Light emitting device, light emitting substrate, and light emitting apparatus

Abstract

The application discloses a light-emitting device, a light-emitting substrate and a light-emitting device, and relates to the technical field of display. The light-emitting device comprises a first electrode, a second electrode arranged opposite to the first electrode, and a plurality of light-emitting layers arranged in a stack between the first electrode and the second electrode, wherein the plurality of light-emitting layers comprises at least one first light-emitting layer and at least one second light-emitting layer; the first light-emitting layer comprises a first light-emitting material configured to emit a first light under the driving of current or voltage; the second light-emitting layer comprises a second light-emitting material configured to emit a second light under the driving of current or voltage; the light-emitting efficiency of the first light-emitting material is greater than the light-emitting efficiency of the second light-emitting material; and the brightness conversion rate of the first light for photoexciting a color conversion material is less than the brightness conversion rate of the second light for photoexciting the color conversion material.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular, to a light emitting device, a light emitting substrate and a light emitting apparatus. BACKGROUND

[0002] Organic Light Emitting Diode (OLED) is an active light emitting device, which has the advantages of self-illumination, wide viewing angle, fast response time, high luminous efficiency, low working voltage and simple process, and is known as the next generation of "star" light emitting device. SUMMARY

[0003] The present disclosure provides a light emitting device, comprising:

[0004] a first electrode;

[0005] a second electrode, and the first electrode is oppositely arranged; and

[0006] a plurality of light emitting layers, which are stacked between the first electrode and the second electrode, and the plurality of light emitting layers comprise at least one first light emitting layer and at least one second light emitting layer;

[0007] wherein,

[0008] the first light emitting layer comprises a first light emitting material, which is configured to emit a first light under the driving of current or voltage;

[0009] the second light emitting layer comprises a second light emitting material, which is configured to emit a second light under the driving of current or voltage;

[0010] the light emitting efficiency of the first light emitting material is greater than the light emitting efficiency of the second light emitting material; and

[0011] the luminance conversion rate of the first light to photo-excitation of a color conversion material is less than the luminance conversion rate of the second light to photo-excitation of the color conversion material.

[0012] In an optional implementation, the triplet energy level of the first light emitting material is lower than the triplet energy level of the second light emitting material.

[0013] In an optional implementation, the difference between the triplet energy level of the second light emitting material and the triplet energy level of the first light emitting material is greater than or equal to 0.1 eV and less than or equal to 0.3 eV.

[0014] In an optional implementation, the molecular mass of the first light emitting material is greater than the molecular mass of the second light emitting material.

[0015] In an optional implementation, the peak wavelength of the first light is greater than the peak wavelength of the second light.

[0016] In an optional implementation, the peak wavelength of the first light is greater than or equal to 460 nm and less than or equal to 470 nm; and the peak wavelength of the second light is greater than or equal to 450 nm and less than or equal to 460 nm.

[0017] In an optional implementation, the full width at half maximum of the first light and the second light are both less than or equal to 20 nm.

[0018] In an optional implementation, the first electrode is a reflective electrode, the second electrode is a transmissive electrode or a semi-transmissive electrode; and the second light-emitting layer is located on the side of the first light-emitting layer close to the first electrode.

[0019] In an optional implementation, the plurality of light-emitting layers comprises at least two first light-emitting layers, and the at least one second light-emitting layer is located on the side of the at least two first light-emitting layers close to the first electrode.

[0020] In an optional implementation, the light-emitting device further comprises at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, a charge generation layer, an electron transport layer and an electron injection layer which are stacked between the first electrode and the second electrode.

[0021] In an optional implementation, the first electrode is an anode, the second electrode is a cathode, and the light-emitting device further comprises:

[0022] a hole injection layer, a first hole transport layer and a first electron blocking layer which are stacked between the first electrode and the plurality of light-emitting layers, the hole injection layer being located close to the first electrode;

[0023] a first hole blocking layer, a first charge generation layer, a second hole transport layer and a second electron blocking layer which are stacked between two adjacent light-emitting layers, the first hole blocking layer being located close to the first electrode;

[0024] a second hole blocking layer, an electron transport layer and an electron injection layer which are stacked between the plurality of light-emitting layers and the second electrode, the electron injection layer being located close to the second electrode; and

[0025] a light extraction layer provided on the side of the second electrode away from the first electrode.

[0026] In an optional implementation, the first light-emitting material and the second light-emitting material each comprise at least one of an organic electroluminescent material and a quantum dot.

[0027] The present disclosure provides a light-emitting substrate, comprising:

[0028] a first substrate;

[0029] a plurality of switching elements disposed on the first substrate; and

[0030] a plurality of light-emitting devices as claimed in any one of the preceding claims connected to the switching elements.

[0031] In an alternative implementation, the light-emitting substrate further comprises:

[0032] a thin film encapsulation layer disposed on a side of the light-emitting device facing away from the first substrate, a projection of the thin film encapsulation layer on the first substrate covering the first substrate.

[0033] In an alternative implementation, the light-emitting substrate further comprises:

[0034] a color conversion layer disposed on a light-emitting side of the light-emitting device, for receiving incident light and emitting light of a different color from the incident light, the incident light being light emitted by the light-emitting device.

[0035] In an alternative implementation, the incident light is blue light, the light-emitting substrate comprises a plurality of pixels, each of the pixels comprising a red sub-pixel, a blue sub-pixel and a green sub-pixel; the color conversion layer comprises at least one of:

[0036] a first color conversion pattern located at the red sub-pixel, for emitting red light under excitation of the incident light;

[0037] a second color conversion pattern located at the green sub-pixel, for emitting green light under excitation of the incident light; and

[0038] a transmission pattern located at the blue sub-pixel, for transmitting the incident light.

[0039] In an alternative implementation, the color conversion layer comprises a color conversion material, the color conversion material comprising at least one of: quantum dots, rare earth materials, fluorescent materials and organic dyes.

[0040] In an alternative implementation, the light-emitting substrate further comprises:

[0041] a color filter layer disposed on a light-emitting side of the color conversion layer, comprising:

[0042] a first color filter pattern located at the red sub-pixel, for transmitting red light incident on the first color filter pattern;

[0043] a second color filter pattern located at the green sub-pixel and configured to transmit green light incident on the second color filter pattern; and

[0044] a third color filter pattern located at the blue sub-pixel and configured to transmit blue light incident on the third color filter pattern.

[0045] In an optional implementation, the light-emitting substrate further includes:

[0046] a second substrate disposed on a side of the color filter layer opposite to the color conversion layer; and

[0047] a filling layer disposed between the thin-film encapsulation layer and the color conversion layer and configured to bond the thin-film encapsulation layer and the color conversion layer, wherein the thin-film encapsulation layer is located between the light-emitting device and the color conversion layer.

