WO2020057027A1 - 有机发光二极管和显示面板 - Google Patents

有机发光二极管和显示面板 Download PDF

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Publication number
WO2020057027A1
WO2020057027A1 PCT/CN2019/071949 CN2019071949W WO2020057027A1 WO 2020057027 A1 WO2020057027 A1 WO 2020057027A1 CN 2019071949 W CN2019071949 W CN 2019071949W WO 2020057027 A1 WO2020057027 A1 WO 2020057027A1
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Prior art keywords
hole blocking
sub
layer
energy level
light emitting
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PCT/CN2019/071949
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English (en)
French (fr)
Inventor
李维维
彭兆基
何麟
田景文
李田田
李梦真
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云谷（固安）科技有限公司
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Publication of WO2020057027A1 publication Critical patent/WO2020057027A1/zh
Priority to US16/865,741 priority Critical patent/US11362294B2/en

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/18—Carrier blocking layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/10—OLED displays
    • H10K59/12—Active-matrix OLED [AMOLED] displays
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00
    • H10K2101/30—Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00
    • H10K2101/40—Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/351—Thickness

Definitions

  • the present application relates to the field of display technology, and in particular, to an organic light emitting diode and a display panel.
  • Organic Light-Emitting Diode uses a self-luminous light-emitting mechanism, which does not require a backlight. When it is applied to a display panel and a display device, the overall thickness of the display panel and the display device is thin, which is conducive to the realization of the display. Lightweight design of panels and display devices. At the same time, organic light emitting diodes have the advantages of high display brightness, wide viewing angle, and fast response speed.
  • the present application provides an organic light emitting diode and a display panel to improve the life of the organic light emitting diode.
  • the present application provides an organic light emitting diode, which includes: a first electrode, a second electrode, a light emitting layer, and a hole blocking layer;
  • the first electrode is opposite to the second electrode
  • the light emitting layer is located between the first electrode and the second electrode;
  • the hole blocking layer is located between the light emitting layer and the second electrode;
  • the hole blocking layer includes at least two sub hole blocking layers stacked, and the LUMO energy levels of the at least two sub hole blocking layers are sequentially reduced.
  • the LUMO energy levels of the at least two sub-hole blocking layers are sequentially decreased, and the HOMO energy levels of the at least two sub-hole blocking layers are sequentially decreased.
  • the LUMO energy level of any one of the sub-hole blocking layers is lower than the LUMO energy level of the light emitting layer.
  • the LUMO energy levels of the at least two sub-hole blocking layers are sequentially decreased, and the HOMO energy levels of the at least two sub-hole blocking layers are sequentially decreased.
  • the LUMO energy level of any one of the sub-hole blocking layers is lower than the LUMO energy level of the light emitting layer.
  • the value range of the energy level difference L1 of the LUMO energy levels of the two adjacent sub-hole blocking layers is L1 ⁇ 0.15eV.
  • the value range of the energy level difference L1 of the LUMO energy levels of the two adjacent sub-hole blocking layers is L1 ⁇ 0.1eV.
  • the energy level difference L2 between the LUMO energy level of the light emitting layer and the LUMO energy level of the sub hole blocking layer having the highest LUMO energy level among the at least two sub hole blocking layers is in a range of L2 ⁇ 0.1eV. ;
  • the sub-hole blocking layer having the highest LUMO energy level is a sub-hole blocking layer having a LUMO energy level closest to a LUMO energy level of the light-emitting layer.
  • the energy level difference L2 between the LUMO energy level of the light emitting layer and the LUMO energy level of the sub hole blocking layer having the highest LUMO energy level among the at least two sub hole blocking layers is in a range of L2 ⁇ 0.08eV. .
  • the energy level difference H1 between the HOMO level of at least one of the sub-hole blocking layers and the HOMO level of the light-emitting layer ranges from 0.2eV ⁇ H1 ⁇ 0.5eV. .
  • an energy level difference H1 between the HOMO level of the sub-hole blocking layer and the HOMO level of the light emitting layer ranges from 0.3eV ⁇ H1 ⁇ 0.4eV. .
  • the thickness T1 of the any one of the sub-hole blocking layers ranges from 0 nm ⁇ T1 ⁇ 5 nm.
  • the thickness T1 of any one of the sub-hole blocking layers ranges from 0 nm ⁇ T1 ⁇ 3.5 nm.
  • the thickness T2 of the sub-hole blocking layer adjacent to the light emitting layer ranges from 2 nm ⁇ T2 ⁇ 3 nm.
  • the thickness T2 of the sub-hole blocking layer adjacent to the light emitting layer ranges from 2.3 nm ⁇ T2 ⁇ 2.8 nm.
  • first carrier function layer and a second carrier function layer
  • the first carrier function layer is located between the first electrode and the light emitting layer
  • the second carrier function layer is located between the hole blocking layer and the second electrode.
  • the present application also provides a display panel including a base substrate and a plurality of pixel units arranged in an array on one side of the base substrate;
  • the pixel unit includes any one of the foregoing organic light emitting diodes provided in the present application.
  • FIG. 1 is a schematic structural diagram of an organic light emitting diode according to an embodiment
  • FIG. 2 is a schematic structural diagram of another organic light emitting diode according to an embodiment
  • FIG. 3 is a schematic diagram of an energy level structure of an organic light emitting diode according to an embodiment
  • FIG. 4 is a schematic diagram of an energy level structure of another organic light emitting diode according to an embodiment
  • FIG. 5 is a schematic structural diagram of still another organic light emitting diode according to an embodiment
  • FIG. 6 is a schematic diagram of an energy level structure of still another organic light emitting diode according to an embodiment
  • FIG. 7 is a schematic structural diagram of a display panel according to an embodiment.
  • the material of the light-emitting layer of the organic light-emitting diode with excellent performance is an electron-transport-type material.
  • the organic light-emitting diode further includes first and second electrodes on both sides of the light-emitting layer.
  • the first electrode may be The anode and the second electrode may be a cathode.
  • the material of the light emitting layer is a material that is biased to an electron transport type, the material of the light emitting layer is advantageous The transmission of electrons, so that a large number of electrons reach the light emitting layer, thereby improving the current efficiency of the organic light emitting diode.
  • the number of electrons in the light-emitting layer is larger than the number of holes, too many electrons cannot be recombined, and the part of the electrons that cannot be recombined is transferred to the film layer between the light-emitting layer and the first electrode.
  • Deteriorating the performance of these film layers and the interface between adjacent film layers results in the degradation of the film layer performance between the light emitting layer and the first electrode in the organic light emitting diode, and leads to multiple degradations between the light emitting layer and the first electrode.
  • the interface between adjacent film layers in the film layer is destroyed, which results in a decrease in the life of the organic light emitting diode, that is, the life of the organic light emitting diode is short.
  • an embodiment of the present application provides an organic light emitting diode to improve the life of the organic light emitting diode.
  • FIG. 1 is a schematic structural diagram of an organic light emitting diode according to an embodiment.
  • the organic light emitting diode 10 includes: a first electrode 11, a second electrode 12, a light emitting layer 13, and a hole blocking layer 14; the first electrode 11 is disposed opposite to the second electrode 12; the light emitting layer 13 is located on the first electrode Between the 11 and the second electrode 12; the hole blocking layer 14 is located between the light emitting layer 13 and the second electrode 12; wherein the hole blocking layer 14 includes at least two sub-hole blocking layers (exemplary, FIG.
  • the hole blocking layer 14 includes two sub-hole blocking layers, which are respectively shown as a first sub-hole blocking layer 141 and a second sub-hole blocking layer 142, and the first The sub-hole blocking layer 141 is located on the side of the second sub-hole blocking layer 142 near the light-emitting layer 13), and at least two sub-hole blocking layers (the first sub-hole blocking layer 141 and the second sub-space are shown in FIG. 1).
  • the cavity barrier layer 142 (shown in FIG. 1) decreases the LUMO energy level in order.
  • the first electrode 11 may be an anode.
  • a material of the first electrode 11 may be indium tin oxide (ITO).
  • the second electrode 12 may be a cathode.
  • the material of the second electrode 12 may be a metal material, such as aluminum (Al), gold (Au), silver (Ag), or a metal alloy including Ag, which has a lower work function.
  • the light-emitting layer 13 may include a host material and a guest material.
  • the host material may be 8-hydroxyquinoline aluminum (Alq3), 9,10-bis (1-naphthyl) anthracene (ADN), 4,4'- Bis (9H-carbazole-9-yl) biphenyl (CBP); guest material can be 2-tert-butyl-4- (dicyanomethylene) -6- [2- (1,1,7, 7-tetramethyljulonidin-9-yl) vinyl] -4H-pyran (DCJBT), N, N'-dimethylquinacridone (DMQA), N, N'-dibutyl Quinacridone (DBQA), Coumarin 545T (C545T), 5,12-dibutyl-1,3,8,10-tetramethylquinacridone (TMDBQA), 4,4'-bis ( 9-ethyl-3-carbazolevinyl) -1,1'-biphenyl (BCzVBi), 4,4'-bis [4- (di-p-toly
  • the light-emitting principle of the organic light-emitting diode 10 mainly includes four processes of carrier injection (carriers can be electrons or holes), carrier transport, carrier recombination, and exciton deexcitation light. Specifically, when a certain voltage is applied to the organic light emitting diode 10 (also can be understood as providing a driving current), the holes of the first electrode 11 (anode) and the electrons of the second electrode 12 (cathode) are injected into the light emitting layer 13 respectively.
  • the hole blocking layer 14 is disposed between the light emitting layer 13 and the second electrode 12 (cathode). Its function is mainly reflected in two aspects: on the one hand, it can block holes from the light emitting layer 13 to the second electrode 12 side. Therefore, more holes can be confined in the light emitting layer 13; on the other hand, it is beneficial for electrons to be transmitted from the second electrode 12 to the light emitting layer 13, so that the number of electrons in the light emitting layer 13 can be increased.
