 20–60 nm; for example, it can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, or any two of the above values.

[0096] It is understood that the optoelectronic device 100 may also be provided with some functional layers that are conventionally used in optoelectronic devices 100 and help to improve the performance of optoelectronic devices 100, such as electron blocking layer, hole blocking layer, interface modification layer, etc.

[0097] It is understood that the materials of each layer of the optoelectronic device 100 can be adjusted according to the actual needs of the optoelectronic device 100.

[0098] It is understood that the optoelectronic device 100 can be an upright device or an inverted device.

[0099] This application also proposes a method for fabricating an optoelectronic device 100, the method comprising the following steps:

[0100] S1 provides the first electrode;

[0101] S2, depositing a multilayer film material on one side of the first electrode to form a light-emitting functional layer, the light-emitting functional layer including at least two light-emitting layers;

[0102] S3, a second electrode is disposed on the side of the light-emitting functional layer opposite to the first electrode;

[0103] The first electrode is selected from one of the anode 10 and the cathode 20, and the second electrode is selected from the other of the anode 10 and the cathode 20. The multilayer film materials are each independently selected from a first configuration quantum dot or a second configuration quantum dot, wherein the first configuration quantum dot and the second configuration quantum dot are core-shell structured quantum dots, and the band gap of the core of the first configuration quantum dot is located between the band gaps of the shell of the first configuration quantum dot, and the valence band edge or conduction band edge of the shell of the second configuration quantum dot is located between the band gaps of the core of the second configuration quantum dot.

[0104] Furthermore, in some embodiments, when the light-emitting functional layer includes a first light-emitting layer 71, a second light-emitting layer 72, and a third light-emitting layer 73, the preparation method may include the following steps:

[0105] S10 provides the first electrode;

[0106] S20, according to the film layer sequence, deposit multiple layers of film material on one side of the first electrode to form a light-emitting functional layer, the light-emitting functional layer including at least one of the first light-emitting layer 71 and the second light-emitting layer 72 and the third light-emitting layer 30.

[0107] S30, a second electrode is disposed on the side of the light-emitting functional layer opposite to the first electrode;

[0108] Wherein, the first electrode is selected from one of the anode 10 and the cathode 20, and the second electrode is selected from the other of the anode 10 and the cathode 20; and the film layer sequence is as follows: the first light-emitting layer 71 is located between the third light-emitting layer 30 and the anode 10, and the second light-emitting layer 72 is located between the third light-emitting layer 30 and the cathode 20;

[0109] The multilayer film materials satisfy the following conditions: the material of the first light-emitting layer 71 includes a first core-shell quantum dot, the first core-shell quantum dot includes a first core and a first shell, the valence band of the first core is lower than the valence band of the first shell, and the conduction band of the first core is located between the band gaps of the first shell; the material of the second light-emitting layer 72 includes a second core-shell quantum dot, the second core-shell quantum dot includes a second core and a second shell, the conduction band of the second core is higher than the conduction band of the second shell, and the valence band of the second core is located between the band gaps of the second shell; the material of the third light-emitting layer 30 includes a first configuration quantum dot, the first configuration quantum dot includes a third core and a third shell, and the band gap of the third core is located between the band gaps of the third shell.

[0110] The band structure characteristics and specific types of the first configuration quantum dot, the first core-shell quantum dot, and the second core-shell quantum dot have been described in detail above and will not be repeated here.

[0111] Specifically, the light-emitting functional layer includes the fabrication of a third light-emitting layer 30, and the fabrication of a first light-emitting layer 71 and / or a second light-emitting layer 72. In actual fabrication, the light-emitting functional layer is obtained by sequentially fabricating the film layers according to their order. For example, when the light-emitting functional layer includes a first light-emitting layer 71, a third light-emitting layer 30, and a second light-emitting layer 72, the fabrication of the light-emitting functional layer includes: sequentially fabricating the first light-emitting layer 71, the third light-emitting layer 30, and the second light-emitting layer 72 on one side of the first electrode.

[0112] In some embodiments, the preparation of the third light-emitting layer 30 includes: providing the first configuration quantum dots and a first solvent, dispersing the first configuration quantum dots in the first solvent to form a first mixed solution; depositing the first mixed solution and curing it to obtain the third light-emitting layer 30.

