A quantum dot light-emitting diode and its preparation method and bidirectional alternating light-emitting system

Abstract

The present application provides a quantum dot light-emitting diode, a preparation method thereof, and a bidirectional alternating light-emitting system. The quantum dot light-emitting diode includes a common electrode layer, which is used to transmit electrons and holes and is connected to a first end of an external AC power source; a cathode metal layer and an anode metal layer, wherein the cathode metal layer is arranged above the common electrode layer, and the anode metal layer is arranged below the common electrode layer, and the cathode metal layer and the anode metal layer have different polarities and are respectively used to be connected to a second end of an external AC power source; a first quantum dot light-emitting functional layer and a second quantum dot light-emitting functional layer, wherein the first quantum dot light-emitting functional layer is arranged between the common electrode layer and the cathode metal layer, and the second quantum dot light-emitting functional layer is arranged between the common electrode layer and the anode metal layer, so that the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer emit light alternately when the direction of the external AC power supply current changes continuously.

Description

Technical Field

[0001] The present application relates to the technical field of diodes, and in particular to a quantum dot light emitting diode and a preparation method thereof and a bidirectional alternating light emitting system. Background Art

[0002] The current mainstream quantum dot light emitting diodes (QLEDs) can only emit light in one direction or in both directions at the same time. However, in some specific application scenarios, quantum dot light emitting diodes that can emit light alternately on both sides are more suitable. However, there is currently no good quantum dot diode structure design that can emit light alternately on both sides. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a quantum dot light-emitting diode and a method for preparing the same and a bidirectional alternating light-emitting system, so as to provide a quantum dot light-emitting diode and a preparation and application system thereof to solve the problem that there is currently no good double-sided alternating light-emitting quantum dot diode structure design.

[0004] In a first aspect, an embodiment of the present invention provides a quantum dot light-emitting diode, comprising: a common electrode layer, which is used to transmit electrons and holes; a first quantum dot light-emitting functional layer, which is arranged on the upper surface of the common electrode layer to receive holes transmitted by the common electrode layer; a second quantum dot light-emitting functional layer, which is arranged on the lower surface of the common electrode layer to receive electrons transmitted by the common electrode layer; a cathode metal layer, which is arranged on the upper surface of the first quantum dot light-emitting functional layer to transmit electrons to the first quantum dot light-emitting functional layer, so that the first quantum dot light-emitting functional layer emits light after reacting with the holes transmitted by the common electrode layer and the electrons transmitted by the cathode metal layer; an anode metal layer, which is arranged on the lower surface of the second quantum dot light-emitting functional layer to transmit holes to the second quantum dot light-emitting functional layer, so that the second quantum dot light-emitting functional layer emits light after reacting with the electrons transmitted by the common electrode layer and the holes transmitted by the cathode metal layer.

[0005] In the quantum dot light-emitting diode designed as above, the cathode metal layer and the common electrode layer can transmit electrons and holes to the first quantum dot light-emitting functional layer respectively, and the anode metal layer and the common electrode layer can transmit holes and electrons to the second quantum dot light-emitting functional layer respectively, so that after the common electrode layer, the cathode metal layer and the anode metal layer are connected to the external AC power supply, when the supply current of the external AC power supply continuously changes in the positive and reverse directions, the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer continuously and alternately emit light, thereby breaking the barrier that quantum dot light-emitting diodes can only emit light in one direction or two directions, and solving the problem that there is currently no good quantum dot diode structure design for alternating double-sided light emission, so that the quantum dot light-emitting diode can emit light alternately on both sides, and is thus suitable for more practical scenarios, thereby improving the applicability of quantum dot diodes.

[0006] In an optional embodiment of the first aspect, the first quantum dot light-emitting functional layer includes a first hole transport layer arranged on the upper surface of the common electrode layer, a first light-emitting layer arranged on the upper surface of the first hole transport layer, and a first electron transport layer arranged on the upper surface of the first light-emitting layer; the second quantum dot light-emitting functional layer includes a second electron transport layer arranged on the lower surface of the common electrode layer, a second light-emitting layer arranged on the lower surface of the second electron transport layer, and a second hole transport layer arranged on the lower surface of the second light-emitting layer; the cathode metal layer is arranged on the upper surface of the first electron transport layer, and the anode metal layer is arranged on the lower surface of the second hole transport layer.

