Photoelectric detector with electron transport layer terminated by free radical scavenger and preparation method of photoelectric detector

Abstract

The invention discloses a photoelectric detector with an electron transport layer terminated by a free radical scavenger and a preparation method, and relates to the field of organic photoelectric detectors, the photoelectric detector adopts an inverted structure and comprises a substrate, a transparent conductive cathode ITO, an electron transport layer, an active layer, a hole transport layer and a metal anode, the upper layer of the ITO is spin-coated with terminated ZnO of the free radical scavenger through a wet method, and the upper layer of the ITO is spin-coated with the active layer. Wherein the oxygen vacancy passivation effectively reduces the trap state density, inhibits the non-radiative recombination process of charges, improves the photoelectric conversion efficiency, reduces the dark current, improves the signal-to-noise ratio and improves the detection sensitivity, and the free radical capture significantly reduces the degradation of the photoelectric material under long-time work; the active layer is prepared through the spin coating technology, the bulk heterojunction structure is formed on the active layer, the charge dissociation and transmission capacity in the active layer is improved, the contact between the active layer and the electrode transmission layer is improved, ohmic contact is promoted, the contact resistance formed between interfaces is reduced, and the charge transmission capacity between different functional layers is improved. And the high-performance organic photoelectric detector is realized.

Description

Technical Field

[0001] This invention relates to the field of organic photodetectors, and more specifically to a photodetector with a free radical scavenger-terminated electron transport layer and its preparation method. Background Technology

[0002] Organic photodetectors (OPDs), as an emerging type of photoelectric conversion device, have attracted much attention in recent years due to their unique advantages in fields such as flexible electronics, biomedical sensing, environmental monitoring, and optical communication. Compared with traditional inorganic semiconductor photodetectors, organic photodetectors have significant advantages such as solution-processability, thinness and flexibility, large-area manufacturing capability, and tunable spectral response, opening up broad prospects for applications in next-generation electronic devices.

[0003] Early devices were limited by the performance of organic semiconductor materials, resulting in significant limitations in photoelectric conversion efficiency, stability, and device lifetime. However, with the rapid development of high-performance organic semiconductor materials, the performance of organic photodetectors has been significantly improved. Furthermore, the introduction of perovskite and quantum dot materials has further broadened the spectral response range of the devices, enhancing detection sensitivity and response speed.

[0004] In terms of device structure, organic photodetectors have evolved from single-layer structures to double-layer heterojunctions, planar heterojunctions, and vertical heterojunctions, significantly improving carrier separation and transport efficiency. Simultaneously, the introduction of micro / nano structures and photonic crystals has significantly enhanced the light-harvesting capability of the devices, improving photoelectric conversion efficiency and signal-to-noise ratio. Flexible and wearable electronic devices are one of the important application areas of organic photodetectors. Due to the excellent flexibility and processability of organic semiconductor materials, these devices can be integrated onto flexible substrates and maintain stable performance under significant bending and stretching conditions, providing technical support for wearable health monitoring devices. For example, organic photodetectors can 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. In the field of environmental monitoring, organic photodetectors also show great potential. For example, ultraviolet and infrared light detection technologies can be applied to air quality monitoring and water quality detection, helping to improve environmental management. In the field of optical communication, organic photodetectors play a key role in high-speed optoelectronic transmission systems due to their fast response and low power consumption characteristics.

[0005] Despite significant advancements in the performance of organic photodetectors, challenges remain in areas such as device stability, dark current suppression, long-term lifespan, and large-area uniformity. Future development will focus on developing novel high-performance organic semiconductor materials, optimizing device structure design, reducing dark current, and improving photoelectric conversion efficiency and stability. Furthermore, the deep integration of organic photodetectors with artificial intelligence and the Internet of Things (IoT) will further broaden their application areas, promoting their widespread use in smart healthcare, environmental monitoring, flexible displays, and human-computer interaction. With continuous breakthroughs in materials science, device fabrication, and system integration technologies, organic photodetectors will play an increasingly important role in future high-performance optoelectronic systems, driving the development of next-generation optoelectronic technologies and bringing more possibilities for innovation in optoelectronic technology. Summary of the Invention

[0006] The problem this invention aims to solve is: how to provide an organic photodetector based on a free radical scavenger-terminated ZnO as an electron transport layer and its preparation method. This aims to address the issue that the electron transport layer in organic photodetectors cannot reduce the density of trapped states and suppress free radical activity, resulting in high dark current and low signal-to-noise ratio. Furthermore, it can improve electron transport capability, helping to enhance the separation, transport, and interfacial transfer efficiency of photogenerated carriers. Simultaneously, free radical trapping can significantly reduce the degradation of photoelectric materials under long-term operation, extending their lifespan, and ultimately solving the problem of reduced device performance.

