Curved surface photoelectric detector array and preparation method thereof

Abstract

The invention relates to the technical field of photoelectric detectors, and discloses a curved surface photoelectric detector array and a preparation method thereof. The preparation method comprises the following steps: depositing an indium tin oxide film on a substrate to obtain an ITO substrate; performing array type patterning processing on the ITO substrate, and controlling the pixel size, the pixel spacing and the array scale to obtain a first element; sequentially spin-coating a hole transport layer, a photosensitive active layer and an electron transport layer deposition electrode on the first element to obtain a planar flexible detector array; casting a liquid prepolymer, and curing the liquid prepolymer on the hemispherical glass lens to obtain a prepolymer shell; transferring the planar flexible detector array to the inner wall of the prepolymer shell, and forming a curved surface detector array on the inner wall of the prepolymer shell; and coating the adhesive on the other hemispherical glass lens, transferring the curved surface detector array to the hemispherical glass lens, and removing the prepolymer shell to finish the preparation. The problems that the number of pixels is small, the bending radius is large and the field angle is small in an existing curved surface detector are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of curved surface photoelectric detector preparation, and in particular to a curved surface photoelectric detector array and a preparation method thereof. Background Art

[0002] In the field of photoelectric detector preparation, curvature is the frontier point in the development of the fourth-generation photoelectric detection technology. The curved structure can not only simplify the optical system and reduce costs, but also compensate for the optical aberration of the photosensitive surface to improve detection and recognition capabilities. It has important applications in national defense science and technology, medical equipment, aerospace and other fields.

[0003] The use of soft lithography and transfer methods can realize the preparation of curved surface detection systems, but it will also increase the difficulty of the integration process and sacrifice the size of each pixel, making it difficult to achieve high-density imaging units.

[0004] Since commercial charge-coupled devices and complementary metal oxide semiconductor photodetectors are limited by mainstream planar micromachining processes and traditional semiconductor materials, such as silicon, indium gallium arsenide, type-II superlattice and mercury cadmium telluride, etc. Due to the intrinsic mechanical brittleness and thermal expansion coefficient of these materials, although the thinning method can effectively prepare curved detectors, the curvature and field of view of the device are sacrificed, and the device size is large. There are obvious defects in the existing curved detectors, such as a small number of pixels, a large bending radius and a small field of view. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of small number of pixels, large bending radius and small field of view in existing curved detectors, and to provide a curved photoelectric detector array with a large number of pixels, small bending radius and large field of view, and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a curved photodetector array, comprising the following steps:

[0008] Providing a substrate, and depositing an indium tin oxide thin film on the substrate to obtain an ITO substrate;

[0009] Performing array-type patterning on the ITO substrate, controlling the pixel size, pixel spacing and array scale to obtain a first element;

[0010] A hole transport layer, a photosensitive active layer and an electron transport layer are sequentially spin-coated on the first element, and then electrodes are deposited to obtain a planar flexible detector array;

[0011] Providing a liquid prepolymer and a hemispherical glass lens, and casting and curing the liquid prepolymer on the hemispherical glass lens to obtain a prepolymer shell;

[0012] transferring the planar flexible detector array onto the inner wall of the prepolymer shell, and forming a curved detector array on the inner wall of the prepolymer shell;

[0013] Adhesive is applied to another hemispherical glass lens, the curved detector array is transferred to the hemispherical glass lens, and the prepolymer shell is removed to complete the preparation.

[0014] Optionally, the indium tin oxide film has a thickness of 80 nm and a surface resistance of 30 Ω / sq.

[0015] Optionally, the array patterning process includes photoresist deposition, ultraviolet exposure, wet etching, stripping cleaning and ozone treatment.

[0016] Optionally, the pixel size, pixel pitch and array scale are 50 μm, 40 μm and 128×128 respectively.

[0017] Optionally, the hole transport layer is a poly 2,3-dihydrothieno-1,4-dioxin-polystyrene sulfonate solution; the photosensitive active layer is a cesium lead iodine solution; and the electron transport layer is a block copolymer and a carbon 60 solution.

[0018] Optionally, the electrode thickness is 100 nm.

[0019] Optionally, the liquid prepolymer is polydimethylsiloxane.

[0020] Optionally, the adhesive is a UV adhesive.

[0021] Optionally, the specific operation of forming the curved detector array on the inner wall of the prepolymer shell is to transfer the planar flexible detector array to the inner wall of the prepolymer shell, release the stress and assist with pneumatic means to form the curved detector array.

