Multi-pixel organic flexible transparent near-infrared image sensor and method of making the same

Abstract

The present disclosure provides a multi-pixel organic flexible transparent near-infrared image sensor and a preparation method thereof, which comprises: a Ti3C2T x MXene interdigital electrode array; a RAN film covering the Ti3C2T x MXene interdigital electrode array; wherein the Ti3C2T x MXene interdigital electrode array and the RAN film form a van der Waals organic-inorganic heterojunction and hydrogen bond, so that the two are in close contact. The sensor can realize multi-pixel image sensing, and the flexible and transparent characteristics greatly widen the application range of the device. After thousands of bending cycles, the device only normally fluctuates in a small range, and has good mechanical properties.

Description

Technical Field

[0001] This disclosure relates to the field of flexible electronic device technology, and in particular to a multi-pixel organic flexible transparent near-infrared image sensor and its fabrication method. Background Technology

[0002] Ultra-high pixel flexible image sensors have a wide range of applications in biomedicine, visual simulation, human vision restoration and treatment due to their numerous advantages such as portability, wearability and ability to display high-resolution patterns.

[0003] Currently, the electrodes of flexible image sensors are generally gold electrodes. However, because gold electrodes are composed of gold particles, their surfaces are relatively rough and lack dangling bonds, resulting in a relatively small contact area between the gold electrode and the photosensitive material of the flexible image sensor. This leads to a decrease in the performance of the flexible image sensor. Therefore, it is necessary to develop a flexible near-infrared photodetector array with high transparency as an image sensor to further expand its application range and meet practical needs. Summary of the Invention

[0004] In view of the above problems, the present invention provides a multi-pixel organic flexible transparent near-infrared image sensor and its fabrication method, which can optimize the problems existing in the current flexible image sensor.

[0005] One aspect of this disclosure provides a multi-pixel organic flexible transparent near-infrared image sensor, comprising: Ti3C2T x MXene interdigitated electrode array; RAN thin film, covering the Ti3C2T x On the MXene interdigitated electrode array; wherein, the Ti3C2T x The MXene interdigitated electrode array forms a van der Waals organic-inorganic heterojunction and hydrogen bonds with the RAN thin film, resulting in close contact between the two.

[0006] According to embodiments of this disclosure, the Ti3C2T x The MXene interdigitated electrode array has an electrode density greater than 80 electrodes per square centimeter. According to embodiments of this disclosure, the Ti3C2T... x The MXene interdigitated electrode array has an electrode transparency of 70%-85%.

[0007] According to embodiments of this disclosure, the thickness of the multi-pixel organic flexible transparent near-infrared image sensor is no greater than 3 μm.

[0008] Another aspect of this disclosure provides a method for fabricating a multi-pixel organic flexible transparent near-infrared image sensor, comprising: cleaning a flexible substrate; photolithographically forming an interdigitated electrode array pattern on the flexible substrate; and fabricating a Ti3C2T... xMXene material is spin-coated onto the flexible substrate, dried, and then the formed Ti3C2T is formed. x MXene interdigitated electrode array stripping; RAN material spin-coating onto the Ti3C2T x After drying, a multi-pixel organic flexible transparent near-infrared image sensor is obtained on the MXene interdigitated electrode array.

[0009] According to an embodiment of this disclosure, cleaning the flexible substrate includes: sequentially ultrasonically cleaning the flexible substrate with ethanol and deionized water for 10 minutes.

[0010] According to embodiments of this disclosure, the Ti3C2T x MXene material is spin-coated onto the flexible substrate, dried, and then the formed Ti3C2T is formed. x MXene interdigitated electrode array stripping includes:

[0011] The Ti3C2T was stripped in acetone solution. x MXene interdigitated electrode array.

[0012] The above-described at least one technical solution adopted in the embodiments of this disclosure can achieve the following beneficial effects:

[0013] (1)Use Ti3C2T x The -OH groups on the surface of MXene can form additional hydrogen bonds while forming van der Waals organic-inorganic heterojunctions with RAN, making the contact between the two more compact and thus improving the photoresponse of the device.

[0014] (2) Based on the good flexibility and light transmittance of RAN, the RAN film can be uniformly covered in the electrode area. The uniformity and continuity of the RAN film makes it possible for the sensor to achieve multi-pixel imaging.

