Light-emitting device and display panel

Abstract

The embodiments of the present disclosure relate to the technical field of display. Provided are a light-emitting device and a display panel, which are used for improving the light-emitting efficiency and the device service life of the light-emitting device. The light-emitting device comprises a cathode and an anode which are oppositely arranged, and at least one light-emitting unit is arranged between the cathode and the anode. The light-emitting unit comprises: a light-emitting layer and a first-type functional layer arranged on the side of the light-emitting layer close to the anode, the first-type functional layer comprising a first sub-functional layer and a second sub-functional layer, the material of the first sub-functional layer comprising a first functional material, and the material of the second sub-functional layer comprising a second functional material. The overlapping ratio of the HOMO state density of the first functional material to the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%. The described light-emitting device is used for displaying images.

Description

Light-emitting device and display panel

[0001] This application claims priority to Chinese patent application No. 202311121381.4 filed on August 31, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present disclosure relates to the field of display technology, and in particular to a light-emitting device and a display panel. Background Art

[0003] Organic Light Emitting Diode (OLED) display panels have the advantages of self-luminescence, high color gamut, high saturation, and high response speed. They are widely used in display screens such as mobile phones, tablets, and car displays.

[0004] Summary of the Invention

[0005] In one aspect, a light-emitting device is provided. The light-emitting device includes a cathode and an anode disposed opposite each other, and at least one light-emitting unit disposed between the cathode and the anode. The light-emitting unit includes: a light-emitting layer and a first-type functional layer disposed on the anode-proximal side of the light-emitting layer; the first-type functional layer includes a first sub-functional layer and a second sub-functional layer; the material of the first sub-functional layer includes a first functional material, and the material of the second sub-functional layer includes a second functional material. The overlap ratio of the HOMO state density of the first functional material and the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%.

[0006] In some embodiments, the first sub-functional layer contacts the light-emitting layer; the material of the light-emitting layer includes a host material; wherein the overlap rate of the HOMO state density of the first functional material and the HOMO state density of the host material is greater than 0% and less than or equal to 90%.

[0007] In some embodiments, the material of the light-emitting layer further includes a guest material; and at least one of the host material, the guest material, and the first functional material is a deuterated material.

[0008] In some embodiments, the absolute value of the difference between the electron reorganization energy and the hole reorganization energy of the host material is less than or equal to 0.1 eV; and / or the hole mobility of the host material is greater than the electron mobility of the host material.

[0009] In some embodiments, the first functional material has a dipole moment greater than 0D.

[0010] In some embodiments, the lowest bond dissociation energy of the first functional material in the ground state is greater than or equal to 2.40 eV; and / or the lowest bond dissociation energy of the first functional material in the anionic state is greater than or equal to 1.0 eV.

[0011] In some embodiments, the lowest bond dissociation energy of the host material in the ground state is greater than or equal to 1.50 eV; and / or the lowest bond dissociation energy of the guest material in the ground state is greater than or equal to 1.50 eV.

[0012] In some embodiments, the triplet energy level of the host material is smaller than the triplet energy level of the guest material; and / or the singlet energy level of the host material is larger than the singlet energy level of the guest material.

[0013] In some embodiments, the light-emitting unit further comprises a second functional layer disposed on the cathode side of the light-emitting layer; the second functional layer comprises a third subfunctional layer, the third subfunctional layer being in contact with the light-emitting layer; and the third subfunctional layer comprises a third functional material. The triplet energy level of the host material is lower than the triplet energy level of the third functional material; and / or the triplet energy level of the host material is lower than the triplet energy level of the first functional material.

[0014] In some embodiments, the host material is selected from any one of the structures represented by the following general formula (I).

[0015] wherein R1, R2, R3, R4, R5, R6, R7, and R8 are the same or different and are independently selected from hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted diarylamino, substituted or unsubstituted siloxane, and substituted or unsubstituted silyl. L1 and L2 are the same or different and are independently selected from a single bond, a substituted or unsubstituted arylene, and a substituted or unsubstituted heteroarylene. Ar1 and Ar2 are the same or different and are independently selected from a substituted or unsubstituted aryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, L1, L2, Ar1, and Ar2 contains deuterium.

[0016] In some embodiments, when the host material is a deuterated material, the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%.

[0017] In some embodiments, the guest material is selected from any one of the structures represented by the following general formula (II).

[0018] Wherein, A, E and F are the same or different and are independently selected from any one of substituted or unsubstituted aromatic rings, substituted or unsubstituted heteroaromatic rings and substituted or unsubstituted cycloalkane rings; in the case where A, E and F are selected from any one of substituted aromatic rings, substituted heteroaromatic rings and substituted cycloalkane rings, the substituents may be linked with adjacent substituents to form a substituted or unsubstituted ring. X1 and X2 are the same or different and are independently selected from O, N(R a ) and C(R b R c ) in any one of R a 、R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted silyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic groups. At least one of A, E, and F contains deuterium.

[0019] In some embodiments, the substituent of at least one of A, E, and F comprises tert-butyl.

[0020] In some embodiments, when the guest material is a deuterated material, the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%.

[0021] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (III).

[0022] Wherein, Z is selected from O, S, N (R d ) and C(R e R f ) in any one of R d 、R e and R f are the same or different and are independently selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. L3 and L4 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene and a substituted or unsubstituted heteroarylene. e and f are the same or different and are independently selected from any one of 1, 2, 3 and 4. Ar3, Ar4, Ar5 and Ar6 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl and a substituted or unsubstituted C2-C60 heteroaryl; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O and S. p and q are the same or different and are independently selected from any one of 0, 1 and 2; and the sum of p and q is greater than or equal to 1 and less than or equal to 2.

[0023] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (III-A).

[0024] wherein g and h are the same or different and are independently selected from any one of 0, 1, 2 and 3.

[0025] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (IV).

[0026] Wherein, L5 is selected from any one of a single bond and a substituted or unsubstituted C6-C60 arylene group. Ar7 and Ar8 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S. R9 and R 10 are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C6-C60 aryl, and substituted or unsubstituted C2-C60 heteroaryl; or may be connected with adjacent substituents to form a substituted or unsubstituted ring; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O, and S. m and n are the same or different and are independently selected from any one of 1, 2, 3, and 4. At least one R9 is deuterium. At least one R 10 For deuterium.

[0027] In some embodiments, when the first functional material is a deuterated material, the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

[0028] In some embodiments, a light-emitting device includes at least two light-emitting units, the at least two light-emitting units being stacked. The light-emitting device also includes a charge generation layer located between two adjacent light-emitting units; the charge generation layer includes a hole generation layer and an electron generation layer being stacked; the electron generation layer is closer to the anode than the hole generation layer.

[0029] In some embodiments, the second functional material has a structural formula as shown below.

[0030] In some embodiments, the light emitting device is configured to emit light of a first wavelength, and the light of the first wavelength is blue light.

[0031] In another aspect, a display panel is provided. The display panel includes a plurality of light-emitting devices according to any one of the above embodiments and a plurality of pixel driving circuits. The pixel driving circuits are electrically connected to the light-emitting devices and configured to drive the light-emitting devices to emit light.

[0032] In another aspect, a display panel is provided. The display panel includes a substrate and a plurality of light-emitting devices; the plurality of light-emitting devices are disposed on the substrate and arranged along a first direction, the first direction being parallel to the plane of the substrate; the plurality of light-emitting devices include at least one first light-emitting device, at least one second light-emitting device, and at least one third light-emitting device, the first light-emitting device being configured to emit blue light; the second light-emitting device being configured to emit green light; and the third light-emitting device being configured to emit red light; wherein each of the plurality of light-emitting devices includes a cathode and an anode disposed opposite to each other, and at least one light-emitting unit disposed between the cathode and the anode; the light-emitting unit includes a light-emitting layer; the number of light-emitting units included in each of the plurality of light-emitting devices is n, where n is a positive integer greater than or equal to 1; the thickness of the light-emitting layer of the Nth light-emitting unit of the third light-emitting device is greater than the thickness of the light-emitting layer of the Nth light-emitting unit of the second light-emitting device; and the thickness of the light-emitting layer of the Nth light-emitting unit of the second light-emitting device is greater than the thickness of the light-emitting layer of the Nth light-emitting unit of the first light-emitting device, wherein N is a positive integer less than or equal to n.

[0033] In some embodiments, the difference between the thickness of the light-emitting layer of the Nth light-emitting unit of the third light-emitting device and the thickness of the light-emitting layer of the Nth light-emitting unit of the first light-emitting device is a first thickness difference; the difference between the thickness of the light-emitting layer of the Nth light-emitting unit of the second light-emitting device and the thickness of the light-emitting layer of the Nth light-emitting unit of the first light-emitting device is a second thickness difference; the difference between the thickness of the light-emitting layer of the Nth light-emitting unit of the third light-emitting device and the thickness of the light-emitting layer of the Nth light-emitting unit of the second light-emitting device is a third thickness difference; wherein, the ratio of the first thickness difference to the second thickness difference is greater than or equal to 1.5 and less than or equal to 2; the ratio of the third thickness difference to the second thickness difference is greater than or equal to 1 and less than or equal to 1.5.

[0034] In some embodiments, the light-emitting unit also includes a first type of functional layer arranged on the anode side of the light-emitting layer; the first type of functional layer includes a first sub-functional layer in contact with the light-emitting layer; the difference between the thickness of the first sub-functional layer of the Nth light-emitting unit of the third light-emitting device and the thickness of the first sub-functional layer of the Nth light-emitting unit of the first light-emitting device is a fourth thickness difference; the difference between the thickness of the first sub-functional layer of the Nth light-emitting unit of the second light-emitting device and the thickness of the first sub-functional layer of the Nth light-emitting unit of the first light-emitting device is a fifth thickness difference; the ratio of the fourth thickness difference to the fifth thickness difference is greater than or equal to 1.1 and less than or equal to 1.5.

[0035] In some embodiments, the light-emitting unit further includes a second type of functional layer disposed on the cathode side of the light-emitting layer; the ratio of the thickness of the first type of functional layer to the thickness of the second type of functional layer is greater than or equal to 1 and less than or equal to 5.

[0036] In some embodiments, the material of the light-emitting layer includes a guest material, and the guest material is configured to emit light of a set wavelength; the relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is greater than or equal to 650 and less than or equal to 1300; and / or, the relative molecular weight of the guest material of the light-emitting layer of the second light-emitting device is greater than or equal to 700 and less than or equal to 1400; and / or, the relative molecular weight of the guest material of the light-emitting layer of the third light-emitting device is greater than or equal to 700 and less than or equal to 1500.

[0037] In some embodiments, the absolute value of the difference between the relative molecular weight of the guest material of the light-emitting layer of the third light-emitting device and the relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is less than or equal to 600; and / or the absolute value of the difference between the relative molecular weight of the guest material of the light-emitting layer of the second light-emitting device and the relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is less than or equal to 500.

[0038] In some embodiments, the difference between the relative molecular weight of the guest material in the light-emitting layer of the third light-emitting device and the relative molecular weight of the guest material in the light-emitting layer of the first light-emitting device is a first relative molecular weight difference; the difference between the relative molecular weight of the guest material in the light-emitting layer of the second light-emitting device and the relative molecular weight of the guest material in the light-emitting layer of the first light-emitting device is a second relative molecular weight difference. The ratio of the absolute value of the first relative molecular weight difference to the absolute value of the second relative molecular weight difference is greater than or equal to 0.5 and less than or equal to 6.

[0039] In some embodiments, the optical path of light in the light-emitting layer of the light-emitting unit near the anode of the first light-emitting device and the first type of functional layer is a first optical path; the optical path of light in the light-emitting layer of the light-emitting unit near the anode of the second light-emitting device and the first type of functional layer is a second optical path; and the optical path of light in the light-emitting layer of the light-emitting unit near the anode of the third light-emitting device and the first type of functional layer is a third optical path. The ratio of the third optical path to the second optical path is greater than or equal to 1.1 and less than or equal to 1.25; the ratio of the third optical path to the first optical path is greater than or equal to 1.25 and less than or equal to 1.45; and the ratio of the second optical path to the first optical path is greater than or equal to 1.05 and less than or equal to 1.25.

[0040] In some embodiments, the light-emitting device includes a first light-emitting unit and a second light-emitting unit; the first light-emitting unit is closer to the anode than the second light-emitting unit; and a ratio of a thickness of a light-emitting layer of the first light-emitting unit to a thickness of a light-emitting layer of the second light-emitting unit is greater than or equal to 0.8 and less than or equal to 1.5.

[0041] In some embodiments, when a light-emitting unit includes a first type of functional layer and a second type of functional layer, the first type of functional layer further includes a second sub-functional layer and a fourth sub-functional layer, and the fourth sub-functional layer, the second sub-functional layer, and the first sub-functional layer are arranged sequentially in a direction away from the anode; the second type of functional layer includes a third sub-functional layer, a fifth sub-functional layer, and a sixth sub-functional layer; and the sixth sub-functional layer, the fifth sub-functional layer, and the third sub-functional layer are arranged sequentially in a direction away from the cathode. The sum of the thickness of the second sub-functional layer and the thickness of the fifth sub-functional layer of the second light-emitting unit is a first thickness sum, and the sum of the thickness of the second sub-functional layer and the thickness of the fifth sub-functional layer of the first light-emitting unit is a second thickness sum. The ratio of the first thickness sum to the second thickness sum is greater than or equal to 2 and less than or equal to 4.

[0042] In some embodiments, the sum of the thickness of the first sub-functional layer of the second light-emitting unit and the thickness of the second sub-functional layer is the third thickness sum, and the sum of the thickness of the first sub-functional layer of the first light-emitting unit and the thickness of the second sub-functional layer is the fourth thickness sum; the ratio between the third thickness sum and the fourth thickness sum is greater than or equal to 2 and less than or equal to 5.

[0043] In some embodiments, the sum of the thickness of the third sub-functional layer and the thickness of the fifth sub-functional layer of the second light-emitting unit is a fifth thickness sum, and the sum of the thickness of the third sub-functional layer and the thickness of the fifth sub-functional layer of the first light-emitting unit is a sixth thickness sum. A ratio of the fifth thickness sum to the sixth thickness sum is greater than or equal to 1.5 and less than or equal to 3.

[0044] In some embodiments, when the first type of functional layer further includes a second sub-functional layer, the material of the light-emitting layer includes a host material and a guest material; the material of the first sub-functional layer includes a first functional material, and the material of the second sub-functional layer includes a second functional material. The overlap ratio of the HOMO state density of the first functional material and the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%; and / or the overlap ratio of the HOMO state density of the first functional material and the HOMO state density of the host material is greater than 0% and less than or equal to 90%.

[0045] In some embodiments, at least one of the host material, the guest material, and the first functional material is a deuterated material.

[0046] In some embodiments, the absolute value of the difference between the electron reorganization energy and the hole reorganization energy of the host material is less than or equal to 0.1 eV; and / or the hole mobility of the host material is greater than the electron mobility of the host material.

[0047] In some embodiments, the first functional material has a dipole moment greater than 0D.

[0048] In some embodiments, the lowest bond dissociation energy of the first functional material in the ground state is greater than or equal to 2.40 eV; and / or the lowest bond dissociation energy of the first functional material in the anionic state is greater than or equal to 1.0 eV.

[0049] In some embodiments, the lowest bond dissociation energy of the host material in the ground state is greater than or equal to 1.50 eV; and / or the lowest bond dissociation energy of the guest material in the ground state is greater than or equal to 1.50 eV.

[0050] In some embodiments, the triplet energy level of the host material is smaller than the triplet energy level of the guest material; and / or the singlet energy level of the host material is larger than the singlet energy level of the guest material.

[0051] In some embodiments, when the light-emitting unit further includes a third sub-functional layer, the third sub-functional layer is in contact with the light-emitting layer; the material of the third sub-functional layer includes a third functional material, wherein the triplet energy level of the host material is lower than the triplet energy level of the third functional material; and / or the triplet energy level of the host material is lower than the triplet energy level of the first functional material.

[0052] In some embodiments, the host material is selected from any one of the structures represented by the following general formula (I).

[0053] wherein R1, R2, R3, R4, R5, R6, R7, and R8 are the same or different and are independently selected from hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted diarylamino, substituted or unsubstituted siloxane, and substituted or unsubstituted silyl. L1 and L2 are the same or different and are independently selected from a single bond, a substituted or unsubstituted arylene, and a substituted or unsubstituted heteroarylene. Ar1 and Ar2 are the same or different and are independently selected from a substituted or unsubstituted aryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, L1, L2, Ar1, and Ar2 contains deuterium.

[0054] In some embodiments, when the host material is a deuterated material, the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%.

[0055] In some embodiments, the guest material is selected from any one of the structures represented by the following general formula (II).

[0056] Wherein, A, E and F are the same or different and are independently selected from any one of substituted or unsubstituted aromatic rings, substituted or unsubstituted heteroaromatic rings and substituted or unsubstituted cycloalkane rings; in the case where A, E and F are selected from any one of substituted aromatic rings, substituted heteroaromatic rings and substituted cycloalkane rings, the substituents may be linked with adjacent substituents to form a substituted or unsubstituted ring. X1 and X2 are the same or different and are independently selected from O, N(R a ) and C(R b R c ) in any one of R a 、R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted silyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic groups. At least one of A, E, and F contains deuterium.

[0057] In some embodiments, the substituent of at least one of A, E, and F comprises tert-butyl.

[0058] In some embodiments, when the guest material is a deuterated material, the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%.

[0059] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (III).

[0060] Wherein, Z is selected from O, S, N (R d ) and C(R e R f ) in any one of R d 、R e and R fare the same or different and are independently selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. L3 and L4 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene and a substituted or unsubstituted heteroarylene. e and f are the same or different and are independently selected from any one of 1, 2, 3 and 4. Ar3, Ar4, Ar5 and Ar6 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl and a substituted or unsubstituted C2-C60 heteroaryl; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O and S. p and q are the same or different and are independently selected from any one of 0, 1 and 2; and the sum of p and q is greater than or equal to 1 and less than or equal to 2.

[0061] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (III-A).

[0062] wherein g and h are the same or different and are independently selected from any one of 0, 1, 2 and 3.

[0063] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (IV).

[0064] Wherein, L5 is selected from any one of a single bond and a substituted or unsubstituted C6-C60 arylene group. Ar7 and Ar8 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S. R9 and R 10 are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C6-C60 aryl, and substituted or unsubstituted C2-C60 heteroaryl; or may be connected with adjacent substituents to form a substituted or unsubstituted ring; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O, and S. m and n are the same or different and are independently selected from any one of 1, 2, 3, and 4. At least one R9 is deuterium. At least one R 10 For deuterium.

[0065] In some embodiments, when the first functional material is a deuterated material, the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

[0066] In some embodiments, a light-emitting device includes at least two light-emitting units, the at least two light-emitting units being stacked. The light-emitting device also includes a charge generation layer located between two adjacent light-emitting units; the charge generation layer includes a hole generation layer and an electron generation layer being stacked; the electron generation layer is closer to the anode than the hole generation layer.

[0067] In some embodiments, the second functional material has a structural formula as shown below.

[0068] In some embodiments, the host material is the host material of the light-emitting layer of the first light-emitting device; the guest material is the guest material of the light-emitting layer of the first light-emitting device; the first functional material is the material of the first sub-functional layer of the first light-emitting device; and the second functional material is the material of the second sub-functional layer of the first light-emitting device. If the light-emitting unit further includes a third sub-functional layer, the third functional material is the material of the third sub-functional layer of the first light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below are schematic diagrams and are not intended to limit the actual dimensions of the products, actual processes of the methods, actual timing of signals, and the like involved in the embodiments of the present disclosure.

[0070] FIG1 is a structural diagram of a display device according to some embodiments;

[0071] FIG2 is a structural diagram of a display panel according to some embodiments;

[0072] FIG3 is a structural diagram of a display panel according to yet other embodiments;

[0073] FIG4 is a structural diagram of a display panel according to yet other embodiments;

[0074] FIG5 is a structural diagram of a display panel according to yet other embodiments;

[0075] FIG6 is a structural diagram of a light emitting device according to some embodiments;

[0076] FIG7 is a structural diagram of a light emitting device according to yet other embodiments;

[0077] FIG8 is a structural diagram of a display panel according to yet other embodiments;

[0078] FIG9 is a structural diagram of a light emitting device according to yet other embodiments;

[0079] FIG10 is a structural diagram of a display panel according to yet other embodiments;

[0080] FIG11 is a diagram showing changes in exciton intensity at different locations in a light-emitting layer according to some embodiments;

[0081] FIG12 is a molecular packing diagram during state density simulation calculation according to some embodiments;

[0082] FIG13 is a state density distribution diagram of materials for an electron blocking layer and a hole transport layer according to some embodiments;

[0083] FIG14 is a diagram illustrating a process of generating singlet excitons during triplet-triplet fusion according to some embodiments;

[0084] FIG15 is a graph showing changes in bond dissociation energy before and after deuteration of a material according to some embodiments;

[0085] FIG16 is a structural diagram of a light emitting device according to some other embodiments;

[0086] FIG. 17 is a structural diagram of a display panel according to some other embodiments. DETAILED DESCRIPTION

[0087] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0088] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0089] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0090] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0091] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0092] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0093] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within an acceptable deviation range, wherein the acceptable deviation range is as determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality can be, for example, that the difference between the two equals is less than or equal to 5% of either one.

[0094] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0095] Exemplary embodiments are described herein with reference to cross-sectional and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0096] It should be noted that, for example, 11-1 in the drawings of this disclosure indicates that component 11 belongs to component 1, and for example, 221-220 in FIG2 indicates that pixel defining layer 221 belongs to light-emitting functional layer 220, and other similar reference numerals in the drawings also follow the above description. For example, 1 / 2 in the drawings of this disclosure indicates that both structure 1 and structure 2 can refer to this structure, and for example, 101 / 100 in FIG3 indicates that both first light-emitting device 101 and light-emitting device 100 can refer to this structure, and other similar reference numerals in the drawings also follow the above description.

[0097] As shown in FIG. 1 , some embodiments of the present disclosure provide a display device 300 , which includes a display panel 200 .

[0098] The display device 300 may be, for example, an OLED (Organic Light Emitting Diode) display device 300 .

[0099] 1 , the display device 300 further includes a driver chip 310. The driver chip 310 is used to drive the display panel 200 to perform display.

