Patent Application
20210265585
The present disclosure generally relates to the display technology and, more particularly, relates to an OLED display panel, an electronic device and a manufacturing method thereof.
Generally, the structure of an organic electroluminescent device often include an anode, an auxiliary function layer (e.g., a hole transport layer, an electron transport layer, and an electron injection layer, etc.), a light-emitting layer, and a cathode. When a voltage is applied between the anode and the cathode, the holes and electrons are transported to the light-emitting layer to be recombined to form excitons in the light-emitting layer. Driven by the electric field, the excitons are migrated to transfer the energy to the light-emitting material, thereby stimulating electrons in the light-emitting material to transition from a base state to an excited state. Through radiation inactivation, the energy at the excited state produces photons to emit light.
In an existing organic electroluminescent device, the holes and electrons often pass through the light-emitting layer to reach the cathode and the anode, respectively. The energy carried by such holes and electrons may not be utilized to stimulate the light-emitting material to emit light, reducing the efficiency and life span of the device. At the same time, the recombined holes and electrons often form excitons which diffuse laterally. Some excitons may diffuse to other regions that have not been doped with light-emitting material, such as a hole transport layer or an electron transport layer, then may get attenuated. However, such attenuated excitons do not produce any photons. Thus, the light-emitting efficiency of such organic electroluminescent device may be reduced.
In addition, excessive accumulation of electrons and holes in the hole transport layer and the electron transport layer may cause the materials in the hole transport layer and the electron transport layer to have an unstable charged state. Irreversible chemical reaction is likely to occur to such charged material, and the material properties may change or deteriorate. As a result, a reduction in efficiency and life span of the device may be obviously observed.
The disclosed OLED display panel, electronic device and manufacturing method are directed to solve one or more problems set forth above and other problems.
One aspect of the present disclosure provides an OLED display panel, comprising a first electrode, a light-emitting layer, a first function layer, and a second electrode. The first function layer includes at least a first-type blocking layer disposed adjacent to the light-emitting layer. A first guest material is doped into a host material of the first-type blocking layer, and a ratio of a second-type carrier mobility of the host material over a second-type carrier mobility of the first guest material is greater than or equal to about 10. The first-type is a hole-type and the second-type is an electron-type, or the first-type is an electron-type and the second-type is a hole-type.
Another aspect of the present disclosure provides an electronic device, including a disclosed OLED display panel.
Another aspect of the present disclosure provides a manufacturing method for the OLED display panel, comprising sequentially forming a first electrode, a light-emitting layer, a first function layer, and a second electrode, or sequentially forming a second electrode, a first function layer, a light-emitting layer, and a first electrode. The first function layer includes at least a first-type blocking layer disposed adjacent to the light-emitting layer, a first guest material is doped into a host material of the first function layer, and a ratio of a second-type carrier mobility of the host material over a second-type carrier mobility of the first guest material is greater than or equal to about 10. The first-type is a hole-type and the second-type is an electron-type, or the first-type is an electron-type and the second-type is a hole-type.
Other aspects of the present disclosure can be understood by those skilled in the art in light of the description, the claims, and the drawings of the present disclosure.
The following drawings are merely examples for illustrative purposes according to various disclosed embodiments and are not intended to limit the scope of the present disclosure.
Reference will now be made in detail to exemplary embodiments of the disclosure, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. It should be understood that the exemplary embodiments described herein are only intended to illustrate and explain the present invention and not to limit the present invention. In addition, it should also be noted that, for ease of description, only part, but not all, of the structures associated with the present invention are shown in the accompanying drawings.
The present disclosure provides an OLED display panel comprising at least a first electrode, a light-emitting layer, a first function layer, and a second electrode, which are disposed in layers. The first function layer may include at least a first-type blocking layer, which may be disposed adjacent to the light-emitting layer. A first guest material may be doped in the first-type blocking layer. In the first-type blocking layer, the ratio of the mobility of the second-type carrier inside the host material over the mobility of the second-type carrier inside the first guest material may be greater than or equal to about 10.
In one embodiment, the above-mentioned first-type may be a hole-type, and the above-mentioned second-type may be an electron-type. Accordingly, the first electrode may be an anode of an OLED device, and the second electrode may be a cathode of the OLED device. In another embodiment, the above-mentioned first-type may be an electron-type, and the above-mentioned second-type may be a hole-type. Accordingly, the first electrode may be a cathode of an OLED device, and the second electrode may be an anode of the OLED device. The anode may be a transparent conductive film made of ITO, AZO, or IZO. The cathode may be made of Al, Pt, Au, Ag, MgAg alloy, YbAg alloy, or Ag rare earth metal alloy. In addition to the first-type blocking layer, the first function layer may further include at least one of a second-type injection layer, and a second-type transport layer.
In one embodiment, to prevent the excitons formed by recombined electrons and holes from diffusing laterally to other layers on both sides of the light-emitting layer, the locations where excitons are recombined to emit light may be adjusted in an electron-rich OLED device or a hole-rich OLED device.
For example, in the electron-rich OLED device, the OLED display panel according to the present disclosure may comprise at least a first electrode, a light-emitting layer, a first function layer, and a second electrode, which are disposed in layers. The first function layer may include at least a hole blocking layer, which may be disposed adjacent to the light-emitting layer. A first guest material may be doped in the hole blocking layer. In the hole blocking layer, the ratio of the electron mobility of the host material over the electron mobility of the first guest material may be configured to be greater than or equal to about 10.
Because the hole blocking layer is disposed between the light-emitting layer and the second electrode, the hole blocking layer may be able to prevent an excessive number of holes from passing through the light-emitting layer to reach the side of the light-emitting layer far away from the first electrode. Thus, the excitons may be prevented from diffusing to regions other than the light-emitting layer and, accordingly, the utilization of the excitons and the light-emitting efficiency of the device may be improved.
Further, the guest material (i.e., the first guest material) may be doped into the hole blocking layer. In the hole blocking layer, the ratio of the electron mobility of the host material over the electron mobility of the first guest material may be configured to be greater than or equal to about 10. That is, the guest material having a smaller electron mobility than the host material may be doped in the hole blocking layer. For the electron-rich OLED device, the guest material having a substantially small electron mobility may reduce the electron movement, adjust the balance of the electrons and holes in the light-emitting layer, confine the electron and hole recombination in the light-emitting layer, and increase the light-emitting efficiency and life span of the device.
