WO2022143821A1 - Dispositif optoélectronique - Google Patents

Dispositif optoélectronique Download PDF

Info

Publication number
WO2022143821A1
WO2022143821A1 PCT/CN2021/142724 CN2021142724W WO2022143821A1 WO 2022143821 A1 WO2022143821 A1 WO 2022143821A1 CN 2021142724 W CN2021142724 W CN 2021142724W WO 2022143821 A1 WO2022143821 A1 WO 2022143821A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
hole transport
quantum dot
energy level
valence band
Prior art date
Application number
PCT/CN2021/142724
Other languages
English (en)
Chinese (zh)
Inventor
杨一行
周礼宽
王天锋
Original Assignee
Tcl科技集团股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tcl科技集团股份有限公司 filed Critical Tcl科技集团股份有限公司
Publication of WO2022143821A1 publication Critical patent/WO2022143821A1/fr

Links

Images

Classifications

    • 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
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • 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]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • 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

Definitions

  • the present application relates to the field of display technology, in particular to an optoelectronic device.
  • QLED Quantum dot light-emitting display technology
  • OLED organic light-emitting display
  • QLED is an active light-emitting technology, so it also has high luminous efficiency, fast response speed, high contrast, Wide viewing angle and other advantages.
  • QLED Due to the excellent material properties of quantum dots in QLED display technology, QLED has performance advantages over OLED in many aspects, such as: the emission of quantum dots is continuously adjustable and the emission width is extremely narrow, which can achieve a wider color gamut and higher Purity display; the inorganic material characteristics of quantum dots make QLED have better device stability; the driving voltage of QLED device is lower than that of OLED, which can achieve higher brightness and reduce energy consumption; at the same time, QLED display technology and printing display production process and The matching technology can realize the high-efficiency mass production preparation of large size, low cost, and rollability. Therefore, QLED is considered to be one of the preferred technologies for next-generation display screens that are thin, portable, flexible, transparent and high-performance in the future.
  • the device structure of QLED is more borrowed from OLED display technology, except that the light-emitting layer material is replaced by organic light-emitting material.
  • other functional layer materials such as charge injection layer or charge transport layer, often use existing materials in OLEDs.
  • the explanation of device physics in QLED devices, the selection and collocation of energy levels of functional layer materials, etc. also follow the existing theoretical system in OLED.
  • the application of the classical device physics conclusions obtained in the research of OLED devices to the QLED device system has indeed significantly improved the performance of QLED devices, especially the efficiency of QLED devices.
  • One of the purposes of the embodiments of the present application is to provide an optoelectronic device, which aims to solve the problem that it is difficult to simultaneously improve the optoelectronic efficiency and lifetime performance of the QLED device in the related art.
  • an optoelectronic device comprising: an anode, a hole transport layer on the anode, a quantum dot light-emitting layer on the hole transport layer, and a cathode on the quantum dot light-emitting layer , the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, the outer shell layer of the quantum dot material is ZnSeS, and the mobility of the hole transport material in the hole transport layer is higher than 1 ⁇ 10 -4 cm 2 /Vs.
  • the beneficial effect of the optoelectronic device provided by the embodiments of the present application is that the outer shell layer of the quantum dot is made of ZnSeS, and its band gap width is between ZnSe and ZnS.
  • the tunneling effect of carriers has less influence.
  • the valence band energy level of the ZnSeS shell material is between ZnSe and ZnS.
  • ⁇ E EML-HTL valence band top energy level difference
  • the required hole transport material The top energy level of the valence band is relatively shallow. Therefore, when the hole mobility of the HTL material is greater than or equal to 1 ⁇ 10 -4 cm 2 /Vs, it can simultaneously satisfy the construction of the hole injection barrier and ensure the efficiency of hole transport and injection into the quantum dot material.
  • FIG. 1 is a schematic structural diagram of the optoelectronic device provided by the first aspect of the present application.
  • FIG. 2 is a schematic structural diagram of the optoelectronic device provided by the second aspect of the present application.
  • FIG. 3 is a schematic structural diagram of the optoelectronic device provided by the third aspect of the present application.
  • FIG. 4 is a schematic structural diagram of the optoelectronic device provided by the fourth aspect of the present application.
  • FIG. 5 is a schematic structural diagram of the optoelectronic device provided by the fifth aspect of the present application.
  • FIG. 6 is a schematic structural diagram of the optoelectronic device provided by the sixth aspect of the present application.
  • FIG. 7 is a schematic structural diagram of the optoelectronic device provided by the seventh aspect of the present application.
  • FIG. 8 is a schematic structural diagram of the optoelectronic device provided by the eighth aspect of the present application.
  • FIG. 9 is a schematic structural diagram of the optoelectronic device provided by the ninth aspect of the present application.
  • FIG. 10 is a schematic structural diagram of the optoelectronic device provided by the tenth aspect of the present application.
  • FIG. 11 is a schematic structural diagram of the optoelectronic device provided by the eleventh aspect of the present application.
  • FIG. 12 is a schematic structural diagram of the optoelectronic device provided by the twelfth aspect of the present application.
  • FIG. 13 is a schematic structural diagram of the optoelectronic device provided by the thirteenth aspect of the present application.
  • FIG. 14 is a schematic diagram of a positive structure of a quantum dot light-emitting diode provided by an embodiment of the present application.
  • 15 is a schematic diagram of an inversion structure of a quantum dot light-emitting diode provided in an embodiment of the present application.
  • 16 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 1 to 7 of the present application;
  • 17 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 8 to 9 of the present application;
  • FIG. 18 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 10 to 11 of the present application;
  • FIG. 19 is a graph showing the relationship between the voltage and time of the quantum dot light-emitting diodes provided in Examples 12 to 14 of the present application;
  • FIG. 20 is a graph showing the relationship between the voltage and time of the quantum dot light-emitting diodes provided in Examples 15 to 19 of the present application;
  • FIG. 21 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 20 to 25 of the present application;
  • FIG. 22 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 26 to 28 of the present application;
  • FIG. 24 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 32 to 35 of the present application;
  • FIG. 25 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 36 to 38 of the present application;
  • FIG. 26 is a graph showing the relationship between voltage and time of the quantum dot light-emitting diodes provided in Examples 39 to 41 of the present application;
  • FIG. 27 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 39 to 41 of the present application;
  • FIG. 28 is a graph showing the relationship between voltage and time of the quantum dot light-emitting diodes provided in Examples 42 to 43 of the present application;
  • FIG. 29 is a test chart of the luminous lifetime of the quantum dot light-emitting diodes provided in Examples 42 to 43 of the present application.
  • At least one means one or more
  • plural items means two or more.
  • At least one item(s) below” or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s).
  • at least one (one) of a, b, or c or, “at least one (one) of a, b, and c” can mean: a,b,c,a-b( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.
  • ⁇ E HTL-HIL E HOMO,HTL -E HIL
  • ⁇ E EML-HTL E HOMO,EML -E HTL
  • all energy level/work function values are absolute values, and the absolute value of the energy level is large The energy level is deep, and the absolute value of the energy level is small, the energy level is shallow.
  • the key of this application is to simultaneously improve the lifetime and photoelectric efficiency of QLED devices.
  • the time of device efficiency test is usually short, so it characterizes the instantaneous state of the QLED device at the beginning of operation; while the device life characterizes the continuous operation of the device and enters into a stable state The ability to maintain device efficiency after state.
  • the injection rate of electrons into the light-emitting layer is usually faster than that of holes. Therefore, in order to balance and improve the recombination efficiency of holes and electrons in the light-emitting layer of a QLED device, a hole injection layer is usually set in the device, and the injection barrier between two adjacent functional layers is minimized to enhance the hole efficiency. injection efficiency, thereby improving carrier injection efficiency and reducing interfacial charge accumulation.
  • this method can only improve the photoelectric efficiency at the initial instant of the QLED device to a certain extent, but cannot improve the device life at the same time, and even reduces the device life.
  • QLED has some special mechanisms different from the OLED device system.
  • the mechanism is closely related to the performance of QLED devices, especially the device lifetime.
  • this application finds through research that: in the initial working state of the QLED device, the injection rate of electrons in the light-emitting layer is faster than that of holes, resulting in the negative charge of the quantum dot material. Factors such as ligand binding and Coulomb blocking effects are maintained.
  • the negatively charged state of the quantum dot material makes the injection of electrons more and more difficult during the continuous operation of the QLED device, resulting in an imbalance between the actual injection of electrons and holes in the light-emitting layer.
  • the negatively charged state of the quantum dot material also tends to be stable, that is, the electrons newly captured and bound by the quantum dots reach a dynamic balance with the electrons consumed by the radiative transition.
  • the injection rate of electrons into the light-emitting layer is much lower than that in the initial state, and the hole injection rate required to achieve the balance of charge injection in the light-emitting layer is actually relatively low.
  • the hole injection efficiency is still improved based on the theoretical system of traditional OLED devices, the use of deep-level hole transport layers can only form an instantaneous balance of charge injection in the initial stage of QLED device operation, and achieve high device efficiency at the initial instant.
  • the QLED device enters a stable working state, excessive hole injection will aggravate the unbalanced state of electrons and holes in the light-emitting layer of the device, and the efficiency of the QLED device cannot be maintained, and thus decreases. And this charge imbalance will continue to increase as the device continues to work, resulting in a corresponding rapid decline in the life of the QLED device.
  • the key to fine-tuning the carrier injection of holes and electrons on both sides of the device is: on the one hand , regulating the injection rate of holes to a lower rate, so that the injection rate of holes and the injection rate of electrons in the stable working state of the QLED device are balanced, and the recombination efficiency of the QLED device is improved.
  • the hole injection rate required for QLED devices in the actual stable operating state is lower than traditionally expected, carrier accumulation is prone to occur, causing irreversible damage to the device. Therefore, the influence of carrier accumulation on the device life should be avoided as much as possible, and the device life should be improved.
  • a first aspect of an embodiment of the present application provides an optoelectronic device, comprising: an anode, a hole transport layer on the anode, a quantum dot light-emitting layer on the hole transport layer, and a hole transport layer on the hole transport layer.
  • the cathode on the quantum dot light-emitting layer, the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, and the valence band top energy level difference between the outer shell layer material of the quantum dot material and the hole transport material in the hole transport layer is greater than or equal to 0.5eV .
  • a valence band top energy level difference greater than or equal to 0.5 eV is constructed between the outer shell layer material of the quantum dot material and the hole transport material, that is, E EML-HTL ⁇ 0.5 eV.
  • the hole injection efficiency is reduced by increasing the hole injection barrier, thereby balancing the injection balance of holes and electrons in the light-emitting layer.
  • the present application finds through research that at least an energy level barrier of ⁇ E EML-HTL ⁇ 0.5 eV is required to achieve high hole injection efficiency.
  • the hole injection barrier of ⁇ E EML-HTL ⁇ 0.5eV in the present application will not prevent holes from being injected, because the energy level of the outer shell of the quantum dots will be band-bended in the energized working state, and carriers can pass through.
  • the tunneling effect realizes the injection; thus, although this increase in the energy level barrier will cause a decrease in the carrier injection rate, it will not completely hinder the final injection of carriers.
  • Quantum dot materials are generally composed of groups II-IV, II-VI, II-V, III-V, III-VI, IV-VI, I-III-VI, II-IV-VI of the periodic table of elements.
  • the core-shell structure quantum dot material includes a core and an outer shell.
  • the quantum dot material of the core-shell structure includes an inner core, an outer shell layer, and an intermediate bridge layer between the inner core and the outer shell layer, and the intermediate bridge layer may be one layer or multiple layers.
  • the core material determines the luminescence performance
  • the shell material protects the luminescence stability of the core and facilitates the injection of carriers. Electrons and holes are injected into the core through the shell layer to emit light.
  • the band gap of the inner core is narrower than that of the outer shell, so the energy level difference between the valence band of the hole transport material and the inner core of the quantum dot is smaller than the energy level difference of the valence band of the hole transport material and the outer shell of the quantum dot. Therefore, the ⁇ E EML-HTL of the embodiment of the present application is greater than or equal to 0.5 eV, which can simultaneously ensure the effective injection of hole carriers into the inner core of the quantum dot material.
  • the specific structure and specific material type of the quantum dot material of the core-shell structure in the embodiments of the present application are described in detail in the following embodiments according to different application situations.
  • the valence band top energy level difference between the outer shell layer material of the quantum dot material and the hole transport material in the hole transport layer is 0.5-1.7 eV, that is, the ⁇ E EML-HTL is 0.5 eV-1.7 eV, and the quantum dot material is 0.5-1.7 eV.
  • the energy level barrier in this range constructed between the outer shell material and the hole transport material can be applied to device systems constructed of different hole transport materials and quantum dot materials to optimize the injection of electrons and holes in different device systems. balance.
  • ⁇ E EML-HTL different top valence band energy level differences ⁇ E EML-HTL can be set according to the specific material properties, and the carrier injection rate of holes and electrons on both sides of the light-emitting layer can be finely adjusted to balance the injection of holes and electrons.
  • the valence band top energy level difference between the shell layer material of the quantum dot material and the hole transport material is 0.5eV ⁇ 0.7eV
  • the hole transport material can be TFB, P12, P15
  • the materials are ZnSe, CdS, such as: TFB-ZnSe, P12/P15-CdS and other device systems.
  • the valence band top energy level difference between the shell layer material of the quantum dot material and the hole transport material is 0.7eV ⁇ 1.0eV
  • the hole transport material can be TFB, P09
  • the quantum dot shell material is ZnSe, CdS, such as: P09-ZnSe, TFB-CdS and other device systems.
  • the valence band top energy level difference between the outer shell layer material of the quantum dot material and the hole transport material is 1.0eV ⁇ 1.4eV
  • the hole transport material can be TFB, P09, P13, P14
  • the quantum The point shell materials are CdS, ZnSe, ZnS, such as: TFB-ZnS, P09-CdS, P13/P14-ZnSe and other device systems.
