Composite device with sensing display function, display screen and electronic equipment

Abstract

The invention discloses a composite device with a sensing function, a display screen and electronic equipment, and the composite device comprises a first functional layer which is located at one side of an anode; the light-emitting layer is located on one side of the first functional layer away from the anode; the second functional layer is located on one side of the light-emitting layer away from the anode; the cathode is positioned on one side, away from the anode, of the second functional layer; wherein the first functional layer is a P-type organic semiconductor layer, and the second functional layer is an N-type organic semiconductor layer; the first functional layer and the second functional layer are used for forming a PN junction structure; under forward voltage, the PN junction structure is used as a carrier transmission function layer; under a reverse voltage, the PN junction structure is used as an optical detection function layer. According to the technical scheme provided by the invention, the signal interference is prevented while the effective photosensitive area is enlarged, and the size and the process complexity of the display screen are reduced.

Description

Technical Field

[0001] The present invention relates to the field of organic optoelectronics technology, and in particular to a composite device, display screen and electronic device with sensing and display functions. Background Technology

[0002] Traditional display devices, such as organic light-emitting diode (OLED) displays, typically only have image display capabilities. To enable applications such as ambient light detection, touch sensing, or optical interaction, a separate photodetector, such as a silicon photodiode (PD), must be integrated outside the display area. This discrete design significantly increases the size and thickness of the device, raises system costs, and can potentially cause signal response delays, impacting the user experience.

[0003] In related technologies, OLEDs are integrated with organic photodetectors (OPDs) within the display area to mitigate the problems caused by integrating separate PDs outside the display area. However, these technologies often employ a physically separate, side-by-side layout when functionally integrating OLEDs and OPDs. For example, each pixel area typically includes four units: a red sub-pixel (R), a green sub-pixel (G), a blue sub-pixel, and the OPD. This structure limits the effective photosensitive area within the confined device space, resulting in low layout efficiency. Furthermore, optical crosstalk and electrical coupling interference easily occur between the display and detection units, leading to a decrease in the detector's signal-to-noise ratio and unstable performance. In addition, the discrete integration of multiple components increases process complexity. Therefore, a novel device architecture capable of integrating display and detection is urgently needed. Summary of the Invention

[0004] This invention provides a composite device, display screen, and electronic device with sensing and display functions, which improves the effective light-sensitive area while preventing signal interference and reducing the size and manufacturing complexity of the display screen.

[0005] According to one aspect of the present invention, a composite device with sensing and display functions is provided, comprising:

[0006] The first functional layer is located on one side of the anode;

[0007] The light-emitting layer is located on the side of the first functional layer away from the anode;

[0008] The second functional layer is located on the side of the light-emitting layer away from the anode;

[0009] The cathode is located on the side of the second functional layer away from the anode;

[0010] Wherein, the first functional layer is a P-type organic semiconductor layer, and the second functional layer is an N-type organic semiconductor layer; the first functional layer and the second functional layer are used to form a PN junction structure; under forward voltage, the PN junction structure is used as a carrier transport functional layer; under reverse voltage, the PN junction structure is used as a photodetector functional layer.

[0011] Optionally, the first functional layer includes at least one hole transport material; the hole transport material is an electron-rich organic semiconductor material, and the highest occupied molecular orbital energy level of the hole transport material is below -5.0 eV;

[0012] Under the forward voltage, the first functional layer is used to transfer the holes injected by the anode to the light-emitting layer; under the reverse voltage, the first functional layer is used to absorb light to generate excitons, and based on the built-in electric field between itself and the second functional layer, to split the excitons into electrons and holes.

[0013] Preferably, the material of the first functional layer includes one or more of conjugated olefins, aromatic rings, pentacene, poly(3-hexylthiophene), and copper phthalocyanine.

[0014] Optionally, the second functional layer includes at least one electron transport material, which is an electron-deficient organic semiconductor material; the lowest unoccupied molecular orbital energy level of the electron transport material is between -4.0 eV and -3.5 eV;

[0015] Under the forward voltage, the second functional layer is used to transfer electrons injected by the cathode to the light-emitting layer; under the reverse voltage, the second functional layer is used to absorb light to generate excitons and, based on the built-in electric field between itself and the first functional layer, split the excitons into electrons and holes.

[0016] Preferably, the material of the second functional layer includes fullerene C 60 Fullerene C 70 One or more of perylene tetracarboxylic dianhydride (PTCDA) and N,N'-dioctyl-3,4,9,10-perylene diimide (PDI).

[0017] Optionally, the light-emitting layer includes: a light-emitting material layer, at least one of a hole transport layer and an electron blocking layer located between the light-emitting material layer and the first functional layer, and at least one of an electron transport layer and a hole blocking layer located between the light-emitting material layer and the second functional layer;

[0018] And / or, the composite device further includes a hole injection layer located between the anode and the first functional layer;

[0019] And / or, the composite device further includes an electron injection layer located between the cathode and the second functional layer.

[0020] Optionally, the thickness of the light-emitting layer is less than or equal to 50 nm.

[0021] According to another aspect of the present invention, a display screen is provided, comprising:

[0022] Multiple sub-pixels, wherein at least some of the sub-pixels employ a composite device with sensing and display functions as described in any embodiment of the present invention;

[0023] The driving circuit layer includes multiple driving circuit units, each driving circuit unit being electrically connected to one of the sub-pixels; wherein the driving circuit unit electrically connected to the composite device is used to apply a positive voltage or a reverse voltage to the composite device.

