NIR-OPDs with Hybrid Pseudoplanar / Bulk Heterojunction Structures, Preparation Methods Thereof, and Applications

Abstract

The present invention discloses a NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure, its preparation method and application, relating to the technical field of organic semiconductor thin film photodetectors. Specifically, a novel hybrid pseudo-plane / bulk heterojunction structure is adopted, that is, an N2200 layer is introduced between the cathode of the device and the bulk heterojunction (PPhTQ:COTIC-4F) layer. The obtained near-infrared organic photodetector has a high hole injection barrier at the interface between the N2200 layer and the bulk heterojunction layer, and combines the advantages of the planar heterojunction and the bulk heterojunction. On the premise of ensuring the same photocurrent as that of the device with the traditional bulk heterojunction structure, it effectively suppresses the injection of external carriers, achieving the dual effects of reducing the dark current without losing the photocurrent response, thereby enhancing the effective detection of weak near-infrared light signals by the organic photodetector. In addition, the near-infrared organic photodetector with a hybrid heterojunction structure exhibits excellent performance in alcohol concentration detection and can quickly quantify the alcohol content in the mixed solution with an accuracy of 2%.

Description

Technical Field

[0001] The present invention specifically relates to a NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure, a preparation method and an application thereof. The NIR-OPD can effectively suppress dark current without loss of photocurrent response, and belongs to the technical field of organic semiconductor thin film photodetectors. Background Art

[0002] Near-infrared organic photodetectors (NIR-OPDs) have inherent advantages such as light weight, low cost, tunable detection wavelength, biocompatibility, and the ability to operate at room temperature. They can be well used in the production of wearable, flexible, and cost-effective optoelectronic sensors, thus becoming promising candidates for future electronic products. As an important criterion for evaluating the performance of OPDs, the magnitude of the dark current density affects some key performance parameters of OPDs, such as detectivity, signal-to-noise ratio, and linear dynamic range. Therefore, a low dark current density is crucial for OPDs. OPDs usually adopt a bulk-heterojunction (BHJ) structure to improve their external quantum efficiency and responsivity. However, since both donor and acceptor components coexist near the metal interface of the BHJ structure, the injection of charges from the metal contact under an external bias is very serious. The existence of this charge injection phenomenon directly leads to a high dark current density in the device, and this charge injection phenomenon is more prominent for NIR-OPDs based on narrow-bandgap materials. Therefore, there is an urgent need to explore suitable methods to effectively reduce the dark current density of NIR-OPDs. Currently, some technical means have been adopted to effectively reduce the dark current of the device to a certain extent. In 2021, the research group of Xiaozhang Zhu introduced a method to suppress the dark current by adjusting the thickness of the active layer film in "Carbon-Bridged 1,2-Bis(2-thienyl)ethylene: An Extremely Electron Rich Dithiophene Building Block Enabling Electron Acceptors with Absorption above 1000nm for Highly Sensitive NIR Photodetectors" published in "Journal of the American Chemical Society". However, due to the increase in charge recombination loss, the increase in the thickness of the active layer has an adverse effect on the external quantum efficiency. In 2021, the research group of Huayan Pu pointed out in "Transfer-Printed Nanoscale Poly(3-hexylthiophene-2,5-diyl) Layers for Organic Photodetectors" published in "ACS Applied NanoMaterials" that the transfer printing of an electron blocking layer P3HT between the active layer and the electrode effectively suppressed the dark current density under reverse bias. However, this method increases the hole transport barrier between the active layer and the electron blocking layer, resulting in a lower photocurrent.In the same year, the research group of Zhou Yinhua published "Water Transfer Printing of Multilayered Near-Infrared Organic Photodetectors" in "Advanced Optical Materials", which proposed multilayered NIR-OPDs fabricated by the water transfer printing process, achieving a very significant low dark current density. However, this multilayer structure led to inefficient separation of photo-generated excitons, resulting in a significant reduction in responsivity. Obviously, the existing technologies for reducing dark current density have all suffered from unsatisfactory photocurrent or reduced responsivity, which limits the further development of NIR-OPDs. Summary of the Invention

[0003] In view of the problems existing in the above-mentioned background technology, the present invention provides a NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure, a preparation method and an application thereof. The dark current of the NIR-OPD is reduced by nearly two orders of magnitude, and the photocurrent equivalent to that of traditional NIR-OPDs is maintained, thereby improving the detectivity of the NIR-OPD.