  • the difference in valence band top energy level between the outer shell layer material of the quantum dot material and the hole transport material is greater than 1.4 eV to 1.7 eV, and device systems such as P09-ZnS and P13/P14-ZnS can be used in this case.
  • a hole injection layer in the current device is often used to improve the hole injection efficiency
  • the QLED devices of some embodiments of the present application need to regulate the hole injection rate to a lower rate in a certain way. Therefore, in some specific embodiments, a hole injection layer may not be provided in the optoelectronic device provided in the first aspect of the embodiments of the present application.
  • the setting of the hole injection layer in the QLED device can not only improve the hole injection efficiency, but also adjust the stable and balanced injection of holes, which is one of the key factors affecting the performance and life of the device. Therefore, in the embodiments of the present application, the hole injection efficiency in the device can also be controlled by arranging a hole injection layer in the device, and the influence of charge accumulation on the life of the device can be reduced. specifically:
  • the voltage rise of the QLED device caused at this time is significantly different from the voltage rise caused by the charge accumulation at the EML interface as follows: the interface between the HIL and the HTL generates an electric field due to the charge accumulation, and the damage caused is usually irreversible, and the damage This can happen all the time as the device continues to be energized, i.e. it will continue to deteriorate; while the charge accumulation at the EML interface is reversible and will reach a certain degree of saturation. Therefore, the interfacial charge accumulation between HIL and HTL has a greater impact on the performance of the device, such as lifetime.
  • the embodiments of the present application optimize the injection and recombination efficiency of carriers in the QLED device.
  • an optoelectronic device is provided on the basis of the embodiments of the first aspect or independently.
  • the optoelectronic device includes a first hole injection layer, and the first hole injection layer is located in the Between the anode layer and the hole transport layer, the absolute value of the difference between the top energy level of the valence band of the hole transport layer material and the work function of the first hole injection material in the first hole injection layer is less than or equal to 0.2 eV.
  • the energy level barrier of hole injection between HTL and HIL can be significantly reduced, and the injection efficiency of holes from the anode can be improved, It is conducive to the effective injection of holes from HIL to HTL, eliminating potential barriers and interface charges, reducing the overall resistance of the device, thereby reducing irreversible damage caused by charge accumulation at the interface between HIL and HTL, reducing device driving voltage and improving device life. .
  • the absolute value of the difference between the valence band top energy level of the hole transport layer material and the work function of the first hole injection material is 0 eV.
  • in the examples of the present application is 0. At this time, the effective injection effect of holes from HIL to HTL is good, the potential barrier and interface charges are eliminated, and the overall resistance of the device is reduced, thereby reducing the driving voltage of the device and improving the life of the device. .
  • the absolute value of the work function of the first hole injection material is 5.3 eV ⁇ 5.6 eV
  • the absolute value of the valence band energy level of the hole injection material with the work function size is compared with that of the conventional hole transport material. Close to (about 5.4eV), it is beneficial to control
  • HIL and HTL materials with suitable energy levels, so that
  • the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 4 cm 2 /Vs.
  • the examples of the present application use hole transport materials with a mobility higher than 1 ⁇ 10 -4 cm 2 /Vs.
  • the inventors have found through numerous experiments that the use of hole transport materials with the above mobility can improve the hole transport and migration effect and prevent the Charge accumulation, eliminate interface charge, better reduce device driving voltage and improve device life.
  • a third aspect of the embodiments of the present application provides an optoelectronic device based on the first aspect or independently, comprising a second hole injection layer, and the second hole injection layer is located in the anode layer and the hole transport layer, the difference between the valence band top energy level of the hole transport layer material in the hole transport layer and the work function difference of the second hole injection material in the second hole injection layer is less than -0.2 eV.
  • the anode direction is increased.
  • the hole injection barrier of the HIL reduces the overall rate of hole injection in the QLED device and effectively controls the number of holes entering the QLED device. On the one hand, it effectively reduces the rate of hole injection into the light-emitting layer, balances the hole-electron injection rate in the light-emitting layer, and improves the carrier recombination efficiency; on the other hand, it can avoid excessive hole injection in HTL and HIL.
  • Charge accumulation is formed at the interface to prevent irreversible damage to the life of the device caused by the charge accumulation at the interface.
  • a hole blocking barrier from HTL to HIL is formed, which prevents holes from diffusing to the HIL layer, improves the utilization rate of holes, and ensures the effective "survival" of holes before being injected into the light-emitting layer.
  • the holes injected in the device are fully and effectively utilized, the luminous efficiency of the device is guaranteed, and the device efficiency and service life are improved at the same time.
  • the quantum dot material of the core-shell structure contained in the quantum dot light-emitting layer of the optoelectronic device has a valence band top energy level difference between the outer shell layer material and the hole transport material greater than 0 eV, that is, ⁇ E EML-HTL >0,
  • the energy level of the light-emitting layer is deeper than that of the hole transport layer; at the same time, there is an injection barrier less than -0.2eV between the hole transport layer material and the second hole injection material, that is, ⁇ E HTL-HIL ⁇ -0.2eV, the hole
  • the energy level of the injection layer is deeper than that of the hole transport layer.
  • a "deep-shallow-deep” energy level structure is formed between the light-emitting layer, the hole transport layer and the hole injection layer, so that the holes injected into the hole transport layer form a hole carrier well.
  • the accumulated holes are effectively "stored” without diffusing to other functional layers or interfaces other than the HTL layer. And eliminate the influence of the interface charge on the device, on the basis of ensuring the injection balance of carriers in the stable working state of the device, more fully and effectively use the holes injected in the device, ensure the luminous efficiency of the device, and realize the efficiency and life of the device. Simultaneously increase.
  • the valence band top energy level difference between the outer shell layer material of the quantum dot material and the hole transport material is greater than or equal to 0.5 eV; in some other specific embodiments, the outer shell layer material of the quantum dot material and the hole transport material
  • the energy level difference at the top of the valence band can also be 0.5eV ⁇ 1.7eV, that is, ⁇ E EML-HTL is 0.5eV ⁇ 1.7eV. It has been verified by experiments that the hole carrier trap formed by the above embodiment has a good effect. In the actual application process The injection balance of holes and electrons in the light-emitting layer of the device can be controlled more precisely through the hole carrier trap, thereby improving the carrier recombination efficiency.
  • the difference between the valence band top energy level of the hole transport layer material and the work function of the second hole injection material is -0.9eV ⁇ -0.2eV, and the difference between ⁇ E HTL-HIL is -0.9eV ⁇ - 0.2eV, in this range, the injection and transport of holes have a good balance effect. If it is lower than -0.9eV, the hole injection resistance will increase, resulting in a decrease in the amount of hole injection, which affects the balanced injection and effective recombination of holes and electrons in the light-emitting layer; Accumulation is formed, and the utilization rate is not high.
  • the absolute value of the work function of the second hole injection material is 5.4 eV ⁇ 5.8 eV.
  • the absolute value of the work function of the second hole injection material in the embodiment of the present application is 5.4 eV to 5.8 eV, which is favorable for forming a hole blocking barrier with an energy range of less than -0.2 eV with the hole transport material.
  • the absolute value of the valence band of the conventional hole transport material is about 5.3-5.4 eV
  • the second hole injection material with the absolute value of the work function greater than or equal to 5.4 eV can form a negative energy less than -0.2 eV with the conventional hole transport material level difference, thereby forming a hole blocking barrier, optimizing the hole injection rate, and improving the hole utilization rate.
  • the mobility of the hole transport material is higher than 1 ⁇ 10 -4 cm 2 /Vs
  • the embodiment of the present application adopts a hole transport material with a mobility higher than 1 ⁇ 10 -4 cm 2 /Vs to ensure that The transport and migration effect of holes prevents charge accumulation, eliminates interface charges, and better reduces device driving voltage and improves device life.
  • the hole injection material is selected from a metal oxide material. That is, in some embodiments, when the optoelectronic device includes a first hole injection layer, the first hole injection material in the first hole injection layer is selected from metal oxide materials. In other specific embodiments, when the optoelectronic device includes a second hole injection layer, the second hole injection material in the second hole injection layer is selected from metal oxide materials.
  • the metal oxide material used as the hole injection material has better stability and is not acidic, which not only meets the requirements for hole injection in the above embodiments, but also does not affect adjacent holes.
  • the functional layer has a negative impact. The decay of the life of the device caused by the thermal effect or the electrical effect damage of the organic hole injection material during the working process of the device is avoided, and the damage to the adjacent functional layer due to the acidity of the organic hole injection material is avoided.
  • the metal oxide material includes: at least one metal nanomaterial selected from tungsten oxide, molybdenum oxide, vanadium oxide, nickel oxide, and copper oxide, and these metal nanomaterials have good stability and are not acidic,
  • the size of the work function can be adjusted to achieve the construction of energy level barriers of different sizes with the hole transport layer, which is beneficial to control hole injection and transport, improve the carrier recombination efficiency, and reduce the effect of charge accumulation on the life of the device. Impact.
  • the particle size of the metal oxide material is 2 to 10 nm, and the metal oxide material with a small particle size is conducive to depositing a thin film with a dense film layer and a uniform thickness, which improves the bonding tightness with the adjacent functional layer. , reducing the interface resistance, which is beneficial to improve the device performance.
  • the hole injection material can also be poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), HIL2, HIL1-1, HIL1-2, copper phthalocyanine (CuPc), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane (F4-TCNQ), 2,3,6,7,10,11-hexa Organic hole injection materials such as cyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN).
  • PEDOT:PSS poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid
  • HIL2 HIL1-1, HIL1-2
  • CuPc copper phthalocyanine
  • F4-TCNQ 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane
  • HTCN 2,3,6,7
  • PEDOT:PSS contains the structural formula: The organic molecule of , its work function is -5.1eV; HIL2 contains the structural formula: The organic molecule of , its work function is -5.6eV; HIL1-1 and HIL1-2 both contain the structural formula: The work function of HIL1-1 is -5.4 eV and the work function of HIL1-2 is -5.3 eV.
  • the thickness of the first hole injection layer is 10-150 nm. In other embodiments, the thickness of the second hole injection layer is 10-150 nm.
  • the thickness of the hole injection layer of the present application can be flexibly adjusted according to actual application requirements, and at the same time, the hole injection rate can be better adjusted by adjusting the thickness of the hole injection layer.
  • a fourth aspect of the embodiment of the present application provides an optoelectronic device, the hole transport layer of the optoelectronic device contains at least two kinds of hole transport materials, wherein the valence band of at least one hole transport material is The absolute value of the top energy level is less than or equal to 5.3 eV.
  • the above-mentioned at least two hole transport materials include at least one hole transport material whose absolute value of the top energy level of the valence band is less than or equal to 5.3 eV and one type of hole transport material whose absolute value of the top energy level of the valence band is greater than 5.3 eV hole transport material.
  • the hole transport layer of the optoelectronic device provided in the fourth aspect of the present application is a mixed material layer comprising a plurality of hole transport materials with different valence band top energy levels, wherein the valence band top energy level of at least one hole transport material is less than or equal to 5.3 eV, while the shell energy level of conventional quantum dot light-emitting materials is often relatively deep (6.0 eV or deeper), therefore, an energy level difference greater than or equal to 0.5 eV is formed between the hole transport material with shallow energy level and the quantum dot shell material.
  • the included hole transport material whose absolute value of the top energy level of the valence band is greater than 5.3 eV can control the energy level difference between the hole transport material and the outer shell layer of the light emitting material in a small and fine manner. Therefore, in the hole transport layer, the hole transport material with an absolute value less than or equal to 5.3eV and a deep level hole transport material with an absolute value greater than 5.3eV can be matched with each other to realize the interaction between the hole transport material and the quantum hole transport material.
  • the fine tuning of the hole injection barrier between the dot shell layers can also be used to tune the hole mobility in the HTL layer through hole transport materials with different energy levels. Realize the energy level barrier of ⁇ E EML-HTL greater than or equal to 0.5eV.
  • the hole transport layer of the optoelectronic device contains at least two kinds of hole transport materials, wherein the absolute value of the valence band top energy level of one hole transport material is less than or equal to 5.3 eV, and also includes the valence band top The absolute value of the energy level is greater than 5.3 eV and less than 5.8 eV for hole transport materials.
  • the hole transport layer includes at least two hole transport materials, and the absolute value of the top energy level of the valence band of one hole transport material is less than or equal to 5.3 eV, and also includes the absolute value of the top energy level of the valence band. A hole transport material greater than or equal to 5.8eV.
  • the hole transport layer includes at least three hole transport materials, and the absolute value of the top energy level of the valence band of one hole transport material is less than or equal to 5.3 eV, and also includes the top energy level of the valence band.
  • the hole injection barrier can be flexibly adjusted according to practical application requirements, device systems and other factors, so that the injection energy level barrier of holes to the light-emitting material is greater than or equal to 0.5eV, reducing the injection efficiency of holes, so as to balance the injection balance of holes and electrons in the light-emitting layer, and the application is flexible and convenient.
  • the electron transport layer of the optoelectronic device may use a metal such as an organic electron transport material layer and ZnO nanoparticles. At least one of an oxide nanoparticle layer, a sputter deposited metal oxide layer.
  • the hole transport layer when the hole transport layer includes at least one hole transport material with a valence band top energy level of less than or equal to 5.3 eV and a valence band top energy level greater than 5.3 eV and less than 5.8 eV, the hole transport The layer has a relatively moderate top energy level of the valence band and hole mobility, so it can be well matched with conventional metal oxides such as ZnO or organic electron transport materials, which is beneficial to the regulation of the charge balance between holes and electrons.
