CN116854682A

CN116854682A - Compound containing five-membered heterocyclic structure, application, organic electroluminescent device and display device

Info

Publication number: CN116854682A
Application number: CN202310805258.8A
Authority: CN
Inventors: 梁丙炎; 王丹; 陈磊; 陈雪芹; 张东旭
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-10-10

Abstract

The present disclosure provides a compound containing a five-membered heterocyclic structure, application, organic electroluminescent device and method for producing the sameThe compound containing the five-membered heterocyclic ring structure comprises at least one structural general formula shown in a formula (I) and a formula (II), wherein the meanings of each group and substituent are the same as in the specification. The compound containing the five-membered heterocyclic structure provided by the embodiment of the disclosure has a lower refractive index, and can be used together with a material with a high refractive index as a light extraction material, so that the luminous efficiency of the device is improved; the compound containing the five-membered heterocyclic structure provided by the embodiment of the disclosure has good thermal stability, and the OLED device using the light extraction layer containing the compound containing the five-membered heterocyclic structure has more stable performance and longer service life.

Description

Compound containing five-membered heterocyclic structure, application, organic electroluminescent device and display device

Technical Field

The embodiments of the present disclosure relate to the field of display technology, and in particular, to a compound containing a five-membered heterocyclic ring structure, an application, an organic electroluminescent device, and a display device.

Background

In recent years, organic electroluminescent displays (Organic Light Emitting Diode, OLED) have received increased attention as a new type of flat panel display. The display device has the characteristics of active light emission, high light emission brightness, high resolution, wide viewing angle, high response speed, low energy consumption, flexibility and the like, and becomes a hot mainstream display product in the market at present. With the continuous development of products, the resolution of customers for the products is higher and the power consumption requirement value is lower. There is a need to develop devices that are efficient, low voltage, and long life.

The OLED includes an anode, a cathode, and a light emitting layer disposed between the anode and the cathode, and its light emitting principle is that holes and electrons are injected into the light emitting layer from the anode and the cathode, respectively, and when the electrons and holes meet in the light emitting layer, the electrons and holes are recombined to generate excitons (exiton), and the excitons emit light while being converted from an excited state to a ground state.

At present, the existing organic electroluminescent device has the problems of low luminous efficiency, short service life and the like.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The technical problem to be solved by the present disclosure is to provide a compound containing a five-membered heterocyclic ring structure, an application, an organic electroluminescent device and a display device, so as to solve the problem of unstable performance of the existing organic electroluminescent device.

In one aspect, the present disclosure provides a compound containing a five-membered heterocyclic structure, the compound containing a five-membered heterocyclic structure including at least one structural formula as shown in formula (i) and formula (ii):

wherein X is N or C (H); y is O or S;

l1, L2 and L3 are each independently any one of a single bond, silicon, phosphorus oxy, substituted or unsubstituted C1 to C30 alkylene, substituted or unsubstituted C2 to C30 alkenylene, substituted or unsubstituted C1 to C30 alkyleneoxy, substituted or unsubstituted C1 to C30 thioalkylene, substituted or unsubstituted C6 to C50 arylene or substituted or unsubstituted C2 to C50 heteroarylene, where the substituted C1 to C30 alkylene, substituted C2 to C30 alkenylene, substituted C1 to C30 alkyleneoxy, substituted C1 to C30 thioalkylene, substituted C6 to C50 arylene or substituted C2 to C50 heteroarylene includes one or more of the following groups: silicon, phosphorus oxide, C1 to C30 alkylene, C2 to C30 alkenylene, C1 to C30 alkyleneoxy, C1 to C30 thioalkylene, C6 to C50 arylene, or C2 to C50 heteroarylene;

R1, R2 and R3 are each independently any of hydrogen, halogen, nitro, nitrile, substituted or unsubstituted C1 to C30 alkyl, substituted or unsubstituted C2 to C30 alkenyl, substituted or unsubstituted C1 to C30 alkoxy, substituted or unsubstituted C1 to C30 thioether, substituted or unsubstituted C6 to C50 aryl or substituted or unsubstituted C2 to C50 heteroaryl; here, substituted C1 to C30 alkyl, substituted C2 to C30 alkenyl, substituted C1 to C30 alkoxy, substituted C1 to C30 thioether, substituted C6 to C50 aryl or substituted C2 to C50 heteroaryl in R1, R2 and R3 means substituted with one or more of the following groups: halogen, nitro, nitrile, alkyl of C1 to C30, alkenyl of C2 to C30, alkoxy of C1 to C30, thioether of C1 to C30, aryl of C6 to C50 or heteroaryl of C2 to C50.

In an exemplary embodiment, formula (I) includes at least one of the structures of formulas (I-1), (I-2), (I-3), and (I-4):

wherein R1, R2 and R3, and L1, L2 and L3 are as defined in formula (I).

In an exemplary embodiment, formula (II) includes at least one of the structures of the sub-formulae (II-1), (II-2), (II-3) and (II-4):

Wherein R1, R2 and R3, and L1, L2 and L3 are as defined in formula (II).

In an exemplary embodiment, -L1-R1, -L2-R2, and-L3-R3 include at least the structure of formula (III):

wherein X1, Y1, Z1 are each independently N, C (R11) or C (H);

r4, R5 and R11 are each independently any of hydrogen, halogen, nitro, nitrile, substituted or unsubstituted C1 to C30 alkyl, substituted or unsubstituted C2 to C30 alkenyl, substituted or unsubstituted C1 to C30 alkoxy, substituted or unsubstituted C1 to C30 thioether, substituted or unsubstituted C6 to C50 aryl or substituted or unsubstituted C2 to C50 heteroaryl; here, substituted C1 to C30 alkyl, substituted C2 to C30 alkenyl, substituted C1 to C30 alkoxy, substituted C1 to C30 thioether, substituted C6 to C50 aryl or substituted C2 to C50 heteroaryl in R4, R5 and R11 means substituted with one or more of the following groups: halogen, nitro, nitrile, alkyl of C1 to C30, alkenyl of C2 to C30, alkoxy of C1 to C30, thioether of C1 to C30, aryl of C6 to C50 or heteroaryl of C2 to C50.

In an exemplary embodiment, -L1-R1, -L2-R2, and-L3-R3 comprise at least one structure according to formula (IV) and formula (V):

Wherein X2, Y2, Z2 are each independently N or C (H);

r6, R7, R8, R9 and R10 are each independently any of hydrogen, halogen, nitro, nitrile, substituted or unsubstituted C1 to C30 alkyl, substituted or unsubstituted C2 to C30 alkenyl, substituted or unsubstituted C1 to C30 alkoxy, substituted or unsubstituted C1 to C30 thioether, substituted or unsubstituted C6 to C50 aryl or substituted or unsubstituted C2 to C50 heteroaryl; here, the substituted C1 to C30 alkyl group, substituted C2 to C30 alkenyl group, substituted C1 to C30 alkoxy group, substituted C1 to C30 thioether group, substituted C6 to C50 aryl group or substituted C2 to C50 heteroaryl group in R6, R7, R8, R9 and R10 means substituted with one or more of the following groups: halogen, nitro, nitrile, alkyl of C1 to C30, alkenyl of C2 to C30, alkoxy of C1 to C30, thioether of C1 to C30, aryl of C6 to C50 or heteroaryl of C2 to C50.

In an exemplary embodiment, the compound containing a five-membered heterocyclic structure includes any one of the following compounds:

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in an exemplary embodiment, the five membered heterocyclic structure containing compound has a refractive index of 1.499 to 1.727 in the wavelength range of 450nm to 480 nm.

In an exemplary embodiment, the conversion temperature of the compound having a five membered heterocyclic structure is 89 ℃ to 167 ℃.

In a second aspect, the present disclosure also provides the use of the compound containing a five-membered heterocyclic structure as an electroluminescent organic material in an electronic device.

In an exemplary embodiment, the electroluminescent organic material is a light extraction layer material.

In a third aspect, the present disclosure further provides an organic electroluminescent device, including an anode, a light emitting layer, a cathode, and a light extraction layer stacked between the anode and the cathode, the light extraction layer being disposed on a side of the cathode away from the anode, the light extraction layer including a first light extraction sub-layer and a second light extraction sub-layer stacked, the second light extraction sub-layer having a refractive index smaller than that of the first light extraction sub-layer; wherein the material of the second light extraction sub-layer comprises a compound containing a five-membered heterocyclic ring structure as described above.

In a fourth aspect, the present disclosure also provides a display apparatus including the organic electroluminescent device as described above.

The present disclosure provides a compound containing a five-membered heterocyclic structure, an application, an organic electroluminescent device, and a display device, in which the molecular volume can be increased by increasing the molecular volume while maintaining the polarization rate of organic molecules unchanged or increased to some extent, and the increase of the molecular volume is greater than the increase of the molecular polarization rate, thereby effectively reducing the refractive index of the compound; the compound containing the five-membered heterocyclic structure is used as the material of the second light extraction sub-layer with the low refractive index to cover the second light extraction sub-layer with the high refractive index, so that the overall light extraction effect of the light extraction layer is improved, the performance stability of the organic electroluminescent device is effectively improved, the service life of the organic electroluminescent device is prolonged, and the display quality are improved.