Further, the guest and host materials in the hole blocking layer may have a higher triplet state energy level than the light-emitting layer, preventing the excitons formed by the electron and hole recombination from diffusing to organic layers other than the light-emitting layer. Thus, the efficiency of the organic electroluminescent device may be improved.
For example, in the hole-rich OLED device, the OLED display panel according to the present disclosure may comprise at least a first electrode, a light-emitting layer, a first function layer, and a second electrode, which are disposed in layers. The first function layer may include at least an electron blocking layer, which may be disposed adjacent to the light-emitting layer. A first guest material may be doped into the electron blocking layer. In the electron blocking layer, the ratio of the hole mobility of the host material over the hole mobility of the first guest material may be configured to be greater than or equal to about 10.
Because the electron blocking layer may be disposed between the light-emitting layer and the second electrode, the electron blocking layer may be able to prevent an excessive number of electrons from passing through the light-emitting layer to reach the side of the light-emitting layer far away from the first electrode. Thus, the excitons may be prevented from diffusing to regions other than the light-emitting layer and, accordingly, the excitons utilization and the light-emitting efficiency of the device may be improved.
Further, the guest material (i.e., first guest material) may be doped in the electron blocking layer, and in the electron blocking layer, the ratio of the hole mobility of the host material over the hole mobility of the guest material may be configured to be greater than or equal to about 10. That is, the guest material having a smaller hole mobility than the host material may be doped into the electron blocking layer. For the hole-rich OLED device, the guest material having a substantially small hole mobility may reduce the hole movement, adjust the balance of the electrons and holes in the light-emitting layer, confine the electron and hole recombination in the light-emitting layer, and increase the light-emitting efficiency and life span of the device.
Further, the guest and host materials in the electron blocking layer may have a higher triplet state energy level than the light-emitting layer, preventing the excitons formed by the electron and hole recombination from diffusing to organic layers other than the light-emitting layer. Thus, the efficiency of the organic electroluminescent device may be improved.
In particular, the first function layer 30 may include at least a hole blocking layer 31. The hole blocking layer 31 may be disposed adjacent to the light-emitting layer 20. In one embodiment, as shown in
In general, the electrons and holes in the OLED devices are not balanced. For the hole-rich OLED device, the electrons and holes may be recombined in a region or the surface of the light-emitting layer 20 which is adjacent to the second electrode 40, such that the electrons and holes may be recombined in a narrow region. When a current density is substantially high, the exciton density in the narrow region may be substantially high. Excitons may interact with each other to cause, for example, triplet-triplet annihilation, and triplet-singlet annihilation, etc., such that the exciton utilization may be reduced, and the efficiency of the OLED display panel may be reduced accordingly. At the same time, a large number of excitons accumulated in the narrow region may cause the light-emitting material to deteriorate and, thus, the life span of the OLED display device may be reduced.
Further, in one embodiment, a first guest material A may be doped in a host material B of the hole blocking layer 31. In the hole blocking layer 31, the ratio of the electron mobility (μe_B) corresponding to the host material B over the electron mobility (μe_A) corresponding to the first guest material A may be configured to be greater than or equal to about 10. That is, the first guest material A having a smaller electron mobility (μe_A) than the host material B may be doped in the hole blocking layer 31.
In the hole blocking layer 31 of the electron-rich device, the first guest dopant material A, which has a smaller electron mobility (μe_A) than the guest material B, may reduce the electron movement, adjust the balance of the electrons and holes in the light-emitting layer 20, confine the electron and hole recombination in the light-emitting layer 20, and increase the light-emitting efficiency and life span of the device.
In one embodiment, the first electrode 10 may be an anode, and the second electrode 40 may be a cathode. Optionally, the first function layer 30 may also include at least one of an electron injection layer 33, and an electron transport layer 32. For example, referring to
The hole blocking layer 31 may include electron transport type materials. The hole blocking layer 31 may include at least one of metal complexes, oxadiazole-based materials, imidazole-based materials, triazole-based materials, pyridine-based materials, o-phenanthroline-based materials, organoboron-based materials, and organosilicon-based materials.
The host material B of the hole blocking layer 31 may include, for example, at least one of 3,3′-[5′-[3-(3-pyridinyl)phenyl][1,1′:3′,1″-terpheny1]-3,3″-diy1]bispyridine (TmPyPB), 4,4-bis(9-carbazolyl)-1,1′-biphenyl (BCP), 4,6-bis(3,5-di(pyridine-4-yl)phenyl)-2-MethylpyriMidine (B4PyMPM), star oxadiazole, and 1,3,5-tris(N-phenyl-2-benzimidazole) benzene (TPBi). The first guest material A of the hole blocking layer 31 may include, for example, at least one of 8-hydroxyquinoline aluminum (Alq3), 8-hydroxyquinoline lithium (Liq), 2-(4-biphenyl)-5-phenyl oxadiazole (PBD), 2,5-bis-(4-naphthyl)-1,3,4-oxadiazole (BND), tris-(2,3,5,6-trimethyl)phenylboron, and 2,5-diaryl silicon.
The skeletal structural formula of 4,6-bis(3,5-di(pyridine-4-yl)phenyl)-2-MethylpyriMidine (B4PyMPM) is
The skeletal structural formula of 2,5-bis-(4-naphthyl)-1,3,4-oxadiazole (BND) is
The skeletal structural formula of 2,5-diaryl silicon is
The skeletal structural formula of star oxadiazole is
The skeletal structural formula of tris-(2,3,5,6-trimethyl)phenylboron is
The skeletal structural formula of 1,3,5-tris(N-phenyl-2-benzimidazole) benzene (TPBi) is
In one embodiment, the highest occupied orbital level HOMOB of the host material B of the hole blocking layer 31 may be at least approximately 0.3 eV higher than the highest occupied orbital level HOMOC of the host material C of the light-emitting layer 20, and the highest occupied orbital level HOMOA of the first guest material A of the hole blocking layer 31 may be at least approximately 0.3 eV higher than the highest occupied orbital level HOMOC of the host material C of the light-emitting layer 20, such that the hole blocking layer 31 may be effective in blocking hole movement.
In the electroluminescent process, the singlet and triplet excitons may be generated in a ratio of approximately 1:3 and, thus, it is critical to effectively utilize the triplet excitons to improve the device efficiency. Thus, the triplet state energy level TB of the host material B of the hole blocking layer 31 may be configured to be greater than the triplet state energy level TC of the host material C of the light-emitting layer 20, and the triplet state energy level TA of the first guest material A of the hole blocking layer 31 may be configured to be greater than the triplet state energy level TC of the host material C of the light-emitting layer 20, which may improve the utilization rate of the triplet state excitons from the device structure perspective.
