WO2013181897A1 - 有机电致发光器件及其制备方法以及显示装置 - Google Patents

有机电致发光器件及其制备方法以及显示装置 Download PDF

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Publication number
WO2013181897A1
WO2013181897A1 PCT/CN2012/083893 CN2012083893W WO2013181897A1 WO 2013181897 A1 WO2013181897 A1 WO 2013181897A1 CN 2012083893 W CN2012083893 W CN 2012083893W WO 2013181897 A1 WO2013181897 A1 WO 2013181897A1
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layer
sub
matrix material
emitting layer
light
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PCT/CN2012/083893
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English (en)
French (fr)
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杨栋芳
肖田
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京东方科技集团股份有限公司
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Priority to US13/993,187 priority Critical patent/US9166184B2/en
Publication of WO2013181897A1 publication Critical patent/WO2013181897A1/zh

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    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00Organic light-emitting devices
    • H10K50/10OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00Properties of the organic materials covered by group H10K85/00
    • H10K2101/30Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00Properties of the organic materials covered by group H10K85/00
    • H10K2101/40Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00Properties of the organic materials covered by group H10K85/00
    • H10K2101/90Multiple hosts in the emissive layer

Definitions

  • the present invention relates to an organic electroluminescent device, a method of fabricating the same, and a display device. Background technique
  • OLED Organic Light-Emitting Device
  • OLED Organic Electroluminescent Device: Organic Light-Emitting Device
  • the structure of the existing OLED generally includes a substrate 1, an anode layer 2, a cathode layer 10, and an organic functional layer disposed between the anode layer 2 and the cathode layer 10.
  • the organic functional layer includes an empty layer in sequence.
  • the hole injection layer 3 is adjacent to the anode layer 2, and the electron injection layer 9 is adjacent to the cathode layer 10.
  • the luminescence mechanism of the OLED is: when a voltage is applied between the anode layer 2 and the cathode layer 10, the holes injected from the anode layer 2 are driven to enter the luminescence through the hole injection layer 3 and the hole transport layer 4 under the driving of the external voltage.
  • electrons injected from the cathode layer 10 enter the light-emitting layer 6 through the electron injecting layer 9 and the electron transporting layer 8, and holes and electrons entering the light-emitting layer 6 are combined to form excitons in the composite region, and exciton radiation transition Illumination produces a luminescence phenomenon, that is, electroluminescence is formed.
  • the composite region is generally located in the vicinity of the interface with the electron transport layer in the light-emitting layer. After the excitons are formed, they diffuse to both sides of the interface, and a part of the excitons diffuse into the undoped luminescent material region, and then attenuate, so that no radiation transition occurs.
  • An aspect of the invention provides an organic electroluminescent device comprising a substrate, an anode layer, a cathode layer, and an organic functional layer disposed between the anode layer and the cathode layer, the organic functional layer comprising a light-emitting layer, wherein
  • the light-emitting layer includes three sequentially adjacent sub-light-emitting layers, that is, a first sub-light-emitting layer close to the anode layer, a second sub-light-emitting layer, and a third sub-light-emitting layer near the cathode layer.
  • the three sub-emissive layers are made of a host material doped luminescent material; wherein the matrix material of the second sub-emissive layer is mixed with a matrix material, the mixed matrix material is composed of a matrix material having a hole transporting ability and a matrix material having electron transporting ability, wherein the matrix material in the first sub-light emitting layer is a matrix material having a hole transporting ability, and the third sub-light emitting layer is The matrix material is a matrix material having electron transporting ability.
  • the position of the HOMO of the matrix material of the first sub-light-emitting layer is 0.2 ev or more higher than the position of the HOMO of the matrix material of the third sub-light-emitting layer
  • the first sub- The position of the LUMO of the host material of the light-emitting layer is 0.2 ev or more higher than the position of the LUMO of the matrix material of the third sub-light-emitting layer.
  • the matrix material having the hole transporting ability is the same as the matrix material in the first sub-luminescent layer
  • the matrix material having electron transporting ability is the same as the matrix material in the third sub-light emitting layer.
  • the mixing ratio of the matrix material having hole transporting ability to the matrix material having electron transporting ability is in the range of 1:9-9: 1.
  • the host material in the first sub-light emitting layer and the matrix material having hole transporting ability in the second sub-light emitting layer an aromatic diamine compound, a triphenylamine compound An aromatic triamine compound, a biphenyldiamine derivative or a triarylamine polymer; a matrix material in the third sub-light emitting layer; and a matrix material having a electron transporting ability in the second sub-light emitting layer a complex, a carbazole derivative, an imidazole derivative, a phenanthroline derivative or a hydrazine derivative; the first sub luminescent layer, the second sub luminescent layer, and the third sub luminescent layer
  • the luminescent material is made of a phosphorescent material based on Ir, Pt, Ru, Cu.
  • the host material in the first sub-luminescent layer and The matrix material having hole transporting ability in the second sub-light emitting layer is: 9, 10-di-(2-naphthyl) anthracene (ADN), TAZ, CBP, MCP, 4, 4', 4"- Tris(carbazol-9-yl)triphenylamine (TCTA) or ruthenium, ⁇ '-diphenyl-fluorene, ⁇ '-bis(1-naphthyl)-1 ( ⁇ ); in the third sub-luminescent layer a matrix material and a matrix material having electron transporting ability in the second sub-light emitting layer: 8-hydroxyquinoline aluminum (Alq3), 8-hydroxyquinoline lithium (Liq), 1, 3, 5-three ( N-phenyl-2-benzimidazole-2)benzene (TPBI), BCP or Bphen.
  • ADN 9, 10-di-(2-naphthyl) anthracene
  • TAZ Tris(carbazol
  • the thickness of the luminescent layer ranges from 3 to 300 nm
  • the thickness of the first sub luminescent layer, the second sub luminescent layer, and the third sub luminescent layer ranges from 1 -100 ⁇ .
  • the organic functional layer further includes a hole transport layer and an electron transport layer, the hole transport layer being located adjacent to the first sub-light-emitting layer and close to the anode a side, the electron transport layer is located on a side adjacent to the third sub-emissive layer and adjacent to the cathode, wherein an energy level of the hole transport layer matches an energy level of a matrix material of the first sub-emissive layer a hole is introduced into the first sub-light emitting layer; an energy level of the electron transport layer is matched with an energy level of a matrix material of the third sub-light emitting layer, so that electrons enter the third sub-light emitting layer .
  • the position of the HOMO of the hole transporting layer differs from the position of the HOMO of the matrix material of the first sub-luminescent layer by no more than 0.5 ev
  • the position of the LUMO of the electron transporting layer The position of the LUMO of the matrix material of the third luminescent layer differs by no more than 0.5 ev.
  • the hole transport layer includes two or more sub-hole transport layers, and the sub-hole transport layer includes at least a first hole transport layer and a second hole a transport layer, the second hole transport layer is adjacent to the first sub-emissive layer, and a position of a HOMO of the second hole transport layer is different from a position of a HOMO of the matrix material of the first sub-emissive layer Not more than 0.2 ev; the position of the LUMO of the electron transport layer differs from the position of the LUMO of the matrix material of the third sub-light-emitting layer by no more than 0.2 ev.
  • Another aspect of the present invention provides a display device comprising the above electroluminescent device. Still another aspect of the present invention provides a method of fabricating an organic electroluminescent device, comprising the steps of: forming a light-emitting layer, wherein the step of fabricating the light-emitting layer comprises:
  • first sub-emissive layer made of a matrix material doped luminescent material having a hole transporting ability
  • second sub-emissive layer on the first sub-emissive layer, the second sub-emissive layer being made of a matrix material having a hole transporting ability and a matrix material having electron transporting ability and doped with a luminescent material;
  • FIG. 1 is a schematic structural view of an organic electroluminescent device in the prior art
  • FIG. 2 is a schematic structural view of an organic electroluminescent device according to Embodiment 1 of the present invention.
  • FIG. 3 is a schematic structural view of an organic electroluminescent device according to Embodiments 2 and 3 of the present invention
  • FIG. 4 is a current density-current efficiency curve of the organic electroluminescent device according to Embodiment 2 of the present invention
  • Fig. 5 is a graph showing the luminance-current efficiency of the organic electroluminescent device of Example 3 of the present invention.
  • 6 is a schematic diagram showing the energy level structure of Embodiment 2;
  • Embodiment 7 is a schematic diagram showing the energy level structure of Embodiment 3.
  • Figure 8 is a flow chart showing a method of preparing an organic electroluminescent device of the present invention.
  • the vacuum or infinity is defined as the energy zero, and all the carriers are in a negative energy level.
  • the energy level value refers to the value after taking the absolute value thereof, that is, the value of the energy level is described by the magnitude of the absolute value, for example, the energy level value at the vacuum or infinity is 0, and the low work function.
  • the energy level of the value refers to the energy level with the absolute value (level value) of the energy level.
  • the energy level of the high power function value refers to the energy level with the absolute value of the energy level (energy level value);
  • the level of the energy level is compared, for example: the position of the energy level of the low work function value is higher than the position of the energy level of the high work function value, or the position of the energy level of the 5 ev level value. It is lower than the energy level of the 3ev energy level.
  • the organic electroluminescent device comprises a substrate 1, an anode layer 2, a cathode layer 10, and an organic functional layer disposed between the anode layer 2 and the cathode layer 10.
  • the organic functional layer includes a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, a hole and exciton blocking layer 7, an electron transport layer 8, and an electron injecting layer 9.
  • An external power source 11 is connected between the anode layer 2 and the cathode layer 10, and the organic electroluminescent device emits light under the driving of the external power source 11.
  • the organic electroluminescent device of the present embodiment includes a substrate 1, an anode layer 2, a cathode layer 10, and an organic functional layer disposed between the anode layer 2 and the cathode layer 10, the organic functional layer Only the hole transport layer 4, the light-emitting layer 6, and the electron transport layer 8 may be included.
  • the organic electroluminescent device of the present embodiment includes a substrate 1, an anode layer 2, a cathode layer 10, and an organic functional layer disposed between the anode layer 2 and the cathode layer 10, the organic functional layer Can also only A light emitting layer 6 is included.