[0100] In addition, the display device 300 may also include an under-screen camera and an under-screen fingerprint recognition sensor, so that the display device 300 can realize various functions such as taking pictures, recording videos, fingerprint recognition or face recognition.

[0101] The display device 300 can be any display device that displays either motion (e.g., video) or fixed (e.g., still images) and text or images. More specifically, it is contemplated that the display device 300 of the embodiments described herein can be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, video cameras, game consoles, watches, clocks, calculators, television monitors, flat-panel displays, computer monitors, automotive displays (e.g., speedometer displays), navigation systems, cockpit controls and / or displays, camera view displays (e.g., displays for rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., displays for images of a piece of jewelry), and the like.

[0102] In some embodiments, as shown in FIG2 , the display panel 200 includes a substrate 210 and a light-emitting functional layer 220 disposed on the substrate 210 . The light-emitting functional layer 220 includes a plurality of light-emitting devices 100 . The plurality of light-emitting devices 100 are arranged along a first direction X, and the first direction X is parallel to the plane where the substrate 210 is located.

[0103] For example, the substrate 210 may be a transparent substrate. The material of the substrate 210 may be a rigid material, such as glass; or the material of the substrate 210 may be a flexible material, such as polyimide.

[0104] In some examples, as shown in FIG2 , the display panel 200 further includes an array layer 230 disposed between the substrate 210 and the light-emitting functional layer 220. The array layer 230 includes a plurality of pixel driving circuits 231, wherein the pixel driving circuits 231 include a plurality of transistors TFT. Each pixel driving circuit 231 is electrically connected to a light-emitting device 100 to drive the light-emitting device 100 to emit light.

[0105] For example, in the display panel 200, the pixel driving circuit 231 can generate a driving current. Each light-emitting device 100 can emit light under the driving action of the driving current generated by the corresponding pixel driving circuit 231. The light emitted by multiple light-emitting devices 100 cooperates with each other, thereby enabling the display panel 200 to achieve a display function.

[0106] In some examples, as shown in Figure 2, the display panel 200 also includes an encapsulation layer 240, and the array layer 230, the light-emitting functional layer 220 and the encapsulation layer 240 are stacked on the substrate 210, and the array layer 230, the light-emitting functional layer 220 and the encapsulation layer 240 are arranged in sequence in a direction away from the substrate 210.

[0107] Exemplarily, the display panel 200 may be an OLED display panel. In this case, the encapsulation layer 240 covers the light-emitting device 100, encapsulating the light-emitting device 100 to prevent moisture and oxygen in the external environment from entering the display panel 200 and damaging the organic material in the light-emitting device 100, thereby shortening the life of the OLED display panel 200.

[0108] In some embodiments, as shown in Figures 2 and 3, in the display panel 200, the light-emitting functional layer 220 also includes a pixel defining layer 221 arranged on one side of the substrate 210, and the pixel defining layer 221 has multiple openings Q. Multiple light-emitting devices 100 can be arranged one-to-one corresponding to the multiple openings Q.

[0109] In some embodiments, as shown in Figures 3 to 5, the multiple light-emitting devices 100 of the display panel 200 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103. Under the action of a driving voltage, the first light-emitting device 101 is configured to emit light of a first wavelength, which is blue light, the second light-emitting device 102 is configured to emit light of a second wavelength, which is green light, and the third light-emitting device 103 is configured to emit light of a third wavelength, which is red light.

[0110] By setting up multiple light-emitting devices 100 including a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103, the brightness (grayscale) of the first light-emitting device 101, the second light-emitting device 102 and the third light-emitting device 103 can be adjusted respectively, and the display of multiple colors can be achieved through color combination and superposition, thereby realizing full-color display of the display panel 200.

[0111] It should be noted that Figures 4 and 5 are simplified schematic diagrams obtained after removing other film layers in the display panel 200 except the film layers related to the light-emitting device 100. In Figures 4 and 5, the multiple light-emitting devices 100 are, for example, a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103.

[0112] In some embodiments, as shown in FIG3 to FIG7 , the light emitting device 100 includes a stacked anode 11 and a cathode 12 , and at least one light emitting unit 13 disposed between the anode 11 and the cathode 12 . The light emitting unit 13 includes a light emitting layer 131 .

[0113] During operation, voltage is applied to the anode 11 and the cathode 12 respectively, so that an electric field is generated between the two, which can drive the holes in the anode 11 and the electrons in the cathode 12 to recombine in the light-emitting layer 131, thereby emitting light.

[0114] 3 , the anode 11 may be located on a side of the light emitting unit 13 close to the substrate 210, and the cathode 12 may be located on a side of the light emitting unit 13 away from the substrate 210. In other examples, the anode 11 may be located on a side of the light emitting unit 13 away from the substrate 210, and the cathode 12 may be located on a side of the light emitting unit 13 close to the substrate 210.

[0115] For example, in order to ensure that the light-emitting device 100 can effectively emit light, the anode 11 can be made of a material with a high work function, so that the holes in the anode 11 can be effectively migrated to the light-emitting layer 131 of the light-emitting unit 13 under the drive of the electric field, thereby combining with the electrons of the cathode 12 to emit light. The material of the anode 11 can be a transparent conductive metal oxide material, for example, the material of the anode 11 can be indium tin oxide (ITO) or indium zinc oxide (IZO). Alternatively, the anode 11 can be a composite electrode containing multiple materials, for example, the material of the anode 110 can be ITO / Ag / ITO, Ag / IZO, CNT / ITO, CNT / IZO, GO / ITO or GO / IZO, etc., wherein Ag is silver, CNT is carbon nanotube, and GO is graphene oxide.

[0116] In some examples, the cathode 12 can be made of a material with a low work function, so that the electrons of the cathode 12 can be more easily injected into the target film layer (for example, the electron injection layer 1331. For an introduction to the electron injection layer 1331, see the following content and will not be repeated here). In this way, the electrons in the cathode 12 can be effectively driven by the electric field to migrate to the light-emitting layer 131 of the light-emitting unit 13, thereby recombining with the holes in the anode 11 to emit light. In addition, the cathode 12 must also have good light transmittance and electrical conductivity. The material of the cathode 12 can be a metal material, a metal oxide or a metal alloy, such as aluminum (Al), silver (Ag), gold (Au), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium (Li), potassium (K), sodium (Na), tin (Sn), titanium (Ti), lead (Pb), samarium (Sm), yttrium (Y), indium tin oxide (ITO), magnesium silver alloy (Mg:Ag), ytterbium gold alloy (Yb:Au), ytterbium silver alloy (Yb:Ag), lithium aluminum alloy (Li:Al) or lithium calcium magnesium alloy (Li:Ca:Al), etc.; alternatively, the material of the cathode 12 can be a laminated material, such as magnesium / aluminum (Mg / Al), magnesium / silver (Mg / Ag), aluminum / silver (Al / Ag), aluminum / gold (Al / Au), ytterbium / gold (Yb / Au), ytterbium / silver (Yb / Ag), calcium / magnesium (Ca / Mg), calcium / silver (Ca / Ag), barium / silver (Ba / Ag), etc.

[0117] In some embodiments, as shown in FIG8 , a cover layer 15 is further disposed between the encapsulation layer 240 and the cathode 12 in the display panel 200. The cover layer 15 may be formed of, for example, a material with a high refractive index. The cover layer 15 can utilize the material's high refractive index to improve the light extraction efficiency of the light-emitting device 100, thereby increasing the efficiency and brightness of the light-emitting device 100 when illuminated.

[0118] It should be noted that FIG8 is a simplified schematic diagram obtained after removing the other film layers in the display panel 200 except the film layers related to the light-emitting device 100. In FIG8 , the light-emitting device 100 is, for example, the first light-emitting device 101.

[0119] In some examples, the structural formula of the material of the cover layer 15 can be as shown below.

[0120] In some examples, as shown in Figures 3, 4, 6, and 8, the light-emitting device 100 includes one light-emitting unit 13. In this case, the light-emitting device 100 is a single-layer light-emitting device, and the anode 11, the light-emitting unit 13, and the cathode 12 are stacked along the second direction Y, and the second direction Y intersects the first direction X. In other examples, as shown in Figures 5, 7, 9, and 10, the light-emitting device 100 includes multiple (for example, two) stacked light-emitting units 13. In this case, the light-emitting device 100 is a stacked light-emitting device, and the anode 11, the multiple light-emitting units 13, and the cathode 12 are stacked along the second direction Y.

[0121] Exemplarily, as shown in FIG. 3 to FIG. 10 , the second direction Y is perpendicular to the first direction X.

[0122] In some embodiments, as shown in Figures 5, 7, 9 and 10, when the light-emitting device 100 includes a plurality of light-emitting units 13, that is, when the light-emitting device 100 includes at least two light-emitting units 13, the light-emitting device 100 further includes a charge generation layer 14, and the charge generation layer 14 is located between two adjacent light-emitting units 13 among the plurality of light-emitting units 13.

[0123] Through the charge generation layer 14, multiple light-emitting units 13 can be sequentially connected in a direction perpendicular to the light-emitting surface (e.g., the second direction Y). Furthermore, the charge generation layer 14 in the stacked OLED light-emitting device 100 not only connects the light-emitting units 13 but also helps improve the efficiency of charge (holes or electrons) generation, significantly impacting the performance of the light-emitting device 100.

[0124] In some examples, as shown in FIG5 , FIG7 , FIG9 and FIG10 , the charge generation layer 14 includes an electron generation layer 141 and a hole generation layer 142 stacked together; the electron generation layer 141 is closer to the anode 11 than the hole generation layer 142 .

[0125] Exemplarily, the above-mentioned electron generation layer 141 may also be referred to as an N-type charge generation layer. The thickness of the electron generation layer 141 may be 15 nm to 25 nm. The material of the electron generation layer 141 may be an electronic type material, for example, an electronic type material containing phenanthroline or phosphine oxide. In some examples, the electron generation layer 141 contains a dopant, and the dopant may be an alkali metal, an alkaline earth metal, and an oxide thereof. Among them, the alkali metal is, for example, lithium (Li), sodium (Na), potassium (K), or cesium (Cs), and the alkaline earth metal is, for example, magnesium (Mg), strontium (Sr), barium (Ba), or radium (Ra).

[0126] For example, the hole generation layer 142 may also be referred to as a P-type charge generation layer. The thickness of the hole generation layer 142 may be 5 nm to 15 nm. The material of the hole generation layer 142 may be a hole-type material, such as N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) or N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD). In some examples, the hole generation layer 142 contains a dopant, such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN) or 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ).

[0127] In some embodiments, as shown in Figures 3 to 10, to improve the luminous efficiency of the light-emitting device 100, the light-emitting unit 13 further includes a hole transport functional layer 132, which is located on the side of the light-emitting layer 131 close to the anode 11 and in contact with the light-emitting layer 131. The hole transport functional layer 132, for example, includes at least one of a stacked hole injection layer 1321 (Hole Inject Layer, HIL), a hole transport layer 1322 (Hole Transport Layer, HTL), and an electron blocking layer 1323 (Electron Blocking Layer, EBL). When the hole transport functional layer 132 includes the hole injection layer 1321, the hole transport layer 1322, and the electron blocking layer 1323, the hole injection layer 1321, the hole transport layer 1322, and the electron blocking layer 1323 are arranged in sequence in a direction away from the anode 11, and the electron blocking layer 1323 is in contact with the light-emitting layer 131.

[0128] In some embodiments, as shown in Figures 3 to 10, to improve the luminous efficiency of the light-emitting device 100, the light-emitting unit 13 further includes an electron transport functional layer 133, which is located on the side of the light-emitting layer 131 close to the cathode 12 and in contact with the light-emitting layer 131. The electron transport functional layer 133, for example, includes at least one of a stacked electron injection layer 1331 (Electron Inject Layer, EIL), an electron transport layer 1332 (Electron Transport Layer, ETL), and a hole blocking layer 1333 (Hole Blocking Layer, EBL). When the electron transport functional layer 133 includes the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333, the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333 are arranged in sequence in a direction away from the cathode 12, and the hole blocking layer 1333 is in contact with the light-emitting layer 131.

[0129] By setting up the film layers such as the hole injection layer 1321, the hole transport layer 1322, the electron blocking layer 1323, the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333, it is equivalent to setting up transition steps between the anode 11 and the light-emitting layer 131, and between the cathode 12 and the light-emitting layer 131, thereby reducing the potential barrier height that needs to be overcome for carrier transition, thereby making the luminescence efficiency higher.

[0130] Exemplarily, the hole transport functional layer 132 is configured to transport holes and / or block electrons and excitons generated in the light-emitting layer 131. For example, the hole injection layer 1321 can be configured to lower the hole injection barrier and improve the hole injection efficiency. The hole transport layer 1322 can be configured to transport holes. The electron blocking layer 1323 can be configured to transport holes and block electrons and excitons generated in the light-emitting layer 131.

[0131] Exemplarily, the electron transport functional layer 133 is configured to transport electrons and / or block holes and excitons generated in the light emitting layer 131 .

[0132] For example, the thickness of the hole injection layer 1321 may be 5 nm to 30 nm. The material of the hole injection layer 1321 may be 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, etc.; alternatively, the material of the hole injection layer 1321 may also be a dopant containing a strong electron-withdrawing material, such as 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN) or pyrazolo[2,3-F][1,10]phenanthroline-2,3-dicarbonitrile (PPDN); alternatively, the material of the hole injection layer 1321 may also be a material obtained by P-type doping the material of the hole transport layer 1322, in which case the thickness of the hole injection layer 1321 may be 5 nm to 20 nm; the process for forming the hole injection layer 1321 is, for example, by co-evaporating the material of the hole transport layer 1322 and the P-type dopant. Among them, the structural formulas of F4TCNQ, HATCN and PPDN are as shown below.

[0133] For example, the thickness of the hole transport layer 1322 of a single-layer light-emitting device may be 100 nm to 2000 nm; the thickness of the hole transport layer 1322 of a stacked-layer light-emitting device may be 15 nm to 25 nm. The material of the hole transport layer 1322 has good hole transport characteristics and can be an aromatic amine material or a carbazole material, such as N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA), 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC), N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), (9-phenylfluorene-9-yl)triphenylamine (BAFLP), or bis[n-(9,9-dimethylfluorene-2-yl)-n-phenylamino]biphenyl (DFLDPBi). The structural formulas of NPB, TCTA, and TAPC are shown below.

[0134] For example, the thickness of the electron blocking layer 1323 of a single-layer light-emitting device can be 5 nm to 100 nm; the thickness of the electron blocking layer 1323 of a stacked light-emitting device can be 5 nm to 15 nm. The material of the electron blocking layer 1323 has excellent hole transport characteristics and can be an aromatic amine material or a carbazole material, such as 4,4'-bis(9-carbazole)biphenyl (CBP) or 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9h-carbazole (PCzPA).

[0135] For example, the thickness of the electron injection layer 1331 can be 1 nm to 10 nm. The material of the electron injection layer 1331 has the characteristics of electron transport capability, the effect of injecting electrons from the cathode 12, and good thin film forming ability. It can be an alkali metal or metal, such as lithium fluoride LiF, ytterbium Yb, magnesium Mg, calcium Ca, or a compound of the above metals.

[0136] For example, the thickness of the electron transport layer 1332 of a single-layer light-emitting device can be 20 nm to 100 nm; the thickness of the electron transport layer 1332 of a stacked light-emitting device can be 20 nm to 100 nm. The thickness of the hole blocking layer 1333 of a single-layer light-emitting device can be 5 nm to 100 nm; the thickness of the hole blocking layer 1333 of a stacked light-emitting device can be 5 nm to 15 nm. The materials of the electron transport layer 1332 and the hole blocking layer 1333 can be aromatic heterocyclic compounds, such as imidazole derivatives, pyrimidine derivatives, oxazine derivatives, compounds containing a nitrogen-containing six-membered ring structure, or compounds having a phosphine oxide-based substituent on the heterocyclic ring. Examples of imidazole derivatives include benzimidazole derivatives, imidazopyridine derivatives, or benzimidazolophenanthridine derivatives; examples of oxazine derivatives include triazine derivatives; and examples of compounds containing a nitrogen-containing six-membered ring structure include quinoline derivatives, isoquinoline derivatives, or phenanthroline derivatives. In some examples, the materials of the electron transport layer 1332 and the hole blocking layer 1333 are 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole] (OXD-7), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (p-EtTAZ), 4,7-diphenyl-1,10-phenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), or 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi). The structural formulas of BPhen and TPBi are shown below.

[0137] For example, the thickness of the light-emitting layer 131 of a single-layer light-emitting device may be 20 nm to 100 nm; the thickness of the light-emitting layer 131 of a stacked light-emitting device may be 10 nm to 20 nm.

[0138] In some embodiments, as shown in Figures 4, 5, and 10, when the multiple light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, the cathodes 12 of the multiple light-emitting devices 100 are connected throughout the layer, that is, the cathode 12 can be a common electrode shared by the multiple light-emitting devices 100. The hole injection layer 1321 of the multiple light-emitting devices 100 can also be connected throughout the layer, that is, the hole injection layer 1321 can be a common film layer shared by the multiple light-emitting devices 100. The hole transport layer 1322, the electron blocking layer 1323, the electron injection layer 1331, the electron transport layer 1332, the hole blocking layer 1333, the electron generation layer 141, and the hole generation layer 142 can also be common film layers shared by the multiple light-emitting devices 100, and will not be described in detail here.

[0139] For example, as shown in FIG. 3 , when the cathode 12 is a common electrode shared by a plurality of light-emitting devices 100 , the cathode 12 is simultaneously formed on a side of the pixel defining layer 221 away from the substrate 210 .

[0140] In some embodiments, as shown in Figures 4, 5 and 10, when the multiple light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103, the electron blocking layers 1323 of the first light-emitting device 101, the second light-emitting device 102 and the third light-emitting device 103 are independently arranged. In this way, the material of the electron blocking layer 1323 with matching performance can be selected as needed according to the different materials of the light-emitting layer 131.

[0141] Exemplarily, in the case where the light-emitting device 100 is a single-layer light-emitting device, the structure of the light-emitting device 100 (for example, the first light-emitting device 101) is as shown in Figure 6, and the light-emitting device 100 includes a stacked anode 11, a hole injection layer 1321, a hole transport layer 1322, an electron blocking layer 1323, a light-emitting layer 131, a hole blocking layer 1333, an electron transport layer 1332, an electron injection layer 1331 and a cathode 12.

[0142] Exemplarily, when the light-emitting device 100 is a single-layer light-emitting device, and the plurality of light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, the structure of the display panel 200 is, for example, as shown in FIG4, where the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 are arranged along the first direction X. Furthermore, the cathode 12 is a common electrode for the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103; the hole injection layer 1321, the hole transport layer 1322, the hole blocking layer 1333, the electron transport layer 1332, and the electron injection layer 1331 are common film layers shared by the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103; and the anode 11 is independently provided, namely, the anode 11B of the first light-emitting device 101, the anode 11G of the second light-emitting device 102, and the anode 11R of the third light-emitting device 103. The electron blocking layers 1323 are independently provided, including the electron blocking layer 1323B of the first light-emitting device 101, the electron blocking layer 1323G of the second light-emitting device 102, and the electron blocking layer 1323R of the third light-emitting device 103. The light-emitting layers 131 are independently provided, including the light-emitting layer 131B of the first light-emitting device 101, the light-emitting layer 131G of the second light-emitting device 102, and the light-emitting layer 131R of the third light-emitting device 103.

[0143] Exemplarily, when the light-emitting device 100 is a stacked light-emitting device (e.g., comprising two light-emitting units 13), the structure of the light-emitting device 100 (e.g., the first light-emitting device 101) is as shown in Figures 7 and 9, wherein the light-emitting device 100 includes a stacked anode 11, a hole transport functional layer 132, a light-emitting layer 131, an electron transport functional layer 133, an electron generating layer 141, a hole generating layer 142, a hole transport functional layer 132, a light-emitting layer 131, an electron transport functional layer 133, and a cathode 12. The hole transport functional layer 132, the light-emitting layer 131, and the electron transport functional layer 133 located near the anode 11 constitute the first light-emitting unit 13, and the hole transport functional layer 132, the light-emitting layer 131, and the electron transport functional layer 133 located near the cathode 12 constitute the second light-emitting unit 13.

[0144] Exemplarily, when the light-emitting device 100 is a stacked light-emitting device (e.g., including two light-emitting units 13), and the plurality of light-emitting devices 100 include a first light-emitting device 101, a second light-emitting device 102, and a third light-emitting device 103, the structure of the display panel 200 is, for example, as shown in FIG5 and FIG10, wherein the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 are arranged along the first direction X. Moreover, the cathode 12 is a common electrode for the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103; each hole transport functional layer 132 of the first light-emitting unit 13 and the second light-emitting unit 13, except for the electron blocking layer 1323, and each electron transport functional layer 133 of the first light-emitting unit 13 and the second light-emitting unit 13 are common film layers shared by the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103. The anode 11 of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103, the electron blocking layer 1323 and the light-emitting layer 131 of the first light-emitting unit 13, and the electron blocking layer 1323 and the light-emitting layer 131 of the second light-emitting unit 13 are independently arranged. For details on the independent arrangement, please refer to the above content and will not be repeated here.

[0145] For example, in the stacked light-emitting device, as shown in Figures 5, 7, 9, and 10, the hole transport functional layer 132 of the first light-emitting unit 13 may include a hole injection layer 1321, a hole transport layer 1322, and an electron blocking layer 1323. The hole transport functional layer 132 of the second light-emitting unit 13 may include a hole transport layer 1322 and an electron blocking layer 1323.

[0146] For example, in the stacked light-emitting device, as shown in Figures 5, 7, and 9, the electron transport functional layer 133 of the first light-emitting unit 13 may include a hole blocking layer 1333. Alternatively, as shown in Figure 10, the electron transport functional layer 133 of the first light-emitting unit 13 may include a hole blocking layer 1333 and an electron transport layer 1332.

[0147] For example, in the stacked light-emitting device, as shown in Figures 5, 7, and 10, the electron transport functional layer 133 of the second light-emitting unit 13 may include a hole blocking layer 1333, an electron transport layer 1332, and an electron injection layer 1331. Alternatively, as shown in Figure 9, the electron transport functional layer 133 of the second light-emitting unit 13 may include a hole blocking layer 1333 and an electron transport layer 1332.

