A full-phosphorescent white light OLED device and a preparation method thereof

Abstract

The application provides a full-phosphorescence white light OLED device and a preparation method thereof, and belongs to the technical field of semiconductor devices.The full-phosphorescence white light OLED device provided by the application comprises a full-phosphorescence single light-emitting layer, the full-phosphorescence single light-emitting layer comprises a host material and a phosphorescence guest doping material, and the phosphorescence guest doping material comprises red phosphorescence guest material, green phosphorescence guest material and blue phosphorescence guest material.The full-phosphorescence single light-emitting layer of the application is completely free of fluorescent material and thermally activated delayed fluorescence, so as to realize white light emission covering the visible spectrum.Because there is only a single light-emitting layer, the exciton recombination region is strictly limited in the physical layer and does not move in space with the change of driving current density, the full-phosphorescence system has an internal quantum efficiency close to 100%, high brightness output can be realized at a lower current density, full gray scale high color stability is realized, and the problem of large color coordinate deviation in the high and low gray scale ranges of traditional OLED devices is solved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to an all-phosphorescent white OLED device and its fabrication method. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have been widely used in high-end display fields due to their advantages such as self-emission, high contrast, and wide viewing angle. In related technologies, to achieve high-efficiency white light or color emission, a multi-emitting-layer structure combining fluorescent and phosphorescent materials is often employed, such as... Figure 1 As shown, for example, a hybrid white light system can be constructed using blue fluorescent materials and red / green phosphorescent materials. This system includes a substrate, an anode, a hole injection layer (HIL), a hole transport layer (HTL), a blue fluorescent layer (EML-1), an intermediate layer (INT), a yellow / red-green phosphorescent layer (EML-2), an electron transport layer (ETL), an electron injection layer (EIL), a cathode, and a sealing layer, stacked sequentially. However, this type of structure suffers from significant high and low grayscale color coordinate shifts in practical applications, severely affecting display color accuracy and visual consistency.

[0003] There are two main reasons for this problem: Firstly, in high-resolution display panels, in order to improve the aperture ratio or simplify the process, some areas may not have a pixel definition layer (PDL) or the PDL coverage may be incomplete, which causes lateral leakage of charge carriers at the pixel edges, causing the current density distribution of the effective light-emitting area to change with the gray level, thereby causing the emission spectrum to shift. Secondly, blue light devices based on fluorescence mechanisms are limited by the utilization rate of singlet excitons (theoretically up to 25%). Their external quantum efficiency (EQE) usually shows a trend of first increasing and then decreasing with the increase of driving current density. In contrast, red / green phosphorescent devices can achieve maximum EQE at extremely low current densities by fully utilizing triplet excitons. This significant difference in efficiency-current response characteristics leads to a relatively insufficient luminous intensity of the blue light component under low brightness (low grayscale) operating conditions, while the red and green light components dominate. This results in an imbalance in the energy distribution of the white light spectrum, with the CIE color coordinates shifting towards the yellow / red direction, resulting in a color drift phenomenon of "low brightness yellowish".

[0004] While existing technologies have attempted to alleviate these problems by optimizing carrier transport layer energy levels, introducing recombination region modulation layers, or strengthening the PDL structure, these solutions often increase device complexity, sacrifice efficiency, or struggle to achieve stable color coordinate control across the entire grayscale range. Therefore, a novel OLED device architecture with a simple structure and excellent color stability is urgently needed. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a full phosphorescent white OLED device and its fabrication method. The full phosphorescent white OLED device provided by this invention solves the problem of large color coordinate shifts in the high and low grayscale ranges of traditional OLED devices through host-guest energy level synergistic design.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a full phosphorescent white OLED device, comprising an anode, a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a full phosphorescent single emitting layer (EML), a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL), a cathode, and a sealing layer (encapsulation layer, TFE) stacked sequentially. The all-phosphorescent single-emitting layer includes a host material and a phosphorescent guest doping material, wherein the phosphorescent guest doping material includes red phosphorescent guest material (RD), green phosphorescent guest material (GD), and blue phosphorescent guest material (BD).