Other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosed embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain, without limitation, the disclosed embodiments. The shapes and sizes of various components in the drawings are not to scale true, and are intended to be illustrative of the present disclosure.

FIG. 1 is a schematic diagram of an OLED display device;

FIG. 2 is a schematic plan view of a display substrate;

FIG. 3 is a schematic cross-sectional view of a display substrate;

fig. 4 is an equivalent circuit diagram of a pixel driving circuit;

fig. 5 is a schematic structural view of an organic electroluminescent device according to an exemplary embodiment of the present disclosure;

fig. 6 is a schematic structural view of another organic electroluminescent device according to an exemplary embodiment of the present disclosure;

fig. 7 is a schematic view of a display substrate structure according to an exemplary embodiment of the present disclosure.

Reference numerals illustrate:

10-anode; 20-a hole injection layer; 30—a hole transport layer;

40—an electron blocking layer; 50-a light emitting layer; 60-a hole blocking layer;

70—an electron transport layer; 80-an electron injection layer; 90-cathode;

101-a substrate; 102-a driving circuit layer; 103-a light emitting structure layer;

104, an encapsulation layer; 100—a light extraction layer; 210-a drive transistor;

211—a storage capacitor; 301-anode; 302—a pixel definition layer;

303—an organic light emitting layer; 304-cathode; 401—a first encapsulation layer;

402-a second encapsulation layer; 403-a third encapsulation layer; 110-a first light extraction sub-layer;

120-a second light extraction sub-layer.

Detailed Description

The embodiments herein may be embodied in a number of different forms. One of ordinary skill in the art will readily recognize the fact that the implementations and content may be transformed into a wide variety of forms without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure should not be construed as being limited to the following description of the embodiments. Embodiments of the present disclosure and features of embodiments may be combined with each other arbitrarily without conflict.

In the drawings, the size of constituent elements, thicknesses of layers, or regions may be exaggerated for clarity in some cases. Thus, any one implementation of the present disclosure is not necessarily limited to the dimensions shown in the figures, where the shapes and sizes of the components do not reflect true proportions. Further, the drawings schematically illustrate ideal examples, and any one implementation of the present disclosure is not limited to the shapes or the numerical values and the like shown in the drawings.

The ordinal numbers of "first", "second", "third", etc. in this document are provided to avoid intermixing of constituent elements and are not intended to be limiting in terms of number.

In this document, for convenience, terms such as "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like are used to describe the positional relationship of the constituent elements with reference to the accompanying drawings, only for convenience of description and simplicity of description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present disclosure. The positional relationship of the constituent elements may be appropriately changed according to the direction of the described constituent elements. Therefore, the present invention is not limited to the words described herein, and may be replaced as appropriate according to circumstances.

In this document, the terms "mounted," "connected," and "connected" are to be construed broadly, unless otherwise specifically indicated and defined. For example, it may be a fixed connection, a removable connection, or an integral connection; may be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intermediate members, or may be in communication with the interior of two elements. The meaning of the above terms in the present disclosure can be understood by one of ordinary skill in the art as appropriate.

Herein, a transistor refers to an element including at least three terminals of a gate electrode, a drain electrode, and a source electrode. The transistor has a channel region between a drain electrode (or a drain electrode terminal, a drain region, or a drain electrode) and a source electrode (or a source electrode terminal, a source region, or a source electrode), and a current can flow through the drain electrode, the channel region, and the source electrode. Herein, a channel region refers to a region through which current mainly flows.

Herein, the first electrode may be a drain electrode, the second electrode may be a source electrode, or the first electrode may be a source electrode, and the second electrode may be a drain electrode. In the case of using transistors having opposite polarities or in the case of a change in the direction of current during circuit operation, the functions of the "source electrode" and the "drain electrode" may be exchanged with each other. Thus, herein, the "source electrode" and the "drain electrode" may be interchanged.

In this context, "electrically connected" includes the case where constituent elements are connected together by an element having some electric action. The "element having a certain electric action" is not particularly limited as long as it can transmit and receive an electric signal between the constituent elements connected. The "element having some kind of electrical action" may be, for example, an electrode or a wiring, or a switching element such as a transistor, or other functional element such as a resistor, an inductor, or a capacitor.

As used herein, "parallel" refers to a state in which two straight lines form an angle of-10 ° or more and 10 ° or less, and thus, a state in which the angle is-5 ° or more and 5 ° or less is also included. The term "perpendicular" refers to a state in which the angle formed by two straight lines is 80 ° or more and 100 ° or less, and thus includes a state in which the angle is 85 ° or more and 95 ° or less.

In this context, "film" and "layer" may be interchanged. For example, the "conductive layer" may be sometimes replaced with a "conductive film". In the same manner, the "insulating film" may be replaced with the "insulating layer" in some cases.

By "about" herein is meant not strictly limited to numerical values which are within the limits of permitted process and measurement errors.

Fig. 1 is a schematic structural diagram of a display device. As shown in fig. 1, the OLED display device may include a timing controller, a data signal driver, a scan signal driver, a light emitting signal driver, and a pixel array, which may include a plurality of scan signal lines (S1 to Sm), a plurality of data signal lines (D1 to Dn), a plurality of light emitting signal lines (E1 to Eo), and a plurality of subpixels Pxij. In an exemplary embodiment, the timing controller may supply a gray value and a control signal suitable for a specification of the data signal driver to the data signal driver, may supply a clock signal, a scan start signal, etc. suitable for a specification of the scan signal driver to the scan signal driver, and may supply a clock signal, an emission stop signal, etc. suitable for a specification of the light emitting signal driver to the light emitting signal driver. The data signal driver may generate data voltages to be supplied to the data signal lines D1, D2, D3, … …, and Dn using the gray values and the control signals received from the timing controller. For example, the data signal driver may sample the gray value with a clock signal, and apply the data voltage corresponding to the gray value to the data signal lines D1 to Dn in pixel row units, n may be a natural number. The scan signal driver may generate scan signals to be supplied to the scan signal lines S1, S2, S3, … …, and Sm by receiving a clock signal, a scan start signal, and the like from the timing controller. For example, the scan signal driver may sequentially supply scan signals having on-level pulses to the scan signal lines S1 to Sm. For example, the scan signal driver may be configured in the form of a shift register, and may generate the scan signal in such a manner that the scan start signal supplied in the form of an on-level pulse is sequentially transmitted to the next stage circuit under the control of the clock signal, and m may be a natural number. The light emitting signal driver may generate the emission signals to be supplied to the light emitting signal lines E1, E2, E3, … …, and Eo by receiving a clock signal, an emission stop signal, and the like from the timing controller. For example, the light emission signal driver may sequentially supply the emission signal having the off-level pulse to the light emission signal lines E1 to Eo. For example, the light emission signal driver may be configured in the form of a shift register, and may generate the light emission signal in such a manner that the light emission stop signal supplied in the form of a cut-off level pulse is sequentially transmitted to the next stage circuit under the control of the clock signal, o may be a natural number. The pixel array may include a plurality of sub-pixels Pxij. Each subpixel Pxij may be connected to a corresponding data signal line, a corresponding scan signal line, and a corresponding light emitting signal line, and i and j may be natural numbers. The subpixel Pxij may refer to a subpixel in which a transistor is connected to the ith scan signal line and to the jth data signal line. In an exemplary embodiment, the pixel array may be disposed on the display substrate.

Fig. 2 is a schematic plan view of a display substrate. As shown in fig. 2, the display substrate may include a plurality of pixel units P arranged in a matrix, at least one of the plurality of pixel units P includes a first subpixel P1 emitting light of a first color, a second subpixel P2 emitting light of a second color, and a third subpixel P3 emitting light of a third color, and each of the first subpixel P1, the second subpixel P2, and the third subpixel P3 includes a pixel driving circuit and a light emitting device. The pixel driving circuits in the first, second and third sub-pixels P1, P2 and P3 are respectively connected to the scan signal line, the data signal line and the light emitting signal line, and the pixel driving circuits are configured to receive the data voltage transmitted by the data signal line and output a corresponding current to the light emitting device under the control of the scan signal line and the light emitting signal line. The light emitting devices in the first, second and third sub-pixels P1, P2 and P3 are respectively connected to the pixel driving circuits of the sub-pixels, and the light emitting devices are configured to emit light of corresponding brightness in response to the current output from the pixel driving circuits of the sub-pixels.

In an exemplary embodiment, the pixel unit P may include red (R), green (G) and blue (B) sub-pixels therein, or may include red, green, blue and white sub-pixels therein, which are not limited herein. In an exemplary embodiment, the shape of the sub-pixels in the pixel unit may be rectangular, diamond, pentagonal, or hexagonal. When the pixel unit includes three sub-pixels, the three sub-pixels may be arranged in a horizontal parallel, vertical parallel or delta manner, and when the pixel unit includes four sub-pixels, the four sub-pixels may be arranged in a horizontal parallel, vertical parallel or Square (Square) manner, which is not limited herein.

