Quantum dot light-emitting device and display apparatus

Abstract

Disclosed in embodiments of the present disclosure are a quantum dot light-emitting device and a display apparatus. The quantum dot light-emitting device comprises: an anode and a cathode arranged opposite to each other, a quantum dot light-emitting layer located between the anode and the cathode, a hole transport layer located between the anode and the quantum dot light-emitting layer, and an electron transport layer located between the quantum dot light-emitting layer and the cathode, wherein the hole transport layer comprises a host material and a P-type dopant; the doping concentration of the side of the P-type dopant away from the quantum dot light-emitting layer is greater than the doping concentration of the side of the P-type dopant close to the quantum dot light-emitting layer; and the doping concentration of the side of the P-type dopant close to the quantum dot light-emitting layer is greater than or equal to 0 and less than 1%.

Description

A quantum dot light-emitting device and display device Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a quantum dot light-emitting device and display apparatus. Background Technology

[0002] Quantum dots (QDs) are excellent nanomaterials for emitting light, possessing advantages such as high quantum yield, narrow emission peaks, tunable emission spectra, and high photochemical stability. Therefore, quantum dot light-emitting diodes (QLEDs), a new generation of light-emitting devices using QDs as the emitting layer, have attracted widespread attention from academia and industry due to their self-emissive nature, low power consumption, and wide color gamut.

[0003] Currently, QLED devices generally suffer from low luminous efficiency, one important factor being the imbalance between the transport of holes and electrons within the light-emitting device. Therefore, improving the balance of electron-hole transport in light-emitting devices is a problem that urgently needs to be solved in this field. Summary of the Invention

[0004] This disclosure provides a quantum dot light-emitting device and display apparatus to reduce interface quenching at the hole transport layer / quantum dot light-emitting layer, thereby improving device efficiency and brightness.

[0005] This disclosure provides a quantum dot light-emitting device, comprising: an anode and a cathode disposed opposite to each other; a quantum dot light-emitting layer located between the anode and the cathode; a hole transport layer located between the anode and the quantum dot light-emitting layer; and an electron transport layer located between the quantum dot light-emitting layer and the cathode; wherein...

[0006] The hole transport layer comprises a bulk material and a P-type dopant. The doping concentration of the P-type dopant on the side away from the quantum dot light-emitting layer is greater than the doping concentration on the side closer to the quantum dot light-emitting layer, and the doping concentration of the P-type dopant on the side closer to the quantum dot light-emitting layer is greater than or equal to 0 and less than 1%.

[0007] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the hole transport layer includes a first region and a second region stacked along the thickness direction of the hole transport layer. The first region is away from the quantum dot light-emitting layer, and the second region is close to the quantum dot light-emitting layer. The doping concentration of the P-type dopant in the first region and the second region is uniformly distributed. The doping concentration of the P-type dopant in the first region is greater than the doping concentration in the second region. The doping concentration of the P-type dopant in the second region is greater than or equal to 0 and less than 1%.

[0008] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the first region is greater than or equal to 0.8% and less than or equal to 10%.

[0009] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the thickness of the first region is greater than or equal to the thickness of the second region.

[0010] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the hole transport layer further includes a third region located between the first region and the second region. The doping concentration of the P-type dopant in the third region is uniformly distributed. The doping concentration of the P-type dopant in the third region is greater than the doping concentration in the first region, or the doping concentration of the P-type dopant in the third region is greater than the doping concentration in the second region and less than the doping concentration in the first region.

[0011] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the thickness of the first region is greater than or equal to the sum of the thicknesses of the third region and the second region.

[0012] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the sum of the thicknesses of the first region and the third region is greater than or equal to the thickness of the second region.

[0013] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the thickness of the third region is greater than the thickness of the first region and greater than the thickness of the second region.

[0014] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the hole transport layer includes a first region, a third region, and a second region stacked along the thickness direction of the hole transport layer. The first region is far from the quantum dot light-emitting layer, and the second region is close to the quantum dot light-emitting layer. The doping concentration of the P-type dopant in one or two of the first region, the third region, and the second region is uniformly distributed.

[0015] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, the doping concentration of the P-type dopant in the first region gradually increases to the doping concentration of the P-type dopant in the third region, the doping concentration of the P-type dopant in the third region is uniformly distributed, and the doping concentration of the P-type dopant in the second region gradually decreases from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer.

[0016] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, the doping concentration of the P-type dopant in the first region gradually increases to the doping concentration of the P-type dopant in the third region, the doping concentration of the P-type dopant in the third region is uniformly distributed, and the doping concentration of the P-type dopant in the second region is uniformly distributed.

[0017] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the first region is uniformly distributed, the doping concentration of the P-type dopant in the third region gradually decreases from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, and the doping concentration of the P-type dopant in the second region is uniformly distributed.

[0018] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the first region is uniformly distributed, the doping concentration of the P-type dopant in the third region gradually increases from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, and the doping concentration of the P-type dopant in the second region is uniformly distributed.

[0019] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the hole transport layer gradually decreases from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer.

[0020] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the hole transport layer decreases linearly.

[0021] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the hole transport layer is reduced in a manner that the concentration decrease rate gradually decreases.

[0022] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the hole transport layer decreases in a manner that gradually increases the rate of concentration decrease.

[0023] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the hole transport layer is Gaussian distributed from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer.

[0024] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the maximum doping concentration of the P-type dopant is located at the center of the hole transport layer, or the maximum doping concentration of the P-type dopant is located at a position away from the center of the hole transport layer on the side away from the quantum dot light-emitting layer.

[0025] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the doping concentration of the P-type dopant in the hole transport layer is parabolic, pointing from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer.

[0026] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the bulk material includes at least one, the p-type dopant in the hole transport layer includes at least one, and the bulk materials may be the same or different from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, and the materials of the p-type dopant may be the same or different.

[0027] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the P-type dopant includes at least one of halogen-containing organic small molecules and their derivatives, cyano-containing small molecules and their derivatives, nitrogen-containing heterocyclic small molecules and their derivatives, and molecules containing Lewis acid-base pairs and their derivatives.

[0028] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the P-type dopant includes at least one of F4-TCNQ, F6-TCNQ, HAT-CN, and benzoyl peroxide.