  • the light-emitting layer 6 includes three adjacent light-emitting layers, that is, a first sub-light-emitting layer 61 close to the anode layer 2, a third sub-light-emitting layer 63 near the cathode layer 10, and A second sub-emissive layer 62 between the sub-emissive layer 61 and the third sub-emissive layer 63.
  • the three sub-emissive layers are each made of a matrix material doped luminescent material, wherein the matrix material of the second sub-emissive layer 62 is mixed with a matrix material composed of a matrix material having hole transporting ability and having electrons
  • the matrix material of the transport capability is mixed
  • the matrix material in the first sub-light-emitting layer 61 is a single-substrate material having a hole transporting ability
  • the matrix material in the third sub-light-emitting layer 63 is a single substrate having electron transporting ability. material.
  • the matrix material having a hole transporting ability means a matrix material having a hole transporting ability stronger than the electron transporting ability
  • the matrix material having electron transporting ability means a matrix material having an electron transporting ability stronger than a hole transporting ability.
  • having a hole transporting ability can be defined as a charge transporting ability when a mobility of holes is larger than a mobility of electrons, and can be measured by a conventional method such as a time-of-flight method; a matrix material having electron transporting ability or having a hole Transmission capacity can be similarly pushed.
  • HOMO Highest Occupied Molecular
  • the position of the Orbital, the highest occupied orbital is 0.2 ev or more higher than the position of the HOMO of the matrix material of the third sub-light-emitting layer 63, and the LUMO of the matrix material of the first sub-light-emitting layer 61 ( Lowest Unoccupied Molecular Orbital)
  • the position of the substrate is 0.2 ev or more higher than the position of the LUMO of the matrix material of the third sub-light-emitting layer 63.
  • the matrix material in the first sub-light-emitting layer 61 may be an aromatic diamine compound, a triphenylamine compound, an aromatic triamine compound, a biphenylenediamine derivative or a triarylamine polymer.
  • the matrix material in the first sub-light-emitting layer 61 is: 9, 10-di-(2-naphthyl) anthracene (ADN), TAZ, CBP, MCP, 4, 4', 4"-three (carbazol-9-yl)triphenylamine (TCTA) or hydrazine, ⁇ '-diphenyl-hydrazine, ⁇ '-bis(1-naphthyl)-1 ( ⁇ ).
  • the matrix material in the third sub-light-emitting layer 63 may be a metal complex, a carbazole derivative, an imidazole derivative, a phenanthroline derivative or a derivative of hydrazine.
  • the matrix material in the third sub-light-emitting layer 63 is: 8-hydroxyquinoline aluminum (Alq3), 8-hydroxyquinolate lithium (Liq), 1, 3, 5-tris(N-phenyl -2- benzoamidazole-2) benzene (TPBI), BCP or Bphen.
  • the matrix material having the hole transporting ability in the mixed matrix material of the second sub-light-emitting layer 62, is the same as the matrix material in the first sub-light-emitting layer 61, and has an electron.
  • the substrate material for the transfer ability is the same as the matrix material of the third sub-light-emitting layer 63.
  • the mixing ratio of the matrix material having a hole transporting ability to the matrix material having electron transporting ability may range from 1:9 to 9:1, and in the present embodiment, the ratio is 1:1.
  • the luminescent material in the first sub luminescent layer 61, the second sub luminescent layer 62, and the third sub luminescent layer 63 may be a phosphorescent material based on Ir, Pt, Ru, or Cu.
  • the phosphorescent material can be used with FIrpic, Fir6, Fir, FIrtaz, Ir(ppy) 3 , IrPi, Ir(ppy) 2 (acac), PtOEP, (btp) 2 Iracac, Ir(piq) 2 ( Acac), (MDQ) 2 Iracac et al.
  • the thickness of the luminescent layer may range from 3 to 300 nm, and the thickness of the first sub luminescent layer 61, the second sub luminescent layer 62, and the third sub luminescent layer 63 may range from 1 to 100 nm. In this embodiment, the thicknesses of the first sub-light emitting layer 61, the second sub-light emitting layer 62, and the third sub-light emitting layer 63 may each be 10 nm.
  • the energy level of the hole transport layer 4 matches the energy level of the matrix material of the first sub-light emitting layer 61, that is, the position of the HOMO of the hole transport layer 4 and the position of the HOMO of the matrix material of the first sub-light emitting layer 61.
  • the position of the HOMO of the hole transport layer 4 is 0.5 ev or less higher than the position of the HOMO of the matrix material of the first sub-light-emitting layer 61, so that holes can smoothly enter the first sub-light-emitting layer 61;
  • the energy level of the layer 8 is matched with the energy level of the matrix material of the third sub-light-emitting layer 63, that is, the position of the LUMO of the electron transport layer 8 is close to the position of the LUMO of the matrix material of the third sub-light-emitting layer 63, and the electron transport layer
  • the position of LUMO of 8 is lower than the position of LUMO of the matrix material of the third sub-light-emitting layer 63 by 0.5 ev or less, so that electrons can smoothly enter the third sub-light-emitting layer 63.
  • the injection barrier of hole carriers and electron carriers is reduced, which is advantageous for increasing the efficiency of injecting electron carriers and hole carriers into the light-emitting layer, thereby improving organic electricity.
  • the luminous efficiency of the light-emitting device due to the above-mentioned energy level matching relationship, the injection barrier of hole carriers and electron carriers is reduced, which is advantageous for increasing the efficiency of injecting electron carriers and hole carriers into the light-emitting layer, thereby improving organic electricity.
  • the position of the HOMO of one hole transport layer immediately adjacent to the light-emitting layer is different from the position of the HOMO of the matrix material of the first sub-light-emitting layer 61 (the former is higher than the latter) does not exceed 0.2 ev; or, when the electron transport layer includes two or more sub-electron transport layers, the position of the LUMO of one electron transport layer 8 adjacent to the light-emitting layer and the third sub-light-emitting layer
  • the LUMO of the matrix material of 63 differs in position (the former is lower than the latter) and does not exceed 0.2 ev.
  • the position of the HOMO of the hole transport layer immediately adjacent to the light-emitting layer is 0.2 ev or less higher than the position of the HOMO of the host material of the first sub-light-emitting layer 61, and the position of the LUMO of the electron transport layer 8 adjacent to the light-emitting layer is higher than that of the third sub-
  • the LUMO bit of the matrix material of the light-emitting layer 63 Lower 0.2ev and below.
  • the hole transport layer 4 or a hole transport layer adjacent to the light-emitting layer is made of the same material as the matrix material of the first sub-light-emitting layer 61, or the electron transport layer 8 or one of the adjacent light-emitting layers
  • the electron transport layer is made of the same material as the matrix material of the third sub-light-emitting layer 63.
  • the hole and exciton blocking layer 7 and the electron transporting layer 8 may be made of the same material, and the HOMO of the material is lower than the HOMO of the matrix material having the hole transporting ability in the light emitting layer. s position.
  • the hole and exciton blocking layer 7 and the electron transporting layer 8 may be substituted with a phenanthroline derivative, an oxazole derivative, a thiazole derivative, an imidazole derivative, a metal complex, and a derivative of hydrazine.
  • Alq3 8-hydroxyquinoline aluminum
  • Liq 8-hydroxyquinolate lithium
  • 8-hydroxyquinoline gallium bis[2-(2-hydroxyphenyl-1)-pyridine] fluorene, 2-(4-diphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), 1, 3, 5-tris(N-phenyl-2-phenyl And imidazole-2) benzene (TPBI), BCP, Bphen,
  • the holes and the exciton blocking layer 7 and the electron transporting layer 8 may be provided in the same layer, which simultaneously functions as hole blocking, exciton blocking, and electron transport.
  • the hole transport layer 4 can be made of an aromatic diamine compound, a triphenylamine compound, an aromatic triamine compound, a biphenyldiamine derivative, a triarylamine polymer, and a carbazole polymer. to make.
  • aromatic diamine compound a triphenylamine compound
  • aromatic triamine compound a biphenyldiamine derivative
  • a triarylamine polymer a carbazole polymer.
  • carbazole polymer such as NPB, TPD, TCTA, and polyvinylcarbazole or their monomers.
  • the material of the electron blocking layer 5 can be selected in a range that is compatible with the material selection of the hole transport layer 4.
  • the hole injection layer 3 may be made of a triphenylamine compound or a P-type doped organic layer or a polymer such as tris-[4-(5-phenyl-2-thienyl)benzene]amine, 4 ,4,4,,-Tris[2-naphthyl(phenyl)tt]triphenylamine (2-TNATA) or 4,4,,4,,-tris-(3-nonylphenylanilino)triphenylamine ( m- MTDATA ), beryllium copper (CuPc), Pedot: Pss, TPD or F4TCNQ.
  • a triphenylamine compound or a P-type doped organic layer or a polymer such as tris-[4-(5-phenyl-2-thienyl)benzene]amine, 4 ,4,4,,-Tris[2-naphthyl(phenyl)tt]triphenylamine (2-TNATA) or 4,4,,4,
  • the substrate 1 serves as an electrode layer and an organic functional layer, has good light transmission properties in the visible light region, has a certain ability to penetrate water vapor and oxygen, has good surface flatness, and may be glass or A flexible substrate or a TFT back sheet, wherein the flexible substrate can be made of one of a polyester type, a polyimide, or a thin metal.
  • the anode layer 2 serves as a connection layer for the forward voltage of the organic electroluminescent device, and has good electrical conductivity, visible light transparency, and a high work function value.
  • the anode layer 2 is usually made of an inorganic metal oxide (for example, indium tin oxide ITO, oxidized rhodium, etc.) or an organic conductive polymer (such as PEDOT: PSS, PANI, etc.) or metal materials with high work function values (such as: gold, copper, silver, platinum, etc.).
  • the cathode layer 10 serves as a connection layer for the negative voltage of the organic electroluminescent device, and has good electrical conductivity and a low work function value.
  • the cathode layer 10 is usually made of a metal material having a low work function value, such as lithium, magnesium, calcium, barium, aluminum, indium, or the like, or a metal material having a low work function value and an alloy of copper, gold, and silver.