[0004] The present invention provides the following technical solutions:

[0005] A NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure, comprising a glass substrate, a transparent conductive cathode, an electron transport layer, an active layer, a hole transport layer and an anode electrode arranged in sequence from bottom to top. It is characterized in that the active layer is a hybrid pseudo-plane / bulk heterojunction layer composed of a receptor layer and a bulk heterojunction layer in sequence, and the NIR-OPD can effectively suppress dark current without losing the photo-response current.

[0006] Furthermore, the transparent conductive cathode is ITO with a thickness of 120-180 nm; the electron transport layer is ZnO; the active layer is a N2200 receptor layer and a PPhTQ:COTIC-4F bulk heterojunction layer in sequence; the hole transport layer is MoO3; the anode electrode is Ag. Among them, the receptor layer is a polymer receptor material N2200 with a deep occupied molecular orbital energy level and high electron mobility, and the bulk heterojunction layer is a blend of a polymer donor PPhTQ with an ultra-narrow bandgap and a non-fullerene acceptor COTIC-4F. The solvent of the receptor layer N2200 solution is chlorobenzene, and the solvent of the bulk heterojunction layer material solution is chloroform. The swelling effect of the chloroform solvent on N2200 enables a small amount of the bulk heterojunction layer material to vertically penetrate into the N2200 film, forming a novel pseudo-plane / bulk heterojunction structure.

[0007] A preparation method of a NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure, characterized by comprising the following steps:

[0008] Step 1: Clean the surface of the ITO-coated glass substrate, and perform ultrasonic and ultraviolet treatments.

[0009] Step 2: Prepare a ZnO electron transport layer on the ITO surface treated in Step 1.

[0010] Step 3: Prepare a solution of the N2200 acceptor layer material, and spin-coat it on the ZnO electron transport layer to obtain an N2200 acceptor layer.

[0011] Step 4: Prepare a solution of the PPhTQ:COTIC-4F bulk heterojunction layer material, and spin-coat it on the N2200 acceptor layer obtained in Step 3 to obtain a bulk heterojunction layer. The mixed-type pseudo-plane / bulk heterojunction layer composed of the N2200 acceptor layer and the PPhTQ:COTIC-4F bulk heterojunction layer together constitutes the active layer.

[0012] Step 5: Prepare a hole transport layer MoO3 and an anode electrode Ag on the surface of the active layer obtained in Step 4 to obtain NIR-OPDs.

[0013] An application of NIR-OPDs with a mixed-type pseudo-plane / bulk heterojunction structure, characterized in that the NIR-OPDs are used in an alcohol testing device to quickly and accurately quantify the alcohol concentration in a mixture within an accuracy of 2%.

[0014] Further, the alcohol testing device includes a near-infrared laser, a quartz cuvette, NIR-OPDs, a K2400 digital source meter, and a computer. Different concentrations of alcohol and different alcohol contents of wine are contained in the quartz cuvette. The near-infrared laser of the alcohol testing device irradiates through the quartz cuvette onto the NIR-OPDs, and the corresponding photocurrent response signal is read by the K2400 digital source meter and the computer.

[0015] Advantages of the present invention:

[0016] 1. The present invention proposes a method for effectively suppressing the dark current of NIR-OPDs without losing the light response. By adopting a novel mixed-type pseudo-plane / bulk heterojunction structure, the acceptor layer and the bulk heterojunction layer are spin-coated in sequence. Utilizing the deep energy level of the acceptor layer N2200, the charge injection barrier is effectively increased. By using the swelling effect of chloroform solvent on N2200, a small amount of the bulk heterojunction layer material vertically penetrates into the N2200 thin film, forming a novel pseudo-plane / bulk heterojunction structure, achieving the effect of suppressing the dark current and realizing a reduction of nearly two orders of magnitude. At the same time, by integrating the advantages of planar heterojunction and bulk heterojunction, the high photocurrent of the device is maintained, and finally, the performance far superior to that of traditional bulk heterojunction NIR-OPDs is realized.

