Organic photoelectric detector based on polymer N2200 doped small molecules and preparation method thereof

Abstract

The invention discloses an organic photoelectric detector based on polymer N2200 doped small molecules and a preparation method thereof, and relates to the technical field of organic photoelectric detectors, the organic photoelectric detector adopts an inverted structure, and comprises a substrate, a transparent conductive cathode ITO, a polymer N2200 doped heat exciton blue light material electron transport layer and a PM6: Y12 active layer from bottom to top in sequence, a MoO3 hole transport layer and a metal anode; the polymer N2200 doped heat exciton blue light material is used as an electron transport layer, and the N2200 and the heat exciton blue light material are spin-coated on the ITO upper layer through a wet method, so that the hole blocking capability of the heat exciton blue light material under reverse bias voltage can be enhanced, electrons can be blocked in a dark state, the dark current of the organic photoelectric detector can be reduced, and the organic photoelectric detector can be applied to the field of organic photoelectric detectors. The charge dissociation and transmission capability in the active layer is improved, ohmic contact is promoted, the contact resistance formed between interfaces is reduced, the charge transmission capability between different functional layers is further improved, and the purpose of improving various performance parameters of the organic photoelectric detector is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic photodetectors, and particularly relates to an organic photodetector based on polymer N2200 doped small molecules and a preparation method thereof. BACKGROUND

[0002] As a new type of photovoltaic device, organic photodetectors (OPDs) have attracted extensive attention in recent years due to their unique advantages in flexible electronics, biomedical sensing, environmental monitoring, and optical communication. Compared with traditional inorganic semiconductor photodetectors, organic photodetectors have the characteristics of solution processable materials, lightweight and flexible, large-area manufacturing, and tunable spectral response, which provide a broad space for their application in the next generation of electronic devices.

[0003] The development of organic photodetectors can be traced back to the 1980s. The early devices had limitations in photoelectric conversion efficiency, stability, and device lifetime due to the limited performance of organic semiconductor materials. However, with the rapid development of organic semiconductor material science, especially the emergence of high-performance polymer semiconductors (such as P3HT, PTB7) and small molecule semiconductors (such as ITIC, C60), the performance of organic photodetectors has been significantly improved. In recent years, the combination of perovskite materials and quantum dot materials with organic semiconductors has further expanded the spectral response range of the device, improving the detection sensitivity and response speed. In terms of device structure, organic photodetectors have evolved from single-layer structures to double-layer heterojunctions, planar heterojunctions, and vertical heterojunctions, significantly improving the separation and transport efficiency of carriers. In addition, by introducing micro-nano structures and photonic crystals, the light capture capability of the device has been further enhanced, significantly improving the photoelectric conversion efficiency and signal-to-noise ratio. The application of organic photodetectors in flexible and wearable electronic devices is an important research direction. Due to the flexibility and processability of organic semiconductor materials, organic photodetectors can be integrated into flexible substrates and maintain stable performance under large-scale bending and stretching conditions, which provides new technical support for wearable health monitoring devices. For example, organic photodetectors can be used to monitor physiological signals such as heart rate and blood oxygen saturation in real time, providing accurate data support for personalized medicine and remote health monitoring.

[0004] In addition, organic photodetectors also show important application potential in environmental monitoring, such as ultraviolet and infrared detection technology can be applied to air quality monitoring, water quality detection and other scenes, helping to improve the level of environmental management. In the field of optical communication, organic photodetectors play an important role in high-speed optoelectronic transmission systems due to their fast response and low power consumption. Although organic photodetectors have made significant progress in performance, they still face many challenges in device stability, dark current suppression, long-term service life, and large-area uniformity. Future development trends will focus on developing new high-performance organic semiconductor materials, optimizing device structure design, reducing device dark current, and improving photoelectric conversion efficiency and stability. At the same time, the deep integration of organic photodetectors with artificial intelligence and Internet of Things technology will further expand their application fields and promote their widespread application in intelligent medical care, environmental monitoring, flexible display, and human-computer interaction. With continuous breakthroughs in materials science, device technology, and system integration technology, organic photodetectors will play an increasingly important role in future high-performance optoelectronic systems, bringing more possibilities for the development of new-generation optoelectronic technology. SUMMARY

[0005] The problem to be solved by the present application is: how to provide an organic photodetector based on polymer N2200 doped with small molecules and a preparation method thereof, aiming to solve the problem that the electron transport layer in the organic photodetector cannot achieve the blocking effect under dark state, resulting in reduced device performance, while providing faster electron transport capability, thereby improving the separation, transport and interface transfer efficiency of photo-generated carriers, and ultimately solving the problem of reduced device performance.

