This application claims priority of Chinese Patent Application No. 201611155175.5, filed on Dec. 14, 2016, the entire contents of which are hereby incorporated by reference.
The present disclosure generally relates to the field of organic light-emitting diode (OLED) display technology and, in particular, relates to an OLED display panel and a display apparatus thereof.
OLED displays have become one of the most important trends in the display industry, because of their various technological advantages, such as working without a backlight source, high contrast ratio, thin thickness, wide viewing angle and fast response. An existing OLED display panel comprises a cathode, an electron transport layer, a light-emitting layer, a hole transport layer, an anode and a substrate. In operation, a bias voltage is applied between the cathode and the anode. As a result, holes and electrons pass through the interface barrier, and respectively migrate from the hole transport layer and the electron transport layer towards the light-emitting layer where electrons and holes further recombine to form excitons.
The formed excitons are substantially unstable, which release and transfer the energy to organic luminescent molecules in the light-emitting layer. The transferred energy leads to the energetical transition in the organic luminescent molecules from the ground state to the excited state. The light emission is consequently generated from the luminescent molecules by the spontaneous radiation decay from the excited state back to the ground state.
In the existing OLED display panel, the interface barrier between the organic material and the electrode often determines the number of injected carriers, panel brightness and efficiency. However, the interface barrier between the electron transport layer and the cathode may be substantially high in the existing OLED display panels, resulting in the limited capability of electron injection and, accordingly, the poor performance of OLED display panel.
The disclosed OLED display panel and OLED display apparatus thereof 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. The OLED display panel comprises: a substrate; a first electrode and a second electrode disposed in a slacked configuration and on a same side of the substrate; an organic luminescent layer disposed between the first electrode and the second electrode; and an electron transport layer, disposed between the organic luminescent layer and the second electrode and including a predetermined volume percent age of element ytterbium (Yb).
Other aspects of the present disclosure can he 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 invention, which are illustrated in the accompanying drawings. Hereinafter, embodiments consistent with the disclosure will be described with reference to drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. It is apparent that the described embodiments are some but not all of the embodiments of the present invention. Based on the disclosed embodiments, persons of ordinary skill in the art may derive other embodiments consistent with the present disclosure, all of which are within the scope of the present invention. Further, in the present disclosure, the disclosed embodiments and the features of the disclosed embodiments may be combined under conditions without conflicts.
The present disclosure provides an improved OLED display panel capable of reducing the interface barrier between the electron transport layer and the cathode and, thus, improving the display performance.
In particular, the first electrode 11 and the second electrode 12 may be both disposed on the same side of the substrate 10. The organic luminescent layer 13 may be disposed between the first electrode 11 and the second electrode 12. The electron transport layer 14 may be disposed between the organic luminescent layer 13 and the second electrode 12.
The electron transport layer 14 may include active metals, such as alkali metals, alkaline earth metals, or rare-earth metals, or active metals doped with organic materials. The active metals may he sandwiched between the electron transport layer 14 and the cathode. In one embodiment the electron transport layer 14 may contain an element of ytterbium (Yb), which is one of the rare-earth metals with atomic number 70 in the lanthanide series of the periodic tables. The volume percentage of element Yb may be equal to or less than approximately 3%. The first electrode 11 and the second electrode 12 may be an anode and a cathode, respectively.
According to the Fowler-Nordheim tunneling model, the element Yb in the electron transport layer 14 may reduce the interfacial energy barrier (i.e., interface barrier) between the second electrode 12 and the electron transport layer 14. In the existing OLED display panels, the electron transport layer 14 may not contain the element Yb.
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That is, the operation time of the disclosed OLED display panel D may be much longer than the operation time of the existing OLED display panel C, indicating that the disclosed OLED display panel D may have a longer lifetime than the existing OLED display panel C. In other words, the element Yb introduced into the electron transport layer 14 may prolong the lifetime of the OLED display panel.
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In summary, the OLED display panels provided with different volume percentages of element Yb in the electron transport layer 14 may differ in the performance, in practical applications, the volume percentage of element Yb may be adjusted based on the various performance requirements of the OLED display panel. In one embodiment, the volume percentage of the element Yb maybe configured to be equal to or less than 3% (i.e., ≦3%).
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The respective layers of the first electrode 11 may have various materials and thicknesses according to various application scenarios, provided that the first electrode 11 has a desired hole injection capability and a desired light reflectivity. For example, in one embodiment, both the first transparent conductive film 111 and the second transparent conductive film 112 in the first electrode 11 may be composed of indium tin oxide or indium zinc oxide, and the reflective film 113 may be composed of silver or silver-based alloy. The thickness of the reflective film 113 may range from approximately 50 nm to 150 nm.
