Visible light-near infrared organic polymer photoelectric detector and preparation method thereof
By combining spin-coating-water transfer printing technology with PHJ and BHJ structures, the problems of process complexity and high dark current in the fabrication of photodetectors on non-planar substrates have been solved, realizing a high-performance organic photodetector with efficient photogenerated carrier separation and low dark current.
Patent Information
- Application Number
- CN202511166114.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-20
- Publication Date
- 2025-11-18
AI Technical Summary
When existing photodetectors are manufactured on large-area, flexible or non-planar substrates, the process is complex, the material compatibility is poor, and the traditional process results in high dark current and low photogenerated carrier separation efficiency.
A spin-coating-water transfer printing technique was used to combine planar heterojunction (PHJ) and bulk heterojunction (BHJ) to form a P-BHJ structure. The BHJ active layer was prepared by spin-coating on ITO, and the PHJ active layer film was prepared by water transfer printing, thus optimizing the deposition and pattern transfer of each layer of material.
Significantly reduces carrier transit time, improves carrier mobility and photoresponse, enables high-performance organic photodetectors, reduces dark current density, broadens spectral response, adapts to various substrates, simplifies manufacturing processes and reduces costs.
Smart Images
Figure CN120981082A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic photodetectors, specifically to a visible-near-infrared organic polymer photodetector based on spin coating-water transfer printing and its preparation method. Background Technology
[0002] In recent years, with the rapid development of flexible electronics and wearable devices, the demand for high-performance, low-cost, and simple photodetectors has been increasing. Traditional photodetector manufacturing processes, such as solution processing, spin coating, and vacuum evaporation, while achieving good results in the laboratory, often face numerous challenges when fabricating photodetectors on large-area, flexible, or non-planar substrates. These challenges include complex processes, poor material compatibility, and pattern distortion during the transfer process. This limits the practical application of traditional processes in industrial applications, necessitating an advanced manufacturing technology that simplifies the fabrication process, improves device consistency, and adapts to various substrates.
[0003] Water transfer printing, as an emerging transfer method, is gradually gaining attention in the field of photodetector manufacturing. The basic principle of this technology is to utilize the interfacial tension difference between water and organic solvents. When an organic solution is dropped onto a water surface, because the surface tension of the solvent is much lower than that of water, the organic solution quickly spreads on the water surface and forms a uniform thin film. As the solvent evaporates, the film solidifies and can then be transferred from the water surface to the target substrate through simple physical contact. This method does not require the use of traditional orthogonal solvents or the preparation of additional intermediate media, significantly reducing process complexity and broadening the range of material choices, enabling the application of some solvent-sensitive or demanding organic materials.
[0004] Water transfer printing offers several advantages in the fabrication of photodetectors. First, it enables the formation of high-quality, ultrathin organic films on water surfaces, significantly improving the light absorption and exciton separation efficiency of photodetectors. Second, because the transfer process avoids high-temperature or high-pressure treatments, the material layers within the device maintain good integrity and uniformity, avoiding the film defects and inhomogeneities common in traditional solution methods. Furthermore, water transfer printing is simple to operate, inexpensive, and adaptable to substrates of various shapes and sizes. Whether rigid flat panels, flexible thin films, or curved structures, it allows for high-precision transfer, greatly enhancing the flexibility and scalability of the manufacturing process.
[0005] On the other hand, multilayer photodetectors fabricated using water transfer printing technology also show significant advantages in reducing dark current, improving response speed, and achieving broadband detection. Traditional photodetectors often employ bulk heterojunction (BHJ) structures. Because the donor and acceptor materials are directly mixed, the charge injection barrier at the interface is easily lowered, leading to increased dark current. Planar heterojunction (PHJ) technology only allows exciton dissociation near the donor / acceptor interface, resulting in low exciton utilization. Combining BHJ and PHJ through spin-coating-water transfer printing technology allows for the separation of functional layers layer by layer, effectively controlling the thickness and interface quality between layers, thereby suppressing non-ideal carrier reverse injection, reducing dark current, and maintaining high photoresponse rate. Furthermore, water transfer printing technology has environmental advantages. Compared to traditional transfer processes, water as a medium is non-toxic and non-polluting, enabling high-precision pattern transfer while reducing the amount of organic solvents used.