[0024] The control module is used to switch the voltage direction of the drive circuit unit to switch the display mode and the detection mode of the composite device.

[0025] Optionally, the display screen further includes:

[0026] A pixel definition layer is located between two adjacent sub-pixels; the thickness of the pixel definition layer is greater than or equal to 2µm.

[0027] Optionally, in the display operating mode, the positive voltage applied by the driving circuit unit to the composite device is in the range of 3V~15V; in the composite device, the first functional layer is used to inject holes into the light-emitting layer, and the second functional layer is used to inject electrons into the light-emitting layer, so that the holes and the electrons recombine and emit light in the light-emitting layer;

[0028] In the detection mode, the reverse voltage applied by the driving circuit unit to the composite device ranges from 0.1V to 10V; in the composite device, the first functional layer and the second functional layer are used to detect optical signals and convert the optical signals into electrical signals.

[0029] Optionally, the control module is configured to control the composite device to switch between display working mode and detection working mode, and adjust its working frequency accordingly;

[0030] The display working mode corresponds to the first frequency range;

[0031] The detection mode corresponds to the second frequency range;

[0032] Wherein, the lower limit of the first frequency range is higher than or equal to the upper limit of the second frequency range;

[0033] Preferably, the first frequency range is 60Hz to 240Hz; the second frequency range is 1Hz to 60Hz.

[0034] According to another aspect of the present invention, an electronic device is provided, including a display screen as described in any embodiment of the present invention;

[0035] The display screen is configured to both emit display light to achieve the display function and receive external light to achieve the light detection function.

[0036] The technical solution provided by this invention embeds the P-type organic semiconductor layer and N-type organic semiconductor layer of the OPD into the OLED as the first functional layer and the second functional layer, respectively. The first and second functional layers can promote carrier recombination under forward bias (which is beneficial for light emission) and form a depletion region under reverse bias (which is beneficial for photodetection). This allows the same structure to realize display and detection functions under different biases. Compared with the side-by-side layout of OLED and OPD, the display and detection functions are integrated into a composite device, which significantly improves the integration of the display screen, increases the effective photosensitive area in the display screen, prevents signal interference between the detection signal and the light emission driving signal, and reduces the size and process complexity of the display screen.

[0037] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a composite device with sensing and display functions provided in an embodiment of the present invention;

[0040] Figure 2 yes Figure 1 A schematic diagram of the structure shown in the diagram under forward voltage;

[0041] Figure 3 yes Figure 1 The diagram shows the operation of the structure under reverse voltage.

[0042] Figure 4 This is a schematic diagram of another composite device with sensing and display functions provided in an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of another composite device with sensing and display functions provided in an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of another composite device with sensing and display functions provided in an embodiment of the present invention;

[0045] Figure 7 yes Figure 6 A schematic diagram of the energy levels of the materials in each membrane layer of the structure shown;

[0046] Figure 8 This is a schematic diagram of the voltage-current density-brightness characteristic curves of a composite device with sensing and display functions provided in an embodiment of the present invention under forward voltage;

[0047] Figure 9 This is a schematic diagram of the current efficiency-brightness characteristic curve of a composite device with sensing and display functions provided in an embodiment of the present invention under forward voltage;

[0048] Figure 10 This is a comparison graph of the current density versus voltage curves of a composite device under illumination and without illumination, provided by an embodiment of the present invention.

[0049] Figure 11 This is a partial structural diagram of a display screen provided in an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] This invention provides a composite device with sensing and display functions. Figure 1 This is a schematic diagram of the structure of a composite device with sensing and display functions provided in an embodiment of the present invention. (Refer to...) Figure 1 ,include:

[0053] Anode 11;

[0054] The first functional layer 21 is located on one side of the anode 11;

[0055] The light-emitting layer 30 is located on the side of the first functional layer 21 away from the anode 11;

[0056] The second functional layer 22 is located on the side of the light-emitting layer 30 away from the anode 11;

[0057] The cathode 12 is located on the side of the second functional layer 22 away from the anode 11;

[0058] The first functional layer 21 is a P-type organic semiconductor layer, and the second functional layer 22 is an N-type organic semiconductor layer. The first functional layer 21 and the second functional layer 22 are used to form a PN junction structure. Under forward voltage, the PN junction structure is used as a carrier transport functional layer. Under reverse voltage, the PN junction structure is used as a photodetector functional layer.

[0059] The technical solution provided by this invention embeds the P-type and N-type organic semiconductor layers of the OPD inside the OLED as the first functional layer 21 and the second functional layer 22, respectively. The first functional layer 21 and the second functional layer 22 can promote carrier recombination under forward bias, thus facilitating light emission from the composite device, and can also form a depletion region under reverse bias, thus facilitating photodetection of the composite device. This allows the same structure to achieve display and detection functions under different biases. Integrating the OPD and OLED to form a composite device and applying it to a display screen can significantly improve the integration density and reduce the size of the display screen. Furthermore, it allows the effective photosensitive area and the light-emitting area in the display screen to be shared, thereby increasing the area of ​​the effective photosensitive area and improving the resolution of the display panel. In addition, the display and detection functions of the composite device are used at different times, thus preventing signal interference between the detection signal and the light-emitting driving signal and improving the signal-to-noise ratio of the detector. The emission wavelength and detection spectrum range can be adjusted by material selection, providing design flexibility.

