A layered switchable color OLED device structure and a preparation method thereof

Abstract

This invention discloses an OLED device structure and its fabrication method with layered color switching, belonging to the field of OLED display technology. The structure includes a silicon substrate, an anode layer, a cathode layer, an organic functional layer, an encapsulation layer, and a cover glass. The organic functional layer comprises a first light-emitting unit, an intermediate electrode layer, and a second light-emitting unit stacked sequentially. The intermediate electrode layer is a composite structure of metal and transparent conductive oxide, capable of switching the power supply polarity. By controlling the power supply state of each electrode, the two light-emitting units can be independently or in series lit, achieving layered color switching. The fabrication method is compatible with existing OLED industrialization processes, eliminating the need for color filter fabrication, increasing pixel aperture ratio, reducing driving voltage and power consumption, minimizing optical loss, and extending device lifespan. It offers flexible color switching to adapt to different display needs; the process is simplified, yield is high, and cost is low, adapting to ultra-high pixel densities of ≥3000 PPI, meeting the requirements of AR / VR near-eye display scenarios.

Description

Technical Field

[0001] This invention relates to the field of OLED display technology, and more specifically, to an OLED device structure and its fabrication method that can switch light colors in layers. Background Technology

[0002] OLEDoS display technology is a new type of micro-display technology that integrates the self-emissive characteristics of OLED with the precision driving capabilities of silicon-based semiconductors. Its core advantage lies in the ability to achieve ultra-high pixel density (PPI) by relying on silicon-based CMOS driving circuits. It has become the core technical solution for AR / VR near-eye displays to achieve retinal-level visual effects. Currently, the pixel density requirement for this type of scenario has reached over 4000 PPI.

[0003] To circumvent the manufacturing limitations of fine metal masks (FMMs) in ultra-high resolution fabrication, such as low process precision and poor yield, existing OLEDoS display technologies generally adopt a multi-layered emission + color filter approach to achieve RGB color separation. However, when this approach is applied to non-full-color display scenarios, it exposes many intractable technical defects:

[0004] 1. Color filter requires a separate pixel area for RGB monochromatic light, which greatly reduces the bottom pixel aperture ratio. The device needs to withstand a higher current density when it is working, which not only aggravates device loss, but also significantly shortens its lifespan.

[0005] 2. Traditional stacked light emission is a multi-layer full-color light emission structure. The resistance to charge transmission in the multi-layer film is greatly increased, which directly leads to a higher driving voltage of the device and increases the power consumption of the display device, which does not meet the low power consumption requirements of AR / VR devices.

[0006] 3. Color filter method will cause more than 50% optical loss. In order to ensure display brightness, the driving current needs to be further increased to compensate for the brightness, forming a vicious cycle of optical loss-brightness compensation-increased power consumption-aggravated device loss, and the pressure of brightness compensation is extremely high. Summary of the Invention

[0007] The purpose of this invention is to provide an OLED device structure and its fabrication method that can switch light colors in layers, so as to solve the technical problems existing in the background art.

[0008] The present invention provides an OLED device structure that can switch light colors in layers, including a silicon substrate, an anode layer, a cathode layer, an organic functional layer, an encapsulation layer, and a cover glass. A CMOS driving circuit is integrated on the surface of the silicon substrate. The anode layer, organic functional layer, cathode layer, encapsulation layer, and cover glass are stacked sequentially along the light emission direction of the silicon substrate. The organic functional layer includes a first light-emitting unit, an intermediate electrode layer, and a second light-emitting unit stacked sequentially along the light emission direction.

[0009] The first light-emitting unit is disposed between the anode layer and the intermediate electrode layer, and the second light-emitting unit is disposed between the intermediate electrode layer and the cathode layer. The first light-emitting unit and the second light-emitting unit are respectively provided with light-emitting layers that emit light with different peak wavelengths. The intermediate electrode layer is a conductive layer structure composed of metal and transparent conductive oxide. The anode layer, the intermediate electrode layer, and the cathode layer are all electrically connected to the CMOS driving circuit. The intermediate electrode layer can switch the power supply polarity to work as an anode or a cathode through the CMOS driving circuit. By controlling the power supply state of the anode layer, the intermediate electrode layer, and the cathode layer, the first light-emitting unit or the second light-emitting unit can be selectively lit to achieve layered switching of the light color emitted by the device.

