Organic light-emitting transistor, manufacturing method thereof, display panel and display device

Abstract

This disclosure relates to an organic light-emitting transistor (OLED) and its fabrication method, a display panel, and a display device. At least a portion of a first micro / nano grating structure (71) is provided on the side of the electron transport layer (7) away from the substrate (1), such that at least a portion of a second micro / nano grating structure (82) is formed on the side of the first electrode (8) away from the substrate (1). The first micro / nano grating structure (71) and the second micro / nano grating structure (82) can reduce the wave vector within the waveguide effect surface, thereby effectively reducing the in-plane wave vector. When the in-plane wave vector is less than the wave vector in free space, the excited plasma mode is converted into an emissive mode, effectively extracting the emitted light. This effectively reduces energy loss caused by the OLED surface plasma mode and improves the OLED's luminous efficiency.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, in particular, to an organic light emitting transistor, a manufacturing method thereof, a display panel and a display device. BACKGROUND

[0002] An organic light emitting transistor (OLET) integrates the switching function of an organic field effect transistor (OFET) and the electroluminescence function of an organic light emitting diode (OLED), has the characteristics of simple structure, light and thin device, easy miniaturization, etc., and becomes one of the development trends of future display technology.

[0003] However, a large proportion of the external quantum extraction efficiency of the organic light emitting transistor is still limited or lost inside, which cannot be effectively utilized, affecting the light emitting efficiency of the organic light emitting transistor and limiting the performance of the organic light emitting transistor.

[0004] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present disclosure is to overcome the shortcomings of the prior art, and to provide an organic light emitting transistor, a manufacturing method thereof, a display panel and a display device.

[0006] According to one aspect of the present disclosure, an organic light emitting transistor is provided, comprising a substrate, an active layer, a hole transport layer, a light emitting layer, an electron transport layer and a first electrode; the active layer is arranged on one side of the substrate; the hole transport layer is arranged on the side of the active layer away from the substrate; the light emitting layer is arranged on the side of the hole transport layer away from the substrate; the electron transport layer is arranged on the side of the light emitting layer away from the substrate, and at least part of a first micro-nano grating structure is arranged on the side of the electron transport layer away from the substrate; the first electrode is arranged on the side of the electron transport layer away from the substrate, and at least part of a second micro-nano grating structure is arranged on the side of the first electrode away from the substrate, and the orthographic projection of the second micro-nano grating structure on the substrate is located within the orthographic projection of the first micro-nano grating structure on the substrate.

[0007] In one embodiment of the present disclosure, the electron transport layer has a first region and a second region arranged at intervals on the side away from the substrate, the first micro-nano grating structure is located in the first region, the first electrode is arranged on the first micro-nano grating structure, the second region is provided with a third micro-nano grating structure, the organic light-emitting transistor further comprises a second electrode, the second electrode is arranged on the third micro-nano grating structure, and the side of the second electrode away from the substrate is provided with a fourth micro-nano grating structure, and the fourth micro-nano grating structure is located in the projection of the second micro-nano grating structure on the substrate.

[0008] In one embodiment of the present disclosure, the region of the electron transport layer between the first electrode and the second electrode on the side away from the substrate is a planar region.

[0009] In one embodiment of the present disclosure, the first micro-nano grating structure, the second micro-nano grating structure, the third micro-nano grating structure and the fourth micro-nano grating structure are all periodic micro-nano grating structures, and the periodic micro-nano grating structure comprises a plurality of parallel strip-shaped grooves, the widths of the strip-shaped grooves are equal, and the distances between adjacent two grooves are equal.

[0010] In one embodiment of the present disclosure, in the direction perpendicular to the extension direction of the strip-shaped grooves, the cross-sectional shape of the strip-shaped grooves is rectangular or arc-shaped.

[0011] In one embodiment of the present disclosure, when the cross-sectional shape of the strip-shaped grooves is rectangular, the width of the strip-shaped grooves is 200-600 nm, the depth is 10-50 nm, and the distance between adjacent two strip-shaped grooves is 5-50 nm.

[0012] In one embodiment of the present disclosure, the first micro-nano grating structure, the second micro-nano grating structure, the third micro-nano grating structure and the fourth micro-nano grating structure are all periodic micro-nano grating structures, and the periodic micro-nano grating structure comprises a plurality of dot-shaped recesses arranged in an array.

[0013] In one embodiment of the present disclosure, the organic light-emitting transistor further comprises a first gate electrode, the first gate electrode is arranged between the substrate and the active layer, and a first insulating layer is arranged between the first gate electrode and the active layer.