  • metal oxide nanoparticles can be used in the electron transport layer of the optoelectronic device, and the surface groups are selected to be less connected. of metal oxide nanoparticles.
  • the hole transport layer includes a hole transport material whose valence band top energy level is greater than 5.8 eV, the energy level and mobility are both the same as the valence band top energy level of the aforementioned hole transport material.
  • the hole transport layer materials with a shallow valence band top energy level of less than or equal to 5.3eV have great differences, and continuous regulation in a large window range can be achieved through different mixing ratios, which is suitable for devices from the initial state to continuous operation to QLED device systems with more variable electron injection and transport changes during steady state, such as metal oxide nanoparticles with fewer surface groups attached.
  • the hole transport layer is a mixed material layer comprising hole transport materials of different energy levels, wherein the mass percentage of the hole transport materials with the absolute value of the top energy level of the valence band less than or equal to 5.3 eV is 30%. ⁇ 90%; this percentage of the shallow-level hole transport material can easily form a hole injection barrier greater than or equal to 0.5 eV with the shell layer of the light-emitting material. In practical applications, it can be flexibly adjusted according to the depth of the material energy level. The mixing ratio of materials of different energy levels. In some specific embodiments, when the absolute value of the top energy level of the valence band is less than or equal to 5.3 eV, the mass percentage content of the hole transport material is 50-60%, which has a good effect.
  • the hole transport layer is a mixed material layer comprising hole transport materials of different energy levels, wherein the mobility of at least one hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs, the present application
  • the high mobility of the hole transport material of the embodiment ensures the transport and mobility of holes, and reduces the accumulation of holes at the interface, which affects the performance of the device.
  • the top energy level of the valence band of the hole transport layer material with high hole mobility is relatively shallow, which also ensures the formation of a suitable energy range with the quantum dot shell material.
  • the hole transport layer is a mixed material layer comprising hole transport materials of different energy levels, wherein the mobility of at least one hole transport material is higher than 1 ⁇ 10 ⁇ 2 cm 2 /Vs. In other specific embodiments, the hole transport layer is a mixed material layer comprising hole transport materials of different energy levels, wherein the mobility of each hole transport material is higher than 1 ⁇ 10 -3 cm 2 /Vs .
  • the above-mentioned embodiments of the present application optimize the mobility of hole transport materials, ensure the hole transport efficiency, avoid charge accumulation affecting device performance, and ensure the combination of deep and shallow hole transport materials in the hole transport layer.
  • the injection barrier of the hole ensures the formation of an energy level barrier with ⁇ E EML-HTL greater than or equal to 0.5eV, and optimizes the injection balance and recombination efficiency of carriers in the QLED device.
  • a fifth aspect of the embodiment of the present application provides an optoelectronic device, wherein the hole transport layer of the optoelectronic device contains at least two kinds of hole transport materials, and the top energy level of the valence band of each hole transport material is The absolute value of is less than or equal to 5.3eV.
  • the hole transport layer of the optoelectronic device provided in the fifth aspect of the present application is a mixed material layer comprising a plurality of hole transport materials with different valence band top energy levels, wherein the valence band top energy level of each hole transport material is less than It is equal to 5.3eV, which can form an energy level difference of 0.5eV or more with the quantum dot light-emitting material with a deeper shell energy level.
  • the device ⁇ E EML-HTL ⁇ 0.5 eV. Therefore, after the QLED device enters a stable working state, the charge injection balance and the device efficiency are maintained, and the device life is optimized.
  • the hole mobility of the mixed hole transport layer can also be finely regulated by different mixing ratios by using the different hole mobilities of the hole transport layer materials that are also all of the hole transport layer materials with shallow valence band top energy levels.
  • the hole transport layer comprises a mixed material layer of hole transport materials of different energy levels, wherein the mass percentage of each hole transport material is 5-95%, and the mass percentage of each hole transport material is 5-95%. Mixing and matching of hole transport materials with different ratios has a good control effect on the hole mobility and injection barrier of the mixed hole transport layer.
  • the hole transport layer comprises a mixed material layer of hole transport materials of different energy levels, wherein at least one hole transport material has a mobility higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs, high hole transport
  • the high-efficiency hole transport layer material has a relatively shallow top energy level in the valence band.
  • the mobility of the hole transport material is limited, and the high mobility ensures the transport and mobility of holes, and at the same time ensures the formation of a more suitable injection barrier, so as to avoid the accumulation of holes at the interface and affect the device performance.
  • the mobility of at least one hole transport material in the hole transport layer is higher than 1 ⁇ 10 ⁇ 2 cm 2 /Vs.
  • the mobility of each hole transport material in the hole transport layer is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • the top energy level of the valence band of the hole transport material in the hole transport layer is all less than or equal to 5.3 eV
  • surface-passivated metal oxide nanoparticles are used in the electron transport layer of the optoelectronic device, and the surface is selected to be sufficiently modified and passivated. of metal oxide nanoparticles.
  • the top energy level of the valence band of the hole transport material in the hole transport layer is all less than or equal to 5.3 eV
  • the hole transport material is at least one selected from the group consisting of polymers containing aniline groups and copolymers containing fluorene groups and aniline groups, and these hole transport materials have holes It has the advantages of high transmission efficiency, good stability and easy access.
  • hole transport materials with suitable energy level and mobility can be selected according to the actual application requirements, specifically:
  • a hole transport material with an absolute value of valence band top energy level less than or equal to 5.3 eV can be selected: At least one of P09 and P13. Among them, the structural formula of P13 is: The structural formula of P09 is:
  • the transmission material includes: at least one of TFB, poly-TPD, and P11.
  • the structural formula of P11 is:
  • the structural formula of poly-TPD is:
  • the structural formula of TFB is:
  • the hole transport material with an absolute value of valence band top energy level greater than or equal to 5.8 eV includes: At least one of P15 and P12. Among them, the structural formula of P12 is: The structural formula of P15 is:
  • the mobility of the hole transport material is higher than 1 ⁇ 10 -4 cm 2 /Vs, and the high mobility ensures the transport and mobility of holes and reduces the effect of charge accumulation on the device lifetime.
  • the quantum dot material of the core-shell structure includes the outer shell layer, the inner core, and an intermediate shell layer located between the inner core and the outer shell layer; wherein, the top energy level of the valence band of the core material is shallower than that of the outer shell.
  • the valence band top energy level of the layer material; the valence band top energy level of the intermediate shell layer material is between the valence band top energy level of the core material and the valence band top energy level of the shell layer material.
  • the core material affects the luminescence performance
  • the shell material protects the luminescence stability of the core and facilitates carrier injection
  • the valence band is between the core and the shell layer.
  • plays an intermediate transition role which is conducive to carrier injection.
  • the intermediate shell layer can form a stepped energy level transition from the inner core to the outer shell layer in energy level, which is helpful to achieve effective carrier injection, effective confinement and Reduced flickering at lattice interfaces.
  • the outer shell layer of the quantum dot material includes: an alloy material formed by at least one or at least two of CdS, ZnSe, ZnTe, ZnS, ZnSeS, CdZnS, and PbS.
  • These shell layer materials not only protect the luminescence stability of the core and facilitate the injection of carriers into the quantum dot core for luminescence, but also form an energy level barrier with ⁇ E EML-HTL greater than or equal to 0.5eV with the HTL layer material.
  • the barrier can reduce the injection efficiency of holes, so as to balance the injection balance of holes and electrons in the light-emitting layer, improve the luminous efficiency of the device, and reduce the influence of charge accumulation on the life of the device.
  • the inner core of the quantum dot material includes: at least one of CdSe, CdZnSe, CdZnS, CdSeS, CdZnSeS, InP, InGaP, GaN, GaP, ZnSe, ZnTe, ZnTeSe.
  • the luminescent properties of quantum dot materials are related to the core materials. These materials ensure that QLED devices can emit light in the visible light range of 400-700 nm, which not only meets the range required for the application of optoelectronic display devices, but also the beneficial effects achieved by the energy level relationship of these materials can be achieved. better reflect.
  • the intermediate shell material is selected from at least one of CdZnSe, ZnSe, CdZnS, CdZnSeS, CdS, CdSeS.
  • the intermediate shell layer is selected to form a continuous natural transition from the inner core to the outer layer in the composition, which helps to achieve the least crystallinity among the inner core, the intermediate shell and the outer shell. Lattice mismatch and minimum lattice defects, so as to achieve the optimal luminescence performance of the core-shell quantum dot material itself.
  • the emission peak wavelength range of the quantum dot material is 400-700 nm. On the one hand, this wavelength range is required for the application of optoelectronic display devices; The beneficial effect can be better reflected.
  • the thickness of the outer shell layer of the quantum dot material is 0.2-6.0 nm, which covers the thickness of the conventional outer shell and can be widely used in QLED devices of different systems. If the thickness of the outer shell layer is too large, the rate at which carriers are injected into the light-emitting quantum dots through the tunneling effect will decrease; and if the thickness of the outer shell layer is too small, the outer shell material cannot sufficiently protect and passivate the core material. , which affects the luminescence and stability properties of quantum dot materials.
  • the optoelectronic device further includes an electron transport layer
  • the electron transport material in the electron transport layer is selected from at least one of metal oxo compound transport materials and organic transport materials.
  • metal oxide materials generally have high electron mobility, and can be prepared into thin films in QLED devices by solution method or vacuum sputtering method.
  • Organic electron transport layer materials can achieve energy level regulation in a wide range, and can be prepared into thin films in QLED devices by vacuum evaporation or solution methods; solution methods include inkjet printing, spin coating, jet printing , slot coating or screen printing, etc. More suitable electron transport materials can be flexibly selected according to actual application requirements.
  • the metal oxide transport material is selected from at least one of zinc oxide, titanium oxide, zinc sulfide, cadmium sulfide. These metal oxo compound transport materials used in the above embodiments of the present application all have high electron transfer efficiency. In some embodiments, in order to improve electron transfer efficiency, the metal oxo compound transport material is selected from at least one of zinc oxide, titanium oxide, zinc sulfide, and cadmium sulfide doped with metal elements, wherein the metal elements include aluminum, At least one of magnesium, lithium, lanthanum, yttrium, manganese, gallium, iron, chromium, and cobalt, these metal elements can improve the electron transfer efficiency of the material.
  • the particle size of the metal oxo compound transport material is less than or equal to 10 nm.
  • the metal oxy compound transport material with small particle size is more conducive to the deposition of electron transport layer films with dense film layers and uniform thickness. The tightness of its bonding with the adjacent functional layers reduces the interface resistance and is more conducive to improving the performance of the device.
  • the metal oxide compound transport material with small particle size has a wider band gap, which reduces the quenching of the exciton emission of the quantum dot material and improves the device efficiency.
  • the electron mobility of the metal oxo compound transport material is 10 -2 to 10 -3 cm 2 /Vs, and the electron transport material with high mobility can reduce the accumulation of charges in the interface layer, improve electron injection, compound efficiency.
  • the electron mobility of the organic transport material is not less than 10 ⁇ 4 cm 2 /Vs.
  • the organic transport material is selected from the group consisting of 8-quinolinolato-lithium (Alq 3 ), aluminum octaquinolate, fullerene derivatives PCBM, 3,5-bis(4-tert-butylphenyl) - At least one of 4-phenyl-4H-1,2,4-triazole (BPT), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) A sort of.
  • These organic transport materials can realize energy level regulation in a wide range, which is more conducive to regulating the energy levels of each functional layer of the device and improving the stability and photoelectric conversion efficiency of the device.
  • the electron transport layer is a laminated composite structure, which includes at least two sub-electron transport layers.
  • the electron transport layer can be regulated more flexibly to better optimize device performance.
  • the material of at least one sub-electron transport layer is a metal oxo compound transport material.
  • all sub-electron transport layers are metal oxides, and the metal oxide materials of different sub-electron transport layers may be the same or different. That is, in the multilayer electron transport layer in which all the sub-electron transport layers are metal oxides, there may be a sub-electron transport layer comprising at least one layer of metal oxide nanoparticles and at least one layer of non-nanoparticle type metal oxides. Sub electron transport layer.
  • the sub-electron transport layers can be doped and intrinsic metal oxides (eg, Mg-doped ZnO + intrinsic ZnO), respectively. It can also be that the sub-electron transport layers are all of the same metal oxide nanoparticles. When the sub-electron transport layers are all of the same metal oxide nanoparticle, the electron mobilities of different sub-electron transport layers may be the same or different.
  • the material of at least one sub-electron transport layer is an organic transport material. In some embodiments, in the electron transport layer, the material of at least one sub-electron transport layer is a metal oxo compound transport material, the material of at least one sub-electron transport layer is an organic transport material, and the metal oxide of different sub-electron transport layers
  • the metal oxide materials can be the same or different; the metal oxide materials are selected as nanoparticles of the corresponding metal oxide.
  • the electron transport layer has both high electron mobility and flexibility of energy level matching through the co-coordination of the metal oxo compound transport material and the organic transport material in the electron transport layer.
  • the electron transport layer comprising multiple sub-electron transport layers may be a combination of ZnO nanoparticles + NaF, a combination of Mg-doped ZnO nanoparticles + NaF, and other stacked composite structures.
  • the core material affects the luminescence properties of the quantum dot material
  • the shell material plays a protective role and is conducive to carrier injection.
  • the thickness of the shell layer and the top energy level of the valence band of the hole transport material can be adjusted so that the difference in the top energy level of the valence band between the shell layer material of the quantum dot material and the hole transport material is greater than or equal to 0.5 eV, that is, to construct the expected injection barrier, E EML-HTL ⁇ 0.5 eV, optimize the balance of electron and hole injection efficiency in the light-emitting layer, and improve the device efficiency and service life.
