ZnTe hole transport layer-based PbS quantum dot detector and preparation method thereof

Abstract

A PbS quantum dot detector based on a ZnTe hole transport layer sequentially comprises a substrate, a bottom electrode, the hole transport layer, a photosensitive layer, an interface layer, an electron transport layer and a top electrode from bottom to top, the hole transport layer is ZnTe, oxidation post-treatment is performed during preparation, the photosensitive layer is PbS-halde, and the preparation method of the detector comprises the following steps: (1) substrate pretreatment; (2) preparing a ZnTe hole transport layer on the substrate with the bottom electrode; (3) preparing a PbS-half photosensitive layer on the ZnTe hole transport layer; (4) preparing an interface layer on the PbS-halite photosensitive layer; (5) preparing an electron transport layer on the interface layer; and (6) preparing a top electrode on the electron transport layer. The ZnTe serves as a hole transport layer material, the technical barrier that the detection performance and the working stability of an existing detector are difficult to balance is broken through, and the comprehensive performance of the quantum dot detector is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to a PbS quantum dot detector based on a ZnTe hole transport layer and a preparation method thereof. Background Art

[0002] Short-wave infrared imaging technology has the advantages of clear details of visible light imaging and strong penetration of medium- and long-wave infrared imaging, and has important application value in the field of infrared detection. Traditional short-wave infrared detectors mainly rely on epitaxial single crystal materials such as indium gallium arsenide and germanium. They have excellent detection performance, but are extremely expensive and cannot be popularized on a large scale. Therefore, the development of low-cost, high-performance short-wave infrared detection technology is not only a hot topic in academic research in the current field, but also a frontier of industrial application.

[0003] PbS quantum dots have the advantages of customizable response bands, integrated with silicon-based readout circuits, and low manufacturing costs, providing new opportunities for the development of a new generation of low-cost, high-performance infrared light detectors. After more than a decade of development, although PbS quantum dot detection technology has made significant progress, its detection performance is still far behind that of traditional detectors, with problems such as high dark current and poor stability, especially in the longer short-wave infrared range.

[0004] The PbS quantum dot detector consists of a transparent conductive electrode, an electron transport layer, a PbS quantum dot photosensitive layer, a hole transport layer, and a bottom electrode. At present, the most widely used hole transport layer is PbS-EDT. Although the thiol-passivated quantum dots have excellent performance, their complex solid-phase ligand exchange steps lead to high material consumption, low film quality, and poor stability, which hinders large-scale development. The use of high-performance and high-stability inorganic materials as hole transport layers to improve the comprehensive performance of PbS quantum dot detectors and promote the widespread application of PbS quantum dot short-wave infrared detection technology has not been reported. Summary of the invention

[0005] The purpose of the present invention is to introduce an inorganic hole transport layer ZnTe into the PbS quantum dot detector to solve the problems of poor film quality and poor stability of the traditional hole transport layer and effectively improve the comprehensive performance of the detector.

[0006] The technical solution of the present invention: A PbS quantum dot detector based on a ZnTe hole transport layer comprises, from bottom to top, a substrate, a bottom electrode, a hole transport layer, a photosensitive layer, an interface layer, an electron transport layer, and a top electrode. The hole transport layer is ZnTe, and the ZnTe hole transport layer is post-oxidized during preparation. The photosensitive layer is a PbS-halide photosensitive layer.

[0007] Preferably, the substrate is a glass substrate; The bottom electrode is an indium tin oxide (ITO) transparent bottom electrode, purchased commercially, with Liaoning being the preferred purchaser, having a thickness of 180 nm and a square resistance of 8 to 10 Ω; The thickness of the ZnTe hole transport layer is 10-160 nm; The thickness of the PbS-halide (PbS quantum dots wrapped with halogen ligands) photosensitive layer is 200-500 nm; The interface layer is C 60 Layer, C 60 The layer thickness is 15~40 nm; The electron transport layer is a SnO2 layer, and the thickness of the SnO2 layer is 20-60 nm; The top electrode is an ITO transparent top electrode, and the thickness of the ITO transparent top electrode is 50-300 nm.

[0008] Further preferably, the ZnTe hole transport layer has a thickness of 80 nm; The thickness of the PbS-halide (PbS quantum dots wrapped with halogen ligands) photosensitive layer is 320 nm; The C 60 The layer thickness is 20 nm; The SnO2 layer has a thickness of 40 nm; The thickness of the ITO transparent top electrode is 180 nm.

[0009] A method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer comprises the following steps: 1. Substrate pretreatment; (ii) preparing a ZnTe hole transport layer on a substrate with a bottom electrode; (iii) preparing a PbS-halide photosensitive layer on the ZnTe hole transport layer; (iv) preparing an interface layer on the PbS-halide photosensitive layer; (5) preparing an electron transport layer on the interface layer; (vi) Preparing a top electrode on the electron transport layer.