[0014] In one embodiment of the present disclosure, the organic light-emitting transistor further comprises a second gate electrode, the second gate electrode is arranged between the first insulating layer and the active layer, and a second insulating layer is arranged between the second gate electrode and the active layer.

[0015] In one embodiment of the present disclosure, the organic light-emitting transistor further comprises an encapsulation layer, the encapsulation layer is arranged on the side of the first electrode and the second electrode away from the substrate, part of the encapsulation layer is located on the second micro-nano grating structure, part of the encapsulation layer is located on the fourth micro-nano grating structure, and part of the encapsulation layer is located on the planar region of the electron transport layer.

[0016] In one embodiment of this disclosure, the organic light-emitting transistor further includes a first gate, which is disposed on the side of the second electrode and the first electrode away from the substrate. A first insulating layer is disposed between the first gate and the second electrode and the first electrode. A portion of the first insulating layer is located on a second micro-nano grating structure, a portion is located on a fourth micro-nano grating structure, and a portion is located on a planar region of the electron transport layer.

[0017] In one embodiment of this disclosure, the organic light-emitting transistor further includes an encapsulation layer disposed on the side of the first gate away from the substrate and in contact with the first gate.

[0018] In one embodiment of this disclosure, a first micro-nano grating structure is disposed on the entire surface of the electron transport layer, a first electrode is disposed on the first micro-nano grating structure, and the organic light-emitting transistor further includes a second electrode and a first gate. The second electrode is disposed between the substrate and the active layer; the first gate is disposed between the second electrode and the substrate, and a first insulating layer is disposed between the first gate and the second electrode.

[0019] In one embodiment of this disclosure, the organic light-emitting transistor further includes a second gate, which is disposed between the first insulating layer and the second electrode, and a second insulating layer is disposed between the second gate and the second electrode.

[0020] In one embodiment of this disclosure, the organic light-emitting transistor further includes an encapsulation layer disposed on the side of the first electrode away from the substrate and located on the first micro / nano grating structure.

[0021] According to another aspect of this disclosure, a method for fabricating an organic light-emitting transistor is provided, comprising:

[0022] Provide substrates;

[0023] An active layer is formed on one side of the substrate.

[0024] A hole transport layer is formed on the side of the active layer away from the substrate.

[0025] A light-emitting layer is formed on the side of the hole transport layer away from the substrate.

[0026] An electron transport layer is formed on the side of the light-emitting layer away from the substrate.

[0027] At least a portion of the first micro / nano grating structure is formed on the side of the electron transport layer away from the substrate.

[0028] A first electrode is formed in the region of the electron transport layer where a first micro-nano grating structure is provided. At least a portion of a second micro-nano grating structure is formed on the side of the first electrode away from the substrate. The orthographic projection of the second micro-nano grating structure onto the substrate is located within the orthographic projection of the first micro-nano grating structure onto the substrate.

[0029] According to yet another aspect of this disclosure, a display panel is provided, including the organic light-emitting transistor described in one aspect of this disclosure.

[0030] According to another aspect of this disclosure, a display device is provided, including the display panel described in another aspect of this disclosure.

[0031] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0032] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0033] Figure 1 This is a schematic diagram of the structure of an organic light-emitting transistor according to an embodiment of this disclosure.

[0034] Figure 2 This is a schematic diagram of the structure of the first electrode involved in an embodiment of this disclosure.

[0035] Figure 3 This is a schematic diagram of another structure of the first electrode involved in an embodiment of this disclosure.

[0036] Figure 4 This is a schematic diagram of another structure of the organic light-emitting transistor involved in the embodiments of this disclosure.

[0037] Figure 5 This is a schematic diagram of the structure of the embossing template involved in the embodiments of this disclosure.

[0038] Figure 6 This is another schematic diagram of the organic light-emitting transistor involved in the embodiments of this disclosure.

[0039] Figure 7 This is another schematic diagram of the organic light-emitting transistor involved in the embodiments of this disclosure.

[0040] Figure 8 This is another schematic diagram of the organic light-emitting transistor involved in the embodiments of this disclosure.