Fig. 3 is a schematic cross-sectional structure of a display substrate, illustrating the structure of three sub-pixels of an OLED display substrate. As shown in fig. 3, the display substrate may include a driving circuit layer 102 disposed on a base 101, a light emitting structure layer 103 disposed on a side of the driving circuit layer 102 away from the base 101, and an encapsulation layer 104 disposed on a side of the light emitting structure layer 103 away from the base 101, in a plane perpendicular to the display substrate. In some possible implementations, the display substrate may include other layers, such as spacer posts, etc., which are not limited herein.

In an exemplary embodiment, the substrate may be a flexible substrate, or may be a rigid substrate. The flexible substrate may include a first flexible material layer, a first inorganic material layer, a semiconductor layer, a second flexible material layer, and a second inorganic material layer stacked, the materials of the first flexible material layer and the second flexible material layer may be Polyimide (PI), polyethylene terephthalate (PET), or a surface-treated polymer film, the materials of the first inorganic material layer and the second inorganic material layer may be silicon nitride (SiNx) or silicon Oxide (SiOx), etc., for improving the water-oxygen resistance of the substrate, and the materials of the semiconductor layer may be amorphous silicon (a-si), polysilicon (p-si), or Oxide (Oxide).

In an exemplary embodiment, the driving circuit layer 102 of each sub-pixel may include a plurality of transistors and storage capacitors constituting a pixel driving circuit, which is illustrated by way of example only with one driving transistor and one storage capacitor. In some possible implementations, the driving circuit layer 102 of each subpixel may include: a first insulating layer disposed on the substrate; an active layer disposed on the first insulating layer; a second insulating layer covering the active layer; a gate electrode and a first capacitor electrode disposed on the second insulating layer; a third insulating layer covering the gate electrode and the first capacitor electrode; a second capacitor electrode disposed on the third insulating layer; a fourth insulating layer covering the second capacitor electrode, wherein a via hole is formed in the second insulating layer, the third insulating layer and the fourth insulating layer, and the via hole exposes the active layer; the source electrode and the drain electrode are arranged on the fourth insulating layer and are respectively connected with the active layer through the via hole; and a flat layer covering the structure, wherein the flat layer is provided with a via hole, and the via hole exposes the drain electrode. The active layer, the gate electrode, the source electrode, and the drain electrode constitute a transistor 210, and the first capacitor electrode and the second capacitor electrode constitute a storage capacitor 211.

In an exemplary embodiment, the light emitting structure layer 103 includes a light emitting device that emits light of an organic material under an electric field, and the light emitting structure layer 103 may include an anode 301, a pixel defining layer 302, an organic light emitting layer 303, and a cathode 304. The anode 301 is disposed on the planarization layer and connected to the drain electrode of the driving transistor 210 through a via hole formed in the planarization layer; the pixel defining layer 302 is disposed on the anode 301 and the flat layer, and pixel openings are disposed on the pixel defining layer 302, and the anode 301 is exposed by the pixel openings; the organic light emitting layer 303 is at least partially disposed within the pixel opening, the organic light emitting layer 303 being connected to the anode 301; a cathode 304 is provided on the organic light emitting layer 303, the cathode 304 being connected to the organic light emitting layer 303; the organic light emitting layer 303 emits light of a corresponding color under the driving of the anode 301 and the cathode 304.

In an exemplary embodiment, the encapsulation layer 104 may include a first encapsulation layer 401, a second encapsulation layer 402, and a third encapsulation layer 403 stacked, the first encapsulation layer 401 and the third encapsulation layer 403 may be made of an inorganic material, the second encapsulation layer 402 may be made of an organic material, and the second encapsulation layer 402 is disposed between the first encapsulation layer 401 and the third encapsulation layer 403, so that external moisture may not enter the light emitting structure layer 103.

In an exemplary embodiment, the organic light Emitting Layer of the OLED light Emitting device may include an emission Layer (EML) and any one or more of the following: a Hole injection Layer (Hole Injection Layer, HIL), a Hole transport Layer (Hole Transport Layer, HTL), a Hole Blocking Layer (HBL), an electron blocking Layer (Electron Block Layer, EBL), an electron injection Layer (Electron Injection Layer, EIL), and an electron transport Layer (Electron Transport Layer, ETL). The organic material emits light as needed by utilizing the light emission characteristics of the organic material under the voltage drive of the anode and the cathode.

In an exemplary embodiment, the light emitting layers of the OLED light emitting devices of different colors are different. For example, the red light emitting device includes a red light emitting layer, the green light emitting device includes a green light emitting layer, and the blue light emitting device includes a blue light emitting layer. In order to reduce the process difficulty and improve the yield, a common layer may be used for the hole injection layer and the hole transport layer on one side of the light emitting layer, and a common layer may be used for the electron injection layer and the electron transport layer on the other side of the light emitting layer. In an exemplary embodiment, any one or more of the hole injection layer, the hole transport layer, the electron injection layer, and the electron transport layer may be manufactured by one process (one evaporation process or one inkjet printing process), but isolation is achieved by a surface level difference of the formed film layer or by surface treatment or the like. For example, any one or more of the hole injection layer, the hole transport layer, the electron injection layer, and the electron transport layer corresponding to adjacent sub-pixels may be isolated. In an exemplary embodiment, the organic light emitting layer may be formed through an evaporation process or an inkjet process.

In an exemplary embodiment, the pixel driving circuit may be a 3T1C, 4T1C, 5T2C, 6T1C, or 7T1C structure. Fig. 4 is an equivalent circuit schematic diagram of a pixel driving circuit. As shown in fig. 4, the pixel driving circuit may include 7 transistors (first transistor T1 to seventh transistor T7) and 1 storage capacitor C, and is connected to 6 signal lines (data signal line D, first scan signal line S1, second scan signal line S2, light emitting signal line E, initial signal line INIT, and first power supply line VDD).

In an exemplary embodiment, a first terminal of the storage capacitor C is connected to the first power line VDD, and a second terminal of the storage capacitor C is connected to the second node N2, i.e., a second terminal of the storage capacitor C is connected to the control electrode of the third transistor T3.

The control electrode of the first transistor T1 is connected to the second scan signal line S2, the first electrode of the first transistor T1 is connected to the initial signal line INIT, and the second electrode of the first transistor is connected to the second node N2. When the turn-on level scan signal is applied to the second scan signal line S2, the first transistor T1 transmits an initialization voltage to the control electrode of the third transistor T3 to initialize the charge amount of the control electrode of the third transistor T3.

The control electrode of the second transistor T2 is connected to the first scanning signal line S1, the first electrode of the second transistor T2 is connected to the second node N2, and the second electrode of the second transistor T2 is connected to the third node N3. When the on-level scan signal is applied to the first scan signal line S1, the second transistor T2 connects the control electrode of the third transistor T3 with the second electrode.

The control electrode of the third transistor T3 is connected to the second node N2, i.e., the control electrode of the third transistor T3 is connected to the second end of the storage capacitor C, the first electrode of the third transistor T3 is connected to the first node N1, and the second electrode of the third transistor T3 is connected to the third node N3. The third transistor T3 may be referred to as a driving transistor, and the third transistor T3 determines an amount of driving current flowing between the first power line VDD and the second power line VSS according to a potential difference between a control electrode and the first electrode thereof.

The control electrode of the fourth transistor T4 is connected to the first scan signal line S1, the first electrode of the fourth transistor T4 is connected to the data signal line D, and the second electrode of the fourth transistor T4 is connected to the first node N1. The fourth transistor T4 may be referred to as a switching transistor, a scanning transistor, or the like, and when an on-level scanning signal is applied to the first scanning signal line S1, the fourth transistor T4 causes the data voltage of the data signal line D to be input to the pixel driving circuit.

The control electrode of the fifth transistor T5 is connected to the light emitting signal line E, the first electrode of the fifth transistor T5 is connected to the first power line VDD, and the second electrode of the fifth transistor T5 is connected to the first node N1. The control electrode of the sixth transistor T6 is connected to the light emitting signal line E, the first electrode of the sixth transistor T6 is connected to the third node N3, and the second electrode of the sixth transistor T6 is connected to the first electrode of the light emitting device. The fifth transistor T5 and the sixth transistor T6 may be referred to as light emitting transistors. When the on-level light emitting signal is applied to the light emitting signal line E, the fifth transistor T5 and the sixth transistor T6 emit light by forming a driving current path between the first power line VDD and the second power line VSS.

The control electrode of the seventh transistor T7 is connected to the first scan signal line S1, the first electrode of the seventh transistor T7 is connected to the initial signal line INIT, and the second electrode of the seventh transistor T7 is connected to the first electrode of the light emitting device. When the on-level scanning signal is applied to the first scanning signal line S1, the seventh transistor T7 transmits an initialization voltage to the first electrode of the light emitting device to initialize or release the amount of charge accumulated in the first electrode of the light emitting device.