[0113] In the first mixed solution, the concentration of the first configuration quantum dots is 5 to 30 mg / mL; for example, 5 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, and any two of the above values.

[0114] The first solvent may include, but is not limited to, one or more of the following: straight-chain alkane solvents with 8 to 16 carbon atoms, branched alkane solvents with 8 to 16 carbon atoms, cycloalkane solvents with 5 to 16 carbon atoms, and aromatic solvents with 7 to 16 carbon atoms; the straight-chain alkane solvents with 8 to 16 carbon atoms are selected from one or more of octane, nonane, decane, undecane, dodecane, tridecane, and tetradecane; the branched alkane solvents with 8 to 16 carbon atoms are selected from one or more of 2-methyloctane, 3-ethylheptane, 2,2-dimethyloctane, and 1-cyclohexyldecane; the cycloalkane solvents with 5 to 16 carbon atoms are selected from one or two of cyclooctane, cycloheptane, cyclohexane, and cyclopentane; and the aromatic solvents with 7 to 16 carbon atoms are selected from one or more of octylbenzene, toluene, and xylene.

[0115] Deposition methods can include spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating.

[0116] Depositing the first mixed solution can form a liquid film. The curing step may include: annealing the liquid film, followed by ultraviolet (UV) irradiation curing. The annealing temperature can be 80–120°C; for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, or any two of the above values. The annealing time can be 5–30 min; for example, it can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, or any two of the above values. The UV irradiation time can be 10–30 min; for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, or any two of the above values.

[0117] Further, when the third light-emitting layer 30 includes at least one third sub-light-emitting layer 31, the preparation of the third light-emitting layer 30 may include: providing at least one third sub-light-emitting layer 31 material, sequentially depositing at least one third sub-light-emitting layer 31 material to obtain at least one third sub-light-emitting layer 31, wherein each of the third sub-light-emitting layer 31 materials is independently selected from the first configuration quantum dots. The preparation of each third sub-light-emitting layer 31 can refer to the preparation method of the monolayer film third light-emitting layer 30 described above. For example, the corresponding third sub-light-emitting layer 31 material is dispersed in a first solvent to form a mixed solution, then deposited, followed by annealing and ultraviolet irradiation to obtain the third sub-light-emitting layer 31, and the next third sub-light-emitting layer 31 is prepared on the surface of the third sub-light-emitting layer 31.

[0118] In some embodiments, the preparation of the first light-emitting layer 71 includes: providing the first core-shell quantum dots and a second solvent, dispersing the first core-shell quantum dots in the second solvent to form a second mixed solution; depositing the second mixed solution and curing it to obtain the first light-emitting layer 71.

[0119] In the second mixed solution, the concentration of the first core-shell quantum dots is 5 to 30 mg / mL; for example, 5 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, and any two of the above values.

[0120] The second solvent may include, but is not limited to, one or more of the following: straight-chain alkane solvents with 8 to 16 carbon atoms, branched alkane solvents with 8 to 16 carbon atoms, cycloalkane solvents with 5 to 16 carbon atoms, and aromatic solvents with 7 to 16 carbon atoms; the straight-chain alkane solvents with 8 to 16 carbon atoms are selected from one or more of octane, nonane, decane, undecane, dodecane, tridecane, and tetradecane; the branched alkane solvents with 8 to 16 carbon atoms are selected from one or more of 2-methyloctane, 3-ethylheptane, 2,2-dimethyloctane, and 1-cyclohexyldecane; the cycloalkane solvents with 5 to 16 carbon atoms are selected from one or two of cyclooctane, cycloheptane, cyclohexane, and cyclopentane; and the aromatic solvents with 7 to 16 carbon atoms are selected from one or more of octylbenzene, toluene, and xylene.

[0121] Depositing the second mixed solution can form a liquid film. The curing step may include: annealing the liquid film, followed by ultraviolet (UV) irradiation curing. The annealing temperature can be 80–120°C; for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, or any two of the above values. The annealing time can be 5–30 min; for example, it can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, or any two of the above values. The UV irradiation time can be 10–30 min; for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, or any two of the above values.