  • the material of the hole blocking layer 14 may be ((1,1'-diphenyl) -4-olato) bis (2-methyl-8-hydroxyquinoline NI, 08) aluminum (BAlq), 2,9- Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), bis [2-((oxo) diphenylphosphino) phenyl) ether (DPEPO), 4,7- Diphenyl-1,10-phenanthroline (Bphen) or other hole blocking layer materials known to those skilled in the art are not limited in the examples of the present application.
  • the single-layer hole blocking layer in the related art can be used.
  • the LUMO energy level is divided into at least two LUMO energy levels with a small energy level difference. Since the smaller LUMO energy level difference is more conducive to the transport of electrons, more electrons can be injected into the light-emitting layer 13 through the above-mentioned settings.
  • the electron transporting effect of the hole blocking layer 14 and the hole blocking effect are complementary, that is, the stronger the electron transporting effect of the hole blocking layer 14 is, the stronger the hole blocking effect of the hole blocking layer 14 is.
  • the above arrangement can also effectively prevent holes from being transmitted from the light-emitting layer 13 to the second electrode 12 side, so that more holes are confined in the light-emitting layer 13.
  • the number of electrons and holes in the light-emitting layer 13 can be increased at the same time, so that more electrons and holes are recombined in the light-emitting layer 13 for light emission, so the organic light-emitting diode 10 can be improved.
  • Luminous efficiency At the same time, since more electrons are recombined in the light-emitting layer 13, it is possible to reduce the damaging effect of the electrons on the film layer between the light-emitting layer 13 and the first electrode 11 and the interface between adjacent film layers, and slow down the film. The degradation of the layer performance and the degradation of the interface between adjacent film layers are slowed down, so that the life of the organic light emitting diode 10 can be improved.
  • the hole blocking layer 14 includes a first sub-hole blocking layer 141 and a second sub-hole blocking layer 142, wherein the LUMO energy level of the first sub-hole blocking layer 141 is lower than that of the second sub-hole blocking layer 141.
  • the LUMO energy level of the sub-hole blocking layer 142 In this structure, the material of the first sub-hole blocking layer 141 may be Bphen, and the material of the second sub-hole blocking layer 142 may be BCP. Alternatively, the LUMO energy level of the second sub-hole blocking layer 142 is lower than the LUMO energy level of the first sub-hole blocking layer 141.
  • the material of the first sub-hole blocking layer 141 may be BCP, and the second sub-space The material of the hole blocking layer 142 may be Bphen.
  • the first sub-hole blocking layer 141 and the second sub-hole blocking layer 142 may also adopt other hole blocking layer materials known to those skilled in the art, which is not limited in the embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of another organic light emitting diode provided by an embodiment.
  • the hole blocking layer 14 includes three sub-hole blocking layers, namely a first sub-hole blocking layer 141, a second sub-hole blocking layer 142, and a third sub-hole blocking layer 143.
  • the LUMO energy level of the first sub-hole blocking layer 141 is lower than the LUMO energy level of the second sub-hole blocking layer 142, and both are lower than the LUMO energy level of the third sub-hole blocking layer 143.
  • the material of the first sub-hole blocking layer 141 may be Bphen
  • the material of the second sub-hole blocking layer 142 may be BCP
  • the material of the third sub-hole blocking layer 143 may be BAlq.
  • the LUMO energy level of the third sub-hole blocking layer 143 is lower than the LUMO energy level of the second sub-hole blocking layer 142, and both are lower than the LUMO energy level of the first sub-hole blocking layer 141.
  • the first The material of the first sub-hole blocking layer 141 may be BAlq
  • the material of the second sub-hole blocking layer 142 may be BCP
  • the material of the third sub-hole blocking layer 143 may be Bphen.
  • the first sub-hole blocking layer 141, the second sub-hole blocking layer 142, and the third sub-hole blocking layer 143 may also use other hole blocking layer materials known to those skilled in the art. Not limited.
  • FIG. 1 only shows that the hole blocking layer 14 includes two sub-hole blocking layers by way of example.
  • FIG. 2 shows only the hole blocking layer 14 including three sub-hole blocking layers by way of example.
  • the exemplary description is not a limitation on the organic light emitting diode 10 provided in the embodiment of the present application.
  • the number of layers of the sub-hole blocking layer included in the hole blocking layer 14 may be set according to the actual requirements of the organic light emitting diode 10, which is not limited in the embodiment of the present application.
  • each of the above film layers of the organic light emitting diode 10 can be formed by evaporation, sputtering, inkjet printing, or other film formation methods known to those skilled in the art, which is not limited in the embodiment of the present application.
  • the relative levels of the LUMO and HOMO levels of multiple layers in this paper can be understood as the energy level in the ionized state (the lowest energy level is called the ground state, and the other energy levels are called the excited state.
  • the state of an atomic nucleus, which is no longer attracted by the atomic nucleus, is called an ionized state.
  • the energy level of the ionized state is 0) as the reference energy level, and the energy level closer to the reference energy level is a relatively higher energy level. Energy levels that are farther away are relatively low energy levels.
  • the hole blocking layer 14 by setting the hole blocking layer 14 to include at least two sub hole blocking layers, and the LUMO energy levels of the at least two sub hole blocking layers are sequentially reduced, the LUMO energy levels of the hole blocking layer in the related art can be divided.
  • the number of holes allows more electrons and holes to recombine in the light-emitting layer 13 for emitting light and improves the light-emitting efficiency of the organic light-emitting diode 10; at the same time, since more electrons are recombined, the electrons on the organic layer 13 can be slowed down.
  • the destruction of the film layer with the first electrode 11 and the interface between the adjacent film layers further improves the light emitting efficiency of the organic light emitting diode 10 while increasing the life of the organic light emitting diode 10.
  • FIG. 3 is a schematic diagram of an energy level structure of an organic light emitting diode according to an embodiment.
  • at least two sub-hole blocking layers (the organic light emitting diode 10 shown in FIGS. 2 and 3 include three sub-hole blocking layers along the light-emitting layer 13 in a direction Z1 toward the second electrode 12).
  • the LUMO energy levels of the first sub-hole blocking layer 141, the second sub-hole blocking layer 142, and the third sub-hole blocking layer 143 are sequentially reduced, and at least two sub-hole blocking layers (FIGS. 2 and 2) In FIG.
  • the HOMO energy levels of the first sub-hole blocking layer 141, the second sub-hole blocking layer 142, and the third sub-hole blocking layer 143 are shown in order.
  • the LUMO energy level is lower than the LUMO energy level of the light emitting layer 13.
  • the LUMO energy level 141L of the first sub-hole blocking layer 141 is higher than the LUMO energy level 142L of the second sub-hole blocking layer 142, and the LUMO energy level 142L of the second sub-hole blocking layer 142 is higher than the third sub-space.
  • the LUMO energy level 143L of the hole blocking layer 143; meanwhile, the LUMO energy level 143L of the third sub-hole blocking layer 143 is higher than the Fermi level 12F of the second electrode 12, and the LUMO energy level of the first sub-hole blocking layer 141 141L is lower than the LUMO energy level 13L of the light emitting layer 13.
  • the HOMO level 141H of the first sub-hole blocking layer 141 is higher than the HOMO level 142H of the second sub-hole blocking layer 142, and the HOMO energy level 142H of the second sub-hole blocking layer 142 is higher than the third sub-hole blocking
  • the LUMO energy level of the hole blocking layer is divided into the stepwise changing LUMO energy levels of the three sub-hole blocking layers.
  • the two electrodes 12 are injected into the light-emitting layer 13 through the first sub-hole blocking layer 141, the second sub-hole blocking layer 142, and the third sub-hole blocking layer 143 in this order.
  • holes can be effectively blocked from being transported from the light emitting layer 13 to the second electrode 12 side. Therefore, through the above-mentioned energy level setting, the number of electrons and holes in the light-emitting layer 13 can be increased at the same time.
  • the organic light-emitting diode can be improved. 10 luminous efficiency.
  • the number of electrons that are not recombined is reduced, so that electrons can be reduced to the film layer between the light-emitting layer 13 and the first electrode 11 and to the adjacent film layer.
  • the destructive effect of the interfacial interface slows down the degradation of the performance of the film layer described above, and slows down the degradation of the performance of the interface between adjacent film layers, thereby improving the life of the organic light emitting diode 10.
  • FIG. 4 is a schematic diagram of an energy level structure of another organic light emitting diode provided by an embodiment.
  • at least two sub-hole blocking layers for example, the organic light emitting diode 10 shown in FIG. 4 includes three sub-hole blocking layers,
  • the LUMO energy levels of the first sub-hole blocking layer 141, the second sub-hole blocking layer 142, and the third sub-hole blocking layer 143, respectively, are sequentially reduced, and at least two sub-hole blocking layers (in FIG.
  • the HOMO energy levels of the first sub-hole blocking layer 141, the second sub-hole blocking layer 142, and the third sub-hole blocking layer 143 are sequentially decreased; and the LUMO level of any one of the sub-hole blocking layers The LUMO energy level of the light emitting layer 13 is lower.
  • the LUMO energy level 141L of the first sub-hole blocking layer 141 is higher than the LUMO energy level 142L of the second sub-hole blocking layer 142, and the LUMO energy level 142L of the second sub-hole blocking layer 142 is higher than the third sub-space.
  • the HOMO level 141H of the first sub-hole blocking layer 141 is higher than the HOMO level 142H of the second sub-hole blocking layer 142, and the HOMO energy level 142H of the second sub-hole blocking layer 142 is higher than the third sub-hole blocking
  • the LUMO energy level of the hole blocking layer is divided into three subspaces.
  • the stepwise changing LUMO energy level of the hole blocking layer is sequentially reduced along the direction in which the second electrode 12 is directed to the light emitting layer 13. Therefore, electrons can be easily transferred from the LUMO energy level 141L of the first sub-hole blocking layer 141.