[0017] 2. The NIR-OPDs prepared by using the novel hybrid pseudo-plane / bulk heterojunction structure proposed by the present invention can quickly and accurately quantify the alcohol concentration in the mixture. With a simple and small test device, the alcohol concentration can be quickly detected within an accuracy of 2% according to the magnitude of the photocurrent response of the NIR-OPDs. Compared with the traditional spectrometer analysis method, this method reduces the complexity of the equipment and the manufacturing cost, and has great application potential in small portable devices.

[0018] 3. The preparation process of the present invention is simple and easy to implement, without adding additional processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of NIR-OPDs based on the traditional bulk heterojunction structure in the prior art;

[0020] Figure 2 is a schematic structural diagram of the NIR-OPDs of the present invention that can effectively suppress dark current without losing light response;

[0021] Figure 3 are the photocurrent and dark current curves of the NIR-OPDs of Example 1 and the comparative example of the present invention;

[0022] Figure 4 is a comparative curve graph of the external quantum efficiency of the NIR-OPDs of Example 1 and the comparative example of the present invention;

[0023] Figure 5 is a comparative curve graph of the responsivity of the NIR-OPDs of Example 1 and the comparative example of the present invention;

[0024] Figure 6 is a comparative curve graph of the detectivity of the NIR-OPDs of Example 1 and the comparative example of the present invention under a bias voltage of -0.2V;

[0025] Figure 7 is a comparative curve graph of the response speed of the NIR-OPDs of Example 1 and the comparative example of the present invention under a bias voltage of -0.2V;

[0026] Figure 8 is the in-situ grazing incidence wide-angle X-ray scattering (GIWAXS) test pattern of the NIR-OPDs of Example 1 and the comparative example of the present invention; wherein, (a) is the 2D-GIWAXS test pattern of the comparative example, (b) is the 2D-GIWAXS pattern test pattern of Example 1, and (c) is the line cutting curves of the comparative example and Example 1 in the in-plane and out-of-plane directions of the GIWAXS test pattern;

[0027] Figure 9Schematic diagram and physical diagram of the alcohol testing device of NIR-OPDs proposed in Embodiment 1 of the present invention. Among them, (a) is the schematic diagram of the alcohol testing device, and (b) is the physical diagram of the alcohol testing device;

[0028] Figure 10 Graph of the alcohol content test results of the test sample by NIR-OPDs proposed in Embodiment 1 of the present invention; among them, the asterisk, dot, and triangle respectively represent Snow Beer, Chinese Jinjiu, and Hongxing Erguotou. Detailed implementation manners

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described below in conjunction with the following specific embodiments and additional figures.

[0030] Embodiment 1

[0031] Embodiment 1 of the present invention proposes a NIR-OPD with a hybrid pseudo-planar / bulk heterojunction structure, which can effectively suppress dark current without loss of light response. Its structure is as Figure 2 shown, including a glass substrate, an ITO cathode electrode, a ZnO electron transport layer, an N2200 acceptor layer, a PPhTQ:COTIC-4F bulk heterojunction layer, a MoO3 hole transport layer, and an Ag anode electrode, which are sequentially arranged from bottom to top.

[0032] A preparation method of a NIR-OPD with a hybrid pseudo-planar / bulk heterojunction structure includes the following steps:

[0033] Step 1: Rub the glass substrate coated with the ITO electrode with a cleaning agent and rinse it with ultrapure water. The rinsed glass substrate is ultrasonically cleaned multiple times with ultrapure water, anhydrous ethanol, acetone, and anhydrous ethanol in sequence, and then the surface of the cleaned glass substrate is subjected to ultraviolet treatment for 15 minutes;