[0122] Furthermore, when the first light-emitting layer 71 includes at least one first sub-light-emitting layer 711, the preparation of the first light-emitting layer 71 includes: providing at least one first sub-light-emitting layer 711 material, sequentially depositing at least one first sub-light-emitting layer 711 material to obtain at least one first sub-light-emitting layer 711, wherein each first sub-light-emitting layer 711 material is independently selected from the first core-shell quantum dot.

[0123] In some embodiments, the preparation of the second light-emitting layer 72 includes: providing the second core-shell quantum dots and a third solvent, dispersing the second core-shell quantum dots in the third solvent to form a third mixed solution; depositing the third mixed solution and curing it to obtain the second light-emitting layer 72.

[0124] In the third mixed solution, the concentration of the second core-shell quantum dots is 5 to 30 mg / mL; for example, 5 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, and any two of the above values.

[0125] The third solvent may include, but is not limited to, one or more of the following: straight-chain alkane solvents with 8 to 16 carbon atoms, branched alkane solvents with 8 to 16 carbon atoms, cycloalkane solvents with 5 to 16 carbon atoms, and aromatic solvents with 7 to 16 carbon atoms; the straight-chain alkane solvents with 8 to 16 carbon atoms are selected from one or more of octane, nonane, decane, undecane, dodecane, tridecane, and tetradecane; the branched alkane solvents with 8 to 16 carbon atoms are selected from one or more of 2-methyloctane, 3-ethylheptane, 2,2-dimethyloctane, and 1-cyclohexyldecane; the cycloalkane solvents with 5 to 16 carbon atoms are selected from one or two of cyclooctane, cycloheptane, cyclohexane, and cyclopentane; and the aromatic solvents with 7 to 16 carbon atoms are selected from one or more of octylbenzene, toluene, and xylene.

[0126] Depositing the third mixed solution can form a liquid film. The curing step may include: annealing the liquid film, followed by ultraviolet (UV) irradiation curing. The annealing temperature can be 80–120°C; for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, or any two of the above values. The annealing time can be 5–30 min; for example, it can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, or any two of the above values. The UV irradiation time can be 10–30 min; for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, or any two of the above values.

[0127] Further, when the second light-emitting layer 72 includes at least one second sub-light-emitting layer 721, the preparation of the second light-emitting layer 72 includes: providing at least one second sub-light-emitting layer 721 material, sequentially depositing at least one second sub-light-emitting layer 721 material to obtain at least one second sub-light-emitting layer 721, wherein each second sub-light-emitting layer 721 material is independently selected from the second core-shell quantum dot.

[0128] In addition, the methods for forming the anode 10, cathode 20, and third light-emitting layer 30 can be chemical or physical methods. Chemical methods include chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods include physical deposition or solution processing. Physical deposition methods include thermal evaporation deposition (CVD), electron beam evaporation deposition, magnetron sputtering, multi-arc ion deposition, physical vapor deposition (PVD), atomic layer deposition, and pulsed laser deposition. Solution processing methods include spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating. Those skilled in the art can prepare the various film layers of the optoelectronic device 100 of this application embodiment according to the known methods for preparing optoelectronic devices 100, which will not be elaborated here.

[0129] Thirdly, this application also relates to a display device, which includes the optoelectronic device 100 provided in this application, or the optoelectronic device 100 prepared by the preparation method described above. The display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0130] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0131] Example 1

[0132] Step S1: Ultrasonically clean the substrate coated with ITO using acetone and ethanol for 15 minutes, then clean it with deionized water, blow it dry, dry it at 150°C for 10 minutes, and finally irradiate it with ultraviolet light (UV) for 20 minutes to form an anode.

[0133] Step S2: Using spin coating, hole injection material PEDOT:PSS is spin-coated onto the anode at a speed of 3000 rpm, followed by heating at 150°C for 20 min to obtain a hole injection layer with a thickness of approximately 32 nm.

[0134] Step S3: Spin-coat a chlorobenzene solution of TFB (TFB concentration of 8 mg / mL) onto the hole injection layer at a speed of 4000 rpm, and then heat at 150 °C for 30 min to obtain a hole transport layer with a thickness of approximately 27 nm.