[0048] The present disclosure provides a light-emitting device, including:

[0049] the light-emitting substrate as claimed in any one of the preceding claims;

[0050] a driving integrated circuit configured to provide a driving signal to the light-emitting substrate; and

[0051] a power supply circuit configured to provide a power supply to the light-emitting substrate.

[0052] The above description is only a summary of the technical solutions of the present disclosure. In order to enable one skilled in the art to better understand the technical means of the present disclosure, the contents of the specification can be implemented, and in order to make the above and other purposes, features and advantages of the present disclosure more obvious and easy to understand, the specific embodiments of the present disclosure are described below. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the related art, the drawings needed to be used in the embodiments or related art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present disclosure, and those skilled in the art can also obtain other drawings according to these drawings without creative labor. It should be noted that the proportions in the drawings are only for illustration and do not represent the actual proportions.

[0054] Figure 1 schematically shows a cross-sectional structure schematic diagram of a first light-emitting device provided by the present disclosure;

[0055] Figure 2 schematically shows a cross-sectional structure schematic diagram of a second light-emitting device provided by the present disclosure;

[0056] Figure 3A cross-sectional structure schematic diagram of a third light emitting device provided by the present disclosure is shown schematically;

[0057] Figure 4 A cross-sectional structure schematic diagram of a fourth light emitting device provided by the present disclosure is shown schematically;

[0058] Figure 5 A cross-sectional structure schematic diagram of a fifth light emitting device provided by the present disclosure is shown schematically;

[0059] Figure 6 A cross-sectional structure schematic diagram of a sixth light emitting device provided by the present disclosure is shown schematically;

[0060] Figure 7 Spectral test results of the first light emitting material and the second light emitting material are shown schematically;

[0061] Figure 8 Performance test results of several light emitting devices are shown schematically;

[0062] Figure 9 A cross-sectional structure schematic diagram of a first light emitting substrate provided by the present disclosure is shown schematically;

[0063] Figure 10 A cross-sectional structure schematic diagram of a second light emitting substrate provided by the present disclosure is shown schematically;

[0064] Figure 11 A planar structure schematic diagram of a light emitting substrate provided by the present disclosure is shown schematically;

[0065] Figure 12 A cross-sectional structure schematic diagram of a first color conversion pattern example is shown schematically;

[0066] Figure 13 A cross-sectional structure schematic diagram of a second color conversion pattern example is shown schematically;

[0067] Figure 14 A cross-sectional structure schematic diagram of a transmission pattern example is shown schematically. DETAILED DESCRIPTION

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are some but not all of the embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0069] The present disclosure provides a light emitting device, which is described with reference to Figures 1 to 6 A cross-sectional structure schematic diagram of a light emitting device provided by the present disclosure is shown schematically. As shown, the light emitting device includes a first electrode 11, a second electrode 12 disposed opposite to the first electrode 11, and a plurality of light emitting layers 13 stacked between the first electrode 11 and the second electrode 12, the plurality of light emitting layers 13 including at least one first light emitting layer 131 and at least one second light emitting layer 132. Figures 1 to 6

[0070] The first light emitting layer 131 includes a first light emitting material configured to emit a first light under driving of a current or a voltage, and the second light emitting layer 132 includes a second light emitting material configured to emit a second light under driving of the current or the voltage.

[0071] The first light emitting material has a light emitting efficiency greater than a light emitting efficiency of the second light emitting material, and the first light has a luminance conversion rate for photoexciting a color conversion material less than a luminance conversion rate of the second light for photoexciting the color conversion material.

[0072] The first electrode 11 and the second electrode 12 are configured to provide the current or the voltage to the plurality of light emitting layers 13.

[0073] The light emitting efficiency of the first light emitting material refers to a ratio between a luminous flux of the light emitted by the first light emitting material (i.e., the first light) and an electric power consumed by the first light emitting material. The light emitting efficiency of the second light emitting material refers to a ratio between a luminous flux of the light emitted by the second light emitting material (i.e., the second light) and an electric power consumed by the second light emitting material.

[0074] The luminance conversion rate of the first light for photoexciting the color conversion material refers to a ratio between a luminance of the light emitted by the color conversion material and a luminance of the first light when the first light irradiates the color conversion material, i.e., a first luminance conversion rate.

[0075] The luminance conversion rate of the second light for photoexciting the color conversion material refers to a ratio between a luminance of the light emitted by the color conversion material and a luminance of the second light when the second light irradiates the color conversion material, i.e., a second luminance conversion rate.

[0076] When the first light and the second light irradiate the same color conversion material, respectively, the first luminance conversion rate is less than the second luminance conversion rate.

[0077] ​In the light-emitting device provided in the present disclosure, at least two of the plurality of light-emitting layers 13 adopt different light-emitting materials, for example, the first light-emitting layer 131 adopts a first light-emitting material, and the second light-emitting layer 132 adopts a second light-emitting material. Since the first light-emitting material has a higher light-emitting efficiency, and the second light-emitting material has a higher brightness conversion rate, when the color conversion material is irradiated by the light-emitting device provided in the present disclosure, both a high light-emitting efficiency of the light-emitting device itself and a high brightness conversion rate of the light-emitting device for photoexcitation of the color conversion material can be ensured, and the contradiction between the high light-emitting efficiency of the light-emitting device and the high brightness conversion rate of the light-emitting device for photoexcitation of the color conversion material in the related art is solved.

[0078] Compared with the scheme in which the plurality of light-emitting layers 13 in the light-emitting device all adopt the same light-emitting material (for example, the first light-emitting material or the second light-emitting material), the light-emitting device provided in the embodiments of the present disclosure can improve the white light efficiency of the color conversion material.

[0079] The light-emitting device is electrically driven to emit light, and the color conversion material is photoexcited to emit light. In the combination of the light-emitting device and the color conversion material, the color conversion material emits light under the excitation of the light emitted by the light-emitting device. In this case, the white light efficiency of the color conversion material refers to the ratio between the brightness of the white light (for example, including red light, blue light and green light) emitted by the color conversion material and the current density for driving the light-emitting device to emit light.