[0006] In summary, the emergence of water transfer printing photodetector technology not only provides a novel manufacturing path for flexible electronics, wearable devices, and large-area displays and sensing systems, but also offers an effective way to solve problems such as process complexity, material limitations, and environmental pollution inherent in traditional manufacturing processes. Patented technologies within this context are driving the development of photodetectors towards higher sensitivity, wider spectral response, and lower costs by optimizing the transfer process and precisely controlling the deposition and pattern transfer of each layer of material, thus opening up broad prospects for future intelligent manufacturing and green production. Summary of the Invention
[0007] The problem this invention aims to solve is: how to provide a method for fabricating visible-near-infrared organic polymer photodetectors based on spin coating-water transfer printing. This method addresses the issues of numerous trapped states in the active layer, high dark current, and low photogenerated carrier separation and transmission efficiency in organic photodetectors. By combining planar heterojunctions (PHJ) and bulk heterojunctions (BHJ) through spin coating-water transfer printing, the ordered layer of PHJ improves carrier mobility, while BHJ shortens the transmission distance. The combination of these two significantly reduces carrier transit time, achieving a high-performance organic photodetector and ultimately solving the problem of low performance.
[0008] The technical solution of this invention is as follows: The visible-near-infrared organic polymer photodetector adopts an inverted structure, consisting of a substrate, a transparent conductive cathode ITO, an electron transport layer, a BHJ active layer, a PHJ donor active layer, a MoO3 hole transport layer, and a metal anode from bottom to top. The BHJ active layer is formed by wet spin-coating onto the ITO layer to form a bulk heterojunction (BHJ), achieving efficient exciton dissociation. A PHJ active layer film is prepared on the BHJ active layer by water transfer printing, forming a P-BHJ structure with the BHJ active layer, thereby improving carrier mobility and shortening the transmission distance, ultimately realizing a high-performance organic polymer photodetector.
[0009] Preferably, the electron transport layer material is ZnO with a thickness ranging from 20 to 80 nm.
[0010] The BHJ active layer is prepared from a mixed solution of electron donor material PM6 and acceptor non-fullerene material Y6, electron donor material PM6 and acceptor non-fullerene material Y6-BO, electron donor material PM6 and acceptor non-fullerene material Y6-HU, or electron donor material PM6 and acceptor non-fullerene material Y18, with a thickness ranging from 80 to 300 nm. The mass percentage of electron donor and acceptor in the mixed solution is 1:1 to 1:2, and the concentration of the mixed solution is 8 to 20 mg / ml. The PHJ active layer is prepared entirely from electron donor material PM6, with a thickness ranging from 80 to 100 nm; the concentration of the solution is 8 to 20 mg / ml.
[0011] Preferably, the metal anode material is Ag, and the thickness of the thin layer ranges from 80 to 100 nm.
[0012] Preferably, the substrate material is glass or a transparent polymer, wherein the transparent polymer material is one or more of polyethylene, polymethyl methacrylate, polycarbonate, polyurethane, polyimide, vinyl chloride resin or polyacrylic acid.
[0013] This invention also discloses a method for preparing a visible-near-infrared organic polymer organic photodetector, comprising the following steps: (1) Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO, and then dry it with nitrogen gas; (2) Spin-coating, printing or spraying an electron transport layer ZnO solution onto the surface of a transparent conductive cathode ITO, followed by thermal annealing; (3) The BHJ active layer was prepared by spin coating and then annealed; (4) The PHJ active layer was prepared by spin coating and then annealed; (5) At a vacuum degree of 4×10 -6 Under mbar conditions, MoO3 was evaporated onto the surface of the active layer to prepare a hole transport layer; (6) At a vacuum degree of 3×10 -6 Metal anodes are deposited by vapor deposition under mbar conditions.