[0135] Step S4: Mix 0.25g of tri-n-octylphosphine oxide (TOPO), 1.2946g of octadecylphosphonic acid (ODPA), and 0.2054g of CdO, and then heat to 320℃ to obtain a Cd precursor solution; disperse Se powder in tri-n-octylphosphine (TOP) and stir until dissolved to obtain a Se-TOP precursor solution with a Se concentration of 2 mol / L; disperse tellurium powder in TOP to obtain a Te-TOP precursor solution with a Te concentration of 1.2 mol / L.

[0136] Cd and Se precursor solutions were mixed at a molar ratio of Cd:Se = 2:1 and reacted at 300°C to obtain a core solution containing CdSe cores. 3.125 g TOPO, 2.875 g hexadecylamine (HDA), and 0.2825 g hexadecylamine (HPA) were mixed to form a mixed solution. The core solution was injected into the mixed solution, and the mixture was heated to 190°C. Then, at a molar ratio of Cd:Te = 1:1, the Cd and Te precursor solutions were continuously added to the reaction flask containing CdSe cores using a syringe. The reaction was carried out at 260°C for 20 min to obtain the quantum dot material CdSe / CdTe. The energy levels of the aforementioned quantum dot materials were detected using ultraviolet photoelectron spectroscopy (UPS). Simultaneously, the PL spectra of the quantum dot materials were measured using an Edinburgh spectrometer, revealing a PL peak at 538 nm. The conduction band energy level of the CdSe core was -4.6 eV, and the valence band energy level was -6.7 eV. The conduction band energy level of the CdTe shell was -4.1 eV, and the valence band energy level was -5.9 eV. The quantum dot materials CdSe / CdTe are first-core-shell quantum dots with a type II band structure, and are named type II-1 quantum dot materials CdSe / CdTe.

[0137] Type II-1 quantum dot materials CdSe / CdTe were dispersed in n-hexane to prepare a first solution with a concentration of 10 mg / mL. The first solution was spin-coated onto the hole transport layer at 2800 rpm, followed by heating at 100 °C for 5 min and then UV irradiation for 15 min to obtain a first emitting layer with a thickness of approximately 12 nm.

[0138] Step S5: Disperse 0.12g of dimethylcadmium in 3mL of TOP to prepare a Cd precursor solution; disperse 0.15g of selenium powder in 2mL of TOP to prepare a Se precursor solution; add the Cd precursor solution and the Se precursor solution to a mixed solution of 5g of HDA and 8g of TOPO, and react at 260℃ for 30min to obtain a core solution containing CdSe cores; place the core solution in a reaction flask, heat to 140℃, and slowly inject H2S into the reaction flask using a syringe, react for 30min to obtain CdSe / CdS quantum dots with a PL peak of 537nm. The CdSe core's conduction band energy level is -4.6eV and its valence band energy level is -6.7eV; the CdS shell's conduction band energy level is -4.4eV and its valence band energy level is -6.9eV. The temperature was then lowered to 100°C and stirred for 1 hour. The reaction mixture was then cooled to 50°C, 15 mL of chloroform was added, and finally, a 0.2 μm filter was used to obtain CdSe / CdS core-shell quantum dots with a type I band structure.

[0139] Type I quantum dots CdSe / CdS were dispersed in n-hexane to prepare a second solution with a concentration of 10 mg / mL. The second solution was then spin-coated onto the first luminescent layer at 2800 rpm, followed by heating at 100 °C for 5 min and then UV irradiation for 15 min to obtain a third luminescent layer with a thickness of approximately 12 nm.

[0140] Step S6: Following step S4, CdTe / CdSe quantum dots were prepared. The PL peak of the CdTe / CdSe quantum dots was detected to be 538 nm. The energy level information of these quantum dots is as follows: the conduction band energy level of the CdTe core is -4.1 eV, and the valence band energy level is -5.9 eV; the conduction band energy level of the CdSe shell is -4.6 eV, and the valence band energy level is -6.7 eV. This indicates a type II core-shell quantum dot with a type II band structure, named a type II-2 quantum dot. Specifically, in preparing the core, cadmium acetylacetonate was used as the Cd precursor to prepare a Cd precursor solution; in preparing the shell, the Cd precursor solution and the Se precursor solution were used as the cation precursor solution and anion precursor solution, respectively.