[0006] The technical scheme of the present application is: The present application provides an organic photodetector based on polymer N2200 doped with small molecules, which adopts an inverted structure, and from bottom to top, it is a substrate, a transparent conductive cathode ITO, a polymer N2200 doped with hot exciton blue light material as an electron transport layer, a PM6:Y12 active layer, a MoO3 hole transport layer, and a metal anode; the polymer N2200 doped with hot exciton blue light material as the electron transport layer, the polymer N2200 and the hot exciton blue light material are coated on the ITO upper layer by wet spinning.

[0007] Further, the material of the electron transport layer is N2200:PPIAn2N-CH3, N2200:PPIAn2N-CN, N2200:PPIAn2N-F, N2200:PyIAn1N, N2200:PyIAn2N and N2200:PyIAnp, and the thickness range is 20-50 nm.

[0008] Further, the molecular structure formula of the hot exciton blue light material is as follows: .

[0009] Further, the PM6:Y12 active layer is prepared from a mixed solution of the electron donor material PM6 and the acceptor non-fullerene material Y12, and has a thickness in the range of 50-300 nm; the mass percentage of PM6:Y12 in the mixed solution is 1:1-1:2, and the concentration of the mixed solution is 6-15 mg / ml.

[0010] Further, the material of the metal anode is Ag, and the thickness of the thin layer is in the range of 80-100 nm.

[0011] Further, the substrate material is glass or a transparent polymer material, and the transparent polymer material is one or more of polyethylene, polymethyl methacrylate, polycarbonate, polyurethane, polyimide, chlorovinyl resin or polyacrylic acid.

[0012] The application further provides a preparation method of the polymer N2200 doped small molecule-based organic photodetector. The substrate composed of a transparent substrate and a transparent conductive cathode ITO is cleaned, and then dried with nitrogen after cleaning; The electron transport layer N2200:PPIAn2N-CH3, N2200:PPIAn2N-CN, N2200:PPIAn2N-F, N2200:PyIAn1N, N2200:PyIAn2N and N2200:PyIAnp is spin-coated, printed or sprayed on the surface of the transparent conductive cathode ITO, and then heat annealed; The PM6:Y12 active layer is prepared by a spin coating process and annealed; The MoO3 is evaporated on the surface of the active layer under the condition of a vacuum degree of 3x10 -3 Pa, to prepare a hole transport layer; The metal anode is evaporated under the condition of a vacuum degree of 3x10 -4 Pa.

[0013] Further, the heat annealing temperature of the electron transport layer is in the range of 200-250 ℃, and the time is in the range of 1-2 h.

[0014] Further, the heat annealing is one or more of constant temperature hot table heating, oven heating, far infrared heating and hot air heating.

[0015] The application has the following beneficial effects compared with the prior art: 1. By using a simple doping process on polymer N2200, the lower HOMO energy level of polymer N2200 can enhance the hole blocking ability of thermal exciton blue light material under reverse bias. At the same time, thermal exciton blue light material blocks electrons in the dark state, further reducing the dark current of organic photodetectors and improving the performance of organic photodetectors.

[0016] 2. By adopting an inverted organic photodetector system with a bulk heterojunction, ohmic contacts are effectively formed between the electron transport layer of the polymer N2200 / thermal exciton blue light material and the lower active layer (electron acceptor Y12 part), and the upper active layer (electron donor PM6 part) and the MoO3 anode buffer layer, respectively. This reduces the contact resistance between different functional layers and effectively improves the charge transport capability between different functional layers.

[0017] 3. Small molecules have better flatness and are easier to process. Through small molecule doping, the electron transport layer polymer N2200 / thermal exciton blue light material is ensured to have very good contact with the active layer, which can effectively improve the electron transport capability and improve the performance of organic photodetectors. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an organic photodetector based on polymer N2200 doped small molecules, which is involved in this invention. Figure 2 This is a schematic diagram of the electron transport layer phase distribution of the polymer N2200-doped thermal exciton blue light material used in this invention.