[0007] Preferably, the triplet energy level (T1, Host) of the host material is greater than that of the blue phosphorescent guest material (T1, BD), which is greater than that of the green phosphorescent guest material (T1, GD), which is greater than that of the red phosphorescent guest material (T1, RD).

[0008] Preferably, the HOMO energy level of the host material is higher than that of the red phosphorescent guest material, and the LUMO energy level is lower than that of the blue phosphorescent guest material.

[0009] Preferably, the doping concentration of the blue phosphorescent guest material is 1.5wt%~7wt%; the doping concentration of the red phosphorescent guest material is 0.25wt%~2wt%; and the doping concentration of the green phosphorescent guest material is 0.5wt%~2.5wt%.

[0010] Preferably, the doping concentration of the blue phosphorescent guest material is 6 wt%; the doping concentration of the red phosphorescent guest material is 1.5 wt%; and the doping concentration of the green phosphorescent guest material is 1 wt%.

[0011] Preferably, the phosphorescent guest doping material has ≥3 types.

[0012] Preferably, the thickness of the all-phosphorescent single-emitting layer is 20~40nm.

[0013] Preferably, the thickness of the phosphorescent single-emitting layer is 25~30nm.

[0014] Preferably, the hole blocking layer has a thickness of 8-15 nm, and the electron blocking layer has a thickness of 5-15 nm.

[0015] This invention also provides a method for fabricating the all-phosphorescent white OLED device described above, comprising the following steps: An anode, a hole injection layer, a hole transport layer, an electron blocking layer, a full phosphorescent single-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and a sealing layer are sequentially deposited on the surface of a substrate to obtain the full phosphorescent white OLED device.

[0016] This invention provides a fully phosphorescent white OLED device, comprising an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a fully phosphorescent single-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and a sealing layer, which are stacked sequentially. The fully phosphorescent single-emitting layer comprises a host material and a phosphorescent guest dopant material, wherein the phosphorescent guest dopant material comprises a red phosphorescent guest material, a green phosphorescent guest material, and a blue phosphorescent guest material.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The all-phosphorescent single-emitting layer of the present invention contains no fluorescent materials or thermally activated delayed fluorescence (TADF). Instead, it is composed of phosphorescent guest doping materials (including three or more phosphorescent materials with different emission wavelengths) co-doped in the same host material, including at least red phosphorescent guest materials, green phosphorescent guest materials and blue phosphorescent guest materials, so as to achieve white light emission covering the visible spectrum. Because there is only a single emitting layer, the exciton recombination region is strictly confined within this physical layer and does not spatially shift with changes in driving current density. At the same time, the all-phosphorescent system has an internal quantum efficiency of nearly 100%, which can achieve high brightness output at low current density. Therefore, even in pixel areas without a pixel definition layer, the influence of lateral leakage current on luminous uniformity is effectively suppressed, and the device can still maintain stable color and brightness distribution. This is beneficial for simplifying the manufacturing process, increasing aperture ratio, achieving high color stability across the entire grayscale, and solving the problem of large color coordinate shifts in the high and low grayscale range of traditional OLED devices. If only two phosphorescent guest doping materials are used (such as blue + orange, blue + yellow, red + green), "visual white light" can be produced, but it cannot cover the entire visible spectrum (especially lacking green or red light). The color coordinates will deviate significantly from the standard white point (such as D65). Only the combination of red, green, and blue (RGB) three primary colors can construct high-quality white light with continuous spectrum, wide color gamut, and controllable color temperature, meeting the color consistency requirements of high-end applications such as AMOLED displays.

[0018] Furthermore, the all-phosphorescent single-emitting layer of the present invention is based on a host-guest energy level synergistic design. The triplet energy level (T1, Host) of the host material is higher than that of all phosphorescent guest doped materials, satisfying: T1, Host > T1, blue light (BD) > T1, green light (GD) > T1, red light (RD). At the same time, the HOMO energy level of the host material is higher than that of the red phosphorescent guest material and the LUMO energy level is lower than that of the blue phosphorescent guest material, so as to promote the preferential capture of holes and electrons by red and blue guests respectively. This energy level gradient ensures that excitons are rapidly and directionally transferred to the target guest and radiatively recombine after being generated on the host, effectively suppressing exciton diffusion, energy backhaul or cross-color Förster resonance energy transfer (FRET), and ensuring the stability of the emission ratio of each color component from the source.