[0060] Furthermore, in related technologies, OLEDs and OPDs are arranged side-by-side, requiring the precise deposition of different organic materials in two adjacent tiny pixel regions. This places extremely high demands on the alignment accuracy of the FMM (Fine Metal Mask), increasing the process difficulty and product defect rate. Moreover, the film deposition, patterning, and electrode lead-out processes for OLEDs and OPDs need to be performed alternately or repeatedly, making the entire process lengthy and impacting production efficiency and yield. In this invention, the organic material layers in the OLED and OPD are sequentially stacked in the vertical direction, allowing for electrode sharing. Furthermore, some film layers can be deposited using the same mask, thereby reducing the process complexity and manufacturing cost of the display. The composite device provided by this invention can be used in scenarios requiring compact design and interactive functions, such as smartwatches, wearable devices, and biosensors, and has broad application prospects.

[0061] The above are the core inventive points of this invention. The structure of the composite device with sensing and display functions will be specifically described below with reference to the accompanying drawings.

[0062] refer to Figure 1 The first functional layer 21 contains at least one hole transport material; the hole transport material is an electron-rich organic semiconductor material, and the highest occupied molecular orbital energy level of the hole transport material is below -5.0 eV. Under forward voltage, the first functional layer 21 is used to transport holes injected by the anode 11 to the light-emitting layer 30; under reverse voltage, the first functional layer 21 is used to absorb light to generate excitons, and based on the built-in electric field between it and the second functional layer 22, to split the excitons into electrons and holes.

[0063] The second functional layer 22 includes at least one electron transport material, which is an electron-deficient organic semiconductor material; the lowest unoccupied molecular orbital energy level of the electron transport material is between -4.0 eV and -3.5 eV; under forward voltage, the second functional layer 22 is used to transport electrons injected by the cathode 11 to the light-emitting layer 30; under reverse voltage, the second functional layer 22 is used to absorb light to generate excitons, and based on the built-in electric field between it and the first functional layer 21, to split the excitons into electrons and holes.

[0064] Specifically, Figure 2 yes Figure 1 The diagram shown illustrates the operation of the structure under forward voltage. (Refer to...) Figure 2 When the composite device is used as an OLED, a forward voltage is applied to the device, i.e., anode 11 is connected to the positive terminal of the power supply, cathode 12 is connected to the negative terminal, and the electric field direction is from anode 11 to cathode 12. At this time, the electric field drives the charge carriers as follows: holes (positive charges) migrate towards cathode 12 along the electric field direction, and electrons (negative charges) migrate towards anode 11 against the electric field direction. They eventually meet and recombine in the light-emitting layer 30, forming excitons (electron-hole pairs). The excitons transition from the excited state back to the ground state, releasing energy as photons, thus emitting light. Therefore, under a forward voltage, the first functional layer 21 acts as a hole transport layer, transferring holes injected from anode 11 to the light-emitting layer 30; the second functional layer 22 acts as an electron transport layer, transferring electrons injected from cathode 12 to the light-emitting layer 30.

[0065] The first functional layer 21 comprises at least one hole transport material, which is an electron-rich organic semiconductor material. Setting the highest occupied molecular orbital energy level of the hole transport material below -5.0 eV reduces the deviation between the work function of the anode 11 and the highest occupied molecular orbital energy level of the first functional layer 21, making their energy levels more closely matched and facilitating hole injection from the anode 11 into the first functional layer 21. The second functional layer 22 comprises at least one electron transport material, which is an electron-deficient organic semiconductor material. Setting the lowest unoccupied molecular orbital energy level of the electron transport material between -4.0 eV and -3.5 eV reduces the deviation between the work function of the cathode 12 and the lowest unoccupied molecular orbital energy level of the second functional layer 22, making their energy levels more closely matched and facilitating electron injection from the cathode 12 into the second functional layer 22.

[0066] Figure 3 yes Figure 1 The diagram shown illustrates the operation of the structure under reverse voltage. (Refer to...) Figure 3When the composite device is used as an OPD, it receives a reverse voltage, meaning the anode 11 is connected to the negative terminal of the power supply and the cathode 12 is connected to the positive terminal. Both the first functional layer 21 and the second functional layer 22 serve as light-absorbing layers. Under illumination, these layers absorb light of their respective target wavelengths, generating excitons. The first functional layer 21 and the second functional layer 22 form a pn heterojunction. Through the built-in electric field of the pn heterojunction, the excitons are split into free holes and electrons. Ultimately, the holes are collected by the anode 11, and the electrons are collected by the cathode 12, forming a photocurrent (the direction of the photocurrent is consistent with the direction of the reverse voltage).

[0067] Therefore, the hole transport material of the first functional layer 21 possesses both hole transport and light absorption properties; similarly, the electron transport material of the second functional layer 22 possesses both electron transport and light absorption properties. The hole transport material of the first functional layer 21 can be primarily composed of conjugated polymers, thus achieving a balance between light absorption and solubility (facilitating solution film formation). For example, the hole transport material of the first functional layer 21 can be a polythiophene derivative, capable of absorbing visible light; it can also be a polyfluorene derivative, capable of absorbing near-infrared light, suitable for infrared detection. The electron transport material of the second functional layer 22 can be primarily composed of materials with high electron affinity, facilitating electron reception. For example, the electron transport material of the second functional layer 22 can be a fullerene derivative, capable of forming a highly efficient heterojunction with p-type polymers; it can also be a non-fullerene material: exhibiting good near-infrared absorption and superior stability compared to fullerene derivatives.

