Miniature silicon-based top-emitting OLED device with high hole injection rate

Abstract

The invention relates to the technical field of organic light-emitting diode manufacturing, in particular to a miniature silicon-based top-emitting OLED device with a high hole injection rate, which comprises a silicon-based CMOS (complementary metal oxide semiconductor) driving circuit substrate, a multilayer composite anode, an organic light-emitting unit, a cathode layer, an anti-reflection layer, a thin film sealing layer and a glass cover plate. According to the device, hole injection and energy level alignment are facilitated, the hole injection efficiency of the device is improved, and meanwhile the problems that the hole injection efficiency and conductivity are reduced due to anodic oxidation generated in the device manufacturing process are solved.

Description

Technical Field

[0001] The invention relates to the technical field of organic light emitting diode manufacturing, and in particular to a micro silicon-based top-emitting OLED device with a high hole injection rate. Background Art

[0002] With the widespread application of silicon-based top-emitting OLED devices in virtual reality devices such as AR and VR, the brightness requirement of silicon-based top-emitting OLED devices should be ≥5000 cd / m 2 , pixel density ≥ 2500PPI. Due to device configuration limitations, the brightness of traditional OLEDs can drop by up to 70% when coupled to a silicon backplane, parameters that are far below the minimum brightness requirements for new near-eye display applications. Currently, top-emitting OLEDs use highly reflective anodes to optically isolate the thin-film transistor from the OLED to enhance its brightness output. Although pure aluminum has the highest reflectivity in the UV, visible, and near-infrared light spectra, many OLED microdisplay manufacturers choose to use silver, nickel, gold, or other metals with low surface reactivity with oxygen. Because aluminum tends to grow an insulating oxide layer during the patterning process of the metal anode, it severely hinders the hole injection performance and conductivity of the anode, resulting in a decrease in the brightness and efficiency of the device.

[0003] In addition, silicon-based top-emitting OLED devices also include organic structures stacked in layers between electrodes. In the early development of the device, the larger pixel channel caused the lateral leakage of the organic layer to be ignored to a certain extent. With the development of the stacked structure and the increase in pixel density, the electrical crosstalk caused by the lateral leakage of the organic layer of the OLED device has increased significantly, resulting in low color gamut of the device, impure monochrome images and color distortion. Usually, a groove or retaining wall is set above the pixel limiting layer in the OLED device to block the continuity of the hole injection layer, thereby reducing the degree of crosstalk of the lateral current. However, the groove or retaining wall will cut off the metal cathode, resulting in increased impedance, increased power consumption, and poor uniformity. Replacing the hole transport material with poor conductivity or using a hole transport material instead of a hole injection material can also reduce the crosstalk problem, but these two methods will increase the driving voltage of the OLED device and reduce the efficiency of the device. Summary of the invention

[0004] In order to meet the ever-increasing demands of the application market and solve the problems of low color gamut, low luminous efficiency and low device brightness caused by lateral leakage and natural anode oxide insulating layer, the present invention proposes a micro silicon-based top-emitting OLED device with a high hole injection rate.

[0005] The micro silicon-based top-emitting OLED device with high hole injection rate of the present invention is characterized in that the device comprises a silicon-based CMOS driving circuit substrate, a composite anode, an organic light-emitting unit, a cathode layer, an anti-reflection layer, a thin film sealing layer and a glass cover plate: The composite anode adopts a multi-layer composite structure, and one structure of the multi-layer composite structure is: the first layer is selected from any one of ITO and Ti; the second layer is selected from Al; the third layer is selected from Al2O3; the fourth layer is selected from any one of MoO3, WO3 or ReO3; the thickness of the composite anode is 100-200nm; Another structure of the multilayer composite structure is: the first layer is made of Al; the second layer is made of Al2O 3； The third layer is made of any one of MoO3, WO3 or ReO3; the thickness of the composite anode is 100-200nm.

[0006] The thickness of the Ti is 5-10 nm; The thickness of the Al is 100-150 nm; The thickness of the Al2O3 is 2-4 nm; The thickness of the MoO3, WO3 or ReO3 is 2-4 nm.

[0007] The silicon-based CMOS driving circuit substrate adopts a silicon-based CMOS driving circuit with a wire frame of 0.18μm, 0.18μm, 0.18μm or 90nm.

[0008] The organic light emitting unit includes a hole transport layer, a light emitting layer, an electron transport layer and an electron generating layer.

[0009] A micro silicon-based top-emitting stacked OLED device with a high hole injection rate is characterized in that at least two organic light-emitting units are stacked, and a charge generation layer is arranged between adjacent organic light-emitting units.

[0010] The charge generation layer is composed of p / n type semiconductor materials: the p type semiconductor material is composed of metal oxide, and the n type semiconductor material is prepared from electron transport materials doped with low work function metal or metal oxide.