[0041] Figure 9 This is another schematic diagram of the organic light-emitting transistor involved in the embodiments of this disclosure.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Substrate; 2. First gate electrode; 3. First insulating layer; 4. Active layer; 5. Hole transport layer; 6. Light-emitting layer; 7. Electron transport layer; 71. First micro / nano grating structure; 711. First strip groove; 72. Third micro / nano grating structure; 721. Third strip groove; 8. First electrode; 81. Fifth micro / nano grating structure; 811. Fifth convex strip; 82. Second micro / nano grating structure; 821. Second strip groove; 9. 91. Second electrode; 92. Seventh micro / nano grating structure; 93. Seventh convex strip; 94. Fourth micro / nano grating structure; 95. Fourth strip groove; 10. Encapsulation layer; 101. Sixth micro / nano grating structure; 101. Sixth convex strip; 102. Eighth micro / nano grating structure; 102. Eighth convex strip; 11. Second gate; 12. Second insulating layer; 13. Imprint template; 14. Imprint pattern; 15. Strip imprint groove. Detailed Implementation

[0044] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0045] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0046] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0047] The external quantum efficiency (EQE) of conventional organic light-emitting transistors (OLETs) remains severely limited by their low light extraction efficiency, suffering from internal energy losses due to waveguide modes, substrate modes, and surface plasmon modes. This results in only about 20% of photons being extracted from the OLET, significantly restricting its commercial application prospects. In related technologies, waveguide and substrate modes typically employ alternative materials to indium tin oxide (ITO) to mitigate internal energy losses in OLETs. Therefore, the internal energy loss caused by OLET surface plasmon modes is a pressing issue that needs to be addressed.

[0048] At room temperature and pressure, a large number of free electrons exist in a ionized state both inside and on the surface of metals, forming free electron clusters, which are called plasmas. Surface plasmas are a special electromagnetic mode at the interface between metals and other materials. The wave vector of a surface plasma mode is generally larger than that of light at the same frequency, so electrons in this mode can usually only propagate on the metal surface. Furthermore, due to the thermal loss effect of metals at room temperature, surface plasma mode electrons can only propagate a limited distance; the continuous fluctuation of electrons at the metal interface is called surface plasma oscillation. For continuous metal interfaces, when the light wave vector is smaller than the surface plasma wave vector, the surface plasma mode is a non-radiative mode. In OLET, since metals are inevitably used as electrodes, there will inevitably be interfaces between metals and other media, leading to surface plasma mode losses at the interface.

[0049] Based on this, an exemplary embodiment of this disclosure provides an organic light-emitting transistor. For example... Figures 1 to 9 As shown, the organic light-emitting transistor includes a substrate 1, an active layer 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, and a first electrode 8. The active layer 4 is disposed on one side of the substrate 1; the hole transport layer 5 is disposed on the side of the active layer 4 away from the substrate 1; the light-emitting layer 6 is disposed on the side of the hole transport layer 5 away from the substrate 1; the electron transport layer 7 is disposed on the side of the light-emitting layer 6 away from the substrate 1, and at least a portion of a first micro-nano grating structure 71 is provided on the side of the electron transport layer 7 away from the substrate 1; the first electrode 8 is disposed on the side of the electron transport layer 7 away from the substrate 1, and at least a portion of a second micro-nano grating structure 82 is provided on the side of the first electrode 8 away from the substrate 1. The orthographic projection of the second micro-nano grating structure 82 onto the substrate 1 is located within the orthographic projection of the first micro-nano grating structure 71 onto the substrate 1.

[0050] In OLET, since the first electrode 8 is inevitably made of metal, surface plasmon mode loss will inevitably exist at the interface of the first electrode 8. By employing a grating coupling method, at least a portion of the first micro-nano grating structure 71 is provided on the side of the electron transport layer 7 away from the substrate 1, so that at least a portion of the second micro-nano grating structure 82 is formed on the side of the first electrode 8 away from the substrate 1. The first micro-nano grating structure 71 and the second micro-nano grating structure 82 can effectively excite the interface between the first electrode and other film layers to couple light out in surface plasmon mode, which can effectively reduce the energy loss in surface plasmon mode inside the OLET and improve the luminous efficiency of the OLET.

[0051] Taking a bottom-gate organic light-emitting transistor as an example, the first micro-nano grating structure 71 formed at the interface between the electron transport layer 7 and the first electrode 8 is used to complete the wave vector matching, thereby realizing the light-emitting coupling of surface plasma.

[0052] The specific principle is as follows: the grating period is Λ, the incident angle of light is α, and the momentum conservation in the waveguide plane can be calculated by the following formula:

[0053] k || =k0sinα=K wg ±mK G ;

[0054] Where, k || Let k be the wave vector in the plane, and k0 represent the wave vector in free space. wg k is the wave vector within the waveguide effect surface. G denoted as the wave vector within the first micro-nano grating structure 71, where m is an integer.

[0055]

[0056] Where, n eff λ is the effective refractive index; λ is the emission wavelength.

[0057]

[0058] Where, ε i d is the dielectric constant. i The thickness is the film thickness.