[0034] Step 2: Prepare a ZnO electron transport layer precursor solution, spin-coat the ZnO precursor solution on the surface of the glass substrate treated in Step 1 at a speed of 5000 rpm for 30 s, and then perform thermal annealing at 200 °C in air for 1 hour to finally form a ZnO electron transport layer;

[0035] Step 3: Prepare an N2200 acceptor layer material solution with a concentration of 4 mg / mL and a solvent of chlorobenzene. After stirring at 60 °C on a magnetic stirring table for more than 6 hours, spin-coat it on the ZnO electron transport layer obtained in Step 2 at a speed of 5000 rpm for 30 s to obtain an N2200 acceptor layer;

[0036] Step 4: Prepare the PPhTQ:COTIC-4F bulk heterojunction layer material solution. PPhTQ and COTIC-4F are mixed at a mass ratio of 1:1.5. The donor concentration of the mixed material is 12 mg / mL, and the solvent is chloroform:2% chloronaphthalene. After stirring at room temperature on a magnetic stirrer for more than 6 hours, spin-coat it on the N2200 acceptor layer obtained in Step 3 at a speed of 4000 rpm for 30 s to obtain the bulk heterojunction layer. The N2200 acceptor layer and the PPhTQ:COTIC-4F bulk heterojunction layer together constitute the active layer;

[0037] Step 5: Place the substrate with the active layer obtained in Step 4 in the evaporation chamber of an organic vapor deposition system for the evaporation of the MoO3 hole transport layer and the Ag anode electrode. The thickness of the MoO3 hole transport layer is 10 nm, and the thickness of the Ag anode electrode is 100 nm. Finally, NIR-OPDs that effectively suppress dark current without loss of optical response are obtained.

[0038] Comparative Example

[0039] This comparative example is used as a comparison with Example 1, and a NIR-OPD with a traditional bulk heterojunction structure is proposed. The device structure is as Figure 1 shown, including a glass substrate, an ITO cathode electrode, a ZnO electron transport layer, a PPhTQ:COTIC-4F bulk heterojunction layer, a MoO3 hole transport layer, and an Ag anode electrode.

[0040] The preparation method of the NIR-OPD with the traditional bulk heterojunction structure proposed in this comparative example includes the following steps:

[0041] Step 1: Rub the glass substrate coated with the ITO electrode with a cleaning agent and rinse it with ultrapure water. The rinsed glass substrate is ultrasonically cleaned multiple times with ultrapure water, absolute ethanol, acetone, and absolute ethanol in sequence, and then the surface of the cleaned glass substrate is subjected to ultraviolet treatment for 15 minutes;

[0042] Step 2: Prepare the ZnO electron transport layer precursor solution. Spin-coat the ZnO precursor solution on the surface of the glass substrate treated in Step 1 at a speed of 5000 rpm for 30 s, and then perform thermal annealing at 200 °C in air for 1 hour to finally form the ZnO electron transport layer;

[0043] Step 3: Prepare the PPhTQ:COTIC-4F bulk heterojunction layer material solution. PPhTQ and COTIC-4F are mixed at a mass ratio of 1:1.5. The donor concentration of the mixed material is 12 mg / mL, and the solvent is chloroform:2% chloronaphthalene. After stirring at room temperature on a magnetic stirrer for more than 6 hours, spin-coat it on the ZnO electron transport layer obtained in Step 2 at a speed of 4000 rpm for 30 s to obtain the active layer;

[0044] Step 4: Place the substrate with the active layer obtained in Step 3 into the evaporation chamber of an organic vapor deposition system for the evaporation of the MoO3 hole transport layer and the Ag anode electrode. The thickness of the MoO3 hole transport layer is 10 nm, and the thickness of the Ag anode electrode is 100 nm. Finally, NIR-OPDs with a traditional bulk heterojunction structure are obtained.

[0045] In this invention, the NIR-OPDs obtained in Example 1 and the comparative example are respectively subjected to optoelectronic tests to obtain the dark current and photocurrent in the near-infrared at the 1310 nm band as shown in Figure 3 . It can be seen that compared with the NIR-OPDs with a traditional bulk heterojunction structure, the NIR-OPDs based on the hybrid pseudo-plane / bulk heterojunction structure have a significantly reduced dark current, reaching nearly two orders of magnitude, from 10 -5 reduced to 10 -8 A / cm 2 .