  • a metal material having a low work function value such as lithium, magnesium, calcium, barium, aluminum, indium, or the like, or a metal material having a low work function value and an alloy of copper, gold, and silver.
  • the HOMO of the mixed matrix material is positioned to be the first one.
  • the position of the HOMO of the host material of the light-emitting layer 61 is low, so that a part of hole carriers can be collected at the interface of the first sub-light-emitting layer 61 and the second sub-light-emitting layer 62; at the same time, the matrix of the first sub-light-emitting layer 61
  • the position of the LUMO of the material is higher than the position of the LUMO of the mixed matrix material of the second sub-light-emitting layer 62, so that a part of the electron carriers can be collected at the above-mentioned interface, so the first sub-light-emitting layer 61 and the second sub-light-emitting layer
  • the interface at 62 can form a carrier recombination zone.
  • a carrier recombination zone can also be formed at the interface of the second sub-light-emitting layer 62 and the third sub-light-emitting layer 63.
  • the matrix material since the matrix material is used, it has a matrix material mixed with two different carrier transporting capabilities, for example, a matrix material having 50% of hole transporting ability and 50% of electrons.
  • the carrier material of the transport capability so that the second sub-emissive layer 62 can simultaneously transport two kinds of carriers, and the recombination area of the carriers is wide, so that the light-emitting layer 6 forms a wide carrier recombination zone.
  • the concentration of carriers and excitons is reduced, and on the other hand, the range of carrier recombination is increased, thereby improving the efficiency of the organic electroluminescent device and reducing the efficiency at high current density.
  • the method of preparing the organic electroluminescent device comprises the following steps.
  • the substrate 1 was sequentially washed in a cleaning agent, an ethanol solution, an acetone solution, and deionized water, followed by drying with dry nitrogen.
  • the substrate 1 is placed in a vacuum evaporation chamber for the preparation of the anode layer 2 or the cathode layer 10 or other treatment.
  • the substrate 1 is transferred into a vacuum evaporation chamber, and an indium tin oxide (ITO) film is formed on the substrate 1, whereby the anode layer 2 of the organic electroluminescent device is formed on the substrate 1. among them,
  • ITO indium tin oxide
  • the sheet resistance of the ITO film was 25 ⁇ / ⁇ .
  • step S1) and the step S2) may be completed in advance to form a corresponding substrate with an anode layer or a cathode layer to facilitate direct utilization in the subsequent processing.
  • the substrate 1 on which the anode layer 2 is prepared is moved into a vacuum chamber, and the anode layer 2 is pretreated with oxygen plasma or pretreated with argon plasma to improve the cleanliness and surface smoothness of the ITO film. Degree, improve the surface properties of ITO film and increase its work function value.
  • an organic functional layer is prepared on the treated anode layer 2 or cathode layer 10, wherein the light-emitting layer 6 includes three sub-light-emitting layers.
  • the treated substrate 1 is transferred into a vacuum chamber, and then an organic functional layer is prepared.
  • the evaporation order is as follows: hole injection layer 3, hole transport layer 4, electron blocking layer 5, light-emitting layer 6, hole and exciton blocking layer 7, electron The transport layer 8 and the electron injection layer 9.
  • the light emitting layer 6 is a first sub-light emitting layer 61, a second sub-light emitting layer 62, and a third sub-light emitting layer 63 in order from bottom to top.
  • the manufacturing process of the luminescent layer 6 includes:
  • first sub-emissive layer 61 1) fabricating a first sub-emissive layer 61, the first sub-emissive layer being made of a base material doped luminescent material having a hole transporting ability;
  • the third sub-emissive layer 63 is formed on the second sub-emissive layer, the third sub-emissive layer being made of a host material doped luminescent material having electron transporting ability.
  • the substrate 1 is placed under high vacuum conditions to prepare the cathode layer 10.
  • the vapor deposition rate and thickness of each of the organic functional layers constituting the organic electroluminescent device involved in the above step S2) - step S5) are monitored by a film thickness meter disposed in the vicinity of the substrate.
  • the prepared organic electroluminescent device is transferred to a hand-operated box for packaging, and the hand-operated box is inert
  • the body atmosphere in this embodiment, is a nitrogen atmosphere.
  • a display device comprising the above electroluminescent device.
  • the organic electroluminescent device of the present embodiment comprises a substrate 1, an anode layer 2, a cathode layer 10, and an organic functional layer disposed between the anode layer 2 and the cathode layer 10.
  • the organic functional layer includes the light-emitting layer 6.
  • the structure of the light-emitting layer 6 is the same as that of the light-emitting layer 6 in the first embodiment, that is, the light-emitting layer includes three sub-light-emitting layers (composite regions), that is, the first sub-light-emitting layer 61, The two sub-light emitting layers 62 and the third sub-light emitting layer 63.
  • the matrix material of the second sub-light-emitting layer 62 is mixed with a matrix material composed of a matrix material having a hole transporting ability and a matrix material having electron transporting ability; the first sub-light emitting layer 61
  • the matrix material is made of a matrix material having a hole transporting ability; and the matrix material in the third sub-light emitting layer 63 is made of a matrix material having electron transporting ability.
  • the hole transport layer 4 in the organic functional layer includes two sub-hole transport layers, that is, the hole transport layer includes a first hole transport layer 41 and a second void.
  • the hole transport layer 42 and the second hole transport layer 42 are adjacent to the light-emitting layer 6.
  • the first hole transport layer 41 is adjacent to the hole injection layer 3
  • the second hole transport layer 42 is adjacent to the first sub-light-emitting layer 61.
  • the hole injecting layer 3 may not be included in the organic functional layer of the organic electroluminescent device of the present embodiment on the basis of that shown in Fig. 3.
  • the organic functional layer of the organic electroluminescent device of the present embodiment may not have the electron blocking layer 5 on the basis of that shown in Fig. 3.
  • the electron blocking layer 5 may be provided in practical applications, and the material selection of the electron blocking layer 5 may be the same as that of the hole transport layer 4 in the first embodiment.
  • the above-mentioned organic functional layer may include only the hole transport layer 4, the light-emitting layer 6, and the electron transport layer 8.
  • the hole transport layer includes a first hole transport layer 41 and a second hole transport layer 42.
  • the material of the first hole transport layer 41 is made of the same material as that of the hole transport layer 4 of Embodiment 1; meanwhile, the position of the HOMO (highest occupied track) of the second hole transport layer 42 and the first sub-light-emitting layer 61
  • the position of the HOMO is better matched.
  • the positions of the energy levels of the two are different by less than 0.2 ev, that is, the position of the HOMO of the second hole transport layer 42 and the first sub-light emitting layer.
  • the position of the HOMO of the matrix material of 61 differs by no more than 0.2 ev; and the position of the LUMO (lowest unoccupied orbit) of the matrix material having the hole transporting ability in the second hole transporting layer 42 and the first sub-light emitting layer 61 is higher.
  • the position of the LUMO of the host material having the electron transporting ability in the second light emitting layer 62 That is, the position of the HOMO of the second hole transport layer 42 is 0.2 ev or less higher than the position of the HOMO of the matrix material of the first sub-light-emitting layer 61.
  • the second hole transport layer 42 is made of the same material as the matrix material of the first sub-light-emitting layer 61, that is, a material having a hole transporting ability.
  • the position of the LUMO of the electron transport layer 8 adjacent to the light-emitting layer is 0.2 ev or less lower than the position of the LUMO of the matrix material of the third sub-light-emitting layer 63.
  • the hole and exciton blocking layer 7 adjacent to the third sub-light emitting layer 63 and the electron transporting layer 8 are made of the same material as the matrix material of the third sub-light emitting layer 63, that is, the electron transporting ability is used. material.
  • the hole transport layer 4 in the embodiment of the present invention may include two or more sub-hole transport layers, the sub-hole transport layer includes at least a first hole transport layer 41, and a second a hole transport layer 42 (not shown), the first hole transport layer 41 is adjacent to the hole injection layer, and the second hole transport layer 42 is adjacent to the first sub-light emitting layer .
  • the position of the HOMO of the second hole transport layer 42 is 0.2 ev or less higher than the position of the HOMO of the host material of the first sub-light emitting layer 61.
  • the structures of the other layers of the organic electroluminescent device are the same as those of the embodiment 1, and are not described herein again.
  • the specific composition of each layer in the organic electroluminescent device is as follows, and the preparation materials and thicknesses of the specific layers are as follows: Glass/ITO/2-TNATA (10 nm) / NPB (20 nm) / TCTA (10 nm) I TCTA: Ir(ppy) 3 (10 nm) / TCTA: TPBI: Ir(ppy) 3 (10 nm) / TPBI: Ir(ppy) 3 (10 nm) / TPBI ( 40 nm ) / LiF (0.5 ⁇ ) / Al (200 ⁇ ).
  • the luminescent layer 62 is TCTA: TPBI: Ir(ppy) 3 It is made to have a thickness of 10 nm; the third sub-light-emitting layer 63 is made of TPBI: Ir(ppy) 3 and has a thickness of 10 nm; the hole and exciton blocking layer 7 also serves as an electron transport layer 8 and is made of TPBI.
  • the thickness of the electron injecting layer 9 is made of LiF and has a thickness of 0.5 nm; the cathode layer 10 is made of A1 and has a thickness of 200 nm.
  • the luminescent materials (ie, dopants) in the three sub-luminescent layers in the composite luminescent layer are all doped with the green phosphorescent dopant Ir(ppy) 3 .
  • the substrate 1 was ultrasonically washed successively with a cleaning agent, an acetone solution, and deionized water, and washed and dried with dry nitrogen.
  • the substrate 1 on which the anode layer 2 has been formed is subjected to ultraviolet light treatment for 25 minutes to improve the cleanliness and surface flatness of the surface of the ITO film, improve the surface characteristics of the ITO film, and improve the work function value.