[0059] The k0 in air mode is 12 μm -1 The surface plasmon mode k || It is relatively large, at 26μm. -1 The surface of the first electrode 8 is provided with a first micro / nano grating structure 71, and the wave vector k within the first micro / nano grating structure 71 is... G This can reduce the wave vector K within the waveguide effect surface. wh This can effectively reduce the wave vector k in the plane.|| When the wave vector k in the plane || When the wave vector k0 in free space is less than that in free space, the excited plasma mode is converted into an emissive mode, effectively extracting the emitted light. This effectively reduces energy loss caused by the OLET surface plasma mode and improves the OLET's luminescence efficiency.

[0060] It should be noted that the top-gate organic light-emitting transistor mainly utilizes the second micro-nano grating structure 82 formed at the interface between the first electrode 8 and the first insulating layer 3 to complete the wave vector matching, thereby realizing the light-emitting coupling of surface plasmonic particles.

[0061] The following is about Figures 1 to 9 The structure and fabrication process of the organic light-emitting transistors involved are described in detail.

[0062] like Figure 1 As shown, the organic light-emitting transistor is a bottom-gate organic light-emitting transistor, including a substrate 1. A first gate 2 is provided on one side of the substrate 1. A first insulating layer 3 is provided on the side of the first gate 2 away from the substrate 1. An active layer 4 is provided on the side of the first insulating layer 3 away from the substrate 1. A hole transport layer 5 is provided on the side of the active layer 4 away from the substrate 1. A light-emitting layer 6 is provided on the side of the hole transport layer 5 away from the substrate 1. An electron transport layer 7 is provided on the side of the light-emitting layer 6 away from the substrate 1.

[0063] A portion of the electron transport layer 7 away from the substrate 1 is a planar region located in the middle of the electron transport layer 7. A first region and a second region are symmetrically arranged on either side of this planar region. The first region has a first micro / nano grating structure 71 with a first electrode 8. A second micro / nano grating structure 82 is located on the side of the first electrode 8 away from the substrate 1, and the orthographic projection of the second micro / nano grating structure 82 onto the substrate 1 lies within the orthographic projection of the first micro / nano grating structure 71 onto the substrate 1. The second region has a third micro / nano grating structure 72 with a second electrode 9. A fourth micro / nano grating structure 92 is located on the side of the second electrode 9 away from the substrate 1, and the orthographic projection of the fourth micro / nano grating structure 92 onto the substrate 1 lies within the orthographic projection of the third micro / nano grating structure 72 onto the substrate 1.

[0064] An encapsulation layer 10 is provided on the side of the first electrode 8 and the second electrode 9 away from the substrate 1. Part of the encapsulation layer 10 is located on the second micro-nano grating structure 82, part is located on the fourth micro-nano grating structure 92, and part is located on the planar region of the electron transport layer 7.

[0065] The first micro / nano grating structure 71 includes a plurality of parallel first strip-shaped grooves 711. Along a direction perpendicular to the extending direction of the first strip-shaped grooves 711, the cross-sectional shape of the first strip-shaped grooves 711 is rectangular, with a width of 200-600 nm, a depth of 10-50 nm, and a spacing of 5-50 nm between adjacent first strip-shaped grooves 711. A fifth micro / nano grating structure 81 is formed on the side of the first electrode 8 near the substrate 1. The fifth micro / nano grating structure 81 includes a plurality of parallel fifth protrusions 811, the cross-sectional shape and size of which are adapted to the cross-sectional shape and size of the first strip-shaped grooves 711. That is, the width of the fifth protrusion 811 is 200-600 nm, the height is 10-50 nm, and the spacing between adjacent fifth protrusions 811 is 5-50 nm. The fifth protrusions 811 fill the first strip-shaped grooves 711.

[0066] like Figure 2 As shown, the second micro / nano grating structure 82 includes a plurality of parallel second strip-shaped grooves 821. Along a direction perpendicular to the extending direction of the second strip-shaped grooves 821, the cross-sectional shape of the second strip-shaped grooves 821 is rectangular, with a width of 200-600 nm, a depth of 10-50 nm, and a spacing of 5-50 nm between adjacent second strip-shaped grooves 821. A sixth micro / nano grating structure 101 is formed on the side of the encapsulation layer near the substrate 1. The sixth micro / nano grating structure 101 includes a plurality of parallel sixth protrusions 1011, the cross-sectional shape and dimensions of which are adapted to the cross-sectional shape and dimensions of the second strip-shaped grooves 821. That is, the width of the sixth protrusion 1011 is 200-600 nm, the height is 10-50 nm, and the spacing between adjacent sixth protrusions 1011 is 5-50 nm. The sixth protrusions 1011 fill the second strip-shaped grooves 821.