[0010] In a preferred embodiment, the first light-emitting unit includes a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, and a first electron injection layer stacked sequentially along the light emission direction; the second light-emitting unit includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and a second electron injection layer stacked sequentially along the light emission direction.

[0011] In a preferred embodiment, the first light-emitting layer and the second light-emitting layer emit light of any two different colors selected from red, green, blue, yellow, and white light; the first light-emitting unit and the second light-emitting unit can be lit simultaneously to achieve mixed light emission of the two colors.

[0012] In a preferred embodiment, the metal layer of the intermediate electrode layer is selected from any one of Ag layer, Al layer, and Mg:Ag alloy layer, and has a thickness of 5nm-30nm; the transparent conductive oxide layer is selected from any one of ITO layer and IZO layer, and has a thickness of 10nm-100nm; the metal layer is disposed on the side close to the first light-emitting unit, and the transparent conductive oxide layer is disposed on the side close to the second light-emitting unit.

[0013] In a preferred embodiment, the anode layer is a high-reflectivity composite anode, selected from any one of ITO / Ag / ITO stacked structure and Ag-based composite anode, with a total thickness of 50nm-200nm; the cathode layer is a semi-transparent conductive cathode, selected from any one of Mg:Ag alloy layer, ultrathin Ag layer, and ITO / Ag / ITO composite cathode, with a thickness of 5nm-50nm.

[0014] In a preferred embodiment, the CMOS driving circuit controls the light color switching of the device in three modes: Mode 1, the intermediate electrode layer is configured as a cathode, a positive driving voltage is applied to the anode layer, the cathode layer is suspended, only the first light-emitting unit is lit, and the device emits the first light color; Mode 2, the intermediate electrode layer is configured as an anode, a negative driving voltage is applied to the cathode layer, the anode layer is suspended, only the second light-emitting unit is lit, and the device emits the second light color; Mode 3, a positive driving voltage is applied to the anode layer, a negative driving voltage is applied to the cathode layer, the intermediate electrode layer is suspended, the first light-emitting unit and the second light-emitting unit are lit in series, and the device emits a mixed light color.

[0015] In a preferred embodiment, the silicon substrate is a single-crystal silicon substrate, and the pixel density of the CMOS driving circuit integrated on its surface is ≥3000 PPI.

[0016] In a preferred embodiment, the encapsulation layer is a composite thin-film encapsulation structure with alternating inorganic and organic layers, comprising at least two inorganic barrier layers and at least one organic planarization layer; the inorganic barrier layers are selected from any one of SiNx, SiO2, and Al2O3, with a single-layer thickness of 50nm-500nm; the organic planarization layer is selected from acrylate or polyimide materials, with a single-layer thickness of 1μm-10μm; the water and oxygen permeability of the encapsulation layer is ≤1×10^-6g / (m²・day).

[0017] A method for fabricating an OLED device structure capable of layered color switching, comprising the following steps:

[0018] S1 Substrate Pretreatment: Select a single-crystal silicon substrate with CMOS driving circuit integrated on its surface, and perform ultrasonic cleaning with organic solvent, rinsing with deionized water, drying with nitrogen gas in sequence, and then oxygen plasma activation treatment to complete the substrate pretreatment.

[0019] S2 Anode Layer Preparation: A conductive anode film is deposited on the pretreated substrate surface using physical vapor deposition. The patterning is completed by photolithography, development, and etching processes to form an anode layer that is electrically connected to the CMOS driving circuit.

[0020] S3 First Light-Emitting Unit Preparation: In a vacuum chamber with a vacuum degree ≤5×10^-4Pa, a vacuum thermal evaporation process is used to sequentially prepare the first hole injection layer, the first hole transport layer, the first light-emitting layer, the first electron transport layer and the first electron injection layer on the surface of the anode layer to complete the preparation of the first light-emitting unit;

[0021] S4 intermediate electrode layer fabrication: Maintaining a vacuum environment, a metal conductive layer is prepared using a vacuum thermal evaporation process, and then a transparent conductive oxide layer is prepared using an electron beam evaporation process to form an intermediate electrode layer. Electrical connection with the CMOS driving circuit is achieved through a patterning process.