[0068] Further reference Figure 1 The material of the first functional layer 21 includes one or more of conjugated olefins, aromatic rings, pentacene, poly(3-hexylthiophene), and copper phthalocyanine. The material of the second functional layer 22 includes fullerene C. 60 Fullerene C 70 One or more of the following: perylene tetracarboxylic dianhydride (PTCDA) and N,N'-dioctyl-3,4,9,10-perylene diimide.

[0069] Based on the above embodiments, optionally, the light-emitting layer 30 includes: a light-emitting material layer; and at least one of a hole transport layer and an electron blocking layer located between the light-emitting material layer and the first functional layer, and / or at least one of an electron transport layer and a hole blocking layer located between the light-emitting material layer and the second functional layer.

[0070] Figure 4 This is a schematic diagram of another composite device with sensing and display functions provided in an embodiment of the present invention, for reference. Figure 4An exemplary illustration shows that the light-emitting layer 30 includes: a light-emitting material layer 31, a hole transport layer 32 and an electron blocking layer 34 located between the light-emitting material layer 31 and the first functional layer 21, and an electron transport layer 33 and a hole blocking layer 35 located between the light-emitting material layer 31 and the second functional layer 22.

[0071] Specifically, the luminescent material layer 31 is the core layer of the device, where photons are generated. The luminescent material layer 31 consists of a host material and dopants. Electrons and holes meet and recombine in this layer to form excitons, which emit light when de-excited. By selecting dopant materials with different emission wavelengths, the device can precisely control the emission of red, green, blue, or other colors of light. The host material possesses excellent carrier transport capabilities and a high triplet energy level (preventing energy from being transferred back to the guest).

[0072] The hole transport layer (HTL) 32 is located between the first functional layer 21 and the light-emitting material layer 31. When the composite device is used as an OLED, the hole transport layer 32 is used to receive holes from the first functional layer 21 and efficiently transport them to the light-emitting material layer 31. The material of the hole transport layer 32 can be mainly triarylamine small molecules, which have the characteristics of high hole mobility and good stability. For example, the material of the hole transport layer 32 can be NPB (N,N'-diphenyl-N,N'-di(1-naphthyl)-1,1'-biphenyl-4,4'-diamine), whose hole mobility reaches... The material of hole transport layer 32 can also be TCTA (4,4',4''-tris(carbazole-9-yl)triphenylamine), which has both hole transport and exciton blocking functions.

[0073] An electron blocking layer (EBL) 34 is located between the hole transport layer 32 and the light-emitting material layer 31. When the composite device is used as an OLED, the electron blocking layer 34 is used to prevent electrons from leaking from the light-emitting material layer 31 to the hole transport layer 32. Confining electrons and holes within the light-emitting material layer 31 significantly improves the efficiency of the device.

[0074] An electron transport layer (ETL) 33 is located between the second functional layer 22 and the light-emitting material layer 31. When the composite device is used as an OLED, the electron transport layer 33 is used to receive electrons from the second functional layer 22 and efficiently transport them to the light-emitting material layer 31. The hole transport layer 32 can be made primarily of nitrogen-containing heterocyclic small molecules, which have the characteristics of high electron mobility and easy matching with the cathode 12. For example, the material of the electron transport layer 33 can be Alq3 (aluminum octahydroxyquinoline), which has a low cost. The material of the electron transport layer 33 can also be TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene), which has high electron mobility and is suitable for high-efficiency blue OLEDs.

[0075] A hole blocking layer (HBL) 35 is located between the electron transport layer 33 and the light-emitting material layer 31. When the composite device is used as an OLED, the hole blocking layer 35 is used to prevent holes from leaking from the light-emitting material layer 31 to the electron transport layer 33. Confining electrons and holes within the light-emitting material layer 31 significantly improves the efficiency of the device.

[0076] It should be noted that the materials of hole transport layer 32 and electron transport layer 33 have low light absorption coefficients or no light absorption properties, in order to avoid absorbing the light from light-emitting material layer 31 and reducing the luminous brightness of the composite device. Moreover, the materials of hole transport layer 32 and electron transport layer 33 do not participate in exciton formation, but are only used for transporting charge carriers.

[0077] Based on the above embodiments, refer to Figure 5 Optionally, the composite device also includes a hole injection layer (HIL) 41 located between the anode 11 and the first functional layer 21. The HOMO (Highest Occupied Molecular Orbital) energy level of the hole injection layer 41 is between the work function of the anode 11 and the HOMO of the first functional layer 21, thereby reducing the hole injection barrier and improving the hole injection efficiency.

[0078] Based on the above embodiments, refer to Figure 5 Optionally, the composite device also includes an electron injection layer (EIL) 42 located between the cathode 12 and the second functional layer 22. The LUMO (Lowest Unoccupied Molecular Orbital) energy level of the electron injection layer 42 is located between the work function of the cathode 12 and the LUMO of the second functional layer 22, thereby lowering the electron injection barrier and improving the electron injection efficiency.

[0079] Based on the above embodiments, optionally, the thickness of the light-emitting layer 30 is less than or equal to 50 nm to facilitate the separation of electrons and holes. Preferably, the thickness of the light-emitting layer 30 is less than or equal to 20 nm, thereby further facilitating the separation of electrons and holes.