[0011] A method for preparing a micro silicon-based top-emitting OLED device with a high hole injection rate, characterized in that the preparation method of the composite anode is: The silicon-based CMOS drive circuit substrate is coated with photoresist PR, and then exposed and developed. The lower layer of Ti and / or Al is prepared by vacuum evaporation, and the vacuum degree is maintained at 10 -5 Pa below, the substrate temperature is controlled at 100-150 ° C, the rate is controlled at 5Å / s; transferred to the UVO treatment chamber, Al2O3 is prepared by UVO treatment; MoO3, WO3 or ReO3 is prepared by vacuum evaporation, and the pressure is maintained at 10 -5 Below pa, the substrate temperature is controlled at 100-150℃, and the evaporation rate is maintained at 0.5Å / s; finally, a stripping device is used to remove excess photoresist PR and anode film layers.

[0012] Furthermore, the p / n type semiconductor material is prepared on the composite anode by vacuum evaporation.

[0013] The micro silicon-based top-emitting OLED device with high hole injection rate of the present invention uses UVO treatment to grow Al2O3 on the Al surface, which can simulate the oxide layer grown naturally under environmental conditions. The microstructure of Al2O3 obtained by this method has certain pinholes, such as Figure 3 As shown, the diffusion of MoO3 to the underlying aluminum through the Al2O3 / MoO3 oxide heterojunction can reduce the oxidation state of MoO3 near the anode interface, reduce the hole injection barrier, facilitate hole injection and energy level alignment, and improve the hole injection efficiency of the device. At the same time, it avoids the problems of reduced hole injection efficiency and conductivity caused by anode oxidation generated during the device manufacturing process.

[0014] Compared with the single-layer OLED device structure, the stacked structure device has the advantages of high brightness, low power consumption and long life. The multi-layer composite anode retains the high reflectivity of the Al anode, which can further enhance the brightness output and improve the life, and can work at a low conduction voltage. Using the multi-layer composite anode as a hole injection layer can avoid the lateral leakage problem of the organic layer caused by the shared hole injection layer, improve the color gamut, contrast, saturation and color purity of the device, and further meet the application of micro OLED devices in near-eye display devices such as VR / AR. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of an OLED device.

[0016] Figure 2 Schematic diagram of the structure of a stacked OLED device.

[0017] Figure 3 Schematic diagram of the composite anode production process.

[0018] Figure 4 This is an XPS graph of the composite anode of the present invention; wherein the abscissa is the binding energy and the ordinate is the intensity.

[0019] Figure 5 This is a distribution diagram of the composite anode of the present invention. DETAILED DESCRIPTION

[0020] Example 1: A micro silicon-based top-emitting blue light OLED device with high hole injection rate, the preparation method comprising the following steps: Step 1: Prepare a patterned multilayer composite anode on a silicon-based CMOS drive circuit substrate made of α-Si / LTPS / LTPO / Oxide using a photolithography process and a vacuum evaporation process.

[0021] Specifically, a photoresist PR is coated on the substrate and then exposed and developed, and the lower layer of Ti and Al is prepared by vacuum evaporation, and the vacuum degree is maintained at 10 -5 The substrate temperature was controlled at 100-150°C and the rate was controlled at 5 Å / s. The metal Ti anode was prepared with a thickness of 10 nm and the metal Al anode was prepared with a thickness of 150 nm. After completion, the anode was transferred to the UVO treatment chamber and an Al2O3 anode was prepared by UVO treatment with a thickness of 4 nm. The upper MoO3 anode was then prepared by vacuum evaporation and the pressure was kept at 10 -5 Pa below, the substrate temperature is controlled at 100-150 ° C, the evaporation rate is maintained at 0.5 Å / s, and the preparation thickness is 4 nm; the excess photoresist PR and anode film layer are removed using a stripping device to obtain Figure 4 The multi-layer composite anode shown; Step 2: Use vacuum evaporation process to deposit hole transport layer, light-emitting layer, electron transport layer, electron generation layer, semi-transparent cathode Mg:Ag and anti-reflection layer on the anode pixel point in sequence; wherein, the light-emitting layer is composed of blue light host (BH) and blue light guest material (BD) through doping to achieve blue light emission.

[0022] Step three, use atomic layer deposition, chemical vapor deposition, molecular layer deposition and other processes to complete the device thin film packaging process; the sealing process can use Al2O3 film, SiO2 film, SiNx film, parylene film or organic and inorganic composite multilayer film and other inorganic and polymer composite films for sealing.

[0023] The light-emitting layer used in this embodiment is doped with a blue light host (BH) and a blue light guest material (BD), and there is no need to consider the lateral leakage problem.

[0024] Step 4: Stick a glass sheet on the film sealing layer for protection.

[0025] Example 2: A micro silicon-based top-emitting stacked OLED device with high hole injection rate, using MoO3 as the hole injection layer can avoid the lateral leakage problem of the organic layer, the current efficiency can reach 5.5 cd / A, and the color gamut can reach 86-90%. The preparation method includes the following steps: Step 1: Use photolithography and vacuum evaporation processes to prepare a patterned multilayer composite anode on a silicon-based driving substrate of a COMS driving circuit made of α-Si / LTPS / LTPO / Oxide.

