Photoelectric detector and preparation method thereof

Abstract

The invention relates to a photoelectric detector with an organic material-indium antimonide quantum dot blending as a photoactive layer and a preparation method thereof, and the device structure of the photoelectric detector comprises a metal electrode layer, an electron transport layer, a photosensitive active layer, a hole transport layer and a transparent conductive glass layer from top to bottom in sequence. Wherein the material of the photosensitive active layer is a thin film prepared by blending an organic semiconductor material and indium antimonide (InSb) quantum dots, the indium antimonide quantum dots are used for generating photon-generated carriers, the organic material is used as an external transmission channel of the photon-generated carriers, and the combination of the indium antimonide quantum dots and the organic material effectively improves the charge generation and transfer characteristics, so that the photoelectric conversion efficiency is improved. The novel photoelectric detector formed by the indium antimonide quantum dots is successfully realized on the indium tin oxide transparent conductive glass substrate, the photoelectric detector has high light current response and high response speed, and the wide spectrum response of an infrared band can be realized; the invention further provides a preparation method of the photoelectric detector, the preparation method is simple, raw materials are rich, the device performance is high, and the photoelectric detector has a relatively high application prospect in the field of infrared detection.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric materials and photoelectric detectors, and in particular to a photoelectric detector using an organic material-indium antimonide quantum dot blend as a photoactive layer and a preparation method thereof. Background Art

[0002] Photodetectors (also known as optical sensors) are sensors that convert light signals into electrical signals. Compared to the visible wavelength, the infrared wavelength has garnered significant attention in recent years due to its advantages, including low atmospheric background radiation, high resolution, strong spatial penetration, and relative eye safety.

[0003] However, there are still many urgent issues to be addressed in the development of materials and devices for infrared detection. For example, while materials such as Ge, PbX (X = S, Se, Te), and InGaAs for the near-infrared band offer relatively high cost-performance, issues such as lattice quality, dislocation density, and defect states remain unresolved, as do theoretical limitations of these materials, limiting the potential for further significant performance improvements. Currently, the most mature material systems for the mid-infrared band are epitaxially grown thin-film materials such as HgCdTe and GaSb, but these have high preparation costs, low process yields, and require low-temperature refrigeration for their operation, severely limiting their scope of application.

[0004] Colloidal quantum dots (QDs) generally refer to chemically synthesized nanocrystals with a size between 2 and 20 nm that exhibit quantum confinement. Due to their simple and efficient synthesis, tunable band gap, excellent light absorption properties, simple device integration, and compatibility with highly flexible and highly transparent systems, they hold significant application prospects in the field of photodetectors. Currently, research on mid-infrared photodetection devices using colloidal quantum dots is largely unresolved. Indium antimonide (InSb) is a direct bandgap semiconductor material with a bandgap of 0.17 eV, corresponding to a wavelength of 7.2 μm, covering the near-infrared to mid-infrared range. Furthermore, its large exciton Bohr radius and small exciton binding energy suggest that quantum dots possess excellent size controllability and carrier transport capabilities. Most importantly, InSb has the highest carrier mobility of any known semiconductor material suitable for mid-infrared detection, reaching 78,000 cm² V⁻¹ s⁻¹. These unique and excellent properties are key to the development of high-performance mid-infrared photodetectors. At the same time, indium antimonide colloidal quantum dots have the excellent characteristics of high efficiency in colloidal quantum dot preparation, flexible and adjustable optical properties (quantum effect), and low high-temperature noise current, making them an extremely outstanding candidate for the new generation of infrared photoelectric detection devices.

[0005] At present, although there have been continuous reports on the research on the preparation of InSb2 quantum dots, there are basically no reports on photodetectors based on InSb2 quantum dots. Summary of the Invention

[0006] The first purpose of the present invention is to address the problems in the prior art and provide a photodetector with an organic material-indium antimonide quantum dot blend as a photoactive layer, rationally apply appropriate organic materials to improve the transport characteristics of photogenerated carriers of indium antimonide quantum dots, and improve the performance of the photodetector. At the same time, a preparation method for a photodetector with an organic material-indium antimonide quantum dot blend as a photoactive layer is provided. The preparation method is simple and convenient and is conducive to large-scale industrial production.

[0007] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A photodetector with a photoactive layer made of a blend of organic materials and indium antimonide quantum dots. The device structure consists of, from top to bottom, a metal electrode layer, an electron transport layer, a photoactive layer, a hole transport layer, and a transparent conductive glass layer. The photoactive layer is made of organic semiconductor materials and indium antimonide (InSb) quantum dots. The excellent charge and energy transfer properties of organic molecules are exploited to increase the transmission channels for photogenerated carriers within the quantum dots, thereby enhancing the stability of the quantum dots.