In an exemplary embodiment, the second electrode of the light emitting device is connected to the second power line VSS, the signal of the second power line VSS is a low level signal, and the signal of the first power line VDD is a continuously supplied high level signal. The first scanning signal line S1 is a scanning signal line in the pixel driving circuit of the display line, the second scanning signal line S2 is a scanning signal line in the pixel driving circuit of the previous display line, that is, for the nth display line, the first scanning signal line S1 is S (n), the second scanning signal line S2 is S (n-1), the second scanning signal line S2 of the display line and the first scanning signal line S1 in the pixel driving circuit of the previous display line are the same signal line, so that signal lines of the display panel can be reduced, and a narrow frame of the display panel can be realized.

In an exemplary embodiment, the first to seventh transistors T1 to T7 may be P-type transistors or may be N-type transistors. The same type of transistor is adopted in the pixel driving circuit, so that the process flow can be simplified, the process difficulty of the display panel is reduced, and the yield of products is improved. In some possible implementations, the first to seventh transistors T1 to T7 may include a P-type transistor and an N-type transistor.

In the exemplary embodiment, the first scan signal line S1, the second scan signal line S2, the light emitting signal line E, and the initial signal line INIT extend in a horizontal direction, and the second power line VSS, the first power line VDD, and the data signal line D extend in a vertical direction.

In an exemplary embodiment, the light emitting device may be an Organic Light Emitting Diode (OLED) including a first electrode (anode), an organic light emitting layer, and a second electrode (cathode) stacked.

In an exemplary embodiment, taking an example that 7 transistors in the pixel driving circuit shown in fig. 4 are P-type transistors, the operation of the pixel driving circuit may include:

the first phase A1, referred to as a reset phase, signals of the second scanning signal line S2 are low-level signals, and signals of the first scanning signal line S1 and the light-emitting signal line E are high-level signals. The signal of the second scanning signal line S2 is a low level signal, so that the first transistor T1 is turned on, the signal of the initial signal line INIT is provided to the second node N2, the storage capacitor C is initialized, and the original data voltage in the storage capacitor is cleared. The signals of the first scan signal line S1 and the light emitting signal line E are high level signals, so that the second transistor T2, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6 and the seventh transistor T7 are turned off, and the OLED does not emit light at this stage.

The second phase A2, called a data writing phase or a threshold compensation phase, the signal of the first scanning signal line S1 is a low level signal, the signals of the second scanning signal line S2 and the light emitting signal line E are high level signals, and the data signal line D outputs a data voltage. At this stage, since the second terminal of the storage capacitor C is at a low level, the third transistor T3 is turned on. The signal of the first scan signal line S1 is a low level signal to turn on the second transistor T2, the fourth transistor T4, and the seventh transistor T7. The second transistor T2 and the fourth transistor T4 are turned on such that the data voltage outputted from the data signal line D is supplied to the second node N2 through the first node N1, the turned-on third transistor T3, the third node N3, and the turned-on second transistor T2, and a difference between the data voltage outputted from the data signal line D and the threshold voltage of the third transistor T3 is charged into the storage capacitor C, the voltage of the second terminal (second node N2) of the storage capacitor C is vd—vth|, vd is the data voltage outputted from the data signal line D, and Vth is the threshold voltage of the third transistor T3. The seventh transistor T7 is turned on to supply the initial voltage of the initial signal line INIT to the first electrode of the OLED, initialize (reset) the first electrode of the OLED, empty the pre-stored voltage therein, complete the initialization, and ensure that the OLED does not emit light. The signal of the second scanning signal line S2 is a high level signal, and turns off the first transistor T1. The signal of the light-emitting signal line E is a high level signal, and turns off the fifth transistor T5 and the sixth transistor T6.

The third stage A3 is referred to as a light-emitting stage, in which the signal of the light-emitting signal line E is a low-level signal, and the signals of the first scanning signal line S1 and the second scanning signal line S2 are high-level signals. The signal of the light emitting signal line E is a low level signal, so that the fifth transistor T5 and the sixth transistor T6 are turned on, and the power supply voltage outputted from the first power supply line VDD supplies a driving voltage to the first electrode of the OLED through the turned-on fifth transistor T5, third transistor T3 and sixth transistor T6, thereby driving the OLED to emit light.

During driving of the pixel driving circuit, the driving current flowing through the third transistor T3 (driving transistor) is determined by the voltage difference between the gate electrode and the first electrode thereof. Since the voltage of the second node N2 is Vdata- |vth|, the driving current of the third transistor T3 is:

I＝K*(Vgs-Vth) ² ＝K*[(Vdd-Vd+|Vth|)-Vth] ² ＝K*[(Vdd-Vd] ²

where I is a driving current flowing through the third transistor T3, that is, a driving current for driving the OLED, K is a constant, vgs is a voltage difference between the gate electrode and the first electrode of the third transistor T3, vth is a threshold voltage of the third transistor T3, vd is a data voltage output from the data signal line D, and Vdd is a power supply voltage output from the first power supply line Vdd.

The current top-emitting OLED device adopts a total reflection anode and a semitransparent cathode to enhance the light-emitting efficiency through microcavity effect. Light extraction layers are often incorporated into OLED device structures, and the light extraction layers typically employ high refractive index materials to reduce total reflection at the interface.

Fig. 5 is a schematic structural view of an organic electroluminescent device according to an exemplary embodiment of the present disclosure. As shown in fig. 5, the organic electroluminescent device may include an anode 10, a light emitting layer 50, a cathode 90, and a light extraction layer 100 stacked, the light emitting layer 50 being disposed between the anode 10 and the cathode 90, the light extraction layer 100 being disposed at a side of the cathode 90 remote from the anode 10. In an exemplary embodiment, the light emitting layer 50 emits light under the action of the anode 10 and the cathode 90, and the light extraction layer 100 is configured to improve the light emitting efficiency.

In an exemplary embodiment, when light waves (electromagnetic waves) are incident on the interface between the metal and the dielectric medium, free electrons on the metal surface are subjected to collective oscillation, near-field electromagnetic waves which are formed by coupling the free electrons on the electromagnetic waves and propagate along the metal surface, resonance is generated if the oscillation frequency of the electrons is consistent with the frequency of the incident light waves, and the energy of the electromagnetic field is effectively converted into collective vibration energy of the free electrons on the metal surface in the resonance state, so that a special electromagnetic mode is formed: the electromagnetic field is confined to a small area of the metal surface and is enhanced, which is called a surface plasmon (Surface Plasmon Polariton, SPP) effect, which causes a decrease in the efficiency of outgoing light. According to the embodiment of the disclosure, the light extraction layer is arranged on the cathode, so that the SPP effect can be effectively eliminated, and the emergent light efficiency is improved. For the top emission type OLED, the cathode has semi-transparent and semi-reflective effects on emergent light, and the reflectivity and the transmissivity of the emergent light can be effectively adjusted by arranging the light extraction layer on the cathode, the cavity length of the optical micro-resonant cavity can be effectively adjusted, and the emergent light intensity is improved. The high refractive index and low refractive index materials can be simultaneously adopted in the light extraction layer, so that the refractive index matched with air is maximized, destructive interference of reflection is promoted, optical loss at an interface is reduced, the overall reflection of the light extraction layer is reduced, and therefore the luminous efficiency and the service life of the OLED device are improved.

In an exemplary embodiment, the light extraction layer 100 may include a first light extraction sub-layer 110 and a second light extraction sub-layer 120 stacked, wherein the first light extraction sub-layer 110 has a high refractive index, i.e., as a high refractive index layer, and the second light extraction sub-layer 120 has a low refractive index, i.e., as a low refractive index layer. The first light extraction sub-layer may have a higher refractive index than the second light extraction sub-layer, and in an exemplary embodiment, the first light extraction sub-layer, which is a high refractive index layer, may have a refractive index of 1.90 to 2.38, and the second light extraction sub-layer, which is a low refractive index layer, may have a refractive index of 1.39 to 1.80. In the flexible display package, in order to increase the microcavity effect, the light extraction layer 100 is formed by matching materials with high refractive index and low refractive index so as to change the optical path and the propagation direction, and the diffuse reflection phenomenon is similar to the formation of the diffuse reflection phenomenon, the color polarization optical limitation caused by the microcavity effect is broken through, the interface light extraction total reflection is further improved, and the microcavity effect of light is increased, so that the light coupling efficiency of the whole device is improved, the light extraction mode is improved, the light which is originally limited in the device can be extracted, and the higher light extraction efficiency is shown.

The current development of light extraction layer materials has focused more on high refractive index materials, less research and application for low refractive index materials, and more on the use of inorganic low refractive index materials, such as lithium fluoride (LiF). According to the research of the inventor, the inorganic low refractive index material has stronger water absorption and often leads to unstable performance of the organic electroluminescent device; inorganic low refractive index materials also have the defect of poor stress resistance and are one of factors causing the weakness of the organic electroluminescent device.