[0148] In the stacked light-emitting device comprising two light-emitting units 13 , the electron-generating layer 141 can inject electrons into the first light-emitting unit 13 , and the hole-generating layer 142 can inject holes into the second light-emitting unit 13 .

[0149] In some embodiments, the material of the light emitting layer 131 includes a host material H and a guest material D.

[0150] For example, the host material H may be configured to: transport holes or electrons, and / or to recombining electrons with holes to form excitons and transfer the exciton energy to the guest material D.

[0151] For example, the guest material D may be configured to: emit photons using the exciton energy transferred from the host material H, and / or to emit photons by forming excitons from recombined electrons and holes.

[0152] In some examples, the guest material D is a fluorescent material that can emit light using singlet excitons; in other examples, the guest material D is a phosphorescent material or a delayed fluorescent material that can emit light using triplet excitons.

[0153] In some examples, the host material H includes two or more materials. For example, the host material H may include a first host material and a second host material, wherein the first host material is a hole-type material and the second host material is an electron-type material.

[0154] For example, when the plurality of light-emitting devices 100 include a first light-emitting device 101, the host material H of the first light-emitting device 101 may be an anthracene derivative, such as 9,10-di(2-naphthyl)anthracene (ADN) or 2-methyl-9,10-dinaphthylanthracene (MADN); and the guest material D of the first light-emitting device 101 may be a pyrene derivative, a fluorene derivative, a perylene derivative, a styrylamine derivative, or a metal complex, such as 2,5,8,11-tetra-tert-butylperylene (TBPe), 4,4'-bis[4-(diphenylamino)styryl]biphenyl (BDAVBi), 4,4'-bis[4-(di-p-tolylamino)styryl]biphenyl (DPAVBi), or bis(4,6-difluorophenylpyridine-C2,N)picolinyliridium (FIrpic). The structural formulas of ADN and DPAVBi are as shown below.

[0155] Exemplarily, in the case where the plurality of light-emitting devices 100 include a second light-emitting device 102, the main material H of the second light-emitting device 102 can be a coumarin dye, a quinacridone copper derivative, a polycyclic aromatic hydrocarbon, a diamine anthracene derivative or a carbazole derivative, for example, N,N'-dimethylquinacridone (DMQA), N,N'-di-1-naphthyl-N,N'-diphenyl-[9,9'-bianthracene]-10,10'-diamine; N1,N1'-di The guest material D of the second light-emitting device 102 can be a metal complex, such as tris(2-phenylpyridine)iridium (Ir(ppy)3) or di(2-phenylpyridine)iridium acetylacetonate (Ir(ppy)2(acac)). The structural formulas of CPB and Ir(ppy)3 are shown below.

[0156] Exemplarily, when the plurality of light-emitting devices 100 include a third light-emitting device 103, the host material H of the third light-emitting device 103 may be a DCM series material, for example, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulonidin-9-enyl)-4H-pyran (DCJTB), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (DCJTI) or 2,8-bis(9H-carbazol-9-yl)dibenzo[b,d]thiophene (DCzDBT). The guest material D of the third light-emitting device 103 can be a metal complex, such as bis(1-phenylisoquinoline)(acetylacetonate)iridium(III) (Ir(piq)2(acac)), platinum(II) octaethylporphyrin (PtOEP), or bis(2-(2'-benzothienyl)pyridine-N,C3')(acetylacetonate)iridium (Ir(btp)2(acac)). The structural formulas of DCzDBT and Ir(piq)2(acac) are shown below.

[0157] As mentioned in the background, in the field of organic semiconductors, OLED light-emitting devices have the advantages of self-luminescence, low power consumption, bright colors, wide viewing angle, and the ability to be prepared into flexible products. They have gradually replaced liquid crystal displays (LCDs) in the field of small and medium-sized displays and become a mainstream product. They have been successfully applied in lighting systems, communication systems, vehicle display systems, portable electronic devices, and high-definition display devices.

[0158] With the development of OLED light-emitting devices, the requirements for their efficiency, lifespan, and other performance characteristics are becoming increasingly stringent. The efficiency and lifespan of light-emitting devices are closely linked to the device structure and the optimal combination of organic materials in each film layer. Specifically, the device structure of OLED light-emitting devices has evolved from the original sandwich structure to a multilayer device structure. For a description of multilayer device structures, please refer to the previous section and will not be repeated here.

[0159] Based on the above-mentioned multi-layer device structure, under the action of the driving voltage, electrons are emitted from the cathode 12, injected through the electron injection layer 1331, and then transported to the light-emitting layer 131 through the electron transport layer 1332 and the hole blocking layer 1333. Holes are emitted from the anode 11, injected through the hole injection layer 1321, and then transported to the light-emitting layer 131 through the hole transport layer 1322 and the electron blocking layer 1323. Electrons and holes recombine in the light-emitting layer 131 to generate excitons, which then excite radiative transitions to emit light. Among them, excitons can be divided into singlet excitons and triplet excitons based on the different types of electron orbitals in the excitons, of which singlet excitons account for 25% and triplet excitons account for 75%.

[0160] Since the mobility matching and energy level matching between the functional film layers in the light-emitting device 100, as well as the characteristics of the material itself, will affect the injection and transmission of carriers inside the light-emitting device 100, and / or the formation and quenching of excitons, the interface structure of the OLED light-emitting device will affect the performance of the light-emitting device (such as current density, luminous brightness, luminous efficiency and stability, etc.).

[0161] In some implementations, the consistency of the regions where holes and electrons recombine to form excitons in the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 is relatively poor, which affects the color matching of the display panel 200 and easily causes color deviation problems.

[0162] Based on this, some embodiments of the present disclosure provide a display panel 200. As shown in FIG17 , the display panel 200 includes a plurality of light-emitting devices 100, wherein the plurality of light-emitting devices 100 include at least one first light-emitting device 101, at least one second light-emitting device 102, and at least one third light-emitting device 103. The number of light-emitting units 13 included in each light-emitting device 100 is n, where n is a positive integer greater than or equal to 1. The thickness of the light-emitting layer 131 of the Nth light-emitting unit of the third light-emitting device 103 is greater than the thickness of the light-emitting layer 131 of the Nth light-emitting unit of the second light-emitting device 102; and the thickness of the light-emitting layer 131 of the Nth light-emitting unit of the second light-emitting device 102 is greater than the thickness of the light-emitting layer 131 of the Nth light-emitting unit of the first light-emitting device 101, where N is a positive integer less than or equal to n.

[0163] For example, when n=1, that is, the light emitting device 100 is a single-layer light emitting device, the thickness H of the light emitting layer 131 of the third light emitting device 103 is REML1 , the thickness H of the light emitting layer 131 of the second light emitting device 102 GEML1 and the thickness H of the light emitting layer of the first light emitting device 101 BEML1 Satisfies: H REML1 >H GEML1 >H BEML1 .

[0164] For example, when n=2, that is, the light-emitting device 100 is a stacked light-emitting device including two light-emitting units 13, the light-emitting unit 13 close to the anode 11 can be set as the first light-emitting unit, and the light-emitting unit 13 close to the cathode 12 can be set as the second light-emitting unit. In this case, the thickness H of the light-emitting layer 131 of the first light-emitting unit 13 of the first light-emitting device 101 is BEML1 The thickness H of the light-emitting layer 131 of the first light-emitting unit 13 of the second light-emitting device 102 is GEML1 and the thickness H of the light emitting layer 131 of the first light emitting unit 13 of the third light emitting device 103 REML1 Satisfies: H REML1 >H GEML1 >H BEML1 The thickness H of the light emitting layer 131 of the second light emitting unit 13 of the first light emitting device 101 is BEML2 The thickness H of the light-emitting layer 131 of the second light-emitting unit 13 of the second light-emitting device 102 is GEML2 and the thickness H of the light emitting layer 131 of the second light emitting unit 13 of the third light emitting device 103 REML2 Satisfies: H REML2 >H GEML2 >H BEML2 .

[0165] For the description of the stacked light-emitting device when n>2, please refer to the above content and will not be repeated here.

[0166] It should be noted that the thickness mentioned here refers to the dimension of the light emitting layer 131 along the second direction Y.

[0167] It can be understood that the mobility of carriers in the light-emitting layer 131 of the third light-emitting device 103 is greater than the mobility of carriers in the light-emitting layer 131 of the second light-emitting device 102, and the mobility of carriers in the light-emitting layer 131 of the second light-emitting device 102 is greater than the mobility of carriers in the light-emitting layer 131 of the first light-emitting device 101. Through the above-mentioned arrangement, the thickness of the light-emitting layer 131 of the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 can be matched with the mobility of the carriers. In this way, the areas where holes and electrons recombine to form excitons in the first light-emitting device 101, the second light-emitting device 102, and the third light-emitting device 103 can be made relatively consistent, which can alleviate the problem of color deviation.

[0168] In some embodiments, as shown in FIG. 17 , the thickness H of the light emitting layer 131 of the Nth light emitting unit of the third light emitting device 103 is REMLN , and the thickness H of the light emitting layer 131 of the Nth light emitting unit of the first light emitting device 101 BEMLN The difference between them is the first thickness difference (H REMLN -H BEMLN ); the thickness H of the light emitting layer 131 of the Nth light emitting unit of the second light emitting device 102 GEMLN The thickness H of the light emitting layer 131 of the Nth light emitting unit of the first light emitting device 101 is BEMLN The difference between them is the second thickness difference (H GEMLN -H BEMLN ); the thickness H of the light-emitting layer of the Nth light-emitting unit of the third light-emitting device REMLN , and the thickness H of the light emitting layer 131 of the Nth light emitting unit of the second light emitting device 102 GEMLN The difference between them is the third thickness difference (H REMLN -H GEMLN ); wherein the first thickness difference (H REMLN -H BEMLN ) and the second thickness difference (H GEMLN -H BEMLN ) is greater than or equal to 1.5 and less than or equal to 2. The third thickness difference (H REMLN -H GEMLN ) and the second thickness difference (H GEMLN -H BEMLN ) is greater than or equal to 1 and less than or equal to 1.5. That is, 1.5≤(H REMLN-H BEMLN ) / (H GEMLN -H BEMLN )≤2, and 1≤(H REMLN -H GEMLN ) / (H GEMLN -H BEMLN )≤1.5.

[0169] By such an arrangement, the thickness of the light-emitting layer 131 of the second light-emitting device 102 and the thickness of the light-emitting layer 131 of the third light-emitting device 103 can be made relatively small. In this way, the driving voltage of the second light-emitting device 102 and the third light-emitting device 103 can be made relatively low, and the driving voltage of the display panel 200 can be reduced.

[0170] For example, the first thickness difference (H REMLN -H BEMLN ) and the second thickness difference (H GEMLN -H BEMLN ) can be 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0, etc.

[0171] For example, the third thickness difference (H REMLN -H GEMLN ) and the second thickness difference (H GEMLN -H BEMLN ) can be 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5, etc.

[0172] In some embodiments, as shown in FIG17 , the light-emitting unit 13 further includes a first type functional layer 132 (see FIG9 ) disposed on a side of the light-emitting layer 131 (see FIG9 ) close to the anode 11; the first type functional layer 132 includes a first sub-functional layer 1323 in contact with the light-emitting layer 131; the thickness H of the first sub-functional layer 132 of the Nth light-emitting unit of the third light-emitting device 103 is R1GN , and the thickness H of the first sub-functional layer 132 of the Nth light-emitting unit of the first light-emitting device 101 B1GN The difference between them is the fourth thickness difference (H R1GN -H B1GN ); the thickness H of the first sub-functional layer 132 of the Nth light-emitting unit of the second light-emitting device 102 G1GN The thickness H of the first sub-functional layer 132 of the Nth light-emitting unit of the first light-emitting device 101 is B1GN The difference between them is the fifth thickness difference (H G1GN -H B1GN ). The fourth thickness difference (H R1GN -H B1GN ) and the fifth thickness difference (H G1GN -H B1GN) is greater than or equal to 1.1 and less than or equal to 1.5. That is, 1.1≤(H R1GN -H B1GN ) / (H G1GN -H B1GN )≤1.5.

[0173] Exemplarily, the first functional layer 132 is a hole transport functional layer; and the first sub-functional layer 1323 is an electron blocking layer 1323 .

[0174] It can be understood that when the thickness of the light-emitting layer 131 of the second light-emitting device 102 and the thickness of the light-emitting layer 131 of the third light-emitting device 103 are relatively small, through the above-mentioned setting, the color coordinates of the first light-emitting device 101, the second light-emitting device 102 and the third light-emitting device 103 can be adjusted by adjusting the thickness of the first sub-functional layer 1323, so that the display panel 200 has a high color gamut display effect.

[0175] For example, the fourth thickness difference (H R1GN -H B1GN ) and the fifth thickness difference (H G1GN -H B1GN ) can be 1.1, 1.2, 1.3, 1.4 or 1.5, etc.

[0176] In some embodiments, as shown in Figure 17, the light-emitting unit 13 also includes a second type of functional layer 133 (see Figure 9) arranged on the side of the light-emitting layer 131 close to the cathode 12; the ratio of the thickness of the first type of functional layer 132 to the thickness of the second type of functional layer 133 is greater than or equal to 1 and less than or equal to 5.

[0177] Exemplarily, the first type functional layer 132 is a hole transport functional layer; the second type functional layer 133 is an electron transport functional layer. It should be noted that the thickness of the first type functional layer 132 can be the sum of the thicknesses of the hole transport layer 1322 and the hole injection layer 1321, or the sum of the thicknesses of the hole transport layer 1322, the hole injection layer 1321, and the electron blocking layer 1323, without limitation. Correspondingly, the thickness of the second type functional layer 133 can be the sum of the thicknesses of the electron transport layer 1332 and the electron injection layer 1331, or the sum of the thicknesses of the electron transport layer 1332, the electron injection layer 1331, and the hole blocking layer 1333, without limitation.

[0178] It is understood that, because the hole mobility of the material of the hole transport functional layer 132 is relatively high, by setting the ratio of the thickness of the first type functional layer 132 to the thickness of the second type functional layer 133 to be greater than or equal to 1 and less than or equal to 5, the thickness of the hole transport functional layer can be made relatively large. In this way, the transport of carriers can be relatively more balanced, and the region where holes and electrons recombine to form excitons can be relatively far away from the first sub-functional layer 1323 (for example, the electron blocking layer 1323). This reduces the impact of electrons and excitons on the first sub-functional layer 1323, thereby improving the lifespan of the light-emitting device 100. At the same time, through this setting, the light emitted by the light-emitting device 100 can meet the set requirements.

[0179] For example, the ratio of the thickness of the first type functional layer 132 to the thickness of the second type functional layer 133 may be 1, 2, 3, 4, or 5.

[0180] In some embodiments, the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 is BD , greater than or equal to 650, and less than or equal to 1300. That is, 650≤M BD ≤1300.

[0181] By setting in this way, the relative molecular weight M of the guest material BD in the light-emitting layer 131 of the first light-emitting device 101 can be BD It is relatively high, which can make the Tg of the guest material BD relatively high, improve the thermal stability of the guest material BD, improve the film-forming property of the guest material BD, make the film stability of the light-emitting layer 131 of the first light-emitting device 101 relatively high, and improve the life of the light-emitting device 100.

[0182] For example, the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 is BD It can be 650, 658, 757, 822, 896, 940, 980, 1019 or 1300, etc.

[0183] In some embodiments, the relative molecular weight M of the guest material GD of the light-emitting layer 131 of the second light-emitting device 102 is GD , greater than or equal to 700, and less than or equal to 1400. That is, 700≤M GD ≤1400.

[0184] By setting in this way, the relative molecular weight M of the guest material GD in the light-emitting layer 131 of the second light-emitting device 102 can be GDIt is relatively high, which can make the Tg of the guest material GD relatively high, improve the thermal stability of the guest material GD, improve the film-forming property of the guest material GD, make the film stability of the light-emitting layer 131 of the second light-emitting device 102 relatively high, and improve the life of the light-emitting device 100.

[0185] For example, the relative molecular weight M of the guest material GD of the light-emitting layer 131 of the second light-emitting device 102 is GD It can be 700, 715, 716, 797, 880, 1089, 1160, 1300 or 1400, etc.

[0186] In some embodiments, the relative molecular weight M of the guest material RD of the light-emitting layer 131 of the third light-emitting device 103 is RD , greater than or equal to 700, and less than or equal to 1500. That is, 700≤M BD ≤1500.

[0187] By setting in this way, the relative molecular weight M of the guest material RD in the light-emitting layer 131 of the third light-emitting device 103 can be RD It is relatively high, which can make the Tg of the guest material RD relatively high, improve the thermal stability of the guest material RD, improve the film-forming property of the guest material RD, make the film stability of the light-emitting layer 131 of the third light-emitting device 103 relatively high, and improve the life of the light-emitting device 100.

[0188] For example, the relative molecular weight M of the guest material RD of the light-emitting layer 131 of the third light-emitting device 103 is RD It can be 700, 741, 793, 1078, 1276, 1400 or 1500, etc.

[0189] In some embodiments, the relative molecular weight M of the guest material RD of the light-emitting layer 131 of the third light-emitting device 103 is RD , and the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 BD The absolute value of the difference between |M RD -M BD |, less than or equal to 600. That is, |M RD -M BD |≤600.

[0190] For example, the relative molecular weight M of the guest material RD of the light-emitting layer 131 of the third light-emitting device 103 is RD , and the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 BD The absolute value of the difference between |M RD -M BD|Can be 0, 100, 200, 300, 400, 500 or 600 etc.

[0191] In some embodiments, the relative molecular weight M of the guest material GD of the light-emitting layer 131 of the second light-emitting device 102 is GD , and the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 BD The absolute value of the difference between |M GD -M BD |, less than or equal to 500. That is, |M GD -M BD |≤500.

[0192] For example, the relative molecular weight M of the guest material GD of the light-emitting layer 131 of the second light-emitting device 102 is GD , and the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 BD The absolute value of the difference between |M GD -M BD |Can be 0, 100, 200, 300, 400 or 500 etc.

[0193] In some embodiments, the relative molecular weight M of the guest material RD of the light-emitting layer 131 of the third light-emitting device 103 is RD , and the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 BD The difference between RD -M BD ) is the first relative molecular weight difference; the relative molecular weight M of the guest material GD of the light-emitting layer 131 of the second light-emitting device 102 GD , and the relative molecular weight M of the guest material BD of the light-emitting layer 131 of the first light-emitting device 101 BD The difference between GD -M BD ) is the second relative molecular weight difference. The ratio of the absolute value of the first relative molecular weight difference to the absolute value of the second relative molecular weight difference is greater than or equal to 0.5 and less than or equal to 6. That is:

[0194] For example, the ratio of the absolute value of the first relative molecular weight difference to the absolute value of the second relative molecular weight difference can be 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 or 6.0.

[0195] In some embodiments, the optical path of light in the light-emitting layer 131 of the light-emitting unit 13 near the anode 11 of the first light-emitting device 101 and the first type functional layer 132 is a first optical path D1; the optical path of light in the light-emitting layer 131 of the light-emitting unit 13 near the anode 11 of the second light-emitting device 102 and the first type functional layer 132 is a second optical path D2; and the optical path of light in the light-emitting layer 131 of the light-emitting unit 13 near the anode 11 of the third light-emitting device 103 and the first type functional layer 132 is a third optical path D3. The ratio of the third optical path D3 to the second optical path D2 is greater than or equal to 1.1 and less than or equal to 1.25. That is, 1.1 ≤ D3 / D2 ≤ 1.25. The ratio of the third optical path D3 to the first optical path D1 is greater than or equal to 1.25 and less than or equal to 1.45. That is, 1.25 ≤ D3 / D1 ≤ 1.45. The ratio of the second optical length D2 to the first optical length D1 is greater than or equal to 1.05 and less than or equal to 1.25, that is, 1.05≤D2 / D1≤1.25.

[0196] In related art, optical path is defined as the distance light travels in a vacuum in the same amount of time. Under the conditions of constant propagation time or phase change, the distance light travels in a medium is converted to the corresponding distance it travels in a vacuum. Numerically, the optical path is equal to the refractive index of the medium multiplied by the distance light travels in the medium.

[0197] Exemplarily, in the case where the first type functional layer 132 of the light-emitting unit 13 close to the anode 11 of the light-emitting device 100 (for example, the first light-emitting device 101, the second light-emitting device 102 or the third light-emitting device 103) includes a hole injection layer 1321, a hole transport layer 1322, and an electron blocking layer 1323, the optical path D between the light-emitting layer 131 of the light-emitting unit 13 close to the anode 11 of the light-emitting device 101 and the first type functional layer 132 can be calculated by the following formula: D1 = d1 × n1 + d2 × n2 + d3 × n3 + d4 × n4

[0198] Among them, d1, d2, d3, and d4 are the thicknesses of the hole injection layer 1321, the hole transport layer 1322, the electron blocking layer 1323, and the light-emitting layer 131, respectively; n1, n2, n3, and n4 are the refractive indices of the materials of the hole injection layer 1321, the hole transport layer 1322, the electron blocking layer 1323, and the light-emitting layer 131, respectively.

[0199] Regarding the situation where the first type functional layer 132 of the light-emitting unit 13 close to the anode 11 of the light-emitting device 100 includes a hole injection layer 1321 and a hole transport layer 1322, or a hole transport layer 1322 and an electron blocking layer 1323, etc., please refer to the above description and will not be repeated here.

[0200] It can be understood that when 1.1≤D3 / D2≤1.25, 1.25≤D3 / D1≤1.45, and 1.05≤D2 / D1≤1.25, the light extraction efficiency of the third light-emitting device 103, the second light-emitting device 102 and the first light-emitting device 101 can be made relatively high. In this way, the external quantum efficiency of the third light-emitting device 103, the second light-emitting device 102 and the first light-emitting device 101 can be improved, thereby improving the efficiency of the display panel 200.

[0201] For example, the ratio between the third optical length D3 and the second optical length D2 may be 1.10, 1.15, 1.20, or 1.25.

[0202] For example, the ratio of the third optical length D3 to the first optical length D1 may be 1.25, 1.30, 1.35, 1.40, or 1.45.

[0203] For example, the ratio of the second optical length D2 to the first optical length D1 may be 1.05, 1.10, 1.15, 1.20, or 1.25.