[0022] S5 Second Light-Emitting Unit Fabrication: Maintaining a vacuum environment, a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and a second electron injection layer are sequentially fabricated on the surface of the intermediate electrode layer using a vacuum thermal evaporation process to complete the fabrication of the second light-emitting unit;

[0023] S6 Cathode Layer and Packaging Fabrication: The cathode layer is prepared using a vacuum thermal evaporation process, followed by an inorganic / organic composite packaging layer prepared using chemical vapor deposition and inkjet printing processes. Finally, the cover glass is bonded to complete the device fabrication.

[0024] The beneficial effects of the technical solution of this invention are:

[0025] This invention abandons the color filter structure and achieves color switching without a color filter by switching electrode polarity. This significantly improves pixel aperture ratio, reduces driving voltage by over 28%, and lowers power consumption by 40% at standard brightness, fundamentally reducing optical losses by over 50%. It breaks the vicious cycle of brightness compensation, increases device lifespan by over 40%, and greatly improves core optoelectronic performance and operational stability. Simultaneously, the CMOS driving circuit enables three-mode switching: independent illumination of two monochromatic lights and cascaded illumination of mixed colors. This solves the problem of fixed light color in conventional solutions. The composite electrode layer further ensures the stability of light color switching and avoids color difference problems caused by color filters. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the stacked cross-section of a conventional OLED device structure with multiple layers and a color filter in the prior art.

[0027] Figure 2 This is a schematic cross-sectional view of the stacked structure of the OLED device with layered color switching according to the present invention.

[0028] Explanation of reference numerals in the attached figures: 1 Substrate, 2 Anode, 3 First hole injection layer, 4 First hole transport layer, 5 First light-emitting layer, 6 First electron transport layer, 7 First electron injection layer, 8 Intermediate electrode layer, 9 Second hole injection layer, 10 Second hole transport layer, 11 Second light-emitting layer, 12 Second electron transport layer, 13 Second electron injection layer, 14 Cathode, 15 Encapsulation layer, 16 Cover glass. Detailed Implementation

[0029] The light emission direction described in this invention refers to the direction from the silicon substrate towards the cover glass. That is, the device of this invention is a top-emitting OLED structure, with light emanating from the cathode layer towards the cover glass. The vacuum environment described in this invention refers to a high vacuum environment with a vacuum level ≤ 5 × 10⁻⁴ Pa. This is to ensure the uniformity, density, and quality of the thin film deposition, and to avoid the influence of air impurities on the film performance. Materials, process equipment, and operating methods not specifically described in this invention, unless otherwise specified or limited, shall be implemented according to conventional methods in the OLED field.

[0030] Figure 1 The core fabrication steps of conventional stacked-layer + color filter OLED devices in existing technologies are as follows:

[0031] 1. Select a silicon substrate with surface-integrated CMOS driving circuitry and complete routine cleaning and activation pretreatment;

[0032] 2. The anode layer was prepared and patterned using physical vapor deposition (PVD) technology;

[0033] 3. A multi-layered RGB light-emitting functional layer is prepared using a vacuum thermal evaporation process;

[0034] 4. The color filter layer (RGB color separation filter layer) is prepared by coating, ultraviolet lithography, development and etching processes, which is a unique core process in conventional solutions;

[0035] 5. The encapsulation layer is prepared using chemical vapor deposition, and finally the cover glass is laminated to complete the device fabrication.

[0036] In the following embodiments, the same pixel density is used. Figure 1 Conventional stacked OLED devices with color filters serve as a control group. Under the same testing environment (25°C room temperature, standard driving current, darkroom optical testing), the aperture ratio, driving voltage, optical loss, device lifetime, and power consumption of the different pixel density devices of this invention are compared and tested.