[0015] (3) The substrate and materials with good flexibility enable the device to maintain relatively stable performance after continuous bending cycles, and have good bendability.

[0016] (4) The preparation time for the electrodes of this sensor is shorter than that for gold electrodes, the operation is simpler, and the material cost is lower.

[0017] (5) The multi-pixel organic flexible transparent near-infrared image sensor provided in this disclosure, its Ti3C2T x MXene interdigitated electrodes have higher transparency than gold electrodes, which can broaden their application range. Attached Figure Description

[0018] To gain a more complete understanding of this disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, wherein:

[0019] Figure 1 The illustration shows a schematic diagram of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure;

[0020] Figure 2A This illustration schematically shows a comparison of the on / off ratios of a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector provided in an embodiment of this disclosure.

[0021] Figure 2B This illustration schematically shows a dynamic cyclic comparison of the on / off ratio of a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector provided in an embodiment of this disclosure.

[0022] Figure 2C This illustration schematically shows a comparison of the on / off ratio of a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector provided in an embodiment of this disclosure as a function of different optical power densities.

[0023] Figure 3A This illustration schematically shows an IT test curve diagram of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure;

[0024] Figure 3B This illustration schematically shows a test curve of photocurrent and dark current variation of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of this disclosure;

[0025] Figure 4 The illustration shows an imaging schematic of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure. Detailed Implementation

[0026] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0029] Figure 1 The illustration shows a schematic diagram of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure.

[0030] like Figure 1 As shown, the multi-pixel organic flexible transparent near-infrared image sensor provided in this embodiment includes: Ti3C2T x MXene interdigitated electrode array 2; RAN thin film 3, covering the Ti3C2T x On MXene interdigitated electrode array 2.

[0031] Due to Ti3C2T x The MXene surface has -OH groups, which can form a van der Waals organic-inorganic heterojunction between itself and the RAN film 3, while forming additional hydrogen bonds to make the two contacts close together, thereby improving the photoresponse of the device.

[0032] Randomized RAN (Randomized RAN) is a novel organic flexible material with good flexibility, light transmittance, and uniform continuity. Applying RAN to flexible image sensors can solve problems such as inhomogeneous photosensitive materials, the inability to fabricate device arrays on a large scale, poor device mechanical properties, and low array transparency. RAN also possesses near-infrared photosensitive properties. When RAN is excited by light, the absorption of photons causes a change in carrier concentration, forming non-equilibrium carriers, which leads to a change in the material's conductivity, i.e., the photoconductive effect. Ti3C2T can be prepared using RAN. x The surface film 3 of the MXene interdigitated electrode array has RAN active material uniformly covering each pixel, and the choice of electrode material and substrate greatly improves the transparency of the device, making it possible to realize multi-pixel imaging.

[0033] According to an embodiment of this disclosure, a multi-pixel organic flexible transparent near-infrared image sensor, namely the Ti3C2T... xThe MXene interdigitated electrode array 2 has an electrode density of more than 80 per square centimeter, an electrode transparency of 70%-85%, and a thickness of no more than 3μm.

[0034] The multi-pixel organic flexible transparent near-infrared image sensor provided in this disclosure embodiment is based on Ti3C2T. x The MXene electrode is composed of stacked two-dimensional nanosheets, which has a larger and smoother surface compared to gold electrodes, making Ti3C2T… x The van der Waals forces between the MXene electrode and the RAN film are stronger, and Ti3C2T x The MXene surface possesses functional groups, which may allow it to form additional bonds with RAN materials, further enhancing the contact between the two, thereby enabling the Ti3C2T-based materials to achieve better performance. x The photodetector composed of MXene electrodes and RAN thin films exhibits superior performance. This sensor also possesses excellent flexibility, allowing the device to maintain relatively stable performance even after repeated bending cycles, providing new avenues for development in biomimetic vision and wearable precision image sensing. Furthermore, due to the properties of Ti3C2T… x The MXene electrode has high transparency, which allows for a wider range of applications for this image sensor.

[0035] This disclosure provides a method for fabricating a multi-pixel organic flexible transparent near-infrared image sensor, including steps S100 to S400.

[0036] S100, cleaning flexible substrate.

[0037] In this embodiment of the disclosure, the flexible substrate ( Figure 1 The structure indicated in Figure 1 is polyethylene terephthalate (PET) material, and the flexible substrate is ultrasonically cleaned with ethanol and deionized water for 10 minutes in sequence.