In an exemplary embodiment, the disclosed embodiments provide a compound containing a five-membered heterocyclic structure, including at least one structural formula as shown in formula (i) and formula (ii):

wherein X is N or C (H); y is O or S;

In the embodiment of the disclosure, by attaching a linking group, such as silicon, phosphorus oxide or pyridine, to a compound having a structure of a five-membered ring containing a heteroatom as a core, the molecular volume can be increased while maintaining the polarization of the organic molecule unchanged or increased to some extent, and the increase of the molecular volume is larger than the increase of the molecular polarization, thereby effectively reducing the refractive index of the compound, so that the second light extraction sublayer using the compound having a five-membered heterocyclic structure as a material has a lower refractive index.

In an exemplary embodiment, the compound having a five membered heterocyclic structure of formula (I) includes at least one of the structures of formulas (I-1), (I-2), (I-3), and (I-4):

/>

wherein R1, R2 and R3, and L1, L2 and L3 are as defined in formula (I).

In an exemplary embodiment, the compound having a five membered heterocyclic structure of formula (II) includes at least one of the structures of formulas (II-1), (II-2), (II-3) and (II-4):

/>

wherein R1, R2 and R3, and L1, L2 and L3 are as defined in formula (II).

Wherein X1, Y1, Z1 are each independently N, C (R11) or C (H);

In an exemplary embodiment, in formula (iii), X1, Y1, Z1 are each independently N, C (R11) or C (H), and at least one is N.

Wherein X2, Y2, Z2 are each independently N or C (H);

In an exemplary embodiment, in formula (iv) and formula (v), X2, Y2, Z2 are each independently N or C (H), and at least one is N.

In embodiments of the present disclosure, the aryl group includes, but is not limited to, phenyl, naphthyl, anthracenyl, acenaphthylenyl, indenyl, phenanthrenyl, azulenyl, pyrenyl, fluorenyl, perylenyl, spirofluorenyl, spirobifluorenyl, yl, benzophenanthryl, benzanthrenyl, fluoranthenyl, picenyl, tetracenyl, and indenophenyl.

The term "hetero" as used in heteroaryl means that at least one carbon atom in the aromatic ring is substituted with a heteroatom selected from any one or more of nitrogen atom (N), oxygen atom (O) and sulfur atom (S).

The heteroaryl group includes, but is not limited to, benzoxazolyl, benzothiazolyl, indolyl, benzimidazolyl, pyrrolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetrazinyl, imidazolyl, pyrazolyl, carbazolyl, thienyl, thiazolyl, benzocarbazolyl, dibenzocarbazolyl, indolocarbazolyl, indenocarbazolyl, quinolinyl, isoquinolyl, phthalazinyl (phthalazinyl), quinoxalinyl (quinoxalinyl), cinnolinyl (cinnolinyl), quinazolinyl, phthalazinyl, benzoquinolinyl, benzoisoquinolinyl, benzoquinazolinyl, benzoquinoxalinyl, acridinyl, phenanthrolinyl, furanyl, pyranyl, oxazinyl, oxazolyl, oxadiazolyl (oxadizolyl), triazolyl, dioxinyl (dioxanyl), benzofuranyl, dibenzofuranyl, thiopyranyl, thiazinyl, benzothienyl, and N-substituted spirofluorenyl.

The present disclosure also provides an application of the compound containing a five-membered heterocyclic structure, which is used as an electroluminescent organic material in an electronic device.

In an exemplary embodiment, the present disclosure further provides an application of the compound containing a five-membered heterocyclic structure, where the electroluminescent organic material is a light extraction layer material.

In an exemplary embodiment, the present disclosure further provides an organic electroluminescent device including an anode, a light emitting layer, a cathode, and a light extraction layer stacked between the anode and the cathode, the light extraction layer being disposed on a side of the cathode away from the anode, the light extraction layer including a first light extraction sub-layer and a second light extraction sub-layer stacked, the second light extraction sub-layer having a refractive index smaller than that of the first light extraction sub-layer; wherein the material of the second light extraction sub-layer comprises the compound containing a five-membered heterocyclic ring structure.

The material of the second light extraction sublayer in the embodiment of the disclosure increases the molecular volume by adding groups such as silicon, phosphorus oxide or pyridyl, and simultaneously maintains the constant or certain increase of the polarization rate of the organic molecules, and the increase of the molecular volume is larger than the increase of the molecular polarization rate, so that the refractive index of the compound containing the five-membered heterocyclic structure is effectively reduced, and the second light extraction sublayer has a lower refractive index.

The structural optimization ensures that the material of the second light extraction sub-layer is used as an organic low refractive index material to replace an inorganic low refractive index material, can be matched with a high refractive index material to be applied to a covering layer, not only effectively improves the performance stability, the service life and the light extraction effect of the organic electroluminescent device and improves the quality of a display device, but also has the advantages of simple structure, easy synthesis, low cost and the like.

In an exemplary embodiment, the compound having a five-membered heterocyclic structure may be any one of the following compounds:

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in an exemplary embodiment, the refractive index of the compound containing the five membered heterocyclic structure is measured using an ellipsometer, which scans over a range of 245nm to 1000nm; the silicon wafer is used for evaporating the material film of the light extraction layer, and the thickness of the material film of the light extraction layer is 50nm. The refractive index test results are shown in table 1.

TABLE 1 refractive index of five membered heterocyclic Structure containing Compounds

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The refractive index of the compound LiF lithiated fluoride of comparative example 1 was 1.394 to 1.450 in the wavelength range of 450nm to 800 nm. In an exemplary embodiment, the refractive index of the five-membered heterocyclic structure-containing compound may be 1.499 to 1.727 in a wavelength range of 450nm to 480 nm. In an exemplary embodiment, the refractive index of the five-membered heterocyclic structure-containing compound may be 1.554 to 1.660 in a wavelength range of 450nm to 480 nm. The refractive index of the material of the second light extraction sub-layer may be lower than 1.80 in the wavelength range of 450nm to 480nm, and the compound containing the five-membered heterocyclic structure in the embodiments of the present disclosure may be provided as the material of the second light extraction sub-layer. The material of the first light extraction sub-layer may be a compound having a refractive index of 1.90 to 2.38 in the wavelength range of 450nm to 480 nm. In the flexible packaging display device, the compound with the low refractive index and the five-membered heterocyclic structure in the embodiment of the disclosure can be used as the organic material of the second light extraction sub-layer to replace inorganic lithiated fluorine, and the organic material can be covered on the first light extraction sub-layer with higher refractive index, so that the light coupling out of the device is facilitated, the efficiency of the device is improved, and meanwhile, the disadvantages of the inorganic low refractive index covering layer can be avoided.

Glass transition temperature of compound containing five membered heterocyclic ring structure the measuring instrument of glass transition temperature is DSC differential scanning calorimeter; the test atmosphere is nitrogen, the heating rate is 10 ℃/min, and the temperature range is 50 ℃ to 300 ℃; the glass transition temperatures (Tg) measured are shown in Table 2.

Table 2 glass transition temperature (Tg) of Compound containing five membered heterocyclic Structure

Compounds of formula (I)	Glass transition temperature (. Degree. C.)
		10	89℃
4	110℃
		18	167℃

The glass transition temperature (Tg) of the compound containing the five-membered heterocyclic structure determines the thermal stability of the material of the light extraction layer material in vapor deposition, and the higher the Tg, the better the thermal stability of the material, and the more stable and longer the service life of the OLED device using the light extraction layer containing the compound containing the five-membered heterocyclic structure.

In an exemplary embodiment, the glass transition temperature of the compound containing the five-membered heterocyclic structure is 89 ℃ to 167 ℃, and a higher glass transition temperature is favorable for material stability, so that the problem that impurities are generated in evaporation due to unstable light extraction materials to influence the service life of the organic electroluminescent device is avoided.

The five-membered heterocyclic structure-containing compounds of the examples of the present disclosure will be further described below with reference to specific structures and synthesis examples.

Example 1: synthesis of Compound 4

1. Preparation of intermediate C1

Under irradiation of visible light, under Ba (OH) ₂ And 95% EtOH in the presence of tetrakis (triphenylphosphine) palladium, 0.1mol of the first starting material A1 and 0.3mol of the second starting material B1 were added and reacted at 50 ℃; the reaction flask was immersed in a water bath using a 100W tungsten bulb as the irradiation source to prevent the photo-thermal effect. After the completion of the reaction, the reaction mixture was cooled to room temperature, and the filtrate was obtained by filtration through celite. Concentrating, heating, adding a small amount of ethanol, standing to room temperature for recrystallization, filtering and leaching with ethanol to obtain a recrystallized solid, thus obtaining a solid first intermediate C1.