[0029] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the number of hole transport layers is greater than one, and at least one hole transport layer adopts the distribution of the P-type dopant in any of the above-described quantum dot light-emitting devices provided in the embodiments of this disclosure.

[0030] In one possible implementation, in the quantum dot light-emitting device provided in the embodiments of this disclosure, the hole transport layer includes a cross-linked network structure.

[0031] Accordingly, this disclosure also provides a display device, including the quantum dot light-emitting device described above in this disclosure. Attached Figure Description

[0032] Figure 1 is a schematic diagram of the structure of a quantum dot light-emitting device provided in an embodiment of this disclosure;

[0033] Figure 2 is a schematic diagram of one distribution of P-type dopant in the hole transport layer in Figure 1;

[0034] Figure 3 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0035] Figure 4 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0036] Figure 5 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0037] Figure 6 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0038] Figure 7 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0039] Figure 8 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0040] Figure 9 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0041] Figure 10 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0042] Figure 11 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0043] Figure 12 is another schematic diagram of the distribution of P-type dopant in the hole transport layer in Figure 1;

[0044] Figure 13 is a schematic diagram of the structure of another quantum dot light-emitting device provided in an embodiment of this disclosure;

[0045] Figure 14 shows the current-voltage curves corresponding to Comparative Example 1, Comparative Example 2, and the embodiments of this disclosure in Example 1;

[0046] Figure 15 shows the brightness-current curves corresponding to Comparative Example 2 and the embodiments of this disclosure in Example 1;

[0047] Figure 16 shows the external quantum efficiency (EQE)-current curves corresponding to Comparative Example 2 and the embodiments of this disclosure in Example 1;

[0048] Figure 17 shows the current-voltage curves corresponding to Comparative Example 1, Comparative Example 2 and the embodiments of this disclosure in Example 2;

[0049] Figure 18 shows the brightness-voltage curves corresponding to Comparative Example 1, Comparative Example 2 and the embodiments of this disclosure in Example 2;

[0050] Figure 19 shows the external quantum efficiency (EQE)-voltage curves corresponding to Comparative Example 1, Comparative Example 2 and the embodiments of this disclosure in Example 2;

[0051] Figure 20 is a schematic diagram of the structure of a display device provided in an embodiment of this disclosure. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Furthermore, the embodiments and features in the embodiments of this disclosure can be combined with each other without conflict. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0053] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "comprising" or "including," and similar terms as used in this disclosure, mean that an element or object preceding the term encompasses the elements or objects listed following the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "inner," "outer," "upper," and "lower" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0054] It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect actual proportions and are intended only to illustrate the content of this disclosure. Furthermore, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0055] Quantum dot light-emitting devices (LEDs) use quantum dot materials as the light-emitting center and rely on electron and hole transport layers to inject electrons and holes for recombination and light emission. They can be applied in display panels and lighting. In these devices, due to factors such as material properties, electron transport efficiency is often higher than hole transport efficiency, causing an imbalance in electron and hole transport. To improve the electron-hole transport balance, p-type doping is typically achieved by adding strong electron-withdrawing materials to the hole transport layer, thereby increasing the hole current and promoting carrier balance. However, the introduction of p-type dopants can cause quantum dot quenching at the interface between the hole transport layer and the quantum dot light-emitting layer, leading to a decrease in the device's luminous efficiency.

[0056] In view of this, in order to improve the luminous efficiency of QLED light-emitting devices, this disclosure provides a quantum dot light-emitting device, as shown in FIG1, including: an anode 1 and a cathode 2 disposed opposite to each other, a quantum dot light-emitting layer 3 located between the anode 1 and the cathode 2, a hole transport layer 4 located between the anode 1 and the quantum dot light-emitting layer 3, and an electron transport layer 5 located between the quantum dot light-emitting layer 3 and the cathode 2; wherein,

[0057] The hole transport layer 4 includes a bulk material and a P-type dopant. The doping concentration of the P-type dopant on the side away from the quantum dot light-emitting layer 3 is greater than the doping concentration on the side closer to the quantum dot light-emitting layer 3, and the doping concentration of the P-type dopant on the side closer to the quantum dot light-emitting layer 3 is greater than or equal to 0 and less than 1%.

[0058] The quantum dot light-emitting device provided in this disclosure improves hole concentration and promotes carrier balance by adding a P-type dopant with strong electron-withdrawing ability to the hole transport layer, thereby compensating for the negative impact of low hole mobility. Furthermore, by adjusting the distribution of the P-type dopant in the hole transport layer, hole injection can be regulated. Since the doping concentration of the P-type dopant near the quantum dot light-emitting layer is greater than or equal to 0 and less than 1%, the low or even zero doping concentration near the quantum dot light-emitting layer reduces quantum dot quenching at the hole transport layer / quantum dot light-emitting layer interface caused by the strong electron-withdrawing groups in the P-type dopant, thus improving device brightness. Additionally, the variation in P-type dopant concentration in the hole transport layer creates a carrier concentration gradient, which diffuses to form a built-in electric field, regulating hole injection into the quantum dot light-emitting layer, further promoting carrier balance, and ultimately improving device efficiency. Therefore, this disclosure significantly regulates hole injection and light-emitting properties by optimizing the distribution of the P-type dopant in the hole transport layer.

[0059] In some embodiments, the quantum dot light-emitting device provided in this disclosure is shown in Figures 2 and 3. Figures 2 and 3 only illustrate the three-layer structure of hole transport layer 4, quantum dot light-emitting layer 3, and electron transport layer 5 in Figure 1. The hole transport layer 4 includes a first region A1 and a second region A2 stacked along the thickness direction of the hole transport layer 4. The first region A1 is far away from the quantum dot light-emitting layer 3, and the second region A2 is close to the quantum dot light-emitting layer 3. The doping concentration of P-type dopant p in the first region A1 and the second region A2 is uniformly distributed. The doping concentration of P-type dopant p in the first region A1 is greater than the doping concentration in the second region A2. The doping concentration of P-type dopant p in the second region A2 is greater than or equal to 0 and less than 1%, and the doping concentration of P-type dopant p in the first region A1 is greater than or equal to 0.8% and less than or equal to 10%. This allows for optimal doping concentration in the second region A2, improving hole transport efficiency and enhancing the overall luminous efficiency of the device. Furthermore, the lower doping concentration in the first region A1, which is closer to the quantum dot emitting layer 3, reduces quantum dot quenching at the interface between the hole transport layer 4 and the quantum dot emitting layer 3, thus improving device brightness. Additionally, the presence of a carrier concentration gradient between the first region A1 and the second region A2 allows for carrier diffusion, forming a built-in electric field that regulates hole injection into the quantum dot emitting layer 3, further promoting carrier balance and ultimately improving device efficiency.