[0010] Preferably, the substrate pretreatment in step (i) is glass substrate pretreatment, specifically: the glass substrate with the ITO transparent bottom electrode is washed with deionized water and ethanol in sequence, and then blown dry with an air gun.

[0011] Preferably, the preparation method of the ZnTe hole transport layer in step (ii) is magnetron sputtering, the vacuum degree of sputtering is 0.5-4 Pa, and the heating temperature during the post-oxidation treatment of the ZnTe hole transport layer is 100-300°C for 30-300 min.

[0012] Further preferably, the vacuum degree of sputtering in the step (ii) is 1 Pa.

[0013] Preferably, the preparation method of the PbS-halide photosensitive layer in step (iii) is a spin coating method, specifically: (1) preparing a halogen-containing N,N-dimethylformamide (DMF) ligand solution, wherein the ligand solution is composed of one or two of lead iodide, lead bromide, ammonium chloride and ammonium iodide; (2) mixing an octane solution (10 mg / mL) of PbS-OA quantum dots having a first exciton absorption peak of 980-1700 nm with the ligand solution to perform ligand exchange; (3) after the exchange, vacuum drying the quantum dots; (4) dispersing the PbS-halide quantum dots with a mixed solution of mono-n-butylamine (BTA) and DMF at a concentration of 200-500 mg / mL, spin coating the substrate at a speed of 2500 rpm for 40 s, and then annealing it at 90°C for 10 min to obtain the PbS-halide photosensitive layer.

[0014] Further preferably, in the step (iii), the PbS-halide quantum dots are dispersed with a mixed solution of BTA and ligands at a concentration of 350 mg / mL.

[0015] Preferably, in step (iv), the interface layer is C 60 Layer, C 60 The layer was prepared by thermal evaporation with an evaporation rate of 0.07~0.12 Å / s.

[0016] Further preferably, the evaporation rate in step (iv) is 0.1 Å / s.

[0017] Preferably, in the step (v), the electron transport layer is a SnO2 layer, the SnO2 layer is prepared by atomic layer deposition, and the heating temperature of the tin source is 50-90°C.

[0018] Further preferably, in the step (v), the heating temperature of the tin source is 60°C.

[0019] Preferably, in step (six), the top electrode is an ITO transparent top electrode, and the preparation method of the ITO transparent top electrode is a magnetron sputtering method, the vacuum degree of sputtering is 0.2~1 Pa, and the O2 / Ar flow ratio of sputtering is 0.017~0.

[0020] Further preferably, in the step (six), the vacuum degree of sputtering is 0.5 Pa, and the O2 / Ar flow ratio of sputtering is 0.003.

[0021] Beneficial effects of the present invention: Compared with the prior art, the present invention proposes for the first time that ZnTe material be used as the hole transport layer of the PbS quantum dot short-wave infrared detector. ZnTe as a hole transport layer material has the following advantages at least: First, ZnTe material can be prepared by magnetron sputtering vacuum coating technology, and the process repeatability is high; Second, the vacuum preparation process can improve the uniformity and density of the transport layer, thereby improving the uniformity of the distribution of the device's light response and dark current, which is conducive to reducing the difference between different pixels of the chip and improving the imaging quality of the chip; Third, as a common inorganic semiconductor material, ZnTe has excellent chemical stability and is an ideal hole transport layer choice for high-stability detectors; Fourth, the energy level matching degree between ZnTe and the PbS quantum dot photosensitive layer is high, which is conducive to the transport of photogenerated carriers. To this end, the present invention proposes a ZnTe hole transport layer, breaking through the technical barriers of the existing detectors that are difficult to balance between detection performance and working stability, and improving the comprehensive performance of quantum dot detectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the PbS quantum dot detector of the present invention; Among them: 1. substrate, 2. bottom electrode, 3. hole transport layer, 4. photosensitive layer, 5. interface layer, 6. electron transport layer, 7. top electrode.

[0023] Figure 2 The scanning electron microscope images of the ZnTe film in Example 1 and the PbS-EDT film in Comparative Example 1 are shown; Figure 3 Conductive atomic force microscope electron microscope images of the ZnTe film in Example 1 and the PbS-EDT film in Comparative Example 1; Figure 4 Aging time-current curves of ZnTe and PbS-EDT photoconductive devices; Figure 5 Absorption spectra of ZnTe and PbS-EDT films before and after aging; Figure 6 The current-voltage characteristic curves of the PbS quantum dot detector based on the ZnTe hole transport layer in Example 1 and the PbS quantum dot detector based on the PbS-EDT hole transport layer in Comparative Example 1; Figure 7 The current-voltage characteristic curves of the PbS quantum dot detector based on the oxidation post-treatment of the ZnTe hole transport layer in Example 1 and the non-oxidation post-treatment of the ZnTe hole transport layer in Comparative Example 2; Figure 8 The current-voltage characteristic curves of the PbS quantum dot detector based on the air heat treatment of the ZnTe hole transport layer in Example 1 and the nitrogen heat treatment of the ZnTe hole transport layer in Comparative Example 3. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the present invention is not limited to the following examples. The methods are conventional methods unless otherwise specified. The raw materials can be obtained from public commercial channels unless otherwise specified.