[0022] In a second aspect, the present invention further provides a curved photodetector array, which is prepared by the above-mentioned preparation method.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. The present invention innovatively proposes a method for preparing a curved photodetector array. First, standard photolithography technology is used to control the pixel size, pixel spacing and array scale. Secondly, pneumatic transfer technology is used to prepare the curved detector array. Such a setting can, on the one hand, form a high-density pixel readout circuit on a flexible substrate. On the other hand, it can also use pneumatic means to accurately control the generation of external stress, thereby avoiding device failure due to excessively rapid stress changes, thereby forming a high-density curved detector array. The method for preparing a curved photodetector array provided by the present invention can effectively solve the problems of a small number of pixels, a large bending radius and a small field of view in the current curved detectors. The prepared device has excellent light response characteristics and good light response stability, and can meet the detection needs in a bent state.

[0025] 2. The curved photodetector array provided by the present invention has excellent performance, a wide range of applications and high superiority. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the preparation method of the curved photodetector array of the present invention.

[0027] Figure 2 Schematic diagram of the current-voltage curve of the curved detector array 1 prepared in Example 1 of the present invention.

[0028] Figure 3 Schematic diagram of the photocurrent test curve of the curved detector array 1 prepared in Example 1 of the present invention.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. DETAILED DESCRIPTION

[0031] In the prior art, the soft lithography and transfer methods can realize the preparation of curved surface detection systems, but at the same time, it will increase the difficulty of the integrated process and sacrifice the size of each pixel, making it difficult to achieve a high-density imaging unit. Since commercial charge-coupled devices and complementary metal oxide semiconductor photodetectors are limited by mainstream planar micromachining processes and the intrinsic mechanical brittleness and thermal expansion coefficient of traditional semiconductor materials (such as silicon, indium gallium arsenide, type II superlattice and mercury cadmium telluride, etc.), although the thinning method can effectively prepare curved surface detectors, it sacrifices the curvature and field of view of the device, and the device size is large, which has obvious defects.

[0032] See also Figure 1 The first embodiment of the present invention provides a method for preparing a curved photodetector array, comprising the following steps:

[0033] Providing a substrate, and depositing an indium tin oxide thin film on the substrate to obtain an ITO substrate;

[0034] Performing array-type patterning on the ITO substrate, controlling the pixel size, pixel spacing and array scale to obtain a first element;

[0035] A hole transport layer, a photosensitive active layer and an electron transport layer are sequentially spin-coated on the first element, and then electrodes are deposited to obtain a planar flexible detector array;

[0036] Providing a liquid prepolymer and a hemispherical glass lens, and casting and curing the liquid prepolymer on the hemispherical glass lens to obtain a prepolymer shell;

[0037] transferring the planar flexible detector array onto the inner wall of the prepolymer shell, and forming a curved detector array on the inner wall of the prepolymer shell;

[0038] Adhesive is applied to another hemispherical glass lens, the curved detector array is transferred to the hemispherical glass lens, and the prepolymer shell is removed to complete the preparation.

[0039] It can be understood that the method for preparing a curved photodetector array in this embodiment uses standard photolithography technology to control pixel size, pixel spacing and array scale, and uses pneumatic transfer technology to prepare the curved detector array. On the one hand, it can form a high-density pixel readout circuit on a flexible substrate, and on the other hand, it can use pneumatic means to accurately control the generation of external stress to avoid device failure due to rapid stress changes, thereby forming a high-density curved detector array, which effectively solves the problems of small number of pixels and insufficient curvature in current curved detectors.

[0040] In some embodiments of the present invention, the substrate is preferably a flexible substrate, such as a PET substrate.

[0041] Specifically, in some embodiments, the substrate is pretreated, and the specific operation of the pretreatment is to immerse the substrate in a surfactant, deionized water and isopropanol solution in sequence, and perform ultrasonic cleaning, and each cleaning time is 15 minutes.

[0042] In some embodiments of the present invention, the thickness of the indium tin oxide film is 80 nm and the surface resistance is 30Ω / sq.

[0043] In some embodiments of the present invention, a magnetron sputtering method is used to deposit an indium tin oxide thin film on a substrate.

[0044] In some embodiments of the present invention, the array patterning process includes photoresist deposition, ultraviolet exposure, wet etching, stripping cleaning and ozone treatment.

[0045] In some embodiments of the present invention, the pixel size, pixel pitch and array scale are 50 μm, 40 μm and 128×128 respectively.

[0046] It should be understood that by controlling the pixel size, pixel pitch and array scale, a readout circuit for high-density pixels can be formed on a flexible substrate.

[0047] In some embodiments of the present invention, the hole transport layer is a poly (2,3-dihydrothieno-1,4-dioxin)-polystyrene sulfonate solution; the photosensitive active layer is a cesium lead iodine solution; and the electron transport layer is a block copolymer and a carbon 60 solution.