2. Preparation of Compound 4

Under irradiation of visible light, under Ba (OH) ₂ And 95% EtOH in the presence of tetrakis (triphenylphosphine) palladium, 0.1mol of the first intermediate C1 was added to react with 0.3mol of the third starting material D1 at 50 ℃; using a 100W tungsten bulb as the irradiation source, the reaction flask was immersed in a water bath to prevent photothermalEffect. After the completion of the reaction, the reaction mixture was cooled to room temperature, and the filtrate was obtained by filtration through celite. Concentrating, heating, adding a small amount of ethanol, standing to room temperature for recrystallization, filtering and leaching with ethanol to obtain a recrystallized solid, thus obtaining the compound 4.

Structural characterization data for compound 4:

mass spectrum m/z:866.59, element content (%): c (C) ₆₀ H ₇₄ N ₄ O，C，83.09；H，8.6；N，6.46；O,1.84。

¹ H NMR(300MHz,DMSO-d ₆ )：8.12(6H),7.68(1H),7.61-7.62(2H),7.55(3H),7.3-7.38(2H),7.16-7.23(2H),6.99(1H),6.77(1H),5.87(1H),5.3(1H),1.32(54H)；

Example 2: synthesis of Compound 10

1. Preparation of intermediate C2

Under irradiation of visible light, under Ba (OH) ₂ And 95% EtOH in the presence of tetrakis (triphenylphosphine) palladium, 0.1mol of the first starting material A2 and 0.3mol of the second starting material B1 were added and reacted at 50 ℃; the reaction flask was immersed in a water bath using a 100W tungsten bulb as the irradiation source to prevent the photo-thermal effect. After the completion of the reaction, the reaction mixture was cooled to room temperature, and the filtrate was obtained by filtration through celite. Concentrating, heating, adding a small amount of ethanol, standing to room temperature for recrystallization, filtering and leaching with ethanol to obtain a recrystallized solid, thus obtaining a solid first intermediate C2.

2. Preparation of Compound 10

Under irradiation of visible light, under Ba (OH) ₂ And 95% EtOH in the presence of tetrakis (triphenylphosphine) palladium, 0.1mol of the first intermediate C2 was added to react with 0.3mol of the third starting material D1 at 50 ℃; use of a 100W tungsten bulb as illuminationA source, immersing the reaction flask in a water bath to prevent photo-thermal effects. After the completion of the reaction, the reaction mixture was cooled to room temperature, and the filtrate was obtained by filtration through celite. Concentrating, heating, adding a small amount of ethanol, standing to room temperature for recrystallization, filtering and leaching with ethanol to obtain a recrystallized solid, thus obtaining the compound 10.

Structural characterization data for compound 10:

mass spectrum m/z:864.57, element content (%): c (C) ₆₀ H ₇₂ N ₄ O，C，83.29；H，8.39；N，6.48；O,1.85。

¹ H NMR(300MHz,DMSO-d ₆ )：8.12(6H),8(1H),7.65(3H),7.6(2H),7.55(3H),7.24(3H),1.32(54H)。

Example 3: synthesis of Compound 22

Under irradiation of visible light, under Ba (OH) ₂ And 95% EtOH in the presence of tetrakis (triphenylphosphine) palladium, 0.1mol of fourth starting material E1 and 0.3mol of fifth starting material F1 were added and reacted at 80 ℃; the reaction flask was immersed in a water bath using a 100W tungsten bulb as the irradiation source to prevent the photo-thermal effect. After the completion of the reaction, the reaction mixture was cooled to room temperature, and the filtrate was obtained by filtration through celite. Concentrating, heating, adding a small amount of ethanol, standing to room temperature for recrystallization, filtering and leaching with ethanol to obtain a recrystallized solid, thus obtaining the compound 22.

Structural characterization data for compound 22:

mass spectrum m/z:653.03, element content (%): c (C) ₄₂ H ₆₀ N ₄ S，C，77.25；H，8.26；N，8.58；S,4.91。

¹ H NMR(300MHz,DMSO-d ₆ )：7.87(3H),7.51(3H),1.36(27H),1.32(27H)。

Example 4: synthesis of Compound 24

Under irradiation of visible light, under Ba (OH) ₂ And 95% EtOH in the presence of tetrakis (triphenylphosphine) palladium, 0.1mol of fourth starting material E2 and 0.3mol of fifth starting material F2 were added and reacted at 80 ℃; the reaction flask was immersed in a water bath using a 100W tungsten bulb as the irradiation source to prevent the photo-thermal effect. After the completion of the reaction, the reaction mixture was cooled to room temperature, and the filtrate was obtained by filtration through celite. Concentrating, heating, adding a small amount of ethanol, standing to room temperature for recrystallization, filtering and leaching with ethanol to obtain a recrystallized solid, thus obtaining the compound 24.

Structural characterization data for compound 24:

mass spectrum m/z:1028.23, element content (%): c (C) ₅₇ H ₇₂ N ₇ O ₃ P ₃ S，C，66.58；H，7.06；N，9.54；O,4.67；P,9.04；S,3.12。

¹ H NMR(300MHz,DMSO-d ₆ )：8.53(6H),7.82(6H),7.77(6H),1.35(54H)。

The compounds in this example can be synthesized in the manner described above with reference to compounds 4, 10, 22 and 24.

Fig. 6 is a schematic structural view of another organic electroluminescent device according to an exemplary embodiment of the present disclosure. As shown in fig. 6, the light emitting device may include an anode 10, a cathode 90, a light extraction layer 100, and an organic light emitting layer disposed between the anode 10 and the cathode 90, which are stacked. In an exemplary embodiment, the light extraction layer 100 may further provide a first light extraction sub-layer 110 and a second light extraction sub-layer 120. In an exemplary embodiment, the organic light emitting layer may include a hole injection layer 20, a hole transport layer 30, an electron blocking layer 40, a light emitting layer 50, a hole blocking layer 60, an electron transport layer 70, and an electron injection layer 80 stacked. The hole injection layer 20, the hole transport layer 30, and the electron blocking layer 40 are disposed between the anode 10 and the light emitting layer 50, the hole injection layer 20 is connected to the anode 10, the electron blocking layer 40 is connected to the light emitting layer 50, and the hole transport layer 30 is disposed between the hole injection layer 20 and the electron blocking layer 40. The hole blocking layer 60, the electron transport layer 70, and the electron injection layer 80 are disposed between the light emitting layer 50 and the cathode 90, the hole blocking layer 60 is connected to the light emitting layer 50, the electron injection layer 80 is connected to the cathode 90, and the electron transport layer 70 is disposed between the hole blocking layer 60 and the electron injection layer 80. In an exemplary embodiment, the hole injection layer 20 is configured to lower a potential barrier for injecting holes from the anode, so that holes can be efficiently injected from the anode into the light emitting layer 50. The hole transport layer 30 is configured to achieve controlled migration of injected holes in an orderly orientation. The electron blocking layer 40 is configured to form a transport barrier for electrons, preventing electrons from migrating out of the light emitting layer 50. The light emitting layer 50 is configured to recombine electrons and holes to emit light. The hole blocking layer 60 is configured to form a transport barrier for holes, preventing holes from migrating out of the light emitting layer 50. The electron transport layer 70 is configured to effect controlled migration of the injected electrons in an orderly orientation. The electron injection layer 80 is configured to lower a potential barrier of electrons injected from the cathode so that electrons can be efficiently injected from the cathode to the light emitting layer 50. The light extraction layer 100 is disposed on a side of the cathode 90 remote from the anode 10. In an exemplary embodiment, the light emitting layer 50 emits light under the action of the anode 10 and the cathode 90, and the light extraction layer 100 is configured to improve the light emitting efficiency.

In an exemplary embodiment, the materials and structures of the second light extraction sub-layer are the same as or similar to those of the previous embodiment, and will not be described again here. The material of the first light extraction sub-layer may be a material having a higher refractive index than the material of the second light extraction sub-layer.

In an exemplary embodiment, the anode may employ a material having a high work function. For the bottom emission type, a transparent oxide material such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO) may be used for the anode, and the thickness of the anode may be about 80nm to 200nm. For the top emission type, the anode may have a composite structure of metal and transparent oxide, such as Ag/ITO, ag/IZO or ITO/Ag/ITO, etc., and the thickness of the metal layer in the anode may be about 80nm to 100nm, and the thickness of the transparent oxide in the anode may be about 5nm to 20nm, so that the average reflectivity of the anode in the visible light region is about 85% to 95%.

In an exemplary embodiment, for a top emission type OLED, the cathode may be formed using a metal material formed through an evaporation process, the metal material may be magnesium (Mg), silver (Ag), or aluminum (Al), or an alloy material such as an alloy of Mg: ag, the Mg: ag ratio being about 9:1 to 1:9, and the thickness of the cathode may be about 10nm to 20nm, such that the average transmittance of the cathode at a wavelength of 530nm is about 50% to 60%. For bottom-emitting OLEDs, the cathode may be magnesium (Mg), silver (Ag), aluminum (Al), or an alloy of Mg: ag, and the thickness of the cathode may be greater than about 80nm, resulting in good reflectivity of the cathode.