[0019] Furthermore, this invention designs a doping concentration gradient compensation for the three-color start-up threshold. Addressing the issue of asynchronous start-up voltages caused by bandgap differences in different phosphorescent guest doped materials, based on the physical mechanism that "higher doping concentration leads to a greater carrier capture probability and a lower start-up voltage," an asymmetric doping concentration design is implemented for the three-color phosphorescent guest doped materials. Blue phosphorescent guest materials (BD): Increase the doping concentration (1.5wt%~7wt%) to compensate for the hysteresis caused by its high bandgap; Red phosphorescent guest materials (RD): Appropriately reduce the doping concentration (0.25wt%~2wt%) to suppress premature turn-on due to narrow bandgap; Green phosphorescent guest materials (GD): with a moderate doping concentration (0.5wt%~2.5wt%), they serve as both a spectral transition and a bridge in the energy transfer chain; This strategy enables tri-color emission at 1 cd / m² 2 The start-up voltage deviation at the specified brightness is ≤0.3V, which significantly improves the consistency of low grayscale color coordinates.

[0020] Furthermore, the thickness of the all-phosphorescent single-emitting layer in this invention is controlled at 20~40nm. Combining the bidirectional carrier confinement effect of EBL and HBL, and taking advantage of the characteristics of long triplet exciton lifetime (on the order of μs) and easy interface quenching of all-phosphorescent materials, performance is maximized. This thickness range has the following advantages: (i) Ensure that the exciton recombination region is stably located in the central region of the luminescent layer: with a thickness range of 20~40nm, combined with the bidirectional effects of EBL (blocking electron diffusion to HTL) and HBL (blocking hole leakage to ETL), the exciton recombination region can be firmly locked in the central region of EML, so that the recombination region maintains a sufficient distance from the HTL / EML and EML / HBL interfaces, effectively avoiding the nonradiative recombination, exciton quenching and energy backhaul problems of triplet excitons at the interface in the whole phosphorescence system, and improving exciton utilization.

[0021] (ii) A thickness of 20~40nm can maintain sufficient luminescence intensity while avoiding the problem that the composite region is susceptible to voltage fluctuations due to excessively thin thickness (<20nm) and uneven electric field distribution caused by excessively thick thickness (>40nm), thus significantly reducing the color drift of the device and improving the color stability of the entire grayscale.

[0022] The present invention also provides a method for fabricating the all-phosphorescent white OLED device described above. The fabrication method of the present invention is simple to operate and suitable for industrial application. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an OLED device in related technologies; Figure 2 This is a schematic diagram of the structure of the all-phosphorescent white OLED device in Embodiment 1 of the present invention. Detailed Implementation

[0024] This invention provides a full phosphorescent white OLED device, comprising an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a full phosphorescent single emitting layer (single phosphorescent emitting layer), a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and a sealing layer, which are stacked sequentially. The all-phosphorescent single-emitting layer includes a host material and a phosphorescent guest doping material, wherein the phosphorescent guest doping material includes red phosphorescent guest material, green phosphorescent guest material and blue phosphorescent guest material.

[0025] Unless otherwise specified, all raw materials and equipment used in this invention are commercially available products in the field.

[0026] In this invention, the all-phosphorescent white OLED device preferably also includes a substrate. This invention does not have a special limitation on the specific type of substrate, and any type known to those skilled in the art can be used, such as a silicon-based CMOS backplane.

[0027] In this invention, the anode is preferably made of a metal, a metal nitride, or a transparent metal oxide. The metal is preferably Ti or Al, and the metal nitride is preferably TiN. x The transparent metal oxide is preferably indium tin oxide (ITO).

[0028] In this invention, the thickness of the anode is preferably 100 nm, and the surface roughness is preferably <1 nm.

[0029] In this invention, the thickness of the hole injection layer is preferably 5~15nm, specifically 5, 10 or 15nm.