[0141] Type II-2 quantum dots CdTe / CdSe were dispersed in n-hexane to prepare a third solution with a concentration of 10 mg / mL. The third solution was then spin-coated onto the third luminescent layer at 2800 rpm, followed by heating at 100 °C for 5 min, and then UV irradiation for 15 min to obtain a second luminescent layer with a thickness of approximately 12 nm. The first, third, and second luminescent layers together constitute the luminescent functional layer.

[0142] Step S7: Spin-coat an ethanol solution of ZnMgO (ZnMgO concentration of 15 mg / mL) onto the second luminescent layer at a speed of 6000 rpm and heat at 80°C for 10 min to obtain an electron transport layer with a thickness of approximately 37 nm.

[0143] Step S8: Through thermal evaporation, the vacuum level is not higher than 3×10. -4 Pa was used to deposit Ag on the electron transport layer at a rate of 0.8 Å / s to obtain a cathode with a thickness of approximately 100 nm. The cathode was then encapsulated with acrylic resin to obtain a quantum dot light-emitting diode.

[0144] Example 2

[0145] The scheme of this embodiment is basically the same as that of embodiment 1. The only difference is that in this embodiment, the first light-emitting layer is removed. Correspondingly, in the preparation method, step S4 is deleted, and the third light-emitting layer is directly prepared on the hole transport layer.

[0146] Example 3

[0147] The scheme of this embodiment is basically the same as that of embodiment 1, except that the second light-emitting layer is removed in this embodiment. Correspondingly, in the preparation method, step S6 is deleted, and the electron transport layer is directly prepared on the third light-emitting layer.

[0148] Example 4

[0149] This embodiment is basically the same as embodiment 1, except that in this embodiment, the material of the first light-emitting layer is changed to the first core-shell quantum dot CdS / ZnSe, the material of the third light-emitting layer is changed to the first configuration quantum dot ZnSe / ZnS, and the material of the second light-emitting layer is changed to the second core-shell quantum dot InP / CdSe; wherein:

[0150] In the first core-shell quantum dot CdS / ZnSe, the CdS core has a conduction band energy level of -4.4 eV and a valence band energy level of -6.9 eV; the ZnSe shell has a conduction band energy level of -3.83 eV and a valence band energy level of -6.77 eV; the PL peak is 536 nm.

[0151] In the first configuration of quantum dots ZnSe / ZnS: the ZnSe core has a conduction band energy level of -3.83 eV and a valence band energy level of -6.77 eV; the ZnS shell has a conduction band energy level of -3.2 eV and a valence band energy level of -7.5 eV; the PL peak is 535 Ω.

[0152] In the second core-shell quantum dot InP / CdSe, the InP core has a conduction band energy level of -3.9 eV and a valence band energy level of -5.0 eV; the CdSe shell has a conduction band energy level of -4.6 eV and a valence band energy level of -6.7 eV; and the PL peak is 537 nm.

[0153] Example 5

[0154] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the material of the first light-emitting layer is changed to the first core-shell quantum dot CdSe / ZnTe, the material of the third light-emitting layer is changed to the first configuration quantum dot InP / ZnS, and the material of the second light-emitting layer is changed to the second core-shell quantum dot CdTe / CdS.

[0155] In the first core-shell quantum dot CdSe / ZnTe, the CdSe core has a conduction band level of -4.6 eV and a valence band level of -6.7 eV; the ZnTe shell has a conduction band level of -2.7 eV and a valence band level of -5.0 eV; the PL peak is 538 nm.

[0156] In the first configuration of quantum dot InP / ZnS, the InP core has a conduction band energy level of -3.9 eV and a valence band energy level of -5.0 eV; the ZnS shell has a conduction band energy level of -3.2 eV and a valence band energy level of -7.5 eV; the PL peak is 535 nm.

[0157] In the second core-shell quantum dot CdTe / CdS, the CdTe core has a conduction band energy level of -4.1 eV and a valence band energy level of -5.9 eV; the CdS shell has a conduction band energy level of -4.4 eV and a valence band energy level of -6.9 eV; and the PL peak is 538 nm.