[0060] In some embodiments, as shown in FIG2, the doping concentration of P-type dopant p in the first region A1 can be 1%, and the doping concentration of P-type dopant p in the second region A2 can be 0.

[0061] In some embodiments, as shown in FIG3, the doping concentration of P-type dopant p in the first region A1 can be 5%, and the doping concentration of P-type dopant p in the second region A2 can be 0.1%.

[0062] It should be noted that Figures 2 and 3 are merely illustrative examples of the doping concentration of P-type dopant p in the first region A1 and the second region A2.

[0063] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in Figures 2 and 3, the thickness of the first region A1 is greater than or equal to the thickness of the second region A2. This causes the doping concentration variation node of the P-type dopant p in the first region A1 and the second region A2 to be located at half the thickness of the hole transport layer 4 or near the side of the quantum dot light-emitting layer 3, further improving the hole transport efficiency.

[0064] In some embodiments, as shown in FIG2 and FIG3, the bulk materials in the first region A1 and the second region A2 can be the same material or different materials.

[0065] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in FIG3, the P-type dopant p in the first region A1 and the second region A2 can be the same material or different materials.

[0066] In some embodiments, as shown in FIG4, the hole transport layer 4 further includes a third region A3 located between the first region A1 and the second region A2. The doping concentration of P-type dopant p in the third region A3 is uniformly distributed. The doping concentration of P-type dopant p in the third region A3 is greater than that in the first region A1. Since the doping concentration of P-type dopant p in the first region A1 is greater than that in the second region A2, the doping concentration of P-type dopant p first increases and then decreases from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3. The P-type dopant p is abruptly distributed in the hole transport layer 4, containing two abrupt change nodes. The interface between the first region A1 and the third region A3 is the first abrupt change node, and the interface between the third region A3 and the second region A2 is the second abrupt change node. For example, the doping concentration of P-type dopant p in the first region A1 is 2%, the doping concentration of P-type dopant p in the third region A3 is 5%, and the doping concentration of P-type dopant p in the second region A2 is 0.1%. This can optimize the distribution of P-type dopant p in the hole transport layer 4, which has a great regulating effect on the hole injection and light emission properties of the control device.

[0067] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in FIG4, the doping concentration of P-type dopant p in the first region A1 is greater than or equal to 1% and less than or equal to 5%, the doping concentration of P-type dopant p in the third region A3 is greater than 5% and less than or equal to 10%, and the doping concentration of P-type dopant p in the second region A1 is greater than or equal to 0 and less than 1%.

[0068] In some embodiments, as shown in FIG5, the hole transport layer 4 further includes a third region A3 located between the first region A1 and the second region A2. The doping concentration of P-type dopant p in the third region A3 is uniformly distributed. The doping concentration of P-type dopant p in the third region A3 is greater than that in the second region A2 and less than that in the first region A1. That is, from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the doping concentration of P-type dopant p gradually decreases. The P-type dopant p in the hole transport layer 4 is abruptly distributed, containing two abrupt change nodes. The interface between the first region A1 and the third region A3 is the first abrupt change node, and the interface between the third region A3 and the second region A2 is the second abrupt change node. For example, the doping concentration of P-type dopant p in the first region A1 is 10%, the doping concentration of P-type dopant p in the third region A3 is 2%, and the doping concentration of P-type dopant p in the second region A2 is 0.1%. This can optimize the distribution of P-type dopant p in the hole transport layer 4, which has a great regulating effect on the hole injection and light emission properties of the control device.

[0069] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in FIG5, the doping concentration of P-type dopant p in the first region A1 is greater than or equal to 5% and less than or equal to 10%, the doping concentration of P-type dopant p in the third region A3 is greater than or equal to 1% and less than 5%, and the doping concentration of P-type dopant p in the second region A1 is greater than or equal to 0 and less than 1%.

[0070] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in Figures 4 and 5, the thickness of the first region A1 can be greater than or equal to the sum of the thicknesses of the third region A3 and the second region A2. In this way, the first mutation node is located at half the thickness of the hole transport layer 4, or the first mutation node is located close to the quantum dot light-emitting layer 3, which is beneficial to improving the hole transport efficiency.

[0071] In some embodiments, as shown in FIG4 and FIG5, in the quantum dot light-emitting device provided in the present disclosure, the sum of the thicknesses of the first region A1 and the third region A3 may be greater than or equal to the thickness of the second region A2, or the thickness of the third region A3 may be greater than the thickness of the first region A1 and greater than the thickness of the second region A2. The thicknesses of the first region A1, the third region A3 and the second region A2 are designed according to the hole transport efficiency requirements.

[0072] In some embodiments, as shown in FIG4 and FIG5, the bulk materials in the first region A1, the third region A3 and the second region A2 can be the same material or different materials.

[0073] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in Figures 4 and 5, the P-type dopant p in the first region A1, the third region A3, and the second region A2 can be the same material or different materials.

[0074] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, as shown in Figures 6-9, the hole transport layer 4 includes a first region A1, a third region A3, and a second region A2 stacked along the thickness direction of the hole transport layer 4. The first region A1 is far from the quantum dot light-emitting layer 3, and the second region A2 is close to the quantum dot light-emitting layer 3. The doping concentration of P-type dopant p in one or two of the first region A1, the third region A3, and the second region A2 is uniformly distributed. For example, the doping concentration of P-type dopant p in the first region A1 is greater than that in the second region A2, and the doping concentration of P-type dopant p in the third region A3 is greater than that in the second region A2. That is, the doping concentration of P-type dopant p in the hole transport layer 4 first increases and then decreases. In this way, this embodiment can optimize the distribution of P-type dopant p in the hole transport layer 4, which has a significant regulating effect on the hole injection and light emission properties of the device.