[0007] In an optional embodiment of the first aspect, the first quantum dot light-emitting functional layer also includes a first hole injection layer, which is arranged between the common electrode layer and the first hole transport layer; the second quantum dot light-emitting functional layer also includes a second hole injection layer, which is arranged between the anode metal layer and the second hole transport layer.

[0008] In an optional embodiment of the first aspect, the common electrode layer includes a connecting layer for transmitting holes to the first quantum dot light-emitting functional layer and a metal reflective electrode layer for transmitting electrons to the second quantum dot light-emitting functional layer, the metal reflective electrode layer is arranged on the upper surface of the second electron transport layer, the connecting layer is arranged on the upper surface of the metal reflective electrode layer, and the first hole injection layer is arranged on the upper surface of the connecting layer.

[0009] In a second aspect, an embodiment of the present invention provides a method for preparing a quantum dot light-emitting diode, which is used to prepare the quantum dot light-emitting diode described in any embodiment of the first aspect, and the method includes: depositing the anode metal layer on a transparent substrate; depositing the second quantum dot light-emitting functional layer on the deposited anode metal layer; depositing the common electrode layer on the deposited second quantum dot light-emitting functional layer; depositing the first quantum dot light-emitting functional layer on the deposited common electrode layer; and depositing the cathode metal layer on the first quantum dot light-emitting functional layer to complete the preparation of the quantum dot light-emitting diode.

[0010] In the quantum dot light-emitting diode prepared by the above preparation method, the cathode metal layer and the common electrode layer can respectively transmit electrons and holes to the first quantum dot light-emitting functional layer, and the anode metal layer and the common electrode layer can respectively transmit holes and electrons to the second quantum dot light-emitting functional layer, so that after the common electrode layer, the cathode metal layer and the anode metal layer are connected to the external AC power supply, when the supply current of the external AC power supply continuously changes in the positive and reverse directions, the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer continuously and alternately emit light, thereby breaking the barrier that quantum dot light-emitting diodes can only emit light in one direction or two directions. There is currently no good design of a quantum dot diode structure that alternately emits light on both sides, which enables quantum dot light-emitting diodes to emit light alternately on both sides, thereby being suitable for more practical scenarios, thereby improving the applicability of quantum dot diodes.

[0011] In an optional implementation manner of the second aspect, depositing the common electrode layer on the deposited second quantum dot light-emitting functional layer comprises:

[0012] The metal reflective electrode layer is deposited on the deposited second quantum dot light-emitting functional layer, and the connection layer is deposited on the deposited metal reflective layer.

[0013] In an optional implementation manner of the second aspect, depositing the second quantum dot light-emitting functional layer on the deposited anode metal layer comprises:

[0014] The second hole transport layer is deposited on the deposited anode metal layer, the second light-emitting layer is deposited on the deposited second hole transport layer, and the second electron transport layer is deposited on the deposited second light-emitting layer to complete the preparation of the second quantum dot light-emitting functional layer; the depositing of the metal light-reflecting electrode layer on the deposited second quantum dot light-emitting functional layer includes: depositing the metal light-reflecting electrode layer on the deposited second electron transport layer; the depositing of the first quantum dot light-emitting functional layer on the deposited common electrode layer includes: depositing the first hole transport layer on the deposited connecting layer, depositing the first light-emitting layer on the deposited first hole transport layer, and depositing the first electron transport layer on the deposited first light-emitting layer to complete the preparation of the first quantum dot light-emitting functional layer; the depositing of the cathode metal layer on the first quantum dot light-emitting functional layer includes: depositing the cathode metal layer on the deposited first electron transport layer to complete the preparation of the quantum dot light-emitting diode.

[0015] In an optional embodiment of the second aspect, before depositing the second hole transport layer on the deposited anode metal layer, the method further includes: depositing the second hole injection layer on the deposited anode metal layer, and depositing the second hole transport layer on the deposited second hole injection layer.