  • a sixth aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, and the quantum dot material has a core-shell structure.
  • the outer shell layer is ZnSe, and the absolute value of the top energy level of the valence band of the hole transport material in the hole transport layer is less than or equal to 5.4 eV.
  • the structure of the optoelectronic device is designed according to characteristics such as the energy level of ZnSe. Specifically, since the valence band energy level of the ZnSe shell material is relatively shallow (the absolute value of the energy level is small), to construct a hole injection barrier with a valence band top energy level difference ( ⁇ E EML-HTL ) greater than or equal to 0.5 eV, then The absolute value of the top energy level of the valence band of the hole transport material should be less than or equal to 5.4 eV.
  • a hole injection barrier is constructed, which reduces the hole injection rate, balances the injection efficiency of electron holes in the light-emitting layer, reduces the accumulation of carriers, and improves the luminous efficiency.
  • the thickness of the ZnSe shell layer is 2-5 nm. Due to the relatively narrow band gap of ZnSe in the embodiments of the present application, the binding ability of excitons in the quantum dot core is relatively poor.
  • the thickness of the outer shell layer is selected to be 2.0 to 5.0 nanometers. If the thickness of the outer shell layer is too large, the rate at which carriers are injected into the luminescent quantum dots through the tunneling effect will decrease; while the thickness of the outer shell layer is too small, the rate at which carriers are injected into the luminescent quantum dots through the tunneling effect will decrease. However, when the thickness of the outer shell layer is small to a certain extent, the outer shell layer structure will not be able to sufficiently protect and passivate the inner core, thereby affecting the luminescence performance and stability of the quantum dot material.
  • the emission peak wavelength of the quantum dot material is 510-640 nm.
  • the quantum dot light-emitting material should be a red or green quantum dot with a light-emitting peak wavelength range of 510-640 nanometers, so as to better ensure the light-emitting efficiency of the quantum dot.
  • the valence band top energy level difference between the ZnSe material and the hole transport material is 0.5-1.0 eV.
  • the energy level difference ( ⁇ E EML-HTL ) can be selected between 0.5 and 1.0 eV. If the ⁇ E EML-HTL is too large, the efficiency of hole injection into the luminescent core of the quantum dot will be reduced, and the luminous efficiency of the quantum dot material will be affected.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9 eV to 5.4 eV, within this range, a more suitable hole injection barrier can be constructed with the ZnSe shell material, and the load in the light-emitting layer can be optimized. Carrier injection and recombination efficiency.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9 eV to 5.4 eV, and at this time, the difference between the top energy levels of the valence band of the ZnSe material and the hole transport material is 0.5 to 1.0 eV.
  • the mobility of the hole transport material is higher than 1 ⁇ 10 -3 cm 2 /Vs. Since the absolute value of the top energy level of the valence band of the hole transport material used in the embodiments of the present application is less than or equal to 5.4 eV, Shallow energy level, the hole transport layer material with the shallower valence band top energy level usually has higher hole mobility, which is conducive to the efficient hole transport of holes in a certain thickness of the hole transport layer film, reducing the efficiency of the hole transport layer. The overall resistance of the device is reduced, thereby reducing the driving voltage of the device and improving the life of the device.
  • a seventh aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, and the quantum dot material has a core-shell structure.
  • the outer shell layer is ZnS, and the absolute value of the top energy level of the valence band of the hole transport material in the hole transport layer is less than or equal to 6.0 eV.
  • the structure of the optoelectronic device is designed according to characteristics such as the energy level of ZnS. Specifically, the valence band energy level of the ZnS shell material is deeper (relative to ZnSe, the absolute value of the energy level is larger), to construct a valence band top energy level difference ( ⁇ E EML-HTL ) greater than or equal to 0.5eV, the hole transport The top energy level of the valence band of the material may be less than or equal to 6.0 eV.
  • a hole injection barrier is constructed, which reduces the hole injection rate, balances the injection efficiency of electron holes in the light-emitting layer, reduces the accumulation of carriers, and improves the luminous efficiency.
  • the thickness of the ZnS shell is 0.2-2.0 nm. Due to the wide band gap of ZnS in the embodiment of the present application, the binding ability of excitons in the core of the quantum dot is relatively strong. Therefore, the thin ZnS shell layer thickness can basically ensure the good luminous efficiency of the quantum dot light-emitting material itself, and the shell layer The thickness is 0.2 to 2.0 nanometers. At the same time, the thin ZnS shell can also effectively reduce the overall resistance of the device, reduce the driving voltage of the device, and improve the performance of the device.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9 eV to 6.0 eV, within this range, a more suitable hole injection barrier can be constructed with the ZnS shell material, and the load in the light-emitting layer can be optimized. Carrier injection and recombination efficiency. In some embodiments, the absolute value of the valence band top energy level of the hole transport material is 4.9 eV to 5.5 eV.
  • the valence band top energy level difference between the ZnS material and the hole transport material is 1.0-1.6 eV.
  • the rate at which carriers are injected into the light-emitting quantum dots through the tunneling effect becomes stronger. Therefore, the corresponding hole transport layer material and the quantum dot shell layer in the quantum dot light-emitting layer are
  • the valence band top energy level difference ( ⁇ E EML-HTL ) of the material needs to be appropriately increased to better balance the injection balance of holes and electrons, and its range should be between 1.0-1.6 eV. If the ⁇ E EML-HTL should not be too large, the efficiency of hole injection into the luminescent core of the quantum dot will be reduced, and the luminous efficiency of the quantum dot material will be affected.
  • the emission peak wavelength of the quantum dot material is 400-700 nm. Due to the wide band gap of ZnS, the embodiment of the present application has a strong binding ability for excitons in the quantum dot core, which can effectively ensure the luminous efficiency of the quantum dot material itself. All quantum dot materials have a wide range of applications.
  • the hole mobility is relatively low, and the mobility of the hole transport material is higher than 1 ⁇ 10 -4 cm 2 /Vs. In some embodiments, the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • an eighth aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, and the quantum dot material has a core-shell structure.
  • the outer shell layer is CdZnS, and the absolute value of the top energy level of the valence band of the hole transport material in the hole transport layer is less than or equal to 5.9 eV.
  • the structure of the optoelectronic device is designed according to characteristics such as the energy level of CdZnS.
  • CdZnS is used as the outer shell layer of the quantum dot in this embodiment, and the valence band energy level is between ZnSe and ZnS, it is necessary to construct a hole injection potential with a valence band top energy level difference ( ⁇ EEML-HTL) greater than or equal to 0.5eV. barrier, the top energy level of the valence band of the hole transport material needs to be less than or equal to 5.9 eV.
  • the hole injection rate is reduced, the injection efficiency of electron holes in the light-emitting layer is balanced, the accumulation of carriers is reduced, and the light-emitting efficiency is improved.
  • the thickness of the CdZnS shell is 0.5 to 3.0 nm. Since the band gap of CdZnS is between ZnSe and ZnS, when the thickness of the shell is 0.5 to 3.0 nm, the excitons in the core of the quantum dot can be protected at the same time. binding ability, and the good luminous efficiency of the quantum dot luminescent material itself.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9-5.9 eV, within this range, a more suitable hole injection barrier can be constructed with the CdZnS shell material, and the current carrying in the light-emitting layer can be optimized. Sub-injection and recombination efficiency. In some embodiments, the absolute value of the valence band top energy level of the hole transport material is 4.9-5.5 eV.
  • the valence band top energy level difference between the CdZnS material and the hole transport material is 0.8-1.4 eV.
  • the valence band top energy level difference ( ⁇ E EML-HTL ) of the hole transport layer material in the embodiment of the present application and the quantum dot shell layer material in the quantum dot light-emitting layer ranges from 0.8 to 1.4 eV, which can ensure that carriers are injected through the tunneling effect To the efficiency of the luminescent quantum dots, it can better balance the injection efficiency of holes and electrons. If the ⁇ E EML-HTL is too large, the efficiency of carrier injection into the core of the light-emitting quantum dots through the tunneling effect is reduced; if the ⁇ E EML-HTL is too small, the injection rate of holes is poorly adjusted.
  • the emission peak wavelength of the quantum dot material is 400-700 nm. Since CdZnS has relatively strong binding ability to excitons in the quantum dot core, the embodiment of the present application can effectively ensure the luminous efficiency of the quantum dot material itself, and is suitable for all quantum dot materials in the visible light region with a luminous peak wavelength of 400-700 nm. Wide range of applications.
  • the hole mobility is relatively low, and the mobility of the hole transport material is higher than 1 ⁇ 10 -4 cm 2 /Vs. In some embodiments, the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • a ninth aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, wherein the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, and the quantum dot material has a core-shell structure.
  • the outer shell layer is ZnSeS, and the absolute value of the top energy level of the valence band of the hole transport material in the hole transport layer is less than or equal to 5.7 eV.
  • the structure of the optoelectronic device is designed according to characteristics such as energy levels of ZnSeS. Specifically, since ZnSeS is used as the outer shell layer of the quantum dot in this embodiment, and the valence band energy level is between ZnSe and ZnS, it is necessary to construct a hole injection potential with a valence band top energy level difference ( ⁇ EEML-HTL) greater than or equal to 0.5eV. barrier, the top energy level of the valence band of the hole transport material needs to be less than or equal to 5.7 eV. Through the constructed hole injection barrier, the hole injection rate is reduced, the injection efficiency of electron holes in the light-emitting layer is balanced, the accumulation of carriers is reduced, and the light-emitting efficiency is improved.
  • ⁇ EEML-HTL valence band top energy level difference
  • the thickness of the ZnSeS shell is 1.0-4.0 nm. Since the easily oxidized Se in the ZnSeS shell is closer to the surface of the quantum dots, the ZnSeS shell needs to be thicker to ensure sufficient protection and passivation for the core. , so that the thickness of the ZnSeS shell layer is 1.0-4.0 nm.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9-5.7 eV, within this range, a more suitable hole injection barrier can be constructed with the ZnSeS shell material, and the current carrying in the light-emitting layer can be optimized. Sub-injection and recombination efficiency. In some embodiments, the absolute value of the valence band top energy level of the hole transport material is 4.9-5.4 eV.
  • the valence band top energy level difference between the ZnSeS material and the hole transport material is 0.9-1.4 eV.
  • the valence band top energy level difference ( ⁇ E EML-HTL ) of the hole transport layer material and the quantum dot shell layer material in the quantum dot light-emitting layer in the embodiment of the present application is in the range of 0.9 to 1.4 eV, it is possible to ensure that the carriers pass through the tunneling effect.
  • the efficiency of injection into the light-emitting quantum dots can better balance the injection efficiency of holes and electrons. If the ⁇ E EML-HTL is too large, the efficiency of carrier injection into the core of the light-emitting quantum dots through the tunneling effect is reduced; if the ⁇ E EML-HTL is too small, the injection rate of holes is poorly adjusted.
  • the emission peak wavelength of the quantum dot material is 400-700 nm. Due to the relatively strong binding ability of ZnSeS to excitons in the quantum dot core, the embodiment of the present application can effectively ensure the luminous efficiency of the quantum dot material itself, and is suitable for all quantum dot materials in the visible light region with a luminous peak wavelength of 400-700 nm. Wide range of applications.
  • the hole mobility is relatively low, and the mobility of the hole transport material is higher than 1 ⁇ 10 -4 cm 2 /Vs. In some embodiments, the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • the hole transport material is at least one selected from the group consisting of polymers containing aniline groups and copolymers containing fluorene groups and aniline groups.
  • Hole transport materials with suitable mobility can be selected according to specific application requirements.
  • the aniline group-containing polymer with the absolute value of the top energy level of the valence band of the hole transport material less than or equal to 5.4 eV includes: poly-TPD, P9, TFB, P13.
  • the copolymer containing a fluorene group and an aniline group whose absolute value of the top energy level of the valence band of the hole transport material is less than or equal to 5.4 eV includes: TFB, P13.
  • the aniline group-containing polymers whose absolute value of the top energy level of the valence band of the hole transport material is greater than 5.4 eV and less than or equal to 5.9 eV include: P11, P12, and P15.
  • the copolymers containing fluorene groups and aniline groups whose absolute value of the top energy level of the valence band of the hole transport material is greater than 5.4 eV and less than or equal to 5.9 eV include: P12 and P15.
  • the quantum dot material of the core-shell structure includes the outer shell layer, the inner core, and an intermediate shell layer located between the inner core and the outer shell layer; wherein, the valence band of the core material is The top energy level is shallower than that of the outer shell material; the top energy level of the intermediate shell material is between the top energy level of the valence band of the core material and that of the outer shell material.
  • the core material is selected from Groups II-IV, II-VI, II-V, III-V, III-VI, IV-VI, I-III-VI, At least one of II-IV-VI and II-IV-V semiconductor compounds.
  • the core material is selected from at least one of CdSe, CdZnSe, CdSeS, CdZnSeS, InP, InGaP, GaP, ZnTe, and ZnTeSe. These core materials have good luminescence properties, and have a good coordination effect with the outer layer ZnSe, ZnS, CdZnS or ZnSeS.
  • the intermediate shell material is selected from at least one of CdZnSe, ZnSe, CdZnS, CdZnSeS, CdS, and CdSeS.
  • the matching principle of the middle shell layer in the embodiment of the present application is as follows: the composition of the middle shell layer preferably forms a continuous and natural transition from the inner core to the outer layer, which is helpful to realize the inner core, the middle shell layer and the outer shell layer. The least lattice mismatch and the least lattice defects between them, so as to achieve the optimal luminescence performance of the core-shell quantum dot material itself; the intermediate shell layer generally needs to form a stepped energy level from the core to the outer shell layer in terms of energy level. transition, which helps to achieve efficient carrier injection, efficient confinement and reduction of flickering at the lattice interface.
  • the optimization of the hole injection functional layer in the optoelectronic device in the second or third aspect can also be combined, and a first hole injection layer, a first hole injection layer and a second hole injection layer can be included.
  • the absolute value of the difference between the work function of the first hole injection material and the top energy level of the valence band of the hole transport material is less than or equal to 0.2 eV.
  • the difference between the top energy level of the valence band of the hole transport layer material and the work function of the second hole injection material in the second hole injection layer is less than -0.2 eV.