[0080] Based on the above embodiments, in one embodiment of the present invention, reference is made to... Figure 6 The light-emitting device includes a substrate and, in sequence away from the substrate, an anode 11, a first functional layer 21, a hole transport layer 32, a light-emitting material layer 31, an electron transport layer 33, a second functional layer 22, and a cathode 12. The anode 11 is made of indium tin oxide (ITO); the first functional layer 21 is made of titanium copper (CuPC) with a thickness of 50 nm; the hole transport layer 32 is made of N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) with a thickness of 5 nm; the host material of the luminescent material layer 31 is bis(2-(2-phenol)pyridine)beryllium (Bepp2), and the guest material is tris(2-phenylpyridine)iridium (Ir(ppy)3), with a thickness of 5 nm; the electron transport layer 33 is a mixture of 4,7-diphenyl-1,10-phenanthroline (Bphen) and lithium 8-hydroxyquinoline (Liq) (with a thickness of 5 nm). The second functional layer 22 is made of fullerene C. 60 The thickness is 40 nm. The cathode 12 is made of Al.

[0081] Figure 7 yes Figure 6 The diagram shows the energy levels of the materials in each film layer of the structure shown, for reference. Figure 6 and Figure 7 When the composite device is used as an OLED, it receives a positive input voltage, meaning anode 11 is connected to the positive terminal of the power supply and cathode 12 is connected to the negative terminal. It should be noted that... Figure 7 All data shown are absolute values ​​of the HOMO and LUMO energy levels for each film layer. The energy level data noted in parentheses below are also absolute values ​​for that energy level.

[0082] For hole injection and transport: The work function of ITO is approximately 4.7 eV, which matches the HOMO level of CuPc (approximately 5.2 eV) (barrier ≈ 0.5 eV). Under the drive of a positive electric field, holes overcome the low barrier and are injected into the HOMO of the first functional layer 21 from the anode 11. The hole transport path is from the HOMO of CuPc (energy level approximately 5.2 eV) to the HOMO of NPB (energy level approximately 5.4 eV), and then to the HOMO of the luminescent material layer 31 Bepp2:Ir(ppy)3 (energy level approximately 6.2 eV). Among them, NPB is a highly efficient hole transport material, and the energy difference between its HOMO and CuPc's HOMO is only about 0.2 eV, allowing holes to transport without hindrance. There is a barrier of approximately 0.8 eV from NPB to Bepp2, but the positive electric field can drive holes to overcome the barrier and enter the luminescent material layer 31. For electron injection and transport: the work function of Al is approximately 4.1 eV, compared to C. 60 The LUMO energy level (approximately 4.0 eV) is close to the barrier (approximately 0.1 eV), allowing electrons to be easily injected from Al into C. 60 The LUMO. The electron transport path is from C... 60 The energy levels range from the initial LUMO (approximately 4.0 eV) of Bphen:Liq to the LUMO of Bepp2:Ir(ppy)3 (approximately 3.1 eV), and finally to the LUMO of Bepp2:Ir(ppy)3 with a luminescent material layer. Bphen is a good electron transport material, while Liq doping reduces the Cg level. 60 The electron transport barrier to Bphen decreases from 1.2 eV to about 1.0 eV; there is no energy difference (-0.3 eV) between the LUMO of Bphen (energy level about 2.8 eV) and the LUMO of Bepp2 (energy level about 3.1 eV), allowing electrons to be smoothly injected into the luminescent material layer 31.

[0083] Electrons and holes meet in the luminescent material layer 31 and combine through Coulomb forces to form excitons. Bepp2 serves as the host material, and its HOMO and LUMO properties form a potential well, confining holes and electrons within the luminescent material layer 31 and increasing the recombination probability. The phosphorescent dye Ir(ppy)3 efficiently captures excitons through energy transfer or direct carrier capture. Its excitons can release energy through spin-allowed triplet transitions, i.e., the exciton transitions from the excited state back to the ground state, and the released energy is radiated in the form of photons, emitting green light.

[0084] For example, Figure 8 This is a schematic diagram of the voltage-current density-brightness characteristic curves of a composite device with sensing and display functions provided in an embodiment of the present invention under forward voltage. (Refer to...) Figure 8When the forward voltage is greater than 9V, the brightness of the composite device increases with the increase of the forward voltage. When the forward voltage is greater than 0V, the current density flowing through the composite device increases with the increase of the voltage. Moreover, when the voltage is between 8V and 10V, the current density increases at a relatively high rate with the increase of the voltage. Figure 9 This is a schematic diagram of the current efficiency-brightness characteristic curve of a composite device with sensing and display functions provided in an embodiment of the present invention under forward voltage. (Refer to...) Figure 9 The brightness of the composite device increases with the increase of current efficiency.

[0085] Please continue to refer to this. Figure 6 and Figure 7 When the composite device is used as an OPD, it receives a reverse voltage, meaning anode 11 is connected to the negative terminal of the power supply and cathode 12 is connected to the positive terminal. In the absence of light, the device is not externally excited and only exhibits dark current (caused by a small number of intrinsic carriers or leakage current), the magnitude of which is determined by the difficulty of carrier injection and the transport barrier. Using a method such as... Figure 6 In the structure shown, carrier injection is almost impossible, and internal transport is hindered. ITO injects electrons into the LUMO of CuPc, but due to the 1.6 eV difference between the work function of ITO (approximately 4.7 eV) and the energy level of the LUMO of CuPc (approximately 3.1 eV), the potential barrier is high, preventing electron injection. Al injects electrons into C... 60 HOMO injection of holes, but due to the work function of Al (4.1 eV) and C 60 The energy difference between the HOMO levels (approximately 6.0 eV) is 1.9 eV, creating a high barrier that prevents hole injection. Even with a small number of intrinsic carriers (e.g., those generated by thermal excitation), transport paths are blocked by this high barrier. Holes in CuPc and / or NPB need to move towards ITO. Although the HOMO barrier from NPB to CuPc is only about 0.2 eV, facilitating hole transport, the barrier from CuP to ITO is approximately 0.5 eV, which must be overcome. Electrons in C60 and / or Bphen layers need to move towards Al. Electrons from C… 60 The barrier from the LUMO (energy level approximately 4.0 eV) of Al to the LUMO (energy level approximately 2.8 eV) of Bphen is 1.2 eV, making it difficult to reach Al. Therefore, in the absence of light, the dark current under reverse voltage is extremely small, approximately in the nA range, and the device has almost no effective current output, with only a weak leakage current.