[0016] In an optional embodiment of the second aspect, before depositing the first hole transport layer on the deposited connecting layer, the method further includes: depositing the first hole injection layer on the deposited connecting layer, and depositing the first hole transport layer on the deposited first hole injection layer.

[0017] In the third aspect, an embodiment of the present invention provides a bidirectional alternating light-emitting system, which comprises a quantum dot light-emitting diode described in any of the aforementioned embodiments of the first aspect or the second aspect and an AC power supply, one end of the AC power supply is connected to the common electrode layer, and the other end of the AC power supply is respectively connected to the cathode metal layer and the anode metal layer, so that the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer emit light alternately when the direction of the AC power supply current changes continuously. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the structure of a quantum dot diode provided in an embodiment of the present application;

[0020] Figure 2 A first schematic diagram of connecting a quantum dot diode and an AC power supply provided in an embodiment of the present application;

[0021] Figure 3 A second schematic diagram of connecting a quantum dot diode and an AC power supply provided in an embodiment of the present application;

[0022] Figure 4 A first specific structural diagram of a quantum dot diode provided in an embodiment of the present application;

[0023] Figure 5 A first specific schematic diagram of the connection between a quantum dot diode and an AC power supply provided in an embodiment of the present application;

[0024] Figure 6 A second specific schematic diagram of the connection between the quantum dot diode and the AC power supply provided in the embodiment of the present application;

[0025] Figure 7 A second specific structural diagram of a quantum dot diode provided in an embodiment of the present application;

[0026] Figure 8 A third specific structural diagram of a quantum dot diode provided in an embodiment of the present application;

[0027] Fig. 9 A first flow chart of a method for preparing a quantum dot diode provided in an embodiment of the present application;

[0028] Fig.10 A second flow chart of the method for preparing a quantum dot diode provided in an embodiment of the present application;

[0029] Fig.11 A structural schematic diagram of a bidirectional light emitting system is provided for an embodiment of the present application.

[0030] Icon: 1-quantum dot light-emitting diode; 2-AC power supply; 10-common electrode layer; 101-connecting layer; 102-metal reflective electrode layer; 20-cathode metal layer; 30-anode metal layer; 40-first quantum dot light-emitting functional layer; 401-first hole transport layer; 402-first light-emitting layer; 403-first electron transport layer; 404-first hole injection layer; 50-second quantum dot light-emitting functional layer; 501-second electron transport layer; 502-second light-emitting layer; 503-second hole transport layer; 504-second hole injection layer; 60-first transparent substrate; 70-second transparent substrate. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0032] First embodiment

[0033] The embodiment of the present application provides a quantum dot light-emitting diode, which can realize double-sided alternating light emission, that is, alternating light emission from the top and the bottom. The double-sided alternating light-emitting quantum dot light-emitting diode can be applied to neon light advertisements and two-way display scenarios. For example, when applied to neon light advertisements, the neon billboard can display the front and back sides alternately, thereby increasing the advertising effect and attracting user attention. In addition, the colors that can be displayed alternately in both directions can be set to different colors, so that the quantum dot light-emitting diode using the present design can realize the alternating display of two color layouts, thereby increasing the advertising effect.

[0034] like Figure 1 As shown, the quantum dot light-emitting diode specifically includes the following structure: a common electrode layer 10, a cathode metal layer 20, an anode metal layer 30, a first quantum dot light-emitting functional layer 40 and a second quantum dot light-emitting functional layer 50, wherein the common electrode layer 10 is arranged in the middle, the first quantum dot light-emitting functional layer 40 is arranged on the upper surface of the common electrode layer 10, the cathode metal layer 20 is arranged on the upper surface of the first quantum dot light-emitting functional layer 40, the second quantum dot light-emitting functional layer 50 is arranged on the lower surface of the common electrode layer 10, and the anode metal layer 30 is arranged on the lower surface of the second quantum dot light-emitting functional layer 50, wherein the cathode metal layer 20 can transmit electrons to the first quantum dot light-emitting functional layer 40, and the anode metal layer 30 can transmit holes to the second quantum dot light-emitting functional layer 50; The common electrode layer 10 can transmit both electrons and holes. Specifically, the common electrode layer 10 can transmit holes to the first quantum dot light-emitting functional layer 40, and the common electrode layer 10 can also transmit electrons to the second quantum dot light-emitting functional layer 50. In this way, when the first quantum dot light-emitting functional layer 40 obtains electrons transmitted by the cathode metal layer 20 and holes transmitted by the common electrode layer 10, the holes and electrons react inside the first quantum dot light-emitting functional layer 40, thereby causing the first quantum dot light-emitting functional layer 40 to emit light; when the second quantum dot light-emitting functional layer 50 obtains holes transmitted by the anode metal layer 30 and electrons transmitted by the common electrode layer 10, the holes and electrons react inside the second quantum dot light-emitting functional layer 50, thereby causing the second quantum dot light-emitting functional layer 50 to emit light.