[0080] In specific implementations, the plurality of light-emitting layers can include one first light-emitting layer 131 and one second light-emitting layer 132 arranged in a stack, as shown in FIG. 1A; or two first light-emitting layers 131 and one second light-emitting layer 132 arranged in a stack, as shown in FIG. 1B; or three first light-emitting layers 131 and one second light-emitting layer 132 arranged in a stack, as shown in FIG. 1C; or two first light-emitting layers 131 and two second light-emitting layers 132 arranged in a stack, as shown in FIG. 1D; or four first light-emitting layers 131 and one second light-emitting layer 132 arranged in a stack, as shown in FIG. 1E; or three first light-emitting layers 131 and two second light-emitting layers 132 arranged in a stack, as shown in FIG. 1F; and the like. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

[0081] The number of the first light-emitting layers 131 and the number of the second light-emitting layers 132 included in the plurality of light-emitting layers, and the stacking order between the plurality of light-emitting layers can be designed according to actual needs, and the present disclosure does not limit them.

[0082] ​​​​​​Optionally, the triplet energy level of the first light-emitting material is lower than the triplet energy level of the second light-emitting material. In this way, the triplet energy can be prevented from transferring between the different light-emitting layers 13, which can cause quenching of excitons, and the utilization rate of triplet excitons of the first light-emitting material and the second light-emitting material can be improved.

[0083] For example, the difference between the triplet energy level of the second light-emitting material and the triplet energy level of the first light-emitting material is greater than or equal to 0.1 eV and less than or equal to 0.3 eV. Further, the difference between the triplet energy level of the second light-emitting material and the triplet energy level of the first light-emitting material can be 0.2 eV.

[0084] Optionally, the first light-emitting material has greater molecular conjugation, and the second light-emitting material has smaller molecular conjugation. In a specific implementation, the molecular conjugation can be characterized by the molecular mass. The material with greater molecular conjugation usually has greater molecular mass, and the material with smaller molecular conjugation usually has smaller molecular mass.

[0085] Optionally, the first light-emitting material has greater molecular conjugation, and the second light-emitting material has smaller molecular conjugation. In a specific implementation, the molecular conjugation can be characterized by the molecular mass. The material with greater molecular conjugation usually has greater molecular mass, and the material with smaller molecular conjugation usually has smaller molecular mass.

[0086] Optionally, the first light-emitting material has greater molecular conjugation, and the second light-emitting material has smaller molecular conjugation. In a specific implementation, the molecular conjugation can be characterized by the molecular mass. The material with greater molecular conjugation usually has greater molecular mass, and the material with smaller molecular conjugation usually has smaller molecular mass.

[0087] Optionally, the first light-emitting material has greater molecular conjugation, and the second light-emitting material has smaller molecular conjugation. In a specific implementation, the molecular conjugation can be characterized by the molecular mass. The material with greater molecular conjugation usually has greater molecular mass, and the material with smaller molecular conjugation usually has smaller molecular mass.

[0088] Optionally, the first light-emitting material has greater molecular conjugation, and the second light-emitting material has smaller molecular conjugation. In a specific implementation, the molecular conjugation can be characterized by the molecular mass. The material with greater molecular conjugation usually has greater molecular mass, and the material with smaller molecular conjugation usually has smaller molecular mass.

[0089] Optionally, the first electrode 11 is a reflective electrode, and the second electrode 12 is a transmissive electrode or a semi-transmissive electrode. Accordingly, as shown in FIG. 1B, the second light-emitting layer 132 is located on the side of the first light-emitting layer 131 close to the first electrode 11. Figures 1 to 6

[0090] Since the first electrode 11 is a reflective electrode, and the second electrode 12 is a transmissive electrode or a semi-transmissive electrode, the multiple light-emitting layers 13 are located in a resonant cavity formed by a reflective film (i.e., the reflective electrode: the first electrode 11) and a transmissive film (i.e., the transmissive electrode or the semi-transmissive electrode: the second electrode 12), and a microcavity structure is formed between the reflective film and the transmissive film.

[0091] ​Since the luminous efficiency of the second light-emitting layer 132 is lower than that of the first light-emitting layer 131, by arranging the second light-emitting layer 132 at a position close to the first electrode 11 in the multiple light-emitting layers 13, the second light-emitting layer 132 with lower luminous efficiency is closer to the reflective film in the microcavity structure. This can improve the brightness conversion rate of the light-emitting device for light excitation of the color conversion material with little impact on the overall luminous efficiency of the light-emitting device, thereby further optimizing the white light efficiency.

[0092] Since the first light-emitting layer 131 has a high luminous efficiency, by setting the first light-emitting layer 131 at a position far away from the first electrode 11 in the multiple light-emitting layers 13, in the microcavity structure, the first light-emitting layer 131 with a higher luminous efficiency is farther away from the reflective film, thereby helping to improve the overall luminous efficiency of the light-emitting device.

[0093] In some exemplary embodiments, the plurality of light-emitting layers 13 may include at least two first light-emitting layers 131 and at least one second light-emitting layer 132 . In this case, the at least one second light-emitting layer 132 is located on a side of the at least two first light-emitting layers 131 close to the first electrode 11 .

[0094] For example, Figure 1 As shown, the multiple light-emitting layers 13 include a first light-emitting layer 131 and a second light-emitting layer 132, and the second light-emitting layer 132 is located on the side of the first light-emitting layer 131 close to the first electrode 11. That is, the first electrode 11, the second light-emitting layer 132, the first light-emitting layer 131 and the second electrode 12 are stacked in sequence.

[0095] like Figures 2 to 6 As shown, when the multiple light-emitting layers 13 include multiple first light-emitting layers 131 and one or more second light-emitting layers 132 , the one or more second light-emitting layers 132 are located on a side of the multiple first light-emitting layers 131 close to the first electrode 11 .

[0096] For example, Figure 2 As shown, the multiple light-emitting layers 13 include two first light-emitting layers 131 and one second light-emitting layer 132, and the second light-emitting layer 132 is located on the side of the two first light-emitting layers 131 close to the first electrode 11. That is, the first electrode 11, the second light-emitting layer 132, the two first light-emitting layers 131 and the second electrode 12 are stacked in sequence.

[0097] For example, Figure 3 As shown, the multiple light-emitting layers 13 include three first light-emitting layers 131 and one second light-emitting layer 132. The second light-emitting layer 132 is located on the side of the three first light-emitting layers 131 close to the first electrode 11. That is, the first electrode 11, the second light-emitting layer 132, the three first light-emitting layers 131 and the second electrode 12 are stacked in sequence.

[0098] Exemplarily, as shown in Figure 4 The plurality of light-emitting layers 13 include two first light-emitting layers 131 and two second light-emitting layers 132, and the two second light-emitting layers 132 are located on the side of the two first light-emitting layers 131 close to the first electrode 11. That is, the first electrode 11, the two second light-emitting layers 132, the two first light-emitting layers 131, and the second electrode 12 are sequentially stacked.