  • the vapor deposition sequence is as follows: Hole injection layer 3: ⁇ is made of a 2-TNATA material having a thickness of 10 nm and an evaporation rate of 0.08 nm/s; the first hole transport layer 41: ⁇ Made of NPB material, the thickness is 20 nm, the evaporation rate is 0.08 nm / s; The second hole transport layer 42: ⁇ is made of TCTA material, the thickness is 10 nm, the evaporation rate is 0.08 nm / s; In the light-emitting layer 6: the first sub-light-emitting layer 61: the host material is made of TCTA material, wherein the doped luminescent material Ir(ppy) 3 has a thickness of 10 nm and an evaporation rate of 0.08 nm/s; the second sub-luminescent layer 62: The mixed matrix material is a mixed material of TCTA and TPBI, wherein the doped luminescent material Ir(ppy) 3 is a
  • the cathode layer 10 was formed by vapor deposition under a high vacuum condition of a vacuum of 5 ⁇ 10 4 .
  • the cathode layer 10 is made of metal A1, and its thickness is 200 nm, and the evaporation rate is
  • Fig. 4 is a graph showing the current density-current efficiency of the organic electroluminescent device of the present embodiment.
  • the organic electroluminescent device of the prior art for example: specific structure: Glass/ITO/2-TNATA (10 ⁇ ) / NPB (20 ⁇ ) / TCTA (10 nm) / TCTA: Ir(ppy) 3 ( 15 nm) / TPBI: Ir(ppy) 3 (15 nm) / TPBI (40 nm ) / LiF (0.5 nm ) / Al (200 nm )
  • the three sub-light-emitting layers have a wider composite region in the light-emitting layer, which can effectively reduce exciton quenching and improve the luminous efficiency of the organic electroluminescent device.
  • the current efficiency of organic electroluminescent devices is significantly higher than that of prior art organic electroluminescent devices.
  • FIG. 6 is a schematic diagram showing the energy level structure of the organic electroluminescent device of the present embodiment.
  • the interface between the first sub-emissive layer 61 and the second sub-emissive layer 62 and the interface between the second sub-emissive layer 62 and the third sub-emissive layer 63 are significantly loaded.
  • the carrier barrier, a portion of the carriers are blocked at the two interfaces to form a carrier recombination zone.
  • the excitons Since the exciton diffusion length is generally less than 10 nm, the excitons generally do not diffuse into the region of the undoped dopant (luminescent material), that is, the main recombination region of the excitons is substantially located inside the luminescent layer, thereby reducing the non-radiative transition.
  • the number of excitons avoids the influence of no radiation attenuation on the lifetime of the organic electroluminescent device, and also improves the luminous efficiency of the organic electroluminescent device.
  • the injection barrier of the hole ensures that the hole can be efficiently injected into the light-emitting layer; at the same time, the hole and the exciton blocking layer/electron transport layer are respectively made of the same material as the matrix material in the third sub-light-emitting layer 63, thereby ensuring The electrons can be efficiently injected into the light-emitting layer 6, which greatly improves the light-emitting efficiency of the organic electroluminescent device.
  • the organic electroluminescent device of this embodiment has the same structure as that of the organic electroluminescent device of Embodiment 2, which differs from Embodiment 2 in that the luminescent materials used in the luminescent layer are different.
  • the luminescent material in the luminescent layer is coated with a daunting dopant IrPi, which has a short triplet lifetime (less than 500 nanoseconds), and the dopant content of each of the three sub-luminescent layers is 6%.
  • the constituent materials of the organic electroluminescent device in this embodiment are as follows: Glass/ITO/2-TNATA (10 ⁇ ) / NPB (20 ⁇ ) / TCTA (10 ⁇ ) I TCTA: IrPi(10 ⁇ ) I TCTA: TPBI: IrPi (10 ⁇ ) / TPBI (40 ⁇ ) / LiF (0.5 ⁇ ) / Al (200 nm).
  • the three sub-light-emitting layers in the light-emitting layer of the present embodiment are: the first sub-light-emitting layer 61 is made of TCTA:IrPi and has a thickness of 10 nm; and the second sub-light-emitting layer 62 is made of TCTA:TPBI:IrPi, The thickness is 10 nm; the third sub-light-emitting layer 63 is made of TPBI: IrPi and has a thickness of 10 nm.
  • the luminescent material (dopant) is made of IrPi (green phosphorescent dopant).
  • Fig. 7 is a view showing the energy levels of the structure of the organic electroluminescent device of Example 3.