[0035] When the quantum dot light-emitting diode with the above-mentioned structural design is used, the common electrode layer 10 of the quantum dot light-emitting diode can be connected to one end of an external AC power supply, and the cathode metal layer 20 and the anode metal layer 30 can be connected to the other end of the external AC power supply respectively. In this way, when the AC power supply is turned on, the direction of the power supply current of the AC power supply is constantly changing. This will cause the first quantum dot light-emitting functional layer 40 to emit light when the power supply current is in one direction, while the second quantum dot light-emitting functional layer 50 will not emit light at this time. When the power supply current changes to another direction, the second quantum dot light-emitting functional layer 50 will emit light while the first quantum dot light-emitting functional layer 40 will not emit light. In this way, under the action of the AC power supply, the quantum dot light-emitting diode designed in the above scheme can realize the alternating light emission of the first quantum dot light-emitting functional layer 40 and the second quantum dot light-emitting functional layer 50. Specifically, the cathode metal layer 20, the anode metal layer 30 and the common electrode layer 10 can be connected to the AC power supply as shown in Figure 2 As shown, the direction of the supply current of the AC power supply at this time is that the polarity of the connection end between it and the common electrode layer 10 is negative, and the polarity of the connection end between it and the cathode metal layer 20 and the anode metal layer 30 is positive. At this time, the common electrode layer 10 receives the electrons transmitted by the AC power supply. After receiving the electrons transmitted by the AC power supply, the common electrode layer 10 will only transmit the electrons to the second quantum dot light-emitting functional layer 50. At the same time, the cathode metal layer 20 and the anode metal layer 30 are connected to the positive polarity end of the AC power supply, so that the AC power supply will only transmit holes to the anode metal layer 30. In this way, the second quantum dot light-emitting functional layer 50 can receive the electrons transmitted by the common electrode layer 10 and the holes transmitted by the anode metal layer 30 and then emit light, while the first quantum dot light-emitting functional layer 40 does not receive the holes transmitted by the common electrode layer 10 and the electrons transmitted by the cathode metal layer and thus does not emit light; and when the direction of the supply current of the AC power supply is opposite, such as Figure 3 As shown, the first quantum dot light-emitting functional layer 40 receives holes transmitted by the common electrode layer 10 and electrons transmitted by the cathode metal layer and emits light, while the second quantum dot light-emitting functional layer 50 cannot receive electrons transmitted by the common electrode layer 10 and holes transmitted by the anode metal layer 30 and does not emit light.

[0036] In the quantum dot light-emitting diode designed as above, the cathode metal layer and the common electrode layer can transmit electrons and holes to the first quantum dot light-emitting functional layer respectively, and the anode metal layer and the common electrode layer can transmit holes and electrons to the second quantum dot light-emitting functional layer respectively, so that after the common electrode layer, the cathode metal layer and the anode metal layer are connected to the external AC power supply, when the supply current of the external AC power supply continuously changes in the positive and reverse directions, the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer continuously and alternately emit light, thereby breaking the barrier that quantum dot light-emitting diodes can only emit light in one direction or two directions, and solving the problem that there is currently no good quantum dot diode structure design for alternating double-sided light emission, so that the quantum dot light-emitting diode can emit light alternately on both sides, and is thus suitable for more practical scenarios, thereby improving the applicability of quantum dot diodes.