[0099] Exemplarily, as shown in Figure 5 The plurality of light-emitting layers 13 include two first light-emitting layers 131 and two second light-emitting layers 132, and the two second light-emitting layers 132 are located on the side of the two first light-emitting layers 131 close to the first electrode 11. That is, the first electrode 11, the two second light-emitting layers 132, the two first light-emitting layers 131, and the second electrode 12 are sequentially stacked.

[0100] Exemplarily, as shown in Figure 6 The plurality of light-emitting layers 13 include two first light-emitting layers 131 and two second light-emitting layers 132, and the two second light-emitting layers 132 are located on the side of the two first light-emitting layers 131 close to the first electrode 11. That is, the first electrode 11, the two second light-emitting layers 132, the two first light-emitting layers 131, and the second electrode 12 are sequentially stacked.

[0101] In specific implementations, the stacking structure of the second light-emitting layer 132 and the first light-emitting layer 131 is not limited to the above-mentioned several, for example: the second light-emitting layer 132 and the first light-emitting layer 131 can also be alternately arranged between the first electrode 11 and the second electrode 12, and the second light-emitting layer 132 is located on the side of the first light-emitting layer 131 close to the first electrode 11; the second light-emitting layer 132 can also be located on the side of the first light-emitting layer 131 close to the second electrode 11, etc., which are not limited by the present disclosure.

[0102] Optionally, as shown in Figure 1 or Figure 2 The light-emitting device further includes one or more of the functional film layers of the hole injection layer 14, the hole transport layer 15, the electron blocking layer 16, the hole blocking layer 17, the charge generation layer 18, the electron transport layer 19, and the electron injection layer 110, which are sequentially arranged between the first electrode 11 and the second electrode 12.

[0103] One or more of the above-mentioned functional film layers can be sequentially arranged between the first electrode 11 and the plurality of light-emitting layers 13, between two adjacent light-emitting layers 13, or between the plurality of light-emitting layers 13 and the second electrode 12, which can be arranged according to actual needs.

[0104] Exemplarily, the charge generation layer 18 can be arranged between any two adjacent light-emitting layers 13, so that the plurality of light-emitting layers 13 are connected in series through the charge generation layer 18, forming a series light-emitting device.

[0105] In the tandem light emitting device, the charge generation layer 18 can inject carriers (e.g. holes or electrons) into the adjacent light emitting layer 13. For a certain light emitting layer 13, part of the carriers are provided by the first electrode 11 and the second electrode 12, and the other part of the carriers are generated in the charge generation layer 18. Therefore, by providing the charge generation layer 18, the lifetime of the light emitting device can be improved, while the power consumption is reduced.

[0106] Optionally, the first electrode 11 is an anode, and the second electrode 12 is a cathode.

[0107] Optionally, as shown in Figure 1 or Figure 2 , the light emitting device further comprises a hole injection layer 14, a first hole transport layer 151 and a first electron blocking layer 161 which are stacked between the first electrode 11 and the plurality of light emitting layers 13, and the hole injection layer 14 is arranged close to the first electrode 11.

[0108] Optionally, as shown in Figure 1 or Figure 2 , the light emitting device further comprises a first hole blocking layer 171, a first charge generation layer 181, a second hole transport layer 152 and a second electron blocking layer 162 which are stacked between two adjacent light emitting layers, and the first hole blocking layer 171 is arranged close to the first electrode 11. The first charge generation layer 181 comprises an N-type charge generation layer and a P-type charge generation layer, and the N-type charge generation layer is arranged close to the first electrode 11.

[0109] Optionally, as shown in Figure 1 or Figure 2 , the light emitting device further comprises a second hole blocking layer 173, an electron transport layer 19 and an electron injection layer 110 which are stacked between the plurality of light emitting layers and the second electrode, and the electron injection layer 110 is arranged close to the second electrode.

[0110] Optionally, as shown in Figure 1 or Figure 2 , the light emitting device further comprises a light extraction layer arranged on the side of the second electrode 12 away from the first electrode 11.

[0111] Figure 1 The light emitting device shown in Figure 2 includes three light emitting layers 13, and is a three-layer tandem light emitting device. Figure 3 and Figure 4 includes four light emitting layers 13, and is a four-layer tandem light emitting device. Figure 5 and Figure 6The light-emitting device shown includes five light-emitting layers 13, which is a five-layer light-emitting device. Compared with a single-layer light-emitting device, a multi-layer light-emitting device can effectively improve the light-emitting efficiency of the device.

[0112] Referring to Figure 7 The spectral test results of the first light-emitting material and the second light-emitting material are schematically shown. As Figure 7 shown, the peak wavelength of the first light emitted by the first light-emitting material is 460 nm, and the full width at half maximum of the first light is 14.5 nm; the peak wavelength of the second light emitted by the second light-emitting material is 456 nm, and the full width at half maximum of the second light is 13.3 nm.

[0113] It should be noted that, Figure 7 The spectral test data of the first light-emitting layer 131 using the first light-emitting material and the second light-emitting layer 132 using the second light-emitting material are at the strongest interference in their respective microcavities.

[0114] In order to compare the performance of the light-emitting device, the inventors tested the performance of three light-emitting devices (including light-emitting device A, light-emitting device B and light-emitting device C), and the test results are shown in Figure 8 . Among them, the light-emitting device A, the light-emitting device B and the light-emitting device C are all three-layer light-emitting devices. The light-emitting device A and B are comparative examples, and the light-emitting device C is an experimental example. The three light-emitting layers 13 in the light-emitting device A are all first light-emitting layers 131, the three light-emitting layers 13 in the light-emitting device B are all second light-emitting layers 132, and the structure of the light-emitting device C is shown in Figure 2 .

[0115] From the peak wavelength column in Figure 8 , it can be seen that the peak wavelength of the light emitted by the light-emitting device A is 460 nm; the peak wavelength of the light emitted by the light-emitting device B is 456 nm; and the peak wavelength of the light emitted by the light-emitting device C is 459 nm.

[0116] From the light-emitting efficiency column of Figure 8 , it can be seen that under the same current density, the light-emitting efficiency of the light-emitting device A is taken as the base for normalization, the light-emitting efficiency of the light-emitting device A is 100%, the light-emitting efficiency of the light-emitting device B is 87%, and the light-emitting efficiency of the light-emitting device C is 97%.

[0117] The light-emitting device A, the light-emitting device B and the light-emitting device C are used to excite the color conversion material such as quantum dot film layer respectively, and the measured results are shown in the luminance conversion rate column of Figure 8 . Among them, the quantum dot film layer includes green quantum dots GQD and red quantum dots RQD.