[0009] The photosensitive active layer of the photodetector is a thin film of a mixed solution of organic materials and indium antimonide quantum dots, wherein the organic materials are TFB, C 60 、C 70 , PCBM, Y6, Poly-TPD or more.

[0010] When the organic material is mixed with the indium antimonide quantum dots, the molar ratio of the organic material and the indium antimonide quantum dots is 1 to 3:1.

[0011] Furthermore, the organic material is TFB, and the molar ratio of the TFB to the indium antimonide quantum dots is 1 to 3:1.

[0012] Furthermore, the molar ratio of the organic material to TFB and indium antimonide quantum dots is 2:1.

[0013] When any two combinations of the organic materials are mixed with the indium antimonide quantum dots, the molar ratio of the three is 0.5-1.5:0.5-1.5:1.

[0014] Furthermore, the organic materials are PCBM and Poly-TPD, and the molar ratio of the two organic materials and indium antimonide quantum dots is 0.5-1.5:0.5-1.5:1.

[0015] Furthermore, the organic materials are PCBM and Poly-TPD, and the molar ratio of the two organic materials and indium antimonide quantum dots is 1:1:1.

[0016] The hole transport layer of the photodetector is one of PEDOT:PSS and NiO.

[0017] The electron transport layer is C 60 、C 70 , Y6.

[0018] The metal electrode layer of the photodetector is Ag, Au or Al thin film, and the conductive material of the transparent conductive glass layer is indium tin oxide.

[0019] The substrate thickness of the transparent conductive glass layer is not limited. The thickness of the indium tin oxide film of the transparent conductive glass layer is 30 to 380 nm. The thickness of the hole transport layer is 1 to 30 nm. The thickness of the electron transport layer is 1 to 30 nm. The thickness of the photosensitive active layer is 100 to 200 nm. The thickness of the metal electrode layer is 50 to 100 nm.

[0020] The first object of the present invention is to address the problems in the prior art and provide a method for preparing a photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer. The preparation method comprises the following steps:

[0021] 1) Dust removal and cleaning of indium tin oxide transparent conductive glass;

[0022] 2) preparing a hole transport layer on the clean conductive glass obtained in step 1);

[0023] 3) mixing an organic material and indium antimonide (InSb) quantum dots in a polar organic solution, and forming a thin film of the mixed solution on top of the hole transport layer on the structure obtained in step 2) as a photoactive layer;

[0024] 4) preparing an electron transport layer on the photoactive layer on the structure obtained in step 3);

[0025] 5) Vapor-depositing a metal electrode layer on the multilayer structure obtained in step 4). After the metal electrode layer is evaporated, a photodetector with an organic material-indium antimonide quantum dot blend as a photoactive layer is obtained.

[0026] Furthermore, the dust removal in step 1) can be carried out by using gas blowing, compressed air or electrostatic dust removal methods;

[0027] Furthermore, the cleaning in step 1) can be performed by ultrasonic cleaning using acetone, ethanol, or deionized water, and then dried with nitrogen gas;

[0028] Furthermore, the hole transport layer in step 2) is prepared by solution spin coating process, and the material is PEDOT:PSS or NiO;

[0029] Furthermore, the polar organic solution in step 3) is chlorobenzene, toluene or n-hexane solution.

[0030] Furthermore, the photosensitive active layer in step 3) is a thin film prepared by a spin coating process or a drop coating process of a blended solution, or a spray coating process;

[0031] Furthermore, the preparation of the electron transport layer in step 4) adopts a physical deposition process, which can be magnetron sputtering or atomic layer deposition, and the material is C 60 、C 70 or Y6;

[0032] Furthermore, in the step 5), the metal electrode layer is prepared by an evaporation process, wherein the structure is placed in an evaporation device, the evaporation device is evacuated to a vacuum state, and then the metal electrode layer is evaporated by an evaporation process, wherein the metal electrode layer is an Au, Ag or Al thin film.

[0033] The photodetector of the present invention using an organic material-indium antimonide quantum dot blend as a photoactive layer and its preparation method have the following beneficial effects:

[0034] 1) A photodetector using an organic material-indium antimonide quantum dot blend as the photoactive layer. A mixture of organic material and indium antimonide quantum dots was developed as the light absorption layer. The indium antimonide quantum dots generate photogenerated carriers, while the organic material acts as a channel for the external transmission of photogenerated carriers. The combination of the two effectively improves the charge generation and transfer characteristics. The organic material also plays a protective role, effectively improving the stability of the indium antimonide quantum dots. A new photodetector composed of indium antimonide quantum dots was successfully realized on an indium tin oxide transparent conductive glass substrate. The device has a high photocurrent response, a fast response speed, and can achieve a wide spectral response in the infrared band.