  • the number of electrons and holes in the light-emitting layer 13 can be increased at the same time. Therefore, more electrons and holes can be recombined in the light-emitting layer 13 for light emission, and therefore, the organic light-emitting diode can be improved. 10 luminous efficiency.
  • the number of electrons that are not recombined is reduced, so that electrons can be reduced to the film layer between the light-emitting layer 13 and the first electrode 11 and to the adjacent film layer.
  • the destructive effect of the interfacial interface slows down the degradation of the performance of the film layer described above, and slows down the degradation of the performance of the interface between adjacent film layers, thereby improving the life of the organic light emitting diode 10.
  • the energy level structure of the organic light emitting diode 10 provided in the present application is illustrated in FIG. 3 and FIG. 4 by way of example only.
  • the hole blocking layer includes three sub-hole blocking layers. Definition of the diode 10.
  • the energy level structure of the organic light emitting diode 10 can also be set according to the actual needs of the organic light emitting diode 10, which is not limited in the embodiments of the present application.
  • the energy level difference L1 of the LUMO levels of two adjacent sub-hole blocking layers ranges from L1 ⁇ 0.15eV.
  • the energy level difference L1 of the LUMO energy levels of two adjacent sub-hole blocking layers ranges from L1 ⁇ 0.1eV. In this way, the energy level difference between the LUMO energy levels of two adjacent sub-hole blocking layers can be reduced, which is conducive to increasing the number of electrons in the LUMO energy level 13L of the light-emitting layer 13, and thus is beneficial to improving the life of the organic light-emitting diode 10.
  • the LUMO energy level 13L of the light-emitting layer 13 and at least two sub-hole blocking layers (the first sub-hole blocking layer 141 and the second sub-hole blocking layer 141 in FIG. 3 and FIG. 4)
  • the energy level difference L2 of the LUMO level of the sub-hole blocking layer having the highest LUMO energy level ranges from L2 ⁇ 0.1 eV; among them, LUMO
  • the sub-hole blocking layer having the highest energy level is a sub-hole blocking layer having the LUMO energy level closest to the LUMO energy level of the light emitting layer 13.
  • the embodiment of the present application only exemplarily shows the value of the energy level difference L2 between the LUMO energy level 13L of the light emitting layer 13 and the LUMO energy level of the sub hole blocking layer with the highest LUMO energy level in at least two sub hole blocking layers.
  • the range is L2 ⁇ 0.1eV, which is not a limitation on the organic light emitting diode 10 provided in this embodiment.
  • the LUMO energy level 13L of the light emitting layer 13 and the LUMO energy level of the sub hole blocking layer having the highest LUMO energy level among at least two sub hole blocking layers may be set.
  • the value range of the energy level difference L2 is, for example, L2 ⁇ 0.08eV, or L2 ⁇ 0.05eV, which is not limited in this embodiment.
  • the range of the energy level difference H1 between the HOMO level of the at least one sub-hole blocking layer and the HOMO level 13H of the light emitting layer 13 ranges 0.2eV ⁇ H1 ⁇ 0.5eV.
  • the LUMO energy level 13L of the light-emitting layer 13 can also be understood as the LUMO energy level of the guest material
  • the HOMO energy level 13H of the light-emitting layer 13 can also be understood as the HOMO energy level of the guest material.
  • the embodiment of the present application only exemplarily shows that the energy level difference H1 of the HOMO energy level of the at least one sub-hole blocking layer and the HOMO energy level 13H of the light emitting layer 13 ranges from 0.2eV ⁇ H1 ⁇ 0.5eV, and It is not limited to the organic light emitting diode 10 provided in this embodiment.
  • the value range of the energy level difference H1 between the HOMO energy level of the at least one sub-hole blocking layer and the HOMO energy level 13H of the light emitting layer 13 may be set according to the actual needs of the organic light emitting diode 10, as an example.
  • the value range may be 0.3eV ⁇ H1 ⁇ 0.4eV, or may be 0.35eV ⁇ H1 ⁇ 0.45eV, which is not limited in this embodiment.
  • the thickness T1 of any one of the sub-hole blocking layers ranges from 0 nm ⁇ T1 ⁇ 5 nm.
  • the width of the sub-hole blocking layer in the electron transport direction (which can be understood as the direction from the second electrode 12 to the light-emitting layer 13) can be reduced, thereby reducing electrons.
  • the residence time in the LUMO energy level of each sub-hole blocking layer is beneficial to reduce the loss of electrons in the hole blocking layer, and further facilitates the injection of more electrons into the LUMO energy level 13L of the light emitting layer 13.
  • the embodiment of the present application only exemplarily shows that the thickness T1 of any one of the sub-hole blocking layers ranges from 0 nm ⁇ T1 ⁇ 5 nm, and is not a limitation on the organic light emitting diode 10 provided in this embodiment.
  • the value range of the thickness T1 of the sub-hole blocking layer may be set according to the actual needs of the organic light emitting diode 10. For example, it may be 0nm ⁇ T1 ⁇ 3.5nm, or may be 0nm ⁇ T1 ⁇ 2.5nm, which is not limited in this embodiment.
  • the thickness T2 of the sub-hole blocking layer adjacent to the light-emitting layer 13 ranges from 2 nm ⁇ T2 ⁇ 3 nm.
  • the electron-transport direction of the sub-hole blocking layer immediately adjacent to the light-emitting layer can be reduced (it can be understood that the direction from the second electrode 12 to the light-emitting layer 13) ),
  • the time for electrons to stay in the LUMO energy level of the sub-hole blocking layer immediately adjacent to the light-emitting layer 13, which is beneficial to reducing the loss of electrons in the sub-hole blocking layer immediately adjacent to the light-emitting layer 13, and thus is beneficial to More electrons are injected into the LUMO energy level 13L of the light emitting layer 13.
  • the embodiment of the present application only exemplarily shows that the thickness T2 of the sub-hole blocking layer adjacent to the light emitting layer 13 ranges from 2nm ⁇ T2 ⁇ 3nm, and is not a limitation on the organic light emitting diode 10 provided in this embodiment.
  • the value range of the thickness T2 of the sub-hole blocking layer immediately adjacent to the light-emitting layer 13 may be set according to the actual needs of the organic light-emitting diode 10. For example, it may be 2.3 nm ⁇ T2 ⁇ 2.8 nm, or It may be 2.2 nm ⁇ T2 ⁇ 2.5 nm, which is not limited in this embodiment.
  • the third sub-hole blocking layer 143 is next to the light-emitting layer 13.
  • the third sub-hole blocking layer 143 By setting the third sub-hole blocking layer 143 to have a thin thickness, it can be considered that part of the electrons
  • the LUMO energy level 142L of the second sub-hole blocking layer 142 can be directly transmitted to the LUMO energy level 13L of the light-emitting layer 13, which can increase the equivalent LUMO energy level of the entire hole-blocking layer, thereby reducing the hole-blocking layer and the light-emitting layer.
  • the difference in energy level between them facilitates the transport of electrons from the hole-blocking layer to the light-emitting layer, and therefore helps to increase the number of electrons in the light-emitting layer 13.
  • FIG. 5 is a schematic structural diagram of still another organic light emitting diode provided by an embodiment of the present application.
  • the organic light emitting diode 10 may further include a first carrier functional layer 15 and a second carrier functional layer 16; the first carrier functional layer 15 is located between the first electrode 11 and the light emitting layer 13; The second carrier functional layer 16 is located between the hole blocking layer 14 and the second electrode 12.
  • the first carrier function layer 15 may be a hole-type auxiliary function layer, and may have a multi-layer structure, for example, it may include a hole injection layer, a hole transport layer, and an electron blocking layer.
  • the example provided with the first carrier function layer 15 in FIG. 5 includes a hole injection layer 153, a hole transport layer 152, and an electron blocking layer 151.
  • the second carrier function layer 16 may be an electronic auxiliary function layer, or may have a multi-layer structure, for example, it may include an electron injection layer and an electron transport layer.
  • the exemplary arrangement of the second carrier function layer 16 in FIG. 5 includes an electron injection layer 162 and an electron transport layer 161.
  • the material of the hole injection layer 153 may be copper phthalocyanine (CuPC), titanyl phthalocyanine (TiOPC), 4,4 ′, 4 ”-tris (3-methylphenylaniline) triphenylamine ( m-MTDATA), 4,4 ', 4 "-tri [N- (naphthalene-2-yl) -N-phenyl-amino)] triphenylamine (2T-NANA).
  • CuPC copper phthalocyanine
  • TiOPC titanyl phthalocyanine
  • m-MTDATA 4,4 ', 4 "-tri [N- (naphthalene-2-yl) -N-phenyl-amino)] triphenylamine
  • the material of the hole transport layer 152 may be N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (TPD ), N, N'-diphenyl-N, N '-(1-naphthyl) -1,1'-biphenyl-4,4'-diamine (NPB), poly (9-vinylcarbazole ) (PVK), at least one of.
  • the material of the electron blocking layer 151 may be N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (TCTA) .
  • the material of the electron injection layer 162 may be at least one of lithium fluoride (LiF), yttrium fluoride (YF), magnesium phosphide (MgP), magnesium fluoride (MgF2), and aluminum oxide (Al2O3).
  • LiF lithium fluoride
  • YF yttrium fluoride
  • MgP magnesium phosphide
  • Al2O3 aluminum oxide
  • the material of the electron transport layer 161 may be 8-hydroxyquinoline aluminum (Alq3), tris (2-methyl-8-hydroxyquinoline) (Almq3), 1,3,5-tris (1-phenyl-1H- Benzimidazol-2-yl) benzene (TPBi), 3- (biphenyl-4-yl) -5- (4-tert-butylphenyl) -4-phenyl-4H-1,2,4-tris Azole (TAZ), 1,3-bis [2- (p-tert-butylphenyl) -1,3,4-oxadiazolyl-5] benzene (OXD), 2-biphenyl-5- ( 4-tert-butylphenyl) -1,3,4-diazole (PBD), 2,5-bis (1-naphthyl) -1,3,4-diazole (BND).