[0014] Preferably, the heat annealing temperature of the electron transport layer in step (2) is in the range of 130 to 150 °C and the time range is 30 to 60 min.
[0015] Preferably, the annealing temperature of the BHJ active layer in step (3) is in the range of 80 to 120 °C and the time range is 10 to 30 min.
[0016] Preferably, the annealing temperature of the PHJ active layer in step (4) is in the range of 80 to 120 °C and the time range is 10 to 30 min.
[0017] Preferably, the hot annealing and low-temperature baking methods employ one or more of the following: constant temperature hot table heating, oven heating, far-infrared heating, and hot air heating.
[0018] The advantages of this invention are: 1. A P-BHJ structure is formed by combining bulk heterojunction (BHJ) and planar heterojunction (PHJ) through spin coating-water transfer printing. BHJ can significantly increase the donor / acceptor area, shorten the transmission distance, and achieve efficient exciton dissociation; PHJ can improve the stability of the active layer. The thick active layer ensures low dark current. The combination of the two significantly reduces the carrier transit time, realizes a high-performance organic photodetector, and ultimately realizes a high-performance organic photodetector device.
[0019] 2. By adopting the inverted organic polymer photodetector system of P-BHJ, dark-state charge carriers can be effectively blocked, thereby significantly reducing dark current density and improving the performance of organic polymer photodetectors; at the same time, spin coating-water transfer printing is a universal method that can be widely used in the fabrication of organic photodetectors. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the visible-near-infrared organic polymer organic photodetector involved in this invention; Figure 2 This is a schematic diagram of the active layer distribution using spin coating-water transfer printing in this invention; The figures are labeled as follows: 1-substrate, 2-transparent conductive cathode ITO, 3-ZnO electron transport layer, 4-BHJ active layer, 5-PHJ active layer, 6-MoO3 anode buffer layer, 7-metal anode, 8-donor, 9-acceptor. Detailed Implementation
[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0022] Example 1 (Control Group): 1. Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO with a surface roughness of less than 1 nm, and then dry it with nitrogen gas. 2. A ZnO solution (3.15 g Zn(OAc)2 and 0.900 mL ethanolamine dissolved in 29.1 mL 2-methoxyethanol) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared by spin-coating (5000 rpm, 40 s, 40 nm), and the resulting film was subjected to thermal annealing (150 ℃, 30 min). 3. A PM6:Y6 (1:1.2, 16 mg / ml) solution was dropped onto the electron transport layer, and a BHJ active layer was prepared by spin coating (3000 rpm, 40 s, 80 nm). The resulting film was then subjected to thermal annealing (100 ℃, 15 min). 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition; 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer; 6. Under standard test conditions: the photocurrent density of the device at AM 1.5 G was measured ( J ph The value is 1.38 × 10⁻⁶. -2 A / cm 2 Dark current density ( J dark The value is 7.93 × 10. -8 A / cm 2 The external quantum efficiency (EQE) is 80.25%, and the detectivity is... D *) is 6.14 × 10 12 Jones, responsiveness ( R The impedance is 0.334 A / W, and the linear dynamic range (LDR) is 137 dB.
[0023] Example 2: 1. Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO with a surface roughness of less than 1 nm, and then dry it with nitrogen gas. 2. A ZnO solution (3.15 g Zn(OAc)2 and 0.900 mL ethanolamine dissolved in 29.1 mL 2-methoxyethanol) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared by spin-coating (5000 rpm, 50 s, 40 nm), and the resulting film was subjected to thermal annealing (150 ℃, 30 min). 3. A PM6:Y6 (1:1.2, 16 mg / ml) solution was dropped onto the electron transport layer, and a BHJ active layer was prepared by spin coating (3000 rpm, 40 s, 80 nm). The resulting film was then subjected to thermal annealing (100 ℃, 15 min). 4. A PM6 film (16 mg / ml) was transferred onto the BHJ active layer via water transfer. 5. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition; 6. Deposit a metallic anode Ag (100 nm) onto the hole transport layer; 7. Under standard test conditions: the photocurrent density of the device at AM 1.5 G was measured ( J ph 7.74×10 -2 A / cm 2 Dark current density ( J dark The value is 4.51 × 10. -10 A / cm 2 The external quantum efficiency (EQE) is 85.01%, and the detectivity is... D *) is 2.67 × 10 13 Jones, responsiveness ( R The impedance is 0.356 A / W, and the linear dynamic range (LDR) is 212 dB.