In an exemplary embodiment, the hole injection layer may employ an inorganic oxide such as molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, or manganese oxide, or the like, or may employ a p-type dopant of a strong electron-withdrawing system and a dopant of a hole transport material such as hexacyanohexaazatriphenylene, 2,3,5, 6-tetrafluoro-7, 7', 8' -tetracyanoquinodimethane (F4 TCNQ), or 1,2, 3-tris [ (cyano) (4-cyano-2, 3,5, 6-tetrafluorophenyl) methylene ] cyclopropane, or the like.

In an exemplary embodiment, the hole injection layer may have a thickness of about 5nm to 20nm.

In an exemplary embodiment, the hole transport layer and the electron blocking layer may employ arylamine or carbazole materials having hole transport characteristics, such as 4,4' -bis [ N- (1-naphthyl) -N-phenylamino ] biphenyl (NPB), N ' -bis (3-methylphenyl) -N, N ' -diphenyl- [1,1' -biphenyl ] -4,4' -diamine (TPD), 4-phenyl-4 ' - (9-phenylfluoren-9-yl) triphenylamine (BAFLP), 4' -bis [ N- (9, 9-dimethylfluoren-2-yl) -N-phenylamino ] biphenyl (DFLDPBi), 4' -bis (9-Carbazolyl) Biphenyl (CBP), 9-phenyl-3- [4- (10-phenyl-9-anthracenyl) phenyl ] -9H-carbazole (PCzPA), or 4,4',4 "-tris (N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA), and the like.

In an exemplary embodiment, the hole transport layer may have a thickness of about 60nm to 150nm, and the electron blocking layer may have a thickness of about 5nm to 20nm.

In an exemplary embodiment, the light emitting layer material may include one material, or may include a mixture of two or more materials. The light emitting material is classified into a blue light emitting material, a green light emitting material, and a red light emitting material. The blue light emitting material may include a pyrene derivative, an anthracene derivative, a fluorene derivative, a perylene derivative, a styrylamine derivative, a metal complex, or the like. For example, N1, N6-bis ([ 1,1 '-biphenyl ] -2-yl) -N1, N6-bis ([ 1,1' -biphenyl ] -4-yl) pyrene-1, 6-diamine, 9, 10-bis- (2-naphthyl) Anthracene (ADN), 2-methyl-9, 10-bis-2-naphtyl anthracene (MADN), 2,5,8, 11-tetra-tert-butylperylene (TBPe), 4 '-bis [4- (diphenylamino) styryl ] biphenyl (BDAV Bi), 4' -bis [4- (di-p-tolylamino) styryl ] biphenyl (DPAVBi), or bis (4, 6-difluorophenylpyridine-C2, N) picolinic iridium (FIrpic).

The green luminescent material may include, for example, coumarin dyes, quinacridone derivatives, polycyclic aromatic hydrocarbons, diamine anthracene derivatives, carbazole derivatives, metal complexes, or the like. For example, coumarin 6 (C-6), coumarin 545T (C-525T), quinacridone (QA), N ' -Dimethylquinacridone (DMQA), 5, 12-Diphenylnaphthyridine (DPT), N10' -diphenyl-N10, N10' -dibenzoyl-9, 9' -dianthracene-10, 10' -diamine (abbreviated as BA-NPB), tris (8-hydroxyquinoline) aluminum (III) (abbreviated as Alq 3), tris (2-phenylpyridine) iridium (Ir (ppy) 3), bis (2-phenylpyridine) iridium acetylacetonate (Ir (ppy) 2 (acac)). The red light emitting material may include, for example, a DCM series material or a metal complex or the like. For example, 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 4- (dicyanomethylene) -2-tert-butyl-6- (1, 7-tetramethyl-julolidine-9-enyl) -4H-pyran (DCJTB), bis (1-phenylisoquinoline) (acetylacetonato) iridium (III) (Ir (piq) 2 (acac)), octaethylporphyrin platinum (PtOEP for short), bis (2- (2 '-benzothienyl) pyridine-N, C3') (acetylacetonato) iridium (Ir (btp) 2 (acac) for short), and the like.

In an exemplary embodiment, the light emitting layer including two or more mixed materials may include a host material and a guest material, and the doping ratio of the guest material is 1% to 20%. In the doping proportion range, the host material can effectively transfer exciton energy to the guest material to excite the guest material to emit light, and the host material 'dilutes' the guest material, so that the inter-molecular collision of the guest material and the fluorescence quenching caused by the inter-energy collision can be effectively improved, and the luminous efficiency and the service life of the device are improved.

In exemplary embodiments of the present disclosure, the doping ratio refers to a ratio of the mass of the guest material to the mass of the light emitting layer, i.e., mass percent. In an exemplary embodiment, the host material and the guest material may be co-evaporated by a multi-source evaporation process to uniformly disperse the host material and the guest material in the light emitting layer, and the doping ratio may be controlled by controlling the evaporation rate of the guest material during the evaporation process or by controlling the evaporation rate ratio of the host material and the guest material.

In an exemplary embodiment, the thickness of the light emitting layer 50 may be about 10nm to 25nm.

In an exemplary embodiment, the hole blocking layer and the electron transporting layer may employ an aromatic heterocyclic compound having a hole blocking layer property, and may include, for example, imidazole derivatives such as diazaphosphole, phosphine oxide compound, borane compound, aromatic ketone compound, lactam compound, benzimidazole derivative, imidazopyridine derivative, benzimidazole benzophenanthridine derivative, and the like; pyrimidine derivatives, triazine derivatives and other oxazine derivatives; any one or more of quinoline derivatives, isoquinoline derivatives, phenanthroline derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline derivatives or diazole derivatives. For example, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3, 4-oxadiazole (PBD), 1, 3-bis [5- (p-tert-butylphenyl) -1,3, 4-oxadiazol-2-yl ] benzene (OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenyl) -1,2, 4-Triazole (TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenyl) -1,2, 4-triazole (p-EtTAZ), bathophenanthroline (BPhen), bathocuproine (BCP), 4' -bis (5-methylbenzoxazol-2-yl) stilbene (BzOs) or 1,3, 5-tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBi), and the like.

In an exemplary embodiment, the electron injection layer may employ an alkali metal or metal, such as lithium fluoride (LiF), ytterbium (Yb), magnesium (Mg), or calcium (Ca), or a compound of these alkali metals or metals, or the like.

In an exemplary embodiment, the electron injection layer may have a thickness of about 0.5nm to 2nm.

In an exemplary embodiment, for a top-emitting OLED, the thickness of the organic light-emitting layer between the cathode and anode may be designed to meet the optical path requirements of the optical microresonator to obtain optimal light output intensity and color.

In an exemplary embodiment, a display substrate including an OLED may be prepared using the following preparation method.

First, a driving circuit layer is formed on a substrate through a patterning process, and the driving circuit layer of each sub-pixel may include a driving transistor and a storage capacitor constituting a pixel driving circuit.

Subsequently, a planarization layer is formed on the substrate on which the foregoing structure is formed, and a via hole exposing the drain electrode of the driving transistor is formed on the planarization layer of each sub-pixel.

Then, on the substrate on which the foregoing structure is formed, an anode is formed by a patterning process, and the anode of each sub-pixel is connected to the drain electrode of the driving transistor through a via hole on the planarization layer.

Then, on the substrate on which the foregoing structure is formed, a pixel defining layer is formed by patterning, and pixel openings exposing the anode are formed on the pixel defining layer of each sub-pixel, each pixel opening serving as a light emitting region of each sub-pixel.

Then, on the substrate with the structure, an Open Mask (Open Mask) is firstly adopted to sequentially evaporate the hole injection layer and the hole transport layer, and a common layer of the hole injection layer and the hole transport layer, namely the hole injection layers of all the sub-pixels are communicated, and the hole transport layers of all the sub-pixels are communicated, is formed on the display substrate. For example, the hole injection layer and the hole transport layer are substantially the same in area and different in thickness.

Subsequently, an electron blocking layer and a red light emitting layer, an electron blocking layer and a green light emitting layer, and an electron blocking layer and a blue light emitting layer are respectively evaporated on different sub-pixels by using a Fine Metal Mask (FMM), and the electron blocking layers and the light emitting layers of adjacent sub-pixels may be slightly overlapped (for example, overlapped portions occupy less than 10% of the area of the respective light emitting layer patterns) or may be isolated.

And then, sequentially evaporating a hole blocking layer, an electron transmission layer, an electron injection layer and a cathode by adopting an open mask, and forming a common layer of the hole blocking layer, the electron transmission layer, the electron injection layer and the cathode on the display substrate, wherein the hole blocking layers of all the sub-pixels are communicated, the electron transmission layers of all the sub-pixels are communicated, the electron injection layers of all the sub-pixels are communicated, and the cathodes of all the sub-pixels are communicated.

In an exemplary embodiment, the light emitting layer may be formed by multi-source co-evaporation, and the doping ratio may be controlled by controlling the evaporation rate of the guest material during evaporation, or by controlling the evaporation rate ratio of the host material and the guest material.