  • Alq3 8-hydroxyquinoline aluminum
  • Almq3 1,3,5-tris (1-phen
  • the first carrier function layer 15 and the second carrier function layer 16 may further include materials of a carrier function layer known to those skilled in the art, which are not described in this embodiment and are not limited.
  • the first carrier functional layer 15 and the second carrier functional layer 16 may be formed by evaporation, spray coating, inkjet printing, or other film formation methods known to those skilled in the art.
  • the first carrier functional layer 15 The method for forming the second carrier function layer 16 may be the same or different, which is not limited in the embodiment of the present application.
  • FIG. 6 is a schematic diagram of an energy level structure of another organic light emitting diode according to an embodiment of the present application. 5 and FIG. 6, in the organic light emitting diode 10, the LUMO energy levels of the multiple film layers are in order from low to high: the LUMO energy level 162L of the electron injection layer 162, the LUMO energy level 161L of the electron transport layer 161, The LUMO energy level of the hole blocking layer (including the LUMO energy level 143L of the third sub-hole blocking layer 143, the LUMO energy level 142L of the second sub-hole blocking layer 142, and the LUMO of the first sub-hole blocking layer 141 in this order Energy level 141L), the LUMO energy level 13L of the light-emitting layer 13 and the LUMO energy level 151L of the electron blocking layer 151; wherein the LUMO energy level 152L of the hole transporting layer 152 may be lower than the LUMO energy level 151L of the electron blocking layer 151,
  • the HOMO energy levels of the plurality of film layers are ordered from high to low: HOMO energy level 153H of the hole injection layer 153, HOMO energy level 152H of the hole transport layer 152, and HOMO energy of the electron blocking layer 151.
  • HOMO energy level 161H of the electron transport layer 161 may be higher than the HOMO energy level 143H of the third sub-hole blocking layer 143 and the electron injection layer 162
  • the HOMO energy level 162H may be lower than the HOMO energy level 161H of the electron transport layer 161; the Fermi level 11F of the first electrode 11 is higher than the HOMO energy level 153H of the hole injection layer 153.
  • the number of electrons and holes in the light emitting layer 13 can be increased, so that more electrons and holes are recombined in the light emitting layer 13 and used. Since light emission is achieved, the light emission efficiency of the organic light emitting diode 10 can be improved. At the same time, since more electrons are recombined in the light-emitting layer 13, it is possible to reduce the damaging effect of the electrons on the film layer between the light-emitting layer 13 and the first electrode 11 and the interface between adjacent film layers, and slow down the film. The degradation of the layer performance and the degradation of the interface performance between adjacent film layers are slowed down, thereby increasing the life of the organic light emitting diode 10.
  • the value range of the work function 12F of the second electrode 12 may be
  • the range of LUMO energy level 161L can be 2.7eV ⁇
  • the value range of the LUMO energy level 143L of the third sub-hole blocking layer 143 may be 2.7eV ⁇
  • the value range of the LUMO energy level 142L of the second sub-hole blocking layer 142 may be 2.7eV ⁇
  • each film layer is merely an exemplary description of the organic light emitting diode 10 provided by the embodiment of the present application, and is not limited. In other embodiments, the energy level range of each film layer of the organic light emitting diode 10 can be set according to the actual needs of the organic light emitting diode 10, which is not limited in the embodiments of the present application.
  • the embodiment of the present application exemplarily shows a comparison table of the light-emitting characteristics between a group of OLEDs provided by the related technology and the OLED provided by the technical solution of the present application, see Table 1.
  • the device D1 represents the organic light emitting diode provided by the related technology
  • the device D2 represents the organic light emitting diode provided by the technical solution of this application.
  • the similarities between the device D1 and the device D2 include: the material of the first electrode is ITO, and the thickness is 10 nm. Function: 4.3eV; thickness of hole injection layer is 10nm; thickness of hole transport layer is 120nm; thickness of electron blocking layer is 5nm; thickness of light emitting layer is 20nm; thickness of electron transport layer is 30nm; thickness of electron injection layer It is 1 nm; the material of the second electrode is a metal electrode with a thickness of 13-20 nm.
  • the difference between device D1 and device D2 is that the hole blocking layer of device D1 is a single-layer structure with a thickness of 5 nm, the position of the LUMO level is 2.8 eV, and the position of the HOMO level is 6.1 eV; the hole of the device D2
  • the blocking layer includes two sub-hole blocking layers, namely a first sub-hole blocking layer and a second sub-hole blocking layer.
  • the first sub-hole blocking layer is located between the light emitting layer and the second sub-hole blocking layer.
  • the thickness of the first sub-hole blocking layer is 3 nm, the position of the LUMO level is 2.8 eV, and the position of the HOMO level is 6.1 eV.
  • the thickness of the second sub-hole blocking layer is 2 nm, and the position of the LUMO level is 2.7 eV.
  • the position of the HOMO energy level is 6.0 eV.
  • the hole blocking layer includes at least two sub-holes. Barrier layer, the performance of device D1 and device D2 in terms of operating voltage, current efficiency, lumen efficiency, color coordinate, peak position and blue light factor are all consistent; in terms of life, the 120h life of device D1 is increased to that of device D2 180h life. Therefore, compared with the related art, the technical solution of the present application can improve the life from 120h to 180h, that is, the life is increased by 50%, on the premise that other light emitting characteristics of the organic diode are basically unchanged.
  • the comparison between the device D1 and the device D2 is only an exemplary description of the organic light emitting diode provided by the embodiment of the present application, and is not a limitation.
  • FIG. 7 is a schematic structural diagram of a display panel provided by an embodiment of the present application.
  • the display panel 20 includes: a base substrate 21 and a plurality of pixel units 22 arranged in an array on one side of the base substrate 21; wherein the pixel units 22 include any one of the organic light-emitting devices provided in the foregoing embodiments. diode.
  • the display panel 20 provided in the embodiment of the present application includes any one of the organic light emitting diodes described above. Therefore, the display panel 20 also has the beneficial effects of the organic light emitting diodes described above.
  • the base substrate 21 may be an array substrate for driving the pixel unit 22 to emit light.
  • the row direction X and the column direction Y are shown in FIG. 7 (the plane on which the row direction X and the column direction Y are shown in FIG. 7 is the plane on which the substrate 21 is located;
  • the direction Z1 from the light-emitting layer 13 to the second electrode 12 and the direction Z2 from the second electrode 12 to the light-emitting layer 13 are perpendicular to the plane on which the above-mentioned substrate 21 is located), and are shown in 7 columns and 4 rows.
  • each pixel unit 22 may include a blue sub-pixel 221, a red sub-pixel 222, and a green sub-pixel 223; at the same time, the sub-pixels in the plurality of pixel units 22 are aligned in the column direction Y according to the blue sub-pixels.
  • the order of the pixels 221, the red sub-pixel 222, and the green sub-pixel 223 is merely an exemplary description of the display panel 20 provided by the embodiment of the present application, and is not a limitation.
  • the array arrangement of the pixel units 22 and the number of blue sub-pixels 221, red sub-pixels 222, and green sub-pixels 223 in each pixel unit 22 may be set according to the actual needs of the display panel 20. And the arrangement manner is not limited in the embodiment of the present application.
  • the embodiment of the present application does not limit the specific type of the display panel 20, and the technical solution proposed in the embodiment of the present application can be applied to any display panel involving electron and hole transport processes, and the exemplary display panel may be an OLED display panel 2.