[0067] The third micro / nano grating structure 72 includes multiple parallelly distributed third strip-shaped grooves 721. Along a direction perpendicular to the extension direction of the third strip-shaped grooves 721, the cross-sectional shape of the third strip-shaped grooves 721 is rectangular, with a width of 200-600 nm, a depth of 10-50 nm, and a spacing of 5-50 nm between adjacent third strip-shaped grooves 721. A seventh micro / nano grating structure 91 is formed on the side of the first electrode 8 near the substrate 1. The seventh micro / nano grating structure 91 includes multiple parallelly distributed seventh protrusions 911, the cross-sectional shape and dimensions of which are adapted to the cross-sectional shape and dimensions of the third strip-shaped grooves 721. That is, the width of the seventh protrusion 911 is 200-600 nm, the height is 10-50 nm, and the spacing between adjacent seventh protrusions 911 is 5-50 nm. The seventh protrusions 911 fill the third strip-shaped grooves 721.

[0068] The fourth micro / nano grating structure 92 includes multiple parallelly distributed fourth strip-shaped grooves 921. Along a direction perpendicular to the extension direction of the fourth strip-shaped grooves 921, the cross-sectional shape of each fourth strip-shaped groove 921 is rectangular, with a width of 200-600 nm, a depth of 10-50 nm, and a spacing of 5-50 nm between adjacent fourth strip-shaped grooves 921. An eighth micro / nano grating structure 102 is formed on the side of the encapsulation layer closest to the substrate 1. The eighth micro / nano grating structure 102 includes multiple parallelly distributed eighth protrusions 1021, the cross-sectional shape and dimensions of which are adapted to the cross-sectional shape and dimensions of the fourth strip-shaped grooves 921. That is, the width of each eighth protrusion 1021 is 200-600 nm, the height is 10-50 nm, and the spacing between adjacent eighth protrusions 1021 is 5-50 nm. The eighth protrusions 1021 fill the fourth strip-shaped grooves 921.

[0069] like Figure 3 As shown, along the direction perpendicular to the extending direction of the second strip groove 821, the cross-sectional shape of the fifth protrusion 811 and the second strip groove 821 can also be arc-shaped. For example... Figure 4 As shown, the cross-sectional shape of the first strip groove 711 is an arc shape that matches the cross-sectional shape of the fifth protrusion 811, and the cross-sectional shape of the sixth protrusion 1011 is an arc shape that matches the cross-sectional shape of the second strip groove 821. It can be understood that the third strip groove 721 has the same shape as the first strip groove 711, the seventh protrusion 911 has the same shape as the fifth protrusion 811, the fourth strip groove 921 has the same shape as the second strip groove 821, and the eighth protrusion 1021 has the same shape as the sixth protrusion 1011; these details will not be elaborated further here.

[0070] In other feasible embodiments, the first micro-nano grating structure 71, the second micro-nano grating structure 82, the third micro-nano grating structure 72 and the fourth micro-nano grating structure 92 may include a plurality of dot-shaped recesses arranged in an array, and the fifth micro-nano grating structure 81, the sixth micro-nano grating structure 101, the seventh micro-nano grating structure 91 and the eighth micro-nano grating structure 102 have dot-shaped protrusions that correspond one-to-one with each dot-shaped recess, and the dot-shaped protrusions fill the dot-shaped recesses.

[0071] It should be noted that the first electrode 8 mentioned above can be the drain, and the second electrode 9 can be the source. The OLET can control the amount of light emitted by the light-emitting layer 6 (EL) of the organic light-emitting transistor using the voltage of the first gate 2. The second electrode 9 mainly provides holes, and the first electrode 8 mainly provides electrons. The electric field of the first gate 2 can be used to control the recombination ratio between holes injected into the light-emitting layer 6 through the second electrode 9 and electrons injected into the light-emitting layer 6 through the first electrode 8, thereby changing the amount of light emitted.

[0072] The substrate 1 can be made of glass, silicon wafer, or synthetic resins such as polyethylene terephthalate (PET), polyethersulfone (PES), or polycarbonate (PC). Glass is commonly used as the substrate 1 for double-sided organic light-emitting transistors (OLEDs); silicon wafers are more commonly used for single-sided OLEDs. The first gate 2 is typically made of indium tin oxide (ITO), but other conductive oxides can also be used. The first insulating layer 3 can be made of inorganic or organic materials, and its thickness is typically between 20 nm and 2000 nm.