[0046] From Figure 4 the external quantum efficiency graph as shown, it can be seen that at a bias voltage of -0.2 V, the external quantum efficiency of the NIR-OPDs based on the hybrid pseudo-plane / bulk heterojunction structure is 5.61% at 1400 nm, and the external quantum efficiency of the NIR-OPDs with a traditional bulk heterojunction structure is 1.98%. The hybrid pseudo-plane / bulk heterojunction structure ensures a high external quantum efficiency of the device.

[0047] From Figure 5 the responsivity graph as shown, it can be seen that at a bias voltage of -0.2 V, the responsivity of the NIR-OPDs based on the hybrid pseudo-plane / bulk heterojunction structure is 22.41 mA / W at 1400 nm; the external quantum efficiency of the NIR-OPDs with a traditional bulk heterojunction structure is 63.34 mA / W. The hybrid pseudo-plane / bulk heterojunction structure ensures a high responsivity of the device.

[0048] From Figure 6 the detectivity comparison curve as shown, it can be seen that at an external bias voltage of -0.2 V, the NIR-OPDs based on the hybrid pseudo-plane / bulk heterojunction structure have a higher detectivity, and the detectivity at the 1400 nm band reaches 10 11 Jones.

[0049] From Figure 7 the response time comparison curve as shown, it can be seen that at an external bias voltage of -0.2 V, the NIR-OPDs based on the hybrid pseudo-plane / bulk heterojunction structure have a faster response speed. The rise time and fall time at the 1400 nm band are 7.66 and 7.72 μs respectively, while the rise time and fall time of the NIR-OPDs with a traditional bulk heterojunction structure are 9.41 and 9.43 μs respectively.

[0050] From Figure 8 The comparison results of the grazing-incidence wide-angle X-ray scattering (GIWAXS) test of synchrotron radiation shown in Figure 8 indicate that the hybrid pseudo-plane / bulk heterojunction film has a smaller stacking spacing, indicating that the hybrid pseudo-plane / bulk heterojunction film has a tighter, more uniform molecular stacking structure and a more stable morphology; the hybrid pseudo-plane / bulk heterojunction film also has a larger coherent length (CCL) value, which means that the hybrid pseudo-plane / bulk heterojunction film has a higher crystallinity, which is helpful for charge transport.

[0051] Example 2

[0052] Example 2 of the present invention proposes the practical application of NIR-OPDs containing a hybrid pseudo-plane / bulk heterojunction structure in alcohol concentration detection. The test device is as shown in Figure 9 . From left to right, there are a 1310 nm laser, a quartz cuvette, and NIR-OPDs in sequence. The 1310 nm light passes through the quartz cuvette and irradiates on the NIR-OPDs. To ensure the stability and accuracy of the test results, the device is placed on an optical platform and detected in the dark. The test principle is to utilize the difference in the absorption of light with a wavelength greater than 1200 nm by water and alcohol, resulting in the difference in the photocurrent response of NIR-OPDs. Figure 9 shown, from left to right are a 1310 nm laser, a quartz cuvette, and NIR-OPDs in sequence. The 1310 nm light passes through the quartz cuvette and irradiates on the NIR-OPDs. To ensure the stability and accuracy of the test results, the device is placed on an optical platform and detected in the dark. The test principle is to utilize the difference in the absorption of light with a wavelength greater than 1200 nm by water and alcohol, resulting in the difference in the photocurrent response of NIR-OPDs.