[0158] Example 6

[0159] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the first light-emitting layer is composed of two sub-layers with a thickness of 6nm. The material of the sub-layer near the hole transport layer is CdSe / CdTe, and the material of the sub-layer near the third light-emitting layer is CdS / ZnSe.

[0160] Example 7

[0161] The scheme in this embodiment is basically the same as that in embodiment 1, except that in this embodiment, the third light-emitting layer is composed of two sub-layers with a thickness of 6nm. The material of the sub-layer closer to the first light-emitting layer is CdSe / CdS, and the material of the sub-layer closer to the second light-emitting layer is ZnSe / ZnS.

[0162] Example 8

[0163] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the second light-emitting layer is composed of two sub-layers with a thickness of 6nm, the material of the sub-layer near the third light-emitting layer is CdTe / CdSe, and the material of the sub-layer near the electron transport layer is CdTe / CdS.

[0164] Example 9

[0165] The scheme in this embodiment is basically the same as that in Embodiment 1, except that the first and second light-emitting layers are removed, and the thickness of the third light-emitting layer is changed to 36 nm. Accordingly, steps S4 and S6 are omitted, and a third light-emitting layer with a thickness of 36 nm is directly prepared on the hole transport layer, and an electron transport layer is prepared on the third light-emitting layer.

[0166] Example 10

[0167] The scheme of this embodiment is basically the same as that of embodiment 1. The only difference is that in this embodiment, the third light-emitting layer is removed. Correspondingly, in the preparation method, step S5 is deleted, and the second light-emitting layer is prepared directly on the first light-emitting layer.

[0168] Example 11

[0169] The scheme in this embodiment is basically the same as that in Embodiment 1, except that the third and second light-emitting layers are removed, and the thickness of the first light-emitting layer is changed to 36 nm. Accordingly, steps S5 and S6 are omitted, and a first light-emitting layer with a thickness of 36 nm is directly prepared on the hole transport layer, and an electron transport layer is prepared on the first light-emitting layer.

[0170] Example 12

[0171] This embodiment is basically the same as Embodiment 1, except that the first and third light-emitting layers are removed, and the thickness of the second light-emitting layer is changed to 36 nm. Accordingly, steps S4 and S5 are omitted, and a second light-emitting layer with a thickness of 36 nm is directly prepared on the hole transport layer, and an electron transport layer is prepared on the second light-emitting layer.

[0172] Example 13

[0173] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the first light-emitting layer is located between the electron transport layer and the third light-emitting layer, and the second light-emitting layer is located between the hole transport layer and the third light-emitting layer. Accordingly, in steps S4 to S6, the second light-emitting layer is first prepared on the hole transport layer using a third solution containing type II-2 quantum dots CdTe / CdSe, the third light-emitting layer is then prepared on the second light-emitting layer, and finally the first light-emitting layer is prepared on the third light-emitting layer using a first solution containing type II-1 quantum dots CdSe / CdTe.

[0174] Experimental Example

[0175] The QLED devices prepared in the above embodiments were subjected to performance testing, and the results are shown in Table 1. The testing methods are as follows:

[0176] (1) The current efficiency CE is tested by using the FPD optical characteristic measurement equipment, and using LabVIEW to control the QE PRO spectrometer, Keithley 2400 and Keithley 6485 to build an efficiency test system. The voltage, current, brightness and emission spectrum parameters are measured and the current efficiency is calculated.

[0177] (2) Lifetime: The test environment was 25℃, 60% RH, with a constant 2mA current driving the QLED device. A silicon photonics system was used to test the brightness change of the QLED device. The time required for the brightness to decay from 100% to 95% of its maximum value after power-on was recorded as T95. This lifetime is the measured lifetime. To shorten the testing cycle, device lifetime testing is usually performed by accelerating device aging under high brightness, referencing OLED device testing. The lifetime under high brightness is obtained by fitting the extended exponential decay brightness decay fitting formula, for example, the lifetime at 1000 nits is recorded as T95. 1000nit The specific calculation formula is as follows:

[0178]

[0179] In the formula, T95 L For longer lifespan at low brightness, T95 H For the measured lifetime under high brightness, L H To accelerate the device to its maximum brightness, L L The value is 1000 nits, and A is the acceleration factor. For OLEDs, this value is usually 1.6 to 2. In this experiment, the lifetime of several groups of QLED devices under rated brightness was measured, and the value of A was found to be 1.7.