[0048] Specifically, in one embodiment, a poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrene sulfonate) (PEDOT:PSS) solution (hole transport layer) is spin-coated onto the substrate at a spin-coating speed of 6000 rpm for 30 seconds; an annealing treatment is performed at an annealing temperature of 150° C. for 10 minutes to form a dense PEDOT:PSS hole transport film;

[0049] Cesium lead iodide (CsPbI 3 ) quantum dot solution (photosensitive active layer) was spin-coated onto the substrate at a speed of 3000 rpm for 30 seconds; annealing was performed at a temperature of 100°C for 10 minutes to form a dense CsPbI 3 Photosensitive active films;

[0050] Block copolymer (BCP) and carbon 60 (C60) films were deposited by thermal evaporation with thicknesses of 20 nm and 30 nm, respectively.

[0051] It should be understood that the cesium lead iodine quantum dot material prepared by the solution method is used as the photosensitive active layer of the curved detector array. Its typical organic surface ligand nanointerconnected structure is utilized to improve the overall mechanical flexibility of the device, and can relieve external stress to avoid rapid failure of the device. It can overcome the problem of insufficient curvature of traditional curved detectors due to the fragility of the material itself.

[0052] Furthermore, the preparation method also uses functional layer films prepared by solution method and evaporation method: hole transport layer, photosensitive active layer and electron transport layer, which can be directly deposited on the flexible / rigid readout circuit without using the flip-chip interconnection processing technology of the traditional device array and the readout circuit. On the one hand, it can reduce the preparation cost, and on the other hand, it can ignore the limitation of pixel size caused by the flip-chip interconnection process itself, which is superior.

[0053] In some embodiments of the present invention, the electrode has a thickness of 100 nm.

[0054] Specifically, a thermal evaporation method is used to deposit electrodes to form a planar flexible detector array, preferably gold electrodes.

[0055] In some embodiments of the present invention, the liquid prepolymer is polydimethylsiloxane.

[0056] In some embodiments of the present invention, the adhesive is a UV adhesive.

[0057] In some embodiments of the present invention, the specific operation of forming a curved detector array on the inner wall of the prepolymer shell is to transfer the planar flexible detector array to the inner wall of the prepolymer shell, release stress and assist with pneumatic means to form a curved detector array.

[0058] It should be understood that the use of pneumatic methods can accurately control the generation of external stress and avoid device failure due to rapid stress changes, thereby forming a high-density curved detector array, so that the prepared curved photoelectric detector array has a large number of pixels, a small bending radius, a large field of view, and excellent performance.

[0059] In a second aspect, the present invention further provides a curved photodetector array, which is prepared using the method for preparing the curved photodetector array as described above.

[0060] The curved photodetector array and the method for preparing the curved photodetector array provided in this embodiment have the same beneficial effects, so they will not be described in detail here.

[0061] Example 1

[0062] In this example, see Figure 1 , the specific operations are:

[0063] (1) The flexible substrate (PET) was immersed in a surfactant, deionized water and isopropanol solution in sequence and then ultrasonically cleaned for 15 minutes each time;

[0064] (2) using magnetron sputtering to deposit an indium tin oxide (ITO) thin film on the cleaned PET substrate with a thickness of 80 nm and a surface resistance of 30 Ω / sq;

[0065] (3) performing array patterning on the above-mentioned ITO substrate, the process including photoresist deposition, ultraviolet exposure, wet etching, stripping cleaning and ozone treatment, wherein the pixel size, pixel pitch and array scale are 50 μm, 40 μm and 128×128 respectively;

[0066] (4) spin coating a poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrene sulfonate) (PEDOT:PSS) solution (hole transport layer) onto the substrate at a spin coating speed of 6000 rpm for 30 seconds;

[0067] (5) performing annealing treatment at a temperature of 150° C. for 10 minutes to form a dense PEDOT:PSS hole transport film;

[0068] (6) Cesium lead iodide (CsPbI 3 ) quantum dot solution (photosensitive active layer) is spin-coated onto the above substrate at a spin-coating speed of 3000 rpm for 30 seconds;

[0069] (7) Annealing treatment is performed at a temperature of 100°C and a time of 10 minutes to form a dense CsPbI 3 Photosensitive active films;

[0070] (8) Block copolymer (BCP) and carbon 60 (C 60 ) films were deposited with thicknesses of 20nm and 30nm respectively;

[0071] (9) using thermal evaporation to deposit gold electrodes with a thickness of 100 nm to form a planar flexible detector array;