[0073] The active layer 4 can be polycrystalline silicon or metal oxide, and its thickness is generally between 20 nm and 2000 nm. The hole transport layer 5 (HTL), light-emitting layer 6 (EML), and electron transport layer 7 (ETL) are all materials used in conventional OLED devices. The thickness of the electron transport layer 7 is 15–50 nm, the thickness of the light-emitting layer 6 is 30–60 nm, and the thickness of the hole transport layer 5 is 10–30 nm. The first electrode 8 and the second electrode 9 can be made of the same material, such as LiF / Al, or Au. The thickness of both the first electrode 8 and the second electrode 9 can be set to 30–90 nm. Of course, the first electrode 8 and the second electrode 9 can also adopt different structures. For example, the first electrode 8 can be graphene, and the second electrode 9 can be Al; alternatively, the first electrode 8 can be made of MoO3 / Au, and the second electrode 9 can be made of LiF / Al.

[0074] The fabrication process of organic light-emitting transistors is as follows:

[0075] The first gate 2 is disposed on the substrate 1, and the first insulating layer 3 is generally disposed on the first gate 2 by plasma-enhanced chemical vapor deposition (PECVD). The electron transport layer 7, the light-emitting layer 6, and the hole transport layer 5 can all be prepared by vacuum evaporation, spin coating, or printing processes, which will not be described in detail here.

[0076] After the electron transport layer 7 is deposited, the deposited substrate 1 is removed, and the prepared polydimethylsiloxane (PDMS) imprint template is attached to the electron transport layer 7. Then, it is transferred to a nanoimprinter for imprinting. Subsequently, the imprint template is peeled off. At this time, the micro-nano pattern of the imprint template has been completely transferred to the surface of the electron transport layer 7.

[0077] The substrate 1 is then transferred to a vacuum evaporation apparatus to deposit the first electrode 8 and the second electrode 9 on the surface of the electron transport layer 7, which has already formed a micro-nano pattern, in one step. At this point, the micro-nano pattern on the surface of the electron transport layer 7 can be completely transferred to the first electrode 8 and the second electrode 9. Finally, an encapsulation layer 10 is used for encapsulation, which can be a stacked inorganic thin film encapsulation or a stacked inorganic and organic thin film encapsulation.

[0078] like Figure 5 As shown, the surface of the imprint template 13 is provided with periodic micro-nano patterns. The micro-nano patterns include several parallel imprint patterns 131. The imprint patterns 131 include parallel strip imprint grooves 1311. The width of the strip imprint grooves 1311 is 200-600nm, the depth is 10-50nm, and the interval between two adjacent strip imprint grooves 1311 is 5-50nm.

[0079] An imprint template 13 with periodic micro / nano patterns can be prepared through the following process: Electron beam etching is performed on a silicon template to create micro / nano patterns of different periods, ranging from 200-600 nm in diameter and 10-50 nm in depth, spaced 5-50 nm apart. After cleaning the silicon template to remove any residual photoresist protective layer, a PDMS solution mixed with a curing agent is drop-coated onto the template. Once the solution has spread evenly on the silicon template, it is cured in an oven at 95°C for 10 hours. After curing, the PDMS layer is peeled off. At this point, the imprint template 13 has successfully replicated the periodic micro / nano patterns on the silicon template and is ready for use in subsequent imprinting processes.

[0080] like Figure 6 As shown, the organic light-emitting transistor and Figure 1 The difference in the illustrated organic light-emitting transistor (OLED) is that it is a top-gate OLED. The active layer 4 is disposed on one side of the substrate 1, the first insulating layer 3 is disposed on the side of the first electrode 8 and the second electrode 9 away from the substrate 1, the first gate 2 is disposed on the side of the second insulating layer 3 away from the substrate 1, and the encapsulation layer 10 is disposed on the side of the first gate 2 away from the substrate 1. The sixth micro / nano grating structure 101 and the eighth micro / nano grating structure 102 are spaced apart on the side of the first insulating layer 3 near the first electrode 8.

[0081] The organic light-emitting transistor comprises a substrate 1, an active layer 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, a first electrode 8, a second electrode 9, a first insulating layer 3, a first gate 2, and an encapsulation layer 10. The materials and fabrication processes used are similar to those employed in this organic light-emitting transistor. Figure 1 The organic light-emitting transistors shown are basically the same, so they will not be described in detail here.