[0019] The figures are labeled as follows: 1-substrate; 2-transparent conductive cathode ITO; 3-polymer N2200 / thermal exciton blue light material electron transport layer; 4-PM6:Y12 active layer; 5-MoO3 anode buffer layer; 6-metal anode; 7-polymer N2200 phase morphology; 8-small molecule thermal exciton blue light material phase morphology. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Comparative example: 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. An N2200 (10 mg / ml) solution 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 1.45 × 10⁻⁶. -2 A / cm 2 The dark current density (Jdark) is 7.67 × 10⁻⁶. -6 A / cm², external quantum efficiency (EQE) of 75.42%, detectivity (D*) of 2.53 × 10⁻⁶. 9 Jones, with a response rate (R) of 0.282 A / W.

[0022] Example 1: 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 solution of N2200:PPIAn2N-CH3 (1:1.2, 10 mg / ml) 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 2.06 × 10⁻⁶. -2 A / cm2, dark current density (Jdark) is 2.36×10 -7 A / cm², external quantum efficiency (EQE) of 81.35%, detectivity (D*) of 1.63 × 10⁻⁶. 10Jones, with a response (R) of 0.314 A / W.

[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 solution of N2200:PPIAn2N-CN (1:1.2, 10 mg / ml) 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 2.31 × 10⁻⁶. -2 A / cm2, dark current density (Jdark) is 5.73×10 -7 A / cm 2 The external quantum efficiency (EQE) is 80.07%, and the detectivity (D*) is 9.62 × 10⁻⁶. 9 Jones, with a response rate (R) of 0.305 A / W.

[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 solution of N2200:PPIAn2N-F (1:1.2, 10 mg / ml) 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 2.76 × 10⁻⁶. -2 A / cm 2 The dark current density (Jdark) is 7.65 × 10⁻⁶. -8 A / cm², external quantum efficiency (EQE) of 83.22%, detectivity (D*) of 2.64 × 10⁻⁶. 11 Jones, with a response rate (R) of 0.311 A / W.

[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 solution of N2200:PyIAn1N (1:1.2, 10 mg / ml) 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 3.08 × 10⁻⁶. -2 A / cm 2 The dark current density (Jdark) is 6.81 × 10⁻⁶. -8 A / cm 2 The external quantum efficiency (EQE) is 81.27%, and the detectivity (D*) is 8.05 × 10⁻⁶.10 Jones, with a response rate (R) of 0.307 A / W.

[0026] Example 5: 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 solution of N2200:PyIAn2N (1:1.2, 10 mg / ml) 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 3.15 × 10⁻⁶. -2 A / cm2, dark current density (Jdark) is 4.32×10 -8 A / cm 2 The external quantum efficiency (EQE) is 79.76%, and the detectivity (D*) is 4.05 × 10⁻⁶. 11 Jones, with a response rate (R) of 0.296 A / W.

[0027] Example 6: 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. An N2200:PyIAnp (1:1.2, 10 mg / ml) solution 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 (200 ℃, 2 h). 3. A PM6:Y12 (1:1.2, 10 mg / ml) solution was dropped onto the electron transport layer, and an active layer was prepared by spin coating (2000 rpm, 40 s, 150 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 measured photocurrent density (Jph) of the device at 58 mW was 3.83 × 10⁻⁶. -2 A / cm 2 The dark current density (Jdark) is 3.35 × 10⁻⁶. -8 A / cm 2 The external quantum efficiency (EQE) is 82.79%, and the detectivity (D*) is 2.03 × 10⁻⁶. 11 Jones, with a response rate (R) of 0.323 A / W.

[0028] like Figure 1 As shown, an organic photodetector based on polymer N2200 doped small molecules includes a substrate 1; a transparent conductive cathode ITO 2; an electron transport layer of polymer N2200 / thermal exciton blue light material 3; a PM6:Y12 active layer 4; a MoO3 anode buffer layer 5; and a metal anode 6.

[0029] like Figure 2 The diagram shows the phase distribution of the electron transport layer in the N2200-doped thermal exciton blue light material, illustrating the phase morphology of the N2200 polymer and the phase morphology of the small molecule thermal exciton blue light material.

[0030] The molecular structure of the thermal exciton blue light-emitting material is as follows: .