[0075] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in FIG6, from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the doping concentration of P-type dopant p in the first region A1 gradually increases to the doping concentration of P-type dopant in the third region A3, and the doping concentration of P-type dopant p in the third region A3 is uniformly distributed. The doping concentration of P-type dopant p in the second region A2 gradually decreases from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3. For example, the doping concentration of P-type dopant in the first region A1 away from the quantum dot light-emitting layer 3 is 1%, and the doping concentration in the first region A1 gradually increases to 10% from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3. The P-type dopant p in the third region A3 is uniformly distributed and has a doping concentration of 10%. The doping concentration of P-type dopant p in the second region A2 gradually decreases from 10% to 0% from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3.

[0076] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, as shown in FIG7, from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the doping concentration of P-type dopant p in the first region A1 gradually increases to the doping concentration of P-type dopant p in the third region A3, the doping concentration of P-type dopant p in the third region A3 is uniformly distributed, and the doping concentration of P-type dopant p in the second region A2 is uniformly distributed. For example, the doping concentration of P-type dopant in the first region A1 away from the quantum dot light-emitting layer 3 is 1%, the doping concentration in the first region A1 gradually increases to 10% from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the P-type dopant p is uniformly distributed and the doping concentration is 10% in the third region A3, and the doping concentration of P-type dopant p in the second region A2 is 0.1%.

[0077] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, as shown in FIG8, the doping concentration of P-type dopant p is uniformly distributed in the first region A1, the doping concentration of P-type dopant p in the third region A3 gradually decreases from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, and the doping concentration of P-type dopant p is uniformly distributed in the second region A2. For example, the doping concentration of P-type dopant in the first region A1 is 1%, the doping concentration in the third region A3 gradually decreases from 10% to 0.1% from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, and the doping concentration of P-type dopant p in the second region A2 is 0.1%.

[0078] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, as shown in FIG9, the doping concentration of P-type dopant p is uniformly distributed in the first region A1, the doping concentration of P-type dopant p in the third region A3 gradually increases from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, and the doping concentration of P-type dopant p is uniformly distributed in the second region A2. For example, the doping concentration of P-type dopant in the first region A1 is 1%, the doping concentration in the third region A3 gradually increases from 1% to 10% from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, and the doping concentration of P-type dopant p in the second region A2 is 0.1%.

[0079] It should be noted that the doping concentration of P-type dopant p in each region of hole transport layer 4 in Figures 6-9 is only for illustrative purposes. As long as the doping concentration of P-type dopant p in each region conforms to the concentration doping rule, it is acceptable.

[0080] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, as shown in Figures 10-12, the doping concentration of P-type dopant p in the hole transport layer 4 can be gradually reduced from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3. For example, the doping concentration of P-type dopant on the side away from the quantum dot light-emitting layer 3 is 1%, and the doping concentration of P-type dopant p on the side closer to the quantum dot light-emitting layer 3 is 0%, thus reducing the doping concentration of P-type dopant p from 1% to 0%. In this way, this embodiment can optimize the distribution of P-type dopant in the hole transport layer 4, which has a significant regulating effect on the hole injection and light emission properties of the device.

[0081] In some embodiments of the quantum dot light-emitting device provided in this disclosure, as shown in FIG10, the doping concentration of the p-type dopant p in the hole transport layer 4 can be linearly reduced. For example, from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the doping concentrations are 1%, 0.8%, 0.6%, 0.4%, 0.2%, and 0% respectively.

[0082] In some embodiments of the quantum dot light-emitting device provided in this disclosure, as shown in FIG11, the doping concentration of the P-type dopant p in the hole transport layer 4 decreases gradually at a decreasing rate. For example, from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the doping concentrations are 1%, 0.6%, 0.3%, 0.1%, and 0% respectively.

[0083] In some embodiments of the quantum dot light-emitting device provided in this disclosure, as shown in FIG12, the doping concentration of the p-type dopant p in the hole transport layer 4 decreases in a manner that gradually increases the rate of concentration decrease. For example, from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, the doping concentrations are 1%, 0.9%, 0.7%, 0.4%, and 0% respectively.

[0084] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, the doping concentration of the P-type dopant in the hole transport layer can also exhibit a Gaussian distribution, from the side furthest from the quantum dot light-emitting layer to the side closest to the quantum dot light-emitting layer. That is, the doping concentration of the P-type dopant varies according to the slope of a Gaussian distribution curve. The maximum doping concentration of the P-type dopant can be located at the center of the hole transport layer, or the maximum doping concentration of the P-type dopant can be located at the center of the hole transport layer on the side furthest from the quantum dot light-emitting layer. In this way, this embodiment can optimize the distribution of the P-type dopant in the hole transport layer 4, which has a significant regulatory effect on the hole injection and light-emitting properties of the device.

[0085] It should be noted that the Gaussian distribution of the doping concentration of P-type dopant in the hole transport layer refers to an approximate Gaussian distribution.

[0086] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, the doping concentration of the P-type dopant in the hole transport layer can also exhibit a parabolic distribution from the side furthest from the quantum dot light-emitting layer to the side closest to the quantum dot light-emitting layer. For example, the doping concentration of the P-type dopant on the side furthest from the quantum dot light-emitting layer is 1%, the doping concentration of the P-type dopant on the side closest to the quantum dot light-emitting layer is 0%, and the highest intermediate doping concentration between 1% and 0% is 10%. The doping concentration of the P-type dopant first increases and then decreases from the side furthest from the quantum dot light-emitting layer to the side closest to the quantum dot light-emitting layer, exhibiting a parabolic distribution. In this way, this embodiment can optimize the distribution of the P-type dopant in the hole transport layer 4, which has a significant regulatory effect on the hole injection and light emission properties of the control device.

[0087] It should be noted that the parabolic distribution of the doping concentration of P-type dopant in the hole transport layer refers to an approximate parabolic distribution.

[0088] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, as shown in Figures 1-12, the bulk material in the hole transport layer 4 includes at least one type, and the P-type dopant p in the hole transport layer 4 includes at least one type. The bulk materials are the same or different from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3, and the materials of the P-type dopant p are the same or different.