[0030] In this invention, the hole injection layer is preferably: (i) Monolayer p-type organic semiconductor materials, such as hexacyanohexaazabenzophenanthrene (HAT-CN) or molybdenum trioxide (MoO3). (ii) A p-type doped system, which is formed by co-doping a hole transport matrix and a p-type dopant, wherein the p-type dopant accounts for 1 to 10% of the mass percentage of the hole transport matrix; the hole transport matrix may be TAPC, NPB or TCTA, and the p-type dopant may be F4-TCNQ, HAT-CN or NDP-9.

[0031] In this invention, the thickness of the hole transport layer is preferably 30~60nm, specifically 30, 40, 50 or 60nm.

[0032] In this invention, the hole transport layer is preferably made of a hole transport material with a high triplet energy level (T1≥2.8eV), such as TAPC, TCTA or NPB.

[0033] In this invention, the thickness of the electron blocking layer is preferably 5~15nm.

[0034] In this invention, the electron blocking layer is preferably made of an organic material with a triplet energy level higher than that of the blue phosphorescent guest, such as TCTA (4,4',4''-tris(carbazole-9-yl)triphenylamine) or mCP, which blocks electron diffusion to the HTL and adapts to the hole transport channel to ensure efficient hole injection into the EML and suppress exciton interface quenching.

[0035] In this invention, the preferred triplet energy level is: triplet energy level of the host material > triplet energy level of the blue phosphorescent guest material > triplet energy level of the green phosphorescent guest material > triplet energy level of the red phosphorescent guest material.

[0036] In this invention, the HOMO energy level of the host material is preferably higher than that of the red phosphorescent guest material, and the LUMO energy level is preferably lower than that of the blue phosphorescent guest material.

[0037] This invention promotes the preferential capture of holes and electrons by red and blue light guests, respectively, through a host-guest energy level synergistic design. The energy level gradient ensures that excitons are rapidly and directionally transferred to the target guest and radiatively recombine after being generated on the host. This effectively suppresses exciton diffusion, energy backhaul, or cross-color Förster resonance energy transfer, thus ensuring the stability of the luminescence ratio of each color component from the source.

[0038] This invention designs a doping concentration gradient compensation for the three-color start-up threshold. To address the asynchronous start-up voltage problem caused by bandgap differences in different phosphorescent guest doped materials, based on the physical mechanism that "the higher the doping concentration, the greater the carrier capture probability and the lower the start-up voltage", an asymmetric doping concentration design is implemented for the three-color phosphorescent guest doped materials. The design is carried out independently according to the physical characteristics of each phosphorescent guest doped material (including start-up voltage, capture cross section, luminous efficiency, and energy transfer path).

[0039] In this invention, the doping concentration of the blue phosphorescent guest material is preferably 1.5wt% to 7wt%, specifically 6wt%; the doping concentration of the red phosphorescent guest material is preferably 0.25wt% to 2wt%, specifically 1.5wt%; and the doping concentration of the green phosphorescent guest material is preferably 0.5wt% to 2.5wt%, specifically 1wt%. The doping concentration refers to the percentage by mass of the phosphorescent guest dopant material relative to the main material.

[0040] In this invention, the phosphorescent guest doping material is preferably of ≥3 types, consisting of three or more phosphorescent guest doping materials with different emission wavelengths co-doped in the same host material, including at least red, green and blue phosphorescent guest materials, to achieve white light emission covering the visible spectrum.

[0041] The present invention does not specifically limit the type of phosphorescent guest material. Red, green and blue phosphorescent guest materials well known to those skilled in the art can be used. Specifically, blue phosphorescent guest material is Firpic, green phosphorescent guest material is Ir(ppy)3, and red phosphorescent guest material is Ir(pq)2(acac).

[0042] In this invention, the main material preferably includes one or more of mCP (1,3-dicarbazole-9-ylphenyl), CBP (4,4'-di(9-carbazole)biphenyl), TCTA (tris(4-carbazole-9-ylphenyl)amine), and Bepp2 (di(2-hydroxyphenylpyridine)beryllium).