[0037] In an optional implementation of this embodiment, it has been described above that the common electrode layer 10 can transmit both electrons and holes, that is, the common electrode layer 10 can be used as the anode of the first quantum dot light-emitting functional layer 40 and as the cathode of the second quantum dot light-emitting functional layer 50. In this case, the designed quantum dot light-emitting diode can be as follows: Figure 4 The structure, wherein the common electrode layer 10 includes a connection layer 101 for transmitting holes to the first quantum dot light-emitting functional layer 40 and a metal reflective electrode layer 102 for transmitting electrons to the second quantum dot light-emitting functional layer 50, and the metal reflective electrode layer 102 is arranged on the lower surface of the connection layer 101; the first quantum dot light-emitting functional layer 40 includes a first hole transport layer 401, a first light-emitting layer 402 and a first electron transport layer 403 arranged on the connection layer 101 from bottom to top, and the cathode metal layer 20 is arranged on the first electron transport layer 403; the second quantum dot light-emitting functional layer 50 includes a second electron transport layer 501, a second light-emitting layer 502 and a second hole transport layer 503 arranged under the metal reflective electrode layer 102 from top to bottom, and the anode metal layer 30 is arranged below the second hole transport layer 503; wherein the connection layer 101 can be connected to one end of an external AC power supply, and the cathode metal layer 20 and the anode metal layer 30 can be connected to the other end of the AC power supply respectively.

[0038] It is worth noting that, since hole transport is more difficult, considering the energy level matching, the material of the connecting layer 101 in this scheme is usually ITO indium tin oxide or IZO indium zinc oxide or AZO aluminum zinc oxide and other materials, but the connecting layer 101 formed by these materials is in a transparent state. In order to achieve reflection and transmit electrons to the second quantum dot light-emitting functional layer 50 at the same time, the structure under the connecting layer 101 is set to a metal reflective electrode layer 102 to simultaneously achieve the functions of luminescence and electron transmission, wherein the thickness of the metal reflective electrode layer 102 can be adaptively set so that more than 98% of the light is reflected back.

[0039] The quantum dot light-emitting diode obtained by the above design has a current direction of Figure 5 As shown, when the polarity of the AC power supply at the connection end with the connection layer 101 is negative, and the polarity of the connection end with the cathode metal layer 20 and the anode metal layer 30 is positive, for the first quantum dot light-emitting functional layer 40, the connection layer 101 receives the electrons transmitted from the negative end of the AC power supply. Since the first hole transport layer 401 is connected to the connection layer 101, it cannot transmit electrons. Therefore, the electrons cannot be transmitted to the first light-emitting layer of the first quantum dot light-emitting functional layer 40. At the same time, the cathode metal layer 20 is connected to the positive end of the AC power supply, and it receives holes. The cathode metal layer 20 is connected to the first electron transport layer 403 below, and the holes cannot be transmitted in the first electron transport layer 403. Therefore, the holes cannot be transmitted to the first light-emitting layer 402, so the upper half of the quantum dot diode does not emit light;

[0040] As for the second quantum dot light-emitting functional layer 50, the connecting layer 101 receives electrons transmitted from the negative end of the AC power supply. Since the connecting layer 101 is connected to the metal reflective electrode layer 102 below, the electrons can be transmitted to the metal reflective electrode layer 102 through the connecting layer 101. The metal reflective electrode layer 102 is connected to the second electron transport layer 501 below, which can transport electrons and transmit the electrons into the second light-emitting layer 502. At the same time, the anode metal layer 30 is connected to the positive end of the AC power supply and receives holes. The anode metal layer 30 is provided with the second hole transport layer 503 above it, which can transport holes and transmit them into the second light-emitting layer 502. In this way, the electrons and holes enter the second light-emitting layer 502 to react, thereby causing the second light-emitting layer 502 to emit light, so that the lower half of the quantum dot diode emits light.