[0180] The life test system was used to test the life of the corresponding devices. The test conditions were: room temperature and air humidity of 30-60%.

[0181] Table 1

[0182] CE (cd / A) T95 (h) [T95 1000nit (h)]]> Example 1 237 14.8 27929 Example 2 210 13.1 27099 Example 3 219 13.5 27527 Example 4 231 14.3 27894 Example 5 225 13.8 27803 Example 6 182 10.4 24893 Example 7 190 11.5 25327 Example 8 184 11.1 25014 Example 9 117 4.5 12536 Example 10 96 6.1 15800 Example 11 93 5.4 14827 Example 12 91 5.2 14730 Example 13 57 2.1 9225

[0183] As can be seen from the table above:

[0184] The devices in each embodiment all exhibit good luminous efficiency and lifetime, indicating that the optoelectronic devices proposed in this application have superior performance. Furthermore, the devices in embodiments 1 to 8 all demonstrate superior performance in luminous efficiency and lifetime, embodiment 9 exhibits strong luminous efficiency, and embodiments 10 to 12 show outstanding lifetime performance. Meanwhile, embodiment 13 exhibits a lower turn-on voltage during testing (reaching 3.4V, lower than 5.9V in embodiment 1, 4.7V in embodiment 9, and 5.0V in embodiment 10), demonstrating that the optoelectronic devices proposed in this application can meet different needs by adjusting the quantum dot configuration.

[0185] Furthermore, comparing Examples 1 to 9, it was found that the device structures of Examples 1 to 8 showed significant improvements in luminous efficiency and lifetime compared to Example 9. This indicates that the configuration matching method proposed in this application not only achieves high luminous efficiency with the help of the first configuration quantum dot, but also helps to improve the carrier injection balance. Excess carriers can be confined to the first core-shell quantum dot and the second core-shell quantum dot with type II band structure, respectively, avoiding the damage of excess carriers to the hole and electron functional layers. Therefore, the luminous efficiency and lifetime of the device are significantly improved. Meanwhile, compared to Example 9, the devices of Examples 10 to 12 show significant improvements in luminous efficiency and lifetime. The significant decrease in efficiency indicates that using the first configuration quantum dot in the light-emitting functional layer helps improve the luminous efficiency of the device. In addition, compared with Example 1, Example 13 not only showed a significant decrease in luminous efficiency but also a substantial reduction in lifetime. This indicates that placing the first core-shell quantum dot between the third light-emitting layer and the anode, and placing the second core-shell quantum dot between the third light-emitting layer and the cathode, can effectively block excess carriers. Otherwise, if the positions of the two film layers are interchanged, the light-emitting functional layer will completely lose its confinement effect on the corresponding carriers, and instead accelerate the damage of the functional layer by excess carriers, resulting in a decrease in the device's luminous performance and lifetime.

[0186] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An optoelectronic device, characterized in that, It includes a stacked anode, a light-emitting functional layer, and a cathode. The light-emitting functional layer includes at least two light-emitting layers, and the material of each light-emitting layer is independently selected from a first configuration quantum dot or a second configuration quantum dot, wherein: The first configuration quantum dot and the second configuration quantum dot are core-shell structured quantum dots, and the band gap of the core of the first configuration quantum dot is located between the band gaps of the shell of the first configuration quantum dot, and the valence band edge or conduction band edge of the shell of the second configuration quantum dot is located between the band gaps of the core of the second configuration quantum dot.

2. The optoelectronic device according to claim 1, characterized in that, The second configuration quantum dot includes one of a first core-shell quantum dot and a second core-shell quantum dot; the first core-shell quantum dot includes a first core and a first shell, the valence band of the first core is lower than the valence band of the first shell, and the conduction band of the first core is located within the band gap of the first shell; the second core-shell quantum dot includes a second core and a second shell, the conduction band of the second core is higher than the conduction band of the second shell, and the valence band of the second core is located within the band gap of the second shell; and / or, At least two of the light-emitting layers have different material configurations.