After the triplet state excitons are generated in the light-emitting layer 20, through utilizing the higher triplet state energy level property of the hole blocking layer 31, the triplet state excitons in the light-emitting layer 20 may be prevented from being transported to other layers (e.g., the electron transport layer 32) outside the light-emitting layer 20. Thus, the exciton utilization rate of the device may be improved, and the light-emitting efficiency of the device may be increased.
The content of the host material B in the hole blocking layer 31 may be determined according to various application scenarios. In one embodiment, the content (i.e., weight percentage) of the host material B in the hole blocking layer 31 may be configured to be greater than or equal to about 90%. Provided that the content of the host material B effectively confine the holes in the light-emitting layer 20, through doping the first guest material A into the host material B of the hole blocking layer 31, the electron injection rate into the light-emitting layer 20 may be reduced, and the electrons and holes in the light-emitting layer 20 may be balanced, such that the electrons and holes may be recombined in the center of the light-emitting layer 20. The exciton binding region may be widened, and the efficiency and life span of the device may be increased.
In one embodiment, the electron mobility of the host material B and the first guest material A in the hole blocking layer 31 may be configured to be 10−4 cm−2/V·S≤μe_B≤10−3 cm−2/V·S, and μe_A≤10−4 cm−2/V·S, respectively. The host material B and the first guest material A may be selected to satisfy the above relationship, such that the efficiency and life span of the device may be increased.
For example, μe_B may be approximately 10−3 cm−2/V·S, and μe_A may be approximately 10−4 cm−2/V·S. The hole blocking layer 31 may have a thickness ranging approximately between the 1 nm and 20 nm. For example, the hole blocking layer 31 may have a thickness of about 5 nm. The thickness of the hole blocking layer 31 may be selected according to various application scenarios. The hole blocking layer 31 having a substantially thin thickness may be ineffective to block the hole movement, and the hole blocking layer 31 having a substantially thick thickness may not only block the hole movement, but also increase the operating voltage of the device.
The first electrode of the existing technology reference 1 may be made of indium tin oxide (ITO), and may have a thickness of about 150 nm. The hole injection layer may be made of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-diphenyl-4,4-diamine (NPB) doped with 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ). The F4-TCNQ material may have a doping ratio of about 3% by weight. The hole injection layer may have a thickness of about 10 nm. The hole transport layer may be made of NPB, and may have a thickness of about 50 nm.
The host material of the light-emitting layer may be 1,4-bis(5-p-tert-butylphenyl-1,3,4-oxadiazolyl-2)benzene (OXD-7). The guest material may be tris(2-phenylpyridine)iridium (Ir(PPY)3). Ir(PPY)3 may have a doping ratio of about 6% by weight. The light-emitting layer may have a thickness of about 25 nm. The electron transport layer may be made of 8-hydroxyquinoline aluminum (Alq3), and may have a thickness of about 40 nm. The electron injection layer may be made of LiF, and may have a thickness of about 1 nm. The second electrode may be made of Al, and may have a thickness of about 200 nm.
Further, the device of the existing technology reference 2 in
The first electrode of the existing technology reference 2 may be made of indium tin oxide (ITO), and may have a thickness of about 150 nm. The hole injection layer may be made of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-diphenyl-4,4-diamine (NPB) doped with 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ). The F4-TCNQ material may have a doping ratio of about 3% by weight. The hole injection layer may have a thickness of about 10 nm. The hole transport layer may be made of NPB, and may have a thickness of about 50 nm. The electron blocking layer may be made of 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), and may have a thickness of about 5 nm.
The host material of the light-emitting layer may be 1,4-bis(5-p-tert-butylphenyl-1,3,4-oxadiazolyl-2)benzene (OXD-7). The guest material may be tris(2-phenylpyridine)iridium (Ir(PPY)3). Ir(PPY)3 may have a doping ratio of about 6% by weight. The light-emitting layer may have a thickness of about 25 nm. The hole blocking layer may be made of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), and may have a thickness of about 5 nm. The electron transport layer may be made of 8-hydroxyquinoline aluminum (Alq3), and may have a thickness of about 40 nm. The electron injection layer may be made of LiF, and may have a thickness of about 1 nm. The second electrode may be made of Al, and may have a thickness of about 200 nm.
Referring to
In one embodiment, the first electrode may be made of indium tin oxide (ITO), and may have a thickness of about 150 nm. The hole injection layer may be made of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-diphenyl-4,4-diamine (NPB) doped with 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ). The F4-TCNQ material may have a doping ratio of about 3% by weight. The hole injection layer may have a thickness of about 10 nm.
The hole transport layer may be made of NPB, and may have a thickness of about 50 nm. The electron blocking layer may be made of 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), and may have a thickness of about 5 nm. The host material of the light-emitting layer may be 1,4-bis(5-p-tert-butylphenyl-1,3,4-oxadiazolyl-2)benzene (OXD-7), and the guest material may be tris(2-phenylpyridine)iridium (Ir(PPY)3). Ir(PPY)3 may have a doping ratio of about 6% by weight. The light-emitting layer may have a thickness of about 25 nm.
The host material of the hole blocking layer may be 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), and the guest material may be biphenyl-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD). The PBD material may have a doping ratio of about 10% by weight. The ratio of the electron mobility of the BCP material over the electron mobility of the PBD material may be equal to about 10. The hole blocking layer may have a thickness of about 5 nm. The electron transport layer may be made of 8-hydroxyquinoline aluminum (Alq3), and may have a thickness of about 40 nm. The electron injection layer may be made of LiF, and may have a thickness of about 1 nm. The second electrode may be made of Al, and may have a thickness of about 200 nm.