[0086] Please continue to refer to this. Figure 6 and Figure 7When the composite device is used as an OPD (Optical Distribution Device) and is illuminated, it can detect optical signals and generate photocurrents. The specific process includes: a) the first functional layer 21 and the second functional layer 22 absorb light and generate excitons; specifically, the active material CuPc (as a donor) absorbs visible light, especially red and near-infrared light; C 60 (As an acceptor) it absorbs ultraviolet, violet, and blue light. After the photon energy is absorbed, the material molecules transition from the ground state to the excited state, forming excitons. b. Charge separation, generating photogenerated carriers; specifically, excitons separate at the donor-acceptor interface (such as the CuPc-NPB interface, C60-Bphen interface) or inside the material; in CuPc, excitons separate into holes and electrons, with holes remaining in the HOMO of CuPc and electrons transferring to the LUMO of NPB. Since the energy level of the LUMO of CuPc (approximately 3.1 eV) is higher than that of the LUMO of NPB (approximately 2.4 eV), electrons are more easily transferred; in C60, excitons separate into electrons and holes, with electrons remaining in the LUMO of C60 and holes transferring to the HOMO of Bphen. 60 The HOMO energy level of the HOMO (approximately 6.0 eV) is lower than that of the HOMO energy level of the Bphen, thus facilitating hole transfer. c. Under the drive of a reverse electric field, charge carriers are transported and collected; specifically, holes move towards ITO and are ultimately collected by ITO; electrons move towards Al and are ultimately collected by Al. Therefore, under negative illumination, photogenerated charge carriers are efficiently separated and collected by the electrodes under a reverse electric field, forming a forward photocurrent (in the same direction as the reverse voltage), and the composite device exhibits the photoelectric detection characteristics of OPD.

[0087] Figure 10 This is a comparison graph of the current density versus voltage curves of a composite device under illumination and without illumination, provided by an embodiment of the present invention. (Refer to...) Figure 10 Interval Q1 represents the current density versus voltage curve when a reverse voltage is applied to the composite device under illumination of 500 nits, while interval Q2 represents the current density versus voltage curve when a reverse voltage is applied to the composite device under no illumination. Figure 10 It can be seen that in the absence of light, the dark current under reverse voltage is extremely small, approximately on the order of nA, and the device has almost no effective current output, with only a weak leakage current. Under negative illumination, photogenerated carriers are efficiently separated under the reverse electric field and collected by the electrodes, forming a photocurrent. The composite device exhibits the photoelectric detection characteristics of OPD.

[0088] Based on the above embodiments, optionally, the range of the forward voltage applied to the composite device is 3V~15V; and the range of the reverse voltage applied to the composite device is 0.1V~10V.

[0089] This invention also provides a display screen. Figure 11 This is a partial structural diagram of a display screen provided in an embodiment of the present invention, for reference. Figure 11 ,include:

[0090] Multiple sub-pixels P, wherein at least some of the sub-pixels P employ a composite device with sensing and display functions as described in any embodiment of the present invention;

[0091] The driving circuit layer 02 includes a plurality of driving circuit units 200, each driving circuit unit 200 being electrically connected to a sub-pixel P; wherein the driving circuit unit 200 electrically connected to the composite device is used to apply a positive voltage or a reverse voltage to the composite device.

[0092] The control module is used to switch the voltage direction of the drive circuit unit 200 to switch between the display working mode and the detection working mode of the composite device.

[0093] Specifically, the display area of ​​the screen includes an array substrate and a light-emitting device layer disposed on the array substrate. The light-emitting device layer includes multiple sub-pixels P, which can be arranged in an array. At least some of the sub-pixels P employ composite devices with sensing and display functions as described in any embodiment of the present invention. It can be understood that all sub-pixels P can be set as composite devices, or only some of the sub-pixels P can be set as composite devices. When some of the sub-pixels P are set as composite devices, the composite devices can be concentrated in the same area of ​​the display screen, or the composite devices can be distributed throughout the display area according to a preset pattern.

[0094] An array substrate refers to a film layer structure that provides driving signals to a display screen and serves functions such as buffering, protection, or support. It includes a substrate 01 and a driving circuit layer 02 disposed on the substrate 01. The driving circuit layer 02 includes multiple driving circuit units 200, each of which is electrically connected to a sub-pixel P to drive the sub-pixel P to emit light. The driving circuit unit 200 connected to the composite device can apply either a forward voltage or a reverse voltage to the composite device. The control module, which can be a driving chip, is used to switch the voltage direction of the driving circuit unit 200, thereby switching the display operating mode and the detection operating mode of the composite device.