  • the organic electroluminescent device has a wide recombination zone which reduces the concentration of carriers and excitons, reduces exciton quenching, and increases hole current carrying. Sub-electron carrier Probability.
  • the organic electroluminescent device of Embodiments 1-3 is not only applicable to Embodiment 1 by providing a matrix material having different carrier transporting ability in the light-emitting layer to form a plurality of sub-light-emitting layers.
  • the bottom emission type organic electroluminescence device described in 3 is also applicable to a top emission type organic electroluminescence device.
  • the efficiency of injecting electron carriers and hole carriers into the light-emitting layer increases the probability of recombination of electron carriers and hole carriers, improves the utilization efficiency of carriers, and finally improves the organic electroluminescent device.
  • the luminous efficiency ensures that the organic electroluminescent device still has high current efficiency under high brightness, and the performance of the organic electroluminescent device is improved.

Abstract

一种有机电致发光器件及其制备方法以及显示装置。有机电致发光器件包括衬底(1)、阳极层(2)、阴极层(10)以及有机功能层,有机功能层包括发光层(6),发光层(6)包括三个依次相邻的子发光层,即靠近阳极层的第一子发光层(61)、第二子发光层(62)和靠近阴极层的第三子发光层(63)。有机电致发光器件能够有效提高载流子的利用效率,从而提高有机电致发光器件的发光效率。

Description

有机电致发光器件及其制备方法以及显示装置 技术领域
本发明涉及一种有机电致发光器件及其制备方法以及显示装置。 背景技术
OLED (有机电致发光器件: Organic Light-Emitting Device )是一种利用 有机固态半导体作为发光材料的发光器件, 由于其具有制备工艺简单、 成本 低、 功耗低、 发光亮度高、 工作温度适应范围广等优点, 使其具有广阔的应 用前景。
如图 1所示, 现有的 OLED的结构通常包括衬底 1、 阳极层 2、 阴极层 10以及设置在阳极层 2和阴极层 10之间的有机功能层, 所述有机功能层依 次包括空穴注入层 3、 空穴传输层 4、 电子阻挡层 5、 发光层 6、 空穴与激子 阻挡层 7、电子传输层 8、 以及电子注入层 9。 空穴注入层 3与阳极层 2相邻, 电子注入层 9与阴极层 10相邻。
OLED的发光机理为: 当阳极层 2和阴极层 10之间施加有电压时,在外 界电压的驱动下, 由阳极层 2注入的空穴通过空穴注入层 3和空穴传输层 4 进入发光层 6中, 由阴极层 10注入的电子通过电子注入层 9和电子传输层 8 进入发光层 6中, 进入到发光层 6中的空穴和电子在复合区复合形成激子, 激子辐射跃迁发光而产生发光现象, 即形成电致发光。
由于空穴和电子具有不同的迁移率, 复合区一般位于发光层中, 与电子 传输层的交界面附近。 激子形成后, 向该交界面的两侧扩散, 一部分激子会 扩散到未掺杂发光材料的区域, 然后衰减, 从而发生无辐射跃迁。
为了充分利用电子载流子和空穴载流子复合释放的能量,提高 OLED中 载流子利用效率, 从而提高有机电致发光器件的发光效率, 是目前有机光电 技术领域亟待解决的问题。 发明内容 种有机电致发光器件以及制备方法以及显示装置, 该有机电致发光器件能够 有效提高载流子的利用效率, 从而提高有机电致发光器件的发光效率。
本发明的一个方面提供了一种有机电致发光器件, 包括衬底、 阳极层、 阴极层以及设置在阳极层和阴极层之间的有机功能层, 所述有机功能层包括 发光层, 其中, 所述发光层包括三个依次相邻的子发光层, 即靠近阳极层的 第一子发光层、 第二子发光层和靠近阴极层的第三子发光层。
对于该有机电致发光器件, 例如, 所述三个子发光层均釆用基质材料掺 杂发光材料制成; 其中所述第二子发光层的基质材料釆用混合基质材料, 该 混合基质材料由具有空穴传输能力的基质材料和具有电子传输能力的基质材 料混合而成, 所述第一子发光层中的基质材料釆用具有空穴传输能力的基质 材料, 所述第三子发光层中的基质材料釆用具有电子传输能力的基质材料。
对于该有机电致发光器件, 例如, 所述第一子发光层的基质材料的 HOMO的位置比所述第三子发光层的基质材料的 HOMO的位置高 0.2ev或 以上,所述第一子发光层的基质材料的 LUMO的位置比所述第三子发光层的 基质材料的 LUMO的位置高 0.2ev或以上。
对于该有机电致发光器件,例如,所述第二子发光层的混合基质材料中, 具有空穴传输能力的基质材料釆用与所述第一子发光层中的基质材料相同的 基质材料, 具有电子传输能力的基质材料釆用与所述第三子发光层中的基质 材料相同的基质材料。
对于该有机电致发光器件,例如,所述第二子发光层的混合基质材料中, 具有空穴传输能力的基质材料与具有电子传输能力的基质材料的混合比例范 围为 1:9-9:1。
对于该有机电致发光器件, 例如, 所述第一子发光层中的基质材料以及 所述第二子发光层中具有空穴传输能力的基质材料釆用芳香族二胺类化合 物、三苯胺化合物、 芳香族三胺类化合物、联苯二胺衍生物或三芳胺聚合物; 所述第三子发光层中的基质材料以及所述第二子发光层中具有电子传输能力 的基质材料釆用金属配合物、 咔唑类衍生物、 咪唑类衍生物、 邻菲罗林衍生 物或蒽的衍生物; 所述第一子发光层、 所述第二子发光层和所述第三子发光 层中的发光材料釆用基于 Ir、 Pt、 Ru、 Cu的磷光材料。
对于该有机电致发光器件, 例如, 所述第一子发光层中的基质材料以及 所述第二子发光层中具有空穴传输能力的基质材料釆用: 9, 10-二 - ( 2-萘基) 蒽 (ADN ) 、 TAZ、 CBP、 MCP、 4,4',4"-三 (咔唑 -9-基)三苯胺(TCTA )或 Ν,Ν'-二苯基 -Ν,Ν'-二 (1-萘基) -1 ( ΝΡΒ ) ; 所述第三子发光层中的基质材料以 及所述第二子发光层中具有电子传输能力的基质材料釆用: 8-羟基喹啉铝 ( Alq3 )、 8-羟基喹啉锂(Liq )、 1 , 3 , 5-三( N-苯基 -2-笨并咪唑 -2 )苯( TPBI )、 BCP或 Bphen。
对于该有机电致发光器件, 例如, 所述发光层的厚度范围为 3-300nm, 所述第一子发光层、 所述第二子发光层以及所述第三子发光层的厚度范围为 1-100匪。
对于该有机电致发光器件, 例如, 所述有机功能层中还包括有空穴传输 层和电子传输层, 所述空穴传输层位于与所述第一子发光层相邻且靠近阳极 的一侧, 所述电子传输层位于与所述第三子发光层相邻且靠近阴极的一侧, 其中, 空穴传输层的能级与所述第一子发光层的基质材料的能级相匹配, 以 便于空穴进入所述第一子发光层; 所述电子传输层的能级与所述第三子发光 层的基质材料的能级相匹配, 以便于电子进入所述第三子发光层。
对于该有机电致发光器件, 例如, 所述空穴传输层的 HOMO 的位置与 所述第一子发光层的基质材料的 HOMO的位置相差不超过 0.5ev, 所述电子 传输层的 LUMO的位置与所述第三发光层的基质材料的 LUMO的位置相差 不超过 0.5ev。
对于该有机电致发光器件, 例如, 所述空穴传输层包括两个或两个以上 的子空穴传输层, 所述子空穴传输层至少包括第一空穴传输层和第二空穴传 输层, 所述第二空穴传输层与所述第一子发光层相邻, 所述第二空穴传输层 的 HOMO的位置与所述第一子发光层的基质材料的 HOMO的位置相差不超 过 0.2ev; 所述电子传输层的 LUMO的位置与所述第三子发光层的基质材料 的 LUMO的位置相差不超过 0.2ev。
本发明的另一个方面提供了一种显示装置,其包括上述的电致发光器件。 本发明的再一个方面提供了一种有机电致发光器件的制备方法, 包括制 作发光层的步骤, 所述发光层的制作步骤包括:
1 )制作第一子发光层,所述第一子发光层由具有空穴传输能力的基质材 料掺杂发光材料制成; 2 )在第一子发光层上制作第二子发光层,所述第二子发光层由具有空穴 传输能力的基质材料和具有电子传输能力的基质材料混合并掺杂发光材料制 成;
3 )在第二子发光层上制作第三子发光层,所述第三子发光层由具有电子 传输能力的基质材料掺杂发光材料制成。 附图说明
为了更清楚地说明本发明实施例的技术方案, 下面将对实施例的附图作 简单地介绍,显而易见地,下面描述中的附图仅仅涉及本发明的一些实施例, 而非对本发明的限制。
图 1为现有技术中有机电致发光器件的结构示意图;
图 2为本发明实施例 1中有机电致发光器件的结构示意图;
图 3为本发明实施例 2、 3中有机电致发光器件的结构示意图; 图 4为本发明实施例 2所示有机电致发光器件的电流密度 -电流效率曲 线;
图 5为本发明实施例 3所示有机电致发光器件的亮度-电流效率曲线。 图 6为实施例 2的能级结构示意图;
图 7为实施例 3的能级结构示意图;
图 8为本发明有机电致发光器件的制备方法的流程图。
附图标记
1 - 底, 2 -阳极层, 3 -空穴注入层,
4 _空穴传输层, 5 _电子阻挡层, 6 -发光层,
7 -空穴与激子阻挡层, 8 -电子传输层, 9 -电子注入层,
10-阴极层, 11 -外加电源; 41-第一空穴传输层,
42 -第二空穴传输层, 61 -第一子发光层,
62 -第二子发光层, 63 -第三子发光层。 具体实施方式
为使本发明实施例的目的、 技术方案和优点更加清楚, 下面将结合本发 明实施例的附图,对本发明实施例的技术方案进行清楚、 完整地描述。显然, 所描述的实施例是本发明的一部分实施例, 而不是全部的实施例。 基于所描 述的本发明的实施例, 本领域普通技术人员在无需创造性劳动的前提下所获 得的所有其他实施例, 都属于本发明保护的范围。