[0043] In this invention, the full phosphorescent single-emitting layer preferably further includes auxiliary phosphorescent materials, more preferably including one or more of deep blue phosphorescent materials, yellow phosphorescent materials, orange phosphorescent materials, narrow-spectrum red phosphorescent materials and near-infrared phosphorescent materials, wherein the narrow-spectrum red phosphorescent materials and near-infrared phosphorescent materials are used to adjust the color temperature, improve the color gamut or enhance the color rendering.

[0044] In this invention, the thickness of the full phosphorescent single emitting layer is preferably 20~40nm, more preferably 25~30nm. This thickness range, combined with the bidirectional carrier confinement effect of EBL and HBL, can stably lock the exciton recombination region at the center of the emitting layer, away from the interface quenching region, effectively avoiding nonradiative loss of triplet excitons, and suppressing recombination region drift caused by excessively thin (<20nm) or excessively thick (>40nm) thickness, significantly improving the stability of the full grayscale color.

[0045] In this invention, the thickness of the hole blocking layer is preferably 8~15nm, specifically 8, 10, 13 or 15nm, to block holes from leaking into the ETL, retain electrons in the EML, optimize the carrier recombination region, and improve color stability.

[0046] In this invention, the hole blocking layer is preferably made of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline).

[0047] In this invention, the thickness of the electron transport layer is preferably 30~60nm, specifically 30, 35, 45, 50, 55 or 60nm, and the material preferably includes TmPyPB (1,3,5-tris[(3-pyridyl)-3-phenyl]benzene) or a mixture of TmPyPB and LiQ (8-hydroxyquinoline lithium), wherein the mass ratio of TmPyPB to LiQ in the mixture is preferably 4:6.

[0048] In this invention, the thickness of the electron injection layer is 0.5~2 nm, specifically 0.5, 1, 1.5, 2 or 2 nm, and the material is preferably a low work function compound, such as LiF, CsF or Cs2CO3. In a specific embodiment of this invention, the electron injection layer is LiF with a thickness of 1 nm.

[0049] In this invention, the thickness of the cathode is preferably 10-20 nm, specifically 10, 13, 15, 18, or 20 nm. The cathode serves as the top-emitting light port, and its material is preferably a semi-transparent metal alloy. In a specific embodiment of this invention, the cathode is a Mg:Ag alloy (Mg:Ag mass ratio 1:9) with a thickness of 15 nm.

[0050] In this invention, the encapsulation layer is preferably composed of alternately stacked SiN x Composed of Al2O3, the SiN x Preferably, it is disposed on the surface of the cathode.

[0051] In this invention, the thickness of the encapsulation layer is preferably 500~1000nm, specifically 500, 800 or 1000nm.

[0052] In this invention, the encapsulation layer preferably has high water and oxygen barrier properties, and the water and oxygen permeability is preferably ≤10. -6 g / (m 2 ·day).

[0053] This invention also provides a method for fabricating the all-phosphorescent white OLED device described above, comprising the following steps: An anode, a hole injection layer, a hole transport layer, an electron blocking layer, a full phosphorescent single-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and a sealing layer are sequentially deposited on the surface of a substrate to obtain the full phosphorescent white OLED device.

[0054] The present invention does not impose any particular limitation on the deposition method, and chemical vapor deposition or evaporation methods well known to those skilled in the art can be used.

[0055] The advantages of the all-phosphorescent white OLED device provided by this invention are as follows: 1. Eliminate recombination region shift: The all-phosphorescent single-emitting-layer structure fixes the exciton recombination region, fundamentally solving the spectral drift problem; 2. Multi-dimensional synergistic optimization: High color stability across the entire grayscale is achieved through energy level matching, doping ratio optimization, and full phosphorescence single-emitting layer thickness optimization; 3. Reduced dependence on PDL: The high efficiency of full phosphorescence weakens the impact of lateral leakage current, supporting PDL-free designs; 4. Simplified structure and high yield: No complex multi-layer light-emitting structure is required, it is compatible with existing evaporation processes, and it is conducive to mass production; 5. Improved efficiency: Compared with traditional phosphorescent + fluorescent devices, this invention can improve the luminous efficiency of the device by 50%.

[0056] The present invention also provides the all-phosphorescent white OLED device described above for use in AR / VR and near-eye display high-resolution application scenarios.