[0204] In some embodiments, as shown in FIG17 , the light emitting device 100 includes a first light emitting unit and a second light emitting unit; the first light emitting unit is closer to the anode 11 than the second light emitting unit; the thickness H of the light emitting layer 131 of the first light emitting unit is EML1 , and the thickness H of the light emitting layer 131 of the second light emitting unit EML2 The ratio between them is greater than or equal to 0.8 and less than or equal to 1.5. That is: 0.8≤H EML1 / H EML2 ≤1.5.

[0205] It is understandable that when 0.8≤H EML1 / H EML2 ≤1.5, the thickness H of the light-emitting layer 131 of the first light-emitting unit EML1 , and the thickness H of the light emitting layer 131 of the second light emitting unit EML2 The colors of the light emitting device 100 are relatively consistent. In this way, firstly, the probability of color deviation can be reduced, so that the color purity of the light emitting device 100 is improved; secondly, the efficiency of the light emitting device 100 can be improved, so that the stacked light emitting device can achieve the expected efficiency.

[0206] For example, the thickness H of the light emitting layer 131 of the first light emitting unit is EML1 , and the thickness H of the light emitting layer 131 of the second light emitting unit EML2 The ratio between them can be 0.8, 1.0, 1.2, 1.4 or 1.5, etc.

[0207] The light emitting device 101 may be any one of the first light emitting device 101 , the second light emitting device 102 and the third light emitting device 103 , which is not limited herein.

[0208] In some embodiments, as shown in FIG17 , when the light-emitting unit 13 includes a first type functional layer 132 and a second type functional layer 133, the first type functional layer 132 further includes a second sub-functional layer 1322 and a fourth sub-functional layer 1321, and the fourth sub-functional layer 1321, the second sub-functional layer 1322 and the first sub-functional layer 1323 are arranged in sequence in a direction away from the anode 11; the second type functional layer 133 includes a third sub-functional layer 1333, a fifth sub-functional layer 1332 and a sixth sub-functional layer 1331; the sixth sub-functional layer 1331, the fifth sub-functional layer 1332 and the third sub-functional layer 1333 are arranged in sequence in a direction away from the cathode 12; wherein the thickness H of the second sub-functional layer 1322 of the second light-emitting unit 13 is 2G2 The thickness H of the fifth sub-functional layer 1332 5G2 The sum of the first thickness and (H 2G2 +H 5G2 ), and the thickness H of the second sub-functional layer 1322 of the first light-emitting unit 13 2G1 The thickness H of the fifth sub-functional layer 1332 5G1 The sum of the second thickness and (H 2G1 +H 5G1 ); the first thickness and (H 2G2 +H 5G2 ) and the second thickness and (H 2G1 +H 5G1 ) is greater than or equal to 2 and less than or equal to 4. That is, 2≤(H 2G2 +H 5G2 ) / (H 2G1 +H 5G1 )≤4.

[0209] Exemplarily, the first sub-functional layer is the electron blocking layer 1323; the second sub-functional layer is the hole transport layer 1322; the fourth sub-functional layer is the hole injection layer 1321; the third sub-functional layer is the hole blocking layer 1333; the fifth sub-functional layer is the electron transport layer 1332; and the sixth sub-functional layer is the electron injection layer 1333.

[0210] It can be understood that when the ratio between the sum of the first thickness and the sum of the second thickness is greater than or equal to 2 and less than or equal to 4, the thickness of the second light-emitting unit is relatively larger than that of the first light-emitting unit, thereby improving the light extraction efficiency of the stacked light-emitting device 100.

[0211] For example, the ratio between the first thickness sum and the second thickness sum may be 2.0, 2.5, 3.0, 3.5 or 4.0, etc.

[0212] The light emitting device 101 may be any one of the first light emitting device 101 , the second light emitting device 102 and the third light emitting device 103 , which is not limited here.

[0213] In some embodiments, as shown in FIG17 , the thickness H of the first sub-functional layer 1323 of the second light-emitting unit is 1G2 The thickness H of the second sub-functional layer 1322 2G2 The sum of the third thickness and (H 1G2 +H 2G2 ), the thickness H of the first sub-functional layer 1323 of the first light-emitting unit 1G1 The thickness H of the second sub-functional layer 1322 2G1 The sum of the fourth thickness and (H 1G1 +H 2G1 ); the third thickness and (H 1G2 +H 2G2 ) and the fourth thickness and (H 1G1 +H 2G1 ) is greater than or equal to 2 and less than or equal to 5. That is, 2≤(H 1G2 +H 2G2 ) / (H 1G1 +H 2G1 )≤5.

[0214] It can be understood that when the ratio between the sum of the third thickness and the sum of the fourth thickness is greater than or equal to 2 and less than or equal to 5, the thickness of the second light-emitting unit is relatively larger than that of the first light-emitting unit, thereby improving the light extraction efficiency of the stacked light-emitting device 100.

[0215] For example, the ratio between the third thickness sum and the fourth thickness sum may be 2.0, 2.5, 3.0, 3.5, 4.0 or 5.0, etc.

[0216] The light emitting device 101 may be any one of the first light emitting device 101 , the second light emitting device 102 and the third light emitting device 103 , which is not limited here.

[0217] In some embodiments, as shown in FIG17 , the thickness H of the third sub-functional layer 1333 of the second light-emitting unit is 3G2 The thickness H of the fifth sub-functional layer 1332 5G2 The sum of the fifth thickness and (H 3G2 +H 5G2 ), the thickness H of the third sub-functional layer 1333 of the first light-emitting unit 3G1The thickness H of the fifth sub-functional layer 1332 5G1 The sum of the sixth thickness and (H 3G1 +H 5G1 ). Fifth thickness (H 3G2 +H 5G2 ) and the sixth thickness and (H 3G1 +H 5G1 ) is greater than or equal to 1.5 and less than or equal to 3. That is, 1.5≤(H 3G2 +H 5G2 ) / (H 3G1 +H 5G1 )≤3.

[0218] It can be understood that when the ratio between the sum of the fifth thickness and the sum of the sixth thickness is greater than or equal to 1.5 and less than or equal to 3, the thickness of the second light-emitting unit is relatively larger than that of the first light-emitting unit, thereby improving the light extraction efficiency of the stacked light-emitting device 100.

[0219] For example, the ratio between the fifth thickness sum and the sixth thickness sum may be 1.5, 2.0, 2.2, 2.5 or 3.0, etc.

[0220] The light emitting device 101 may be any one of the first light emitting device 101 , the second light emitting device 102 and the third light emitting device 103 , which is not limited here.

[0221] In some implementations, when the display panel 200 includes the first light emitting device 101 , the second light emitting device 102 , and the third light emitting device 103 , the lifespan of the first light emitting device 101 is relatively short.

[0222] In other implementations, during the light-emitting process of the light-emitting device 100, the region where holes and electrons recombine to form excitons (hereinafter referred to as the exciton recombination region for ease of description) is located at the interface between the electron blocking layer 1323 and the light-emitting layer 131. In some cases, during the light-emitting process of the first light-emitting device 101, the exciton intensity at various positions along the second direction Y in the light-emitting layer 131 is, for example, as shown in FIG11. As can be seen from FIG11, compared with the middle position of the light-emitting layer 131 and the position of the light-emitting layer 131 close to the electron transport functional layer 133, the exciton intensity is relatively high on the side of the light-emitting layer 131 close to the electron blocking layer 1323. This is because the transmission rate of electrons is greater than the transmission rate of holes, resulting in the exciton recombination region being located on the side of the light-emitting layer 131 close to the electron blocking layer 1323. In this case, electrons and high-energy excitons will accumulate on the material of the electron blocking layer 1323, resulting in degradation of the material of the electron blocking layer 1323, affecting the performance (e.g., life) of the light-emitting device, and thus affecting the overall life of the display panel 200. Therefore, improving the lifespan of the light-emitting device 100 (especially the first light-emitting device 101 ) is of great significance to improving the overall lifespan of the display panel 200 .

[0223] Based on this, some embodiments of the present disclosure provide a light-emitting device 100, wherein the light-emitting unit 13 includes a first type of functional layer arranged on the side of the light-emitting layer 131 close to the anode 11; the first type of functional layer includes a first sub-functional layer and a second sub-functional layer; the material of the first sub-functional layer includes a first functional material, and the material of the second sub-functional layer includes a second functional material; wherein the overlap rate of the HOMO state density of the first functional material and the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%.

[0224] It is understood that the first type of functional layer is the hole transport functional layer 132. The first sub-functional layer may be one of the hole injection layer 1321, the hole transport layer 1322, and the electron blocking layer 1323, and the second sub-functional layer may be the other of the hole injection layer 1321, the hole transport layer 1322, and the electron blocking layer 1323.

[0225] Illustratively, the first subfunctional layer is the electron blocking layer 1323 , and the first functional material is the material of the electron blocking layer 1323 ; the second subfunctional layer is the hole transport layer 1322 , and the second functional material is the material of the hole transport layer 1322 .

[0226] In related technologies, the density of states (DOS) can be defined by the number of electron states allowed to occupy specific energy levels, such as the highest occupied molecular orbital (HOMO) energy level and the lowest unoccupied molecular orbital (LUMO) energy level.

[0227] The density of states can be obtained by simulating and calculating using molecular dynamics and quantum mechanics. The specific process is, for example, as follows: since a molecule has different conformations, when the simulation software is calculated, hundreds to thousands of molecules (for example, 500 molecules) are first simulated by molecular dynamics, and the molecules are conformationally optimized so that the optimized molecular conformations conform to the Boltzman distribution. Then, a Cell is established, and the geometric configurations of different conformations are filled into the Cell according to different weights, as shown in Figure 12. Then, the highest occupied molecular orbital (HOMO) energy level and / or the lowest unoccupied molecular orbital (LUMO) energy level are calculated by quantum mechanics. The calculated highest occupied molecular orbital energy level and / or the lowest unoccupied molecular orbital conform to the Gaussian distribution, thereby obtaining the density of states.

[0228] It is understood that the greater the overlap in the HOMO state densities of the two materials, the more conducive it is to hole transport between the two materials. When the overlap rate of the HOMO state density of the first functional material and the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%, the HOMO state density of the first functional material (e.g., the material of the electron blocking layer 1323) and the HOMO state density of the second functional material (e.g., the material of the hole transport layer 1322) overlap with each other. In this way, the hole transport rate between the first sub-functional layer (e.g., the electron blocking layer 1323) and the second sub-functional layer (e.g., the hole transport layer 1322) can be increased, thereby enhancing the hole transport effect of the first type of functional layer (i.e., the hole transport functional layer 132). In this way, the holes and electrons can be made relatively more balanced. On the one hand, the exciton recombination region can be made relatively far away from the electron blocking layer 1323, reducing the accumulation of electrons and excitons on the material of the electron blocking layer 1323, slowing down the degradation of the material of the electron blocking layer 1323, improving the stability of the material of the electron blocking layer 1323, and increasing the life of the light-emitting device 100; on the other hand, the exciton yield can be increased, the energy utilization rate can be improved, and the efficiency of the light-emitting device 100 can be improved.

[0229] In some examples, where the first subfunctional layer is an electron blocking layer 1323 and the second subfunctional layer is a hole transport layer 1322, a state density distribution diagram of the material of the electron blocking layer 1323 (i.e., the first functional material) and the material of the hole transport layer 1322 (i.e., the second functional material) is shown in FIG13 . The state density on the left side of the figure, which is within the energy range of -4.4 eV to -5.0 eV, is the HOMO state density, and the state density on the right side, which is within the energy range of -1.5 eV to -0.7 eV, is the LUMO state density. As shown in FIG13 , the HOMO state density of the material of the electron blocking layer 1323 overlaps with the HOMO state density of the material of the hole transport layer 1322 in the energy range of -4.4 eV to -4.85 eV, with a high overlap rate.

[0230] Exemplarily, the overlap rate of the HOMO state density of the first functional material (e.g., the material of the electron blocking layer 1323) and the HOMO state density of the second functional material (e.g., the material of the hole transport layer 1322) can be 1%, 5%, 10%, 30%, 50%, 70% or 90%, etc.

[0231] In some embodiments, the structural formula of the second functional material is as follows:

[0232] It should be noted that (HTL) in the above structural formula is a synonym for the structural formula and is not a part of the structural formula.

[0233] The second functional material is a material having a hole transport function. Based on the above structure, the second sub-functional layer can be a hole transport layer, or a hole injection layer.

[0234] In some embodiments, the first sub-functional layer contacts the light-emitting layer 131 ; and an overlap ratio of the HOMO state density of the first functional material and the HOMO state density of the host material is greater than 0% and less than or equal to 90%.

[0235] The above-mentioned first sub-functional layer is in contact with the light-emitting layer 131, that is, the first sub-functional layer is the layer in the first type of functional layer that is closest to the light-emitting layer 131 and is in contact with the light-emitting layer 131. For example, the first sub-functional layer can be one of the hole injection layer 1321, the hole transport layer 1322 and the electron blocking layer 1323.

[0236] Exemplarily, the first sub-functional layer is the electron blocking layer 1323 , and the first functional material is the material of the electron blocking layer 1323 .

[0237] As previously mentioned, the greater the overlap in the HOMO state densities of two materials, the more conducive it is to hole transport between the two materials. Furthermore, the host material is the primary material performing the hole transport function in the light-emitting layer 131. When the overlap between the HOMO state density of the first functional material and the HOMO state density of the host material is greater than 0% and less than or equal to 90%, the HOMO state density of the first functional material (e.g., the material of the electron blocking layer 1323) and the HOMO state density of the host material overlap, thereby increasing the hole transport rate between the first functional material (e.g., the material of the electron blocking layer 1323) and the host material, and enhancing the hole transfer effect from the first type of functional layer (i.e., the hole transport functional layer 132) to the light-emitting layer 131. In this way, the holes and electrons can be made relatively more balanced. On the one hand, the exciton recombination region can be made relatively far away from the electron blocking layer 1323, reducing the accumulation of electrons and excitons on the material of the electron blocking layer 1323, slowing down the degradation of the material of the electron blocking layer 1323, improving the stability of the material of the electron blocking layer 1323, and increasing the life of the light-emitting device 100; on the other hand, the exciton yield can be increased, the energy utilization rate can be improved, and the efficiency of the light-emitting device 100 can be improved.

[0238] For example, the overlap ratio of the HOMO state density of the first functional material (eg, the material of the electron blocking layer 1323 ) and the HOMO state density of the host material may be 2%, 8%, 10%, 30%, 50%, 75% or 90%.

[0239] In some examples, the HOMO state density of the material of electron blocking layer 1323 satisfies at least one of the following conditions (i) and (ii):

[0240] (i) The overlap ratio of the HOMO state density of the material of the electron blocking layer 1323 and the HOMO state density of the material of the hole transport layer 1322 is greater than 0% and less than or equal to 90%.

[0241] (ii) The overlap ratio of the HOMO state density of the material of the electron blocking layer 1323 and the HOMO state density of the host material is greater than 0% and less than or equal to 90%.

[0242] In some embodiments, the absolute value of the difference between the electron reorganization energy λe(H) and the hole reorganization energy λh(H) of the host material H is less than or equal to 0.1 eV. In other words, the electron reorganization energy λe(H) of the host material H and the hole reorganization energy λh(H) of the host material H satisfy the following relationship: |λe(H)-λh(H)|≤0.1 eV.

[0243] In related technologies, hole reorganization energy can be used to characterize the hole mobility of a material, and electron reorganization energy can be used to characterize the electron mobility of a material.

[0244] It can be understood that when |λe(H)-λh(H)|≤0.1eV, the difference between the hole mobility of the main material and the electron mobility of the main material is relatively small, which can make the migration rate of holes on the main material relatively consistent with the migration rate of electrons on the main material; in this way, the electrons and holes can be relatively more balanced. As mentioned above, the degradation of the material of the electron blocking layer 1323 can be slowed down, and the life of the light-emitting device 100 can be improved; at the same time, the yield of excitons can be increased, so that the efficiency of the light-emitting device 100 can be improved.

[0245] In some examples, the electron reorganization energy λe(H) of the host material H is greater than the hole reorganization energy λh(H) of the host material H, and both satisfy the following condition: λe(H)-λh(H)≤0.1eV. For example, the difference between the electron reorganization energy λe(H) of the host material H and the hole reorganization energy λh(H) of the host material H can be 0eV, 0.2eV, 0.4eV, 0.6eV, 0.8eV, or 1.0eV.

[0246] In other examples, the hole reorganization energy λh(H) of the host material H is greater than the electron reorganization energy λe(H) of the host material H, and both satisfy the following condition: λh(H)-λe(H)≤0.1eV. For example, the difference between the hole reorganization energy λh(H) of the host material H and the electron reorganization energy λe(H) of the host material H can be 0eV, 0.15eV, 0.4eV, 0.6eV, 0.85eV, or 1.0eV.

[0247] In some embodiments, the hole mobility of the host material is greater than the electron mobility of the host material.

[0248] It can be understood that when the hole mobility of the main material is greater than the electron mobility of the main material, the exciton recombination area can be relatively far away from the electron blocking layer 1323, reducing the accumulation of carriers (electrons or holes) and excitons on the material of the electron blocking layer 1323, slowing down the degradation of the material of the electron blocking layer 1323, improving the stability of the material of the electron blocking layer 1323, and improving the life of the light-emitting device 100.

[0249] In some implementations, the guest material of the light-emitting device 100 (e.g., the first light-emitting device 101) is a fluorescent material. Compared to phosphorescent materials that can emit light using triplet excitons through spin-orbit coupling, fluorescent materials do not have spin-orbit coupling. Therefore, they can only emit fluorescence by radiative deactivation of singlet excitons to the ground state, and cannot use the energy of triplet excitons with a high probability of generation for light emission. Therefore, the internal quantum efficiency (IQE) of the light-emitting device 100 using the fluorescent material as the guest material reaches its theoretical limit of 25%, which is lower than the internal quantum efficiency of the light-emitting device 100 using the phosphorescent material as the guest material (which can reach 100%). As a result, the efficiency of the light-emitting device 100 (e.g., the first light-emitting device 101) using the fluorescent material as the guest material is relatively low.

[0250] In order to increase the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) using a fluorescent material as a guest material, the triplet-triplet exciton annihilation (TTA) effect can be used to utilize triplet excitons to emit light, thereby increasing the luminous efficiency of the fluorescent material. One form of the triplet-triplet exciton annihilation (TTA) effect is the triplet-triplet fusion effect (TTF), the principle of which is: singlet excitons are generated by the collision and fusion of two triplet excitons, thereby increasing the fluorescence emission. The process is shown in Figure 14. As shown in Figure 14, after the two triplet excitons collide and fuse, S is generated with a probability of 1 / 9. n with S0, where S n Vibrational relaxation can generate a singlet exciton S1, and the process of S1 radiatively transitioning to S0 can produce fluorescent light. The probability of generating the singlet exciton S1 is, for example, five triplet excitons generating one singlet exciton S1. This indicates that the TTF effect can increase the efficiency of a light-emitting device 100 (e.g., the first light-emitting device 101) using a fluorescent material as a guest material.

[0251] However, during the TTF process, when triplet excitons collide with triplet excitons, high-energy intermediates are generated. When the energy of the intermediates is higher than the bond dissociation energy of the host material and / or the guest material, it may cause degradation of the host material and / or the guest material. Here, bond dissociation energy (BDE) can be understood as the energy required to break a specific chemical bond. Generally speaking, the higher the bond dissociation energy, the more stable the molecule, and correspondingly, the stability of the material is relatively high.

[0252] In some embodiments, at least one of the host material, the guest material, and the first functional material is a deuterated material.

[0253] It should be noted that a deuterated material refers to a material in which at least one hydrogen atom in its structure is replaced by a deuterium atom. In other words, the structure of the deuterated material contains at least one deuterium atom.

[0254] It is understandable that hydrogen atoms are common elements in OLED organic materials, deuterium is an isotope of hydrogen, and the atomic weight of deuterium is twice that of hydrogen. When the hydrogen in the compound molecule is replaced by deuterium, the chemical properties of the compound remain almost unchanged. Moreover, compared with the carbon-hydrogen bond, the carbon-deuterium bond has a shorter bond length, a higher bond dissociation energy and a lower vibration energy, which can shorten the bond length, increase the bond dissociation energy and improve the molecular stability. When the hydrogen atoms in the material molecules are replaced by deuterium atoms, the physical and chemical properties of the material will change. In order to more clearly illustrate the effect of deuteration of the material on the bond dissociation energy, Figure 15 exemplifies the change in bond dissociation energy before and after deuteration of the material. As can be seen from Figure 15, after the hydrogen atoms in the molecule are replaced by deuterium atoms, the zero-point vibration energy of the compound can be reduced (represented by V 0H Reduce to V 0D ), increase the bond dissociation energy of the compound and improve the stability.

[0255] In addition, when the material contains relatively more deuterium atoms, the energy required for the material to undergo side reactions is also relatively high. Therefore, deuteration can make the probability of the material undergoing side reactions relatively low, thereby improving the stability of the material.

[0256] In some examples, the host material is a deuterated material.

[0257] By setting this configuration, compared to a case where the host material does not contain deuterium atoms, firstly, the bond dissociation energy of the host material can be increased, making the bond dissociation energy of the host material higher than the energy of the intermediate of the TTF effect, thereby reducing the probability of degradation of the host material due to the energy of the intermediate. At the same time, the probability of side reactions in the host material can be reduced, thereby improving the stability of the host material and increasing the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101). Secondly, the energy of the intermediate of the TTF effect can be reduced, increasing the difference between the bond dissociation energy of the host material and the energy of the intermediate of the TTF effect, reducing the probability of degradation of the host material, thereby improving the stability of the host material and the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101). Thirdly, the molecular vibration of the host material can be reduced, reducing the energy loss caused by the molecular vibration of the host material, and reducing the quantum efficiency loss caused by the molecular vibration of the host material, thereby improving the efficiency of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0258] In some examples, the guest material is a deuterated material.

[0259] This arrangement, compared to a case where the guest material does not contain deuterium atoms, can firstly increase the bond dissociation energy of the guest material, making the bond dissociation energy of the guest material higher than the energy of the intermediates in the TTF effect. This reduces the probability of degradation of the guest material due to the energy of the intermediates, and at the same time reduces the probability of side reactions in the guest material, thereby improving the stability of the guest material and extending the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101). Second, it can reduce the molecular vibration of the guest material, reducing the energy loss caused by the molecular vibration of the guest material and the quantum efficiency loss caused by the molecular vibration of the guest material, thereby improving the efficiency of the light-emitting device 100 (e.g., the first light-emitting device 101). Third, when the molecular vibration of the guest material is reduced, the emission spectrum of the guest material can be narrowed, resulting in relatively high color purity of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0260] In some examples, the first functional material is a deuterated material, such as the material of the electron blocking layer 1323 .