除非另作定义, 此处使用的技术术语或者科学术语应当为本发明所属领 域内具有一般技能的人士所理解的通常意义。 本发明专利申请说明书以及权 利要求书中使用的"第一" "第二 "以及类似的词语并不表示任何顺序、 数量或 者重要性, 而只是用来区分不同的组成部分。 同样, "一个 "或者 "一"等类似 词语也不表示数量限制, 而是表示存在至少一个。 "连接"或者"相连"等类似 的词语并非限定于物理的或者机械的连接, 而是可以包括电性的连接, 不管 是直接的还是间接的。
一般的, 定义真空或无限远处为能量零点, 所有的载流子所处的能级都 为负数。 在本发明实施例中, 能级值指的是取其绝对值后的值, 即用绝对值 的大小来描述能级的值, 例如真空或无限远处的能级值为 0, 低功函数值的 能级指的能级的绝对值(能级值)较小的能级, 高功函数值的能级指的是能 级的绝对值(能级值)较大的能级; 在能级图中比较时, 比较的是能级位置 的高低, 例如: 低功函数值的能级的位置高于高功函数值的能级的位置, 或 者说, 5ev能级值的能级的位置比 3ev能级值的能级的位置更低。
实施例 1 :
如图 2所示, 本实施例中, 该有机电致发光器件包括衬底 1、 阳极层 2、 阴极层 10、 以及设置在阳极层 2和阴极层 10之间的有机功能层。 本实施例 中, 所述有机功能层包括空穴注入层 3、 空穴传输层 4、 电子阻挡层 5、 发光 层 6、 空穴与激子阻挡层 7、 电子传输层 8和电子注入层 9。 在阳极层 2和阴 极层 10之间连接有外加电源 11 ,有机电致发光器件在外加电源 11的驱动下 发光。
当然,上述有机功能层中也可以不包括电子阻挡层 5和 /或空穴与激子阻 挡层 7。 即, 可替代地, 本实施例的有机电致发光器件包括衬底 1、 阳极层 2、 阴极层 10、 以及设置在阳极层 2和阴极层 10之间的有机功能层, 所述有机 功能层中可以只包括空穴传输层 4、发光层 6和电子传输层 8。或者, 可替代 地, 本实施例的有机电致发光器件包括衬底 1、 阳极层 2、 阴极层 10、 以及 设置在阳极层 2和阴极层 10之间的有机功能层,所述有机功能层中也可以只 包括发光层 6。
在本实施例中, 所述发光层 6包括三个依次相邻的子发光层, 即靠近阳 极层 2的第一子发光层 61、 靠近阴极层 10的第三子发光层 63、 以及位于第 一子发光层 61和第三子发光层 63之间的第二子发光层 62。
所述三个子发光层均釆用基质材料掺杂发光材料制成, 其中第二子发光 层 62的基质材料釆用混合基质材料,该混合基质材料由具有空穴传输能力的 基质材料和具有电子传输能力的基质材料混合制成,第一子发光层 61中的基 质材料釆用具有空穴传输能力的单基质材料,第三子发光层 63中的基质材料 釆用具有电子传输能力的单基质材料。
这里, 具有空穴传输能力的基质材料是指空穴传输能力强于电子传输能 力的基质材料, 具有电子传输能力的基质材料是指电子传输能力强于空穴传 输能力的基质材料。 换言之, 具有空穴传输能力可被定义为空穴的迁移率大 于电子的迁移率时的电荷传输能力, 并且可按照常规方法如飞行时间法进行 测定; 具有电子传输能力的基质材料或具有空穴传输能力可同理推之。
第一子发光层 61 的基质材料的 HOMO ( Highest Occupied Molecular
Orbital, 最高已占轨道) 的位置比第三子发光层 63的基质材料的 HOMO的 位置高 0.2ev 或以上, 第一子发光层 61 的基质材料的 LUMO ( Lowest Unoccupied Molecular Orbital, 最低未占轨道) 的位置比第三子发光层 63的 基质材料的 LUMO的位置高 0.2ev或以上。
第一子发光层 61中的基质材料可釆用芳香族二胺类化合物、三苯胺化合 物、 芳香族三胺类化合物、 联苯二胺衍生物或三芳胺聚合物。 本实施例中, 第一子发光层 61中的基质材料釆用: 9, 10-二 - ( 2-萘基)蒽(ADN ) 、 TAZ、 CBP、 MCP、 4,4',4"-三 (咔唑 -9-基)三苯胺( TCTA )或 Ν,Ν'-二苯基 -Ν,Ν'-二 (1- 萘基) -1 ( ΝΡΒ ) 。
第三子发光层 63中的基质材料可釆用金属配合物、咔唑类衍生物、咪唑 类衍生物、 邻菲罗林衍生物或蒽的衍生物。 本实施例中, 第三子发光层 63 中的基质材料釆用: 8-羟基喹啉铝(Alq3 ) 、 8-羟基喹啉锂 ( Liq ) 、 1 , 3 , 5-三( N-苯基 -2-笨并咪唑 -2 )苯( TPBI ) 、 BCP或 Bphen。
本实施例中,在第二子发光层 62的混合基质材料中,具有空穴传输能力 的基质材料釆用与第一子发光层 61中的基质材料相同的基质材料,具有电子 传输能力的基质材料釆用与第三子发光层 63中的基质材料相同的基质材料。 其中, 具有空穴传输能力的基质材料与具有电子传输能力的基质材料的混合 比例范围可以为 1:9-9:1 , 本实施例中, 该比例为 1:1。
第一子发光层 61、第二子发光层 62和第三子发光层 63中的发光材料可 釆用基于 Ir、 Pt、 Ru、 Cu的磷光材料。本实施例中,该磷光材料可釆用 FIrpic、 Fir6、 Fir 、 FIrtaz、 Ir(ppy)3、 IrPi、 Ir(ppy)2(acac)、 PtOEP、 (btp)2Iracac、 Ir(piq)2(acac)、 (MDQ)2Iracac等。
所述发光层的厚度范围可以为 3-300nm, 第一子发光层 61、 第二子发光 层 62以及第三子发光层 63的厚度范围均可以为 l-100nm。 本实施例中, 所 述第一子发光层 61、第二子发光层 62以及第三子发光层 63的厚度均可以为 10nm。
所述空穴传输层 4的能级与第一子发光层 61的基质材料的能级相匹配, 即空穴传输层 4的 HOMO的位置与第一子发光层 61的基质材料的 HOMO 的位置比较接近, 空穴传输层 4的 HOMO的位置比第一子发光层 61的基质 材料的 HOMO的位置高 0.5ev及以下, 以便于空穴能够顺利进入第一子发光 层 61; 所述电子传输层 8的能级与第三子发光层 63的基质材料的能级相匹 配,即电子传输层 8的 LUMO的位置与第三子发光层 63的基质材料的 LUMO 的位置比较接近, 电子传输层 8的 LUMO的位置比第三子发光层 63的基质 材料的 LUMO的位置低 0.5ev及以下, 以便于电子能够顺利进入第三子发光 层 63。 同时, 由于上述能级匹配关系, 降低了空穴载流子和电子载流子的注 入势垒, 有利于增加电子载流子和空穴载流子注入发光层的效率, 从而提高 了有机电致发光器件的发光效率。
优选地, 当空穴传输层包括两个或两个以上的子空穴传输层时, 紧邻发 光层的一个空穴传输层的 HOMO 的位置与第一子发光层 61 的基质材料的 HOMO的位置相差 (前者比后者高)不超过 0.2ev; 或者, 电子传输层包括 两个或两个以上的子电子传输层时, 紧邻发光层的一个电子传输层 8 的 LUMO的位置与第三子发光层 63的基质材料的 LUMO的位置相差(前者比 后者低) 不超过 0.2ev。 即, 紧邻发光层的空穴传输层的 HOMO的位置比第 一子发光层 61的基质材料的 HOMO的位置高 0.2ev及以下, 紧邻发光层的 电子传输层 8的 LUMO的位置比第三子发光层 63的基质材料的 LUMO的位 置低 0.2ev及以下。
进一步优选的是, 空穴传输层 4或紧邻发光层的一个空穴传输层釆用与 第一子发光层 61的基质材料相同的材料制成,所述电子传输层 8或紧邻发光 层的一个电子传输层釆用与第三子发光层 63的基质材料相同的材料制成。
本实施例中, 空穴与激子阻挡层 7与电子传输层 8可以釆用同种材料制 成, 且该材料的 HOMO 的位置要低于发光层中具有空穴传输能力的基质材 料的 HOMO的位置。 所述空穴与激子阻挡层 7、 电子传输层 8中可釆用邻菲 罗林衍生物, 噁唑衍生物, 噻唑衍生物, 咪唑衍生物, 金属配合物, 蒽的衍 生物。 具体可釆用: 8-羟基喹啉铝 (Alq3 ) 、 8-羟基喹啉锂 ( Liq ) 、 8-羟基 喹啉镓、 双 [2-(2-羟基苯基 -1)-吡啶]铍、 2- ( 4-二苯基) -5- ( 4-叔丁苯基) -1 , 3 , 4-噁二唑( PBD ) 、 1 , 3 , 5-三( N-苯基 -2-笨并咪唑 -2 )苯( TPBI ) 、 BCP、 Bphen等。
在某些情况下,空穴与激子阻挡层 7和电子传输层 8可以设置为同一层, 该层同时兼具空穴阻挡、 激子阻挡以及电子传输的作用。
本实施例中, 空穴传输层 4可釆用芳香族二胺类化合物、三苯胺化合物、 芳香族三胺类化合物、 联苯二胺衍生物、 三芳胺聚合物、 以及咔唑类聚合物 制成。 如 NPB、 TPD、 TCTA、 以及聚乙烯咔唑或者其单体。
电子阻挡层 5的材料的选用范围可以与空穴传输层 4的材料的选用范围 一致。
空穴注入层 3可釆用三苯胺化合物或者是有 P型掺杂的有机层或者是聚 合物制成, 如三 -[4- ( 5-苯基 -2-噻吩基)苯]胺、 4,4,4,,-三 [2-萘基 (苯基) tt] 三苯胺(2-TNATA ) 或者 4 , 4,, 4,,-三- ( 3-曱基苯基苯胺基)三苯胺( m- MTDATA ) 、 酞箐铜 ( CuPc ) 、 Pedot:Pss、 TPD或 F4TCNQ。
此外, 衬底 1作为电极层和有机功能层的依托, 在可见光区域有着良好 的透光性能,并具有一定的防水汽和氧气渗透的能力,有较好的表面平整性, 它可以是玻璃或柔性基片或 TFT背板, 其中柔性基片可釆用聚酯类、 聚酞亚 胺化合物中的一种材料或者较薄的金属制成。
阳极层 2作为该有机电致发光器件正向电压的连接层, 具有较好的导电 性能、 可见光透明性以及较高的功函数值。 阳极层 2通常釆用无机金属氧化 物(比如: 氧化铟锡 ITO、 氧化辞 ΖηΟ等)或有机导电聚合物(如 PEDOT: PSS, PANI等)或高功函数值的金属材料(比如: 金、 铜、 银、 铂等)制成。 阴极层 10作为该有机电致发光器件负向电压的连接层,具有较好的导电 性能和较低的功函数值。 阴极层 10通常釆用低功函数值的金属材料, 比如: 锂、 镁、 钙、 锶、 铝、 铟等, 或上述低功函数值的金属材料与铜、 金、 银的 合金制成。