[0082] like Figure 7 As shown, the organic light-emitting transistor and Figure 1 The difference in the illustrated organic light-emitting transistor (OLED) lies in that it is a double-gate OLED. A second gate 11 is provided on the side of the first insulating layer 3 away from the substrate 1, and a second insulating layer 12 is provided on the side of the second gate 11 away from the substrate 1. The active layer 4 is located on the side of the second insulating layer 12 away from the substrate 1. It should also be noted that the orthographic projection of the second gate 11 onto the substrate 1 is smaller than the orthographic projection of the first gate 2 onto the substrate 1. Both the first gate 2 and the second gate 11 can control the amount of charge transferred to the radiative recombination region, achieving a balance point where the charge density at the boundary of the light-emitting layer is equal, thus obtaining optimal operation under high current.

[0083] The materials and fabrication process used for the second gate 11 are basically the same as those used for the first gate 2, and the materials and fabrication process used for the second insulating layer 12 are basically the same as those used for the first insulating layer 3. The substrate 1, active layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, first electrode 8, second electrode 9, first insulating layer 3, first gate 2, and encapsulation layer 10 of this organic light-emitting transistor also use the same materials and fabrication processes as those used for the first gate 2. Figure 1 The organic light-emitting transistors shown are basically the same, so they will not be described in detail here.

[0084] like Figure 8 As shown, the organic light-emitting transistor and Figure 1 The difference in the illustrated organic light-emitting transistor (OLED) lies in that the first region is the entire surface of the electron transport layer 7 away from the substrate 1, and the entire surface of the electron transport layer 7 is provided with a first micro / nano grating structure 71. The entire surface of the first electrode 8 near the substrate 1 is provided with a fifth micro / nano grating structure 81, and the entire surface of the first electrode 8 away from the substrate 1 is provided with a second micro / nano grating structure 82. The entire surface of the encapsulation layer 10 near the substrate 1 is provided with a sixth micro / nano grating structure 101. The second electrode 9 is disposed between the first insulating layer 3 and the active layer 4, and the side of the second electrode 9 away from the substrate 1 is planar. The materials and fabrication processes used in the substrate 1, active layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, first electrode 8, second electrode 9, first insulating layer 3, first gate 2, and encapsulation layer 10 of this OLED are similar to those used in other OLEDs. Figure 1 The organic light-emitting transistors shown are basically the same, so they will not be described in detail here.

[0085] like Figure 9 As shown, the organic light-emitting transistor and Figure 8 The difference in the illustrated organic light-emitting transistor is that a second gate 11 is provided on the side of the first insulating layer 3 away from the substrate 1, and a second insulating layer 12 is provided on the side of the second gate 11 away from the substrate 1. The second electrode 9 is located on the side of the second insulating layer 12 away from the substrate 1. The material and fabrication process of the second gate 11 can be the same as those of the first gate 2, and the material and fabrication process of the second insulating layer 12 can be the same as those of the first insulating layer 3.

[0086] This disclosure provides a display device including the display panel described above. The structure of the display panel has been described in detail above and will not be repeated here. The beneficial effects of this display device can also be referred to the beneficial effects of the display panel.

[0087] Display devices can be used in traditional electronic devices, such as mobile phones, computers, televisions, and video recorders, or in emerging wearable devices, such as virtual reality devices and augmented reality devices, which will not be listed here.

[0088] It should be noted that, in addition to the display panel, the display device also includes other necessary components and parts. For example, the display device may include the casing, power cord, etc. Those skilled in the art can make corresponding additions according to the specific usage requirements of the display device, which will not be elaborated here.

[0089] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. An organic light-emitting transistor, characterized in that, include: Substrate; An active layer is disposed on one side of the substrate. A hole transport layer is disposed on the side of the active layer away from the substrate. A light-emitting layer is disposed on the side of the hole transport layer away from the substrate. An electron transport layer is disposed on the side of the light-emitting layer away from the substrate, and at least a portion of the first micro-nano grating structure is provided on the side of the electron transport layer away from the substrate. A first electrode is disposed on the side of the electron transport layer away from the substrate. At least a portion of a second micro / nano grating structure is provided on the side of the first electrode away from the substrate. The orthographic projection of the second micro / nano grating structure on the substrate is located within the orthographic projection of the first micro / nano grating structure on the substrate. The electron transport layer has a first region and a second region spaced apart on the side away from the substrate. A portion of the electron transport layer on the side away from the substrate is a planar region. The first region and the second region are symmetrically arranged on both sides of the planar region. The first micro / nano grating structure is located in the first region, and the first electrode is disposed on the first micro / nano grating structure. The second region has a third micro / nano grating structure. The organic light-emitting transistor further includes: A second electrode is disposed on the third micro-nano grating structure. A fourth micro-nano grating structure is disposed on the side of the second electrode away from the substrate. The orthographic projection of the fourth micro-nano grating structure on the substrate is located within the orthographic projection of the third micro-nano grating structure on the substrate.