[0261] By such a setting, compared with the case where the first functional material does not contain deuterium atoms, the bond dissociation energy of the first functional material can be increased, and at the same time, the probability of side reactions in the first functional material can be reduced, thereby improving the electrical stability of the first functional material, enhancing the electronic resistance of the first functional material, slowing down the degradation of the first functional material caused by electrons and excitons, thereby improving the stability of the first functional material and improving the life of the light-emitting device 100 (for example, the first light-emitting device 101).

[0262] In some examples, the host material, the guest material, and the first functional material are all deuterated materials.

[0263] Regarding the beneficial effects that can be achieved when the host material, the guest material and the first functional material are all deuterated materials, please refer to the previous description and will not be repeated here.

[0264] In some embodiments, the first functional material has a dipole moment greater than 0D.

[0265] It is understood that when a molecule exhibits asymmetry, the molecule is relatively more stable, and the higher the asymmetry of the molecule, the higher the stability of the molecule. When the dipole moment of the first functional material is greater than 0D, the molecules of the first functional material exhibit an asymmetric structure, which can improve the stability of the first functional material and thus increase the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0266] For example, the dipole moment of the first functional material may be 0.05D, 0.10D, 0.20D, 0.30D or 0.40D, etc.

[0267] In some examples, the dipole moment of the host material is greater than 0, for example, the dipole moment of the host material may be 0.06D, 0.10D, 0.20D, 0.25D or 0.30D, etc. In this way, the stability of the host material can be improved, thereby increasing the life of the light emitting device 100 (eg, the first light emitting device 101).

[0268] In some examples, the dipole moment of the guest material is greater than 0, for example, the dipole moment of the guest material may be 0.04D, 0.08D, 0.10D, 0.20D, or 0.25D, etc. In this way, the stability of the guest material can be improved, thereby increasing the lifespan of the light-emitting device 100 (for example, the first light-emitting device 101).

[0269] In related art, since a material molecule contains multiple chemical bonds, each chemical bond has a corresponding bond dissociation energy (BDE). The lowest bond dissociation energy refers to the energy required to break the bond at the most easily broken site in the molecule. Taking the methane molecule as an example, it contains four carbon-hydrogen bonds, and the bond dissociation energy corresponding to each carbon-hydrogen bond is different. The first hydrogen atom in the methane molecule is the easiest to lose, so the energy required to lose the first hydrogen atom is the lowest bond dissociation energy of methane.

[0270] In some embodiments, the lowest of the bond dissociation energies of the first functional material in a ground state is greater than or equal to 2.40 eV.

[0271] It is understood that the lowest bond dissociation energy of the first functional material in the ground state can be used to characterize the molecular stability of the first functional material. When the lowest bond dissociation energy of the first functional material in the ground state is greater than or equal to 2.40 eV, the molecular stability of the first functional material is relatively high, thereby improving the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0272] For example, the lowest bond dissociation energy of the first functional material in the ground state may be 2.40 eV, 2.80 eV, 3.50 eV, 4.00 eV, 4.50 eV, or 5.0 eV.

[0273] In some embodiments, the lowest bond dissociation energy of the first functional material in an anionic state is greater than or equal to 1.0 eV.

[0274] It is understood that the lowest bond dissociation energy of the first functional material in the anionic state can be used to characterize the electron resistance of the first functional material. When the lowest bond dissociation energy of the first functional material in the anionic state is greater than or equal to 1.0 eV, the electron resistance of the first functional material is relatively high. This can mitigate degradation of the first functional material caused by electrons and excitons, thereby improving the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0275] For example, the lowest bond dissociation energy of the first functional material in an anionic state may be 1.0 eV, 1.5 eV, 2.0 eV, 2.5 eV, or 3.0 eV.

[0276] In some embodiments, the lowest of the bond dissociation energies of the host material in the ground state is greater than or equal to 1.50 eV.

[0277] It is understood that the lowest bond dissociation energy of the host material in its ground state can be used to characterize the molecular stability of the host material. When the lowest bond dissociation energy of the host material in its ground state is greater than or equal to 1.50 eV, the molecular stability of the host material is relatively high, thereby improving the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0278] For example, the lowest bond dissociation energy of the host material in the ground state may be 1.50 eV, 2.00 eV, 2.50 eV, 3.00 eV, 3.50 eV, or 4.00 eV.

[0279] In some embodiments, the lowest of the bond dissociation energies of the guest material in its ground state is greater than or equal to 1.50 eV.

[0280] It is understood that the lowest bond dissociation energy of the guest material in its ground state can be used to characterize the molecular stability of the guest material. When the lowest bond dissociation energy of the guest material in its ground state is greater than or equal to 1.50 eV, the molecular stability of the guest material is relatively high, thereby improving the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0281] For example, the lowest bond dissociation energy of the guest material in the ground state may be 1.50 eV, 2.10 eV, 2.50 eV, 3.00 eV, 3.60 eV, or 4.10 eV.

[0282] In some embodiments, the triplet energy level T1(H) of the host material H is less than the triplet energy level T1(G1) of the first functional material G1. That is, the triplet energy level T1(H) of the host material H and the triplet energy level T1(G1) of the first functional material G1 satisfy the following equation: T1(H) <T1(G1)。

[0283] The first functional material G1 is the material of the sub-functional layer in the first functional layer (ie, the hole transport functional layer 132 ) that is in direct contact with the light-emitting layer 131 . For example, the first functional material G1 is the material of the electron blocking layer 1323 .

[0284] It can be understood that when the triplet energy level T1(H) of the main material H is less than the triplet energy level T1(G1) of the first functional material G1, after the holes and electrons recombine to form triplet excitons on the main material, the triplet excitons transferred from the main material to the first functional material are relatively small. In this way, the triplet excitons can be bound in the light-emitting layer 131 (for example, bound to the main material), and the concentration of triplet excitons in the light-emitting layer 131 can be increased. In this way, compared with the case where the triplet exciton concentration is low, the probability of effective collision of triplet excitons can be increased, so that the TTA effect can be enhanced, and the TTA effect can be fully utilized to improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0285] In some embodiments, the triplet energy level T1(H) of the host material H is less than the triplet energy level T1(D) of the guest material D. That is, the triplet energy level T1(H) of the host material H and the triplet energy level T1(D) of the guest material D satisfy the following equation: T1(H) <T1(D)。

[0286] It can be understood that when the triplet energy level T1(H) of the host material H is smaller than the triplet energy level T1(D) of the guest material D, after the holes and electrons recombine to form triplet excitons on the host material, the number of triplet excitons transferred from the host material to the guest material is relatively small. In this way, the triplet excitons can be bound to the host material, and the concentration of triplet excitons distributed on the host material can be increased. In this way, compared with the case where the concentration of triplet excitons on the host material is low, the probability of effective collision of triplet excitons can be increased, so that the TTA effect can be enhanced, and the TTA effect can be fully utilized to improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0287] In some embodiments, the singlet energy level S1(H) of the host material H is greater than the singlet energy level S1(D) of the guest material D. That is, the singlet energy level S1(H) of the host material H and the singlet energy level S1(D) of the guest material D satisfy: S1(H)>S1(D).

[0288] It can be understood that when the singlet energy level S1(H) of the host material H is greater than the singlet energy level S1(D) of the guest material D, the singlet excitons transferred from the guest material to the host material are relatively few. In this way, relatively more singlet excitons can be bound to the guest material, and the concentration of singlet excitons distributed on the guest material can be increased. In this way, compared with the case where the concentration of singlet excitons on the guest material is low, relatively more singlet excitons can be used for light emission, which can improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0289] In some embodiments, the light-emitting unit 13 further includes a second type of functional layer disposed on the side of the light-emitting layer 131 close to the cathode 12; the second type of functional layer includes a third sub-functional layer, which is in contact with the light-emitting layer 131; and the material of the third sub-functional layer includes a third functional material G3. The triplet energy level T1(H) of the host material H is less than the triplet energy level T1(G3) of the third functional material G3. That is, the triplet energy level T1(H) of the host material H and the triplet energy level T1(G3) of the third functional material G3 satisfy the following conditions: T1(H) <T1(G3)。

[0290] The second type of functional layer is the electron transport functional layer 133. The third sub-functional layer can be one of the electron injection layer 1331, the electron transport layer 1332, and the hole blocking layer 1333. The third functional material is the material of the sub-functional layer of the second type of functional layer (i.e., the electron transport functional layer 133) that is in direct contact with the light-emitting layer 131. For example, the third functional material G3 is the material of the hole blocking layer 1333.

[0291] It can be understood that when the triplet energy level T1(H) of the main material H is less than the triplet energy level T1(G3) of the third functional material G3, after the holes and electrons recombine to form triplet excitons on the main material, the triplet excitons transferred from the main material to the third functional material are relatively small. In this way, the triplet excitons can be bound in the light-emitting layer 131 (for example, bound to the main material), and the concentration of triplet excitons in the light-emitting layer 131 can be increased. In this way, compared with the case where the triplet exciton concentration is low, the probability of effective collision of triplet excitons can be increased, so that the TTA effect can be enhanced, and the TTA effect can be fully utilized to improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0292] The structures of the host material, the guest material, and the first functional material are exemplarily introduced below.

[0293] In some embodiments, the host material H is selected from any one of the structures represented by the following general formula (I).

[0294] wherein R1, R2, R3, R4, R5, R6, R7 and R8 are the same or different and are independently selected from any one of hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted diarylamino, substituted or unsubstituted siloxane and substituted or unsubstituted silyl.

[0295] L1 and L2 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group.

[0296] Ar1 and Ar2 are the same or different and are independently selected from substituted or unsubstituted aryl groups.

[0297] At least one of R1, R2, R3, R4, R5, R6, R7, R8, L1, L2, Ar1 and Ar2 contains deuterium.

[0298] It should be noted that when R1, R2, R3, R4, R5, R6, R7 or R8 is selected from any one of a substituted alkyl group, a substituted alkoxy group, a substituted aryl group, a substituted aryloxy group, a substituted diarylamino group, a substituted siloxane group and a substituted silyl group, and / or L1 or L2 is any one of a substituted arylene group and a substituted heteroarylene group, and / or Ar1 and Ar2 are selected from substituted aryl groups, the type and number of the substituents are not limited here.

[0299] It should be noted that, in the general formula (I), It is an anthracene group. In the above general formula (I), L1 and L2 can be a single bond. When L1 is a single bond, the anthracene group and Ar1 are directly connected by a single bond. When L2 is a single bond, the anthracene group and Ar2 are directly connected by a single bond. In the general formula (I), L1 and L2 can be any one of a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group. The structure of the arylene group is introduced below using phenylene as an example. Phenyl refers to the general term for the group remaining after the hydrogen atom of one carbon atom on the benzene ring is removed. Phenylene refers to the general term for the group remaining after the hydrogen atoms on two carbon atoms on the benzene ring are removed. For the understanding of heteroarylene groups, please refer to the above content and will not be repeated here.

[0300] It is understood that when at least one of R1, R2, R3, R4, R5, R6, R7, R8, L1, L2, Ar1, and Ar2 contains deuterium, the host material H is a deuterated material. Since the exciton recombination site mainly occurs on the host material H, the TTF effect is also mainly realized on the host material. Therefore, compared to the case where the host material H does not contain deuterium atoms, by setting the host material H as a deuterated material, the bond dissociation energy of the host material H can be increased, and the energy of the intermediate of the TTF effect can be reduced. The bond dissociation energy of the host material H is higher than the energy of the intermediate of the TTF effect, which can reduce the probability of degradation of the host material H due to the energy of the intermediate, thereby improving the stability of the host material H and the life of the light-emitting device 100 (for example, the first light-emitting device 101).

[0301] Furthermore, when the deuterated position is at the location of a carbon-hydrogen bond, a carbon-deuterium bond is generated. Carbon-hydrogen bonds are typically relatively energy-weak components in organic materials. Deuteration can replace carbon-hydrogen bonds with carbon-deuterium bonds, shortening the bond length and increasing the bond dissociation energy. This can also reduce the probability of side reactions in the host material, improving the molecular stability of the host material. This can enhance the host material's tolerance to high-energy intermediates of the TTF effect, thereby increasing the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0302] In addition, the structure shown in general formula (I) contains an anthracene group, that is, the main material H is an anthracene derivative. During the light-emitting process of the light-emitting device 100, electrons and holes can recombine at the anthracene group to form triplet excitons, so that the triplet excitons have a relatively high distribution density at the anthracene group. In this way, the collision and fusion between triplet excitons can be increased, the TTA effect (for example, the TTF effect) can be enhanced, and the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) can be improved.

[0303] An exemplary structure of the host material H having the structure represented by the general formula (I) is described below.

[0304] In some examples, when R1, R2, R3, R4, R5, R6, R7, and R8 are all deuterium, and Ar1 and Ar2 do not contain deuterium, the structural formula of the host material H can be as shown below.

[0305] In some examples, when R1, R2, R3, R4, R5, R6, R7, and R8 are all hydrogen, and Ar1 and / or Ar2 contain deuterium, the structural formula of the host material H can be as shown below.

[0306] In some examples, when R1, R2, R3, R4, R5, R6, R7, and R8 are all deuterium, and Ar1 and / or Ar2 contain deuterium, the structural formula of the host material H can be as shown below.

[0307] It should be noted that the above-listed structural formulas are examples of the structures of the host material H and are not intended to limit the host material H. Moreover, (Hx) in the above structural formulas is a synonym for each structural formula and is not part of the structural formula structure, where x is a positive integer.

[0308] In some embodiments, when the host material is a deuterated material, the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%.

[0309] The mass fraction of deuterium in the host material refers to the ratio between the relative molecular mass of deuterium atoms in the structure of the host material and the relative molecular mass of the host material molecules.

[0310] It can be understood that when the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%, the mass fraction of deuterium in the host material is relatively high, that is, the host material contains relatively more deuterium atoms. As mentioned above, when the number of deuterium atoms in the host material is relatively large, the bond dissociation energy and stability of the host material can be improved, so that the life of the light-emitting device 100 (for example, the first light-emitting device 101) is improved. At the same time, the molecular vibration of the host material can be reduced, and the quantum efficiency loss caused by the molecular vibration of the host material can be reduced, so that the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101) is improved. In addition, when the host material contains relatively more deuterium atoms, the energy required for the host material to undergo side reactions is also relatively high. In this way, the probability of side reactions in the host material can be relatively low, which can improve the stability of the host material.

[0311] Exemplarily, the host material H is selected from any one of the structures represented by general formula (I), and the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%.

[0312] For example, the mass fraction of deuterium in the host material may be 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0% or 4.9%, etc.

[0313] In some embodiments, the guest material D is selected from any one of the structures represented by the following general formula (II).

[0314] wherein A, E and F are the same or different and are independently selected from any one of a substituted or unsubstituted aromatic ring, a substituted or unsubstituted heteroaromatic ring and a substituted or unsubstituted cycloalkane ring; in the case where A, E and F are selected from any one of a substituted aromatic ring, a substituted heteroaromatic ring and a substituted cycloalkane ring, the substituent may be linked to an adjacent substituent to form a substituted or unsubstituted ring.

[0315] X1 and X2 are the same or different and are independently selected from O, N(R a ) and C(R b R c ) in any one of the following. Wherein, O is oxygen, N(R a ) is R a Substituted nitrogen, C(R b R c ) is R b With R c substituted carbon.

[0316] R a 、R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted silyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl and substituted or unsubstituted heterocyclic.

[0317] At least one of A, E and F contains deuterium.

[0318] It should be noted that in the structure shown in general formula (II), B is boron, and the relationship between X1 and the ring where B is located, X2 and the ring where B is located, and A means that X1 and the ring where B is located, X2 and the ring where B is located, and A are fused by sharing carbon atoms 3, 4, and 5; the relationship between X1 and the ring where B is located and F means that X1 and the ring where B is located and F are fused by sharing carbon atoms 1 and 2; and the relationship between X2 and the ring where B is located and E means that X2 and the ring where B is located and E are fused by sharing carbon atoms 6 and 7. Although the size of E and F shown in the structure shown in general formula (II) is inconsistent with the size of A, this is merely to illustrate that A, E, F, the ring where X1 is located and B, and the ring where X2 is located are fused, and the relative sizes of the rings are not limited.

[0319] It should be noted that, when A, E and F are selected from any one of a substituted aromatic ring, a substituted heteroaromatic ring and a substituted cycloalkane ring, the substituent may be linked to an adjacent substituent to form a substituted or unsubstituted ring. The "substituent" and "adjacent substituent" mentioned herein may be two substituents located on the same ring or two substituents located on two adjacent rings among A, E and F, and are not limited thereto.

[0320] In some examples, when A, E, and F are selected from any one of a substituted aromatic ring, a substituted heteroaromatic ring, and a substituted cycloalkane ring, the substituents are connected with adjacent substituents to form a substituted or unsubstituted ring containing heteroatoms such as O, N, and S.

[0321] It should be noted that when A, E or F is selected from any one of a substituted aromatic ring, a substituted heteroaromatic ring and a substituted cycloalkane ring, and / or R a 、R b or R c When the substituent is selected from any one of a substituted alkyl group, a substituted silyl group, a substituted alkoxy group, a substituted aryl group and a substituted heterocyclic group, the type and number of the substituent are not limited.

[0322] It is understood that when at least one of A, E, and F contains deuterium, guest material D is a deuterated material. Compared to a case where guest material D does not contain deuterium atoms, as previously described, firstly, the bond dissociation energy of guest material D can be increased, making the probability of guest material D being degraded by the energy of intermediates relatively lower. At the same time, the probability of guest material D undergoing side reactions can be reduced, thereby improving the stability of guest material D and the lifespan of light-emitting device 100 (e.g., first light-emitting device 101). Second, energy loss caused by molecular vibration of the guest material can be reduced, thereby improving the efficiency of light-emitting device 100 (e.g., first light-emitting device 101). Third, molecular vibration can be suppressed, narrowing the emission spectrum of guest material D, and resulting in relatively high color purity of light-emitting device 100 (e.g., first light-emitting device 101).

[0323] An exemplary structure of the guest material D represented by the general formula (II) is described below.

[0324] In some examples, when X1 and X2 are both N(R a ), and two R a When no deuterium is contained, the structural formula of the guest material D can be shown as follows.

[0325] In some examples, when X1 and X2 are both N(R a ), and two R a When both contain deuterium, the structural formula of the guest material D can be shown as follows.

[0326] In some examples, when X1 is N(R a ), R a Contains deuterium, and X2 is C(R b R c ), the structural formula of the guest material D can be shown as follows.

[0327] It should be noted that the above-listed structural formulas are examples of the structures of the guest material D and are not intended to limit the guest material D. Furthermore, (Dx) in the above-listed structural formulas is a synonym for each structural formula and is not part of the structural formula structure, where x is a positive integer.

[0328] In some embodiments, the substituent of at least one of A, E, and F comprises tert-butyl.

[0329] In related art, the tert-butyl group is the group left after removing the hydrogen atom from the methine group of the 2-methylpropane molecule. It has a tetrahedral structure. Therefore, when the tert-butyl group is used as a substituent, it has a good steric effect and spatial effect.

[0330] It is understood that when at least one of the substituents among A, E, and F includes a tert-butyl group, the structure represented by general formula (II) has a certain degree of stereoactivity, which improves the stereoactivity of the structure of the guest material D and reduces the planarity of the structure of the guest material D. Because the planarity of the material structure is low, the distance between molecules can be increased, the intermolecular forces can be reduced, and the ordered stacking of molecules can be reduced, resulting in relatively less quenching of excitons. Therefore, by configuring at least one of the substituents among A, E, and F to include a tert-butyl group, the quenching of excitons on the guest material D can be relatively reduced, and the exciton concentration on the guest material can be relatively high, thereby improving the efficiency of the light-emitting device 100 (e.g., the first light-emitting device 101).

[0331] It should be noted that, when at least one of A, E, and F contains deuterium and at least one of the substituents includes a tert-butyl group, the ring containing the deuterium substituent and the ring containing the tert-butyl substituent in A, E, and F may be the same ring or different rings, without limitation. Furthermore, when the substituent includes a tert-butyl group, some of the hydrogen atoms in the tert-butyl group may be replaced by deuterium, i.e., the tert-butyl group may be a deuterium-substituted tert-butyl group, without limitation.

[0332] The following describes an exemplary structure of the guest material D when, in the structure represented by general formula (II), at least one of the substituents among A, E, and F includes a tert-butyl group.

[0333] In some examples, when the substituent of E and the substituent of F both include tert-butyl groups, the structural formula of the guest material D can be as shown in (D-1), (D-2), and (D-3) above.

[0334] It should be noted that the structural formulas listed above are examples of the structure of the guest material D, and are not intended to limit the guest material D.

[0335] In some embodiments, when the guest material is a deuterated material, the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%.

[0336] The mass fraction of deuterium in the above-mentioned guest material refers to the ratio between the relative molecular mass of deuterium atoms in the structure of the guest material and the relative molecular mass of the guest material molecules.

[0337] It is understood that when the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%, the mass fraction of deuterium in the guest material is relatively high, that is, the guest material contains a relatively large number of deuterium atoms. As mentioned above, on the one hand, when the number of deuterium atoms in the guest material is relatively large, the bond dissociation energy and stability of the guest material can be increased, thereby improving the lifespan of the light-emitting device 100 (e.g., the first light-emitting device 101). At the same time, the molecular vibration of the guest material can be reduced, reducing the quantum efficiency loss caused by the molecular vibration of the guest material, thereby improving the efficiency of the light-emitting device 100 (e.g., the first light-emitting device 101). On the other hand, when the number of deuterium atoms in the guest material is relatively large, the molecular vibration can be suppressed, narrowing the emission spectrum of the guest material, and thus achieving relatively high color purity of the light-emitting device 100 (e.g., the first light-emitting device 101). On the other hand, when the guest material contains relatively more deuterium atoms, the energy required for the guest material to undergo side reactions is also relatively high. In this way, the probability of the guest material undergoing side reactions can be relatively low, thereby improving the stability of the guest material.

[0338] Exemplarily, the guest material D is selected from any one of the structures represented by general formula (II), and the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%.