3. The optoelectronic device according to claim 2, characterized in that, The at least two light-emitting layers include at least one of a first light-emitting layer and a second light-emitting layer, and a third light-emitting layer. The first light-emitting layer is located between the third light-emitting layer and the anode, and the second light-emitting layer is located between the third light-emitting layer and the cathode, wherein: The material of the first light-emitting layer includes the first core-shell quantum dot; The material of the second light-emitting layer includes the second core-shell quantum dot; and, The material of the third light-emitting layer includes the first configuration quantum dots.

4. The optoelectronic device according to claim 2, characterized in that, The absolute value of the conduction band difference between the core and shell of the first configuration quantum dot is 0.05–1.5 eV, and the absolute value of the valence band difference between the core and shell of the first configuration quantum dot is 0.05–2.5 eV; and / or, The absolute value of the conduction band difference between the first core and the first shell is 0.5–2.0 eV, and the absolute value of the valence band difference between the first core and the first shell is 0.1–2.0 eV; and / or, The absolute value of the conduction band difference between the second core and the second shell is 0.3–1.2 eV, and the absolute value of the valence band difference between the second core and the second shell is 0.8–2.0 eV; and / or, The average particle size of the first core-shell quantum dots is 5–15 nm; and / or, The average particle size of the second core-shell quantum dot is 5–15 nm; and / or, The average particle size of the first configuration quantum dots is 5–15 nm.

5. The optoelectronic device according to claim 2, characterized in that, The materials of the first core, the first shell, the second core, the second shell, the core of the first configuration quantum dot, and the shell of the first configuration quantum dot each independently include at least one of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds; the group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, and ZnO. At least one of the following: nSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds include SnS, SnSe, SnTe, PbS, PbSe, ... At least one of PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compounds include GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, and AlNSb. At least one of AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; wherein the I-III-VI group compounds include at least one of CuInS2, CuInSe2, and AgInS2.

6. The optoelectronic device according to claim 4 or 5, characterized in that, The first core-shell quantum dot includes one or more of CdSe / ZnTe, CdSe / CdTe, and CdS / ZnSe; and / or, The second core-shell quantum dot includes one or more of CdTe / CdSe, ZnTe / ZnSe, CdTe / CdS, InP / CdSe, InP / CdS, and InAs / CdSe; and / or, The first configuration quantum dot includes one or more of CdSe / CdS, CdSe / ZnS, ZnSe / ZnS, InP / ZnSe, and InP / ZnS.

7. The optoelectronic device according to claim 3, characterized in that, The first luminescent layer includes at least one first sub-luminescent layer, wherein the material of each first sub-luminescent layer is independently selected from the first core-shell quantum dot; and / or, The second luminescent layer includes at least one second sub-luminescent layer, wherein the material of each second sub-luminescent layer is independently selected from the second core-shell quantum dot; and / or, The third light-emitting layer includes at least one third sub-light-emitting layer, and the material of each third sub-light-emitting layer is independently selected from the first configuration quantum dot.

8. The optoelectronic device according to claim 7, characterized in that, The thickness of the first sub-emitting layer is 5–15 nm; and / or, The thickness of the second sub-emitting layer is 5–15 nm; and / or, The thickness of the third sub-emissive layer is 5–15 nm.

9. The optoelectronic device according to claim 1, characterized in that, In the luminescent functional layer, the absolute value of the difference between the PL peak values ​​of any two quantum dots is less than or equal to 3 nm; and / or, The thickness of each of the light-emitting layers is 5–15 nm; and / or, The thickness of the light-emitting functional layer is 10–45 nm.

10. The optoelectronic device according to claim 1, characterized in that, The anode and the cathode each independently include a doped metal oxide particle electrode, a metal and metal oxide composite electrode, a graphene electrode, a carbon nanotube electrode, a metal electrode, or an alloy electrode. The material of the doped metal oxide particle electrode includes one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The metal and metal oxide composite electrode includes AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS. The material of the metal electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba.

11. A display device, characterized in that, Including the optoelectronic device as described in any one of claims 1 to 10.

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