[0025] The PbS quantum dot detector based on the ZnTe hole transport layer of the present invention comprises, from bottom to top, a substrate 1, a bottom electrode 2, a hole transport layer 3, a photosensitive layer 4, an interface layer 5, an electron transport layer 6, and a top electrode 7, wherein the substrate 1 is a glass substrate, the bottom electrode 2 is an ITO transparent bottom electrode, the hole transport layer 3 is a ZnTe hole transport layer, the ZnTe hole transport layer is subjected to post-oxidation treatment during preparation, the photosensitive layer 4 is a PbS-halide photosensitive layer, and the interface layer 5 is a C 60 layer, the electron transport layer 6 is a SnO2 layer, and the top electrode 7 is an ITO transparent top electrode.

[0026] Example 1 1) Pre-treat the glass substrate as follows: wash the glass substrate with the ITO transparent bottom electrode with deionized water and ethanol, and then blow dry with an air gun; 2) On a glass substrate with an ITO transparent bottom electrode, a hole transport layer is prepared. The hole transport layer ZnTe in this embodiment is prepared by magnetron sputtering. The specific process parameters are as follows: the sputtering vacuum is 1 Pa, the sputtering power is 100 W, and a 80 nm thick ZnTe layer is prepared; then, the ZnTe layer is subjected to oxidation post-treatment in air at a heating temperature of 100°C for 60 min; 3) On the hole transport layer, a PbS-halide layer was prepared by spin coating. The specific steps are as follows: first, a DMF solution of lead iodide (0.266 M) and lead bromide (0.052 M) was prepared as a ligand solution. Then, an n-octane solution (10 mg / mL) of PbS-OA quantum dots with a first exciton absorption peak of 1300 nm was mixed with the ligand solution in a volume ratio of 1:1. The mixed solution was shaken until the quantum dots were completely transferred to the DMF phase. Then, the n-octane solution on the upper layer was removed and the DMF solution was washed twice with n-octane. After the exchange process, the quantum dots were separated from the solvent by centrifugation. The quantum dots were then vacuum dried and the PbS-halide quantum dots were dispersed with a mixed solution of BTA: DMF (volume ratio 4:1) at a concentration of 350 mg / mL. The PbS-halide quantum dots were spin coated on the substrate at a speed of 2500 rpm for 40 s. Then, the substrate was annealed at 90°C for 10 min to obtain 320 nm thick PbS-halide photosensitive layer; 4) On the PbS-halide photosensitive layer, C was prepared by thermal evaporation 60The specific process parameters are as follows: evaporation rate is 0.1 Å / s, evaporation time is 33 min 20 s, and 20 nm thick C 60 layer; 5) In C 60 On the layer, the SnO2 layer was prepared by atomic layer deposition. The specific process parameters were as follows: the heating temperature of the tin source was 60 °C, the gas flow rate was 100 sccm, the water source gas flow rate was 100 sccm, the deposition time was 1.5 h, and a 40 nm thick SnO2 layer was obtained; 6) On the SnO2 layer, an ITO transparent top electrode was prepared by magnetron sputtering. The specific process parameters were as follows: sputtering vacuum degree was 0.5 Pa, sputtering O2 / Ar flow ratio was 0.003, sputtering power was 100 W, sputtering time was 15 min, and a 180 nm thick ITO transparent top electrode layer was obtained; Finally, the PbS quantum dot detector based on the ZnTe hole transport layer of the present invention is obtained. The detector structure is composed of: glass substrate, ITO bottom electrode, ZnTe layer, PbS-halide layer, C 60 layer, SnO2 layer and ITO top electrode.

[0027] Comparative Example 1 (Compared with Example 1) In this comparative example, except that step 2) the preparation of the hole transport layer is different from the preparation method of the hole transport layer in Example 1, the other steps are the same as Example 1. Specifically, step 2) of this comparative example is: A hole transport layer was prepared on a glass substrate with an ITO transparent bottom electrode. A traditional PbS-EDT hole transport layer was prepared by spin coating. The specific steps were as follows: 50 μL of a 40 mg / mL PbS-OA quantum dot n-octane solution was taken and spin coated on the substrate at 2500 rpm for 20 seconds, and then a 0.02% EDT acetonitrile solution was dropped on the substrate and reacted for 20 seconds. Subsequently, the substrate was washed twice with acetonitrile, spin coated, and the excess solvent was dried. The above steps were repeated once to prepare a PbS-EDT quantum dot film of the required thickness for the device.