[0038] S200, an interdigitated electrode array pattern is formed on the flexible substrate by photolithography.

[0039] Using semiconductor microfabrication processes, including spin coating, hardening, exposure, and development, a photolithographic interdigitated electrode array pattern is formed on a prepared PET substrate.

[0040] S300, Ti3C2T x MXene material is spin-coated onto the flexible substrate, dried, and then the formed Ti3C2T is formed. x MXene interdigitated electrode array stripping.

[0041] Highly conductive two-dimensional Ti3C2T with abundant surface functional groups xMXene material was spin-coated onto a photolithographically etched PET substrate. After evaporating the moisture in a vacuum drying oven, the device was exfoliated in acetone to fabricate a flexible, transparent Ti3C2T. x MXene electrode array.

[0042] S400, spin-coating RAN material onto the Ti3C2T x After drying, a multi-pixel organic flexible transparent near-infrared image sensor is obtained on the MXene interdigitated electrode array.

[0043] The organic compound RAN, which has good flexibility and light transmittance, was purified by distillation and then spin-coated onto a flexible transparent Ti3C2T substrate. x The MXene electrode array is then vacuum dried again to achieve uniform film formation over a large area.

[0044] The RAN material can be prepared by the following method, including steps S010 to S050.

[0045] S010, 4,8-bis(5-bromo-4-(2-octyldodecyl)thiophen-2-yl)-112,312-benzo[1,2-c:4,5-c′]bis([1,2,5]thiadiazole), (4,4′-bis(octoxy)-[2,2′-bithiophene]-5,5′-diyl)bis(trimethylstanane) and 2,5-bis(trimethylstanyl)tellurene are dissolved in chlorobenzene.

[0046] After bubbling with nitrogen for 15 minutes, add Pd2(dba)3 and P(o-tol)3 to the solution. Reflux the solution for 2 days; the color changes from blue to brown.

[0047] SO30, after the solution has been cooled to room temperature, methanol is added.

[0048] S040, the precipitate was collected by filtration and purified by Soxhlet extraction using acetone, n-hexane, tetrahydrofuran and chloroform in sequence.

[0049] S050, the chloroform portion is concentrated and then precipitated with methanol.

[0050] Repeat steps S040 to S050 to collect the RAN precipitate and dry it in a vacuum drying oven to obtain RAN solid powder.

[0051] Based on the above method, the preparation time for the sensor electrode is shorter, the operation is simpler, and the material cost is lower than that for preparing a gold electrode.

[0052] Example 1

[0053] Figures 2A-2CA schematic diagram showing a performance comparison between a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector is presented.

[0054] Figure 2A The illustration shows a comparison of the on / off ratios of a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector provided in an embodiment of this disclosure.

[0055] like Figure 2A As shown, the wavelength and optical power density are 915nm (57.3mW / cm²). 2 ), 1064nm (159mW / cm) 2 ), 1122nm (15.6mW / cm) 2 When irradiated with three laser beams, both devices responded, but the Ti3C2T... x -RAN photodetectors have a higher on / off ratio than Au-RAN photodetectors at different wavelengths. In particular, under 1064nm laser irradiation, the on / off ratio of the two can reach 6.25 times.

[0056] Figure 2B The illustration schematically shows a dynamic cyclic comparison of the on / off ratio of a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector provided in an embodiment of the present disclosure.

[0057] like Figure 2B As shown, under laser irradiation at wavelengths of 915 nm, 1064 nm, and 1122 nm, Ti3C2T x MXene electrode photodetectors and gold electrode photodetectors, under the same photosensitive material RAN, Ti3C2T x -RAN photodetectors have a higher on / off ratio in the near-infrared region.

[0058] Figure 2C The illustration shows a comparison of the on / off ratio of a multi-pixel organic flexible transparent near-infrared image sensor and a gold electrode photodetector provided in an embodiment of the present disclosure as a function of different light power densities.

[0059] like Figure 2C As shown in the figure, the on / off ratio of the two devices varies with different optical power densities under laser irradiation at a wavelength of 1064 nm. The figure shows that regardless of the electrode type, the on / off ratio of the devices decreases as the optical power density decreases, but the on / off ratio of Ti3C2T... x The on / off ratio of the -RAN photodetector is still greater than that of the Au-RAN photodetector at different optical power densities.