在本实施例中,在发光层内部, 由于第二子发光层 62中的混合基质材料 中包括有 50%的具有电子传输能力的基质材料, 因而该混合基质材料的 HOMO的位置较第一子发光层 61的基质材料的 HOMO的位置低,因而能在 第一子发光层 61与第二子发光层 62的交界面处聚集部分空穴载流子;同时, 第一子发光层 61的基质材料的 LUMO的位置比第二子发光层 62的混合基质 材料的 LUMO的位置高, 因而在上述交界面处还能聚集部分电子载流子,所 以第一子发光层 61与第二子发光层 62的交界面能形成一个载流子复合区。 同理, 在第二子发光层 62与第三子发光层 63的交界面处也能形成一个载流 子复合区。 同时,在第二子发光层 62中, 由于其基质材料釆用具有混合了两 种不同载流子传输能力的基质材料, 例如: 具有 50%的空穴传输能力的基质 材料与 50%的电子传输能力的基质材料, 所以第二子发光层 62能同时传输 两种载流子, 而且载流子的复合区很宽, 这样一来, 发光层 6形成了一个很 宽的载流子复合区, 一方面减少了载流子、 激子聚集的浓度, 另一方面增加 了载流子复合的范围, 从而提高了有机电致发光器件的效率, 减少了高电流 密度下的效率降低。
在本实施例中, 如图 8所示, 该有机电致发光器件的制备方法, 包括以 下几个步骤。
S1 )清洗衬底
在本实施例中, 将衬底 1依次在清洗剂、 乙醇溶液、 丙酮溶液和去离子 水中进行清洗, 然后用干燥氮气进行干燥。
S2 )制作阳极层或阴极层
将衬底 1置于真空蒸发室中,进行阳极层 2或阴极层 10的制备或其他处 理。
在本实施例中, 即将衬底 1传送到真空蒸发室中, 在衬底 1上形成氧化 铟锡( ITO )薄膜,从而在衬底 1上形成有机电致发光器件的阳极层 2。其中, ITO薄膜的方块电阻为 25Ω/口。
当然, 在实际生产过程中, 为了提高生产效率, 可以将步骤 S1 )和步骤 S2 )提前完成, 形成相应的带有阳极层或阴极层的衬底, 以方便后续加工过 程中直接利用。
S3 )对所制作的阳极层或阴极层进行预处理
在本实施例中, 将制备好阳极层 2的衬底 1移入真空室中, 釆用氧气等 离子对阳极层 2进行预处理或者氩气等离子进行预处理, 以提高 ITO薄膜的 洁净度和表面平整度, 改善 ITO薄膜表面特性和提高其功函数值。
54 )制作有机功能层
具体地,是在处理后的阳极层 2或阴极层 10上制备有机功能层,其中所 述发光层 6包括三个子发光层。
在本实施例中, 将处理后的衬底 1移入真空室中, 然后进行有机功能层 的制备。 按照本实施例中有机电致发光器件的结构, 蒸镀顺序依次如下: 空 穴注入层 3、 空穴传输层 4、 电子阻挡层 5、 发光层 6、 空穴与激子阻挡层 7、 电子传输层 8和电子注入层 9。 其中, 发光层 6从下到上依次为第一子发光 层 61、第二子发光层 62和第三子发光层 63。所述发光层 6的制作过程包括:
1 )制作第一子发光层 61 , 所述第一子发光层由具有空穴传输能力的基 质材料掺杂发光材料制成;
2 )在所述第一子发光层上制作第二子发光层 62, 所述第二子发光层由 具有空穴传输能力的基质材料和具有电子传输能力的基质材料混合并掺杂发 光材料制成;
3 )在所述第二子发光层上制作第三子发光层 63, 所述第三子发光层由 具有电子传输能力的基质材料掺杂发光材料制成。
55 )制作阴极层或阳极层
在本实施例中, 有机功能层制作完成后, 将衬底 1置于高真空度条件下 进行阴极层 10的制备。
上述步骤 S2 ) -步骤 S5 ) 中涉及的构成有机电致发光器件中有机功能层 中的各层的蒸镀速率及厚度由设置在衬底附近的膜厚仪进行监测。
56 )封装
将制备完的有机电致发光器件传送到手操箱进行封装, 手操箱为惰性气 体氛围, 在本实施例中为氮气氛围。
S7 )测试
对制备完成后的有机电致发光器件的光电性能进行测试。
一种显示装置, 其包括上述的电致发光器件。
实施例 2:
如图 3所示, 本实施例的有机电致发光器件包括衬底 1、 阳极层 2、 阴极 层 10、 以及设置在阳极层 2和阴极层 10之间的有机功能层。 其中, 有机功 能层包括发光层 6, 发光层 6的结构与实施例 1中发光层 6结构相同, 即该 发光层中包含三个子发光层(复合区), 即第一子发光层 61、 第二子发光层 62和第三子发光层 63。
进一步地,第二子发光层 62的基质材料釆用混合基质材料,该混合基质 材料由具有空穴传输能力的基质材料和具有电子传输能力的基质材料混合而 成; 第一子发光层 61中的基质材料釆用具有空穴传输能力的基质材料; 第三 子发光层 63中的基质材料釆用具有电子传输能力的基质材料。
本实施例的有机电致发光器件中, 所述有机功能层中的空穴传输层 4包 括两个子空穴传输层,即所述空穴传输层包括第一空穴传输层 41和第二空穴 传输层 42, 第二空穴传输层 42紧邻发光层 6。 例如, 所述第一空穴传输层 41与空穴注入层 3相邻, 所述第二空穴传输层 42与第一子发光层 61相邻。
可替代地, 在图 3所示的基础上, 本实施例的有机电致发光器件的有机 功能层中也可以不包括空穴注入层 3。
可替代地, 在图 3所示的基础上, 本实施例中的有机电致发光器件的有 机功能层中可以不具有电子阻挡层 5。 当然, 在实际应用中也可以设置电子 阻挡层 5 , 而且, 电子阻挡层 5的材料选用与实施例 1中空穴传输层 4的材 料选用范围可以一致。
可替代地, 上述有机功能层中可以只包括空穴传输层 4、 发光层 6和电 子传输层 8。 所述空穴传输层包括第一空穴传输层 41和第二空穴传输层 42。
第一空穴传输层 41的制作材料与实施例 1中空穴传输层 4的制作材料相 同; 同时, 第二空穴传输层 42的 HOMO (最高已占轨道) 的位置与第一子 发光层 61的 HOMO的位置要较好匹配, 优选地, 二者的能级的位置相差不 超过 0.2ev, 也即第二空穴传输层 42的 HOMO的位置与所述第一子发光层 61的基质材料的 HOMO的位置相差不超过 0.2ev; 且第二空穴传输层 42与 第一子发光层 61中具有空穴传输能力的基质材料的 LUMO (最低未占轨道) 的位置要高于第二发光层 62中具有电子传输能力的基质材料的 LUMO的位 置。 即, 第二空穴传输层 42的 HOMO的位置比第一子发光层 61的基质材 料的 HOMO的位置高 0.2ev及以下。
优选地, 第二空穴传输层 42的制作材料与第一子发光层 61的基质材料 的制作材料相同, 即釆用具有空穴传输能力的材料。
另夕卜,在本实施例中, 紧邻发光层的电子传输层 8的 LUMO的位置比第 三子发光层 63的基质材料的 LUMO的位置低 0.2ev及以下。 优选地, 与第 三子发光层 63相邻的空穴与激子阻挡层 7以及电子传输层 8釆用与第三子发 光层 63的基质材料相同的材料, 即釆用具有电子传输能力的材料。
进一步地, 本发明的实施例中的空穴传输层 4可以包括两个及两个以上 的子空穴传输层, 所述子空穴传输层至少包括第一空穴传输层 41,和第二空 穴传输层 42, (未图示) , 所述第一空穴传输层 41,与所述空穴注入层相邻, 所述第二空穴传输层 42,紧邻所述第一子发光层。 第二空穴传输层 42,的 HOMO的位置比第一子发光层 61的基质材料的 HOMO的位置高 0.2ev及以 下, 优选地, 第二空穴传输层 42,釆用与所述第一子发光层的基质材料相同 的材料制成; 另外,所述电子传输层的 LUMO的位置比所述第三子发光层的 基质材料的 LUMO的位置低 0.2ev及以下, 优选地, 所述电子传输层釆用与 所述第三子发光层的基质材料相同的材料制成。
在本实施例中, 该有机电致发光器件的其他各层的结构均与实施例 1相 同, 这里不再赘述。
本实施例中, 该有机电致发光器件中各层的具体构成如下, 其具体各层 的制备材料 /及厚度如下: Glass/ITO/ 2-TNATA( 10 nm )/ NPB ( 20 nm )/ TCTA (10 nm) I TCTA: Ir(ppy)3 (10 nm)/ TCTA: TPBI: Ir(ppy)3 (10 nm)/ TPBI: Ir(ppy)3 (10 nm)/TPBI ( 40 nm ) / LiF ( 0.5 匪) / Al ( 200匪) 。 即, 衬底 1釆用 Glass 制成; 阳极层 2釆用 ITO制成; 空穴注入层 3釆用 2-TNATA制成, 其厚度 为 10nm; 第一空穴传输层 41釆用 NPB制成, 其厚度为 20nm; 第二空穴传 输层 42釆用 TCTA制成, 其厚度为 10nm; 第一子发光层 61釆用 TCTA: Ir(ppy)3制成, 其厚度为 10nm; 第二子发光层 62釆用 TCTA: TPBI: Ir(ppy)3 制成, 其厚度为 10nm; 第三子发光层 63釆用 TPBI: Ir(ppy)3制成, 其厚度为 10nm; 空穴与激子阻挡层 7兼做电子传输层 8釆用 TPBI制成, 其厚度为 40nm; 电子注入层 9釆用 LiF制成, 其厚度为 0.5nm; 阴极层 10釆用 A1制 成,其厚度为 200nm。其中,复合发光层中的三个子发光层中的发光材料(即 掺杂剂 ) 均釆用绿色磷光掺杂剂 Ir(ppy)3
本实施例中有机电致发光器件的制备方法包括如下步骤:
S1 )清洗衬底
利用清洗剂、 丙酮溶液和去离子水中依次对衬底 1进行超声清洗, 清洗 后用干燥氮气吹干。
S2 )制作阳极层或阴极层
将衬底 1传送到真空蒸发室中,真空蒸发室中的真空度设置为 2x l04Pa, 在衬底 1上形成氧化铟锡(ITO )薄膜,即形成有机电致发光器件的阳极层 2, 其中 ITO薄膜的方块电阻为 25Ω/口。
53 )对所制作的阳极层或阴极层进行预处理
本实施例中,将已形成阳极层 2的衬底 1进行紫外光处理 25分钟, 以提 高 ITO薄膜表面的洁净度和表面平整度,改善 ITO薄膜表面特性和提高其功 函数值。
54 )制作有机功能层
将处理后的衬底 1放进真空室中, 将真空室抽真空至 2x l04Pa后, 进行 蒸镀以形成有机功能层。
具体地, 本实施例中, 蒸镀顺序如下: 空穴注入层 3 : 釆用 2-TNATA 材料制作, 其厚度为 10 nm, 蒸镀速率为 0.08nm/s; 第一空穴传输层 41: 釆 用 NPB材料制作, 其厚度为 20 nm, 蒸镀速率为 0.08nm/s; 第二空穴传输层 42: 釆用 TCTA材料制作, 其厚度为 10 nm, 蒸镀速率为 0.08nm/s; 发光层 6中:第一子发光层 61 :基质材料釆用 TCTA材料,其中掺杂发光材料 Ir(ppy)3, 其厚度为 10 nm, 蒸镀速率为 0.08nm/s; 第二子发光层 62: 混合基质材料釆 用 TCTA与 TPBI的混合材料,其中掺杂发光材料 Ir(ppy)3,其厚度为 10 nm, 蒸镀速率为 0.08nm/s; 第三子发光层 63: 基质材料釆用 TPBI材料, 掺杂发 光材料 Ir(ppy)3, 其厚度为 10 nm, 蒸镀速率为 0.08nm/s; 空穴与激子阻挡层 7兼做电子传输层 8: 釆用 TPBI材料制作, 其厚度为 40 nm, 蒸镀速率为 0.08nm/s; 电子注入层 9: 釆用 LiF材料制作, 其厚度为 0.5nm, 蒸镀速率为 0.02nm/s。
55 )制作阴极层或阳极层