[0037] Example 1: 4000PPI Red-Blue Dual-Color Switching OLED Device

[0038] like Figure 2 As shown, this solution provides a layered OLED device structure that can switch light colors, including a single-crystal silicon substrate 1 (with surface-integrated CMOS driving circuit, pixel density of 4000 PPI, suitable for high-end AR / VR near-eye displays), an anode layer 2, a cathode layer 14, an organic functional layer, an encapsulation layer 15, and a cover glass 16. Each layer is stacked sequentially along the light emission direction of the substrate 1. The organic functional layer includes a first light-emitting unit, an intermediate electrode layer 8, and a second light-emitting unit.

[0039] The first light-emitting unit is sandwiched between the anode layer 2 and the intermediate electrode layer 8, and is composed of a first hole injection layer 3, a first hole transport layer 4, a first blue light-emitting layer 5, a first electron transport layer 6, and a first electron injection layer 7 stacked sequentially. The second light-emitting unit is sandwiched between the intermediate electrode layer 8 and the cathode layer 14, and is composed of a second hole injection layer 9, a second hole transport layer 10, a second red light-emitting layer 11, a second electron transport layer 12, and a second electron injection layer 13 stacked sequentially. The intermediate electrode layer 8 is a composite structure of an Ag layer (10 nm thick) and an ITO layer (50 nm thick), with the Ag layer closer to the first light-emitting unit and the ITO layer closer to the second light-emitting unit; the anode layer 2 is an ITO / Ag / ITO stacked structure (total thickness 100 nm), and the cathode layer 14 is a Mg:Ag alloy layer (20 nm thick); the anode layer 2, the intermediate electrode layer 8, and the cathode layer 14 are all independently electrically connected to the CMOS driving circuit. The encapsulation layer 15 is an inorganic / organic alternating stacked structure of SiNx (100nm) + polyimide (5μm) + SiNx (100nm), with a water and oxygen permeability of 5×10^-7g / (m²・day).

[0040] The fabrication method of the above-mentioned device structure includes the following steps:

[0041] S1. Substrate pretreatment: Select a 4000PPI single crystal silicon substrate 1, and clean it with acetone and isopropanol for 15 minutes each, rinse it with deionized water for 5 minutes, and dry it with high-purity nitrogen; then activate it with oxygen plasma for 3 minutes at a power of 100W and an oxygen flow rate of 50sccm to complete the pretreatment.

[0042] S2. Anode layer preparation: ITO / Ag / ITO conductive thin film is deposited by magnetron sputtering (physical vapor deposition) process, and patterning is completed by ultraviolet lithography, development and dry etching to form anode layer 2 that is electrically connected to CMOS driving circuit.

[0043] S3. Fabrication of the first light-emitting unit: The substrate is transferred into a vacuum evaporation chamber and evacuated to 3×10^-4 Pa. Vacuum thermal evaporation process is used to sequentially deposit the first hole injection layer 3 (PEDOT:PSS, 20nm), the first hole transport layer 4 (NPB, 40nm), the first blue light emitting layer 5 (DPVBi, 30nm), the first electron transport layer 6 (TPBi, 30nm), and the first electron injection layer 7 (LiF, 1nm). The evaporation rate is controlled at 0.1-5Å / s.

[0044] S4. Preparation of intermediate electrode layer: Maintaining a vacuum environment, vacuum thermally evaporates an Ag layer (10nm, 5Å / s), and then deposits an ITO layer (50nm, 1Å / s) using an electron beam evaporation process. After photolithography and etching patterning, electrical connection with the CMOS driving circuit is achieved to form intermediate electrode layer 8.

[0045] S5. Fabrication of the second light-emitting unit: Maintaining a vacuum environment, a vacuum thermal evaporation process was used to sequentially deposit the second hole injection layer 9 (PEDOT:PSS, 20nm), the second hole transport layer 10 (NPB, 40nm), the second red light emitting layer 11 (Alq3:DCJTB, 30nm), the second electron transport layer 12 (TPBi, 30nm), and the second electron injection layer 13 (LiF, 1nm). The evaporation rate was controlled at 0.1-5 Å / s.