[0041] In addition, when the direction of the supply current of the AC power supply changes, that is, the direction of the supply current is opposite to the above-mentioned direction, the quantum dot light-emitting diode obtained by the above-mentioned design Figure 6As shown, when the polarity of the connection end with the connection layer 101 is positive, and the polarity of the connection end with the cathode metal layer 20 and the anode metal layer 30 is negative, for the first quantum dot light-emitting functional layer 40, the connection layer 101 receives holes transmitted from the positive end of the AC power supply. Since the first hole transport layer 401 is connected to the connection layer 101, it can transmit holes. Therefore, the holes are transmitted to the first light-emitting layer of the first quantum dot light-emitting functional layer 40 through the first hole transport layer 401. At the same time, the cathode metal layer 20 is connected to the negative end of the AC power supply, and it receives electrons. The cathode metal layer 20 is connected to the first electron transport layer 403 below. The first electron transport layer 403 can transport electrons and transfer them into the first light-emitting layer 402, so that the holes and electrons enter the first light-emitting layer 402 to react, so that the first light-emitting layer 402 emits light, that is, the upper half of the quantum dot light-emitting diode emits light;

[0042] As for the second quantum dot light-emitting functional layer 50, the connecting layer 101 receives holes transmitted from the positive end of the AC power supply. Since the connecting layer 101 is connected to the metal reflective electrode layer 102 and the second electron transport layer 501, it cannot transmit holes and the received holes cannot enter the second light-emitting layer 502. At the same time, the anode metal layer 30 is connected to the negative end of the AC power supply and receives electrons. The anode metal layer 30 is provided with the second hole transport layer 503, which cannot transmit electrons into the second light-emitting layer 502. In this way, neither electrons nor holes can enter the second light-emitting layer 502, so that the lower half of the quantum dot diode cannot emit light. The quantum dot diode designed as above realizes the bidirectional alternating light emission of the quantum dot diode.

[0043] In an optional implementation of this embodiment, if Figure 7 As shown, the first quantum dot light-emitting functional layer 40 designed above may also include a first hole injection layer 404, which is arranged between the connecting layer 101 and the first hole transport layer 401, and is used to accelerate the transmission speed of holes; at the same time, the second quantum dot light-emitting functional layer 50 designed above may also include a second hole injection layer 504, which is arranged between the second hole transport layer 503 and the anode metal layer 30, and is used to accelerate the transmission speed of holes.

[0044] In an optional implementation manner of this embodiment, the thickness and width of the first quantum dot light-emitting functional layer 40 and the second quantum dot light-emitting functional layer 50 mentioned above can be set to be the same or to have different widths and thicknesses.

[0045] In an optional implementation of this embodiment, if Figure 8As shown, the quantum dot diode may also include a first transparent substrate 60 and a second transparent substrate 70, wherein the first transparent substrate 60 is arranged on the lower surface of the anode metal layer 30, and the second transparent substrate 70 is arranged on the upper surface of the cathode metal layer 20; wherein, the width of the first transparent substrate 60 may be greater than the width of the anode metal layer 30, the width of the second transparent substrate 70 may be greater than the width of the cathode metal layer 20, and the widths of the first transparent substrate 60 and the second transparent substrate 70 may be equal; the colors of the light-emitting layer in the first quantum dot light-emitting functional layer 40 and the light-emitting layer in the second quantum dot light-emitting functional layer 50 may be set to be different, and of course may also be set to be the same, and may be set according to actual conditions.

[0046] Second embodiment

[0047] The present application also provides a method for preparing a quantum dot light-emitting diode, which is used to prepare a quantum dot light-emitting diode capable of bidirectional alternating light emission as described in any implementation manner of the first embodiment, such as Fig. 9 As shown, the preparation method specifically comprises the following steps:

[0048] Step S200: depositing an anode metal layer on a transparent substrate.

[0049] Step S201: depositing a second quantum dot light-emitting functional layer on the deposited anode metal layer.

[0050] Step S202: depositing a common electrode layer on the deposited second quantum dot light-emitting functional layer.

[0051] Step S203: depositing a first quantum dot light-emitting functional layer on the deposited common electrode layer.

[0052] Step S204: depositing the cathode metal layer on the deposited first quantum dot light-emitting functional layer.

[0053] The anode metal layer, the second quantum dot light-emitting functional layer, the first quantum dot light-emitting functional layer and the cathode metal layer in the above steps are all consistent with those described in the first embodiment; in addition, after the cathode metal layer is deposited, a transparent substrate or base plate can be set thereon, or the cathode metal layer can be directly deposited on the substrate or base plate and then connected to the first quantum dot light-emitting functional layer.