In an exemplary embodiment, the orthographic projection of one or more of the hole injection layer, the hole transport layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode onto the substrate is continuous. In some examples, at least one of the hole injection layer, the hole transport layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode of at least one row or column of subpixels are in communication. In some examples, at least one of the hole injection layer, the hole transport layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode of the plurality of sub-pixels are in communication.

In an exemplary embodiment, the organic light emitting layer may include a microcavity conditioning layer located between the hole transport layer and the light emitting layer. For example, after the hole transport layer is formed, a fine metal mask may be used to vapor deposit a red microcavity adjustment layer and a red light-emitting layer, a green microcavity adjustment layer and a green light-emitting layer, and a blue microcavity adjustment layer and a blue light-emitting layer, respectively, at different sub-pixels. In an exemplary embodiment, the red microcavity conditioning layer, the green microcavity conditioning layer, and the blue microcavity conditioning layer may include an electron blocking layer.

In an exemplary embodiment, since the hole blocking layer is a common layer and the light emitting layers of different sub-pixels are isolated, the orthographic projection of the hole blocking layer on the substrate includes the orthographic projection of the light emitting layer on the substrate, and the area of the hole blocking layer is larger than the area of the light emitting layer.

In an exemplary embodiment, since the hole blocking layer is a common layer, the orthographic projection of the hole blocking layer on the substrate includes the orthographic projection of the light emitting regions of at least two sub-pixels on the substrate.

In an exemplary embodiment, the front projection of the light emitting layer of at least part of the sub-pixels on the substrate overlaps with the front projection driven on the substrate by the pixel driving circuit.

In an exemplary embodiment, the display substrate may include an encapsulation layer, which may be encapsulated with a cover plate, or may be encapsulated with a thin film.

In an exemplary embodiment, the display substrate may include a light extraction layer, and the light extraction layer may further be provided with a first light extraction sub-layer and a second light extraction sub-layer, and be encapsulated with a thin film.

The organic electroluminescent device performance test and comparison of the materials of the present disclosure containing the second light extraction sub-layer were performed using the device structures, materials and thicknesses shown in table 3 below.

TABLE 3 organic electroluminescent device structure and thickness

The materials of the second light extraction sublayer CPL2 in table 3 include compounds shown in the embodiments of the present disclosure as formulas (1) to (24), the materials of the first light extraction sublayer CPL1 include compounds shown in CP1, and the structural formulas of the materials used in table 3 are shown in table 4.

TABLE 4 structural materials for organic electroluminescent devices

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According to the structure, material and thickness data of the top-emission organic electroluminescent devices shown in tables 3 and 4, corresponding organic electroluminescent devices were prepared from the compound LiF of comparative example 1 and the materials of the compounds shown in examples 1 and 2 of the present disclosure as the materials of the second light extraction sub-layer CPL2, respectively, and the measured results of the performance test of the blue organic electroluminescent devices are shown in table 5.

TABLE 5 blue organic electroluminescent device Performance test results

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As can be seen from the test results of table 5, compared with the blue organic electroluminescent device prepared by using LiF material as the second light extraction sublayer of comparative example 1, the External Quantum Efficiency (EQE) was improved by 10% to 12% and the lifetime was prolonged by 3% to 6% while maintaining the voltage unchanged. Therefore, the blue light organic electroluminescent device prepared by adopting the light extraction layer material as the second light extraction sublayer has higher light extraction efficiency, better stability and improved efficiency and service life. Furthermore, the embodiment of the disclosure also adopts the comparative experiment method to detect the performances of the red light organic electroluminescent device and the green light organic electroluminescent device, and the obtained detection result is similar to that of the blue light organic electroluminescent device.

As can be seen from the above experimental data in the embodiments of the present disclosure, the material of the second light extraction sublayer according to the embodiments of the present disclosure has the characteristics of higher effect, better thermal stability, and longer service life by increasing the molecular volume, while keeping the polarization rate of the organic molecules unchanged or increasing to a certain extent, and the increase of the molecular volume is greater than the increase of the molecular polarization rate, so that the refractive index of the compound containing the five-membered heterocyclic structure can be effectively reduced.

Fig. 7 is a schematic diagram of a display substrate structure according to an exemplary embodiment of the disclosure, illustrating a structure of three sub-pixels of an OLED display substrate. As shown in fig. 7, the display substrate may include, on a plane perpendicular to the display substrate, a driving circuit layer 102 disposed on a base 101, a light emitting structure layer 103 disposed on a side of the driving circuit layer 102 away from the base 101, a light extraction layer 100 disposed on a side of the light emitting structure layer 103 away from the base 10, and a package layer 104 disposed on a side of the light extraction layer 100 away from the base 101. In an exemplary embodiment, the driving circuit layer 103 may include a transistor 210 and a storage capacitor 211.

In an exemplary embodiment, the display substrate may include a red subpixel PR emitting red light, a green subpixel PG emitting green light, and a blue subpixel PB emitting blue light, the light extraction layer 100 may be isolated, and the light extraction layer 100 may include a red light modulation layer 100R, a green light modulation layer 100G, and a blue light modulation layer 100B sequentially disposed, the red light modulation layer 100R disposed at the red subpixel PR and configured to extract red light, the green light modulation layer 100G disposed at the green subpixel PG and configured to extract green light, and the blue light modulation layer 100B disposed at the blue subpixel PB and configured to extract blue light.

In an OLED display substrate, a packaging layer is directly covered on a cathode of a light-emitting structure layer, so that the problem of low light-emitting efficiency and the like exists. According to the embodiment of the disclosure, the light extraction layer is arranged between the light emitting structure layer and the packaging structure layer, so that the light emitting efficiency of the OLED display device is effectively improved.

In an exemplary embodiment, the manufacturing process of the display substrate of this example is substantially similar to that of the previous example, except that after the light emitting structure layer is manufactured, the light extraction layer is deposited or evaporated using an open mask, a common layer of the light extraction layer is formed on the display substrate, and then the encapsulation layer is formed on the light extraction layer.

The disclosure also provides a display device comprising the display substrate. The display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, a vehicle-mounted display, a smart watch, a smart bracelet and the like.

While the embodiments disclosed in the present disclosure are described above, the embodiments are only employed for facilitating understanding of the present disclosure, and are not intended to limit the present disclosure. Any person skilled in the art will recognize that any modifications and variations can be made in the form and detail of the present disclosure without departing from the spirit and scope of the disclosure, which is defined by the appended claims.

Claims

1. A compound containing a five-membered heterocyclic structure, which is characterized in that the compound containing the five-membered heterocyclic structure comprises at least one structural general formula shown in a formula (I) and a formula (II):

wherein X is N or C (H); y is O or S;

2. The compound of claim 1, wherein formula (i) comprises at least one of the structures of formulas (i-1), (i-2), (i-3) and (i-4):

wherein R1, R2 and R3, and L1, L2 and L3 are as defined in formula (I).

3. The compound of claim 1, wherein formula (ii) comprises at least one of the structures of formulas (ii-1), (ii-2), (ii-3) and (ii-4):

Wherein R1, R2 and R3, and L1, L2 and L3 are as defined in formula (II).

4. The compound containing a five-membered heterocyclic ring structure according to claim 1, wherein at least one of-L1-R1, -L2-R2 and-L3-R3 comprises a structure as shown in formula (iii):

wherein X1, Y1, Z1 are each independently N, C (R11) or C (H);

5. The compound containing a five-membered heterocyclic ring structure according to claim 1, wherein-L1-R1, -L2-R2 and-L3-R3 comprise at least one structure as in formula (iv) and formula (v):

wherein X2, Y2, Z2 are each independently N or C (H);

6. A compound containing a five-membered heterocyclic structure as described in any one of claims 1 to 3, wherein the compound containing a five-membered heterocyclic structure comprises any one of the following compounds:

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7. A compound containing a five-membered heterocyclic structure as described in any one of claims 1 to 3, wherein the refractive index of the compound containing a five-membered heterocyclic structure is 1.499 to 1.727 in the wavelength range of 450nm to 480 nm.

8. A compound containing a five-membered heterocyclic structure as described in any one of claims 1 to 3, wherein the conversion temperature of the compound containing a five-membered heterocyclic structure is 89 ℃ to 167 ℃.

9. Use of a compound containing a five-membered heterocyclic structure as described in any one of claims 1 to 8, as an electroluminescent organic material in an electronic device.

10. The use of a compound containing a five-membered heterocyclic structure according to claim 9, wherein the electroluminescent organic material is a light extraction layer material.

11. The organic electroluminescent device is characterized by comprising an anode, a light emitting layer, a cathode and a light extraction layer which are stacked, wherein the light emitting layer is arranged between the anode and the cathode, the light extraction layer is arranged on one side of the cathode away from the anode, the light extraction layer comprises a first light extraction sub-layer and a second light extraction sub-layer which are stacked, and the refractive index of the second light extraction sub-layer is smaller than that of the first light extraction sub-layer;

Wherein the material of the second light extraction sub-layer comprises the compound containing a five-membered heterocyclic structure according to any one of 1 to 8.

12. A display device comprising the organic electroluminescent device of claim 11.