[0046] S6. Cathode Layer and Packaging Fabrication: A Mg:Ag alloy layer (20nm, 8Å / s) is vacuum thermally deposited to form the cathode layer 14; a SiNx layer is prepared by plasma-enhanced chemical vapor deposition (PECVD), and a polyimide layer is prepared by inkjet printing to form an inorganic / organic composite packaging layer 15; finally, the cover glass 16 is bonded with UV-cured optical adhesive to complete the device fabrication.

[0047] This embodiment and Figure 1 Comparison test results of conventional solutions with the same pixel density: The device in this embodiment can achieve stable switching between three modes: blue light, red light, and red-blue mixed light, without the color difference problem caused by color filter. The comparison results of the core performance indicators are shown in Table 1 below:

[0048] Core performance indicators This invention relates to a 4000 PPI red-blue dual-color OLED device. Figure 1 Conventional stacked OLED devices with the same pixel density + color filter Performance change magnitude (improvement / decrease) Pixel aperture ratio 66.3% 25% An increase of 165.2% Drive voltage 5.44V 8.0V 32% reduction Optical loss 27% 60% Reduce by 55% Device effective lifespan 8250h 5000h Increase by 65% Power consumption at standard brightness 90mW 150mW Reduced by 40%

[0049] Example 2: 3500PPI Yellow-Green Dual-Color Switching OLED Device

[0050] An OLED device structure capable of layered color switching differs from Embodiment 1 in that:

[0051] The CMOS driving circuit of the single-crystal silicon substrate 1 has a pixel density of 3500 PPI, which is suitable for mid-to-high-end AR / VR near-eye displays;

[0052] The first luminescent layer 5 is a green luminescent layer (Alq3, 30nm), and the second luminescent layer 11 is a yellow luminescent layer (YAG:Ce³+, 30nm).

[0053] The intermediate electrode layer 8 is a composite structure of Al layer (8nm) + IZO layer (40nm);

[0054] Anode layer 2 is an Ag-based composite anode (80nm), and cathode layer 14 is an ultrathin Ag layer (15nm).

[0055] The encapsulation layer 15 is an inorganic / organic alternating stacked structure of SiO2 (150nm) + acrylate (3μm) + SiO2 (150nm), with a water and oxygen permeability of 3×10^-7g / (m²・day).

[0056] The preparation method is basically the same as that in Example 1, except that the vapor deposition material and film thickness are adjusted according to the above differences.

[0057] This embodiment and Figure 1 Comparison test results of conventional solutions with the same pixel density: The device in this embodiment can achieve three-mode switching of green light, yellow light, and yellow-green mixed light, and the light color uniformity is better than that of conventional solutions. The comparison results of the core performance indicators are shown in Table 2 below:

[0058] Core performance indicators This invention relates to a 3500 PPI yellow-green dual-color OLED device. Figure 1 Conventional stacked OLED devices with the same pixel density + color filter Performance change magnitude (improvement / decrease) Pixel aperture ratio 66.2% 28% An increase of 136.4% Drive voltage 5.25V 7.5V Reduced by 30% Optical loss 27.8% 58% Reduced by 52% Device effective lifespan 8360h 5500h Increased by 52% Power consumption at standard brightness 78mW 130mW Reduced by 40%

[0059] Example 3: 3000PPI Blue-Green Dual-Color Switching OLED Device

[0060] An OLED device structure capable of layered color switching differs from Embodiment 1 in that:

[0061] The CMOS driving circuit of the single-crystal silicon substrate 1 has a pixel density of 3000 PPI, which is suitable for entry-level AR / VR near-eye displays;

[0062] The first light-emitting layer 5 is a blue light-emitting layer (DPVBi, 30nm), and the second light-emitting layer 11 is a green light-emitting layer (Alq3, 30nm).

[0063] The intermediate electrode layer 8 is a composite structure of Mg:Ag alloy layer (15nm) + ITO layer (80nm);

[0064] The anode layer 2 is an ITO / Ag / ITO stacked structure (150nm), and the cathode layer 14 is an ITO / Ag / ITO composite cathode (30nm).

[0065] The encapsulation layer 15 is an inorganic / organic alternating stacked structure of Al2O3 (200nm) + polyimide (8μm) + Al2O3 (200nm), with a water and oxygen permeability of 8×10^-7g / (m²・day).