Similarly, the thickness of the second electrode 12 may also vary according to various application scenarios, provide that the second electrode 12 has a desired electron injection capability and a desired light transmittance. For example, in one embodiment, the second electrode 12 may be composed of silver-based alloy, the volume percentage of silver may be equal to or larger than approximately 80%, and the thickness of the second electrode 12 may range from approximately 10 nm to 20 nm.
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The materials and thicknesses of the first electrode 11 may vary according to various application scenarios, provided that the first electrode has a desired hole injection capability and a desired light transmittance. For example, in one embodiment, the first electrode 11 may be composed of indium tin oxide or indium zinc oxide.
Similarly, the materials and thicknesses of the second electrode 12 may also vary according to various application scenarios, provided that the second electrode 12 has a desired electron injection capability and a desired reflectivity. For example, in one embodiment, the second electrode 12 may he composed of a silver-based, alloy, in which the volume percentage of silver is equal to or larger than approximately 80%, and the thickness of the second electrode may vary between approximately 50 nm and 150 nm.
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The materials and thicknesses of the first electrode 11 may vary according to various application scenarios, provided that the first electrode has a desired hole injection capability and a desired light transmittance. For example, in one embodiment, the first electrode 11 may be composed of indium tin oxide or indium zinc oxide.
Similarly, the materials and thicknesses of the second electrode 12 may also vary according to various application scenarios, provided that the second electrode 12 has a desired electron injection capability and a desired reflectivity. For example, in one embodiment, the second electrode 12 may be composed of a silver-based alloy, in which the volume percentage of silver may be equal to or larger than approximately 80%, and the thickness of the second electrode may vary between approximately 50 nm and 150 nm.
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In particular, the first electrode may include a first transparent conductive film 111, a second transparent conductive film 112, and a reflective film 113 sandwiched between the first transparent conductive film 111 and the second transparent conductive film 112. The second electrode 12 may include metals or metal alloys, such as silver or a silver-based alloy.
The respective layers of the first electrode 11 may have various materials and thicknesses according to various application scenarios, provided that the first electrode 11 has a desired hole injection capability and a desired light reflectivity. For example, in one embodiment, both the first transparent conductive film 111 and the second transparent conductive film 112 in the first electrode 11 may be composed of indium tin oxide or indium zinc oxide, and the reflective film 113 may be composed of silver or silver-based alloy. The thickness of the reflective film 113 may range from approximately 50 nm to 150 nm.
Similarly, the thickness of the second electrode 12 may also vary according to various application scenarios, provide that the second electrode 12 has a desired electron injection capability and a desired light transmittance. For example, in one embodiment, the second electrode 12 may be composed of silver-based alloy, in which the volume percentage of silver may be equal to or larger than approximately 80%. The thickness of the second electrode 12 may range from approximately 10 nm to 20 nm.
In one embodiment, the OLED display panel may be a double-side emission OLED display panel in which both the first electrode 11 and the second electrode 12, disposed at the two sides of the panel, may be the light-output-side electrode. That is, the light generated in the organic luminescent layer 13 may be emitted from the top after passing through the first electrode 11 and, meanwhile, may be emitted from the bottom after sequentially passing through the electron transport layer 14, the second electrode 12 and the substrate 10.
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Furthermore, the organic luminescent layer 13 may include organic luminescent materials for realizing, white illumination. In one embodiment, the organic luminescent layer 13 may include a red light-emitting material a green light-emitting material and a blue light-emitting material. White light emission may be obtained by mixing the light emitted from the red, green and blue light-emitting materials.
When the organic luminescent layer 13 may include a red light-emitting material, a green light-emitting material and a blue light-emitting material, the red light-emitting material, the green light-emitting material and the blue light-emitting material may vary according to various application scenarios. For example, in one embodiment, the red light-emitting materials and the green light-emitting materials may contain phosphorescent materials. The blue light-emitting materials may contain fluorescent materials, and the fluorescent materials may include thermally activated delayed fluorescent materials.
In addition, the red, the green, and the blue light-emitting materials may include host materials doped with guest materials. In one embodiment, the red light-emitting materials may comprise one host material or two host materials, the green light-emitting materials may comprise at least two host materials, and the blue-emitting materials may comprise one host material or two host materials.
The present disclosure also provides an OLED display apparatus.
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Through introducing the element Yb with a volume percentage equal to or less than 3% into the electron transport layer 14, the disclosed OLED display panels and the OLED display apparatus may solve the problems of the substantially high interface barrier between the cathode and the electron transport layer 14 as well as the poor display performance. That is, the disclosed OLED display panels and OLED display apparatus may be able to reduce the substantially high interface barrier between the cathode and the electron transport layer 14, improve the electron injection capability and, accordingly, enhance the display performance.
The description of the disclosed embodiments is provided to illustrate the present invention to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Number | Date | Country | Kind |
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201611155175.5 | Dec 2016 | CN | national |