[0057] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0058] Example 1 A fully phosphorescent white OLED device, Figure 2 This is a schematic diagram of the structure of the all-phosphorescent white OLED device in Example 1, which is directly integrated on the CMOS driver backplane. The device, from bottom to top (from the silicon substrate side to the light-emitting side), includes: Silicon-based CMOS backplane: includes pixel driving transistors, planarization layer (SiO2), tungsten plug vias, and surface-fabricated metal electrodes (Ti, 100nm thickness, surface roughness <1nm); this device does not have a pixel definition layer. Hole injection layer: TAPC: NDP-9 (NDP-9 doping concentration is 3%, doping concentration refers to the mass percentage of NDP-9 in TAPC), thickness 10nm; Hole transport layer: TAPC, 30nm thick; Electron blocking layer: TCTA, 5nm thick; All-phosphorescent single-emitting layer: 25nm thick, composed of host material mCP and three phosphorescent guest materials co-doped, with specific doping concentrations as follows: FIRPIC, a blue phosphorescent guest material: 6.0 wt%. Green phosphorescent guest material Ir(ppy)3: 1.5wt%, Red phosphorescent guest material Ir(pq)2(acac): 1.0 wt% Doping concentration refers to the mass percentage of the phosphorescent guest doped material relative to the host material. Hole blocking layer: BCP, 8nm thick; Electron transport layer: TmPyPB:LiQ (TmPyPB to LiQ mass ratio 4:6), thickness 35nm; Electron injection layer: LiF, 1 nm thick; Semi-transparent cathode: Mg:Ag (Mg to Ag mass ratio 1:9), thickness 15nm; Encapsulation layer: composed of alternating stacked SiN x Composed of Al2O3, SiN x Located on the surface of the cathode, with a thickness of 800 nm, and a water-oxygen permeability ≤10. -6 g / (m 2 ·day).

[0059] Preparation method: An anode, hole injection layer, hole transport layer, electron blocking layer, full phosphorescent single-emitting layer, hole blocking layer, electron transport layer, electron injection layer, cathode and encapsulation layer are sequentially deposited on the surface of a silicon-based CMOS backplane to obtain the full phosphorescent white OLED device.

[0060] Performance Tests and Results At 100cd / m 2 At this brightness, the CIE 1931 color coordinates are (0.316, 0.334), which closely match the D65 white point. 1~1000cd / m 2 Within the brightness range, the color coordinates change as follows: 1cd / m 2 : (0.338, 0.336); 100cd / m 2 : (0.316, 0.334); 1000cd / m 2 (0.309, 0.333); Maximum color deviation Δxy < 0.03; Turn-on voltage (1 cd / m 2 ): 3.2V.

[0061] Comparative Example have Figure 2 The OLED device with the structure shown is directly integrated onto the CMOS driver backplane. The device, from bottom to top (from the silicon substrate side to the light-emitting side), includes: Silicon-based CMOS backplane: includes pixel driving transistors, planarization layer (SiO2), tungsten plug vias, and surface-fabricated metal electrodes (Ti, 100nm thickness, surface roughness <1nm); this device does not have a pixel definition layer. Hole injection layer: TAPC: NDP-9 (NDP-9 doping concentration is 3%, doping concentration refers to the mass percentage of NDP-9 in TAPC), thickness 10nm; Hole transport layer: TAPC, 40nm thick; Blue phosphor layer: mCP+DPVBi, where the doping concentration of DPVBi is 10% of the mass percentage of mCP, and the thickness is 25nm; Intermediate layer: BCP, 15nm thick; Yellow / red-green phosphorescent layer: CBP + Ir(ppy)3 + Ir(pq)2(acac), where the doping concentration of Ir(ppy)3 is 8% of the mass percentage of CBP and the doping concentration of Ir(pq)2(acac)2 is 2% of the mass percentage of CBP, with a thickness of 20nm. Electron transport layer: TmPyPB:LiQ (TmPyPB to LiQ mass ratio 4:6), thickness 40nm; Electron injection layer: LiF, 1 nm thick; Semi-transparent cathode: Mg:Ag (Mg to Ag mass ratio 1:9), thickness 15nm; Encapsulation layer: composed of alternating stacked SiN x Composed of Al2O3, SiN x Located on the surface of the cathode, with a thickness of 800 nm, and a water-oxygen permeability ≤10. -6 g / (m 2 ·day).