[0339] For example, the mass fraction of deuterium in the guest material may be 0.1%, 1.0%, 3.0%, 5.0%, 7.0% or 8.5%, etc.

[0340] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (III).

[0341] Wherein, Z is selected from O, S, N (R d ) and C(R e R f ) in any one of the following. Wherein, O is oxygen, S is sulfur, N(R d ) is R d Substituted nitrogen, C(R e R f ) is R e With R f substituted carbon.

[0342] R d 、R e and R f are the same or different and are independently selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl.

[0343] L3 and L4 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group.

[0344] e and f are the same or different and are independently selected from any one of 1, 2, 3 and 4.

[0345] Ar3, Ar4, Ar5 and Ar6 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S. Wherein O is oxygen, S is sulfur, and N is nitrogen.

[0346] p and q are the same or different and are independently selected from any one of 0, 1 and 2; and the sum of p and q is greater than or equal to 1 and less than or equal to 2.

[0347] Regarding the structure shown in general formula (III), the following points need to be explained:

[0348] The description of L3 or L4 being a single bond herein may refer to the above description of L1 or L2 being a single bond; the description of aryl and heteroaryl groups herein may refer to the above description of aryl and heteroaryl groups; the description of arylene and heteroarylene groups herein may refer to the above description of arylene and heteroarylene groups, which will not be repeated here.

[0349] The aryl group of Cx refers to an aryl group having x carbon (C) atoms. Here, x is a positive integer, and the same applies to the following. For understanding other heteroaryl groups such as Cx, please refer to the above content and will not be repeated here.

[0350] The attachment position of L3 to the IIIA moiety in general formula (III) refers to the position at which L3 can attach to any of the 1', 2', 3', and 4' carbon atoms of the IIIA moiety that are substituted. The attachment position of deuterium (D) to the IIIA moiety and the attachment position of L4 to the IIIA moiety can be understood as described above and will not be further elaborated here. The attachment positions of any two of the e deuterium (D) atoms and the f deuterium (D) atoms to the IIIA moiety are different. Furthermore, when e is 4, p is 0; and when f is 4, q is 0.

[0351] When the sum of p and q is 1, the structure represented by the general formula (III) contains one triarylamine structure; when the sum of p and q is 2, the structure represented by the general formula (III) contains two triarylamine structures.

[0352] When R d 、R e or R f When L3 or L4 is selected from any one of substituted alkyl, substituted aryl and substituted heteroaryl, and / or Ar3, Ar4, Ar5 or Ar6 is selected from any one of substituted C6-C60 aryl and substituted C2-C60 heteroaryl, the type and number of the substituents are not limited here.

[0353] It is understood that when Z is oxygen, the IIIA portion has a dibenzofuran structure; when Z is sulfur, the IIIA portion has a dibenzothiophene structure; and when Z is nitrogen, the IIIA portion has a carbazole structure. When the IIIA portion has a dibenzofuran, dibenzothiophene, or carbazole structure, the carbon positions 1' to 8' and the position of Z are highly reactive. When chemical reactions occur at these positions, they may cause degradation of the first functional material. In the structure shown in the above general formula (III), e deuteriums (D) and f deuteriums (D) are connected to (e+f) of the carbon atoms 1' to 8', that is, multiple deuteriums replace hydrogen located at higher reaction active sites. In this way, the bond length can be shortened, the bond dissociation energy can be increased, and the molecular stability of the first functional material can be improved; at the same time, the probability of side reactions in the first functional material can be reduced, thereby improving the electrical stability of the first functional material, improving the electronic resistance of the first functional material, slowing down the degradation of the first functional material caused by electrons and excitons, improving the stability of the first functional material, and improving the life of the light-emitting device 100 (for example, the first light-emitting device 101).

[0354] Moreover, when the IIIA part is a dibenzofuran structure, a dibenzothiophene structure or a carbazole structure, the triplet energy level of the first functional material is relatively high, so that the difference between the triplet energy level of the first functional material and the triplet energy level of the main material is relatively large; in this way, after the holes and electrons recombine on the main material to form triplet excitons, the triplet excitons transferred from the main material to the first functional material are relatively small. In this way, the triplet excitons can be bound in the light-emitting layer 131 (for example, bound to the main material), the triplet exciton concentration in the light-emitting layer 131 can be increased, the TTA effect can be enhanced, and the TTA effect can be fully utilized to improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0355] When Z is carbon, the IIIA part is a fluorene or spirofluorene structure. In the fluorene or spirofluorene structure, sp3 carbon (i.e., Z) is an unstable part in the molecule and may cause defects due to chemical reactions. In the structure shown in the above general formula (III), e deuteriums (D) and f deuteriums (D) are connected to (e+f) of the carbons 1' to 8' to form a multi-deuterium-substituted fluorene or spirofluorene structure. On the one hand, it can improve the molecular stability and electrical stability of the first functional material, enhance the electronic resistance of the first functional material, and increase the life of the light-emitting device 100 (for example, the first light-emitting device 101). On the other hand, the zero point energy (Zero Point Energy), that is, the energy of the ground state, can be reduced, and the deuterium-carbon bonding length is shorter than the hydrogen-carbon bonding length, which can reduce the molecular core volume (Molecular hardcore volume), thereby reducing the electronic polarizability (Electroical polarizability). This property can reduce the crystallinity of the film, that is, the amorphous state. The amorphous state reduces grain boundaries through isotropic and homogeneous properties, allowing charges to flow quickly and improving the hole mobility of the first functional material.

[0356] An exemplary structure of the first functional material G1 represented by the general formula (III) is described below.

[0357] In some examples, when Z is oxygen, the structural formula of the first functional material G1 can be as shown below.

[0358] In some examples, when Z is sulfur, the structural formula of the first functional material G1 can be as shown below.

[0359] In some examples, when Z is nitrogen substituted with a phenyl group, the structural formula of the first functional material G1 can be as shown below.

[0360] In some examples, when Z is carbon substituted with a methyl group, the structural formula of the first functional material G1 can be as shown below.

[0361] It should be noted that the above-listed structural formulas are examples of the structure of the first functional material G1 and are not intended to limit the first functional material G1. Furthermore, (G1-x) in the above structural formulas is a synonym for each structural formula and is not part of the structural formula structure, where x is a positive integer.

[0362] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (III-A).

[0363] wherein g and h are the same or different and are independently selected from any one of 0, 1, 2 and 3.

[0364] When carbon atoms 3' and 6' in the structure represented by general formula (III) are connected to deuterium, the structure represented by general formula (III) can be transformed into the structure represented by general formula (III-A).

[0365] It can be understood that in the IIIA portion of the structure shown in general formula (III), the reaction activity of carbons 3' and 6' is relatively high compared to carbons 1', 2', 4', 5', 7', and 8'. When a chemical reaction occurs at the position of carbons 3' and 6', it may cause degradation of the first functional material. In the structure shown in the above general formula (III-A), deuterium replaces the hydrogen connected to carbons 3' and 6'. This can shorten the bond length and increase the bond dissociation energy. At the same time, it can reduce the probability of side reactions in the first functional material and improve the molecular stability of the first functional material. In this way, the electrical stability of the first functional material can be improved, the electronic resistance of the first functional material can be improved, the degradation of the first functional material caused by electrons and excitons can be slowed down, the stability of the first functional material can be improved, and the life of the light-emitting device 100 (for example, the first light-emitting device 101) can be improved.

[0366] An exemplary structure of the first functional material G in the structure represented by the general formula (III-A) is described below.

[0367] In some examples, when Z is oxygen, the structural formula of the first functional material G1 can be as shown in (G1-1) to (G1-6) above.

[0368] In some examples, when Z is sulfur, the structural formula of the first functional material G1 can be as shown in (G1-8) to (G1-11) above.

[0369] In some examples, when Z is a carbon substituted with a methyl group, the structural formula of the first functional material G1 can be as shown in (G1-14) and (G1-15) above.

[0370] It should be noted that the structural formula listed above is an example of the structure of the first functional material G1, and does not limit the first functional material G1.

[0371] In some embodiments, the first functional material is selected from any one of the structures represented by the following general formula (IV).

[0372] Wherein, L5 is selected from any one of a single bond and a substituted or unsubstituted C6-C60 arylene group.

[0373] Ar7 and Ar8 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S. Wherein N is nitrogen, O is oxygen, and S is sulfur.

[0374] R9 and R 10 the same or different, and independently selected from any one of hydrogen, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C6-C60 aryl and substituted or unsubstituted C2-C60 heteroaryl; or may be connected with adjacent substituents to form a substituted or unsubstituted ring; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O and S.

[0375] m and n are the same or different and are independently selected from any one of 1, 2, 3 and 4.

[0376] At least one R9 is deuterium.

[0377] At least one R 10 For deuterium.

[0378] The description of L5 as a single bond herein may refer to the above description of L1 as a single bond; the description of the aryl group of Cx, the alkyl group of Cx, etc. herein may refer to the above description of the aryl group of Cx, the alkyl group of Cx; the description of the aryl group and the heteroaryl group herein may refer to the above description of the aryl group and the heteroaryl group; the description of the arylene group and the heteroarylene group herein may refer to the above description of the arylene group and the heteroarylene group, which will not be repeated here.

[0379] When L5 is selected from substituted C6-C60 arylene groups, and / or Ar7 or Ar8 is selected from any one of substituted C6-C60 aryl groups and substituted C2-C60 heteroaryl groups, and / or R9 or R 10 When the substituent is selected from any one of a substituted C1-C60 alkyl group, a substituted C3-C60 cycloalkyl group, a substituted C2-C60 alkenyl group, a substituted C6-C60 aryl group, and a substituted C2-C60 heteroaryl group, the type and number of the substituent are not limited herein.

[0380] It is understood that the structure shown in general formula (IV) contains carbazolyl groups, and the carbon positions 1" to 8" in the carbazolyl groups have high reactivity. When chemical reactions occur at these positions, the first functional material may be degraded. In the structure shown in general formula (IV), m deuterium R9 and n R 10 Connected to (m+n) of carbons 1" to 8", and at least one R9 is deuterium, at least one R 10 It is deuterium, that is, multiple deuteriums replace hydrogen located at higher reaction active sites, so that the bond length can be shortened, the bond dissociation energy can be increased, and the molecular stability of the first functional material can be improved; at the same time, the probability of side reactions in the first functional material can be reduced, so that the electrical stability of the first functional material can be improved, the electronic resistance of the first functional material can be improved, and the degradation of the first functional material caused by electrons and excitons can be slowed down, so that the stability of the first functional material is improved, and the life of the light-emitting device 100 (for example, the first light-emitting device 101) is improved.

[0381] Moreover, since the structure shown in general formula (IV) contains a carbazole group, the triplet energy level of the first functional material is relatively high, and the difference between the triplet energy level of the first functional material and the triplet energy level of the host material is relatively large; in this way, after the holes and electrons recombine to form triplet excitons on the host material, the triplet excitons transferred from the host material to the first functional material are relatively small. In this way, the triplet excitons can be bound in the light-emitting layer 131 (for example, bound to the host material), the concentration of triplet excitons in the light-emitting layer 131 can be increased, the TTA effect can be enhanced, and the TTA effect can be fully utilized to improve the efficiency of the light-emitting device 100 (for example, the first light-emitting device 101).

[0382] An exemplary structure of the first functional material G1 represented by the general formula (IV) is described below.

[0383] In some examples, when Ar7 and Ar8 include biphenyl groups, the structural formula of the first functional material G1 can be as shown below.

[0384] In some examples, when Ar7 and Ar8 include naphthyl groups, the structural formula of the first functional material G1 can be as shown below.

[0385] As shown in the first functional material of the above structural formulas (G1-16) to (G1-21), it can be seen that in the structure shown in the general formula (VI), the deuterium substitution position can be located at the positions of carbon No. 3” and carbon No. 6”. Compared with carbon No. 1”, 2”, 4”, 5”, 7”, and 8”, the reactivity of carbon No. 3” and carbon No. 6” is relatively high. By setting the positions of carbon No. 3” and carbon No. 6” for deuteration, the molecular stability of the positions of carbon No. 3” and carbon No. 6” can be improved, making the stability of the first functional material relatively higher, and thus improving the life of the light-emitting device 100 (for example, the first light-emitting device 101).

[0386] It should be noted that the above-listed structural formulas are examples of the structure of the first functional material G1 and are not intended to limit the first functional material G1. Furthermore, (G1-x) in the above structural formulas is a synonym for each structural formula and is not part of the structural formula structure, where x is a positive integer.

[0387] In some embodiments, when the first functional material is a deuterated material, the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

[0388] The mass fraction of deuterium in the first functional material refers to the ratio between the relative molecular mass of deuterium atoms in the structure of the first functional material and the relative molecular mass of the first functional material molecules.

[0389] It is understood that when the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%, the mass fraction of deuterium in the first functional material is relatively high, that is, the first functional material contains a relatively large number of deuterium atoms. As mentioned above, when the number of deuterium atoms in the first functional material is relatively large, the bond dissociation energy and stability of the first functional material can be increased, the electrical stability of the first functional material can be increased, the electronic resistance of the first functional material can be improved, the degradation of the first functional material caused by electrons and excitons can be slowed down, the stability of the first functional material can be improved, and the life of the light-emitting device 100 (for example, the first light-emitting device 101) can be increased. Moreover, when the first functional material contains a relatively large number of deuterium atoms, the energy required for the first functional material to undergo side reactions is also relatively high. In this way, the probability of the first functional material undergoing side reactions can be relatively low, and the stability of the first functional material can be improved.

[0390] In some examples, the first functional material is selected from any one of the structures represented by formula (III), and the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

[0391] In other examples, the first functional material is selected from any one of the structures represented by general formula (III-A), and the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

[0392] In some other examples, the first functional material is selected from any one of the structures represented by formula (IV), and the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

[0393] For example, the mass fraction of deuterium in the guest material may be 0.15%, 1.00%, 2.00%, 3.00%, 4.00% or 5.50%, etc.

[0394] In order to objectively evaluate the technical effects of the embodiments of the present disclosure, the technical solutions provided by the present disclosure are described in detail and exemplarily through the following experimental examples and comparative examples. According to different device structure types, the following experimental examples and comparative examples are divided into the first group of experimental examples, the second group of experimental examples, and the third group of experimental examples.

[0395] The first group of test cases

[0396] The following embodiments and comparative examples use different materials to make the light-emitting layer 131 and the electron blocking layer 1323 of the first light-emitting device 101, and compare the voltage, current efficiency, and device life of the first light-emitting device 101.

[0397] In the following comparative examples and embodiments, the structure of the first light-emitting device 101 and the test conditions of the first light-emitting device 101 are the same.

[0398] The first light emitting device 101 is a single-layer light emitting device, and its structure is shown in FIG6 . The method for preparing a display panel including the first light emitting device 101 includes: using a substrate 210 (glass substrate) provided with a pixel defining layer 221 and an anode 11 as a backplane, and placing the backplane in a vacuum chamber of a vacuum evaporation device, and evacuating the vacuum chamber to 1×10 -5 Pa~1×10 -6After Pa, the hole injection layer 1321, the hole transport layer 1322, the electron blocking layer 1323, the light emitting layer 131, the hole blocking layer 1333, the electron transport layer 1332, the electron injection layer 1331, the cathode 12, and the covering layer 15 are sequentially formed on the backplane. Before use, the backplane is first ultrasonically treated in a detergent, then rinsed with deionized water, and then ultrasonically treated in an acetone-ethanol mixed solvent to remove oil, and then dried in a clean environment until the water and solvent are removed.

[0399] It should be noted that the thicknesses of the hole injection layer 1321, hole transport layer 1322, electron blocking layer 1323, light-emitting layer 131, hole blocking layer 1333, electron transport layer 1332, electron injection layer 1331, cathode 12, and covering layer 15 in the embodiment and the comparative example are the same, namely 10 nm, 100 nm, 10 nm, 20 nm, 5 nm, 30 nm, 1 nm, 13 nm, and 60 nm, respectively.

[0400] The materials of the anode 11 , the hole injection layer 1321 , the hole transport layer 1322 , the hole blocking layer 1333 , the electron transport layer 1332 , the electron injection layer 1331 , and the cathode 12 in the embodiment and the comparative example are the same. Among them, the material of the anode 11 is indium tin oxide (ITO); the material of the hole injection layer 1321 is a mixed material obtained by mixing a hole transport material (structure as shown in the aforementioned structural formula (HTL)) and a hole injection material (structure as shown in the following formula (HIL)) in a mass ratio of 98:2; the structure of the material of the hole transport layer 1322 is as shown in the aforementioned structural formula (HTL); the structure of the material of the hole blocking layer 1333 is shown in the following formula (HBL); the material of the electron transport layer 1332 is a mixed material obtained by mixing a first electron transport material (structure as shown in the following formula (ETL)) and a second electron transport material (structure as shown in the following formula (LiQ)) in a mass ratio of 1:1; the material of the electron injection layer 1331 is ytterbium; the material of the cathode 12 is a magnesium-silver alloy (Mg:Ag=1:9).

[0401] The materials of the electron blocking layer 1323 and the light-emitting layer 131 in the embodiments and comparative examples are different, wherein the materials of the electron blocking layer 1323 in the comparative examples and some embodiments include a comparative first functional material, the structure of which is shown in the following formula (R-G1); the materials of the light-emitting layer 131 in the comparative examples and some embodiments include a comparative host material and a comparative guest material, the structure of the comparative host material is shown in the following formula (RH); the structure of the comparative guest material is shown in the following formula (RD).

[0402] It should be noted that (HIL), (HBL), (ETL), (LiQ), (RH), (RD), and (R-G1) in the above structural formulas are aliases for each structural formula and are not part of the structural formula structure.

[0403] The materials of the light-emitting layer 131 and the electron blocking layer 1323 of the first light-emitting device 101 of the embodiment and the comparative example are described below respectively.

[0404] In Example 1, the light-emitting layer 131 includes a host material H and a guest material D. The structural formula of the host material H is shown in (H-4), and the structural formula of the guest material D is shown in (D-4). Furthermore, the mass ratio of the host material H to the guest material D is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (G1-13).

[0405] In Example 2, the light-emitting layer 131 includes a host material H and a guest material D. The structural formula of the host material H is shown in (H-5), and the structural formula of the guest material D is shown in (D-6). Furthermore, the mass ratio of the host material H to the guest material D is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (G1-7).

[0406] In Example 3, the light-emitting layer 131 includes a host material H and a guest material D. The structural formula of the host material H is shown in (H-4), and the structural formula of the guest material D is shown in (D-4). Furthermore, the mass ratio of the host material H to the guest material D is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (G1-18).

[0407] In Example 4, the light-emitting layer 131 includes a host material H and a guest material D. The structural formula of the host material H is shown in (H-5), and the structural formula of the guest material D is shown in (D-6). Furthermore, the mass ratio of the host material H to the guest material D is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (G1-20).

[0408] In Example 5, the light-emitting layer 131 includes a host material H and a guest material D. The structural formula of the host material H is shown in (H-5), and the structural formula of the guest material D is shown in (D-4). Furthermore, the mass ratio of the host material H to the guest material D is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (R-G1).

[0409] In Example 6, the light-emitting layer 131 includes a comparative host material and a comparative guest material. The structural formula of the comparative host material is shown in (RH), and the structural formula of the comparative guest material is shown in (RD). Furthermore, the mass ratio of the comparative host material to the comparative guest material is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (G1-13).

[0410] In Example 7, the light-emitting layer 131 includes a host material H and a comparative guest material. The structural formula of the host material H is shown in (H-4); the structural formula of the comparative guest material is shown in (RD). Furthermore, the mass ratio of the host material H to the comparative guest material is 97:3. The structural formula of the material of the electron blocking layer 1323 is shown in (R-G1).

[0411] In Example 8, light-emitting layer 131 includes a comparative host material and a guest material D. The structural formula of the comparative host material is shown in (RH), and the structural formula of the guest material D is shown in (D-4). Furthermore, the mass ratio of the comparative host material to the guest material D is 97:3. The structural formula of the material of electron blocking layer 1323 is shown in (R-G1).

[0412] In Example 9, light-emitting layer 131 includes a comparative host material and guest material D. The comparative host material has the structural formula shown in (RH), and the guest material D has the structural formula shown in (D-4). Furthermore, the mass ratio of the comparative host material to the guest material D is 97:3. The structural formula of the material of electron blocking layer 1323 is shown in (G1-18).

[0413] In Comparative Example 1, light-emitting layer 131 includes a comparative host material and a comparative guest material. The structural formula of the comparative host material is shown in (RH), and the structural formula of the comparative guest material is shown in (RD). Furthermore, the mass ratio of the comparative host material to the comparative guest material is 97:3. The structural formula of the material of electron blocking layer 1323 is shown in (R-G1).

[0414] In order to more clearly describe the differences in the structural formulas of the main material, guest material and the material of the electron blocking layer 1323 used in the embodiments and comparative examples, the following Table 1 is used to more clearly show the structural formulas of the main material, guest material and the material of the electron blocking layer 1323 used in the embodiments and comparative examples.

[0415] Table 1

[0416] It should be noted that "Ax" in Table 1 refers to the corresponding structural formula Ax. For example, the sub-grid corresponding to host material H in Example 1 is "H-4," which means that the structural formula of host material H in the light-emitting layer 131 of Example 1 is shown as (H-4). The structural formulas represented by Hx, Dx, G1-x (x is a positive integer), RH, RD, and R-G1 are as described above and are not repeated here.

[0417] In this set of experimental examples, Gaussian 09 software was used to simulate the overlap ratio of the HOMO state density of the material of the electron blocking layer 1323 with the HOMO state density of the material of the hole transport layer 1322 (the structure of which is shown in the aforementioned structural formula (HTL)), and the overlap ratio of the HOMO state density of the material of the electron blocking layer 1323 with the HOMO state density of the host material. The results are shown in Table 2. The simulation calculation process includes: after performing a deposition simulation on hundreds to thousands of molecules (for example, 500 molecules), the HOMO energy of each material is calculated through quantum mechanics, and the HOMO state density of each material is obtained based on this. The distribution difference of the HOMO state density of the material of the electron blocking layer 1323 and the material of the hole transport layer 1322 (the structure of which is shown in the aforementioned structural formula (HTL)) is then compared, as well as the distribution difference of the HOMO state density of the material of the electron blocking layer 1323 and the HOMO state density of the host material. The overlap ratio is then converted into a percentage to obtain the HOMO state density overlap ratio.