  • the utilization rate of holes in the device is improved, the hole injection rate is finely controlled, the carrier injection in the device is balanced, and the recombination efficiency is improved; at the same time, the influence of the charge accumulation in the interface layer on the life of the device is reduced.
  • an electron transport layer may also be included, and the electron transport layer includes at least two sub-electron transport layers arranged in layers; wherein, the material of at least one sub-electron transport layer is metal oxide family of compound transport materials. Alternatively, the material of at least one sub-electron transport layer is an organic transport material. Alternatively, the material comprising at least one sub-electron transport layer at the same time is a metal oxo compound transport material and the material of one sub-electron transport layer is an organic transport material.
  • a tenth aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a quantum dot material with a core-shell structure, and the quantum dot material has a core-shell structure.
  • the outer shell layer is ZnSe, and the mobility of the hole transport material in the hole transport layer is higher than 1 ⁇ 10 -3 cm 2 /Vs.
  • the valence band energy level of the ZnSe shell material is relatively shallow (the absolute value of the energy level is small) and the band gap is relatively narrow, the binding ability of the excitons in the core-shell structure of the quantum dot is relatively small. Poor, in order to ensure the good luminous efficiency of the quantum dot light-emitting material itself, a thicker ZnSe outer shell layer thickness is required, and the rate of injection into the light-emitting quantum dots through the tunneling effect becomes weaker.
  • E EML-HTL 0.5eV
  • HTL material with high hole mobility which is higher than 1 ⁇ 10 -3 cm 2 /Vs can compensate for the effect of tunneling effect on the hole injection rate, balance the injection efficiency of electron holes in the light-emitting layer, reduce the accumulation of carriers, and improve the luminous efficiency.
  • the thickness of the ZnSe shell layer is 2-5 nm. Due to the relatively narrow band gap of ZnSe in the embodiments of the present application, the binding ability of excitons in the quantum dot core is relatively poor.
  • the thickness of the outer shell layer is 2.0-5.0 nanometers. If the thickness of the outer shell layer is too large, the rate at which carriers are injected into the luminescent quantum dots through the tunneling effect will decrease; while the thickness of the outer shell layer is too small, the rate at which carriers are injected into the luminescent quantum dots through the tunneling effect will decrease. However, when the thickness of the outer shell layer is too small, the outer shell layer structure cannot sufficiently protect and passivate the inner core, thereby affecting the luminescence performance and stability of the quantum dot material.
  • the emission peak wavelength of the quantum dot material is 510-640 nm.
  • the luminous efficiency of the quantum dot material itself cannot be fully guaranteed even if a thick ZnSe outer layer is used.
  • the luminescent material should be red or green quantum dots with a luminescence peak wavelength range of 510-640 nm, so as to better ensure the luminous efficiency of the quantum dots.
  • the valence band top energy level difference between the ZnSe material and the hole transport material is 0.5-1.0 eV.
  • the rate at which carriers are injected into the light-emitting quantum dots through the tunneling effect is weakened.
  • the energy level difference ( ⁇ E EML-HTL ) should not be too large, and its range should be between 0.5 and 1.0 eV. If the ⁇ E EML-HTL should not be too large, the efficiency of hole injection into the luminescent core of the quantum dot will be reduced, and the luminous efficiency of the quantum dot material will be affected.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9 eV to 5.4 eV, within this range, a more suitable hole injection barrier can be constructed with the ZnSe shell material, and the loading in the light-emitting layer can be optimized. Carrier injection and recombination efficiency.
  • an eleventh aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a core-shell structure quantum dot material, and the quantum dot material
  • the outer shell layer is ZnS, and the mobility of the hole transport material in the hole transport layer is higher than 1 ⁇ 10 -4 cm 2 /Vs.
  • the thickness can basically ensure the good luminous efficiency of the quantum dot light-emitting material itself, so that the rate at which carriers are injected into the light-emitting quantum dots through the tunneling effect becomes stronger.
  • the hole mobility of the hole transport material used is greater than or equal to 1 ⁇ 10 -4 cm 2 /Vs, which can simultaneously realize that the difference in the top energy level of the valence band between the outer shell material of the quantum dot material and the hole transport material is greater than or equal to 0.5
  • the thickness of the ZnS shell is 0.2-2.0 nm. Due to the wide band gap of ZnS in the embodiment of the present application, the binding ability of excitons in the core of the quantum dot is relatively strong. Therefore, the thin ZnS shell layer thickness can basically ensure the good luminous efficiency of the quantum dot light-emitting material itself, and the shell layer The thickness is 0.2 to 2.0 nanometers. At the same time, the thin ZnS shell can also effectively reduce the overall resistance of the device, reduce the driving voltage of the device, and improve the performance of the device.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9 eV to 6.0 eV, within this range, a more suitable hole injection barrier can be constructed with the ZnS shell material, and the load in the light-emitting layer can be optimized. Carrier injection and recombination efficiency. In some embodiments, the absolute value of the valence band top energy level of the hole transport material is 4.9 eV to 5.5 eV.
  • the valence band top energy level difference between the ZnS material and the hole transport material is 1.0-1.6 eV.
  • the rate at which carriers are injected into the light-emitting quantum dots through the tunneling effect becomes stronger. Therefore, the corresponding hole transport layer material and the quantum dot shell layer in the quantum dot light-emitting layer are
  • the valence band top energy level difference ( ⁇ E EML-HTL ) of the material needs to be appropriately increased to better balance the injection balance of holes and electrons, and its range should be between 1.0 and 1.6 eV. If the ⁇ E EML-HTL should not be too large, the efficiency of hole injection into the luminescent core of the quantum dot will be reduced, and the luminous efficiency of the quantum dot material will be affected.
  • the emission peak wavelength of the quantum dot material is 400-700 nm. Due to the wide band gap of ZnS, the embodiment of the present application has a strong binding ability for excitons in the quantum dot core, which can effectively ensure the luminous efficiency of the quantum dot material itself. All quantum dot materials have a wide range of applications.
  • the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • a twelfth aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a core-shell structure quantum dot material, and the quantum dot material
  • the outer shell layer is CdZnS, and the mobility of the hole transport material in the hole transport layer is higher than 1 ⁇ 10 -4 cm 2 /Vs.
  • the outer shell layer of the quantum dot is CdZnS, and its band gap width is between ZnSe and ZnS.
  • the thickness of the layer can basically ensure the good luminous efficiency of the quantum dot light-emitting material itself, so the thickness of the outer shell layer has little influence on the tunneling effect of carriers.
  • the valence band energy level of the CdZnS shell material is between ZnSe and ZnS.
  • the hole injection barrier with ⁇ E EML-HTL ⁇ 0.5 eV can be constructed and the hole transport and injection into the quantum dot material can be ensured at the same time. s efficiency.
  • the thickness of the CdZnS shell is 0.5 to 3.0 nm. Since the band gap of CdZnS is between ZnSe and ZnS, when the thickness of the shell is 0.5 to 3.0 nm, the excitons in the core of the quantum dot can be protected at the same time. binding ability, and the good luminous efficiency of the quantum dot luminescent material itself.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9-5.9 eV, within this range, a more suitable hole injection barrier can be constructed with the CdZnS shell material, and the current carrying in the light-emitting layer can be optimized. Sub-injection and recombination efficiency. In some embodiments, the absolute value of the valence band top energy level of the hole transport material is 4.9-5.5 eV.
  • the valence band top energy level difference between the CdZnS material and the hole transport material is 0.8-1.4 eV.
  • the valence band top energy level difference ( ⁇ E EML-HTL ) of the hole transport layer material in the embodiment of the present application and the quantum dot shell layer material in the quantum dot light-emitting layer ranges from 0.8 to 1.4 eV, which can ensure that carriers are injected through the tunneling effect To the efficiency of the luminescent quantum dots, it can better balance the injection efficiency of holes and electrons. If the ⁇ E EML-HTL is too large, the efficiency of carrier injection into the core of the light-emitting quantum dots through the tunneling effect is reduced; if the ⁇ E EML-HTL is too small, the injection rate of holes is poorly adjusted.
  • the emission peak wavelength of the quantum dot material is 400-700 nm. Since CdZnS has relatively strong binding ability to excitons in the quantum dot core, the embodiment of the present application can effectively ensure the luminous efficiency of the quantum dot material itself, and is suitable for all quantum dot materials in the visible light region with a luminous peak wavelength of 400-700 nm. Wide range of applications.
  • the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • a thirteenth aspect of the embodiment of the present application provides an optoelectronic device, comprising a quantum dot light-emitting layer and a hole transport layer, the quantum dot light-emitting layer includes a core-shell structure quantum dot material, and the quantum dot material
  • the outer shell layer is ZnSeS, and the mobility of the hole transport material in the hole transport layer is higher than 1 ⁇ 10 -4 cm 2 /Vs.
  • the outer shell layer of the quantum dot is made of ZnSeS, and its band gap width is between ZnSe and ZnS.
  • the tunneling effect of the electrons has less influence.
  • the valence band energy level of the ZnSeS shell material is between ZnSe and ZnS.
  • ⁇ E EML-HTL valence band top energy level difference
  • the required hole transport material The top energy level of the valence band is relatively shallow. Therefore, when the hole mobility of the HTL material is greater than or equal to 1 ⁇ 10 -4 cm 2 /Vs, it can simultaneously satisfy the construction of the hole injection barrier and ensure the efficiency of hole transport and injection into the quantum dot material.
  • the thickness of the ZnSeS shell is 1.0-4.0 nm. Since the easily oxidized Se in the ZnSeS shell is closer to the surface of the quantum dots, the ZnSeS shell needs to be thicker to ensure sufficient protection and passivation for the core. , so that the thickness of the ZnSeS shell layer is 1.0-4.0 nm.
  • the absolute value of the top energy level of the valence band of the hole transport material is 4.9-5.7 eV, within this range, a more suitable hole injection barrier can be constructed with the ZnSeS shell material, and the current carrying in the light-emitting layer can be optimized. Sub-injection and recombination efficiency. In some embodiments, the absolute value of the valence band top energy level of the hole transport material is 4.9-5.4 eV.
  • the valence band top energy level difference between the ZnSeS material and the hole transport material is 0.9-1.4 eV.
  • the valence band top energy level difference ( ⁇ E EML-HTL ) of the hole transport layer material and the quantum dot shell layer material in the quantum dot light-emitting layer in the embodiment of the present application is in the range of 0.9 to 1.4 eV, it is possible to ensure that the carriers pass through the tunneling effect.
  • the efficiency of injection into the light-emitting quantum dots can better balance the injection efficiency of holes and electrons. If the ⁇ E EML-HTL is too large, the efficiency of carrier injection into the core of the light-emitting quantum dots through the tunneling effect is reduced; if the ⁇ E EML-HTL is too small, the injection rate of holes is poorly adjusted.
  • the emission peak wavelength of the quantum dot material is 400-700 nm. Due to the relatively strong binding ability of ZnSeS to excitons in the quantum dot core, the embodiment of the present application can effectively ensure the luminous efficiency of the quantum dot material itself, and is suitable for all quantum dot materials in the visible light region with a luminous peak wavelength of 400-700 nm. Wide range of applications.
  • the mobility of the hole transport material is higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs.
  • the hole transport material is at least one selected from the group consisting of polymers containing aniline groups and copolymers containing fluorene groups and aniline groups.
  • hole transport materials with appropriate mobility can be selected according to specific application requirements.
  • the aniline group-containing polymers having a mobility of the hole transport material higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs include: poly-TPD, TFB, P9, P11, P13.
  • the fluorene group and aniline group-containing copolymers with the mobility of the hole transport material higher than 1 ⁇ 10 ⁇ 3 cm 2 /Vs include: TFB, P13.
  • the aniline group-containing polymers having a mobility of the hole transport material higher than 1 ⁇ 10 ⁇ 4 cm 2 /Vs include: poly-TPD, TFB, P9, P11, P13, P15.
  • the fluorene group and aniline group-containing copolymers having a mobility of the hole transport material higher than 1 ⁇ 10 ⁇ 4 cm 2 /Vs include: TFB, P13, P15.
  • the quantum dot material of the core-shell structure further includes an inner core, and an intermediate shell layer located between the inner core and the outer shell layer; wherein, the top energy level of the valence band of the core material is shallow The valence band top energy level of the outer shell material; the valence band top energy level of the middle shell material is between the valence band top energy level of the core material and the valence band top energy level of the outer shell material.
  • the core material is selected from Groups II-IV, II-VI, II-V, III-V, III-VI, IV-VI, I-III-VI, At least one of II-IV-VI and II-IV-V semiconductor compounds.
  • the core material is selected from at least one of CdSe, CdZnSe, CdSeS, CdZnSeS, InP, InGaP, GaP, ZnTe, and ZnTeSe. These core materials have good luminescence properties, and have a good coordination effect with the outer layer ZnSe, ZnS, CdZnS or ZnSeS.
  • the intermediate shell material is selected from at least one of CdZnSe, ZnSe, CdZnS, CdZnSeS, CdS, and CdSeS.
  • the matching principle of the middle shell layer in the embodiment of the present application is as follows: the composition of the middle shell layer preferably forms a continuous and natural transition from the inner core to the outer layer, which is helpful to realize the inner core, the middle shell layer and the outer shell layer. The least lattice mismatch and the least lattice defects between them, so as to achieve the optimal luminescence performance of the core-shell quantum dot material itself; the intermediate shell layer generally needs to form a stepped energy level from the core to the outer shell layer in terms of energy level. transition, which helps to achieve efficient carrier injection, efficient confinement and reduction of flickering at the lattice interface.
  • the optimization of the hole injection functional layer in the optoelectronic devices in the second or third aspects can also be combined, and a first hole injection layer, a first hole injection layer, and a first hole injection layer can be included.
  • the absolute value of the difference between the work function of the first hole injection material of the layer and the top energy level of the valence band of the hole transport material is less than or equal to 0.2 eV.
  • a second hole injection layer is included, and the difference between the top energy level of the valence band of the material of the hole transport layer and the work function of the second hole injection material in the second hole injection layer is less than -0.2 eV.
  • the utilization rate of holes in the device is improved, the hole injection rate is finely controlled, the carrier injection in the device is balanced, and the recombination efficiency is improved; at the same time, the influence of charge accumulation in the interface layer on the life of the device is reduced.
  • an electron transport layer may also be included, and the electron transport layer includes at least two sub-electron transport layers arranged in layers; wherein, the material of at least one sub-electron transport layer is metal Oxygen compound transport material. Alternatively, the material of at least one sub-electron transport layer is an organic transport material. Alternatively, the material comprising at least one sub-electron transport layer at the same time is a metal oxo compound transport material and the material of one sub-electron transport layer is an organic transport material.