2. The organic light-emitting transistor according to claim 1, characterized in that, The electron transport layer is located on the side away from the substrate, and the area between the first electrode and the second electrode is a planar region.

3. The organic light-emitting transistor according to claim 1, characterized in that, The first micro-nano grating structure, the second micro-nano grating structure, the third micro-nano grating structure, and the fourth micro-nano grating structure are all periodic micro-nano grating structures. The periodic micro-nano grating structure includes a plurality of parallel strip grooves, each strip groove having an equal width and an equal spacing between adjacent grooves.

4. The organic light-emitting transistor according to claim 3, characterized in that, Along a direction perpendicular to the extension direction of the strip groove, the cross-sectional shape of the strip groove is rectangular or arc-shaped.

5. The organic light-emitting transistor according to claim 4, characterized in that, When the cross-sectional shape of the strip groove is rectangular, the width of the strip groove is 200-600 nm, the depth is 10-50 nm, and the spacing between two adjacent strip grooves is 5-50 nm.

6. The organic light-emitting transistor according to claim 1, characterized in that, The first micro-nano grating structure, the second micro-nano grating structure, the third micro-nano grating structure, and the fourth micro-nano grating structure are all periodic micro-nano grating structures, and the periodic micro-nano grating structure includes multiple dot-shaped recesses arranged in an array.

7. The organic light-emitting transistor according to claim 2, characterized in that, The organic light-emitting transistor also includes: A first gate is disposed between the substrate and the active layer, and a first insulating layer is disposed between the first gate and the active layer.

8. The organic light-emitting transistor according to claim 7, characterized in that, The organic light-emitting transistor also includes: A second gate is disposed between the first insulating layer and the active layer, and a second insulating layer is disposed between the second gate and the active layer.

9. The organic light-emitting transistor according to claim 7 or 8, characterized in that, The organic light-emitting transistor also includes: An encapsulation layer is disposed on the side of the first electrode and the second electrode away from the substrate. A portion of the encapsulation layer is located on the second micro-nano grating structure, a portion is located on the fourth micro-nano grating structure, and a portion is located on the planar region of the electron transport layer.

10. The organic light-emitting transistor according to claim 2, characterized in that, The organic light-emitting transistor also includes: A first gate is disposed on the side of the second electrode and the first electrode away from the substrate. A first insulating layer is disposed between the first gate and the second electrode and the first electrode. A portion of the first insulating layer is located on the second micro-nano grating structure, a portion is located on the fourth micro-nano grating structure, and a portion is located on the planar region of the electron transport layer.

11. The organic light-emitting transistor according to claim 10, characterized in that, The organic light-emitting transistor also includes: An encapsulation layer is disposed on the side of the first gate away from the substrate and is in contact with the first gate.

12. A method for fabricating an organic light-emitting transistor, characterized in that, include: Provide substrates; An active layer is formed on one side of the substrate. A hole transport layer is formed on the side of the active layer away from the substrate. A light-emitting layer is formed on the side of the hole transport layer away from the substrate. An electron transport layer is formed on the side of the light-emitting layer away from the substrate. At least a portion of the first micro / nano grating structure is formed on the side of the electron transport layer away from the substrate. A first electrode is formed in the region of the electron transport layer where a first micro-nano grating structure is provided. At least a portion of a second micro-nano grating structure is formed on the side of the first electrode away from the substrate. The orthographic projection of the second micro-nano grating structure onto the substrate is located within the orthographic projection of the first micro-nano grating structure onto the substrate. The electron transport layer has a first region and a second region spaced apart on the side away from the substrate. A portion of the electron transport layer on the side away from the substrate is a planar region. The first region and the second region are symmetrically arranged on both sides of the planar region. The first micro / nano grating structure is located in the first region, and the first electrode is disposed on the first micro / nano grating structure. The second region has a third micro / nano grating structure. The organic light-emitting transistor further includes: A second electrode is disposed on the third micro-nano grating structure. A fourth micro-nano grating structure is disposed on the side of the second electrode away from the substrate. The orthographic projection of the fourth micro-nano grating structure on the substrate is located within the orthographic projection of the third micro-nano grating structure on the substrate.

13. A display panel, characterized in that, The organic light-emitting transistor includes any one of claims 1 to 11.

14. A display device, characterized in that, Includes the display panel as described in claim 13.

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