[0007] The technical solution of this invention is as follows:

[0008] A photodetector with a free radical scavenger-terminated electron transport layer is described. The photodetector employs an inverted structure, consisting of a substrate, a transparent conductive cathode (ITO), an electron transport layer, an active layer, a MoO3 hole transport layer, and a metal anode, arranged from bottom to top. The free radical scavenger-terminated ZnO serves as the electron transport layer, which is applied to the ITO layer via wet spin-coating. Oxygen vacancy passivation effectively reduces the trapped state density, suppresses non-radiative charge recombination, and improves the device's photoelectric conversion efficiency. It also reduces dark current, improves the signal-to-noise ratio, and enhances detection sensitivity. Furthermore, free radical capture significantly reduces the degradation of photoelectric materials over long-term operation, maintaining the device's long-term stability. The active layer is then prepared using a conventional spin-coating process, forming a bulk heterojunction (BHJ) structure. This enhances the charge dissociation and transport capabilities within the active layer. Improving the contact between the active layer and the electrode transport layer promotes ohmic contact formation, reduces interfacial contact resistance, and further enhances charge transport between different functional layers, ultimately achieving a high-performance organic photodetector.

[0009] Preferably, the electron transport layer material is a mixed solution of BHT@ZnO, BHT-p@ZnO, BHTP@ZnO, BHTPP@ZnO, BHT2P@ZnO, or PyHT@ZnO, with a thickness ranging from 20 to 80 nm; the mass percentage of polymers BHT, BHT-p, BHTP, BHTPP, BHT2P, or PyHT to ZnO in the mixed solution is 1:0.5 to 1:5, and the concentration of the mixed solution is 0.5 to 3 mg / ml.

[0010] Preferably, the active layer is prepared by a mixed solution of electron donor material PM6 and acceptor non-fullerene material Y6-HU, with a thickness ranging from 50 to 300 nm; the mass percentage of PM6:Y6-HU in the mixed solution is 1:1 to 1:2, and the concentration of the mixed solution is 6 to 15 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 and polyacrylic acid.

[0013] This invention also discloses a method for fabricating a photodetector with a free radical scavenger-terminated electron transport layer, the fabrication process comprising the following steps:

[0014] (1) Clean the substrate composed of a transparent substrate and a transparent conductive cathode ITO, and then dry it with nitrogen gas;

[0015] (2) Spin-coating, printing or spraying electron transport layers BHT@ZnO, BHT-p@ZnO, BHTP@ZnO, BHTPP@ZnO, BHT2P@ZnO or PyHT@ZnO on the transparent conductive cathode ITO surface, and then performing thermal annealing;

[0016] (3) The PM6:Y6-HU active layer was prepared by spin coating and then annealed;

[0017] (4) 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;

[0018] (5) At a vacuum degree of 3×10 -4 Metal anodes are deposited by vapor deposition under Pa conditions.

[0019] 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.

[0020] 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.

[0021] The advantages of this invention are:

[0022] 1. By using ZnO capped with free radical scavengers as an electron transport layer, oxygen vacancy passivation can not only effectively reduce the density of trapped states and suppress the nonradiative recombination process of charges, thus improving the photoelectric conversion efficiency of the device, but also reduce dark current, improve signal-to-noise ratio, and increase detection sensitivity. Meanwhile, the capture of free radicals can significantly reduce the degradation of optoelectronic materials under long-term operation and maintain the long-term stability of the device, thereby improving the performance of organic photodetectors.