[0066] Its preparation method is completely consistent with that of Example 1.

[0067] This embodiment and Figure 1 Comparison test results of conventional solutions with the same pixel density: The device in this embodiment can achieve stable switching between three modes: blue light, green light, and blue-green mixed light. The fabrication yield is higher than that of conventional solutions. The comparison results of the core performance indicators are shown in Table 3 below:

[0068] Core performance indicators This invention relates to a 3000 PPI blue-green dual-color OLED device. Figure 1 Conventional stacked OLED devices with the same pixel density + color filter Performance change magnitude (improvement / decrease) Pixel aperture ratio 66% 30% 120% increase Drive voltage 5.04V 7.0V 28% reduction Optical loss 24.75% 55% Reduce by 55% Device effective lifespan 8400h 6000h Increase by 40% Power consumption at standard brightness 66mW 110mW Reduced by 40%

[0069] This invention abandons the color filter structure and achieves color switching without a color filter by switching electrode polarity. This significantly improves pixel aperture ratio, reduces driving voltage by over 28%, and lowers power consumption by 40% at standard brightness. It fundamentally reduces optical losses by over 50%, breaking the vicious cycle of brightness compensation, increasing device lifespan by over 40%, and greatly improving core optoelectronic performance and operational stability. Simultaneously, by utilizing a CMOS driving circuit, it can achieve three-mode switching: independent illumination of two monochromatic lights and cascaded illumination of mixed colors. This solves the problem of fixed light colors in conventional solutions, and the composite electrode layer further ensures the stability of light color switching, avoiding color difference issues caused by color filters.

[0070] Furthermore, this invention eliminates the complex process of color filter fabrication, is fully compatible with existing OLED industrialization processes, requires no additional specialized equipment, significantly improves fabrication yield, and substantially reduces industrialization costs and process complexity. The device structure is adapted to ultra-high pixel densities of ≥3000 PPI, flexibly matching high, medium, and low-end AR / VR near-eye display scenarios, making it highly practical.

[0071] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art or related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A layered, color-switching OLED device structure, comprising a silicon substrate, an anode layer, a cathode layer, an organic functional layer, an encapsulation layer, and a cover glass, wherein a CMOS driving circuit is integrated on the surface of the silicon substrate, and the anode layer, organic functional layer, cathode layer, encapsulation layer, and cover glass are sequentially stacked along the light emission direction of the silicon substrate, characterized in that... The organic functional layer includes a first light-emitting unit, an intermediate electrode layer, and a second light-emitting unit stacked sequentially along the light-emitting direction. The first light-emitting unit is disposed between the anode layer and the intermediate electrode layer, and the second light-emitting unit is disposed between the intermediate electrode layer and the cathode layer. The first light-emitting unit and the second light-emitting unit are respectively provided with light-emitting layers that emit light with different peak wavelengths. The intermediate electrode layer is a conductive layer structure composed of metal and transparent conductive oxide. The anode layer, the intermediate electrode layer, and the cathode layer are all electrically connected to the CMOS driving circuit. The intermediate electrode layer can switch the power supply polarity to work as an anode or a cathode through the CMOS driving circuit. By controlling the power supply state of the anode layer, the intermediate electrode layer, and the cathode layer, the first light-emitting unit or the second light-emitting unit can be selectively lit to achieve layered switching of the light color emitted by the device.

2. The OLED device structure with layered color switching according to claim 1, characterized in that, The first light-emitting unit includes a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, and a first electron injection layer stacked sequentially along the light emission direction; the second light-emitting unit includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and a second electron injection layer stacked sequentially along the light emission direction.

3. The OLED device structure with layered color switching according to claim 1, characterized in that, The first and second light-emitting layers emit light of any two different colors from red, green, blue, yellow, and white; the first and second light-emitting units can be lit simultaneously to achieve mixed light emission of the two colors.

4. The OLED device structure with layered color switching according to claim 1, characterized in that, The metal layer of the intermediate electrode layer is selected from any one of Ag layer, Al layer, and Mg:Ag alloy layer, with a thickness of 5nm-30nm; the transparent conductive oxide layer is selected from any one of ITO layer and IZO layer, with a thickness of 10nm-100nm; the metal layer is disposed on the side closer to the first light-emitting unit, and the transparent conductive oxide layer is disposed on the side closer to the second light-emitting unit.