[0118] In Figure 8In the brightness conversion rate column, the brightness conversion rate of the green quantum dots GQD photoexcited by the light emitted by the light-emitting device A is normalized as the base number, and the brightness conversion rates of the green quantum dots GQD and the red quantum dots RQD photoexcited by the light emitted by the light-emitting device A are both 100%.

[0119] The brightness conversion rate of the green quantum dots GQD excited by the light emitted by the light-emitting device B is 129%, and the brightness conversion rate of the red quantum dots RQD excited by the light emitted by the light-emitting device B is 126%.

[0120] The brightness conversion rate of the green quantum dots GQD excited by the light emitted by the light emitting device C is 120%, and the brightness conversion rate of the red quantum dots RQD excited by the light emitted by the light emitting device C is 115%.

[0121] Depend on Figure 8 It can be seen from the white light efficiency column in that, normalized based on the white light efficiency of light-emitting device A, the white light efficiency of light-emitting device A is 100%, the white light efficiency of light-emitting device B is 110%, and the white light efficiency of light-emitting device C is 114%.

[0122] Since the light-emitting layer in the light-emitting device C is composed of the first light-emitting layer 131 and the second light-emitting layer 132 , the light-emitting efficiency and the brightness conversion rate of the light-emitting device can be improved at the same time. Therefore, the white light efficiency of the light-emitting device C is optimal.

[0123] In addition, since the second light emitting layer 132 is disposed close to the first electrode 11 (eg Figure 2 As shown), the brightness conversion rate of the light-emitting device for light excitation of the color conversion material can be improved while having little impact on the overall luminous efficiency of the light-emitting device, thereby achieving optimal white light efficiency.

[0124] Optionally, the first light-emitting material and the second light-emitting material each include at least one of the following: an organic electroluminescent material and quantum dots.

[0125] Exemplarily, the first luminescent material and the second luminescent material are both organic electroluminescent materials. Accordingly, the light-emitting device is an organic light-emitting diode (OLED).

[0126] Exemplarily, the first luminescent material and the second luminescent material are both quantum dots. Accordingly, the light-emitting device is a quantum dot light-emitting diode (QLED).

[0127] It should be noted that in the actual process, due to the limitation of process conditions or other factors, the same in each of the above characteristics cannot be completely the same, and there may be some deviations, so as long as the same relationship between the above characteristics meets the above conditions, it belongs to the protection scope of the present disclosure. For example, the above same can be the same allowed within the error allowable range.

[0128] The present disclosure also provides a light-emitting substrate, as shown in Figure 9 or Figure 10 The light-emitting substrate comprises a first substrate 50, a plurality of switching elements T arranged on the first substrate 50, and a plurality of light-emitting devices 51 connected with the switching elements T, wherein the light-emitting device 51 is provided by any one of the above embodiments.

[0129] Those skilled in the art can understand that the light-emitting substrate has the advantages of the front light-emitting device.

[0130] Optionally, as shown in Figure 9 or Figure 10 The light-emitting substrate can further comprise a thin film encapsulation layer 52 arranged on the side of the plurality of light-emitting devices 51 away from the first substrate 50.

[0131] Optionally, the orthographic projection of the thin film encapsulation layer 52 on the first substrate 50 covers the first substrate 50.

[0132] Optionally, as shown in Figure 9 or Figure 10 The thin film encapsulation layer 52 can comprise a first inorganic layer ENL1, an organic layer ENL2 and a second inorganic layer ENL3 arranged in layers.

[0133] Optionally, as shown in Figure 9 or Figure 10 The light-emitting substrate can further comprise a color conversion layer 53 arranged on the light-emitting side of the light-emitting device 51, for receiving incident light and emitting light of a different color from the incident light, wherein the incident light is the light emitted by the light-emitting device 51.

[0134] When the light-emitting substrate comprises the above-mentioned thin film encapsulation layer 52 and color conversion layer 53, as shown in Figure 9 or Figure 10 The color conversion layer 53 is arranged on the side of the thin film encapsulation layer 52 away from the first substrate 50.

[0135] Optionally, as shown in Figure 11 The light-emitting substrate comprises an effective light-emitting area DA and a non-display area NDA arranged on at least one side of the effective light-emitting area DA, wherein the effective light-emitting area DA can comprise a plurality of pixels, and each pixel comprises a red sub-pixel R, a blue sub-pixel B and a green sub-pixel G. Figure 9The illustrated cross-sectional view is a schematic view of a cross-sectional structure of one pixel located in the effective light-emitting region DA.

[0136] As shown in Figure 9 or Figure 10 illustrated, the plurality of light-emitting devices 51 can include a first light-emitting device LD1 located in the red sub-pixel R, a second light-emitting device LD2 located in the green sub-pixel G, and a third light-emitting device LD3 located in the blue sub-pixel B. The sub-pixels and the light-emitting devices 51 can be arranged one-to-one.

[0137] Optionally, the incident light rays are blue light rays, i.e., the light rays emitted by the light-emitting devices 51 are blue light rays.

[0138] As shown in Figure 9 or Figure 10 illustrated, the color conversion layer 53 can include a first color conversion pattern CCP1 located in the red sub-pixel R, for emitting red light rays under excitation of the incident light rays.

[0139] Optionally, the first color conversion pattern CCP1 covers the light-emitting region (such as the opening region illustrated in Figure 9 or Figure 10 ) of the light-emitting device 51 at the corresponding position in the first substrate 50 in the orthographic projection on the first substrate 50.

[0140] As shown in Figure 9 or Figure 10 illustrated, the color conversion layer 53 can further include a second color conversion pattern CCP2 located in the green sub-pixel G, for emitting green light rays under excitation of the incident light rays.

[0141] Optionally, the second color conversion pattern CCP2 covers the light-emitting region (such as the opening region illustrated in Figure 9 or Figure 10 ) of the light-emitting device 51 at the corresponding position in the first substrate 50 in the orthographic projection on the first substrate 50.

[0142] As shown in Figure 9 or Figure 10 illustrated, the color conversion layer 53 can further include a transmission pattern TP located in the blue sub-pixel B, for transmitting the incident light rays.

[0143] Optionally, the transmission pattern TP covers the light-emitting region (such as the opening region illustrated in Figure 9 or Figure 10 ) of the light-emitting device at the corresponding position in the first substrate 50 in the orthographic projection on the first substrate 50.

[0144] Exemplarily, as shown in Figure 9 or Figure 10As shown, the color conversion layer 53 includes partition walls PW, and a plurality of color conversion patterns within a plurality of openings defined by the partition walls PW. The plurality of color conversion patterns includes at least a first color conversion pattern CCP1, a second color conversion pattern CCP2, and a transmission pattern TP.