在真空度为 5χ 104的高真空度条件下进行蒸镀以制作阴极层 10。
其中, 阴极层 10: 釆用金属 A1制作, 其厚度为 200 nm, 蒸镀速率为
1.5nm/s。
上述步骤 S2 ) -步骤 S5 ) 中涉及的构成有机电致发光器件中有机功能层 中的各层的蒸镀速率及厚度由设置在衬底附近的膜厚仪进行监测。
56 )封装
将制备完的有机电致发光器件传送到手操箱进行封装, 手操箱为惰性气 体氛围, 本实施例中为釆用氮气氛围。
S7 )测试
对制备完成的有机电致发光器件的光电性能进行测试。
图 4所示为本实施例中的有机电致发光器件的电流密度-电流效率曲线。 与现有技术中的有机电致发光器件(比如:具体结构为: Glass/ITO/ 2-TNATA ( 10 匪) / NPB ( 20 匪) / TCTA (10 nm) / TCTA: Ir(ppy)3 (15 nm)/ TPBI: Ir(ppy)3 (15 nm)/TPBI ( 40 nm ) / LiF ( 0.5 nm ) / Al ( 200 nm ) )相比, 本实 施例中的有机电致发光器件中釆用了三个子发光层, 使得发光层中具有较宽 的复合区, 能有效地减少激子淬灭, 提高了有机电致发光器件的发光效率, 从图 4中可看出, 本实施例中的有机电致发光器件的电流效率明显高于现有 技术中的有机电致发光器件的电流效率。
图 6为本实施例中有机电致发光器件的能级结构示意图。 如图 6所示, 在本实施例中, 第一子发光层 61与第二子发光层 62的交界面以及第二子发 光层 62与第三子发光层 63的交界面有很明显的载流子势垒, 一部分载流子 被阻挡在这两个交界面处, 形成载流子复合区。 由于激子扩散长度一般小于 10nm, 所以激子一般不会扩散到未掺杂掺杂剂 (发光材料)的区域, 即激子 的主要复合区基本位于发光层内部, 因此减少了无辐射跃迁的激子数量, 避 免了无辐射衰减对有机电致发光器件的寿命影响, 同时也使有机电致发光器 件发光效率得到提高。另外,第二子发光层 62中由于能进行两种载流子的传 输, 因此第二子发光层 62中的载流子复合区较第一子发光层 61与第二子发 光层 62的交界面,以及第二子发光层 62与第三子发光层 63的交界面所形成 的复合区更宽。
本实施例的有机电致发光器件, 通过在发光层釆用具有不同的载流子传 输能力的基质材料划分为三个子发光层 ,使发光层具有更宽的复合区的同时, 还设置空穴传输层 4的能级与第一子发光层 61 的能级匹配、 电子传输层 8 的能级与第三子发光层 63的能级匹配,尤其是还增设了第二空穴传输层 42, 所述第二空穴传输层 42釆用与第一子发光层 61中具有空穴传输能力的基质 材料相同的制作材料, 这种结构减少了空穴传输层 4与发光层 6之间的空穴 的注入势垒, 保证空穴能有效地注入到发光层中; 同时空穴与激子阻挡层 / 电子传输层分别釆用与第三子发光层 63中的基质材料相同的制作材料,保证 了电子能有效地注入到发光层 6中, 极大地提高了有机电致发光器件的发光 效率。
实施例 3:
本实施例中有机电致发光器件与实施例 2中有机电致发光器件的结构相 同, 其与实施例 2的区别在于, 发光层中所釆用的发光材料不相同。 本实施 例中, 发光层中发光材料釆用的是碑光掺杂剂 IrPi, 此材料具有较短的三重 态寿命(小于 500纳秒) , 且三个子发光层中掺杂剂的含量均为 6%。
例如, 本实施例中有机电致发光器件的构成材料如下: Glass/ITO/ 2-TNATA( 10匪) / NPB( 20匪 )/ TCTA (10匪) I TCTA: IrPi(10匪) I TCTA: TPBI: IrPi (10匪)/ TPBI: IrPi(10匪) /TPBI ( 40匪) / LiF ( 0.5匪) / Al ( 200 nm ) 。 即, 本实施例发光层中三个子发光层为: 第一子发光层 61 釆用 TCTA:IrPi制成, 其厚度为 10nm; 第二子发光层 62釆用 TCTA:TPBI:IrPi制 成, 其厚度为 10nm; 第三子发光层 63釆用 TPBI:IrPi制成, 其厚度为 10nm。 其中的发光材料(掺杂剂 ) 均釆用 IrPi (绿色磷光掺杂剂 ) 。
图 5所示为本实施例中有机电致发光器件的亮度-电流效率曲线,从图中 可知, 本实施例中的有机电致发光器件的电流效率远高于现有技术中的有机 电致发光器件的电流效率。
图 7为实施例 3中有机电致发光器件结构的能级示意图。 从图中可以看 出, 这种有机电致发光器件具有较宽的复合区, 该复合区减少了载流子、 激 子聚集的浓度, 减少了激子的淬灭, 增加了空穴载流子和电子载流子的复合 几率。
本实施例中有机电致发光器件的其他层的结构、 以及制作方法均与实施 例 2相同, 这里不再赘述。
这里应该理解的是, 实施例 1-3中有机电致发光器件通过在发光层中设 置具有不同的载流子传输能力的基质材料从而形成多个子发光层的结构, 不 仅适用于实施例 1-3中所述的底发射型有机电致发光器件, 也同时适用于顶 发射型有机电致发光器件。
在本发明中, 有机电致发光器件中发光层设置为包括多个子发光层的复 合发光层, 使得空穴载流子和电子载流子分布在一个较宽的范围内, 增加了 载流子复合区的宽度, 降低了某一个区域的载流子、 激子聚集的浓度, 使得 激子分布范围较广、 密度较为均衡, 减少了激子的聚集, 减少了激子的淬灭; 同时, 由于在发光层中与相应的载流子传输层相接触的子发光层中的基质材 料釆用与载流子传输层相匹配的材料制成, 从而降低了载流子的注入势垒, 增加了电子载流子和空穴载流子注入发光层的效率, 增加了电子载流子和空 穴载流子的复合几率, 提高了载流子的利用效率, 最终提高了有机电致发光 器件的发光效率,保证了有机电致发光器件在高亮度下仍然具有高电流效率, 提高了有机电致发光器件的性能。
以上所述仅是本发明的示范性实施方式, 而非用于限制本发明的保护范 围, 本发明的保护范围由所附的权利要求确定。

Claims

权利要求书
1. 一种有机电致发光器件, 包括衬底、 阳极层、 阴极层以及设置在阳极 层和阴极层之间的有机功能层, 其中, 所述有机功能层包括发光层, 所述发 光层包括三个依次相邻的子发光层, 即靠近阳极层的第一子发光层、 第二子 发光层和靠近阴极层的第三子发光层。
2. 根据权利要求 1所述的有机电致发光器件, 其中, 所述三个子发光层 均釆用基质材料掺杂发光材料制成;
其中, 所述第二子发光层的基质材料釆用混合基质材料, 该混合基质材 料由具有空穴传输能力的基质材料和具有电子传输能力的基质材料混合而 成, 所述第一子发光层中的基质材料釆用具有空穴传输能力的基质材料, 所 述第三子发光层中的基质材料釆用具有电子传输能力的基质材料。
3. 根据权利要求 2所述的有机电致发光器件, 其中, 所述第一子发光层 的基质材料的 HOMO的位置比所述第三子发光层的基质材料的 HOMO的位 置高 0.2ev或以上, 所述第一子发光层的基质材料的 LUMO的位置比所述第 三子发光层的基质材料的 LUMO的位置高 0.2ev或以上。
4. 根据权利要求 2所述的有机电致发光器件, 其中, 所述第二子发光层 的混合基质材料中 , 具有空穴传输能力的基质材料釆用与所述第一子发光层 中的基质材料相同的基质材料, 具有电子传输能力的基质材料釆用与所述第 三子发光层中的基质材料相同的基质材料。
5. 根据权利要求 4所述的有机电致发光器件, 其中, 所述第二子发光层 的混合基质材料中, 具有空穴传输能力的基质材料与具有电子传输能力的基 质材料的混合比例范围为 1:9-9:1。
6. 根据权利要求 2所述的有机电致发光器件, 其中, 所述第一子发光层 中的基质材料以及所述第二子发光层中具有空穴传输能力的基质材料釆用芳 香族二胺类化合物、 三苯胺化合物、 芳香族三胺类化合物、 联苯二胺衍生物 或三芳胺聚合物; 所述第三子发光层中的基质材料以及所述第二子发光层中 具有电子传输能力的基质材料釆用金属配合物、 咔唑类衍生物、 咪唑类衍生 物、 邻菲罗林衍生物或蒽的衍生物; 所述第一子发光层、 所述第二子发光层 和所述第三子发光层中的发光材料釆用基于 Ir、 Pt、 Ru、 Cu的磷光材料。
7. 根据权利要求 6所述的有机电致发光器件, 其中, 所述第一子发光层 中的基质材料以及所述第二子发光层中具有空穴传输能力的基质材料釆用: 9, 10-二- ( 2-萘基) 蒽、 TAZ、 CBP、 MCP、 TCTA或 NPB; 所述第三子发 光层中的基质材料以及所述第二子发光层中具有电子传输能力的基质材料釆 用: 8-羟基喹啉铝、 8-羟基喹啉锂、 1 , 3, 5-三(N-苯基 -2-笨并咪唑 -2 )苯、 BCP或 Bphen。
8. 根据权利要求 1-7任一所述的有机电致发光器件, 其中, 所述发光层 的厚度范围为 3-300nm, 所述第一子发光层、 所述第二子发光层以及所述第 三子发光层的厚度范围为 1-100匪。
9. 根据权利要求 1-8任一所述的有机电致发光器件, 其中, 所述有机功 能层中还包括有空穴传输层和电子传输层, 所述空穴传输层位于与所述第一 子发光层相邻且靠近阳极的一侧, 所述电子传输层位于与所述第三子发光层 相邻且靠近阴极的一侧, 其中, 空穴传输层的能级与所述第一子发光层的基 质材料的能级相匹配; 所述电子传输层的能级与所述第三子发光层的基质材 料的能级相匹配。
10. 根据权利要求 9所述的有机电致发光器件, 其中, 所述空穴传输层 的 HOMO的位置比所述第一子发光层的基质材料的 HOMO的位置高 0.5ev 及以下, 所述电子传输层的 LUMO 的位置比所述第三发光层的基质材料的 LUMO的位置低 0.5ev及以下。
11. 根据权利要求 9所述的有机电致发光器件, 其中, 所述空穴传输层 包括两个或两个以上的子空穴传输层, 所述子空穴传输层至少包括第一空穴 传输层和第二空穴传输层, 所述第二空穴传输层与所述第一子发光层相邻, 所述第二空穴传输层的 HOMO 的位置比所述第一子发光层的基质材料的 HOMO的位置高 0.2ev及以下。
12. —种显示装置, 包括权利要求 1-11任一所述的电致发光器件。
13. 一种有机电致发光器件的制备方法, 包括制作发光层的步骤, 其中, 所述发光层的制作步骤包括:
1 )制作第一子发光层,所述第一子发光层由具有空穴传输能力的基质材 料掺杂发光材料制成;
2 )在第一子发光层上制作第二子发光层,所述第二子发光层由具有空穴 传输能力的基质材料和具有电子传输能力的基质材料混合并掺杂发光材料制 成;
3 )在第二子发光层上制作第三子发光层,所述第三子发光层由具有电子 传输能力的基质材料掺杂发光材料制成。
PCT/CN2012/083893 2012-06-04 2012-10-31 有机电致发光器件及其制备方法以及显示装置 WO2013181897A1 (zh)

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