[0031] Table 1: Performance parameters of organic photodetectors

[0032] It can be seen that the organic photodetectors prepared by using the electron transport layer process of polymer N2200 doped with small molecule thermal exciton blue light material (i.e., the organic photodetectors prepared in Examples 2-7) have a larger Jph, a smaller Jdark, and improved EQE and D* compared to the organic photodetectors prepared in Example 1 without doping treatment. This is because when polymer N2200 is doped, a layer is formed after spin coating, such as... Figure 2The bulk heterojunction (BHJ) structure shown enhances the hole-blocking capability of the thermally excited blue light material under reverse bias due to its lower HOMO level, while the shallow LUMO level of the thermally excited blue light material blocks electrons in the dark state, further reducing the dark current of the organic photodetector. The BHJ structure can be effectively formed by preparing the PM6:Y12 active layer using a conventional spin-coating process, thereby enhancing the charge dissociation and transport capabilities within the active layer. Furthermore, this process improves the interfacial contact between the active layer and the cathode / anode transport layers, promoting the formation of ohmic contacts, reducing interfacial contact resistance, and further improving the charge transport efficiency between functional layers, ultimately achieving a comprehensive improvement in all performance parameters of the organic photodetector.

[0033] 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. An organic photodetector based on polymer N2200 doped with small molecules, characterized in that, This organic photodetector adopts an inverted structure, with the following layers from bottom to top: substrate, transparent conductive cathode ITO, poly(N2200) doped thermal exciton blue light material as electron transport layer, PM6:Y12 active layer, MoO3 hole transport layer, and metal anode; the poly(N2200) doped thermal exciton blue light material serves as the electron transport layer, and the polymer N2200 and the thermal exciton blue light material are wet-sprayed onto the ITO layer.

2. The organic photodetector based on polymer N2200 doped small molecules according to claim 1, characterized in that, The electron transport layer is made of N2200:PPIAn2N-CH3, N2200:PPIAn2N-CN, N2200:PPIAn2N-F, N2200:PyIAn1N, N2200:PyIAn2N and N2200:PyIAnp, with a thickness ranging from 20 to 50 nm.

3. The organic photodetector based on polymer N2200 doped small molecules according to claim 2, characterized in that, The molecular structure of the thermal exciton blue light-emitting material is as follows: 。 4. The organic photodetector based on polymer N2200 doped small molecules according to claim 1, characterized in that, The PM6:Y12 active layer is prepared by a mixed solution of electron donor material PM6 and acceptor non-fullerene material Y12, with a thickness ranging from 50 to 300 nm. The mass percentage of PM6:Y12 in the mixed solution is 1:1 to 1:2, and the concentration of the mixed solution is 6 to 15 mg / ml.

5. The organic photodetector based on polymer N2200 doped small molecules according to claim 1, characterized in that, The metal anode is made of Ag, and the thickness of the thin layer ranges from 80 to 100 nm.

6. The organic photodetector based on polymer N2200 doped small molecules according to claim 1, characterized in that, The substrate material is glass or a transparent polymer material, wherein the transparent polymer material is one or more of polyethylene, polymethyl methacrylate, polycarbonate, polyurethane, polyimide, vinyl chloride resin or polyacrylic acid.

7. A method for preparing an organic photodetector based on polymer N2200 doped small molecules as described in any one of claims 1-6, characterized in that, Includes the following steps: The substrate, which consists of a transparent substrate and a transparent conductive cathode ITO, is cleaned and then dried with nitrogen gas. Electron transport layers N2200:PPIAn2N-CH3, N2200:PPIAn2N-CN, N2200:PPIAn2N-F, N2200:PyIAn1N, N2200:PyIAn2N and N2200:PyIAnp were spin-coated, printed or sprayed onto the surface of a transparent conductive cathode ITO, and then thermally annealed. The PM6:Y12 active layer was prepared by spin coating and then annealed. At a vacuum degree of 3×10 -3 Under Pa conditions, MoO3 was vapor-deposited on the surface of the active layer to prepare a hole transport layer; At a vacuum degree of 3×10 -4 Metal anodes are deposited by vapor deposition under Pa conditions.

8. The method for fabricating an organic photodetector based on polymer N2200 doped small molecules according to claim 7, characterized in that, The thermal annealing temperature range for the electron transport layer is 200–250 °C, and the time range is 1–2 h.

9. The method for fabricating an organic photodetector based on polymer N2200 doped small molecules according to claim 7, characterized in that, Hot annealing employs one or more of the following methods: constant temperature hot table heating, oven heating, far-infrared heating, and hot air heating.

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