The skeletal structural formula of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-diphenyl-4,4-diamine (NPB) forming the hole injection layer is
The skeletal structural formula of 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ) forming the hole injection layer is
The skeletal structural formula of 1,4-bis(5-p-tert-butylphenyl-1,3,4-oxadiazolyl-2)benzene (OXD-7) forming the light-emitting layer is
The skeletal structural formula of tris(2-phenylpyridine)iridium (Ir(PPY)3) forming the light-emitting layer is
The skeletal structural formula of 8-hydroxyquinoline aluminum (Alq3) forming the electron transport layer is
The skeletal structural formula of 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC) forming the electron blocking layer is
The skeletal structural formula of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) forming the hole blocking layer is
The skeletal structural formula of biphenyl-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) forming the hole blocking layer is
Referring to
In the existing technology reference 2, because the electron blocking layer and the hole blocking layer are configured on both sides of the light-emitting layer, respectively, the balance of the electrons and holes in the device may be adjusted to certain degree, and an excessive number of electrons and holes passing through the limiting layer may be avoided. Thus, the relative luminance of the existing technology reference 2 may be attenuated slower than the relative luminance of the existing technology reference 1.
Further, the OLED display panel disclosed by the present disclosure may also be applicable to the electron-rich OLED display panel. Because the electron-rich OLED device is electron-rich, the excitons in the light-emitting layer may be located at the interface between the hole transport layer and the light-emitting layer. Thus, in the disclosed embodiments, through introducing an electron blocking layer and a hole blocking layer to the OLED display panel, and doping a guest material having a smaller electron mobility than the host material into the hole blocking layer, the electron movement may be reduced, the balance of the electrons and holes in the light-emitting layer may be adjusted, and the electron and hole recombination may be confined in the light-emitting layer. Accordingly, the efficiency of the organic electroluminescent device may be further improved.
Thus, the disclosed OLED display panel may be able to be operated at a relatively low operating voltage, leading to a slower attenuation of the relative luminance and a longer device life span. In addition, in the disclosed OLED display panel, the electron movement and the hole movement may be further balanced, the material deterioration may be suppressed, and the life span may be extended.
That is, the excitons may be prevented from being diffused to other regions outside the light-emitting layer. Thus, the exciton yield may be increased, the balance of the electrons and holes in the device may be adjusted, the electron and hole recombination may be confined in the light-emitting layer, a portion of the excitons formed by the electron and hole recombination may be prevented from being diffused to organic layers on both sides of the light-emitting layer and, accordingly, a higher external quantum efficiency may be achieved.
As shown in
In one embodiment, as shown in
Because the electrons and holes in the OLED device are often not balanced, for the electron-rich device, the electron and hole recombination may occur on the side of the light-emitting layer 20 close to the second electrode 40. As a result, the electrons and holes may be recombined in a narrow region. Under a high current density, the narrow region may have a substantially high exciton density. The excitons may interact with each other, causing triplet-triplet annihilation, and triplet-singlet annihilation, which, in turn, may reduce the exciton utilization rate. Thus, the efficiency of the OLED display panel may be decreased. At the same time, a large number of excitons accumulated in the narrow region may cause the material of the light-emitting layer to deteriorate, reducing the life span of the organic light-emitting display device.
In addition, in one embodiment, the electron blocking layer 51 may be doped with a first guest material D. In the electron blocking layer 51, the ratio of the hole mobility (μh_E) corresponding to the host material E over the hole mobility (μh_D) corresponding to the first guest material D may be configured to be greater than or equal to about 10. That is, the electron blocking layer 51 may be doped with the first guest material D having a smaller hole mobility (μh_D) than the host material E. Thus, the hole movement may be reduced, the balance of the electrons and holes in the device may be adjusted, the electron and hole recombination may be confined in the light-emitting layer 20, and the light-emitting efficiency and the life span of the OLED display panel may be increased.
In one embodiment, as shown in
The electron blocking layer 51 may include a hole transport type material. For example, the electron blocking layer 51 may include at least one of a carbazole type electron blocking material, and a triphenylamine type electron blocking material.
The host material E of the electron blocking layer 51 may include, for example, at least one of 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), and N,N′-bis-(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (TPD). The first guest material D of the electron blocking layer 51 may include, for example, at least one of N,N′-dicarbazolyl-3,5-benzene (mCP), 4,4′,4″-triscarbazolyl-triphenylamine (TCTA), and N,N′-bis(4-fluorophenyl)-N,N′-bis(3-methylphenyl)-9,9′-dimethylfluorence-2,7-diamine (X).
In one embodiment, the lowest unoccupied orbital level LUMOE of the host material E of the electron blocking layer 51 may be at least approximately 0.3 eV higher than the lowest unoccupied orbital level LUMOC of the host material C of the light-emitting layer 20, and the lowest unoccupied orbital level LUMOD of the first guest material D of the electron blocking layer 51 may be at least approximately 0.3 eV higher than the lowest unoccupied orbital level LUMOC of the host material C of the light-emitting layer 20, such that the electron blocking layer 51 may be effective in blocking the electron movement.
Similarly, the utilization rate of the triplet state excitons may be increased from the device structure perspective. After the triplet state excitons are generated in the light-emitting layer 20, through utilizing the higher triplet state energy level property of the hole blocking layer 31, the triplet state excitons in the light-emitting layer 20 may be prevented from being transported to other layers (e.g., the hole transport layer 52) outside the light-emitting layer 20. Thus, the exciton utilization rate of the device may be improved, and the light-emitting efficiency of the device may be increased.
The content of the host material E in the electron blocking layer 51 may be determined according to various application scenarios. In one embodiment, the content (i.e., weight percentage) of the host material E in the electron blocking layer 51 may be configured to be greater than or equal to about 90%. Provided that the content of the host material E effectively confine the electrons in the light-emitting layer 20, through doping the first guest material D into the host material E of the electron blocking layer 51, the hole injection rate into the light-emitting layer 20 may be reduced, and the electrons and holes in the light-emitting layer 20 may be balanced, such that the electrons and holes may be recombined in the center of the light-emitting layer 20. The exciton binding region may be widened, and the efficiency and life span of the device may be increased.
In one embodiment, the hole mobility of the host material E and the first guest material D in the electron blocking layer 51 may be configured to be 10−4 cm−2/V·S≤μh_E≤10−3 cm−2/V·S, and
respectively. The host material E and the first guest material D may be selected to satisfy the above relationship such that the efficiency and life span of the device may be increased.
For example, μh_E may be approximately 10−3 cm−2/V·S, and μh_D may be approximately 10−4 cm−2/V·S. The electron blocking layer 51 may have a thickness ranging approximately between the 1 nm and 20 nm. For example, the hole blocking layer 51 may have a thickness of about 5 nm. The thickness of the electron blocking layer 51 may be selected according to various application scenarios. The electron blocking layer 51 having a substantially thin thickness may be ineffective to block the electron movement, and the electron blocking layer 51 having a substantially thick thickness may not only block the electron movement, but also increase the operating voltage of the device.