[0089] In some embodiments, in the quantum dot light-emitting devices provided in the embodiments of this disclosure, the bulk material of the hole transport layer may include organic or inorganic hole transport materials, such as poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (abbreviated as TFB), poly(N-vinylcarbazole) (abbreviated as PVK), and at least one of poly(4-phenyl)(4-butylphenyl)amine] (abbreviated as Poly-TPD), poly((9,9-dioctylfluorene-2,7-diyl)-alt-(9-(2-ethylhexyl)-carbazole-3,6-diyl) (abbreviated as PF8Cz), NPD, CBP, MoOx, and NiOx, which are not limited in this disclosure.

[0090] In some embodiments, in the quantum dot light-emitting devices provided in this disclosure, the P-type dopant includes at least one of the following: halogen-containing organic small molecules and their derivatives, cyano-containing small molecules and their derivatives, nitrogen-containing heterocyclic small molecules and their derivatives, and molecules containing Lewis acid-base pairs and their derivatives. Of course, the P-type dopant may also include other materials with strong electron-withdrawing capabilities.

[0091] In some embodiments, the P-type dopant in the quantum dot light-emitting device provided in the present disclosure includes at least one of 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (abbreviated as F4-TCNQ), 2,2'-(perfluoronaphthalene-2,6-diylidene)dipropylenedicyano (abbreviated as F6-TCNQ), bispyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexanonitrile (abbreviated as HAT-CN), and benzoyl peroxide (C6H5C(=O)OO-OC(=O)C6H5).

[0092] In some embodiments, in the quantum dot light-emitting devices provided in the embodiments of this disclosure, Figures 1-12 all take the hole transport layer 4 as an example. Of course, the number of hole transport layers 4 can be greater than one, such as two layers, three layers, etc. At least one hole transport layer adopts the distribution of P-type dopant in the above embodiments.

[0093] In some embodiments of the quantum dot light-emitting device provided in this disclosure, as shown in Figures 1-12, the hole transport layer 4 may include a cross-linked network structure. This allows the hole transport layer to be made of a cross-linkable material, and the quantum dot material to be cross-linkable, thus serving as a sacrificial layer to prevent crosstalk caused by quantum dot residue. Furthermore, the cross-linked network structure of the hole transport layer prevents solvent dissolution of the hole transport layer during subsequent film fabrication, improving its stability. However, in quantum dot light-emitting devices, cross-linking of the hole transport layer reduces its mobility, leading to a decrease in hole current density and consequently reducing device brightness. Therefore, this embodiment of the invention, by adding a P-type dopant with strong electron-withdrawing ability to the hole transport layer, can increase the hole concentration and promote carrier balance, thereby compensating for the negative impact of the low mobility of the hole transport layer. Furthermore, by adjusting the distribution of the P-type dopant in the hole transport layer, hole injection can be regulated. Since the doping concentration of the P-type dopant near the quantum dot emitting layer is greater than or equal to 0 and less than 1%, the doping concentration of the P-type dopant near the quantum dot emitting layer is low, even zero. This reduces the quenching of quantum dots at the hole transport layer / quantum dot emitting layer interface caused by the strong electron-withdrawing groups in the P-type dopant, improving device brightness. On the other hand, the variation in P-type dopant concentration in the hole transport layer creates a carrier concentration gradient, which in turn allows carrier diffusion to form a built-in electric field, regulating hole injection into the quantum dot emitting layer, further promoting carrier balance, and ultimately improving device efficiency. Therefore, this invention, by optimizing the distribution of the P-type dopant in the hole transport layer, has a significant regulatory effect on the hole injection and luminescence properties of the device.

[0094] Alternatively, the hole transport layer in the embodiments of this disclosure may also be an uncrosslinked structure.

[0095] In some embodiments, the quantum dot light-emitting device provided in the present disclosure can be prepared by methods such as spin coating, blade coating, and inkjet printing to form a hole injection layer, a hole transport layer, and an electron transport layer. The p-type dopant can be mixed in the hole transport material and then the hole transport layer can be prepared.

[0096] In some embodiments, as shown in FIG1, the quantum dot light-emitting device provided in this disclosure can be an upright structure. The quantum dot light-emitting device further includes a substrate 6 located on the side of the anode 1 away from the quantum dot light-emitting layer 3 and a hole injection layer 7 located between the anode 1 and the hole transport layer 4. The substrate 6 can be a rigid substrate or a flexible substrate. The rigid substrate can be a glass substrate or a PMMA (polymethyl methacrylate) substrate, and the flexible substrate can be a PET (polyethylene terephthalate) substrate or a PI (polyimide) substrate.

[0097] In some embodiments, the quantum dot light-emitting device provided in the present disclosure can also be an inverted structure, as shown in FIG13. The difference between the inverted structure and the upright structure is that the film layer fabrication order is different, but the distribution of P-type dopant in the hole transport layer 4 is the same as that in the upright structure.

[0098] In some embodiments, in the quantum dot light-emitting device provided in the present disclosure, the anode material can be ITO or the cathode material can be Al or the like.

[0099] In some embodiments, in the quantum dot light-emitting devices provided in the embodiments of this disclosure, the material of the hole injection layer can be PEDOT, NiOx, MoOx, WOx, V2O5, CuSCN, etc., and this disclosure does not limit it.

[0100] In some embodiments, the material of the electron transport layer in the quantum dot light-emitting device provided in the present disclosure can be nanoparticles such as ZnO and ZnMgO, and the present disclosure does not limit this.

[0101] In some embodiments, in the quantum dot light-emitting device provided in this disclosure, the quantum dot light-emitting layer includes a quantum dot material (QD). The quantum dot material includes a quantum dot body and ligands coordinated and connected to the surface of the quantum dot body. The quantum dot body includes, but is not limited to, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgSe, HgTe, HgS, and Hg x Cd 1-x Te, Hg x Cd1-x S, Hg x Cd 1-x Se, Hg x Zn 1-x Te, Cd x Zn 1-x Se, or Cd x Zn 1-x S, InP, InAs, InSb, GaAs, GaP, GaN, GaSb, InN, InSb, AlP, AlN, AlAs, PbS, PbSe, PbTe, CdSe@ZnS, CdSe@CdS, InP@ZnS, CdTe@CdSe, CdSe@ZnTe, ZnTe@CdSe, ZnSe@CdS or Cd 1-x Zn x S@ZnS, where 0 <x<1。

[0102] The distribution of P-type dopant in the hole transport layer and the obtained electrical performance in the quantum dot light-emitting device provided in this disclosure will be described below with specific embodiments.