[0023] 2. By adopting BHJ's inverted organic photodetector system, the capped ZnO of the free radical scavenger is effectively promoted to form ohmic contacts with the lower active layer (electron acceptor Y6-HU part) and the upper active layer (electron donor PM6 part) and the MoO3 anode buffer layer, respectively, thereby reducing the contact resistance between different functional layers and effectively improving the charge transport capability between different functional layers.

[0024] 3. Free radical scavengers are easy to synthesize, low in cost, and easy to process. They also have good dispersibility with ZnO, ultimately forming ZnO ink with free radical scavengers. This ink has excellent smoothness and easier processing, ensuring that the ZnO with free radical scavengers in the electron transport layer has very good contact with the lower active layer, effectively improving electron transport capability and enhancing the performance of organic photodetectors. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the photodetector with the free radical scavenger-terminated electron transport layer of the present invention;

[0026] Figure 2 This is a schematic diagram of the phase distribution of the ZnO electron transport layer using a free radical scavenger in this invention;

[0027] Figure 3 It is the chemical formula of BHT in Example 2;

[0028] Figure 4 It is the chemical formula of BHT-p in Example 3;

[0029] Figure 5 It is the chemical formula of BHTP in Example 4;

[0030] Figure 6 It is the chemical formula of BHTPP in Example 5;

[0031] Figure 7 It is the chemical formula of PyHT in Example 6;

[0032] The figures are labeled as follows: 1-substrate, 2-transparent conductive cathode ITO, 3-electron transport layer, 4-active layer, 5-MoO3 anode buffer layer, 6-metal anode. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Example 1 (Control Group):

[0035] 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.

[0036] 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 (160 ℃, 30 min).

[0037] 3. A PM6:Y6-HU (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).

[0038] 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition;

[0039] 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer;

[0040] 6. Under standard test conditions: the photocurrent density (J) of the device at AM 1.5 G was measured. ph The value is 2.45 × 10⁻⁶. -2 A / cm 2 Dark current density (J) dark The value is 8.52 × 10. -7 A / cm 2 The external quantum efficiency (EQE) is 78.31%, and the detectivity (D*) is 2.53 × 10⁻⁶. 11 Jones, with a response (R) of 0.308 A / W.

[0041] Example 2:

[0042] 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.

[0043] 2. A BHT@ZnO solution (0.05 g BHT dissolved in ZnO solution) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared using a spin-coating process (5000 rpm, 50 s, 40 nm), and the resulting film was then subjected to thermal annealing (200 ℃, 2 h). The chemical formula of BHT is as follows: Figure 3 As shown;

[0044] 3. A PM6:Y6-HU (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).

[0045] 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition;

[0046] 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer;

[0047] 6. Under standard test conditions: the photocurrent density (J) of the device at AM 1.5 G was measured. ph The value is 3.76 × 10. -2 A / cm 2 Dark current density (J) dark The value is 1.36 × 10⁻⁶. -8 A / cm 2 The external quantum efficiency (EQE) is 83.35%, and the detectivity (D*) is 6.63 × 10⁻⁶. 12 Jones, with a response (R) of 0.334 A / W.

[0048] Example 3:

[0049] 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.

[0050] 2. A BHT-p@ZnO solution (0.05 g BHT-p dissolved in ZnO solution) was spin-coated onto the surface of a transparent conductive ITO cathode. An electron transport layer was prepared using a spin-coating process (5000 rpm, 50 s, 40 nm), and the resulting film was then subjected to thermal annealing (200 ℃, 2 h). The chemical formula of BHT-p is as follows: Figure 4 As shown;

[0051] 3. A PM6:Y6-HU (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).

[0052] 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition;

[0053] 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer;

[0054] 6. Under standard test conditions: the photocurrent density (J) of the device at AM 1.5 G was measured. ph The value is 3.51 × 10⁻⁶. -2 A / cm 2 Dark current density (J) dark 4.53×10 -8 A / cm 2 The external quantum efficiency (EQE) is 82.03%, and the detectivity (D*) is 3.62 × 10⁻⁶. 12 Jones, with a response rate (R) of 0.321 A / W.

[0055] Example 4:

[0056] 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.