[0145] The first color conversion pattern CCP1 can emit light by converting or shifting a peak wavelength of incident light to another specific peak wavelength. The first color conversion pattern CCP1 can convert the emission light L provided from the first light emitting device LD1 to red light having a peak wavelength in a range of about 610 nm to about 650 nm. Referring to Figure 12 , the first color conversion pattern CCP1 can include a first base resin R1 and a first color conversion material QD1 dispersed in the first base resin R1, and can include a first scattering particle SP1 dispersed in the first base resin R1.

[0146] The second color conversion pattern CCP2 can emit light by converting or shifting a peak wavelength of incident light to another specific peak wavelength. The second color conversion pattern CCP2 can convert the emission light L provided from the second light emitting element LD2 to green light having a peak wavelength in a range of about 510 nm to about 550 nm. Referring to Figure 13 , the second color conversion pattern CCP2 can include a second base resin R2 and a second color conversion material QD2 dispersed in the second base resin R2, and can include a second scattering particle SP2 dispersed in the second base resin R2.

[0147] The transmission pattern TP can transmit incident light, for example, having a transmittance of over 90% for the peak wavelength of the incident light. The transmission pattern TP can transmit the emission light L provided from the third light emitting element LD3. Referring to Figure 14 , the transmission pattern TP can include a third base resin R3 and a third scattering particle SP3 dispersed in the third base resin R3. The provision of the third scattering particle SP3 can expand the viewing angle range of the incident light rays, improving the viewing angle uniformity between the red sub-pixel R, the blue sub-pixel B, and the green sub-pixel G.

[0148] The first color conversion material QD1 and the second color conversion material QD2 can include a semiconductor nanocrystal material, which can emit light of a specific color in the case where an electron jumps from a conduction band to a valence band. The quantum dots can have any shape that is commonly used in the art, and specifically can be spherical, conical, multi-armed, or cubic nanoparticles, or can be nanotubes, nanowires, nanofibers, or nanoparticles, etc.

[0149] In some embodiments, the quantum dots can have a core-shell structure including a core material and a shell material; the core-shell structure includes a core of a nanocrystal and a shell surrounding the core. The shell of the quantum dot can serve as a protective layer for preventing chemical modification of the core and maintaining semiconductor properties and / or as a charging layer for imparting electrophoretic properties to the quantum dot. The shell can have a single-layer structure or a multi-layer structure. The interface between the core and the shell can have a concentration gradient of the elements in the shell decreasing toward the center of the core. The core of the quantum dot can be selected from the group consisting of: Group II-VI compounds, Group III-V compounds, Group IV-VI compounds, Group IV elements, Group IV compounds, and combinations thereof. The shell of the quantum dot can include oxides of metallic or non-metallic materials, semiconductor compounds, or combinations thereof. A transition material can be added between the core material and the shell material to achieve a gradual transition of the lattice, effectively reducing internal stress caused by lattice defects of the quantum dot, thereby further improving the light emitting efficiency and stability of the quantum dot.

[0150] In some embodiments, the Group II-VI compound can be selected from the group consisting of: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and binary compounds selected from the group formed by mixtures thereof; AgInS, CuInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and ternary compounds selected from the group formed by mixtures thereof; and HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and quaternary compounds selected from the group formed by mixtures thereof.

[0151] In some embodiments, the III-V compound can be selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and binary compounds selected from the group formed by mixtures thereof; GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNAs, InNP, InNAs, InNSb, InPAs, InPSb, and ternary compounds selected from the group formed by mixtures thereof; and GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and quaternary compounds selected from the group formed by mixtures thereof.

[0152] In some embodiments, the III-V compound can be selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and binary compounds selected from the group formed by mixtures thereof; GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNAs, InNP, InNAs, InNSb, InPAs, InPSb, and ternary compounds selected from the group formed by mixtures thereof; and GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and quaternary compounds selected from the group formed by mixtures thereof.

[0153] In some embodiments, the transition material can be a ternary alloy material. By controlling the optical performance of the quantum dots through the ternary alloy material, quantum dots with consistent volume but different light emitting frequencies can be formed, thereby improving the color gamut coverage of the display device.

[0154] In some embodiments, the core material of the quantum dot includes CdSe and / or InP, and the shell material includes ZnS. For example, when the core material includes InP, the surface defects of the InP quantum dot form surface trap states. By coating the surface of the InP quantum dot with ZnS, a core-shell structure with InP as the core material and ZnS as the shell material can reduce the surface defects of the quantum dot, and optimize the light-emitting efficiency and stability of the quantum dot. The above is only an example of the core material including InP. When the core material includes CdSe, or the core material includes CdSe and InP, the above rules are also applicable.

[0155] In some embodiments, the quantum dot QD does not include cadmium (Cd), for example, the core material of the QD is InP, and the shell material is a stack of ZnSe / ZnS; or for example, the core material of the QD is ZnTeSe, and the shell material is ZnSe / ZnS.

[0156] The quantum dot can have a size of less than 45 nanometers (nm), for example, 40 nm, 30 nm, 20 nm, or less. In some embodiments, the size of the quantum dot is 4 nm to 20 nm, for example, 4 nm, 5 nm, 7 nm, 10 nm, 13 nm, 17 nm, or 20 nm. The quantum dot can adjust the color of the emitted light according to its size, and thus the quantum dot can emit light of various colors, such as blue light, red light, green light, etc. Among them, the size of the red quantum dot and the size of the green quantum dot can be different.

[0157] Among them, the first color conversion material QD1 and the second color conversion material QD2 are not limited to the quantum dot materials described above, and can also be selected from one or more of quantum dots, rare earth materials, fluorescent materials, and organic dyes.

[0158] When the light-emitting device is an OLED and the color conversion layer 53 uses quantum dot materials, the combination of pixel-level control of the OLED and the color enhancement characteristics of the quantum dots can be achieved, better display characteristics can be obtained, power consumption can be reduced, and the service life of the light-emitting substrate can be prolonged. In addition, during the preparation of a plurality of light-emitting devices 51, the light-emitting layers located in different sub-pixels can be formed in a whole surface, for example, an open mask can be used to synchronously form the light-emitting layers located in different sub-pixels, thereby simplifying the preparation process.

[0159] Using a blue OLED as a backlight, the quantum dot materials in the red sub-pixel R and the green sub-pixel G are excited to emit red light and green light, and the transmission pattern TP located in the blue sub-pixel B scatters and transmits the incident light to emit blue light with an expanded viewing angle, which is mixed with the red light and the green light to form white light, thereby realizing picture display.