[0053] The application of the NIR-OPDs proposed in Example 2 of the present invention, which effectively suppresses dark current without loss of light response, in alcohol concentration detection includes the following steps:

[0054] Step 1: Prepare NIR-OPDs based on a hybrid pseudo-plane / bulk heterojunction structure, and the preparation method is the same as that in Example 1;

[0055] Step 2: Prepare calibration samples for establishing a detection model: Mix anhydrous ethanol with an alcohol content ≥ 99.7% with ultrapure water, convert it into alcohol concentration according to the volume ratio, and increase the alcohol content from 0% to 99.7% in increments of 10% to obtain 11 calibration samples, and place them in a sealed quartz cuvette;

[0056] Step 3: Prepare three different types of test samples with different alcohol contents, such as Snow Beer, Chinese Jinjiu, and Hongxing Erguotou, and place them in a sealed quartz cuvette. These test samples will be used to evaluate the detection accuracy of the alcohol concentration detection device described in Example 2;

[0057] Step 4: Set up a test device as shown in Figure 9 , randomly and repeatedly irradiate the 11 calibration samples with a 1310 nm laser onto the NIR-OPDs to obtain the corresponding photocurrent responses. Process these photocurrent responses to obtain the calibration curve with error bars shown in Figure 10 ; Figure 9 shown, randomly and repeatedly irradiate the 11 calibration samples with a 1310 nm laser onto the NIR-OPDs to obtain the corresponding photocurrent responses. Process these photocurrent responses to obtain the calibration curve with error bars shown in Figure 10 ; Figure 10 shown calibration curve with error bars;

[0058] Step 5: Randomly and repeatedly pass the 1310 nm laser through the test samples of Snow Beer, Chinese Spirits, and Red Star Erguotou to obtain the corresponding photocurrent responses. Process these photocurrent responses, and predict the alcohol concentrations of the three test samples from the calibration curve with error bars shown in Figure 10 the figure;

[0059] Step 6: Snow Beer, Chinese Spirits, and Red Star Erguotou are represented by asterisks, dots, and triangles respectively in Figure 10 the figure. The measured alcohol content values of Snow Beer, Chinese Spirits, and Red Star Erguotou are 3.15% vol, 35.56% vol, and 56.39% vol respectively. The errors compared with the manufacturer's values (≥3.6% vol, 35% vol, and 56% vol respectively) are 12.5%, 1.6%, and 0.69%.

[0060] Compared with the manufacturer's values, the measured values of Chinese Spirits and Red Star Erguotou are reliable with smaller errors, while the measured value of the Snow Beer sample is lower with a larger error. This is mainly because the carbon dioxide bubbles in the beer have a certain scattering effect on light, resulting in a reduction of the transmitted light. Therefore, the alcohol concentration test device based on NIR-OPDs that effectively suppresses dark current without losing light response achieves rapid detection of alcohol concentration within 2% accuracy. Compared with traditional spectrometer analysis, this method reduces the complexity and manufacturing cost of the device and has great application potential in small portable devices.

[0061] Although the present application has been described above with reference to specific embodiments, those skilled in the art should understand that many modifications can be made to the configurations and details disclosed in the present application within the principles and scope of the present application. The protection scope of the present application is determined by the appended claims, and the claims are intended to cover all modifications included in the literal meaning or scope of the equivalents of the technical features in the claims.

[0062] It should be noted that although the above steps are described in a specific order, it does not mean that the steps must be executed in the above specific order. In fact, some of these steps can be executed concurrently or even in a different order, as long as the required functions can be achieved.

[0063] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to technologies in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure, comprising a glass substrate, a transparent conductive cathode, an electron transport layer, an active layer, a hole transport layer, and an anode electrode sequentially arranged from bottom to top, characterized in that, The active layer is a hybrid pseudo-plane / bulk heterojunction layer composed of a receptor layer and a bulk heterojunction layer in sequence. The NIR-OPDs can effectively suppress dark current without loss of photocurrent response. The transparent conductive cathode is ITO with a thickness of 120 - 180 nm. The electron transport layer is ZnO. The active layer is a N2200 receptor layer and a PPhTQ:COTIC-4F bulk heterojunction layer in sequence. The hole transport layer is MoO3. The anode electrode is Ag.