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Abstract

一种有机发光二极管（10），包括：第一电极（11）、第二电极（12）、发光层（13）和空穴阻挡层（14）；第一电极与第二电极相对设置；发光层位于第一电极与第二电极之间；空穴阻挡层位于发光层与第二电极之间；其中，空穴阻挡层包括堆叠的至少两层子空穴阻挡层，至少两层子空穴阻挡层的LUMO能级依次降低。

Description

有机发光二极管和显示面板
本公开要求在2018年09月18日提交中国专利局、申请号为201821525618.X的中国专利申请的优先权，该申请的全部内容通过引用结合在本公开中。
技术领域
本申请涉及显示技术领域，具体涉及一种有机发光二极管和显示面板。
背景技术
有机发光二极管(Organic Light-Emitting Diode,OLED)利用自发光的发光机制，不需要背光源，将其应用于显示面板和显示装置时，显示面板和显示装置的整体厚度较薄，有利于实现显示面板和显示装置的轻薄化设计。同时，有机发光二极管具有显示亮度高、视角广以及响应速度快等优势。
然而，现有的有机发光二极管的寿命较短。
发明内容
本申请提供一种有机发光二极管和显示面板，以提高有机发光二极管的寿命。
本申请提供了一种有机发光二极管，该有机发光二极管包括：第一电极、第二电极、发光层和空穴阻挡层；
所述第一电极与所述第二电极相对设置；
所述发光层位于所述第一电极与所述第二电极之间；
所述空穴阻挡层位于所述发光层与所述第二电极之间；
其中，所述空穴阻挡层包括堆叠的至少两层子空穴阻挡层，所述至少两层 子空穴阻挡层的LUMO能级依次降低。
进一步地，沿所述发光层指向所述第二电极的方向，所述至少两层子空穴阻挡层的LUMO能级依次降低，所述至少两层子空穴阻挡层的HOMO能级依次降低；
且任意一层所述子空穴阻挡层的LUMO能级低于所述发光层的LUMO能级。
进一步地，沿所述第二电极指向所述发光层的方向，所述至少两层子空穴阻挡层的LUMO能级依次降低，所述至少两层子空穴阻挡层的HOMO能级依次降低；
且任意一层所述子空穴阻挡层的LUMO能级低于所述发光层的LUMO能级。
进一步地，相邻两层所述子空穴阻挡层的LUMO能级的能级差L1的取值范围为L1≤0.15eV。
进一步地，相邻两层所述子空穴阻挡层的LUMO能级的能级差L1的取值范围为L1≤0.1eV。
进一步地，所述发光层的LUMO能级与所述至少两层子空穴阻挡层中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围为L2≤0.1eV；
其中，所述LUMO能级最高的子空穴阻挡层为LUMO能级与所述发光层的LUMO能级最接近的子空穴阻挡层。
进一步地，所述发光层的LUMO能级与所述至少两层子空穴阻挡层中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围为L2≤0.08eV。
进一步地，所述空穴阻挡层中，至少一层所述子空穴阻挡层的HOMO能级与所述发光层的HOMO能级的能级差H1的取值范围为0.2eV≤H1≤0.5eV。
进一步地，所述空穴阻挡层中，至少一层所述子空穴阻挡层的HOMO能级与所述发光层的HOMO能级的能级差H1的取值范围为0.3eV≤H1≤0.4eV。
进一步地，所述任意一层所述子空穴阻挡层的厚度T1的取值范围为0nm＜T1≤5nm。
进一步地，所述任意一层所述子空穴阻挡层的厚度T1的取值范围为0nm＜T1≤3.5nm。
进一步地，紧邻所述发光层的所述子空穴阻挡层的厚度T2的取值范围为2nm≤T2≤3nm。
进一步地，紧邻所述发光层的所述子空穴阻挡层的厚度T2的取值范围为2.3nm≤T2≤2.8nm。
进一步地，还包括第一载流子功能层和第二载流子功能层；
所述第一载流子功能层位于所述第一电极与所述发光层之间；
所述第二载流子功能层位于所述空穴阻挡层与所述第二电极之间。
本申请还提供了一种显示面板，该显示面板包括衬底基板，以及位于所述衬底基板一侧呈阵列排布的多个像素单元；
其中，所述像素单元包括本申请提供的上述任一种有机发光二极管。
附图说明
图1是一实施例提供的一种有机发光二极管的结构示意图；
图2是一实施例提供的另一种有机发光二极管的结构示意图；
图3是一实施例提供的一种有机发光二极管的能级结构示意图；
图4是一实施例提供的另一种有机发光二极管的能级结构示意图；
图5是一实施例提供的又一种有机发光二极管的结构示意图；
图6是一实施例提供的又一种有机发光二极管的能级结构示意图；
图7是一实施例提供的一种显示面板的结构示意图。
具体实施方式
相关技术中，性能优异的有机发光二极管的发光层材料为偏向电子传输型的材料，有机发光二极管还包括位于发光层两侧的第一电极和第二电极，示例性的，第一电极可为阳极，第二电极可为阴极。当给有机发光二极管提供驱动电流时，电子由第二电极注入发光层，空穴由第一电极注入发光层，由于发光层的材料为偏向电子传输型的材料，因此，该发光层的材料利于电子的传输，从而大量的电子到达发光层，由此可提升有机发光二极管的电流效率。但是，当发光层中电子的数量多于空穴的数量较多时，过多的电子无法被复合，该部分无法被复合的电子被传输至发光层与第一电极之间的膜层中，会破坏这些膜层的性能以及破坏相邻的膜层之间的界面，导致有机发光二极管中发光层与第一电极之间的膜层性能衰退，以及导致发光层与第一电极之间的多个膜层中相邻膜层之间的界面被破坏，由此导致有机发光二极管的寿命下降，即有机发光二极管的寿命较短。
针对上述问题，本申请实施例提出一种有机发光二极管，以提高有机发光二极管的寿命。
图1是一实施例提供的一种有机发光二极管的结构示意图。参照图1，该有机发光二极管10包括：第一电极11、第二电极12、发光层13和空穴阻挡层14；第一电极11与第二电极12相对设置；发光层13位于第一电极11与第二电极12之间；空穴阻挡层14位于发光层13与第二电极12之间；其中，空穴阻挡层14包括堆叠的至少两层子空穴阻挡层(示例性的，图1中示出的有机发光二极管10中，空穴阻挡层14包括两层子空穴阻挡层，分别以第一子空穴阻挡层141和第二子空穴阻挡层142示出，且第一子空穴阻挡层141位于第二子空穴阻挡层142靠近发光层13的一侧)，至少两层子空穴阻挡层(图1中以第一子空穴 阻挡层141和第二子空穴阻挡层142示出)的LUMO能级依次降低。
其中，第一电极11可为阳极，示例性的，第一电极11的材料可为铟锡氧化物(ITO)。第二电极12可为阴极，示例性的，第二电极12的材料可为金属材料，例如铝(Al)、金(Au)、银(Ag)或包括Ag的金属合金等功函数较低的导电材料。发光层13可包括主体材料和客体材料，示例性的，主体材料可为8-羟基喹啉铝(Alq3)、9,10-二(1-萘基)蒽(ADN)、4,4'-双(9H-咔唑-9-基)联苯(CBP)；客体材料可为2-叔丁基-4-(二氰基亚甲基)-6-[2-(1,1,7,7-四甲基久洛尼定-9-基)乙烯基]-4H-吡喃(DCJBT)、N,N'-二甲基喹吖啶酮(DMQA)、N,N'-二丁基喹吖啶酮(DBQA)、香豆素545T(C545T)、5,12-二丁基-1,3,8,10-四甲基喹吖啶酮(TMDBQA)、4,4'-双(9-乙基-3-咔唑乙烯基)-1,1'-联苯(BCzVBi)、4,4'-双[4-(二对甲苯基氨基)苯乙烯基]联苯(DPAVBi)、1,4-双[4-(二对甲苯氨基)苯乙烯基]苯(DPAVB)、3,3'-(1,4-苯基二-2,1-乙烯基)二(9-乙基-9H-咔唑)(BCZVB)。上述材料仅为示例性的说明，本申请对第一电极11和第二电极12的材料不作限定。
其中，有机发光二极管10的发光原理主要包括载流子(载流子可为电子或空穴)注入、载流子传输、载流子复合和激子退激发光四个过程。具体的，当给有机发光二极管10施加一定的电压(也可理解为提供驱动电流)时，第一电极11(阳极)的空穴和第二电极12(阴极)的电子分别注入到发光层13中(此为载流子注入过程)；注入的电子和空穴在电场的作用下传输(此为载流子传输过程)；电子和空穴通过库伦作用在发光层13中复合，产生激子(此为载流子复合过程)；激子由激发态回到基态的同时释放光子发光(此为激子退激发光过程)。
其中，空穴阻挡层14设置于发光层13和第二电极12(阴极)之间，其作 用主要体现在两个方面：一方面，可阻挡空穴由发光层13向第二电极12侧传输，从而可将较多的空穴限制在发光层13中；另一方面，有利于电子由第二电极12向发光层13传输，从而可增加发光层13中电子的数量。空穴阻挡层14的材料可为((1,1’-二苯基)-4-olato)双(2-甲基-8-羟基喹啉NI，08)铝(BAlq)、2,9-二甲基-4,7-二苯基-1,10-菲咯啉(BCP)、二[2-((氧代)二苯基膦基)苯基]醚(DPEPO)、4,7-二苯基-1,10-菲罗啉(Bphen)或其他本领域技术人员可知的空穴阻挡层材料，本申请实施例对此不作限定。
通过设置空穴阻挡层14包括至少两层子空穴阻挡层，两层子空穴阻挡层采用LUMO能级位置不同的空穴阻挡层材料，可将相关技术中单层的空穴阻挡层的LUMO能级划分为至少两个能级差较小的LUMO能级。由于较小的LUMO能级差更有利于电子的传输，因此通过上述设置，可使较多的电子注入到发光层13中。同时，由于空穴阻挡层14的传输电子与阻挡空穴的作用是相辅相成的，即当空穴阻挡层14的传输电子的作用越强，该空穴阻挡层14阻挡空穴的作用也越强。因此，上述设置还可以有效阻挡空穴由发光层13向第二电极12侧传输，从而，较多的空穴被限制在发光层13中。综上所述，通过上述设置，可同时提升发光层13中电子和空穴的数量，从而，较多的电子和空穴在发光层13中复合，用于发光，因此可提升有机发光二极管10的发光效率。同时，由于较多的电子在发光层13中被复合，因此，可减少电子对发光层13与第一电极11之间的膜层以及相邻膜层之间的界面的破坏作用，减缓上述膜层性能的衰退，以及减缓相邻膜层之间的界面的性能的衰退，从而可提升有机发光二极管10的寿命。