[0160] Alternatively, as Figure 9 or Figure 10 As shown in FIG. 1, the light-emitting device further includes a color filter layer 54 disposed on the light-exit side of the color conversion layer 53.

[0161] Optionally, as shown in FIG. 2, the color filter layer 54 includes a first color filter pattern CF1 located on the red sub-pixel R and configured to transmit red light incident on the first color filter pattern CF1. Figure 9 or Figure 10 As shown in FIG. 3, the color filter layer 54 includes a second color filter pattern CF2 located on the green sub-pixel G and configured to transmit green light incident on the second color filter pattern CF2.

[0162] Optionally, as shown in FIG. 4, the color filter layer 54 includes a third color filter pattern CF3 located on the blue sub-pixel B and configured to transmit blue light incident on the third color filter pattern CF3. Figure 9 or Figure 10 As shown in FIG. 5, the color filter layer 54 includes a third color filter pattern CF3 located on the blue sub-pixel B and configured to transmit blue light incident on the third color filter pattern CF3.

[0163] In a specific implementation, referring to FIG. 6, the first substrate 50 can be sequentially formed with the plurality of switching elements T, the planarization layer PLN, the first electrode 11, the pixel definition layer PDL, the plurality of light-emitting layers 13, the second electrode 12, the thin-film encapsulation layer 52, the color conversion layer 53, and the color filter layer 54 to obtain the light-emitting substrate shown in FIG. 6. Figure 9 or Figure 10 As shown in FIG. 7, the light-emitting device further includes a second substrate 55 disposed on the side of the color filter layer 54 away from the color conversion layer 53, and a filling layer FL disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 and configured to bond the thin-film encapsulation layer 52 and the color conversion layer 53.

[0164] In a specific implementation, referring to FIG. 8, the first substrate 50 can be sequentially formed with the plurality of switching elements T, the planarization layer PLN, the first electrode 11, the pixel definition layer PDL, the plurality of light-emitting layers 13, the second electrode 12, and the thin-film encapsulation layer 52 to obtain the substrate LS in the light-emitting substrate shown in FIG. 8; the color filter layer 54 and the color conversion layer 53 can be sequentially formed on the second substrate 55 to obtain the substrate CS in the light-emitting substrate shown in FIG. 8; and then the filling layer FL can be used to bond the substrate LS and the substrate CS, with the filling layer FL being disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 to obtain the light-emitting substrate shown in FIG. 8. Figure 10 Figure 10 As shown in FIG. 9, the light-emitting device further includes a second substrate 55 disposed on the side of the color filter layer 54 away from the color conversion layer 53, and a filling layer FL disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 and configured to bond the thin-film encapsulation layer 52 and the color conversion layer 53.

[0165] In a specific implementation, referring to FIG. 10, the first substrate 50 can be sequentially formed with the plurality of switching elements T, the planarization layer PLN, the first electrode 11, the pixel definition layer PDL, the plurality of light-emitting layers 13, the second electrode 12, and the thin-film encapsulation layer 52 to obtain the substrate LS in the light-emitting substrate shown in FIG. 10; the color filter layer 54 and the color conversion layer 53 can be sequentially formed on the second substrate 55 to obtain the substrate CS in the light-emitting substrate shown in FIG. 10; and then the filling layer FL can be used to bond the substrate LS and the substrate CS, with the filling layer FL being disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 to obtain the light-emitting substrate shown in FIG. 10. Figure 9 or As shown in FIG. 11, the light-emitting device further includes a second substrate 55 disposed on the side of the color filter layer 54 away from the color conversion layer 53, and a filling layer FL disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 and configured to bond the thin-film encapsulation layer 52 and the color conversion layer 53.

[0166] In a specific implementation, referring to FIG. 12, the first substrate 50 can be sequentially formed with the plurality of switching elements T, the planarization layer PLN, the first electrode 11, the pixel definition layer PDL, the plurality of light-emitting layers 13, the second electrode 12, and the thin-film encapsulation layer 52 to obtain the substrate LS in the light-emitting substrate shown in FIG. 12; the color filter layer 54 and the color conversion layer 53 can be sequentially formed on the second substrate 55 to obtain the substrate CS in the light-emitting substrate shown in FIG. 12; and then the filling layer FL can be used to bond the substrate LS and the substrate CS, with the filling layer FL being disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 to obtain the light-emitting substrate shown in FIG. 12.

[0167] Figure 9 As shown in FIG. 13, the light-emitting device further includes a second substrate 55 disposed on the side of the color filter layer 54 away from the color conversion layer 53, and a filling layer FL disposed between the thin-film encapsulation layer 52 and the color conversion layer 53 and configured to bond the thin-film encapsulation layer 52 and the color conversion layer 53. Figure 9 Figure 9 ​​The light-emitting substrate shown.

[0168] The present disclosure also provides a light-emitting device, which includes the light-emitting substrate as described in any embodiment; a driving integrated circuit configured to provide a driving signal to the light-emitting substrate; and a power supply circuit configured to provide power to the light-emitting substrate.

[0169] Those skilled in the art will appreciate that the light emitting device has the advantages of the previous light emitting device.

[0170] In some embodiments, the light emitting device may be a lighting device, in which case the light emitting device serves as a light source to achieve a lighting function. For example, the light emitting device may be a backlight module in a liquid crystal light emitting device, a lamp for internal or external lighting, or various signal lights.

[0171] In other embodiments, the light-emitting device may be a display device, in which case the light-emitting device has the function of displaying an image (i.e., a picture). The light-emitting device may include a display or a product including a display. The display may be a flat panel display (FPD), a microdisplay, and the like. If divided according to whether the user can see the back of the display, the display may be a transparent display or an opaque display. If divided according to whether the display can be bent or curled, the display may be a flexible display or an ordinary display (which may be called a rigid display). Exemplarily, products including displays may include: computers, televisions, billboards, laser printers with display functions, telephones, mobile phones, electronic paper, personal digital assistants (PDAs), laptop computers, digital cameras, tablet computers, notebook computers, navigation systems, camcorders, viewfinders, vehicles, large-area walls, theater screens, or stadium signs.

[0172] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0173] Finally, it should be noted that the terms "first" and "second", and the like, herein do not denote any order, quantity, combination or importance, but are used to identify one element from another, and do not imply referring to a certain number of terms, but are only used to identify an element from another, unless otherwise specified. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0174] The above detailed description of a light-emitting device, a light-emitting substrate and a light-emitting apparatus provided by the present disclosure has been described in detail, and the principles and embodiments of the present disclosure have been described herein by applying specific examples. The above description of the embodiments is only used to help understand the method of the present disclosure and its core idea; meanwhile, for those skilled in the art, according to the idea of the present disclosure, the specific embodiments and application scope will be changed; therefore, the content of the specification should not be understood as a limitation of the present disclosure.