[0026] Specifically, a photoresist PR is coated on the substrate and then exposed and developed, and the lower layer of Ti and Al is prepared by vacuum evaporation, and the vacuum degree is maintained at 10 -5The substrate temperature was controlled at 100-150°C and the rate was controlled at 5 Å / s. The metal Ti anode was prepared with a thickness of 10 nm and the metal Al anode was prepared with a thickness of 150 nm. After completion, the anode was transferred to the UVO treatment chamber and an Al2O3 anode was prepared by UVO treatment with a thickness of 4 nm. The upper MoO3 anode was then prepared by vacuum evaporation and the pressure was kept at 10 -5 Below pa, the substrate temperature is controlled at 100-150°C, the evaporation rate is maintained at 0.5 Å / s, and the preparation thickness is 4 nm; a stripping device is used to remove excess photoresist PR and anode film layers to obtain a composite anode.

[0027] Step 2: Vacuum evaporation is used to deposit different functional layer materials on the anode pixel points in sequence; the specific organic structure is as follows Figure 2 As shown, from bottom to top are the first organic light-emitting unit, the charge generation layer, the second light-emitting unit, the semi-transparent cathode Mg:Ag and the anti-reflection layer; Specifically, the first organic light-emitting unit is composed of a first hole transport layer, a blue light-emitting layer, a first electron transport layer and a first electron generation layer; the charge generation layer is made of p / n type semiconductor material; the second organic light-emitting unit is composed of a second hole transport layer, a yellow light-emitting layer, a second electron transport layer and a second electron generation layer. Under the action of an electric field, the charge generation layer has the ability to generate and separate carriers - electrons and holes through the heterojunction of the n / p semiconductor interface, and injects the generated electrons / holes into the first organic light-emitting unit or the second organic light-emitting unit to make it emit light. Step three, use atomic layer deposition, chemical vapor deposition, molecular layer deposition and other processes to complete the device thin film packaging process; the sealing process can use Al2O3 film, SiO2 film, SiNx film, parylene film or organic and inorganic composite multilayer film and other inorganic and polymer composite films for sealing.

[0028] Step 4: Stick a glass sheet on the film sealing layer for protection.

Claims

1. A micro silicon-based top-emitting OLED device with high hole injection rate, characterized in that The device consists of a silicon-based CMOS drive circuit substrate, a composite anode, an organic light-emitting unit, a cathode layer, an anti-reflection layer, a thin film sealing layer and a glass cover: The composite anode adopts a multi-layer composite structure, and one structure of the multi-layer composite structure is: the first layer is selected from any one of ITO and Ti; the second layer is selected from Al; the third layer is selected from Al2O3; the fourth layer is selected from any one of MoO3, WO3 or ReO3; the thickness of the composite anode is 100-200nm; Another structure of the multilayer composite structure is: the first layer is made of Al; the second layer is made of Al2O 3； The third layer is made of any one of MoO3, WO3 or ReO3; the thickness of the composite anode is 100-200nm.

2. The micro silicon-based top-emitting OLED device with high hole injection rate as claimed in claim 1, characterized in that: The thickness of Ti is 5-10 nm; The thickness of the Al is 100-150 nm; The thickness of the Al2O3 is 2-4 nm; The thickness of the MoO3, WO3 or ReO3 is 2-4 nm.

3. The micro silicon-based top-emitting OLED device with high hole injection rate according to claim 1, characterized in that The silicon-based CMOS driving circuit substrate adopts a silicon-based CMOS driving circuit with a wire frame of 0.18μm, 0.18μm, 0.18μm or 90nm.

4. The micro silicon-based top-emitting OLED device with high hole injection rate according to claim 1, characterized in that: The organic light emitting unit includes a hole transport layer, a light emitting layer, an electron transport layer and an electron generating layer.

5. A micro silicon-based top-emitting stacked OLED device with high hole injection rate, characterized in that At least two organic light-emitting units are stacked, and a charge generation layer is arranged between adjacent organic light-emitting units. The charge generation layer is composed of p / n type semiconductor material.

6. A method for preparing a micro silicon-based top-emitting OLED device with a high hole injection rate, characterized in that The preparation method of the composite anode is as follows: a photoresist PR is coated on a silicon-based CMOS drive circuit substrate, and then exposed and developed, and a lower layer of Ti and / or Al is prepared by vacuum evaporation, and the vacuum degree is maintained at 10 -5 pa below, the substrate temperature is controlled at 100-150℃, the rate is controlled at 5 Å / s; transferred to the UVO treatment chamber, Al2O3 is prepared by UVO treatment; MoO3, WO3 or ReO3 is prepared by vacuum evaporation, and the pressure is maintained at 10 -5 Below pa, the substrate temperature is controlled at 100-150℃, and the evaporation rate is maintained at 0.5 Å / s; a stripping device is used to remove excess photoresist PR and anode film layers.

Images