  • the device is not limited by the device structure, and may be a device with a positive structure or a device with an inversion structure.
  • the positive structure optoelectronic device includes a stacked structure of oppositely disposed anode and cathode, a light-emitting layer disposed between the anode and the cathode, and the anode disposed on the substrate.
  • a hole functional layer such as a hole injection layer and a hole transport layer can also be set between the anode and the light-emitting layer; and an electron functional layer such as an electron transport layer and an electron injection layer can also be set between the cathode and the light-emitting layer, as shown in Figure 14 shown.
  • the optoelectronic device includes a substrate, an anode disposed on the surface of the substrate, a hole transport layer disposed on the surface of the anode, a light emitting layer disposed on the surface of the hole transport layer, An electron transport layer on the surface of the layer and a cathode disposed on the surface of the electron transport layer.
  • the inversion structure optoelectronic device comprises a stacked structure of oppositely disposed anode and cathode, a light-emitting layer disposed between the anode and the cathode, and the cathode disposed on the substrate.
  • a hole functional layer such as a hole injection layer and a hole transport layer can also be set between the anode and the light-emitting layer; and an electron functional layer such as an electron transport layer and an electron injection layer can also be set between the cathode and the light-emitting layer, as shown in Figure 15 shown.
  • the optoelectronic device includes a substrate, a cathode disposed on the surface of the substrate, an electron transport layer disposed on the surface of the cathode, a light emitting layer disposed on the surface of the electron transport layer,
  • the hole transport layer is an anode disposed on the surface of the hole transport layer.
  • the choice of the substrate is not limited, and a rigid substrate or a flexible substrate may be used.
  • the rigid substrate includes, but is not limited to, one or more of glass and metal foil.
  • the flexible substrate includes, but is not limited to, polyethylene terephthalate (PET), polyethylene terephthalate (PEN), polyetheretherketone (PEEK), polystyrene (PS), polyethersulfone (PES), polycarbonate (PC), polyarylate (PAT), polyarylate (PAR), polyimide (PI), polyvinyl chloride (PV), poly One or more of ethylene (PE), polyvinylpyrrolidone (PVP), and textile fibers.
  • PET polyethylene terephthalate
  • PEN polyethylene terephthalate
  • PEEK polyetheretherketone
  • PS polystyrene
  • PS polyethersulfone
  • PC polycarbonate
  • PAT polyarylate
  • PAR polyarylate
  • PI polyimide
  • PV polyviny
  • the choice of anode material is not limited and can be selected from doped metal oxides, including but not limited to indium doped tin oxide (ITO), fluorine doped tin oxide (FTO), antimony doped tin oxide (ATO), Aluminum-Doped Zinc Oxide (AZO), Gallium-Doped Zinc Oxide (GZO), Indium-Doped Zinc Oxide (IZO), Magnesium-Doped Zinc Oxide (MZO), Aluminum-Doped Magnesium Oxide (AMO) one or more.
  • doped metal oxides including but not limited to indium doped tin oxide (ITO), fluorine doped tin oxide (FTO), antimony doped tin oxide (ATO), Aluminum-Doped Zinc Oxide (AZO), Gallium-Doped Zinc Oxide (GZO), Indium-Doped Zinc Oxide (IZO), Magnesium-Doped Zinc Oxide (MZO), Aluminum-Doped Magnesium Oxide (AMO)
  • the cathode material may be one or more of various conductive carbon materials, conductive metal oxide materials, and metallic materials.
  • conductive carbon materials include, but are not limited to, doped or undoped carbon nanotubes, doped or undoped graphene, doped or undoped graphene oxide, C60, graphite, carbon fiber, many Empty carbon, or a mixture thereof.
  • the conductive metal oxide material includes, but is not limited to, ITO, FTO, ATO, AZO, or mixtures thereof.
  • the metal materials include, but are not limited to, Al, Ag, Cu, Mo, Au, or their alloys; among the metal materials, their forms include but are not limited to dense films, nanowires, nanospheres, nanometers Rods, nano cones, nano hollow spheres, or their mixtures; the cathode is Ag, Al.
  • the quantum dot light-emitting layer has a thickness of 8-100 nm. In some embodiments, the hole transport layer has a thickness of 10-150 nm. In some embodiments, the electron transport layer has a thickness of 10-200 nm. In practical applications, the electron functional layer, the light emitting layer, and the hole functional layer in the device can be designed with appropriate thicknesses according to the characteristics of the device in the above embodiments.
  • a hole injection layer is grown on the surface of the anode
  • an electron transport layer is deposited on the quantum dot light-emitting layer, and a cathode electrode is evaporated on the electron transport layer to obtain an optoelectronic device.
  • step S10 the ITO substrate needs to undergo a pretreatment process, and the steps include: cleaning the ITO conductive glass with a detergent to preliminarily remove the stains existing on the surface, and then sequentially soaking in deionized water, acetone, anhydrous ethanol, and deionized water. Ultrasonic cleaning was carried out for 20 min to remove impurities on the surface, and finally dried with high-purity nitrogen to obtain the ITO positive electrode.
  • the step of growing the hole injection layer includes: preparing a metal oxide and other materials into a thin film in the QLED device by a solution method, a vacuum sputtering method, and a vacuum evaporation method; wherein, the solution method method Including inkjet printing, spin coating, spray printing (spray printing), slot-die printing (slot-die printing) or screen printing (screen printing) and the like.
  • the step of growing the hole transport layer includes: placing the ITO substrate on a spin coater, and using the prepared solution of the hole transport material to spin to form a film; adjusting the concentration of the solution and the spin coating speed and spin coating time to control the film thickness, followed by thermal annealing at an appropriate temperature.
  • the step of depositing the quantum dot light-emitting layer on the hole transport layer includes: placing the substrate on which the hole transport layer has been spin-coated on a spin coater, and spinning a solution of a prepared light-emitting substance with a certain concentration. Coating into a film, controlling the thickness of the light-emitting layer by adjusting the concentration of the solution, the spin coating speed and the spin coating time, about 20-60 nm, and drying at an appropriate temperature.
  • the step of depositing the electron transport layer on the quantum dot light-emitting layer includes: placing the substrate on which the quantum dot light-emitting layer has been spin-coated on a spin coater, and preparing a certain concentration of electron transport composite material
  • the solution is spin-coated to form a film by drip coating, spin coating, soaking, coating, printing, evaporation and other processes, and is controlled by adjusting the concentration of the solution, the spin coating speed (for example, the rotation speed is between 3000 and 5000 rpm) and the spin coating time.
  • the thickness of the electron transport layer is about 20 to 60 nm, and then annealed under the conditions of 150 ° C to 200 ° C to form a film, and the solvent is fully removed.
  • the steps of preparing the cathode include: placing the substrate on which each functional layer has been deposited into an evaporation chamber and thermally vapor-depositing a layer of 60-100 nm metal silver or aluminum as a cathode through a mask.
  • the method for preparing an optoelectronic device further includes encapsulating the laminated optoelectronic device; the curing resin used in the encapsulation is acrylic resin, acrylate resin or epoxy resin; resin curing adopts UV irradiation, Heat or a combination of both.
  • the encapsulation process can be done by conventional machine encapsulation or manual encapsulation. In the packaging process environment, the oxygen content and water content are both lower than 0.1ppm to ensure the stability of the device.
  • the method for preparing an optoelectronic device further includes, after encapsulating the optoelectronic device, introducing one or more processes including ultraviolet irradiation, heating, positive and negative pressure, applied electric field, and applied magnetic field; applying a process
  • the atmosphere can be air or an inert atmosphere.
  • the device of the embodiment of the present application adopts the ITO/HIL/HTL/QD/ETL/AL structure, and a certain heating treatment is performed after packaging.
  • the advantages of the technical solution of the present application are explained in detail by comparing the collocation and comparison of different functional layers in the device.
  • the life test adopts the constant current method, under the constant current of 50mA/ cm2 , the silicon photosystem is used to test the brightness change of the device, and the time when the brightness of the device starts from the highest point and decays to 95% of the highest brightness is recorded LT95, Then extrapolate the 1000nit LT95S life of the device through the empirical formula. This method is convenient for comparing the lifetime of devices with different brightness levels, and has a wide range of applications in practical optoelectronic devices.
  • the energy level test method of each material in the examples of the present application after spin-coating each functional layer material to form a film, the energy level test is carried out by UPS (ultraviolet photoelectron spectroscopy) method.
  • UPS ultraviolet photoelectron spectroscopy
  • Valence band top VB(HOMO): E HOMO E F-HOMO + ⁇ , where E F-HOMO is the difference between the material HOMO(VB) and the Fermi level, corresponding to the first occurrence of the low binding energy end in the binding energy spectrum the starting edge of a peak;
  • E LOMO E HOMO -E HOMO-LOMO
  • E HOMO-LOMO is the band gap of the material, obtained from UV-Vis (ultraviolet absorption spectrum).
  • this application sets up Examples 1 to 7.
  • the effect of hole injection barrier on performance such as device lifetime.
  • the two kinds of quantum dots used in Examples 1 to 7 of the present application are: blue QD1 whose outer shell is CdZnS (the inner core is CdZnSe, the middle shell is ZnSe, the outer shell thickness is 1.5 nm, and the top energy level of the valence band is -6.2 eV) , blue QD2 with ZnS outer shell (the inner core is CdZnSe, the middle shell is ZnSe, the ZnS shell thickness is 0.3 nm, and the top energy level of the valence band is 6.5 eV).
  • the blue QD3 with ZnSeS shell (the inner core is CdZnSe, the middle shell is ZnSe), the hole transport materials are P9 (E HOMO : 5.1 eV), P15 (E HOMO : 5.8 eV), and the hole injection layer is PEDOT:PSS (E HOMO : 5.1eV), the electron transport layer adopts ZnO, as shown in Table 1 below:
  • the ⁇ E EML-HTL barrier difference increases from 0.4eV to 0.7eV, and the device lifetime is significantly improved
  • the 1000nit LT95S life is increased from 0.72 to 6.29.
  • the device injection balance is optimized, and the device lifetime can be enhanced. It shows that reducing the hole injection efficiency by increasing the hole injection barrier can better balance the injection balance of holes and electrons in the light-emitting layer, and improve the luminous efficiency and luminous life of the device.
  • this application sets up Examples 8 to 11, through the comparison of different HTL and HTL, to illustrate the effect of the ⁇ E HTL-HIL hole injection barrier on the device life. and other performance effects.
  • blue quantum dots whose outer shell is ZnS (the inner core is CdZnSe, the middle shell is ZnSe, the outer shell thickness is 0.3 nm, and the top energy level of the valence band is 6.5 eV) are used, and in Examples 10 to 11
  • the red quantum dots with the outer shell of ZnS (the core is CdZnSe, the middle shell is ZnSe, the shell thickness is 0.3 nm, and the top energy level of the valence band is 6.5 eV) are used, and the hole transport materials are P9 (E HOMO : 5.5 eV), P11 (E HOMO : 5.5eV), P13 (E HOMO : 4.9eV), the hole injection layer adopts PEDOT:PSS (E HOMO : 5.1eV) and HIL2 (work function: 5.6eV), and the electron transport layer adopts ZnO.
  • Table 2 shows that
  • the present application sets up Examples 12 to 19, through the comparison of different HTL and HTL, to illustrate the
  • blue quantum dots whose outer shell is ZnS (the inner core is CdZnSe, the middle shell is ZnSe, the outer shell thickness is 0.3 nm, and the top energy level of the valence band is 6.5 eV) are used, and in Examples 15 to 19
  • the red quantum dots with the outer shell of ZnS (the core is CdZnSe, the middle shell is ZnSe, the shell thickness is 0.3 nm, and the top energy level of the valence band is 6.5 eV) are used, and the hole transport materials are P9 (E HOMO : 5.5 eV), P13 (E HOMO : 4.9 eV), TFB (E HOMO : 5.4 eV), the hole injection layer adopts PEDOT: PSS (E HOMO : 5.1 eV), HIL1-1 (work function: 5.4 eV) and HIL1-2 (work function: 5.4 eV) letter: 5.3eV), the electron
  • this application sets up Examples 20 to 25.
  • the HTL materials can build a hole injection barrier, optimize the carrier recombination efficiency and Impact on device life and other performance.
  • blue quantum dots with ZnS outer shells (the inner core is CdZnSe, the middle shell is ZnSe, the outer shell thickness is 0.3 nm, and the top energy level of the valence band is 6.5 eV) are used, and the hole transport materials are respectively P12 (E HOMO : 5.8eV), P13 (E HOMO : 4.9eV), TFB (E HOMO : 5.4eV), the hole injection layer adopts PEDOT:PSS (E HOMO : 5.1eV), as shown in Table 4 below:
  • the deep-level HTL can reduce the brightness change in the lifetime test caused by the exciton transfer of the HTL and QD, and reduce the rising segment. Therefore, by mixing the shallow energy level and the deep energy level, the lifespan of the device can be ensured, and the rising segment of the brightness of the device can be reduced, so that the device can quickly enter a stable state, which is beneficial to subsequent tests and applications. Comparing Examples 22, 24, and 25 in conjunction with Figure 21, it can be seen that from Examples 22 to 24 to 25, the doping ratio of deep-level materials increases, the lifetimes are all between 60-80h, and the difference in lifetimes is small.
  • the medium brightness rise time is about 7h, 5h, and 4h, respectively; compared with Example 21, Example 22, 24 or 25 has a higher proportion of deep-level materials, and the mobility of hole transport materials can be adjusted more widely and easier. Quantum dot devices with higher lifetime are obtained.
  • the absolute value of the top energy level of the valence band of the hole transport material should be less than or equal to 6.0eV, as shown in Examples 26-28 in Table 5 below (the hole injection layer adopts PEDOT:PSS (E HOMO : 5.1eV),
  • the electron transport layer uses ZnO):
  • the outer shell layer of the blue quantum dot material is ZnSe (the inner core is CdZnSe, the middle shell layer is ZnS, and the thickness of the outer shell layer is 2-5 nm, in order to construct a suitable ⁇ E EML-HTL energy level potential
  • the absolute value of the top energy level of the valence band of the hole transport material should be less than or equal to 5.4eV, as shown in Examples 29 to 31 in Table 6 below (the hole injection layer adopts PEDOT:PSS (E HOMO : 5.1eV), and the electron transport layer using ZnO):
  • the absolute value of the top energy level of the valence band of the hole transport material must be less than or equal to 5.9eV, as shown in Examples 32 to 35 in Table 7 below (the hole injection layer adopts PEDOT:PSS (E HOMO : 5.1eV),
  • the electron transport layer uses ZnO):
  • the outer shell of the blue quantum dot material is ZnSeS (the inner core is CdZnSe, the middle shell is ZnSe, and the outer shell thickness is 1.0-4.0 nm)
  • the absolute value of the top energy level of the valence band of the hole transport material must be less than or equal to 5.7eV, as shown in Examples 36 to 38 in Table 8 below (the hole injection layer adopts PEDOT:PSS (E HOMO : 5.1eV),
  • the electron transport layer uses ZnO):
  • red quantum dots whose outer shells are ZnS are used.
  • red quantum dots with ZnS outer shell inner core of CdZnSe, middle shell of ZnSe, valence band top energy level of 6.5 eV were used, and ZnO was used as the electron transport layer.
  • ZnS outer shell inner core of CdZnSe, middle shell of ZnSe, valence band top energy level of 6.5 eV
  • the driving voltage of the device drops more obviously under the constant current operation for a long time, indicating that the HTL mobility is higher than 1x10 -3 cm 2 /Vs, and better performance can be achieved.
  • the effect of suppressing the voltage rise of the device is higher than 1x10 -3 cm 2 /Vs, and better performance can be achieved.
  • the damage of the hole injection material of MoO 3 is effectively suppressed, so that the voltage rise of the device in the working process is compared with that of the organic material.
  • the hole injection layer material device has a significant reduction, and the measured time of the device life has also been effectively improved.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Nanotechnology (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