[0054] In an optional implementation of this embodiment, if Fig.10 As shown, the aforementioned quantum dot light-emitting diode can be prepared by the following steps:

[0055] Step S201 deposits a second quantum dot light-emitting functional layer on the deposited anode metal layer, which may specifically include the following steps:

[0056] Step S2010: depositing a second hole injection layer on the deposited anode metal layer.

[0057] Step S2011: depositing a second hole transport layer on the deposited second hole injection layer.

[0058] Step S2012: depositing a second light-emitting layer on the deposited second hole transport layer.

[0059] Step S2013: depositing a second electron transport layer on the deposited second light-emitting layer.

[0060] After the second quantum dot light-emitting functional layer is deposited, step S202 is to deposit a common electrode layer on the deposited second quantum dot light-emitting functional layer, which specifically includes the following steps:

[0061] Step S2020: depositing a metal light-reflecting electrode layer on the deposited second electron transport layer.

[0062] Step S2021: depositing a connection layer on the deposited metal reflective layer.

[0063] After the common electrode layer is deposited, step S203 deposits a first quantum dot light-emitting functional layer on the deposited common electrode layer, which may specifically include the following steps:

[0064] Step S2030: depositing a first hole injection layer on the deposited connection layer.

[0065] Step S2031: depositing a first hole transport layer on the deposited first hole injection layer.

[0066] Step S2032: depositing a first light-emitting layer on the deposited first hole transport layer.

[0067] Step S2033: depositing a first electron transport layer on the deposited first light-emitting layer.

[0068] After the first quantum dot light-emitting functional layer is completely deposited, step S204 is to deposit the cathode metal layer on the deposited first quantum dot light-emitting functional layer, which specifically includes:

[0069] Step S2040: depositing a cathode metal layer on the deposited first electron transport layer to complete the preparation of the quantum dot light emitting diode.

[0070] Third embodiment

[0071] The present application provides a bidirectional alternating light emitting system, such as Fig.11As shown, the system includes a quantum dot light emitting diode 1 obtained by any method in the first embodiment or the second embodiment and an AC power supply 2, one end of the AC power supply is connected to the common electrode layer 10, and the other end of the AC power supply is respectively connected to the cathode metal layer 20 and the anode metal layer 30, so that when the direction of the supply current of the AC power supply 2 is continuously changed, the first quantum dot light emitting functional layer 40 and the second quantum dot light emitting functional layer 50 emit light alternately, wherein the specific light emission principle and connection method have been explained in detail in the first embodiment and will not be repeated here.

[0072] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0073] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0074] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A quantum dot light emitting diode, characterized in that: include: A common electrode layer, which is used to transport electrons and holes; A first quantum dot light-emitting functional layer, which is disposed on the upper surface of the common electrode layer to receive holes transmitted by the common electrode layer; A second quantum dot light-emitting functional layer, which is disposed on the lower surface of the common electrode layer to receive electrons transmitted by the common electrode layer; a cathode metal layer, which is disposed on the upper surface of the first quantum dot light-emitting functional layer, and is used to transmit electrons to the first quantum dot light-emitting functional layer, so that the first quantum dot light-emitting functional layer emits light after reacting with the holes transmitted by the common electrode layer and the electrons transmitted by the cathode metal layer; an anode metal layer, which is disposed on the lower surface of the second quantum dot light-emitting functional layer, and is used to transmit holes to the second quantum dot light-emitting functional layer, so that the second quantum dot light-emitting functional layer emits light after reacting with the electrons transmitted by the common electrode layer and the holes transmitted by the cathode metal layer; The first quantum dot light-emitting functional layer includes a first hole transport layer disposed on the upper surface of the common electrode layer, a first light-emitting layer disposed on the upper surface of the first hole transport layer, and a first electron transport layer disposed on the upper surface of the first light-emitting layer; The second quantum dot light-emitting functional layer includes a second electron transport layer disposed on the lower surface of the common electrode layer, a second light-emitting layer disposed on the lower surface of the second electron transport layer, and a second hole transport layer disposed on the lower surface of the second light-emitting layer; The cathode metal layer is disposed on the upper surface of the first electron transport layer, and the anode metal layer is disposed on the lower surface of the second hole transport layer; Wherein, the thickness and width of the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer are the same; The quantum dot light emitting diode further includes a first transparent substrate and a second transparent substrate. The first transparent substrate is disposed on the lower surface of the anode metal layer, and the second transparent substrate is disposed on the upper surface of the cathode metal layer.