示例性的，参照图1，空穴阻挡层14包括第一子空穴阻挡层141和第二子空穴阻挡层142，其中，第一子空穴阻挡层141的LUMO能级低于第二子空穴阻挡层142的LUMO能级，该结构中，第一子空穴阻挡层141的材料可为Bphen， 第二子空穴阻挡层142的材料可为BCP。或者，第二子空穴阻挡层142的LUMO能级低于第一子空穴阻挡层141的LUMO能级，此时，第一子空穴阻挡层141的材料可为BCP，第二子空穴阻挡层142的材料可为Bphen。当然，第一子空穴阻挡层141和第二子空穴阻挡层142还可采用其他本领域技术人员可知的空穴阻挡层材料，本申请实施例对此不作限定。
示例性的，图2是一实施例提供的另一种有机发光二极管的结构示意图。参照图2，空穴阻挡层14包括三层子空穴阻挡层，分别为第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143。其中，第一子空穴阻挡层141的LUMO能级低于第二子空穴阻挡层142的LUMO能级，且均低于第三子空穴阻挡层143的LUMO能级，该结构中，第一子空穴阻挡层141的材料可为Bphen，第二子空穴阻挡层142的材料可为BCP，第三子空穴阻挡层143的材料可为BAlq。或者，第三子空穴阻挡层143的LUMO能级低于第二子空穴阻挡层142的LUMO能级，且均低于第一子空穴阻挡层141的LUMO能级，此时，第一子空穴阻挡层141的材料可为BAlq，第二子空穴阻挡层142的材料可为BCP，第三子空穴阻挡层143的材料可为Bphen。当然，第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143还可采用其他本领域技术人员可知的空穴阻挡层材料，本申请实施例对此不作限定。
图1中仅示例性的示出了空穴阻挡层14包括两层子空穴阻挡层，图2中仅示例性的示出了空穴阻挡层14包括三层子空穴阻挡层，均为示例性的说明，而非对本申请实施例提供的有机发光二极管10的限定。在其他实施方式中，可根据有机发光二极管10的实际需求设置空穴阻挡层14包括的子空穴阻挡层的层数，本申请实施例对此不作限定。
其次，有机发光二极管10的上述每个膜层均可采用蒸镀、溅射、喷墨打印 或本领域技术人员可知的其他成膜方式形成，本申请实施例对此不作限定。
此外，本文中多个膜层的LUMO能级和HOMO能级的相对高低可理解为，以电离态的能级(能量最低的能级叫做基态，其他能级叫做激发态。当电子“远离”原子核，不再受原子核的吸引力的状态叫做电离态，电离态的能级为0)为基准能级，与该基准能级距离较近的能级为相对较高的能级，与该基准能级距离较远的能级为相对较低的能级。
本申请实施例通过设置空穴阻挡层14包括至少两层子空穴阻挡层，且至少两层子空穴阻挡层的LUMO能级依次降低，可将相关技术中空穴阻挡层的LUMO能级划分为至少两个能级差较小的LUMO能级，从而有利于电子传输至发光层13，且可有效阻挡空穴由发光层13传输至第二电极12侧，从而可提升发光层13中电子和空穴的数量，使较多的电子和空穴在发光层13中复合，用于发光，提高有机发光二极管10的发光效率；同时，由于较多的电子被复合，可减缓电子对有机层13与第一电极11之间的膜层以及其中相邻膜层之间的界面的破坏，进而在提升有机发光二极管10的发光效率的同时，可提高有机发光二极管10的寿命。
在一实施例中，图3是一实施例提供的一种有机发光二极管的能级结构示意图。结合图2和图3，沿发光层13指向第二电极12的方向Z1，至少两层子空穴阻挡层(图2和图3中示出的有机发光二极管10包括三层子空穴阻挡层，以第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143示出)的LUMO能级依次降低，至少两层子空穴阻挡层(图2和图3中以第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143示出)的HOMO能级依次降低；且任意一层子空穴阻挡层的LUMO能级低于发光层13的LUMO能级。
其中，第一子空穴阻挡层141的LUMO能级141L高于第二子空穴阻挡层142 的LUMO能级142L，第二子空穴阻挡层142的LUMO能级142L高于第三子空穴阻挡层143的LUMO能级143L；同时，第三子空穴阻挡层143的LUMO能级143L高于第二电极12的费米能级12F，第一子空穴阻挡层141的LUMO能级141L低于发光层13的LUMO能级13L。第一子空穴阻挡层141的HOMO能级141H高于第二子空穴阻挡层142的HOMO能级142H，第二子空穴阻挡层142的HOMO能级142H高于第三子空穴阻挡层143的HOMO能级143H；同时，第一子空穴阻挡层141的HOMO能级141H低于发光层13的HOMO能级13H，发光层13的HOMO能级13H低于第一电极11的费米能级11F。
如此设置，将空穴阻挡层的LUMO能级划分为三个子空穴阻挡层的阶梯状变化的LUMO能级，通过降低相邻膜层之间的LUMO能级差，可使较多的电子由第二电极12，依次通过第一子空穴阻挡层141、第二子空穴阻挡层142以及第三子空穴阻挡层143，注入到发光层13中。同时，通过设置三层子空穴阻挡层，还可有效阻挡空穴由发光层13传输至第二电极12侧。由此，通过上述能级设置，可同时提升发光层13中电子和空穴的数量，从而，较多的电子和空穴可在发光层13中复合，用于发光，因此可提升有机发光二极管10的发光效率。同时，由于较多的电子在发光层13中被复合，因此，未被复合的电子的数量减少，从而可减少电子对发光层13与第一电极11之间的膜层以及相邻膜层之间的界面的破坏作用，减缓上述膜层性能的衰退，以及减缓相邻膜层之间的界面的性能的衰退，从而可提升有机发光二极管10的寿命。
在一实施例中，图4是一实施例提供的另一种有机发光二极管的能级结构示意图。参照图4，沿第二电极12指向发光层13的方向Z2，至少两层子空穴阻挡层(示例性的，图4中示出的有机发光二极管10中包括三层子空穴阻挡层，分别以第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143 示出)的LUMO能级依次降低，至少两层子空穴阻挡层(图4中以第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143示出)的HOMO能级依次降低；且任意一层子空穴阻挡层的LUMO能级低于发光层13的LUMO能级。
其中，第一子空穴阻挡层141的LUMO能级141L高于第二子空穴阻挡层142的LUMO能级142L，第二子空穴阻挡层142的LUMO能级142L高于第三子空穴阻挡层143的LUMO能级143L；同时，第一子空穴阻挡层141的LUMO能级141L高于第二电极12的费米能级12F，第一子空穴阻挡层141的LUMO能级141L低于发光层13的LUMO能级13L。第一子空穴阻挡层141的HOMO能级141H高于第二子空穴阻挡层142的HOMO能级142H，第二子空穴阻挡层142的HOMO能级142H高于第三子空穴阻挡层143的HOMO能级143H；同时，第三子空穴阻挡层143的HOMO能级143H低于发光层13的HOMO能级13H，发光层13的HOMO能级13H低于第一电极11的费米能级11F。
如此设置，虽然第三子空穴阻挡层143的LUMO能级143L与发光层13的LUMO能级13L之间的能级差较大，但是，由于空穴阻挡层的LUMO能级划分为三个子空穴阻挡层的阶梯状变化的LUMO能级，且沿第二电极12指向发光层13的方向Z2依次降低，因此，电子非常容易地可从第一子空穴阻挡层141的LUMO能级141L传输至第三子空穴阻挡层143的LUMO能级143L，从而大量的电子在第三子空穴阻挡层143的LUMO能级143L聚集；因此，电子由第三子空穴阻挡层143的LUMO能级143L传输至发光层13的LUMO能级13L时，电子传输的基数较大，因此，仍存在较多的电子注入到发光层13中。同时，通过设置三层子空穴阻挡层，还可有效阻挡空穴由发光层13传输至第二电极12侧。由此，通过上述能级设置，可同时提升发光层13中电子和空穴的数量，从而，较多的电子和空穴可在发光层13中复合，用于发光，因此可提升有机发光二极管10的发光效率。 同时，由于较多的电子在发光层13中被复合，因此，未被复合的电子的数量减少，从而可减少电子对发光层13与第一电极11之间的膜层以及相邻膜层之间的界面的破坏作用，减缓上述膜层性能的衰退，以及减缓相邻膜层之间的界面的性能的衰退，从而可提升有机发光二极管10的寿命。
图3和图4中仅示例性的以空穴阻挡层包括三层子空穴阻挡层为例示出了本申请提供的有机发光二极管10的能级结构，而并非对本申请实施例提出的有机发光二极管10的限定。在其他实施方式中，有机发光二极管10的能级结构还可以根据有机发光二极管10的实际需求设置，本申请实施例对此不作限定。
在一实施例中，继续参照图3或图4，相邻两层子空穴阻挡层的LUMO能级的能级差L1的取值范围为L1≤0.15eV。
如此设置，可在空穴阻挡层14的子空穴阻挡层中有效传输电子，从而有利于增加发光层13的LUMO能级13L中电子的数量。
在一实施例中，相邻两层子空穴阻挡层的LUMO能级的能级差L1的取值范围为L1≤0.1eV。如此设置，可降低相邻两层子空穴阻挡层的LUMO能级的能级差，从而有利于增加发光层13的LUMO能级13L中电子的数量，进而有利于提升有机发光二极管10的寿命。
在一实施例中，继续参照图3或图4，发光层13的LUMO能级13L与至少两层子空穴阻挡层(图3和图4中以第一子空穴阻挡层141、第二子空穴阻挡层142和第三子空穴阻挡层143示出)中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围为L2≤0.1eV；其中，LUMO能级最高的子空穴阻挡层为LUMO能级与发光层13的LUMO能级最接近的子空穴阻挡层。
如此设置，可使电子由空穴阻挡层14有效传输至发光层13，同样有利于增加发光层13的LUMO能级13L中电子的数量。