[0103] Example 1: Control of doping concentration of P-type dopant in hole transport layer of blue quantum dot light-emitting device.

[0104] The device structure is shown in Figures 1 and 2. The hole transport layer 4 is made of PF8Cz and has a cross-linked network structure. The total thickness of the hole transport layer 4 is 22 nm. The hole transport layer 4 has a first region A1 with P-type dopant p that is far away from the quantum dot light-emitting layer 3. The thickness of the first region A1 is 20 nm. The doping concentration of the P-type dopant p is 1%. The material of the P-type dopant p is F4-TCNQ. The second region A2, which is close to the quantum dot light-emitting layer 3, has no P-type dopant p. The thickness of the second region A2 is 2 nm. The interface between the first region A1 and the second region A2 is abrupt. The hole injection layer 7, the hole transport layer 4, the quantum dot light-emitting layer 3, and the electron transport layer 5 are prepared by spin coating. The anode 1 is prepared by magnetron sputtering. The cathode 2 is prepared by vapor deposition.

[0105] Method for adding P-type dopant to hole transport materials: Mix hole transport material PF8Cz and P-type dopant F4-TCNQ in chlorobenzene in a certain proportion and dissolve.

[0106] Comparative Example 1: No P-type dopant in the hole transport layer

[0107] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / PF8Cz (22nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0108] Comparative Example 2: The hole transport layer is uniformly distributed with P-type dopant F4-TCNQ at a doping concentration of 1%.

[0109] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / PF8Cz-F4-TCNQ (1%) (22nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0110] This disclosure embodiment adopts the structures described in Figures 1 and 2 above.

[0111] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / PF8Cz-F4-TCNQ (1%) (20nm) / PF8Cz (2nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0112] As shown in Figure 14, which is the current-voltage curve corresponding to Comparative Example 1, Comparative Example 2 and the embodiment of this disclosure, it can be seen that the current in the embodiment of this disclosure is greater than the current in Comparative Example 1 and less than the current in Comparative Example 2, proving that the P-type dopant proposed in the embodiment of this disclosure for regulating the hole transport layer has the effect of regulating the device current.

[0113] As shown in Figures 15 and 16, Figure 15 shows the brightness-current curves corresponding to Comparative Example 2 and the embodiments of this disclosure, and Figure 16 shows the external quantum efficiency (EQE)-current curves corresponding to Comparative Example 2 and the embodiments of this disclosure. It can be seen that, under the same current, compared with the case of P-type dopant being distributed throughout the hole transport layer in Comparative Example 2, the brightness and external quantum efficiency of the device in the embodiments of this disclosure are significantly improved, proving that the device structure of this disclosure reduces interface quenching at the hole transport layer / quantum dot light-emitting layer.

[0114] Example 2: Control of doping concentration of P-type dopant in hole transport layer of green quantum dot light-emitting device.

[0115] The difference between this embodiment and Embodiment 1 is that the quantum dot light-emitting layer 3 emits green light, the hole transport layer 4 is made of TFB material, the total thickness of the hole transport layer 4 is 23nm, the thickness of the first region A1 is 20nm, and the thickness of the second region A2 is 3nm.

[0116] Comparative Example 1: No P-type dopant in the hole transport layer

[0117] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB (23nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0118] Comparative Example 2: The hole transport layer is uniformly distributed with P-type dopant F4-TCNQ at a doping concentration of 1%.

[0119] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F4-TCNQ (1%) (23nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0120] Example: As described above

[0121] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F4-TCNQ (1%) (20nm) / TFB (3nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0122] As shown in Figures 17-19, Figure 17 shows the current-voltage curves corresponding to Comparative Examples 1, 2, and the embodiments of this disclosure; Figure 18 shows the brightness-voltage curves corresponding to Comparative Examples 1, 2, and the embodiments of this disclosure; and Figure 19 shows the external quantum efficiency (EQE)-voltage curves corresponding to Comparative Examples 1, 2, and the embodiments of this disclosure. It can be seen that the current in the embodiments of this disclosure is greater than that in Comparative Example 1 but less than that in Comparative Example 2, proving that the P-type dopant proposed in the embodiments of this disclosure for regulating the hole transport layer effectively regulates the device current. Figure 18 shows that the device brightness in the embodiments of this disclosure is greater than that in Comparative Example 1, indicating that current regulation improves device efficiency (Figure 19). The device brightness in the embodiments of this disclosure is greater than that in Comparative Example 2, indicating that the quenching caused by the P-type dopant at the hole transport layer / quantum dot emitting layer interface is reduced. The structure of the embodiments of this disclosure effectively reduces interface quenching at the hole transport layer / quantum dot emitting layer.

[0123] Example 3:

[0124] The difference from Example 2 is that the material of the P-type dopant is F6-TCNQ.

[0125] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F6-TCNQ (1%) (20nm) / TFB (3nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0126] Example 4:

[0127] The difference from Example 2 is that the material of the P-type dopant is HAT-CN.

[0128] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F6-HAT-CN (1%) (20nm) / TFB (3nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0129] It should be noted that the electrical performance of Embodiments 3 and 4 is the same as that of Embodiment 2.

[0130] Example 5:

[0131] The doping concentration distribution of the P-type dopant p in the hole transport layer 4 adopts the structure shown in Figure 10. The material of the hole transport layer 4 is TFB and cross-linked, and the material of the P-type dopant p is F4-TCNQ. The doping concentration decreases linearly from 10% to 0 from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3.

[0132] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F4-TCNQ (10-0%) (23nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0133] By taking advantage of the difference in solubility between the hole transport layer and the P-type dopant, the P-type dopant precipitates out of the solution before the hole transport layer during the solution preparation process, thus forming a doping concentration that decreases from the side away from the quantum dot light-emitting layer 3 to the side closer to the quantum dot light-emitting layer 3.