[0057] 2. A BHTP@ZnO solution (0.05 g BHTP dissolved in ZnO solution) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared using a spin-coating process (5000 rpm, 50 s, 40 nm), and the resulting film was then subjected to thermal annealing (200 ℃, 2 h). The chemical formula of BHTP is as follows: Figure 5 As shown;

[0058] 3. A PM6:Y6-HU (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).

[0059] 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition;

[0060] 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer;

[0061] 6. Under standard test conditions: the photocurrent density (J) of the device at AM 1.5 G was measured. ph The value is 3.36 × 10. -2 A / cm 2 Dark current density (J) dark The value is 7.65 × 10. -8 A / cm 2 The external quantum efficiency (EQE) is 81.75%, and the detectivity (D*) is 2.64 × 10⁻⁶. 12 Jones, with a response (R) of 0.315 A / W.

[0062] Example 5:

[0063] 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.

[0064] 2. A BHTPP@ZnO solution (0.05 g BHTPP dissolved in ZnO solution) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared using a spin-coating process (5000 rpm, 50 s, 40 nm), and the resulting film was then subjected to thermal annealing (200 ℃, 2 h). The chemical formula of BHTPP is as follows: Figure 6 As shown;

[0065] 3. A PM6:Y6-HU (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).

[0066] 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition;

[0067] 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer;

[0068] 6. Under standard test conditions: the photocurrent density (J) of the device at AM 1.5 G was measured. ph The value is 2.65 × 10⁻⁶. -2 A / cm 2 Dark current density (J) dark The value is 7.81 × 10⁻⁶. -7 A / cm 2The external quantum efficiency (EQE) is 79.04%, and the detectivity (D*) is 4.05 × 10⁻⁶. 11 Jones, with a response rate (R) of 0.313 A / W.

[0069] Example 6:

[0070] 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.

[0071] 2. A PyHT@ZnO solution (0.05 g PyHT dissolved in ZnO solution) was spin-coated onto the surface of a transparent conductive cathode ITO. An electron transport layer was prepared using a spin-coating process (5000 rpm, 50 s, 40 nm), and the resulting film was then subjected to thermal annealing (200 ℃, 2 h). The chemical formula of PyHT is as follows: Figure 7 As shown;

[0072] 3. A PM6:Y6-HU (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).

[0073] 4. A MoO3 (15 nm) anolyte buffer layer is deposited on the active layer by vapor deposition;

[0074] 5. Deposit a metallic anode Ag (100 nm) onto the hole transport layer;

[0075] 6. Under standard test conditions: the photocurrent density (J) of the device at AM 1.5 G was measured. ph The value is 2.78 × 10. -2 A / cm 2 Dark current density (J) dark The value is 6.82 × 10⁻⁶. -7 A / cm 2 The external quantum efficiency (EQE) is 80.27%, and the detectivity (D*) is 6.25 × 10⁻⁶. 11 Jones, with a response (R) of 0.320 A / W.

[0076] Table 1: Performance parameters of organic photodetectors

[0077] <![CDATA[J dark (A / cm 2 )]]> <![CDATA[J ph (A / cm 2 )]]> EQE(%) D*(Jones) R(A / W) Example 1 (Control Group) <![CDATA[8.52×10 -7 ]]> <![CDATA[2.45×10 -2 ]]> 78.31 <![CDATA[2.53×10 11 ]]> 0.308 Example 2 <![CDATA[1.36×10 -8 ]]> <![CDATA[3.76×10 -2 ]]> 83.35 <![CDATA[6.63×10 12 ]]> 0.334 Example 3 <![CDATA[4.53×10 -8 ]]> <![CDATA[3.51×10 -2 ]]> 82.03 <![CDATA[3.62×10 12 ]]> 0.321 Example 4 <![CDATA[7.65×10 -8 ]]> <![CDATA[3.36×10 -2 ]]> 81.75 <![CDATA[2.64×10 12 ]]> 0.315 Example 5 <![CDATA[7.81×10 -7 ]]> <![CDATA[2.65×10 -2 ]]> 79.04 <![CDATA[4.05×10 11 ]]> 0.313 Example 6 <![CDATA[6.82×10 -7 ]]> <![CDATA[2.78×10 -2 ]]> 80.27 <![CDATA[6.25×10 11 ]]> 0.320