[0060] Example 2

[0061] Good transparency, portability, and excellent electrical stability after bending and repeated bending deformation are important factors in broadening the application fields of photodetectors. Figures 3A-3B The verification of Ti3C2T is shown. x -Test results of these performance characteristics of the RAN photodetector.

[0062] Figure 3A The illustration shows a schematic diagram of the IT test curve of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure.

[0063] like Figure 3A As shown, by changing the distance between the two ends of the 1D translation stage, the device was bent at 0°, 30°, 60°, 90°, 120°, and 150°, and the Ti3C2T was measured. x The IT curve of the -RAN photodetector shows that the photocurrent and dark current values ​​fluctuate normally within a very small range after bending, which indicates that the Ti3C2T x -RAN photodetectors have good reliability and mechanical flexibility.

[0064] Figure 3B The illustration shows a schematic diagram of the photocurrent and dark current variation test curves of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure.

[0065] like Figure 3B As shown, if Ti3C2T x - A bend in the RAN photodetector is defined as the bending of the detector from 0° to 120° and back to 0°. The photocurrent and dark current values ​​are recorded after every 50 bends. The device underwent a total of 5000 bends. After 5000 cycles, the device fluctuates only within an extremely small range, thus exhibiting attractive flexibility, bend resistance and stability.

[0066] Example 3

[0067] The experiment fabricated 50×50 Ti3C2T on a PET substrate with dimensions of 4cm×4cm. x - RAN photodetector array, to output the pattern, regionally selected 1024 pixels (32×32) from the device array and integrated into the flexible image sensor. Using 1064nm (159mW / cm²)... 2 The laser is used to irradiate the pixel, and the dark current and photocurrent at 0.1V are recorded for each pixel. The ratio of these two values ​​is used as a detection signal.

[0068] Figure 4 The illustration shows an imaging schematic of a multi-pixel organic flexible transparent near-infrared image sensor provided in an embodiment of the present disclosure.

[0069] like Figure 4 As shown, the thousands of pixels make the image clearer, and the deer pattern more vivid, lifelike, and delicate. The excellent imaging capabilities of the Ti3C2T demonstrate its superior performance. x -RAN image sensors have superior sensing capabilities.

[0070] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0071] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of this disclosure should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents.

Claims

1. A multi-pixel organic flexible transparent near-infrared image sensor, characterized in that, include: Ti3C2T x MXene interdigitated electrode array; RAN film, covering the Ti3C2T x On the MXene interdigitated electrode array; Among them, the Ti3C2T x The MXene interdigitated electrode array forms a van der Waals organic-inorganic heterojunction and hydrogen bonds with the RAN thin film, resulting in close contact between the two.

2. The multi-pixel organic flexible transparent near-infrared image sensor according to claim 1, characterized in that, The Ti3C2T x The MXene interdigitated electrode array has an electrode density of more than 80 per square centimeter.

3. The multi-pixel organic flexible transparent near-infrared image sensor according to claim 1, characterized in that, The Ti3C2T x The MXene interdigitated electrode array has an electrode transparency of 70%-85%.

4. The multi-pixel organic flexible transparent near-infrared image sensor according to claim 1, characterized in that, The thickness of the multi-pixel organic flexible transparent near-infrared image sensor is no greater than 3μm.

5. A method for fabricating a multi-pixel organic flexible transparent near-infrared image sensor, characterized in that, include: Cleaning the flexible substrate; An interdigitated electrode array pattern is formed on the flexible substrate by photolithography. Ti3C2T x MXene material is spin-coated onto the flexible substrate, dried, and then the formed Ti3C2T is formed. x MXene interdigitated electrode array stripping; RAN material was spin-coated onto the Ti3C2T x After drying, a multi-pixel organic flexible transparent near-infrared image sensor is obtained on the MXene interdigitated electrode array.

6. The method according to claim 5, characterized in that, The cleaning flexible substrate includes: The flexible substrate was ultrasonically cleaned with ethanol and deionized water for 10 minutes in sequence.

7. The method according to claim 5, characterized in that, The Ti3C2T x MXene material is spin-coated onto the flexible substrate, dried, and then the formed Ti3C2T is formed. x MXene interdigitated electrode array stripping includes: The Ti3C2T was stripped in acetone solution. x MXene interdigitated electrode array.

Images