[0134] Example 6:

[0135] Using the structure shown in Figure 2, the hole transport layer 4 is made of TFB+PF8Cz and is cross-linked. The p-type dopant p is F6-TCNQ with a doping concentration of 1%. The thickness of the first region A1 is 20 nm and the thickness of the second region A2 is 3 nm.

[0136] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-PF8Cz-F6-TCNQ (1%) (20nm) / TFB-PF8Cz (3nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0137] Example 7:

[0138] The inverted structure shown in Figure 13 is adopted. The hole transport layer 4 is made of TFB and cross-linked. The P-type dopant is F4TCNQ with a doping concentration of 1%. The thickness of the first region A1, which is far away from the quantum dot light-emitting layer 3, is 20 nm, and the thickness of the second region A2, which is close to the quantum dot light-emitting layer 3, is 3 nm.

[0139] Device structure: ITO (100nm) / ZnMgO (60nm) / QD (20nm) / TFB (3nm) / TFB-F4-TCNQ (1%) (20nm) / PEDOT:PSS (25nm) / Ag (100nm)

[0140] Example 8:

[0141] Using the doping distribution shown in Figure 3, the hole transport layer 4 has a cross-linked network structure. The hole transport materials of the first region A1 and the second region A2 are different, and the P-type dopants are different. For example, the hole transport material of the first region A1 is TFB and the P-type dopant is F4-TCNQ, while the hole transport material of the second region A2 is PF8Cz and the P-type dopant is HATCN.

[0142] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F4-TCNQ (10%) (20nm) / PF8Cz-HAT-CN (1%) (3nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0143] Example 9:

[0144] Using the doping distribution structure shown in Figure 3, the hole transport layer 4 has a cross-linked network structure. The material of the hole transport layer 4 is TFB, and the p-type dopants of the first region A1 and the second region A2 are different. For example, the thickness of the first region A1 is 20 nm, the p-type dopant of the first region A1 is F4-TCNQ, and the doping concentration is 1%. The thickness of the second region A2 is 3 nm, the p-type dopant of the second region A2 is HATCN, and the doping concentration is 0.1%.

[0145] Device structure: ITO (100nm) / PEDOT:PSS (25nm) / TFB-F4-TCNQ (1%) (20nm) / TFB-HAT-CN (0.1%) (3nm) / QD (20nm) / ZnMgO (60nm) / Al (100nm)

[0146] It should be noted that the electrical performance of Examples 5-9 is basically the same as that of Example 2.

[0147] In some embodiments, the quantum dot light-emitting device provided in this disclosure may be a quantum dot light-emitting diode.

[0148] In some embodiments, the light emission mode of the quantum dot light-emitting device provided in this disclosure can be bottom light emission or top light emission.

[0149] In some embodiments, the light-emitting device provided in this disclosure may also include other functional film layers well known to those skilled in the art, which will not be described in detail here.

[0150] Based on the same inventive concept, this disclosure also provides a display device, including the quantum dot light-emitting device described above. Since the principle by which this display device solves the problem is similar to that of the quantum dot light-emitting device, the implementation of the display device provided in this disclosure can refer to the implementation of the quantum dot light-emitting device, and repeated details will not be elaborated further.

[0151] In specific implementation, the display device provided in the embodiments of this disclosure can be an organic light-emitting display device.

[0152] In specific implementation, the display device provided in the embodiments of this disclosure may be a full-screen display device or a flexible display device, etc., and is not limited thereto.

[0153] In specific implementations, the display device provided in this disclosure embodiment can be a full-screen mobile phone as shown in FIG20. Of course, the display device provided in this disclosure embodiment can also be any product or component with display function, such as a tablet computer, television, monitor, laptop computer, digital photo frame, or navigator. Other essential components of this display device are understood by those skilled in the art and will not be described in detail here, nor should they be construed as limitations on this disclosure. This display device includes, but is not limited to, components such as: a radio frequency unit, a network module, an audio output & input unit, a sensor, a display unit, a user input unit, an interface unit, a memory, a processor, and a power supply. Furthermore, those skilled in the art will understand that the above structure does not constitute a limitation on the display device provided in this disclosure embodiment. In other words, the display device provided in this disclosure embodiment can include more or fewer of the above components, or combine certain components, or have different component arrangements.

[0154] This disclosure provides a quantum dot light-emitting device and display apparatus. By adding a P-type dopant with strong electron-withdrawing ability to the hole transport layer, the hole concentration can be increased, promoting carrier balance and thus compensating for the negative impact of low hole mobility in the hole transport layer. Furthermore, by adjusting the distribution of the P-type dopant in the hole transport layer, hole injection can be regulated. Since the doping concentration of the P-type dopant near the quantum dot light-emitting layer is greater than or equal to 0 and less than 1%, the doping concentration of the P-type dopant near the quantum dot light-emitting layer is low or even zero. On the one hand, this reduces the quenching of quantum dots at the hole transport layer / quantum dot light-emitting layer interface caused by the strong electron-withdrawing groups in the P-type dopant, improving device brightness. On the other hand, the variation in the P-type dopant concentration in the hole transport layer creates a carrier concentration gradient, which in turn allows carrier diffusion to form a built-in electric field, regulating hole injection into the quantum dot light-emitting layer, further promoting carrier balance in the device, and ultimately improving device efficiency. Therefore, this disclosure has a significant regulatory effect on the hole injection and light-emitting properties of the device by optimizing the distribution of the P-type dopant in the hole transport layer.

[0155] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0156] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A quantum dot light-emitting device, wherein, include: An anode and cathode are disposed opposite to each other; a quantum dot light-emitting layer is located between the anode and the cathode; a hole transport layer is located between the anode and the quantum dot light-emitting layer; and an electron transport layer is located between the quantum dot light-emitting layer and the cathode. The hole transport layer comprises a bulk material and a P-type dopant. The doping concentration of the P-type dopant on the side away from the quantum dot light-emitting layer is greater than the doping concentration on the side closer to the quantum dot light-emitting layer, and the doping concentration of the P-type dopant on the side closer to the quantum dot light-emitting layer is greater than or equal to 0 and less than 1%.