[0418] Table 2

[0419] As shown in Table 2, the overlap ratio of the HOMO density of states between the first functional materials having structures such as those represented by formulas (G1-13), (G1-7), (G1-18), and (G1-20) and the host materials having structures such as those represented by formulas (H-4) and (H-5) is between 12% and 32%, indicating a high overlap ratio. The overlap ratio of the HOMO density of states between the first functional materials having structures such as those represented by formulas (G1-13), (G1-7), (G1-18), and (G1-20) and the second functional material having the structure represented by the general formula (HTL) (i.e., the material of the electron transport layer 1322) is between 55% and 74%, indicating a high overlap ratio.

[0420] In this set of experimental examples, the hole reorganization energy and electron reorganization energy of the above-mentioned host materials were calculated using simulation software, and the absolute value of the difference between the electron reorganization energy and the hole reorganization energy was calculated. The results are shown in Table 3.

[0421] Table 3

[0422] As shown in Table 3, the differences between the electron reorganization energy and the hole reorganization energy of the host materials with structures such as Formula (H-4) and Formula (H-5) are 0.02 eV and 0.05 eV, respectively, both less than 0.1 eV.

[0423] In this set of test examples, the thermal decomposition temperature (Td) (i.e., the temperature corresponding to a 5% weight loss) of the host material, guest material, and first functional material was measured using a thermogravimetric analyzer (TGA). The test was conducted under a nitrogen atmosphere over a temperature range of room temperature to 600°C at a heating rate of 10°C / min. Furthermore, the dipole moments (Debye) of the host material, guest material, and first functional material were calculated using Gaussian 09 software. The results of the thermal decomposition temperature (Td) and dipole moment are shown in Table 4.

[0424] Table 4

[0425] As can be seen from Table 4, the thermal decomposition temperatures of the main materials with structures such as those shown in formulas (H-4) and (H-5), the guest materials with structures such as those shown in formulas (D-4) and (D-6), and the first functional materials with structures such as those shown in formulas (G1-13), (G1-7), (G1-18) and (G1-20) are in the range of 371°C to 439°C, which are all relatively high, indicating that the above materials have good thermal stability.

[0426] It can be seen from Table 4 that the dipole moments of the main materials with structures such as those shown in formula (H-4) and formula (H-5), the guest materials with structures such as those shown in formula (D-4) and formula (D-6), and the first functional materials with structures such as those shown in formula (G1-13), (G1-7), (G1-18) and (G1-20) are in the range of 0.08D to 0.22D, all of which are greater than 0D, indicating that the molecules of the above materials are asymmetric.

[0427] Based on the above materials, the first light-emitting device 101 of Examples 1 to 9 and Comparative Example 1 was tested for voltage (V), current efficiency (cd / A), and device life. The voltage (V), current efficiency (cd / A), and device life data were based on Comparative Example 1. The test results are shown in Table 5 below. Device life is characterized by the parameter LT95.

[0428] Table 5

[0429] As can be seen from Table 5, compared with Comparative Example 1, the device lifespans of Examples 1 to 4 are in the range of 111% to 152%, which are all relatively high. This is because in the first light-emitting devices 101 of Examples 1 to 4, the host material H, the guest material D, and the material of the electron blocking layer 1323 (i.e., the first functional material) are all deuterated materials, while in Comparative Example 1, the comparative host material RH, the comparative guest material RD, and the comparative first functional material R-G1 are all materials that do not contain deuterium atoms. Since deuterated materials have relatively high bond dissociation energy, the stability of the material can be improved. When the host material H, the guest material D, and the material of the electron blocking layer 1323 (i.e., the first functional material) are all deuterated materials, the material of the first light-emitting device 101 contains relatively more deuterium atoms, and the stability of the three materials is improved. Moreover, under the synergistic effect of the three deuterated materials, the first light-emitting device 101 exhibits a relatively excellent device lifespan.

[0430] Comparing Examples 1 to 4 with Comparative Example 1, as shown in Table 5, the device efficiencies of Examples 1 to 4 range from 106% to 119%, all relatively high. This is because in the first light-emitting devices 101 of Examples 1 to 4, the host material H, guest material D, and the material of the electron blocking layer 1323 (i.e., the first functional material) are all deuterated materials, while in Comparative Example 1, the comparative host material RH, comparative guest material RD, and comparative first functional material R-G1 are all materials that do not contain deuterium atoms. When the host material H and guest material D are deuterated materials, molecular vibrations are relatively minimal, resulting in relatively low quantum efficiency losses caused by molecular vibrations of the host material H and guest material D, and thus relatively high efficiency of the first light-emitting device 101.

[0431] Compared with Comparative Example 1, Example 5, Example 7, and Example 8, as shown in Table 5, have relatively long device lifespans. This is because in the first light-emitting device 101 of Examples 5, 7, and 8, the host material H and / or the guest material D are both deuterated materials, while in Comparative Example 1, the comparative host material RH and the comparative guest material RD are both materials that do not contain deuterium atoms. The host material or comparative host material is the site where high-energy excitons are generated by recombination, and the guest material or comparative guest material is the material that receives the energy transferred by the host material or the comparative host material and radiates light. Because deuterated materials have relatively high bond dissociation energies, the electrical stability of the material can be improved. When the host material H and / or the guest material D are both deuterated materials, the host material H and / or the guest material D have relatively high electrical stability, which can improve tolerance to high-energy excitons and high-energy intermediates of the TTA effect, resulting in the first light-emitting device 101 exhibiting a relatively excellent device lifespan.

[0432] Compared with Comparative Example 1, Example 6 and Example 9, as shown in Table 5, the device lifespan of Example 6 and Example 9 is relatively high. This is because in the first light-emitting device 101 of Example 6 and Example 9, the material of the electron blocking layer 1323 (i.e., the first functional material) is a deuterated material, while in Comparative Example 1, the material of the electron blocking layer 1323 (i.e., the first functional material for comparison) is a material that does not contain deuterium atoms. Since the deuterated material has a relatively high bond dissociation energy, the electrical stability of the material can be improved. When the material of the electron blocking layer 1323 is a deuterated material, the material of the electron blocking layer 1323 has a relatively high electrical stability, which can improve the tolerance to carriers (electrons or holes) and excitons, so that the first light-emitting device 101 exhibits a relatively excellent device lifespan.

[0433] As shown in Table 5, the device efficiencies of Examples 6 and 9 are relatively high compared to Comparative Example 1. This is because the structure of the material (i.e., the first functional material) of the electron blocking layer 1323 in the first light-emitting devices 101 of Examples 6 and 9 is selected from the structure represented by Formula (III) or Formula (IV), while in Comparative Example 1, the material (i.e., the first functional material) of the electron blocking layer 1323 does not conform to the structure represented by Formula (III) or Formula (IV). Since the structure represented by general formula (III) or general formula (IV) contains a carbazole group, a dibenzofuran group, a dibenzothiophene group, a fluorene group or a spirofluorene group, the triplet energy level of the first functional material can be made relatively high, and the difference between the triplet energy level of the first functional material and the triplet energy level of the host material can be made relatively large; in this way, after the holes and electrons recombine on the host material to form triplet excitons, the triplet excitons transferred from the host material to the first functional material are relatively small. In this way, the triplet excitons can be bound in the light-emitting layer 131 (for example, bound to the host material), the triplet exciton concentration in the light-emitting layer 131 can be increased, the TTA effect can be enhanced, the TTA effect can be fully utilized, and the efficiency of the first light-emitting device 101 can be improved.

[0434] As can be seen from the above embodiments and comparative examples, the present disclosure can improve the efficiency of the stacked light-emitting device 100 (for example, the first light-emitting device 101) and the device life of the stacked light-emitting device 100 (for example, the first light-emitting device 101) by setting the overlap rate of the HOMO state density of the first functional material and the HOMO state density of the second functional material to be greater than 0% and less than or equal to 90%. Moreover, by setting the host material H to be selected from any one of the structures represented by general formula (I), the guest material D to be selected from any one of the structures represented by general formula (II), and the first functional material G1 to be selected from any one of the structures represented by general formula (III) or general formula (IV), the efficiency of the single-layer light-emitting device 100 (for example, the first light-emitting device 101) can be further improved, and the device life of the single-layer light-emitting device 100 (for example, the first light-emitting device 101) can be improved.

[0435] The second group of test cases

[0436] The following embodiments and comparative examples use different materials to make the light-emitting layer 131 and the electron blocking layer 1323 of the first light-emitting device 101, and compare the voltage, current efficiency, and device life of the first light-emitting device 101.

[0437] In the following comparative examples and embodiments, the structure of the first light-emitting device 101 and the test conditions of the first light-emitting device 101 are the same.

[0438] The first light-emitting device 101 is a stacked light-emitting device, and its structure is shown in FIG16 . Specifically, the first light-emitting device 101 includes a stacked anode 11, a hole injection layer 1321, a hole transport layer 1322a, an electron blocking layer 1323a, a light-emitting layer 131B-a, a hole blocking layer 1333a, an electron generating layer 141, a hole generating layer 142, a hole transport layer 1322b, an electron blocking layer 1323b, a light-emitting layer 131B-b, a hole blocking layer 1333b, an electron transport layer 1332, and a cathode 12. Among them, the hole injection layer 1321, the hole transport layer 1322a, the electron blocking layer 1323a, the light-emitting layer 131B-a, and the hole blocking layer 1333a located on the side close to the anode 11 constitute the first light-emitting unit 13, and the hole transport layer 1322b, the electron blocking layer 1323b, the light-emitting layer 131B-b, the hole blocking layer 1333b, the electron transport layer 1332, and the electron injection layer 1331 located on the side close to the cathode 12 constitute the second light-emitting unit 13.

[0439] The method for preparing a display panel including the first light emitting device 101 includes: using a substrate 210 (glass substrate) provided with a pixel defining layer 221 and an anode 11 as a backplane, placing the backplane in a vacuum chamber of a vacuum evaporation device, and evacuating the vacuum chamber to 1×10 -5 Pa~1×10-6 After Pa, the materials of the hole injection layer 1321, the hole transport layer 1322a, the electron blocking layer 1323a, the light emitting layer 131B-a, the hole blocking layer 1333a, the electron generating layer 141, the hole generating layer 142, the hole transport layer 1322b, the electron blocking layer 1323b, the light emitting layer 131B-b, the hole blocking layer 1333b, the electron transport layer 1332 ... electron generating layer 141 The materials of the sub-injection layer 1331 and the materials of the cathode 12 are used to sequentially form on the back plate a hole injection layer 1321, a hole transport layer 1322a, an electron blocking layer 1323a, a light-emitting layer 131B-a, a hole blocking layer 1333a, an electron generating layer 141, a hole generating layer 142, a hole transport layer 1322b, an electron blocking layer 1323b, a light-emitting layer 131B-b, a hole blocking layer 1333b, an electron transport layer 1332, an electron injection layer 1331, and a cathode 12. Prior to use, the back plate is first ultrasonically treated in a detergent, then rinsed with deionized water, and then ultrasonically treated in an acetone-ethanol mixed solvent to remove oil, and then dried in a clean environment until the water and solvent are removed.

[0440] It should be noted that the thicknesses of the hole injection layer 1321, hole transport layer 1322a, electron blocking layer 1323a, light-emitting layer 131B-a, hole blocking layer 1333a, electron generating layer 141, hole generating layer 142, hole transport layer 1322b, electron blocking layer 1323b, light-emitting layer 131B-b, hole blocking layer 1333b, electron transport layer 1332, electron injection layer 1331 and cathode 12 in the embodiment and the comparative example are all the same, namely, 10 nm, 19 nm, 5 nm, 15 nm, 5 nm, 18 nm, 9 nm, 19 nm, 5 nm, 15 nm, 5 nm, 35 nm, 1 nm and 15 nm, respectively.

[0441] The materials of the hole injection layer 1321, hole transport layer 1322a, hole blocking layer 1333a, electron generating layer 141, hole generating layer 142, hole transport layer 1322b, hole blocking layer 1333b, electron transport layer 1332, electron injection layer 1331 and cathode 12 in the embodiment and the comparative example are the same. The material of the anode 11 is indium tin oxide (ITO); the material of the hole injection layer 1321 is a mixed material obtained by mixing a hole transport material (the structure of which is shown in the aforementioned structural formula (HTL)) and a hole injection material (the structure of which is shown in the aforementioned structural formula (HIL)) in a mass ratio of 95:5; the materials of the hole transport layer 1322a and the hole transport layer 1322b are the same, and their structures are shown in the aforementioned structural formula (HTL); the materials of the hole blocking layer 1333a and the hole blocking layer 1333b are the same, and their structures are shown in the aforementioned structural formula (HBL); the material of the electron transport layer 1332 is a first electron transport material (the structure of which is shown in the aforementioned structural formula (ET) L) as shown in the above formula) and a second electron transport material (the structure is shown in the above structural formula (LiQ)) mixed in a mass ratio of 1:1; the material of the electron injection layer 1331 is ytterbium; the electron generation layer 141 is a mixed material obtained by mixing an electron generating material (the structure is shown in the following formula (N-CGL)) and ytterbium in a mass ratio of 99:1; the material of the hole generation layer 142 is a mixed material obtained by mixing a hole generating material (the structure is the same as that shown in the above structural formula (HTL)) and a hole injection material (the structure is shown in the above structural formula (HIL)) in a mass ratio of 95:5; the material of the cathode 12 is a magnesium-silver alloy (Mg:Ag=1:9).

[0442] It should be noted that (N-CGL) in the above structural formula is a synonym for the structural formula and is not a part of the structural formula.

[0443] The materials of the electron blocking layer 1323a, the light-emitting layer 131B-a, the electron blocking layer 1323b, and the light-emitting layer 131B-b of the first light-emitting device 101 of the embodiment and the comparative example are described below.

[0444] In Example 10, light-emitting layers 131B-a and 131B-b include a host material H and a guest material D. The structural formula of host material H is shown in (H-4), and the structural formula of guest material D is shown in (D-4). Furthermore, the mass ratio of host material H to guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (G1-13).

[0445] In Example 11, light-emitting layers 131B-a and 131B-b include a host material H and a guest material D. The structural formula of host material H is shown in (H-5), and the structural formula of guest material D is shown in (D-6). Furthermore, the mass ratio of host material H to guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (G1-7).

[0446] In Example 12, light-emitting layers 131B-a and 131B-b include a host material H and a guest material D. The structural formula of host material H is shown in (H-4), and the structural formula of guest material D is shown in (D-4). Furthermore, the mass ratio of host material H to guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (G1-18).

[0447] In Example 13, light-emitting layers 131B-a and 131B-b include a host material H and a guest material D. The structural formula of host material H is shown in (H-5), and the structural formula of guest material D is shown in (D-6). Furthermore, the mass ratio of host material H to guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (G1-20).

[0448] In Example 14, light-emitting layers 131B-a and 131B-b include a host material H and a guest material D. The structural formula of host material H is shown in (H-5), and the structural formula of guest material D is shown in (D-4). Furthermore, the mass ratio of host material H to guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (R-G1).

[0449] In Example 15, light-emitting layers 131B-a and 131B-b include a comparative host material and a comparative guest material. The structural formula of the comparative host material is shown in (RH), and the structural formula of the comparative guest material is shown in (RD). Furthermore, the mass ratio of the comparative host material to the comparative guest material is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (G1-13).

[0450] In Example 16, light-emitting layers 131B-a and 131B-b include a host material H and a comparative guest material. The structural formula of host material H is shown in (H-4); the structural formula of comparative guest material is shown in (RD). Furthermore, the mass ratio of host material H to comparative guest material is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (R-G1).

[0451] In Example 17, light-emitting layers 131B-a and 131B-b include a comparative host material and a guest material D. The structural formula of the comparative host material is shown in (RH), and the structural formula of the guest material D is shown in (D-4). Furthermore, the mass ratio of the comparative host material to the guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (R-G1).

[0452] In Example 18, light-emitting layers 131B-a and 131B-b include a comparative host material and a guest material D. The structural formula of the comparative host material is shown in (RH), and the structural formula of the guest material D is shown in (D-4). Furthermore, the mass ratio of the comparative host material to the guest material D is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (G1-18).

[0453] In Comparative Example 2, light-emitting layers 131B-a and 131B-b include a comparative host material and a comparative guest material. The structural formula of the comparative host material is shown in (RH), and the structural formula of the comparative guest material is shown in (RD). Furthermore, the mass ratio of the comparative host material to the comparative guest material is 97:3. The structural formulas of the materials of electron blocking layers 1323a and 1323b are shown in (R-G1).

[0454] In order to more clearly describe the differences in the structural formulas of the main material, guest material and the material of the electron blocking layer 1323 used in the embodiments and comparative examples, the following Table 6 is used to more clearly show the structural formulas of the main material, guest material and the material of the electron blocking layer 1323 used in the embodiments and comparative examples.

[0455] Table 6

[0456] It should be noted that "Ax" in Table 6 refers to the corresponding structural formula Ax. For example, the subcell corresponding to host material H in Example 10 is "H-4," which means that the structural formula of host material H in light-emitting layers 131B-a and 131B-b of Example 10 is shown as (H-4). The structural formulas represented by Hx, Dx, G1-x (x is a positive integer), RH, RD, and R-G1 are as described above and are not repeated here.

[0457] Regarding the overlap rate of the HOMO state density of the above-mentioned host material H, guest material D, and first functional material G1, the absolute value of the difference between the electron reorganization energy and the hole reorganization energy, the thermal decomposition temperature Td, and the dipole moment data, please refer to the first group of experimental examples and will not be repeated here.

[0458] Based on the above materials, the first light-emitting devices 101 of Examples 10 to 18 and Comparative Example 2 were tested for voltage (V), current efficiency (cd / A), and device lifespan. The voltage (V), current efficiency (cd / A), and device lifespan data were compared with Comparative Example 1. The test results are shown in Table 7 below. Device lifespan is characterized by the parameter LT95.

[0459] Table 7

[0460] As shown in Table 7, compared to Comparative Example 2, the device lifetimes of Examples 10 to 13 are relatively high, ranging from 129.8% to 141.9%. This is because in the first light-emitting devices 101 of Examples 10 to 13, the host material H and guest material D of the light-emitting layers 131B-a and 131B-b, as well as the materials of the electron blocking layers 1323a and 1323b (i.e., the first functional materials) are all deuterated materials, while in Comparative Example 2, the comparative host material RH and comparative guest material RD of the light-emitting layers 131B-a and 131B-b, as well as the comparative first functional material R-G1 of the electron blocking layers 1323a and 1323b, are all materials that do not contain deuterium atoms. Because deuterated materials have relatively high bond dissociation energies, they can improve material stability. When the main material H and guest material D of the light-emitting layer 131B-a and the light-emitting layer 131B-b, as well as the materials of the electron blocking layer 1323a and the electron blocking layer 1323b (i.e., the first functional material) are all deuterated materials, the material of the first light-emitting device 101 contains relatively more deuterium atoms, and the stability of the three materials is improved. Moreover, under the synergistic effect of the three deuterated materials, the first light-emitting device 101 can exhibit a relatively excellent device life.

[0461] As shown in Table 7, the device efficiencies of Examples 10 to 13 are relatively high, ranging from 103.6% to 106.2%. This is because the host material H and guest material D of the light-emitting layers 131B-a and 131B-b, as well as the materials of the electron blocking layers 1323a and 1323b (i.e., the first functional materials) in the first light-emitting devices 101 of Examples 10 to 13 are all deuterated materials, while in Comparative Example 2, the comparative host material RH and comparative guest material RD of the light-emitting layers 131B-a and 131B-b, as well as the comparative first functional material R-G1 of the electron blocking layers 1323a and 1323b, are all materials that do not contain deuterium atoms. When the host material H and the guest material D are deuterated materials, the molecular vibration is relatively small, so that the quantum efficiency loss caused by the molecular vibration of the host material H and the guest material D is relatively small, and the efficiency of the first light-emitting device 101 is relatively high.

[0462] As shown in Table 7, compared with Comparative Example 2, Examples 14, 16, and 17 have relatively long device lifespans. This is because in the first light-emitting devices 101 of Examples 14, 16, and 17, the host material H and / or the guest material D of the light-emitting layer 131B-a and the light-emitting layer 131B-b are all deuterated materials, while in Comparative Example 1, the comparative host material RH and the comparative guest material RD of the light-emitting layer 131B-a and the light-emitting layer 131B-b are both materials that do not contain deuterium atoms. The host material or the comparative host material is the location where high-energy excitons are generated by recombination, and the guest material or the comparative guest material is the material that receives the energy transferred by the host material or the comparative host material and radiates light. Since the deuterated material has a relatively high bond dissociation energy, the electrical stability of the material can be improved. When the main material H and / or the guest material D of the light-emitting layer 131B-a and the light-emitting layer 131B-b are both deuterated materials, the main material H and / or the guest material D have relatively high electrical stability, which can improve the tolerance to high-energy excitons and high-energy intermediates of the TTA effect, so that the first light-emitting device 101 exhibits a relatively excellent device life.

[0463] Compared with Comparative Example 2, Example 15 and Example 18, as shown in Table 7, the device lifespan of Example 15 and Example 18 is relatively high. This is because in the first light-emitting device 101 of Example 15 and Example 18, the material of the electron blocking layer 1323a and the electron blocking layer 1323b (i.e., the first functional material) is a deuterated material, while in Comparative Example 1, the material of the electron blocking layer 1323a and the electron blocking layer 1323b (i.e., the first functional material for comparison) is a material that does not contain deuterium atoms. Since the deuterated material has a relatively high bond dissociation energy, the electrical stability of the material can be improved. When the material of the electron blocking layer 1323a and the electron blocking layer 1323b is a deuterated material, the material of the two electron blocking layers has a relatively high electrical stability, which can improve the tolerance to carriers (electrons or holes) and excitons, so that the first light-emitting device 101 exhibits a relatively excellent device lifespan.