[0035] 2) A method for preparing a photodetector using an organic material-indium antimonide quantum dot blend as the photoactive layer. The photodetector using organic material-indium antimonide quantum dots has the advantages of high device performance and a wide spectral response range in the infrared band. The preparation method is simple, the raw materials are abundant, and the device performance is high. It has great application prospects in the field of infrared detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0037] Figure 1 1 is a schematic cross-sectional view of a multilayer structure of a photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer, prepared in a preparation method according to an embodiment of the present invention;

[0038] Figure 2 This is a flow chart of the preparation method according to an embodiment of the present invention;

[0039] Figure 3 This is a test data graph of the light state and dark state of a photodetector with an organic material-indium antimonide quantum dot blend as a photoactive layer under different bias voltages prepared in the preparation method of an embodiment of the present invention;

[0040] Figure 4 This is a test data chart of the continuous alternation of OFF and ON states of a photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer prepared in the preparation method of an embodiment of the present invention;

[0041] Figure 5 This is a test data graph of the rising and falling edges of the photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer when switching between the OFF state and the ON state, prepared in the preparation method of an embodiment of the present invention;

[0042] Figure 6 This is a comparative test data chart of a photodetector with an organic material-indium antimonide quantum dot blend as a photoactive layer prepared in the preparation method of an embodiment of the present invention and a device without a photosensitive material. DETAILED DESCRIPTION

[0043] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only used as examples and cannot be used to limit the scope of protection of the present invention.

[0044] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0045] The embodiment of the present invention provides a photodetector with an organic material-indium antimonide quantum dot blend as a photoactive layer, the photodetector comprising a metal electrode layer, an electron transport layer, a photosensitive active layer, a hole transport layer, and a transparent conductive glass layer connected in sequence;

[0046] An embodiment of the present invention further provides a method for preparing a photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer, the preparation method comprising the following steps:

[0047] 1) Dust removal and cleaning of indium tin oxide transparent conductive glass;

[0048] 2) preparing a hole transport layer on the clean conductive glass obtained in step 1);

[0049] 3) preparing a thin film of a blend of organic material and InSb quantum dots as a photoactive layer on the hole transport layer on the structure obtained in step 2);

[0050] 4) preparing an electron transport layer on the photoactive layer on the structure obtained in step 3);

[0051] 5) Vapor-depositing a metal electrode layer on the multilayer structure prepared in step 4).

[0052] The technical solution of the present invention is further described in detail below through specific embodiments.

[0053] Example 1

[0054] This embodiment is a method for preparing a photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer, the preparation method comprising the following steps:

[0055] Step 1: Use nitrogen to purge and remove dust from the indium tin oxide transparent conductive glass until there is no obvious impurity dust;

[0056] Step 2: Immerse the indium tin oxide transparent conductive glass completely in deionized water, ultrasonically clean it for 30 minutes, and blow dry it with nitrogen;

[0057] Step 3: Place the indium tin oxide transparent conductive glass in an oxygen plasma cleaning machine for 30 seconds;

[0058] Step 4: Place the indium tin oxide transparent conductive glass in a spin coater, drop 10 μL of PEDOT:PSS on it, and spin coat at 3000 rpm for 30 seconds;

[0059] Step 5: Heat the spin-coated sample to 100 degrees Celsius for 10 minutes and then anneal it.

[0060] Step 6: Mix two organic materials, PCBM and Poly-TPD, with masses of 30.1 mg and 91.1 mg respectively, and 23.6 mg of indium antimonide quantum dots in 5 mL of chlorobenzene solution. At this time, the molar ratio of the three is 1:1:1;

[0061] Step 7: Place the sample from step 5 in a spin coater, take 20 μl of the mixed solution from step 6, and spin coat at 500 rpm for 30 seconds;

[0062] Step 8: Deposit a layer of Y6 as an electron transport layer by magnetron sputtering;

[0063] Step 9: Silver was evaporated for 30 minutes at a pressure of 2.5*10^(-4)Pa and a current of 100A.

[0064] Example 2

[0065] This embodiment is a method for preparing a photodetector using an organic material-indium antimonide quantum dot blend as a photoactive layer, the preparation method comprising the following steps:

[0066] Step 1: Use nitrogen to purge and remove dust from the indium tin oxide transparent conductive glass until there is no obvious impurity dust;

[0067] Step 2: Immerse the indium tin oxide transparent conductive glass completely in deionized water, ultrasonically clean it for 30 minutes, and blow dry it with nitrogen;

[0068] Step 3: Place the indium tin oxide transparent conductive glass in an oxygen plasma cleaning machine for 30 seconds;

[0069] Step 4: Place the indium tin oxide transparent conductive glass in a spin coater, drop 10 μL of PEDOT:PSS on it, and spin coat at 3000 rpm for 30 seconds;

[0070] Step 5: Heat the spin-coated sample to 100 degrees Celsius for 10 minutes and then anneal it.