Dispositif optoélectronique, comprenant une anode, une couche de transport de trous, une couche électroluminescente à points quantiques et une cathode empilées en séquence, la couche électroluminescente à points quantiques comprenant un matériau à points quantiques qui a une structure cœur-écorce, une couche d'enveloppe externe du matériau à points quantiques étant ZnSeS, et la mobilité d'un matériau de transport de trous dans la couche de transport de trous étant supérieure à 1 × 10-4 cm2/Vs. Dans le dispositif optoélectronique, une couche d'enveloppe externe d'un point quantique est constituée de ZnSeS, qui a une capacité de liaison modérée pour des excitons dans la structure cœur-écorce du point quantique. L'enveloppe externe a peu d'effet sur l'effet tunnel des supports. Afin de construire une barrière d'injection de trous de ΔEEML-HTL ≥ 0,5 eV, le niveau d'énergie supérieure de la bande de valence du matériau de transport de trous requis est relativement peu profond. Lorsque la mobilité des trous d'un matériau HTL est supérieure ou égale à 1 × 10-4 cm2/Vs, la barrière d'injection de trous peut être construite et l'efficacité de l'injection de transport de trous dans le matériau à points quantiques peut être assurée en même temps.
PCT/CN2021/142724 2020-12-31 2021-12-29 Dispositif optoélectronique WO2022143821A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202011637679.7 2020-12-31
CN202011637679.7A CN114695723A (zh) 2020-12-31 2020-12-31 光电器件