本申请实施例仅示例性的示出了发光层13的LUMO能级13L与至少两层子空穴阻挡层中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围为L2≤0.1eV，而并非对本实施例提供的有机发光二极管10的限定。在其他实施方式中，可根据有机发光二极管10的实际需求，设置发光层13的LUMO能级13L与至少两层子空穴阻挡层中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围，示例性的，可为L2≤0.08eV，或者可为L2≤0.05eV，本实施例对此不作限定。
在一实施例中，继续参照图3或图4，空穴阻挡层14中，至少一层子空穴阻挡层的HOMO能级与发光层13的HOMO能级13H的能级差H1的取值范围为0.2eV≤H1≤0.5eV。
如此设置，通过增大发光层13的HOMO能级13H与至少一层子空穴阻挡层的HOMO能级的能级差，可增大空穴由发光层13传输至空穴阻挡层14的难度，即减少了由发光层13传输至空穴阻挡层14的数量，因此可将较多的空穴限制在发光层13中，从而有利于增加发光层13中空穴的数量。
当发光层13由主体材料和客体材料构成时，发光层13的LUMO能级13L也可以理解为客体材料的LUMO能级，发光层13的HOMO能级13H也可以理解为客体材料的HOMO能级。
本申请实施例仅示例性的示出了至少一层子空穴阻挡层的HOMO能级与发光层13的HOMO能级13H的能级差H1的取值范围为0.2eV≤H1≤0.5eV，而并非对本实施例提供的有机发光二极管10的限定。在其他实施方式中，可根据有机发光二极管10的实际需求，设置至少一层子空穴阻挡层的HOMO能级与发光层13的HOMO能级13H的能级差H1的取值范围，示例性的，该取值范围可为0.3eV≤H1≤0.4eV，或者可为0.35eV≤H1≤0.45eV，本实施例对此不作限定。
在一实施例中，继续参照图3或图4，任意一层子空穴阻挡层的厚度T1的取值范围为0nm＜T1≤5nm。
如此，通过设置子空穴阻挡层具有较薄的厚度，可以减少子空穴阻挡层在电子传输方向(可理解为由第二电极12指向发光层13的方向)上的宽度，从而减少了电子在每一层子空穴阻挡层的LUMO能级中停留的时间，有利于减少电子在空穴阻挡层的损耗，进而有利于较多的电子注入到发光层13的LUMO能级13L中。此外，通过设置厚度较薄的子空穴阻挡层，还有利于减少空穴阻挡层的厚度，从而降低有机发光二极管10的整体厚度，将有机发光二极管10应用于显示面板或显示装置时，有利于显示面板或显示装置的轻薄化设计。
本申请实施例仅示例性的示出了任意一层子空穴阻挡层的厚度T1的取值范围为0nm＜T1≤5nm，而并非对本实施例提供的有机发光二极管10的限定。在其他实施方式中，可根据有机发光二极管10的实际需求，设置子空穴阻挡层的厚度T1的取值范围，示例性的，可为0nm＜T1≤3.5nm，或者可为0nm＜T1≤2.5nm，本实施例对此不作限定。
在一实施例中，紧邻发光层13的子空穴阻挡层的厚度T2的取值范围为2nm≤T2≤3nm。
如此，通过设置紧邻发光层13的子空穴阻挡层具有较薄的厚度，可以减少紧邻发光层的子空穴阻挡层在电子传输方向(可理解为由第二电极12指向发光层13的方向)上的宽度，从而减少了电子在紧邻发光层13的子空穴阻挡层的LUMO能级中停留的时间，有利于减少电子在紧邻发光层13的子空穴阻挡层的损耗，进而有利于较多的电子注入到发光层13的LUMO能级13L中。
本申请实施例仅示例性的示出了紧邻发光层13的子空穴阻挡层的厚度T2的取值范围为2nm≤T2≤3nm，而并非对本实施例提供的有机发光二极管10的限 定。在其他实施方式中，可根据有机发光二极管10的实际需求，设置紧邻发光层13的子空穴阻挡层的厚度T2的取值范围，示例性的，可为2.3nm≤T2≤2.8nm，或者可为2.2nm≤T2≤2.5nm，本实施例对此不作限定。
结合图4示出的有机发光二极管10的能级结构示意图，第三子空穴阻挡层143与发光层13紧邻，通过设置第三子空穴阻挡层143具有较薄的厚度，可认为部分电子可由第二子空穴阻挡层142的LUMO能级142L直接传输到发光层13的LUMO能级13L，可提高整个空穴阻挡层的等效LUMO能级，从而可减少空穴阻挡层与发光层之间的能级差，有利于电子由空穴阻挡层传输至发光层，因此，有利于提升发光层13中电子的数量。
在一实施例中，图5是本申请实施例提供的又一种有机发光二极管的结构示意图。参照图5，该有机发光二极管10还可包括第一载流子功能层15和第二载流子功能层16；第一载流子功能层15位于第一电极11与发光层13之间；第二载流子功能层16位于空穴阻挡层14与第二电极12之间。
其中，第一载流子功能层15可为空穴型的辅助功能层，可以具有多层结构，例如可包括空穴注入层、空穴传输层以及电子阻挡层。图5中示例性的设置第一载流子功能层15包括空穴注入层153、空穴传输层152和电子阻挡层151。第二载流子功能层16可为电子型的辅助功能层，也可以具有多层结构，例如可以包括电子注入层和电子传输层。图5中示例性的设置第二载流子功能层16包括电子注入层162和电子传输层161。
示例性的，空穴注入层153的材料可为酞氰铜(CuPC)、酞菁氧钛(TiOPC)、4,4’,4”-三(3-甲基苯基苯胺基)三苯胺(m-MTDATA)、4,4',4”–三[N-(萘-2-基)-N-苯基-氨基)]三苯胺(2T-NANA)中的至少一种。空穴传输层152的材料可为N,N'-二苯基-N,N'-二(3-甲基苯基)-1,1'-联苯-4,4'-二胺(TPD)、N,N'- 二苯基-N,N'-(1-萘基)-1,1'-联苯-4,4'-二胺(NPB)、聚(9-乙烯基咔唑)(PVK)、中的至少一种。电子阻挡层151的材料可为N,N'-二苯基-N,N'-二(3-甲基苯基)-1,1'-联苯-4,4'-二胺(TCTA)。电子注入层162的材料可为氟化锂(LiF)、氟化钇(YF)、磷化镁(MgP)、氟化镁(MgF2)、氧化铝(Al2O3)中的至少一种。电子传输层161的材料可为8-羟基喹啉铝(Alq3)、三(2-甲基-8-羟基喹啉)(Almq3)、1,3,5-三(1-苯基-1H-苯并咪唑-2-基)苯(TPBi)、3-(联苯-4-基)-5-(4-叔丁基苯基)-4-苯基-4H-1,2,4-三唑(TAZ)、1,3-二[2-(对－叔丁基苯基)-1,3,4-恶二唑基-5]苯(OXD)、2-联苯基-5-(4-叔丁基苯基)-1,3,4-二唑(PBD)、2,5-二(1-萘基)-1,3,4-二唑(BND)中的至少一种。
第一载流子功能层15和第二载流子功能层16还可包括本领域技术人员可知的载流子功能层材料，本申请实施例对此不再赘述，也不作限定。第一载流子功能层15和第二载流子功能层16的形成方式可包括蒸镀、喷涂、喷墨打印或本领域技术人员可知的其他成膜方式，第一载流子功能层15和第二载流子功能层16的形成方式可相同，可不同，本申请实施例对此不作限定。
在一实施例中，图6是本申请实施例提供的又一种有机发光二极管的能级结构示意图。结合图5和图6，有机发光二极管10中，多个膜层的LUMO能级由低到高排序依次为：电子注入层162的LUMO能级162L、电子传输层161的LUMO能级161L、空穴阻挡层的LUMO能级(包括依次排列的第三子空穴阻挡层143的LUMO能级143L、第二子空穴阻挡层142的LUMO能级142L和第一子空穴阻挡层141的LUMO能级141L)、发光层13的LUMO能级13L以及电子阻挡层151的LUMO能级151L；其中，空穴传输层152的LUMO能级152L可低于电子阻挡层151的LUMO能级151L，空穴注入层153的LUMO能级153L可高于空穴传输层152的LUMO能级152L；电子注入层162的LUMO能级162L高于第二电极12的费米能级12F。 由此，当给有机发光二极管10提供驱动电流时，电子由第二电极12F侧传输并注入发光层13中，同时，由于电子阻挡层151的LUMO能级151L与发光层13的LUMO能级13L之间的能级差较大，因此电子不容易越过电子阻挡层151的LUMO能级，从而较多的电子被限制在发光层13中，从而可提升发光层13中电子的数量。
有机发光二极管10中，多个膜层的HOMO能级由高到低排序依次为：空穴注入层153的HOMO能级153H、空穴传输层152的HOMO能级152H、电子阻挡层151的HOMO能级151H、发光层13的HOMO能级13H、空穴阻挡层的HOMO能级(包括依次排列的第一子空穴阻挡层141的HOMO能级141H、第二子空穴阻挡层142的HOMO能级142H和第三子空穴阻挡层143H的HOMO能级)；其中，电子传输层161的HOMO能级161H可高于第三子空穴阻挡层143的HOMO能级143H，电子注入层162的HOMO能级162H可低于电子传输层161的HOMO能级161H；第一电极11的费米能级11F高于空穴注入层153的HOMO能级153H。由此，当给有机发光二极管10提供驱动电流时，空穴由第一电极11侧传输并注入发光层13中，通过设置空穴阻挡层的HOMO能级与发光层13的HOMO能级具有较大的能级差，可阻挡空穴由发光层13向第二电极12侧传输，从而较多的空穴被限制在发光层13中，因此可提升发光层13中空穴的数量。
由此，通过上述有机发光二极管10中LUMO能级与HOMO能级的设置，可提升发光层13中电子和空穴的数量，从而，较多的电子和空穴在发光层13中复合，用于发光，因此可提升有机发光二极管10的发光效率。同时，由于较多的电子在发光层13中被复合，因此，可减少电子对发光层13与第一电极11之间的膜层以及相邻膜层之间的界面的破坏作用，减缓上述膜层性能的衰退，以及减缓相邻膜层之间的界面的性能的衰退，从而提升有机发光二极管10的寿命。