[0024] Example 3: 1. Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO with a surface roughness of less than 1 nm, and then dry it with nitrogen gas. 2. A ZnO solution (3.15 g Zn(OAc)2 and 0.900 mL ethanolamine dissolved in 29.1 mL 2-methoxyethanol) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared by spin-coating (5000 rpm, 50 s, 40 nm), and the resulting film was subjected to thermal annealing (150 ℃, 30 min). 3. A PM6:Y6 (1:1.2, 16 mg / ml) solution was dropped onto the electron transport layer, and a BHJ active layer was prepared by spin coating (3000 rpm, 40 s, 80 nm). The resulting film was then subjected to thermal annealing (100 ℃, 15 min). 4. A PM6 film (16 mg / ml) was transferred onto the BHJ active layer via water transfer. 5. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition; 6. Deposit a metallic anode Ag (100 nm) onto the hole transport layer; 7. Under standard test conditions: the photocurrent density of the device at AM 1.5 G was measured ( J ph 6.38×10 -2 A / cm 2 Dark current density ( J dark The value is 8.01 × 10 -10 A / cm 2 The external quantum efficiency (EQE) is 82.55%, and the detectivity is... D *) is 1.98 × 10 13 Jones, responsiveness ( R The impedance is 0.346 A / W, and the linear dynamic range (LDR) is 174 dB.
[0025] Example 4: 1. Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO with a surface roughness of less than 1 nm, and then dry it with nitrogen gas. 2. A ZnO solution (3.15 g Zn(OAc)2 and 0.900 mL ethanolamine dissolved in 29.1 mL 2-methoxyethanol) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared by spin-coating (5000 rpm, 50 s, 40 nm), and the resulting film was subjected to thermal annealing (150 ℃, 30 min). 3. A PM6:Y6 (1:1.2, 16 mg / ml) solution was dropped onto the electron transport layer, and a BHJ active layer was prepared by spin coating (3000 rpm, 40 s, 80 nm). The resulting film was then subjected to thermal annealing (100 ℃, 15 min). 4. A PM6 film (16 mg / ml) was transferred onto the BHJ active layer via water transfer. 5. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition; 6. Deposit a metallic anode Ag (100 nm) onto the hole transport layer; 7. Under standard test conditions: the photocurrent density of the device at AM 1.5 G was measured ( J ph 4.21×10 -2 A / cm 2 Dark current density ( Jdark The value is 1.12 × 10⁻⁶. -9 A / cm 2 The external quantum efficiency (EQE) is 82.32%, and the detectivity is... D *) is 1.77 × 10 13 Jones, responsiveness ( R The impedance is 0.345 A / W, and the linear dynamic range (LDR) is 153 dB.
[0026] Table 1: Performance parameters of organic photodetectors
[0027] It can be seen that: the organic polymer photodetectors prepared by spin coating-water transfer printing (i.e., the organic photodetectors prepared in Examples 2-4) have better performance than those prepared without water transfer printing (i.e., the organic photodetectors prepared in Example 1). J ph Get bigger J dark Significantly reduced, EQE, D Both * show improvement, with LDR receiving a significant boost, ensuring a wider light response range and enhancing the performance of organic photodetectors. The active layer (e.g., obtained through spin-coating-water transfer printing) is... Figure 2 The BHJ active layer is spin-coated onto the ITO layer using a wet method to form a bulk heterojunction (BHJ), achieving efficient exciton dissociation. A PHJ active layer film is then prepared on the BHJ active layer via water transfer printing, forming a P-BHJ structure with the BHJ active layer. This improves carrier mobility and shortens the transmission distance, ultimately realizing a high-performance organic photodetector. Through systems with different donor and acceptor materials, the spin-coating-water transfer printing process has been verified as a universal process for fabricating organic photodetectors, playing a significant role in improving their performance.