[0062] Preparation method: An OLED device is obtained by depositing an anode, a hole injection layer, a hole transport layer, a blue phosphor layer, an intermediate layer, a yellow / red-green phosphor layer, an electron transport layer, an electron injection layer, a semi-transparent cathode, and an encapsulation layer on the surface of a silicon-based CMOS backplane.

[0063] The performance test results of the OLED devices in Example 1 and the comparative example are shown in Table 1. It can be seen that the OLED device provided by this invention is a full phosphorescent white OLED device containing only a single emissive layer. Through host-guest energy level synergistic design, doping ratio optimization, and emissive layer thickness optimization, it solves the problem of large color coordinate shifts in the high and low grayscale ranges of traditional silicon-based OLED devices, eliminating recombination region movement. The full phosphorescent single emissive layer structure fixes the exciton recombination region, fundamentally solving spectral drift. It features multi-dimensional synergistic optimization, achieving high color stability across the entire grayscale range through energy level matching, doping ratio optimization, and full phosphorescent single emissive layer thickness optimization. It reduces dependence on PDL, and the high efficiency characteristics of full phosphorescence weaken the influence of lateral leakage current, supporting PDL-free design. It has a simplified structure, high yield, eliminates the need for complex multi-layer emissive structures, is compatible with existing evaporation processes, and facilitates mass production. Efficiency is improved; compared to traditional phosphorescent + fluorescent devices, this invention can improve device luminous efficiency by 50%.

[0064] Table 1 Performance test results of the OLED devices in Example 1 and the comparative example

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A fully phosphorescent white OLED device, characterized in that, It includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a full phosphorescent single-emission layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and a sealing layer, which are stacked in sequence. The all-phosphorescent single-emitting layer includes a host material and a phosphorescent guest doping material, wherein the phosphorescent guest doping material includes red phosphorescent guest material, green phosphorescent guest material and blue phosphorescent guest material.

2. The all-phosphorescent white OLED device according to claim 1, characterized in that, The triplet energy level of the host material is greater than that of the blue phosphorescent guest material, which is greater than that of the green phosphorescent guest material, which is greater than that of the red phosphorescent guest material.

3. The all-phosphorescent white OLED device according to claim 1 or 2, characterized in that, The HOMO energy level of the host material is higher than that of the red phosphorescent guest material, and the LUMO energy level is lower than that of the blue phosphorescent guest material.

4. The all-phosphorescent white OLED device according to claim 1, characterized in that, The doping concentration of the blue phosphorescent guest material is 1.5wt%~7wt%; the doping concentration of the red phosphorescent guest material is 0.25wt%~2wt%; and the doping concentration of the green phosphorescent guest material is 0.5wt%~2.5wt%.

5. The all-phosphorescent white OLED device according to claim 1 or 4, characterized in that, The doping concentration of the blue phosphorescent guest material is 6 wt%; the doping concentration of the red phosphorescent guest material is 1 wt%; and the doping concentration of the green phosphorescent guest material is 1.5 wt%.

6. The all-phosphorescent white OLED device according to claim 1, characterized in that, The phosphorescent guest doping material has ≥3 types.

7. The all-phosphorescent white OLED device according to claim 1, characterized in that, The thickness of the full phosphorescent single-emitting layer is 20~40nm.

8. The all-phosphorescent white OLED device according to claim 1 or 7, characterized in that, The thickness of the phosphorescent single-emitting layer is 25~30nm.

9. The all-phosphorescent white OLED device according to claim 1, characterized in that, The hole blocking layer has a thickness of 8-15 nm, and the electron blocking layer has a thickness of 5-15 nm.

10. A method for fabricating the all-phosphorescent white OLED device according to any one of claims 1 to 9, characterized in that, Includes the following steps: An anode, a hole injection layer, a hole transport layer, an electron blocking layer, a full phosphorescent single-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and a sealing layer are sequentially deposited on the surface of a substrate to obtain the full phosphorescent white OLED device.

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