2. The preparation method of an NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure according to claim 1, characterized in that, It includes the following steps: Step 1: Clean the surface of the glass substrate coated with ITO, and perform ultrasonic and ultraviolet treatments. Step 2: Prepare a ZnO electron transport layer on the ITO surface treated in Step 1. Step 3: Prepare a solution of the N2200 receptor layer material, and spin-coat it on the ZnO electron transport layer to obtain the N2200 receptor layer. Step 4: Prepare a solution of the PPhTQ:COTIC-4F bulk heterojunction layer material using chloroform as the solvent, and spin-coat it on the N2200 receptor layer obtained in Step 3 to obtain the bulk heterojunction layer. The hybrid pseudo-plane / bulk heterojunction layer composed of the N2200 receptor layer and the PPhTQ:COTIC-4F bulk heterojunction layer together constitutes the active layer. Step 5: Prepare a hole transport layer MoO3 and an anode electrode Ag on the active layer surface obtained in Step 4 to obtain NIR-OPDs.

3. The preparation method of an NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure according to claim 2, wherein, Step 1 includes: Rub the glass substrate coated with the ITO electrode using a cleaning agent, and rinse it with ultrapure water. The rinsed glass substrate is ultrasonically cleaned multiple times successively with ultrapure water, absolute ethanol, acetone, and absolute ethanol, and then the surface of the cleaned glass substrate is subjected to a 15-minute ultraviolet treatment.

4. The preparation method of a NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure according to claim 2, characterized in that, Step 2 includes: Prepare a ZnO electron transport layer precursor solution, spin-coat the ZnO precursor solution on the glass substrate coated with ITO treated in Step 1 at a speed of 5000 rpm for 30 s, and then perform thermal annealing at 200 °C in air for 1 hour to finally form the ZnO electron transport layer.

5. The preparation method of a NIR-OPD with a hybrid pseudo-planar / bulk heterojunction structure according to claim 2, wherein, Step 3 includes: Prepare a solution of the N2200 receptor layer material with a concentration of 4 mg / mL and chlorobenzene as the solvent. After stirring on a magnetic stirring table at 60 °C for more than 6 hours, spin-coat it on the ZnO electron transport layer obtained in Step 2 at a speed of 5000 rpm for 30 s to obtain the N2200 receptor layer.

6. The preparation method of a NIR-OPD with a hybrid pseudo-plane / bulk heterojunction structure according to claim 2, characterized in that, Step 4 includes: Prepare a solution of the PPhTQ:COTIC-4F bulk heterojunction layer material. PPhTQ and COTIC-4F are mixed in a mass ratio of 1:1.5, and the donor concentration of the mixed material is 12 mg / mL. The solvent is chloroform:2% vol chloronaphthalene. After stirring on a magnetic stirring table at room temperature for more than 6 hours, continue to spin-coat it on the N2200 receptor layer obtained in Step 3 at a speed of 4000 rpm for 30 s to obtain the bulk heterojunction layer. The N2200 receptor layer and the bulk heterojunction layer together constitute the active layer.

7. The preparation method of a NIR-OPD with a hybrid pseudo-planar / bulk heterojunction structure according to claim 2, characterized in that, Step 5 includes: placing the substrate with the active layer obtained in Step 4 into the evaporation chamber of an organic vapor deposition system for evaporating the MoO3 hole transport layer and the Ag anode electrode, where the thickness of the MoO3 hole transport layer is 10 nm and the thickness of the Ag anode electrode is 100 nm, and finally obtaining NIR-OPDs that can effectively suppress dark current without losing photo-response.

8. Use of a NIR-OPD comprising a hybrid pseudo-planar / bulk heterojunction structure according to claim 1, characterized in that, The NIR-OPDs are used in an alcohol testing device to quickly and accurately quantify the alcohol concentration in a mixture within an accuracy of 2%.

9. Use of a NIR-OPD having a hybrid pseudo-plane / bulk heterojunction structure according to claim 8, characterized in that The alcohol testing device includes a near-infrared laser, a quartz cuvette, NIR-OPDs, a K2400 digital source meter, and a computer. Different concentrations of alcohol and liquors with different alcohol contents are placed in the quartz cuvette. The near-infrared laser of the alcohol testing device irradiates through the quartz cuvette into the NIR-OPDs, and the corresponding photocurrent response signals are read by the K2400 digital source meter and the computer.

Images