[0175] Other embodiments of the present disclosure will be apparent to those skilled in the art upon consideration of the specification and practice of the disclosed application. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure following, in general, the principles of the present disclosure and including such departures from the present disclosure that come within known or customary practice within the art to which the present disclosure pertains. The specification and examples are to be considered exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0176] It should be understood that the present disclosure is not limited to the precise construction that has been described and shown in the accompanying drawings, and that various modifications and changes can be effected therein by those skilled in the art without departing from the scope of the application. The scope of the present disclosure is limited only by the claims that follow.

[0177] As used herein, the term "one embodiment", "an embodiment", or "one or more embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0178] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the disclosure can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0179] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present disclosure may be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.

Claims

1. A light-emitting device, comprising: a first electrode; a second electrode, disposed opposite to the first electrode; and a plurality of light-emitting layers, stacked between the first electrode and the second electrode, the plurality of light-emitting layers comprising at least one first light-emitting layer and at least one second light-emitting layer, the second light-emitting layer being located on a side of the first light-emitting layer closer to the first electrode; wherein the first light-emitting layer comprises a first light-emitting material configured to emit a first light under driving of a current or a voltage; the second light-emitting layer comprises a second light-emitting material configured to emit a second light under driving of the current or the voltage; a light-emitting efficiency of the first light-emitting material is greater than a light-emitting efficiency of the second light-emitting material; and a luminance conversion rate of the first light to photo-excite a color conversion material is less than a luminance conversion rate of the second light to photo-excite the color conversion material. a triplet energy level of the first light-emitting material is lower than a triplet energy level of the second light-emitting material.

2. The light-emitting device according to claim 1, wherein a difference between the triplet energy level of the second light-emitting material and the triplet energy level of the first light-emitting material is greater than or equal to 0.1 eV and less than or equal to 0.3 eV.

3. The light emitting device of claim 2, wherein, a molecular mass of the first light-emitting material is greater than a molecular mass of the second light-emitting material.

4. The light-emitting device according to claim 1, wherein a peak wavelength of the first light is greater than a peak wavelength of the second light.

5. The light emitting device of claim 1, wherein, the peak wavelength of the first light is greater than or equal to 460 nanometers and less than or equal to 470 nanometers; and the peak wavelength of the second light is greater than or equal to 450 nanometers and less than or equal to 460 nanometers.

6. The light-emitting device according to claim 5, wherein a full width at half maximum of the first light and the second light is less than or equal to 20 nanometers.

7. The light-emitting device according to claim 1, wherein the first electrode is a reflective electrode, and the second electrode is a transmissive electrode or a semi-transmissive electrode.

8. The light-emitting device according to any one of claims 1 to 7, wherein the plurality of light-emitting layers comprises at least two first light-emitting layers, and the at least one second light-emitting layer is located on a side of the at least two first light-emitting layers closer to the first electrode.

9. The light-emitting device according to claim 8, wherein The light-emitting device further comprises at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, a charge generation layer, an electron transport layer, and an electron injection layer, stacked between the first electrode and the second electrode.

10. The light-emitting device according to any one of claims 1 to 7, wherein the first electrode is an anode, and the second electrode is a cathode, and the light-emitting device further comprises:

11. The light-emitting device according to any one of claims 1 to 7, wherein a hole injection layer, a first hole transport layer, and a first electron blocking layer, stacked between the first electrode and the plurality of light-emitting layers, the hole injection layer being disposed closer to the first electrode; a first hole blocking layer, a first charge generation layer, a second hole transport layer, and a second electron blocking layer, stacked between two adjacent light-emitting layers, the first hole blocking layer being disposed closer to the first electrode; a second hole blocking layer, an electron transport layer, and an electron injection layer, stacked between the plurality of light-emitting layers and the second electrode, the electron injection layer being disposed closer to the second electrode; and a light extraction layer disposed on a side of the second electrode away from the first electrode. the first light-emitting material and the second light-emitting material each comprise at least one of an organic electroluminescent material and a quantum dot.

12. The light-emitting device according to any one of claims 1 to 7, wherein 13. A light-emitting substrate, comprising: a first substrate; ​ a plurality of switching elements disposed on the first substrate; and a plurality of light emitting devices as claimed in any one of claims 1 to 12 connected to the switching elements.

14. The light emitting substrate of claim 13, further comprising: a thin film encapsulation layer disposed on a side of the light emitting devices away from the first substrate, a projection of the thin film encapsulation layer on the first substrate covering the first substrate.

15. The light emitting substrate of claim 13, further comprising: a color conversion layer disposed on a light emitting side of the light emitting devices for receiving incident light and emitting light of a different color than the incident light, the incident light being light emitted by the light emitting devices.

16. The light-emitting substrate of claim 15, wherein, the incident light being blue light, the light emitting substrate comprising a plurality of pixels, each of the pixels comprising a red sub-pixel, a blue sub-pixel, and a green sub-pixel; the color conversion layer comprising at least one of: a first color conversion pattern located at the red sub-pixel for emitting red light under excitation of the incident light; a second color conversion pattern located at the green sub-pixel for emitting green light under excitation of the incident light; and a transmission pattern located at the blue sub-pixel for transmitting the incident light. the color conversion layer comprising a color conversion material, the color conversion material comprising at least one of: quantum dots, rare earth materials, fluorescent materials, and organic dyes.

17. The light-emitting substrate of claim 15, wherein, 18. The light emitting substrate of claim 16, further comprising: a color filter layer disposed on a light emitting side of the color conversion layer, comprising: a first color filter pattern located at the red sub-pixel for transmitting red light incident to the first color filter pattern; a second color filter pattern located at the green sub-pixel for transmitting green light incident to the second color filter pattern; and a third color filter pattern located at the blue sub-pixel for transmitting blue light incident to the third color filter pattern.

19. The light emitting substrate of claim 18, further comprising: a second substrate disposed on a side of the color filter layer away from the color conversion layer; and a filling layer disposed between the thin film encapsulation layer and the color conversion layer for bonding the thin film encapsulation layer and the color conversion layer; wherein the thin film encapsulation layer is located between the light emitting devices and the color conversion layer.

20. A light emitting apparatus, comprising: a light emitting substrate as claimed in any one of claims 13 to 19; a driving integrated circuit configured to provide driving signals to the light emitting substrate; and a power supply circuit configured to provide power to the light emitting substrate. ​ ​ ​

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