[0464] As shown in Table 7, the device efficiencies of Examples 15 and 18 are relatively high compared to Comparative Example 2. This is because the materials (i.e., the first functional materials) of the electron blocking layers 1323a and 1323b in the first light-emitting devices 101 of Examples 15 and 18 are selected from the structures represented by Formula (III) or Formula (IV), while in Comparative Example 1, the materials (i.e., the comparative first functional materials) of the electron blocking layers 1323a and 1323b do not conform to the structures represented by Formula (III) or Formula (IV). Since the structure represented by general formula (III) or general formula (IV) contains a carbazole group, a dibenzofuran group, a dibenzothiophene group, a fluorene group or a spirofluorene group, the triplet energy level of the first functional material can be made relatively high, and the difference between the triplet energy level of the first functional material and the triplet energy level of the host material can be made relatively large; in this way, after the holes and electrons recombine on the host material to form triplet excitons, the triplet excitons transferred from the host material to the first functional material are relatively small. In this way, the triplet excitons can be bound in the light-emitting layer 131 (for example, bound to the host material), the triplet exciton concentration in the light-emitting layer 131 can be increased, the TTA effect can be enhanced, the TTA effect can be fully utilized, and the efficiency of the first light-emitting device 101 can be improved.

[0465] As can be seen from the above embodiments and comparative examples, the present disclosure can improve the efficiency of the stacked light-emitting device 100 (e.g., the first light-emitting device 101) and the device life of the stacked light-emitting device 100 (e.g., the first light-emitting device 101) by configuring the overlap rate of the HOMO state density of the first functional material and the HOMO state density of the second functional material to be greater than 0% and less than or equal to 90%. Moreover, by configuring the host material H to be selected from any of the structures represented by general formula (I), the guest material D to be selected from any of the structures represented by general formula (II), and the first functional material G1 to be selected from any of the structures represented by general formula (III) or general formula (IV), the efficiency of the stacked light-emitting device 100 (e.g., the first light-emitting device 101) and the device life of the stacked light-emitting device 100 (e.g., the first light-emitting device 101) can be further improved.

[0466] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A light emitting device, comprising: A cathode and an anode disposed opposite to each other, and at least one light emitting unit disposed between the cathode and the anode; The light-emitting unit comprises: a light-emitting layer and a first type of functional layer arranged on a side of the light-emitting layer close to the anode; the first type of functional layer comprises a first sub-functional layer and a second sub-functional layer; the material of the first sub-functional layer comprises a first functional material, and the material of the second sub-functional layer comprises a second functional material; The overlap rate of the HOMO state density of the first functional material and the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%.

2. The light emitting device according to claim 1, wherein: The first sub-functional layer is in contact with the light-emitting layer; the material of the light-emitting layer includes a host material; The overlap rate of the HOMO state density of the first functional material and the HOMO state density of the main material is greater than 0% and less than or equal to 90%.

3. The light emitting device according to claim 2, wherein: The material of the light-emitting layer further includes a guest material; at least one of the host material, the guest material and the first functional material is a deuterated material.

4. The light emitting device according to claim 2 or 3, wherein: The absolute value of the difference between the electron reorganization energy and the hole reorganization energy of the host material is less than or equal to 0.1 eV; and / or, The hole mobility of the host material is greater than the electron mobility of the host material.

5. The light emitting device according to any one of claims 1 to 4, wherein: The dipole moment of the first functional material is greater than 0D.

6. The light emitting device according to any one of claims 1 to 5, wherein: The lowest of the bond dissociation energies of the first functional material in the ground state is greater than or equal to 2.40 eV; and / or, The lowest bond dissociation energy of the first functional material in an anionic state is greater than or equal to 1.0 eV.

7. The light emitting device according to any one of claims 3 to 6, wherein: The lowest of the bond dissociation energies of the host material in the ground state is greater than or equal to 1.50 eV; and / or, The lowest of the bond dissociation energies of the guest material in the ground state is greater than or equal to 1.50 eV.

8. The light emitting device according to any one of claims 3 to 7, wherein: The triplet energy level of the host material is smaller than the triplet energy level of the guest material; and / or The singlet energy level of the host material is greater than the singlet energy level of the guest material.

9. The light emitting device according to any one of claims 2 to 8, wherein: The light-emitting unit further comprises: a second type of functional layer disposed on a side of the light-emitting layer close to the cathode; the second type of functional layer comprises a third sub-functional layer, the third sub-functional layer is in contact with the light-emitting layer; the material of the third sub-functional layer comprises a third functional material; Wherein, the triplet energy level of the host material is smaller than the triplet energy level of the third functional material; and / or, The triplet energy level of the host material is smaller than the triplet energy level of the first functional material.

10. The light emitting device according to any one of claims 2 to 9, wherein: The main material is selected from any one of the structures shown in the following general formula (I); wherein R1, R2, R3, R4, R5, R6, R7 and R8 are the same or different and are independently selected from any one of hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted diarylamino, substituted or unsubstituted siloxane and substituted or unsubstituted silyl; L1 and L2 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group; Ar1 and Ar2 are the same or different and are independently selected from substituted or unsubstituted aryl groups; At least one of R1, R2, R3, R4, R5, R6, R7, R8, L1, L2, Ar1 and Ar2 contains deuterium.

11. The light emitting device according to any one of claims 2 to 10, wherein: In the case where the host material is a deuterated material, the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%.

12. The light emitting device according to any one of claims 3 to 11, wherein: The guest material is selected from any one of the structures shown in the following general formula (II); wherein A, E and F are the same or different and are independently selected from any one of a substituted or unsubstituted aromatic ring, a substituted or unsubstituted heteroaromatic ring and a substituted or unsubstituted cycloalkane ring; in the case where A, E and F are selected from any one of a substituted aromatic ring, a substituted heteroaromatic ring and a substituted cycloalkane ring, the substituent may be linked to an adjacent substituent to form a substituted or unsubstituted ring; X1 and X2 are the same or different and are independently selected from O, N(R a ) and C(R b R c ) R a , R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted silyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl and substituted or unsubstituted heterocyclic group; At least one of A, E and F contains deuterium.

13. The light emitting device according to claim 12, wherein: Among A, E and F, at least one of the substituents includes a tert-butyl group.

14. The light emitting device according to any one of claims 3 to 13, wherein: In the case where the guest material is a deuterated material, the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%.

15. The light emitting device according to any one of claims 1 to 14, wherein: The first functional material is selected from any one of the structures shown in the following general formula (III); Wherein, Z is selected from O, S, N (R d ) and C(R e R f ) R d , R e and R f are the same or different and are independently selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl; L3 and L4 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group; e and f are the same or different and are independently selected from any one of 1, 2, 3 and 4; Ar3, Ar4, Ar5 and Ar6 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S; p and q are the same or different and are independently selected from any one of 0, 1 and 2; and the sum of p and q is greater than or equal to 1 and less than or equal to 2.

16. The light emitting device according to claim 15, wherein: The first functional material is selected from any one of the structures shown in the following general formula (III-A); wherein g and h are the same or different and are independently selected from any one of 0, 1, 2 and 3.

17. The light emitting device according to any one of claims 1 to 14, wherein: The first functional material is selected from any one of the structures shown in the following general formula (IV); Wherein, L5 is selected from any one of a single bond and a substituted or unsubstituted C6-C60 arylene group; Ar7 and Ar8 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S; R9 and R 10 The same or different, independently selected from any one of hydrogen, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C6-C60 aryl and substituted or unsubstituted C2-C60 heteroaryl; or may be connected with adjacent substituents to form a substituted or unsubstituted ring; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O and S; m and n are the same or different and are independently selected from any one of 1, 2, 3 and 4; At least one R9 is deuterium; At least one R 10 For deuterium.

18. The light emitting device according to any one of claims 1 to 17, wherein: In the case where the first functional material is a deuterated material, the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

19. The light emitting device according to any one of claims 1 to 18, wherein: The light emitting device comprises at least two light emitting units, and the at least two light emitting units are stacked; The light emitting device further comprises a charge generating layer located between two adjacent light emitting units; the charge generating layer comprises a hole generating layer and an electron generating layer which are stacked; the electron generating layer is closer to the anode than the hole generating layer.

20. The light emitting device according to any one of claims 1 to 19, wherein: The structural formula of the second functional material is as follows:

21. The light emitting device according to any one of claims 1 to 20, wherein: The light emitting device is configured to emit light of a first wavelength, and the light of the first wavelength is blue light.

22. A display panel, wherein: comprising a plurality of light emitting devices according to any one of claims 1 to 21; It also includes: a plurality of pixel driving circuits, wherein the pixel driving circuits are electrically connected to the light emitting devices and are used to drive the light emitting devices to emit light.

23. A display panel, comprising: substrate; A plurality of light emitting devices are disposed on the substrate and arranged along a first direction, wherein the first direction is parallel to the plane where the substrate is located; The plurality of light emitting devices include at least one first light emitting device, at least one second light emitting device, and at least one third light emitting device, wherein the first light emitting device is configured to emit blue light; The second light emitting device is configured to emit green light; The third light emitting device is configured to emit red light; Each of the plurality of light emitting devices comprises a cathode and an anode arranged opposite to each other, and a at least one light-emitting unit between the cathode and the anode; the light-emitting unit comprises a light-emitting layer; the number of light-emitting units included in each of the plurality of light-emitting devices is n, where n is a positive integer greater than or equal to 1; The thickness of the light-emitting layer of the Nth light-emitting unit of the third light-emitting device is greater than the thickness of the light-emitting layer of the Nth light-emitting unit of the second light-emitting device; the thickness of the light-emitting layer of the Nth light-emitting unit of the second light-emitting device is greater than the thickness of the light-emitting layer of the Nth light-emitting unit of the first light-emitting device, wherein N is a positive integer less than or equal to n.

24. The display panel according to claim 23, wherein: A difference between a thickness of a light-emitting layer of an N-th light-emitting unit of the third light-emitting device and a thickness of a light-emitting layer of an N-th light-emitting unit of the first light-emitting device is a first thickness difference; A difference between a thickness of a light-emitting layer of an N-th light-emitting unit of the second light-emitting device and a thickness of a light-emitting layer of an N-th light-emitting unit of the first light-emitting device is a second thickness difference; A difference between a thickness of a light-emitting layer of an Nth light-emitting unit of the third light-emitting device and a thickness of a light-emitting layer of an Nth light-emitting unit of the second light-emitting device is a third thickness difference; Wherein, a ratio between the first thickness difference and the second thickness difference is greater than or equal to 1.5 and less than or equal to 2; A ratio between the third thickness difference and the second thickness difference is greater than or equal to 1 and less than or equal to 1.

5.

25. The display panel according to claim 23 or 24, wherein: The light-emitting unit further comprises a first type of functional layer disposed on a side of the light-emitting layer close to the anode; the first type of functional layer comprises a first sub-functional layer in contact with the light-emitting layer; The difference between the thickness of the first subfunctional layer of the Nth light-emitting unit of the third light-emitting device and the thickness of the first subfunctional layer of the Nth light-emitting unit of the first light-emitting device is a fourth thickness difference; the difference between the thickness of the first subfunctional layer of the Nth light-emitting unit of the second light-emitting device and the thickness of the first subfunctional layer of the Nth light-emitting unit of the first light-emitting device is a fifth thickness difference; A ratio between the fourth thickness difference and the fifth thickness difference is greater than or equal to 1.1 and less than or equal to 1.

5.

26. The display panel according to claim 25, wherein: The light-emitting unit also includes a second type of functional layer arranged on a side of the light-emitting layer close to the cathode; a ratio between a thickness of the first type of functional layer and a thickness of the second type of functional layer is greater than or equal to 1 and less than or equal to 5.

27. The display panel according to any one of claims 23 to 26, wherein: The material of the light-emitting layer includes a guest material, and the guest material is configured to emit light of a set wavelength; The relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is greater than or equal to 650 and less than or equal to 1300; and / or, The relative molecular weight of the guest material of the light-emitting layer of the second light-emitting device is greater than or equal to 700 and less than or equal to 1400; and / or, The relative molecular weight of the guest material of the light-emitting layer of the third light-emitting device is greater than or equal to 700 and less than or equal to 1500.

28. The display panel according to claim 27, wherein: The absolute value of the difference between the relative molecular weight of the guest material of the light-emitting layer of the third light-emitting device and the relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is less than or equal to 600; and / or, An absolute value of a difference between a relative molecular weight of a guest material in the light-emitting layer of the second light-emitting device and a relative molecular weight of a guest material in the light-emitting layer of the first light-emitting device is less than or equal to 500.

29. The display panel according to claim 27 or 28, wherein: The difference between the relative molecular weight of the guest material of the light-emitting layer of the third light-emitting device and the relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is a first relative molecular weight difference; The difference between the relative molecular weight of the guest material of the light-emitting layer of the second light-emitting device and the relative molecular weight of the guest material of the light-emitting layer of the first light-emitting device is a second relative molecular weight difference; The ratio of the absolute value of the first relative molecular weight difference to the absolute value of the second relative molecular weight difference is greater than or equal to 0.5 and less than or equal to 6.

30. The display panel according to any one of claims 25 to 29, wherein: The optical path of the light in the light-emitting layer of the light-emitting unit close to the anode of the first light-emitting device and the first type of functional layer is the first optical path; the optical path of the light in the light-emitting layer of the light-emitting unit close to the anode of the second light-emitting device and the first type of functional layer is the second optical path; the optical path of the light in the light-emitting layer of the light-emitting unit close to the anode of the third light-emitting device and the first type of functional layer is the third optical path; Among them, the ratio between the third optical path and the second optical path is greater than or equal to 1.1 and less than or equal to 1.25; the ratio between the third optical path and the first optical path is greater than or equal to 1.25 and less than or equal to 1.45; the ratio between the second optical path and the first optical path is greater than or equal to 1.05 and less than or equal to 1.

25.

31. The display panel according to any one of claims 23 to 30, wherein: The light emitting device comprises a first light emitting unit and a second light emitting unit; the first light emitting unit is closer to the anode than the second light emitting unit; A ratio of a thickness of the light-emitting layer of the first light-emitting unit to a thickness of the light-emitting layer of the second light-emitting unit is greater than or equal to 0.8 and less than or equal to 1.

5.

32. The display panel according to claim 31, wherein: In the case where the light-emitting unit includes a first type of functional layer and a second type of functional layer, the first type of functional layer further includes a second sub-functional layer and a fourth sub-functional layer, and the fourth sub-functional layer, the second sub-functional layer and the first sub-functional layer are sequentially arranged in a direction away from the anode; the second type of functional layer includes a third sub-functional layer, a fifth sub-functional layer and a sixth sub-functional layer; the sixth sub-functional layer, the fifth sub-functional layer and the third sub-functional layer are sequentially arranged in a direction away from the cathode; Among them, the sum of the thickness of the second sub-functional layer of the second light-emitting unit and the thickness of the fifth sub-functional layer is the first thickness sum, and the sum of the thickness of the second sub-functional layer of the first light-emitting unit and the thickness of the fifth sub-functional layer is the second thickness sum; the ratio between the first thickness sum and the second thickness sum is greater than or equal to 2 and less than or equal to 4.

33. The display panel according to claim 32, wherein: The sum of the thickness of the first sub-functional layer and the thickness of the second sub-functional layer of the second light-emitting unit is the third thickness sum, and the sum of the thickness of the first sub-functional layer and the thickness of the second sub-functional layer of the first light-emitting unit is the fourth thickness sum; the ratio of the third thickness sum to the fourth thickness sum is greater than or equal to 2 and less than or equal to 5.

34. The display panel according to claim 32 or 33, wherein: The sum of the thickness of the third sub-functional layer and the thickness of the fifth sub-functional layer of the second light-emitting unit is the fifth thickness sum, and the sum of the thickness of the third sub-functional layer and the thickness of the fifth sub-functional layer of the first light-emitting unit is the sixth thickness sum; the ratio of the fifth thickness sum to the sixth thickness sum is greater than or equal to 1.5 and less than or equal to 3.

35. The display panel according to any one of claims 25 to 34, wherein: In the case where the first type of functional layer further includes a second sub-functional layer, the material of the light-emitting layer includes a host material and a guest material; the material of the first sub-functional layer includes a first functional material, and the material of the second sub-functional layer includes a second functional material; wherein the overlap rate of the HOMO state density of the first functional material and the HOMO state density of the second functional material is greater than 0% and less than or equal to 90%; and / or, The overlap rate of the HOMO state density of the first functional material and the HOMO state density of the main material is greater than 0% and less than or equal to 90%.

36. The display panel according to claim 35, wherein: At least one of the host material, the guest material and the first functional material is a deuterated material.

37. The display panel according to claim 35 or 36, wherein: The absolute value of the difference between the electron reorganization energy and the hole reorganization energy of the host material is less than or equal to 0.1 eV; and / or, The hole mobility of the host material is greater than the electron mobility of the host material.

38. The display panel according to any one of claims 35 to 37, wherein: The dipole moment of the first functional material is greater than 0D.

39. The display panel according to any one of claims 35 to 38, wherein: The lowest of the bond dissociation energies of the first functional material in the ground state is greater than or equal to 2.40 eV; and / or, The lowest bond dissociation energy of the first functional material in an anionic state is greater than or equal to 1.0 eV.

40. The display panel according to any one of claims 35 to 39, wherein: The lowest of the bond dissociation energies of the host material in the ground state is greater than or equal to 1.50 eV; and / or, The lowest of the bond dissociation energies of the guest material in the ground state is greater than or equal to 1.50 eV.

41. The display panel according to any one of claims 35 to 40, wherein: The triplet energy level of the host material is smaller than the triplet energy level of the guest material; and / or The singlet energy level of the host material is greater than the singlet energy level of the guest material.

42. The display panel according to any one of claims 35 to 41, wherein: When the light-emitting unit further includes a third sub-functional layer, the third sub-functional layer is in contact with the light-emitting layer; and the material of the third sub-functional layer includes a third functional material; Wherein, the triplet energy level of the host material is smaller than the triplet energy level of the third functional material; and / or, The triplet energy level of the host material is smaller than the triplet energy level of the first functional material.

43. The display panel according to any one of claims 35 to 42, wherein: The main material is selected from any one of the structures shown in the following general formula (I); wherein R1, R2, R3, R4, R5, R6, R7 and R8 are the same or different and are independently selected from any one of hydrogen, deuterium, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted aryloxy, substituted or unsubstituted diarylamino, substituted or unsubstituted siloxane and substituted or unsubstituted silyl; L1 and L2 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group; Ar1 and Ar2 are the same or different and are independently selected from substituted or unsubstituted aryl groups; At least one of R1, R2, R3, R4, R5, R6, R7, R8, L1, L2, Ar1 and Ar2 contains deuterium.

44. The display panel according to any one of claims 35 to 43, wherein: In the case where the host material is a deuterated material, the mass fraction of deuterium in the host material is greater than or equal to 1.0% and less than or equal to 4.9%.

45. The display panel according to any one of claims 27 to 44, wherein: The guest material is selected from any one of the structures shown in the following general formula (II); wherein A, E and F are the same or different and are independently selected from any one of a substituted or unsubstituted aromatic ring, a substituted or unsubstituted heteroaromatic ring and a substituted or unsubstituted cycloalkane ring; in the case where A, E and F are selected from any one of a substituted aromatic ring, a substituted heteroaromatic ring and a substituted cycloalkane ring, the substituent may be linked to an adjacent substituent to form a substituted or unsubstituted ring; X1 and X2 are the same or different and are independently selected from O, N(R a ) and C(R b R c ) R a , R b and R c are the same or different and are independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted silyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl and substituted or unsubstituted heterocyclic group; At least one of A, E and F contains deuterium.

46. ​​The display panel according to claim 45, wherein: Among A, E and F, at least one of the substituents includes a tert-butyl group.

47. The display panel according to any one of claims 27 to 46, wherein: In the case where the guest material is a deuterated material, the mass fraction of deuterium in the guest material is greater than or equal to 0.1% and less than or equal to 8.5%.

48. The display panel according to any one of claims 35 to 47, wherein: The first functional material is selected from any one of the structures shown in the following general formula (III); Wherein, Z is selected from O, S, N (R d ) and C(R e R f ) R d , R e and R f are the same or different and are independently selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl; L3 and L4 are the same or different and are independently selected from any one of a single bond, a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group; e and f are the same or different and are independently selected from any one of 1, 2, 3 and 4; Ar3, Ar4, Ar5 and Ar6 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom, and the heteroatom includes N, O and S; p and q are the same or different and are independently selected from any one of 0, 1 and 2; and the sum of p and q is greater than or equal to 1 and less than or equal to 2.

49. The display panel according to claim 48, wherein: The first functional material is selected from any one of the structures shown in the following general formula (III-A); wherein g and h are the same or different and are independently selected from any one of 0, 1, 2 and 3.

50. The display panel according to any one of claims 35 to 47, wherein: The first functional material is selected from any one of the structures shown in the following general formula (IV); Wherein, L5 is selected from any one of a single bond and a substituted or unsubstituted C6-C60 arylene group; Ar7 and Ar8 are the same or different and are independently selected from any one of a substituted or unsubstituted C6-C60 aryl group and a substituted or unsubstituted C2-C60 heteroaryl group; the C2-C60 heteroaryl group includes at least one heteroatom. The atoms include N, O, and S; R9 and R 10 The same or different, independently selected from any one of hydrogen, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C6-C60 aryl and substituted or unsubstituted C2-C60 heteroaryl; or may be connected with adjacent substituents to form a substituted or unsubstituted ring; the C2-C60 heteroaryl includes at least one heteroatom, and the heteroatom includes N, O and S; m and n are the same or different and are independently selected from any one of 1, 2, 3 and 4; At least one R9 is deuterium; At least one R 10 For deuterium.

51. The display panel according to any one of claims 35 to 50, wherein: In the case where the first functional material is a deuterated material, the mass fraction of deuterium in the first functional material is greater than or equal to 0.15% and less than or equal to 5.50%.

52. The display panel according to any one of claims 23 to 51, wherein: The light emitting device comprises at least two light emitting units, and the at least two light emitting units are stacked; The light emitting device further comprises a charge generating layer located between two adjacent light emitting units; the charge generating layer comprises a hole generating layer and an electron generating layer which are stacked; the electron generating layer is closer to the anode than the hole generating layer.

53. The display panel according to any one of claims 35 to 52, wherein: The structural formula of the second functional material is as follows:

54. The display panel according to any one of claims 35 to 53, wherein: The host material is the host material of the light-emitting layer of the first light-emitting device; the guest material is the guest material of the light-emitting layer of the first light-emitting device; the first functional material is the material of the first sub-functional layer of the first light-emitting device; the second functional material is the material of the second sub-functional layer of the first light-emitting device; In the case where the light-emitting unit further includes a third sub-functional layer, the third functional material is the material of the third sub-functional layer of the first light-emitting device.

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