[0072] (10) a large amount of liquid prepolymer is cast and cured on a hemispherical glass lens (with adjustable radius) to form a spherical elastomeric transfer element in polydimethylsiloxane (PDMS);

[0073] (11) Using a matching custom fixture to fix the lens and provide a raised edge around the PDMS, and providing biaxial tension through the coordinated radial motion of multiple independent paddle arms, the PDMS is stretched into a “drumhead” shape;

[0074] (12) Transferring the planar flexible detector array onto PDMS, while releasing stress and assisting with pneumatic means, to form a curved detector array;

[0075] (13) The array is transferred to a matching hemispherical glass lens coated with UV adhesive, the adhesive is cured and the PDMS is removed to prepare a curved detector array 1.

[0076] Test Example 1

[0077] 1.1 Test operation

[0078] The photoelectric performance of the curved detector array 1 prepared in Example 1 was tested. The typical current-voltage curves of the device in the dark state and under illumination are shown in Figure 2 .

[0079] 1.2 Results Analysis

[0080] See also Figure 2 It can be seen (the vertical axis is Current representing current, and the horizontal axis is Voltage representing voltage) that the light response characteristics of the curved detector array 1 prepared in Example 1 are excellent.

[0081] Test Example 2

[0082] 2.1 Test operation

[0083] The photoelectric performance of the curved detector array 1 prepared in Example 1 was tested at different bending radii. The photocurrent test curve of the device is shown in Figure 3 .

[0084] 2.2 Results Analysis

[0085] See also Figure 2 It can be seen (the vertical axis is Current representing current, and the horizontal axis is Time representing time) that during the bending process, the optical response stability of the device is good and can meet the detection requirements in the bent state.

[0086] In summary, according to the tests of Experimental Examples 1 and 2, the method for preparing a curved photodetector array of the present invention has an excellent performance in preparing a curved detector array, and the response stability is still good in a bent state, which can effectively solve the problems of a small number of pixels and insufficient curvature in the current curved detector.

[0087] The above is a detailed introduction to the preparation method of a curved photodetector array and colloidal quantum dots disclosed in an embodiment of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention. Any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a curved photodetector array, characterized in that: The following steps are involved: Providing a substrate, and depositing an indium tin oxide thin film on the substrate to obtain an ITO substrate; Performing array-type patterning on the ITO substrate, controlling the pixel size, pixel spacing and array scale to obtain a first element; A hole transport layer, a photosensitive active layer and an electron transport layer are sequentially spin-coated on the first element, and then electrodes are deposited to obtain a planar flexible detector array; Providing a liquid prepolymer and a hemispherical glass lens, and casting and curing the liquid prepolymer on the hemispherical glass lens to obtain a prepolymer shell; transferring the planar flexible detector array onto the inner wall of the prepolymer shell, and forming a curved detector array on the inner wall of the prepolymer shell; Adhesive is applied to another hemispherical glass lens, the curved detector array is transferred to the hemispherical glass lens, and the prepolymer shell is removed to complete the preparation.

2. The method for preparing a curved photodetector array according to claim 1, wherein: The thickness of the indium tin oxide film is 80 nm, and the surface resistance is 30 Ω / sq.

3. The method for preparing a curved photodetector array according to claim 1, wherein: The array patterning process includes photoresist deposition, ultraviolet exposure, wet etching, stripping cleaning and ozone treatment.

4. The method for preparing a curved photodetector array according to claim 1, wherein: The pixel size, pixel pitch and array scale are 50 μm, 40 μm and 128×128 respectively.

5. The method for preparing a curved photodetector array according to claim 1, wherein: The hole transport layer is a poly 2,3-dihydrothieno-1,4-dioxin-polystyrene sulfonate solution; the photosensitive active layer is a cesium lead iodine solution; and the electron transport layer is a block copolymer and a carbon 60 solution.

6. The method for preparing a curved photodetector array according to claim 1, characterized in that: The electrode thickness is 100 nm.

7. The method for preparing a curved photodetector array according to claim 1, characterized in that: The liquid prepolymer is polydimethylsiloxane.

8. The method for preparing a curved photodetector array according to claim 1, characterized in that: The adhesive is a UV adhesive.

9. The method for preparing a curved photodetector array according to claim 1, wherein: The specific operation of forming the curved detector array on the inner wall of the prepolymer shell is to transfer the flat flexible detector array to the inner wall of the prepolymer shell, release the stress and assist with pneumatic means to form the curved detector array.

10. A curved photodetector array, characterized in that: The curved photodetector array is prepared by the preparation method described in any one of claims 1 to 9.

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