The first electrode of the existing technology reference 1 may be made of indium tin oxide (ITO), and may have a thickness of about 150 nm. The hole injection layer may be made of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-diphenyl-4,4-diamine (NPB) doped with 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ). The F4-TCNQ material may have a doping ratio of about 3% by weight. The hole injection layer may have a thickness of about 10 nm. The hole transport layer may be made of NPB, and may have a thickness of about 50 nm.
The host material of the light-emitting layer may be 4,4′-bis(9-carbazole)biphenyl (CBP). The guest material may be tris(2-phenylpyridine) iridium (Ir(PPY)3). Ir(PPY)3 may have a doping ratio of about 6% by weight. The light-emitting layer may have a thickness of about 25 nm. The electron transport layer may be made of 8-hydroxyquinoline aluminum (Alq3), and may have a thickness of about 40 nm. The electron injection layer may be made of LiF, and may have a thickness of about 1 nm. The second electrode may be made of Al, and may have a thickness of about 200 nm.
Further, in
In one embodiment, the first electrode may be made of indium tin oxide (ITO), and may have a thickness of about 150 nm. The hole injection layer may be made of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-diphenyl-4,4-diamine (NPB) doped with 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ). The F4-TCNQ material may have a doping ratio of about 3% by weight. The hole injection layer may have a thickness of about 10 nm. The hole transport layer may be made of NPB, and may have a thickness of about 50 nm.
The host material of the electron blocking layer may be 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), and the guest material may be N,N′-bis(4-fluorophenyl)-N,N′-bis(3-methylphenyl)-9,9′-dimethylfluorence-2,7-diamine (X). The X material may have a doping ratio of about 10% by weight. The ratio of the hole mobility of TAPC over the hole mobility of X may be equal to about 27. The electron blocking layer may have a thickness of about 5 nm.
The host material of the light-emitting layer may be 4,4′-bis(9-carbazole)biphenyl (CBP), and the guest material may be tris(2-phenylpyridine) iridium (Ir(PPY)3). Ir(PPY)3 may have a doping ratio of about 6% by weight. The light-emitting layer may have a thickness of about 25 nm. The hole blocking layer may be made of 3,3′-[5′-[3-(3-pyridinyl)phenyl][1,1′:3′,1″-terpheny1]-3,3″-diy1]bispyridine (TmPyPB), and may have a thickness of about 5 nm. The electron transport layer may be made of 8-hydroxyquinoline aluminum (Alq3), and may have a thickness of about 40 nm. The electron injection layer may be made of LiF, and may have a thickness of about 1 nm. The second electrode may be made of Al, and may have a thickness of about 200 nm.
The skeletal structural formula of 4,4′-bis(9-carbazole)biphenyl (CBP) forming the light-emitting layer is
The skeletal structural formula of 3,3′-[5′-[3-(3-pyridinyl)phenyl][1,1′:3′,1″-terpheny1]-3,3″-diy1]bispyridine (TmPyPB) forming the hole blocking layer is
The skeletal structural formula of N,N′-bis(4-fluorophenyl)-N,N′-bis(3-methylphenyl)-9,9′-dimethylfluorence-2,7-diamine (X) forming the electron blocking layer is
The skeletal structural formula of N,N′-bis-(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (TPD) forming the electron blocking layer is
The skeletal structural formula of N,N′-dicarbazolyl-3,5-benzene (mCP) forming the electron blocking layer is
The skeletal structural formula of 4,4′,4″-triscarbazolyl-triphenylamine (TCTA) forming the electron blocking layer is
Other organic function materials may have the skeletal structural formula as previously described.
Referring to
As shown in
In one embodiment, an electron blocking layer and a hole blocking layer may be configured on both sides of the light-emitting layer, respectively, to avoid excessive number of electrons and holes passing through the light-emitting layer. In addition, a guest material having a smaller hole mobility than the host material may be doped into the electron blocking layer. For the hole-rich OLED device, the electron movement may be reduced, the balance of the electrons and holes in the light-emitting layer may be adjusted, and the electron and hole recombination may be confined inside the light-emitting layer. Accordingly, the efficiency of the organic electroluminescent device may be further improved.
Thus, the disclosed OLED display panel may be operated at a relatively low operating voltage, leading to a slower attenuation of the relative luminance, and a longer device life span. In addition, in the disclosed OLED display panel, the electron movement and the hole movement may be further balanced, the material deterioration may be suppressed, and the life span may be extended.
Because the OLED display panel according to the present disclosure may have the electron blocking layer and the hole blocking layer disposed on both sides of the light-emitting layer, respectively, excessive electrons and holes may be prevented from passing through the light-emitting layer. Thus, the energy of the electrons and holes may be fully unitized to stimulate the light emitting in the light-emitting material. Accordingly, the reduction of the efficiency and life span of the OLED display panel, which is caused by the insufficient usage of the energy of the electrons and holes, may be prevented.
In addition, in one embodiment, for the hole-rich device, because the electron blocking layer is doped with a guest material having a smaller hole mobility than the host material, the hole movement may be reduced, and the balance of the electrons and holes in the OLED display panel may be adjusted. Thus, the external quantum efficiency of the disclosed OLED display panel may be greater than the external quantum efficiency of the existing technology reference 1.
In the disclosed embodiments, an electron blocking layer and a hole blocking layer may be disposed on both sides of the light-emitting layer, respectively. The electron blocking layer may be configured to block an excessive number of the electrons from transporting to the hole transport layer. The hole blocking layer may be configured to block an excessive number of the holes from transporting to the electron transport layer. Certain examples are shown in
The OLED display panels shown in
In certain embodiments, either an electron blocking layer or a hole blocking layer may be configured on only one side of the light-emitting layer, and the electron blocking layer or the hole blocking layer may be doped with a guest material having a desired carrier mobility. Certain examples are shown in
In particular, the hole blocking later 61 may be disposed between the light-emitting layer 20 and the second electrode 40, such that an excessive number of holes may be prevented from passing through the light-emitting layer 20 to reach the second electrode 40, and the holes may be effectively confined in the light-emitting layer 20. The electron blocking layer 71 may be disposed between the light-emitting layer 20 and the first electrode 10, such that excessive electrodes may be prevented from passing through the light-emitting layer 20 to reach the first electrode 10, and the electrons may be effectively confined in the light-emitting layer 20. Thus, the exciton yield may be increased, and the light-emitting efficiency of the OLED display panel may be increased.