示例性的，第二电极12的功函数12F的取值范围可为|12F|≤4.3eV；电子注入层162的功函数162F的取值范围为|162F|≤3.6e；电子传输层161的LUMO能级161L的取值范围可为2.7eV≤|161L|≤3.2eV，优选为3.0eV，其HOMO能级161H的取值范围可为5.9eV≤|161H|≤6.1eV，优选为6.0eV；第三子空穴阻挡层143的LUMO能级143L的取值范围可为2.7eV≤|143L|≤3.2eV，优选为2.9eV，其HOMO能级143H的取值范围可为5.9eV≤|143H|≤6.4eV，优选为6.20eV；第二子空穴阻挡层142的LUMO能级142L的取值范围可为2.7eV≤|142L|≤3.2eV，优选为2.80eV，其HOMO能级142H的取值范围可为5.9eV≤|142H|≤6.4eV，优选为6.10eV；第一子空穴阻挡层141的LUMO能级141L的取值范围可为2.7eV≤|141L|≤3.2eV，优选为2.70eV，其HOMO能级141H的取值范围可为5.8eV≤|141H|≤6.2eV，优选为6.0eV；发光层13的LUMO能级13L的取值范围可为2.5eV≤|13L|≤3.1eV，优选为2.6eV，其HOMO能级13H的取值范围可为5.7eV≤|13H|≤6.1eV，优选为5.8eV；电子阻挡层151的LUMO能级151L的取值范围可为2.1eV≤|151L|≤2.5eV，优选为2.4eV，其HOMO能级151H的取值范围可为5.6eV≤|151H|≤5.9eV，优选为5.75eV；空穴传输层152的LUMO能级152L的取值范围可为2.4eV≤|152L|≤3.0eV，优选为2.5eV，其HOMO能级152H的取值范围可为5.5eV≤|152H|≤6.0eV，优选为5.7eV；第一电极11的功函数11F的取值范围为|11F|≥4.2eV。此均仅为示例性的说明，而非对本申请实施例提供的有机发光二极管10的限定。
上述每个膜层的能级范围仅为对本申请实施例提供的有机发光二极管10的示例性说明，而非限定。在其他实施方式中，有机发光二极管10的每个膜层的能级范围可根据有机发光二极管10的实际需求设置，本申请实施例对此不作限定。
下面，本申请实施例示例性的示出了一组相关技术提供的OLED与本申请技术方案提供的OLED的发光特性对比表，参见表1。
表1相关技术提供的OLED与本申请技术方案提供的OLED的发光特性对比表
器件 Op.V(V) Eff.1(cd/A) Eff.2(lm/W) CIE(x,y) Peak(nm) BI LT97(h)
D1 3.99 7.41 0.1424 0.0494 460 150 120
D2 4.05 7.40 0.1407 0.0501 460 148 180
其中，器件D1代表相关技术提供的有机发光二极管，器件D2代表本申请技术方案提供的有机发光二极管，器件D1和器件D2的相同之处包括：第一电极的材料采用ITO，厚度为10nm，功函数4.3eV；空穴注入层的厚度为10nm；空穴传输层的厚度为120nm；电子阻挡层的厚度为5nm；发光层的厚度为20nm；电子传输层的厚度为30nm；电子注入层的厚度为1nm，；第二电极的材料采用金属电极，厚度为13～20nm，。器件D1和器件D2的不同之处在于：器件D1的空穴阻挡层为单层结构，厚度为5nm，LUMO能级的位置为2.8eV，HOMO能级的位置为6.1eV；器件D2的空穴阻挡层包括两层子空穴阻挡层，分别为第一子空穴阻挡层和第二子空穴阻挡层，第一子空穴阻挡层位于发光层与第二子空穴阻挡层之间，第一子空穴阻挡层的厚度为3nm，LUMO能级的位置为2.8eV，HOMO能级的位置为6.1eV；第二子空穴阻挡层的厚度为2nm，LUMO能级的位置为2.7eV，HOMO能级的位置为6.0eV。在上述器件D1和器件D2的膜层结构基础上，对两器件的发光特性进行测试，得到如表1所示的测试结果。
其中，Op.V代表工作电压，单位为伏特(V)；Eff.1代表电流效率，单位为坎德拉每安培(cd/A)；Eff.2代表流明效率，单位为流明每瓦(lm/W)；CIE(x,y)代表色坐标；Peak代表峰值位置，单位为纳米(nm)；BI代表蓝光因子，可通过电流效率除以色坐标得到，蓝光因子越大，器件性能越好；LT97代 表器件寿命，单位为小时(h)，代表在1200尼特(nit)下进行恒流测试，得到的器件的寿命值。
由表1中给出的有机发光二极管的发光特性的对比数据可看出，通过将发光二极管结构中的单层空穴阻挡层改变为本申请提出的空穴阻挡层包括至少两层子空穴阻挡层，器件D1与器件D2在工作电压、电流效率、流明效率、色坐标、峰值位置和蓝光因子方面的性能均保持一致；在寿命方面，由器件D1的120h的寿命，提高到器件D2的180h的寿命。因此，本申请技术方案相对于相关技术而言，在保证有机二极管的其他发光特性基本不变的前提下，可将寿命由120h提高到180h，即寿命提升了50％。
上述器件D1与器件D2的对比仅为对本申请实施例提供的有机发光二极管的示例性说明，而非限定。
在上述实施方式的基础上，本申请实施例还提供了一种显示面板。示例性的，图7是本申请实施例提供的一种显示面板的结构示意图。参照图7，该显示面板20包括：衬底基板21，以及位于衬底基板21一侧呈阵列排布的多个像素单元22；其中，像素单元22包括上述实施方式提供的任一种有机发光二极管。本申请实施例提供的显示面板20包括上述任一种有机发光二极管，因此，该显示面板20也具有上述有机发光二极管所具有的有益效果，可参照上文，在此不再赘述。
其中，衬底基板21可为阵列基板，用于驱动像素单元22发光。
示例性的，图7中示出了行方向X和列方向Y(图7中示出的行方向X和列方向Y所在的平面即为衬底基板21所在的平面；图2中示出的由发光层13指向第二电极12的方向Z1和由第二电极12指向发光层13的方向Z2均垂直于上述衬底基板21所在的平面)，且示出了呈7列4行排布的像素单元22，每个像 素单元22可包括一个蓝色子像素221、一个红色子像素222和一个绿色子像素223；同时，多个像素单元22中的子像素均沿列方向Y按照蓝色子像素221、红色子像素222和绿色子像素223的顺序排列，此均仅为对本申请实施例提供的显示面板20的示例性说明，而非限定。在其他实施方式中，可根据显示面板20的实际需求，设置像素单元22的阵列排布方式，以及每个像素单元22中蓝色子像素221、红色子像素222和绿色子像素223的个数以及排布方式，本申请实施例对此不作限定。
另外，本申请实施例对于显示面板20的具体类型不作限定，本申请实施例提出的技术方案可以应用于任意涉及电子和空穴的传输过程的显示面板，示例性的显示面板可以为OLED显示面板、量子点发光二极管(Quantum Dot Light Emitting Diodes，QLED)显示面板或本领域技术人员可知的其他显示面板。

Claims (15)

  1. 一种有机发光二极管，包括：第一电极、第二电极、发光层和空穴阻挡层；
    所述第一电极与所述第二电极相对设置；
    所述发光层位于所述第一电极与所述第二电极之间；
    所述空穴阻挡层位于所述发光层与所述第二电极之间；
    其中，所述空穴阻挡层包括堆叠的至少两层子空穴阻挡层，所述至少两层子空穴阻挡层的LUMO能级依次降低。
  2. 根据权利要求1所述的有机发光二极管，其中，沿所述发光层指向所述第二电极的方向，所述至少两层子空穴阻挡层的LUMO能级依次降低，所述至少两层子空穴阻挡层的HOMO能级依次降低；
    且任意一层所述子空穴阻挡层的LUMO能级低于所述发光层的LUMO能级。
  3. 根据权利要求1所述的有机发光二极管，其中，沿所述第二电极指向所述发光层的方向，所述至少两层子空穴阻挡层的LUMO能级依次降低，所述至少两层子空穴阻挡层的HOMO能级依次降低；
    且任意一层所述子空穴阻挡层的LUMO能级低于所述发光层的LUMO能级。
  4. 根据权利要求1所述的有机发光二极管，其中，相邻两层所述子空穴阻挡层的LUMO能级的能级差L1的取值范围为L1≤0.15eV。
  5. 根据权利要求4所述的有机发光二极管，其中，相邻两层所述子空穴阻挡层的LUMO能级的能级差L1的取值范围为L1≤0.1eV。
  6. 根据权利要求1所述的有机发光二极管，其中，所述发光层的LUMO能级与所述至少两层子空穴阻挡层中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围为L2≤0.1eV；
    其中，所述LUMO能级最高的子空穴阻挡层为LUMO能级与所述发光层的LUMO能级最接近的子空穴阻挡层。
  7. 根据权利要求6所述的有机发光二极管，其中，所述发光层的LUMO能级与所述至少两层子空穴阻挡层中LUMO能级最高的子空穴阻挡层的LUMO能级的能级差L2的取值范围为L2≤0.08eV。
  8. 根据权利要求1所述的有机发光二极管，其中，所述空穴阻挡层中，至少一层所述子空穴阻挡层的HOMO能级与所述发光层的HOMO能级的能级差H1的取值范围为0.2eV≤H1≤0.5eV。
  9. 根据权利要求8所述的有机发光二极管，其中，所述空穴阻挡层中，至少一层所述子空穴阻挡层的HOMO能级与所述发光层的HOMO能级的能级差H1的取值范围为0.3eV≤H1≤0.4eV。
  10. 根据权利要求1所述的有机发光二极管，其中，所述任意一层所述子空穴阻挡层的厚度T1的取值范围为0nm＜T1≤5nm。
  11. 根据权利要求10所述的有机发光二极管，其中，所述任意一层所述子空穴阻挡层的厚度T1的取值范围为0nm＜T1≤3.5nm。
  12. 根据权利要求7所述的有机发光二极管，其中，紧邻所述发光层的所述子空穴阻挡层的厚度T2的取值范围为2nm≤T2≤3nm。
  13. 根据权利要求12所述的有机发光二极管，其中，紧邻所述发光层的所述子空穴阻挡层的厚度T2的取值范围为2.3nm≤T2≤2.8nm。
  14. 根据权利要求1所述的有机发光二极管，其中，还包括第一载流子功能层和第二载流子功能层；
    所述第一载流子功能层位于所述第一电极与所述发光层之间；
    所述第二载流子功能层位于所述空穴阻挡层与所述第二电极之间。
  15. 一种显示面板，包括衬底基板，以及位于所述衬底基板一侧呈阵列排布的多个像素单元；
    其中，所述像素单元包括权利要求1-14任一项所述的有机发光二极管。
PCT/CN2019/071949 2018-09-18 2019-01-16 有机发光二极管和显示面板 WO2020057027A1 (zh)

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