Publications (1)

Publication Number Publication Date
WO2022143821A1 true WO2022143821A1 (fr) 2022-07-07

Family

ID=82134783

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/142724 WO2022143821A1 (fr) 2020-12-31 2021-12-29 Dispositif optoélectronique

Country Status (2)

Country Link
CN (1) CN114695723A (fr)
WO (1) WO2022143821A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108963087A (zh) * 2017-11-29 2018-12-07 广东聚华印刷显示技术有限公司 量子点电致发光器件及显示器
CN109545996A (zh) * 2018-11-28 2019-03-29 河南大学 一种量子点发光二极管及制备方法
CN109791996A (zh) * 2016-12-08 2019-05-21 广州华睿光电材料有限公司 高聚物及电致发光器件
CN110246973A (zh) * 2018-03-09 2019-09-17 三星电子株式会社 量子点器件和电子设备
US20200111933A1 (en) * 2018-10-05 2020-04-09 Samsung Electronics Co., Ltd. Light emitting device and display device including the same
CN111435710A (zh) * 2019-01-15 2020-07-21 三星电子株式会社 量子点器件和电子设备

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109791996A (zh) * 2016-12-08 2019-05-21 广州华睿光电材料有限公司 高聚物及电致发光器件
CN108963087A (zh) * 2017-11-29 2018-12-07 广东聚华印刷显示技术有限公司 量子点电致发光器件及显示器
CN110246973A (zh) * 2018-03-09 2019-09-17 三星电子株式会社 量子点器件和电子设备
US20200111933A1 (en) * 2018-10-05 2020-04-09 Samsung Electronics Co., Ltd. Light emitting device and display device including the same
CN109545996A (zh) * 2018-11-28 2019-03-29 河南大学 一种量子点发光二极管及制备方法
CN111435710A (zh) * 2019-01-15 2020-07-21 三星电子株式会社 量子点器件和电子设备

Also Published As

Publication number Publication date
CN114695723A (zh) 2022-07-01

Similar Documents

Publication Publication Date Title
CN103904178A (zh) 量子点发光器件
WO2020134147A1 (fr) Diode électroluminescente à points quantiques
WO2022143822A1 (fr) Dispositif photoélectrique
WO2020134161A1 (fr) Diode électroluminescente à points quantiques et son procédé de préparation
WO2022143821A1 (fr) Dispositif optoélectronique
WO2022143824A1 (fr) Dispositif optoélectronique
WO2022143823A1 (fr) Dispositif photoélectrique
WO2022143827A1 (fr) Dispositif photoélectrique
WO2022143825A1 (fr) Dispositif photoélectrique
WO2022143829A1 (fr) Dispositif photoélectrique
WO2022143831A1 (fr) Dispositif optoélectronique
WO2022143826A1 (fr) Dispositif photoélectrique
WO2022143828A1 (fr) Dispositif photoélectrique
WO2022143830A1 (fr) Dispositif photoélectrique
WO2022143832A1 (fr) Dispositif optoélectronique
WO2022143960A1 (fr) Dispositif photoélectrique
WO2022143566A1 (fr) Dispositif électroluminescent et son procédé de fabrication
CN114039002B (zh) 电子传输墨水、电子传输薄膜、电致发光二极管及显示器件
WO2022143567A1 (fr) Dispositif photoélectrique
WO2022143556A1 (fr) Dispositif photoélectrique
WO2023193427A1 (fr) Dispositif électroluminescent et son procédé de préparation, et appareil d'affichage
WO2022143820A1 (fr) Dispositif électroluminescent et son procédé de préparation
Vasanthi et al. Metal oxide charge transport materials for light emitting diodes-An overview
WO2023056829A1 (fr) Couche électroluminescente à points quantiques, procédé de préparation de couche électroluminescente à points quantiques et dispositif à diodes électroluminescentes à points quantiques
WO2022242178A1 (fr) Matériau de transport d'électrons et son procédé de préparation, et procédé de fabrication pour un dispositif d'affichage

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21914553

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21914553

Country of ref document: EP

Kind code of ref document: A1