In one embodiment, the hole blocking layer 61 may be doped with a first guest material A. In the hole blocking layer 61, the ratio of the electron mobility μe_B corresponding to the host material B over the electron mobility μe_A corresponding to the first guest material A may be configured to be greater than or equal to about 10. That is, the hole blocking layer 61 may be doped with the first guest material A having a smaller electron mobility μe_A than the host material B. Thus, the electron movement may be reduced, the rate of the electron injection into the light-emitting layer 20 may be reduced, and the exciton binding region may be moved away from the interface of the light-emitting layer 20 adjacent to the first electrode 10.
In one embodiment, the electron blocking layer 71 may be doped with a second guest material D. In the electron blocking layer 71, the ratio of the hole mobility μh_E corresponding to the host material E over the hole mobility μh_D corresponding to the second guest material D may be configured to be greater than or equal to about 10. That is, the electron blocking layer 71 may be doped with the second guest material D having a smaller hole mobility μh_D than the host material E. Thus, the hole movement may be reduced, the rate of the hole injection into the light-emitting layer 20 may be reduced, and the exciton binding region may be moved away from the interface of the light-emitting layer 20 adjacent to the second electrode 40.
Thus, in the disclosed OLED display panel, a portion of the excitons formed by the electron and hole recombination may be prevented from diffusing toward both sides of the light-emitting layer 20, the balance of the electrons and holes in the light-emitting layer 20 may be adjusted, the electron and hole recombination may occur in the center of the light-emitting layer 20, the exciton binding region may be widened, and the efficiency and the life span of the OLED display panel may be improved.
In addition, in one embodiment, the highest occupied orbital level HOMOB of the host material B of the hole blocking layer 61 may be at least approximately 0.3 eV higher than the highest occupied orbital level HOMOC of the host material C of the light-emitting layer 20, and the highest occupied orbital level HOMOA of the first guest material A of the hole blocking layer 61 may be at least approximately 0.3 eV higher than the highest occupied orbital level HOMOC of the host material C of the light-emitting layer 20, such that the hole blocking layer 61 may be effective in blocking hole movement.
The triplet state energy level TB of the host material B of the hole blocking layer 61 may be configured to be greater than the triplet state energy level TC of the host material C of the light-emitting layer 20, and the triplet state energy level TA of the first guest material A of the hole blocking layer 61 may be configured to be greater than the triplet state energy level TC of the host material C of the light-emitting layer 20, which may improve the utilization rate of the triplet state excitons from the device structure perspective.
At the same time, the highest occupied orbital level HOMOE of the host material E of the electron blocking layer 71 may be at least approximately 0.3 eV higher than the highest occupied orbital level HOMOC of the host material C of the light-emitting layer 20, and the highest occupied orbital level HOMOD of the second guest material D of the electron blocking layer 71 may be at least approximately 0.3 eV higher than the highest occupied orbital level HOMOC of the host material C of the light-emitting layer 20, such that the electron blocking layer 71 may be effective in blocking electron movement.
Similarly, the utilization rate of the triplet state excitons may be improved from the device structure perspective. After the triplet state excitons are generated in the light-emitting layer 20, through utilizing the higher triplet state energy level property of the electron blocking layer 71, the triplet state excitons in the light-emitting layer 20 may be prevented from being transported to other layers (e.g., the hole transport layer 52) outside the light-emitting layer 20. Thus, the exciton utilization rate of the device may be improved, and the light-emitting efficiency of the device may be increased.
The content of the host material B in the hole blocking layer 61 may be configured to be greater than or equal to about 90%. The content of the host material E in the electron blocking layer 71 may be configured to be greater than or equal to about 90%.
In one embodiment, the electron mobility μe_B of the host material B in the hole blocking layer 61 may be configured to be greater than or equal to about 10−4 cm−2/V·S, and less than or equal to 10−3 cm−2/V·S. The electron mobility μe_A of the first guest material A in the hole blocking layer 61 may be configured to be less than or equal to about 10−4 cm−2/V·S. The hole mobility μh_E of the host material E in the electron blocking layer 71 may be configured to be greater than or equal to about 10−4 cm−2/V·S, and less than or equal to 10−3 cm−2/V·S. The hole mobility μh_D of the second guest material D in the electron blocking layer 71 may be configured to be less than or equal to about 10−4 cm−2/V·S. The hole blocking layer 61 may have a thickness ranging approximately between 1 nm and 20 nm. The electron blocking layer 71 may have a thickness ranging approximately between 1 nm and 20 nm.
Optionally, the first function layer 60 may also include at least one of an electron injection layer 63, and an electron transport layer 62. Referring to
In one embodiment, the OLED display panel disclosed by the present disclosure may include a plurality of pixel regions emitting light of different colors. For example, in
In one embodiment, the light-emitting layer 20 may include a host material and a guest material. At least one of the light-emitting layer 20 corresponding to the red light-emitting pixel region R and the light-emitting layer 20 corresponding to the blue light-emitting pixel region B may be made of one or two host materials. The light-emitting layer 20 corresponding to the green light-emitting pixel region G may be made of at least two host materials.
In the light-emitting layer 20, the host material content may be more than the guest material content. Generally, the absolute value of a HOMO energy level |Thost(HOMO)| of the host material may be greater than the absolute value of a HOMO energy level |Tdopant(HOMO)| of the guest material, the absolute value of a LUMO energy level |Thost(LUMO)| of the host material may be smaller than the absolute value of a LUMO energy level |Tdopant(LUMO)| of the guest material, and a triplet state energy level Thost(S) of the host material may be greater than a triplet state energy level Tdopant(S) of the guest material. The triplet state energy of the host material may be effectively transferred to the guest material, and the light emission spectrum of the host material may match the light absorption spectrum of the guest material.
In addition, the guest material of the light-emitting layer 20 may include a phosphorescent or fluorescent material. For example, the guest material of the light-emitting layer 20 corresponding to the red light-emitting pixel region R and the green light-emitting pixel region G may be a phosphorescent material, and the guest material of the light-emitting layer 20 corresponding to the blue light-emitting pixel region B may be a fluorescent material. The material of the light-emitting layer 20 is not limited by the present disclosure. For example, the light-emitting layer 20 may be made of a material other than the host-guest dopant structure or made of a thermally activated delayed fluorescent (TADF) material.