2. The quantum dot light-emitting device as described in claim 1, wherein, The hole transport layer includes a first region and a second region stacked along the thickness direction of the hole transport layer. The first region is far from the quantum dot light-emitting layer, and the second region is close to the quantum dot light-emitting layer. The doping concentration of the P-type dopant in the first region and the second region is uniformly distributed. The doping concentration of the P-type dopant in the first region is greater than the doping concentration in the second region. The doping concentration of the P-type dopant in the second region is greater than or equal to 0 and less than 1%.

3. The quantum dot light-emitting device as described in claim 2, wherein, The doping concentration of the P-type dopant in the first region is greater than or equal to 0.8% and less than or equal to 10%.

4. The quantum dot light-emitting device as described in claim 3, wherein, The thickness of the first region is greater than or equal to the thickness of the second region.

5. The quantum dot light-emitting device as described in claim 2, wherein, The hole transport layer further includes a third region located between the first region and the second region, wherein the doping concentration of the P-type dopant in the third region is uniformly distributed, and the doping concentration of the P-type dopant in the third region is greater than the doping concentration in the first region, or the doping concentration of the P-type dopant in the third region is greater than the doping concentration in the second region but less than the doping concentration in the first region.

6. The quantum dot light-emitting device as described in claim 5, wherein, The thickness of the first region is greater than or equal to the sum of the thicknesses of the third region and the second region.

7. The quantum dot light-emitting device as described in claim 5, wherein, The sum of the thicknesses of the first region and the third region is greater than or equal to the thickness of the second region.

8. The quantum dot light-emitting device as described in claim 5, wherein, The thickness of the third region is greater than the thickness of the first region and greater than the thickness of the second region.

9. The quantum dot light-emitting device as described in claim 1, wherein, The hole transport layer includes a first region, a third region, and a second region stacked along the thickness direction of the hole transport layer. The first region is far from the quantum dot light-emitting layer, and the second region is close to the quantum dot light-emitting layer. The doping concentration of the P-type dopant is uniformly distributed in one or two of the first region, the third region, and the second region.

10. The quantum dot light-emitting device as described in claim 9, wherein, From the side furthest from the quantum dot light-emitting layer toward the side closer to the quantum dot light-emitting layer, the doping concentration of the P-type dopant in the first region gradually increases to the doping concentration of the P-type dopant in the third region, where the doping concentration of the P-type dopant is uniformly distributed. In the second region, the doping concentration of the P-type dopant gradually decreases from the side furthest from the quantum dot light-emitting layer toward the side closer to the quantum dot light-emitting layer.

11. The quantum dot light-emitting device as described in claim 9, wherein, From the side furthest from the quantum dot light-emitting layer toward the side closer to the quantum dot light-emitting layer, the doping concentration of the P-type dopant in the first region gradually increases to the doping concentration of the P-type dopant in the third region, the doping concentration of the P-type dopant in the third region is uniformly distributed, and the doping concentration of the P-type dopant in the second region is uniformly distributed.

12. The quantum dot light-emitting device as described in claim 9, wherein, The doping concentration of the P-type dopant is uniformly distributed in the first region, the doping concentration of the P-type dopant in the third region gradually decreases from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, and the doping concentration of the P-type dopant is uniformly distributed in the second region.

13. The quantum dot light-emitting device as described in claim 9, wherein, The doping concentration of the P-type dopant is uniformly distributed in the first region, the doping concentration of the P-type dopant in the third region gradually increases from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer, and the doping concentration of the P-type dopant is uniformly distributed in the second region.

14. The quantum dot light-emitting device as described in claim 1, wherein, From the side furthest from the quantum dot emitting layer toward the side closer to the quantum dot emitting layer, the doping concentration of the P-type dopant in the hole transport layer gradually decreases.

15. The quantum dot light-emitting device as described in claim 14, wherein, The doping concentration of the P-type dopant within the hole transport layer decreases linearly.

16. The quantum dot light-emitting device as described in claim 14, wherein, The doping concentration of the P-type dopant within the hole transport layer decreases gradually at a decreasing rate.

17. The quantum dot light-emitting device as described in claim 14, wherein, The doping concentration of the P-type dopant within the hole transport layer decreases gradually at an increasing rate of concentration decrease.

18. The quantum dot light-emitting device as claimed in claim 1, wherein, From the side furthest from the quantum dot emitting layer to the side closest to the quantum dot emitting layer, the doping concentration of the P-type dopant in the hole transport layer exhibits a Gaussian distribution.

19. The quantum dot light-emitting device as described in claim 18, wherein, The maximum doping concentration of the P-type dopant is located at the center of the hole transport layer, or the maximum doping concentration of the P-type dopant is located on the side of the hole transport layer away from the quantum dot light-emitting layer.

20. The quantum dot light-emitting device as claimed in claim 1, wherein, From the side furthest from the quantum dot emitting layer to the side closest to the quantum dot emitting layer, the doping concentration of the P-type dopant in the hole transport layer exhibits a parabolic distribution.

21. The quantum dot light-emitting device according to any one of claims 1-20, wherein, The bulk material includes at least one, and the p-type dopant in the hole transport layer includes at least one, and the dopant is distributed from the side away from the quantum dot light-emitting layer to the side closer to the quantum dot light-emitting layer. The bulk materials may be the same or different, and the p-type dopant materials may be the same or different.

22. The quantum dot light-emitting device as described in claim 21, wherein, The P-type dopant includes at least one of the following: halogen-containing small organic molecules and their derivatives, cyano-containing small molecules and their derivatives, nitrogen-containing heterocyclic small molecules and their derivatives, and molecules containing Lewis acid-base pairs and their derivatives.

23. The quantum dot light-emitting device as described in claim 22, wherein, The P-type dopant includes at least one of F4-TCNQ, F6-TCNQ, HAT-CN, and benzoyl peroxide.

24. The quantum dot light-emitting device according to any one of claims 1-23, wherein, The number of hole transport layers is greater than one, and at least one of the hole transport layers adopts the distribution of the P-type dopant in the quantum dot light-emitting device as described in any one of claims 1-23.

25. The quantum dot light-emitting device according to any one of claims 1-24, wherein, The hole transport layer includes a cross-linked network structure.

26. A display device, wherein, Including the quantum dot light-emitting device as described in any one of claims 1-25.

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