2. The quantum dot light emitting diode according to claim 1, characterized in that: The first quantum dot light-emitting functional layer also includes a first hole injection layer, which is arranged between the common electrode layer and the first hole transport layer; the second quantum dot light-emitting functional layer also includes a second hole injection layer, which is arranged between the anode metal layer and the second hole transport layer.

3. The quantum dot light emitting diode according to claim 2, characterized in that: The common electrode layer includes a connecting layer for transmitting holes to the first quantum dot light-emitting functional layer and a metal light-reflecting electrode layer for transmitting electrons to the second quantum dot light-emitting functional layer, the metal light-reflecting electrode layer is arranged on the upper surface of the second electron transport layer, the connecting layer is arranged on the upper surface of the metal light-reflecting electrode layer, and the first hole injection layer is arranged on the upper surface of the connecting layer.

4. A method for preparing a quantum dot light-emitting diode, characterized in that: For preparing a quantum dot light-emitting diode according to any one of claims 1 to 3, the method comprises: Depositing the anode metal layer on a transparent substrate; Depositing the second quantum dot light-emitting functional layer on the deposited anode metal layer; Depositing the common electrode layer on the deposited second quantum dot light-emitting functional layer; Depositing the first quantum dot light-emitting functional layer on the deposited common electrode layer; The cathode metal layer is deposited on the first quantum dot light-emitting functional layer to complete the preparation of the quantum dot light-emitting diode.

5. The preparation method according to claim 4, characterized in that: The step of depositing the common electrode layer on the deposited second quantum dot light-emitting functional layer comprises: A metal light-reflecting electrode layer is deposited on the deposited second quantum dot light-emitting functional layer, and a connecting layer is deposited on the deposited metal light-reflecting electrode layer.

6. The preparation method according to claim 5, characterized in that: The step of depositing the second quantum dot light-emitting functional layer on the deposited anode metal layer comprises: Depositing a second hole transport layer on the deposited anode metal layer, depositing a second light-emitting layer on the deposited second hole transport layer, and depositing a second electron transport layer on the deposited second light-emitting layer to complete the preparation of the second quantum dot light-emitting functional layer; The step of depositing the metal light-reflecting electrode layer on the deposited second quantum dot light-emitting functional layer comprises: depositing the metal light-reflecting electrode layer on the deposited second electron transport layer; The step of depositing the first quantum dot light-emitting functional layer on the deposited common electrode layer comprises: depositing a first hole transport layer on the deposited connecting layer, depositing a first light-emitting layer on the deposited first hole transport layer, and depositing a first electron transport layer on the deposited first light-emitting layer, so as to complete the preparation of the first quantum dot light-emitting functional layer; The step of depositing the cathode metal layer on the first quantum dot light-emitting functional layer comprises: The cathode metal layer is deposited on the first electron transport layer to complete the preparation of the quantum dot light emitting diode.

7. The method according to claim 6, characterized in that Before depositing the second hole transport layer on the deposited anode metal layer, the method further comprises: A second hole injection layer is deposited on the deposited anode metal layer, and the second hole transport layer is deposited on the deposited second hole injection layer.

8. The method according to claim 6, characterized in that Before depositing the first hole transport layer on the deposited connection layer, the method further includes: A first hole injection layer is deposited on the deposited connection layer, and the first hole transport layer is deposited on the deposited first hole injection layer.

9. A bidirectional alternating light emitting system, characterized in that: The bidirectional alternating light-emitting system comprises a quantum dot light-emitting diode as described in any one of claims 1 to 3 and an AC power supply, one end of the AC power supply is connected to the common electrode layer, and the other end of the AC power supply is respectively connected to the cathode metal layer and the anode metal layer, so that the first quantum dot light-emitting functional layer and the second quantum dot light-emitting functional layer emit light alternately when the direction of the AC power supply current changes continuously.

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