In certain embodiments, a micro-cavity structure may be formed between a first electrode and a second electrode of a pixel region in the OLED display panel. The cavity length of the micro-cavity structure corresponding to the pixel region may be positively correlated with the wavelength of the emission color corresponding to the pixel region. The cavity length of the micro-cavity structure may be a distance between the first electrode and the second electrode of the pixel region. The micro-cavity structure may confine the light in a substantially small wavelength band by effects of reflection, total reflection, interference, diffraction, and scattering on the discontinuous interfaces of refractive index.
By designing the cavity length and the thickness of each layer in the micro-cavity structure, the wavelength center of the emission light may be located near an enhancement peak of the standing wave field, which may increase a coupling efficiency between a radiation dipole and an electric field in the cavity, thereby improving the light-emitting efficiency and brightness of the OLED display panel. The cavity length of the micro-cavity structure may be adjusted by adjusting the thicknesses of individual layers of the first function layer, the thickness of the light-emitting layer, and the thicknesses of individual layers of the second function layer.
The present disclosure also provides an electronic device.
The present disclosure also provides a manufacturing method for the OLED display panel.
For example, the first electrode 10 may be a reflective electrode made of a metal alloy containing Ag or Mg, or a transparent electrode made of indium tin oxide or indium zinc oxide.
In certain embodiments, after the first electrode 10 is formed, a pixel defining layer (not shown in
In certain other embodiments, before the first electrode 10 is formed, a pixel defining layer may be formed. The pixel defining layer may include a plurality of opening structures. Then, the first electrode 10 may be formed in each opening structure. The pixel defining layer may prevent undesired color mixing in the subsequently formed light-emitting layer 20.
Returning to
For the light-emitting regions of different emission colors, the light-emitting layer 20 may be sequentially deposited by using masks. In certain embodiments, the thicknesses of the light-emitting layers corresponding to the light-emitting regions of different emission colors may be the same. In certain other embodiments, the thicknesses of the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors may be different.
The thicknesses of the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors may be determined according to various factors, such as the actual manufacturing requirements, the micro-cavity structures corresponding to the light-emitting regions of different emission colors, light-emitting layer characteristics, and the transport balances between holes and electrons in different light-emitting regions, etc., as long as through adjusting the cavity lengths of the corresponding micro-cavity structures, the light emitted from the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors may be enhanced by the constructive interference, i.e. the brightness may be increased.
Returning to
As shown in
Returning to
For example, the second electrode 40 may be made of a metal, such as Ag, or made of a transparent metal oxide, such as indium tin oxide.
In certain embodiments, a first-type blocking layer may be formed between the light-emitting layer 20 and the second electrode 40, such that an excessive number of first-type carriers may be prevented from passing through the light-emitting layer 20 to reach the side of the light-emitting layer 20 facing away from the first electrode 10. The first-type blocking layer may prevent the excitons from diffusing into layers other than the light-emitting layer 20, thereby increasing the exciton yield and the light-emitting efficiency of the OLED display panel.
In addition, a guest material may be doped in the first-type blocking layer, in which the ratio of the second-type carrier mobility of the host material over the second-type carrier mobility of the first guest material may be configured to be greater than or equal to about 10. That is, a guest material having a smaller second-type carrier mobility than the host material may be doped in the first-type blocking layer. For second-type-carrier-rich devices, the guest material may reduce the movement of the second-type carriers, and may move the exciton recombination region away from the interface of the light-emitting layer 20 adjacent to the first electrode 10. Thus, the excitons formed by the electron and hole recombination may be prevented from diffusing to both sides of the light-emitting layer, and the efficiency of the OLED display panel may be improved.
In certain other embodiments, the OLED display panel may be formed by sequentially forming a second electrode 40, a first function layer 30 and 50, a light-emitting layer 20, and a first electrode 10.
In the disclosed embodiments, when the first electrode 10 in the OLED display panel is an anode, the second electrode 40 is a cathode, the first-type is a hole-type, and the second-type is an electron-type, the following conditions may be satisfied: TB>TC, TA>TC, HOMOB−HOMOC≥0.3 eV, and HOMOA−HOMOC≥0.3 eV, where TB is the triplet state energy level of the host material B of the first-type blocking layer, TC is the triplet state energy level of the host material C of the light-emitting layer 20, TA is the triplet state energy level of the first guest material A of the first-type blocking layer, HOMOB is the highest occupied molecular orbital energy level of the host material B of the first-type blocking layer, HOMOC is the highest occupied molecular orbital energy level of the host material C of the light-emitting layer 20, and HOMOA is the highest occupied molecular orbital energy level of the first guest material A of the first-type blocking layer.
Both the host material B and the first guest material A in the hole blocking layer have a higher triplet state energy level than the host material C in the light-emitting layer 20, such that the excitons formed by the electron and hole recombination may be prevented from diffusing to organic layers other than the light-emitting layer 20 and, accordingly, the efficiency of the OLED device may be improved.
In certain embodiments, when the first-type is a hole-type, and the second-type is an electron-type, the host material B of the first-type blocking layer may include at least one of 3,3′-[5′-[3-(3-pyridinyl)phenyl][1,1′:3′,1″-terpheny1]-3,3″-diy1]bispyridine (TmPyPB), 4,4-bis(9-carbazolyl)-1,1′-biphenyl (BCP), 4,6-bis(3,5-di(pyridine-4-yl)phenyl)-2-MethylpyriMidine (B4PyMPM), star oxadiazole, and 1,3,5-tris(N-phenyl-2-benzimidazole) benzene (TPBi). The first guest material A of the first-type blocking layer may include at least one of 8-hydroxyquinoline aluminum (Alq3), 8-hydroxyquinoline lithium (Liq), 2-(4-biphenyl)-5-phenyl oxadiazole (PBD), 2,5-bis-(4-naphthyl)-1,3,4-oxadiazole (BND), tris-(2,3,5,6-trimethyl)phenylboron, and 2,5-diaryl silicon.
In the disclosed embodiments, when the first electrode 10 is a cathode, the second electrode 40 is an anode, the first-type is an electron-type, and the second-type is a hole-type, the following conditions may be configured: TE>TC, TD>TC, LUMOE−LUMOC≥0.3 eV, and LUMOD−LUMOC≥0.3 eV. TE is the triplet state energy level of the host material E of the first-type blocking layer, TC is the triplet state energy level of the host material C of the light-emitting layer 20, TD is the triplet state energy level of the first guest material D of the first-type blocking layer, HOMOE is the highest occupied molecular orbital energy level of the host material E of the first-type blocking layer, HOMOC is the highest occupied molecular orbital energy level of the host material C of the light-emitting layer 20, and HOMOD is the highest occupied molecular orbital energy level of the first guest material D of the first-type blocking layer.