[0028] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.
Claims
1. A visible-near-infrared organic polymer photodetector, characterized in that, The organic polymer photodetector adopts an inverted structure, consisting of a substrate, a transparent conductive cathode ITO, an electron transport layer, a BHJ active layer, a PHJ donor active layer, a MoO3 hole transport layer, and a metal anode from bottom to top. The BHJ active layer is formed by wet spin-coating onto the ITO to create a bulk heterojunction, enabling efficient exciton dissociation. A PHJ active layer film is then prepared on top of the BHJ active layer via water transfer printing, forming a P-BHJ structure with the BHJ active layer. This improves carrier mobility and shortens the transmission distance, ultimately achieving a high-performance organic polymer photodetector.
2. The visible-near-infrared organic polymer photodetector according to claim 1, characterized in that: The electron transport layer material is ZnO, with a thickness ranging from 20 to 80 nm.
3. The visible-near-infrared organic polymer photodetector according to claim 1, characterized in that: The BHJ active layer is prepared from a mixed solution of electron donor material PM6 and acceptor non-fullerene material Y6, electron donor material PM6 and acceptor non-fullerene material Y6-BO, electron donor material PM6 and acceptor non-fullerene material Y6-HU, or electron donor material PM6 and acceptor non-fullerene material Y18, with a thickness ranging from 80 to 300 nm. The mass percentage of electron donor and acceptor in the mixed solution is 1:1 to 1:2, and the concentration of the mixed solution is 8 to 20 mg / ml.
4. The visible-near-infrared organic polymer photodetector according to claim 1, characterized in that: The metal anode material is Ag, and the thickness of the thin layer ranges from 80 to 100 nm.
5. The visible-near-infrared organic polymer photodetector according to claim 1, characterized in that: The substrate material is glass or a transparent polymer, and the transparent polymer material is one or more of polyethylene, polymethyl methacrylate, polycarbonate, polyurethane, polyimide, vinyl chloride resin and polyacrylic acid.
6. A method for preparing a visible-near-infrared organic polymer photodetector, used to prepare the visible-near-infrared organic polymer photodetector as described in any one of claims 1-5, characterized in that, The preparation process includes the following steps: (1) Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO, and then dry it with nitrogen gas; (2) Spin-coating, printing or spraying an electron transport layer ZnO solution onto the surface of a transparent conductive cathode ITO, followed by thermal annealing; (3) The BHJ active layer was prepared by spin coating and then annealed; (4) The PHJ active layer was prepared by spin coating and then annealed; (5) At a vacuum degree of 4×10 -6 Under mbar conditions, MoO3 was evaporated onto the surface of the active layer to prepare a hole transport layer; (6) At a vacuum degree of 3×10 -6 Metal anodes are deposited by vapor deposition under mbar conditions.
7. The method for preparing the visible-near-infrared organic polymer photodetector according to claim 6, characterized in that, The heat annealing temperature range for the electron transport layer in step (2) is 130–150 °C, and the time range is 30–60 min.
8. The method for preparing the visible-near-infrared organic polymer organic photodetector according to claim 6, characterized in that, The annealing temperature range of the BHJ active layer in step (3) is 80-120 °C, and the time range is 10-30 min.
9. The method for preparing the visible-near-infrared organic polymer photodetector according to claim 6, characterized in that, The annealing temperature range for the PHJ active layer in step (4) is 80–120 °C, and the time range is 10–30 min.
10. The method for preparing a visible-near-infrared organic polymer photodetector according to claim 6, characterized in that, The heat annealing and low-temperature baking methods employ one or more of the following: constant temperature hot table heating, oven heating, far-infrared heating, and hot air heating.