[0078] It can be seen that the organic photodetectors prepared by using the free radical scavenger-terminated ZnO electron transport layer process (i.e., the organic photodetectors prepared in Examples 2-6) have a higher J value compared to the organic photodetectors prepared in Example 1 (which do not have a free radical scavenger-terminated ZnO electron transport layer). ph Get bigger, J dark Decreased, while EQE and D* both increased. After treatment with ZnO capped with a free radical scavenger (e.g.) Figure 2 Oxygen vacancy passivation can effectively reduce the density of trapped states, suppress nonradiative recombination of charges, and improve the photoelectric conversion efficiency of the device. It can also reduce dark current, improve signal-to-noise ratio, and increase detection sensitivity. The capture of free radicals can significantly reduce the degradation of optoelectronic materials under long-term operation and maintain the long-term stability of the device. Then, the PM6:Y6-HU active layer is prepared by conventional spin coating process, which can realize the formation of BHJ structure in the active layer, thereby improving the charge dissociation and transport capability in the active layer. By improving the contact between the active layer and the electrode transport layer, it promotes the formation of ohmic contact, reduces the contact resistance formed between the interface, and further improves the charge transport capability between different functional layers, ultimately realizing a high-performance organic photodetector.

[0079] 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 photodetector with a free radical scavenger-terminated electron transport layer, characterized in that, The photodetector adopts an inverted structure, consisting of a substrate, a transparent conductive cathode ITO, an electron transport layer, an active layer, a MoO3 hole transport layer, and a metal anode from bottom to top. The electron transport layer is ZnO capped with a free radical scavenger, which is applied to the ITO layer by wet spin coating. Oxygen vacancy passivation not only effectively reduces the trapped state density and suppresses the nonradiative recombination process of charges, thus improving the photoelectric conversion efficiency of the device, but also reduces dark current, improves the signal-to-noise ratio, and enhances detection sensitivity. Meanwhile, the capture of free radicals can significantly reduce the degradation of photoelectric materials under long-term operation and maintain the long-term stability of the device. The active layer is then prepared using a conventional spin-coating process, which enables the formation of a bulk heterojunction (BHJ) structure in the active layer. This improves the charge dissociation and transport capabilities within the active layer. Furthermore, by improving the contact between the active layer and the electrode transport layer, ohmic contact is formed, reducing the contact resistance between the interfaces. This further enhances the charge transport capabilities between different functional layers, ultimately achieving a high-performance organic photodetector.

2. The photodetector with a free radical scavenger-terminated electron transport layer according to claim 1, characterized in that, The electron transport layer material is a mixed solution of BHT@ZnO, BHT-p@ZnO, BHTP@ZnO, BHTPP@ZnO, BHT2P@ZnO, or PyHT@ZnO, with a thickness ranging from 20 to 80 nm; the mass percentage of polymers BHT, BHT-p, BHTP, BHTPP, BHT2P, or PyHT to ZnO in the mixed solution is 1:0.5 to 1:5, and the concentration of the mixed solution is 0.5 to 3 mg / ml.

3. The photodetector with a free radical scavenger-terminated electron transport layer according to claim 1, characterized in that, The active layer is prepared by a mixed solution of electron donor material PM6 and acceptor non-fullerene material Y6-HU, with a thickness ranging from 50 to 300 nm; the mass percentage of PM6:Y6-HU in the mixed solution is 1:1 to 1:2, and the concentration of the mixed solution is 6 to 15 mg / ml.

4. The photodetector with a free radical scavenger-terminated electron transport layer 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 photodetector with a free radical scavenger-terminated electron transport layer 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 preparation method for preparing a photodetector with a free radical scavenger-terminated electron transport layer 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 electron transport layers BHT@ZnO, BHT-p@ZnO, BHTP@ZnO, BHTPP@ZnO, BHT2P@ZnO or PyHT@ZnO on the transparent conductive cathode ITO surface, and then performing thermal annealing. (3) The PM6:Y6-HU active layer was prepared by spin coating and then annealed; (4) 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; (5) At a vacuum degree of 3×10 -4 Metal anodes are deposited by vapor deposition under Pa conditions.

7. The preparation method 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 preparation method 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.

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