Both the host material E and the first guest material D in the hole blocking layer have a higher triplet state energy level than the material C in the light-emitting layer 20, such that a portion of the excitons formed by the electron and hole recombination may be prevented from diffusing to organic layers other than the light-emitting layer 20, which is desired for improving the efficiency of the OLED device.
In certain other embodiments, when the first-type is an electron-type, and the second-type is a hole-type, the host material E of the first-type blocking layer may include at least one of 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), and N,N′-bis-(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (TPD). The first guest material D of the first-type blocking layer may include at least one of N,N′-dicarbazolyl-3,5-benzene (mCP), 4,4′,4″-triscarbazolyl-triphenylamine (TCTA), and N,N′-bis(4-fluorophenyl)-N,N′-bis(3-methylphenyl)-9,9′-dimethylfluorence-2,7-diamine (X).
In certain embodiments, as shown in
Further, a second guest material may be doped in the second-type blocking layer, in which the ratio of the first-type carrier mobility of the host material over the first-type carrier mobility of the second guest material may be configured to be greater than or equal to about 10. Thus, the balance of the electron and hole movement in the OLED display panel may be improved, the carrier recombination region may be confined near to the light-emitting layer 20, the excitons formed by the electron and hole recombination may be prevented from diffusing toward both sides of the light-emitting layer 20, and the efficiency of the OLED device may be increased. A flow chart of a corresponding manufacturing method is shown in
A shown in
In certain embodiments, after the first electrode 10 is formed, a pixel defining layer (not shown in
In certain other embodiments, before the first electrode 10 is formed, a pixel defining layer (not shown in
Returning to
A shown in
Returning to
As shown in
The thicknesses of the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors may be determined according to various factors, such as the actual manufacturing requirements, the micro-cavity structures corresponding to the light-emitting regions of different emission colors, light-emitting layer characteristics, and the transport balances between holes and electrons in different light-emitting regions, etc., as long as, through adjusting the cavity lengths of the corresponding micro-cavity structures, the light emitted from the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors can be enhanced by a constructive interference.
Returning to
As shown in
Returning to
As shown in
In another embodiment, the second electrode may be formed on the substrate first, then the first function layer, the light-emitting layer, the second function layer and the first electrode may be sequentially formed on the second electrode. A flow chart of the corresponding manufacturing method is shown in
As shown in
In certain embodiments, after the second electrode 40 is formed, a pixel defining layer (not shown in
In certain other embodiments, before the second electrode 40 is formed, a pixel defining layer may be formed. The pixel defining layer may include a plurality of opening structures. Then, a second electrode 40 may be formed in each opening structure. The pixel defining layer may prevent undesired color mixing of the subsequently formed light-emitting layer 20.
Returning to
As shown in
Returning to
As shown in
The thicknesses of the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors may be determined according to various factors, such as the actual manufacturing requirements, the micro-cavity structures corresponding to the light-emitting regions of different emission colors, light-emitting layer characteristics, and the transport balances between holes and electrons in different light-emitting regions, etc., as long as, through adjusting the cavity lengths of the corresponding micro-cavity structures, the light emitted from the light-emitting layers 20 corresponding to the light-emitting regions of different emission colors can be enhanced by a constructive interference.
Returning to
As shown in
Returning to
As shown in
In certain embodiments, the content of the host material in the first-type blocking layer and the second-type blocking layer may be configured to be greater than or equal to about 90%. The first function layer 60 may also include at least one of a first-type injection layer, and a first-type transport layer. The second function layer 70 may also include at least one of a second-type injection layer, and a second-type transport layer. The first-type blocking layer and the second-type blocking layer may have a thickness ranging approximately between 1 nm and 20 nm.
In certain embodiments, the second-type carrier mobility of the host material in the first-type blocking layer may be configured to be greater than or equal to about 10−4 cm−2/V·S, and less than or equal to 10−3 cm−2/V·S. The second-type carrier mobility of the first guest material in the first-type blocking layer may be configured to be less than or equal to about 10−4 cm−2/V·S. The first-type carrier mobility of the host material in the second-type blocking layer may be configured to be greater than or equal to about 10−4 cm−2/V·S, and less than or equal to 10−3 cm−2/V·S. The first-type carrier mobility of the second guest material in the second-type blocking layer may be configured to be less than or equal to about 10−4 cm−2/V·S.
In certain embodiments, the first-type blocking layer having a doped structure may be adopted to adjust the carrier balance, confine the exciton recombination region in the light-emitting layer, prevent a portion of the excitons formed by electron and hole recombination from diffusing to other layers on both sides of the light-emitting layer, and increase the efficiency and life span of the OLED device.
As described above, the present disclosure provides an OLED display panel, an electronic device, and a manufacturing method. The disclosed OLED display panel may include at least a first electrode, a light-emitting layer, a first function layer, and a second electrode, which are disposed in stacked layers. The first function layer may include at least a first-type blocking layer. The first-type blocking layer may be disposed adjacent to the light-emitting layer. The first-type blocking layer may be doped with a first guest material.
In the first-type blocking layer, the ratio of the second-type carrier mobility of the host material over the second-type carrier mobility of the first guest material may be configured to be greater than or equal to about 10, thereby improving the light-emitting efficiency and life span of the OLED display panel.
Various embodiments have been described to illustrate the operation principles and exemplary implementations. It should be understood by those skilled in the art that the present invention is not limited to the specific embodiments described herein and that various other obvious changes, rearrangements, and substitutions will occur to those skilled in the art without departing from the scope of the invention. Thus, while the present invention has been described in detail with reference to the above described embodiments, the present invention is not limited to the above described embodiments, but may be embodied in other equivalent forms without departing from the scope of the present invention, which is determined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201611168770.2 | Dec 2016 | CN | national |
This application is a divisional of U.S. patent application Ser. No. 15/464,701, filed on Mar. 21, 2017, which claims the priority of Chinese Patent Application No. CN201611168770.2, filed on Dec. 16, 2016, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15464701 | Mar 2017 | US |
| Child | 17237873 | US |