[0095] In one embodiment of the present invention, optionally, the driving circuit layer 02 may further include multiple data signal lines, multiple scan signal lines, multiple light emission control signal lines, and multiple power supply lines. The driving circuit unit 200 can be a conventional pixel circuit such as a "2T1C" circuit, a "7T1C" circuit, or an "8T1C" circuit. The pixel circuit is connected to the scan signal lines, light emission control signal lines, data signal lines, and power supply lines, respectively. The data signal lines are configured to provide data voltage to the pixel driving circuit unit 200, the scan signal lines are configured to provide scan signals to the driving circuit unit 200, the light emission control signal lines are configured to provide light emission control signals to the driving circuit unit 200, and the power supply lines are configured to provide anode voltage to the driving circuit unit 200, thereby realizing the light emission control of conventional sub-pixels P, as well as the light detection and light emission control of sub-pixels P using composite devices.

[0096] The display screen provided in this embodiment of the invention includes: a plurality of sub-pixels P, wherein at least some of the sub-pixels P employ a composite device with sensing and display functions as described in any embodiment of the invention; a driving circuit layer 02, including a plurality of driving circuit units 200, each driving circuit unit 200 being electrically connected to a corresponding sub-pixel P; wherein the driving circuit unit 200 electrically connected to the composite device is used to apply a positive voltage or a reverse voltage to the composite device; and a control module, used to switch the voltage direction of the driving circuit units 200 to realize the switching between the display working mode and the detection working mode of the composite device. In display mode, the image is refreshed; in detection mode, light signals are collected. The two functions can be operated in parallel through high-frequency time-division multiplexing. The display screen can be widely used in fields such as intelligent interactive display, biosensing, and ambient light monitoring.

[0097] Based on the above embodiments, refer to Figure 11 Optionally, the display screen includes multiple pixel units arranged in an array, each pixel unit including sub-pixels of different colors. Each pixel unit may include a first color sub-pixel, a second color sub-pixel, and a third color sub-pixel. For example, the first color sub-pixel is a red sub-pixel R, the second color sub-pixel is a green sub-pixel G, and the third color sub-pixel is a blue sub-pixel B. The red sub-pixel R emits red light, the green sub-pixel G emits green light, and the blue sub-pixel B emits blue light. By adjusting the brightness of the red sub-pixel R, the green sub-pixel G, and the blue sub-pixel B, different colors can be displayed.

[0098] In each pixel unit, at least one sub-pixel can be configured as a composite device. For example, the red sub-pixel R in each pixel unit can be configured as a composite device, or the blue sub-pixel B in each pixel unit can be configured as a composite device, or the green sub-pixel G in each pixel unit can be configured as a composite device. Configuring sub-pixels of the same color as composite devices can reduce the difficulty of display fabrication. Figure 11 In the exemplary illustration of a pixel unit, the red sub-pixel R, the green sub-pixel G, and the blue sub-pixel B are all configured as composite devices.

[0099] Based on the above embodiments, please continue to refer to Figure 11 Optionally, the display screen also includes a pixel definition layer 03 located between two adjacent sub-pixels P, which can physically define and isolate each individual sub-pixel. The pixel definition layer 03 is made of an insulating material (such as polyimide or acrylic resin), which effectively isolates the anode 11 and the light-emitting material layer 31 between adjacent sub-pixels P, preventing driving current from flowing from one sub-pixel P to another, thereby avoiding unintended light emission or uneven brightness. In this embodiment of the invention, the thickness of the pixel definition layer 03 is greater than or equal to 2 μm, which can further avoid lateral light crosstalk and leakage current problems.

[0100] Based on the above embodiments, optionally, in the display operating mode, the positive voltage applied by the driving circuit unit 200 to the composite device ranges from 3V to 15V. In the composite device, the first functional layer 21 is used to inject holes into the light-emitting layer 30, and the second functional layer 22 is used to inject electrons into the light-emitting layer 30, so that holes and electrons recombine in the light-emitting layer 30 to emit light. With a positive voltage of 3V to 15V applied, the composite device operates in the standard OLED mode. The starting voltage of around 3V ensures that the device can be effectively turned on (typically higher than the bandgap voltage of the semiconductor material), and the maximum driving capability of 15V ensures that when high brightness output is required (such as in strong outdoor light environments or HDR displays), there is sufficient driving margin to excite the device to reach its maximum brightness without brightness saturation.

[0101] In the detection mode, the reverse voltage applied by the driving circuit unit 200 to the composite device ranges from 0.1V to 10V. In the composite device, the first functional layer 21 and the second functional layer 22 are used to detect optical signals and convert them into electrical signals. Applying a reverse voltage of 0.1V to 10V allows detection to begin from such an extremely low voltage as 0.1V, meaning that the device consumes very little power in detection mode. Setting the upper limit of the reverse voltage to 10V ensures that it is below the avalanche breakdown voltage of a typical semiconductor PN junction, guaranteeing the long-term stability and reliability of the device in detection mode and preventing damage due to high voltage.

[0102] Based on the above embodiments, optionally, the control module is configured to control the composite device to switch between display mode and detection mode, and adjust its operating frequency accordingly; the display mode corresponds to a first frequency range; the detection mode corresponds to a second frequency range; wherein the lower limit of the first frequency range is higher than or equal to the upper limit of the second frequency range. The control module includes a "detection-feedback" closed-loop transmission channel, and the detection signal is fed back to the display screen body in real time to achieve adaptive response to ambient light.