[0071] Step 6: Mix the organic material TFB and indium antimonide quantum dots in 5 mL of chlorobenzene solution. The mass of the organic material TFB and indium antimonide quantum dots is 70.2 mg and 23.6 mg, respectively, with a molar ratio of 2:1.

[0072] Step 7: Place the sample from step 5 in a spin coater, take 20 μl of the mixed solution from step 6, and spin coat at 500 rpm for 30 seconds;

[0073] Step 8: Deposit a layer of Y6 as an electron transport layer by magnetron sputtering;

[0074] Step 9: Silver was evaporated for 30 minutes at a pressure of 2.5*10^(-4)Pa and a current of 100A.

[0075] Select Example 1, in the wavelength band around 4 microns, the optical power is 0.5mW / cm^-2. Figure 3 As shown in the figure, the current-voltage curve of the photodetector with organic material-InSb quantum dots blended as the photoactive layer is loaded with bias voltage. It can be seen that the prototype exhibits photoelectric response under light excitation. Figure 6 As shown in the figure, the comparison between the prototype and the blank device without photosensitive material shows that the photosensitive layer can generate photocurrent. Figure 4 As shown in the time-current curve of the prototype device under the excitation light cycle switching excitation condition, it can be seen that the prototype device has obvious photoelectric switching function. Figure 5 As shown, the prototype device exhibits an on-response speed of 236ms and an off-response speed of 287ms.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A photoelectric detector, characterized in that: The device structure of the photodetector is, from top to bottom, a metal electrode layer, an electron transport layer, a photosensitive active layer, a hole transport layer, and a transparent conductive glass layer; the photosensitive active layer material is a thin film made by blending organic material and indium antimonide (InSb) quantum dots.

2. A photodetector according to claim 1, characterized in that: The thickness of the metal electrode layer is 50 to 100 nm, the thickness of the electron transport layer is 1 to 30 nm, the thickness of the photoactive layer is 100 to 200 nm, the thickness of the hole transport layer is 1 to 30 nm, the substrate thickness of the transparent conductive glass layer is not limited, and the thickness of the indium tin oxide film of the transparent conductive glass layer is 30 to 380 nm.

3. A photoelectric detector according to claim 1, characterized in that: The organic material is TFB (1,2,4,5-tetrakis(trifluoromethyl)benzene, C 10 H2F 12 ), C 60 (fullerene C60), C 70 (fullerene C70), PCBM (fullerene derivative, C 72 H 14 O2)、Y6(C 82 H 86 F4N8O2S5), Poly-TPD (poly [bis (4-phenyl) (4-butylphenyl) amine], (C 22 H 23 N) x ) or more than one combination thereof.

4. A photoelectric detector according to claim 3, characterized in that: When any two combinations of the organic materials and the indium antimonide quantum dots are mixed, the molar ratio of the three is 0.5-1.5:0.5-1.5:

1.

5. A photodetector according to claim 4, characterized in that: The organic materials are PCBM and Poly-TPD, and the molar ratio of the two organic materials and indium antimonide quantum dots is 1:1:

1.

6. A photoelectric detector according to claim 3, characterized in that: When the organic material is mixed with the indium antimonide quantum dots at any rate, the molar ratio of the two is 1 to 3:

1.

7. A photodetector according to claim 6, characterized in that: The organic material is TFB and indium antimonide quantum dots, and the molar ratio of the two is 2:

1.

8. The photodetector according to claim 1, wherein: The conductive material of the transparent conductive glass layer is indium tin oxide (ITO); the material of the metal electrode layer is Ag, Au or Al thin film; the material of the electron transport layer is C 60 、C 70 Or Y6; the hole transport layer is made of PEDOT:PSS or NiO.

9. The photodetector according to claim 1, wherein: The blending is to mix the organic material and indium antimonide (InSb) quantum dots in a chlorobenzene, toluene or n-hexane solution.

10. A method for preparing a photodetector according to any one of claims 1 to 9, characterized in that: The preparation steps are: 1) Dust removal and cleaning of indium tin oxide transparent conductive glass; 2) preparing a hole transport layer on the clean conductive glass obtained in step 1) by solution spin coating; 3) mixing an organic material and indium antimonide (InSb) quantum dots, and applying the mixed solution to the hole transport layer on the structure obtained in step 2) by drop coating, spin coating, or spray coating to form a thin film as a photoactive layer; 4) preparing an electron transport layer on the photoactive layer obtained in step 3) by a physical deposition process; 5) Vapor-depositing a metal electrode layer on the multilayer structure prepared in step 4).

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