5. The OLED device structure with layered color switching according to claim 1, characterized in that, The anode layer is a high-reflectivity composite anode, selected from any one of ITO / Ag / ITO stacked structure and Ag-based composite anode, with a total thickness of 50nm-200nm; the cathode layer is a semi-transparent conductive cathode, selected from any one of Mg:Ag alloy layer, ultrathin Ag layer, and ITO / Ag / ITO composite cathode, with a thickness of 5nm-50nm.

6. The OLED device structure with layered color switching according to claim 1, characterized in that, The CMOS driving circuit controls the light color switching of the device in three modes: Mode 1, the intermediate electrode layer is configured as a cathode, a positive driving voltage is applied to the anode layer, the cathode layer is suspended, only the first light-emitting unit is lit, and the device emits the first light color; Mode 2, the intermediate electrode layer is configured as an anode, a negative driving voltage is applied to the cathode layer, the anode layer is suspended, only the second light-emitting unit is lit, and the device emits the second light color; Mode 3, a positive driving voltage is applied to the anode layer, a negative driving voltage is applied to the cathode layer, the intermediate electrode layer is suspended, the first light-emitting unit and the second light-emitting unit are lit in series, and the device emits a mixed light color.

7. The OLED device structure with layered color switching according to claim 1, characterized in that, The silicon substrate is a single-crystal silicon substrate, and the pixel density of the CMOS driving circuit integrated on its surface is ≥3000PPI.

8. The OLED device structure with layered color switching according to claim 1, characterized in that, The encapsulation layer is a composite thin-film encapsulation structure with alternating inorganic and organic layers, comprising at least two inorganic barrier layers and at least one organic planarization layer; the inorganic barrier layer is selected from any one of SiNx, SiO2, and Al2O3, with a single layer thickness of 50nm-500nm; the organic planarization layer is selected from acrylate or polyimide materials, with a single layer thickness of 1μm-10μm; the water and oxygen permeability of the encapsulation layer is ≤1×10^-6g / (m²・day).

9. A method for fabricating an OLED device structure capable of layered color switching, characterized in that, The method for preparing the OLED device structure with layered color switching as described in any one of claims 1-8 includes the following steps: S1 Substrate Pretreatment: Select a single-crystal silicon substrate with CMOS driving circuit integrated on its surface, and perform ultrasonic cleaning with organic solvent, rinsing with deionized water, drying with nitrogen gas in sequence, and then oxygen plasma activation treatment to complete the substrate pretreatment. S2 Anode Layer Preparation: A conductive anode film is deposited on the pretreated substrate surface using physical vapor deposition. The patterning is completed by photolithography, development, and etching processes to form an anode layer that is electrically connected to the CMOS driving circuit. S3 First Light-Emitting Unit Preparation: In a vacuum chamber with a vacuum degree ≤5×10^-4Pa, a vacuum thermal evaporation process is used to sequentially prepare the first hole injection layer, the first hole transport layer, the first light-emitting layer, the first electron transport layer and the first electron injection layer on the surface of the anode layer to complete the preparation of the first light-emitting unit; S4 intermediate electrode layer fabrication: Maintaining a vacuum environment, a metal conductive layer is prepared using a vacuum thermal evaporation process, and then a transparent conductive oxide layer is prepared using an electron beam evaporation process to form an intermediate electrode layer. Electrical connection with the CMOS driving circuit is achieved through a patterning process. S5 Second Light-Emitting Unit Fabrication: Maintaining a vacuum environment, a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and a second electron injection layer are sequentially fabricated on the surface of the intermediate electrode layer using a vacuum thermal evaporation process to complete the fabrication of the second light-emitting unit; S6 Cathode Layer and Packaging Fabrication: The cathode layer is prepared using a vacuum thermal evaporation process, followed by an inorganic / organic composite packaging layer prepared using chemical vapor deposition and inkjet printing processes. Finally, the cover glass is bonded to complete the device fabrication.

Images