[0103] Specifically, in display mode, the control module controls the drive circuit to apply a positive voltage to the composite device within a first frequency range to refresh the image; this frequency range corresponds to the image refresh rate. In detection mode, the control module controls the drive circuit to apply a reverse voltage to the composite device within a second frequency range to read its photocurrent; this frequency range corresponds to the sampling rate of the detection data. A specific numerical embodiment is as follows: the first frequency range is 60Hz~240Hz; the second frequency range is 1Hz~60Hz. By setting the lower limit of the first frequency range to be higher than or equal to the upper limit of the second frequency range, the display screen can maintain a high refresh rate while displaying high-quality dynamic content, and perform high-speed, high-precision optical detection without sacrificing display smoothness for detection.

[0104] This invention also provides an electronic device, including a display screen as described in any embodiment of the invention. The display screen is configured to both emit display light to achieve a display function and receive external light to achieve a light detection function. The electronic device can be a smartphone, smartwatch, smart bracelet, smart glasses, or a patch-type biosensor. These devices have the same technical effects and will not be described further here.

[0105] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A composite device with sensing and display functions, characterized in that, include: anode; The first functional layer is located on one side of the anode; The light-emitting layer is located on the side of the first functional layer away from the anode; The second functional layer is located on the side of the light-emitting layer away from the anode; The cathode is located on the side of the second functional layer away from the anode; Wherein, the first functional layer is a P-type organic semiconductor layer, and the second functional layer is an N-type organic semiconductor layer; the first functional layer and the second functional layer are used to form a PN junction structure; under forward voltage, the PN junction structure is used as a carrier transport functional layer; under reverse voltage, the PN junction structure is used as a photodetector functional layer.

2. The composite device with sensing and display functions according to claim 1, characterized in that, The first functional layer includes at least one hole transport material; the hole transport material is an electron-rich organic semiconductor material, and the highest occupied molecular orbital energy level of the hole transport material is below -5.0 eV; Under the forward voltage, the first functional layer is used to transfer the holes injected by the anode to the light-emitting layer; under the reverse voltage, the first functional layer is used to absorb light to generate excitons, and based on the built-in electric field between itself and the second functional layer, to split the excitons into electrons and holes. Preferably, the material of the first functional layer includes one or more of conjugated olefins, aromatic rings, pentacene, poly(3-hexylthiophene), and copper phthalocyanine.

3. The composite device with sensing and display functions according to claim 1, characterized in that, The second functional layer includes at least one electron transport material, which is an electron-deficient organic semiconductor material; the lowest unoccupied molecular orbital energy level of the electron transport material is between -4.0 eV and -3.5 eV; Under the forward voltage, the second functional layer is used to transfer electrons injected by the cathode to the light-emitting layer; under the reverse voltage, the second functional layer is used to absorb light to generate excitons and, based on the built-in electric field between itself and the first functional layer, split the excitons into electrons and holes. Preferably, the material of the second functional layer includes fullerene C 60 Fullerene C 70 One or more of perylene tetracarboxylic dianhydride (PTCDA) and N,N'-dioctyl-3,4,9,10-perylene diimide.

4. The composite device with sensing and display functions according to claim 1, characterized in that, The light-emitting layer includes: a light-emitting material layer, at least one of a hole transport layer and an electron blocking layer located between the light-emitting material layer and the first functional layer, and at least one of an electron transport layer and a hole blocking layer located between the light-emitting material layer and the second functional layer; And / or, the composite device further includes a hole injection layer located between the anode and the first functional layer; And / or, the composite device further includes an electron injection layer located between the cathode and the second functional layer.

5. The composite device with sensing and display functions according to any one of claims 1 to 4, characterized in that, The thickness of the light-emitting layer is less than or equal to 50 nm.

6. A display screen, characterized in that, include: Multiple sub-pixels, wherein at least some of the sub-pixels employ a composite device with sensing and display functions as described in any one of claims 1 to 5; The driving circuit layer includes multiple driving circuit units, each driving circuit unit being electrically connected to one of the sub-pixels; wherein the driving circuit unit electrically connected to the composite device is used to apply a positive voltage or a reverse voltage to the composite device. The control module is used to switch the voltage direction of the drive circuit unit to switch the display mode and the detection mode of the composite device.

7. The display screen according to claim 6, characterized in that, Also includes: A pixel definition layer is located between two adjacent sub-pixels; the thickness of the pixel definition layer is greater than or equal to 2 μm.

8. The display screen according to claim 6, characterized in that, In the display operating mode, the positive voltage applied by the driving circuit unit to the composite device is in the range of 3V~15V; in the composite device, the first functional layer is used to inject holes into the light-emitting layer, and the second functional layer is used to inject electrons into the light-emitting layer, so that the holes and the electrons recombine and emit light in the light-emitting layer; In the detection mode, the reverse voltage applied by the driving circuit unit to the composite device ranges from 0.1V to 10V; in the composite device, the first functional layer and the second functional layer are used to detect optical signals and convert the optical signals into electrical signals.

9. The display screen according to claim 6, characterized in that, The control module is configured to control the composite device to switch between display mode and detection mode, and adjust its operating frequency accordingly. The display working mode corresponds to the first frequency range; The detection mode corresponds to the second frequency range; Wherein, the lower limit of the first frequency range is higher than or equal to the upper limit of the second frequency range; Preferably, the first frequency range is 60Hz to 240Hz; the second frequency range is 1Hz to 60Hz.

10. An electronic device, characterized in that, Includes the display screen as described in any one of claims 6 to 9; The display screen is configured to both emit display light to achieve the display function and receive external light to achieve the light detection function.

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