[0028] Comparative Example 2 (Compared with Example 1) 1) Pre-treat the glass substrate as follows: wash the glass substrate with the ITO transparent electrode with deionized water and ethanol, and then blow dry with an air gun; 2) On a glass substrate with ITO, a ZnTe hole transport layer was prepared by magnetron sputtering. The specific process parameters were as follows: the sputtering vacuum was 1 Pa, the sputtering power was 100 W, and an 80 nm thick ZnTe layer was prepared without any post-treatment of the ZnTe layer; 3) On the ZnTe hole transport layer, a PbS-halide layer was prepared by spin coating. The specific steps are as follows: first, a DMF solution of lead iodide (0.266 M) and lead bromide (0.052 M) was prepared as a ligand solution. Then, an n-octane solution (10 mg / mL) of PbS-OA quantum dots with a first exciton absorption peak of 1300 nm was mixed with the ligand solution in a volume ratio of 1:1. The mixed solution was shaken until the quantum dots were completely transferred to the DMF phase. Then, the n-octane solution on the upper layer was removed and the DMF solution was washed twice with n-octane. After the exchange process, the quantum dots were separated from the solvent by centrifugation. The quantum dots were then vacuum dried and the PbS-halide quantum dots were dispersed with a mixed solution of BTA: DMF (volume ratio 4:1) at a concentration of 350 mg / mL. The PbS-halide quantum dots were spin coated on the substrate at a speed of 2500 rpm for 40 s. Then, the mixture was annealed at 90°C for 10 min to obtain 320 nm thick PbS-halide photosensitive layer; 4) On the PbS-halide photosensitive layer, C was prepared by thermal evaporation 60 The specific process parameters are as follows: evaporation rate is 0.1 Å / s, evaporation time is 33 min 20 s, and 20 nm thick C 60 layer; 5) In C 60 On the layer, the SnO2 layer was prepared by atomic layer deposition. The specific process parameters were as follows: the heating temperature of the tin source was 60 °C, the gas flow rate was 100 sccm, the water source gas flow rate was 100 sccm, the deposition time was 1.5 h, and a 40 nm thick SnO2 layer was obtained; 6) On the SnO2 layer, an ITO transparent top electrode was prepared by magnetron sputtering. The specific process parameters were as follows: sputtering vacuum degree was 0.5 Pa, sputtering O2 / Ar flow ratio was 0.003, sputtering power was 100 W, sputtering time was 15 min, and a 180 nm thick ITO transparent top electrode layer was obtained; Finally, the PbS quantum dot detector based on the ZnTe hole transport layer of the present invention is obtained; the detector structure comprises, from bottom to top, a glass substrate, an ITO bottom electrode, a ZnTe layer, a PbS-halide layer, a C 60 layer, SnO2 layer and ITO top electrode.

[0029] Comparative Example 3 (Compared with Example 1) 1) Pre-treat the glass substrate as follows: wash the glass substrate with the ITO transparent electrode with deionized water and ethanol, and then blow dry with an air gun; 2) On a glass substrate with ITO, a ZnTe hole transport layer was prepared by magnetron sputtering. The specific process parameters were as follows: the sputtering vacuum was 1 Pa, the sputtering power was 100 W, and an 80 nm thick ZnTe layer was prepared. Then, the ZnTe layer was heat treated in a nitrogen environment at a heating temperature of 100 °C for 60 min. 3) On the ZnTe hole transport layer, the PbS-halide layer was prepared by spin coating. The specific steps are as follows: First, prepare a DMF solution of lead iodide (0.266 M) and lead bromide (0.052 M) as a ligand solution. Then, mix the n-octane solution (10 mg / mL) of PbS-OA quantum dots with a first exciton absorption peak of 1300 nm with the ligand solution at a volume ratio of 1:1. The mixed solution was shaken until the quantum dots were completely transferred to the DMF phase. Then, the n-octane solution on the upper layer was removed and the DMF solution was washed twice with n-octane. After the exchange process, the quantum dots were separated from the solvent by centrifugation. The quantum dots were then vacuum dried, and the PbS-halide quantum dots were dispersed with a mixed solution of BTA: DMF (volume ratio 4: 1) at a concentration of 350 mg / mL, and spin coated on the substrate at a speed of 2500 rpm for 40 s. Then, it was annealed at 90 °C for 10 min to obtain a 320 nm thick PbS-halide photosensitive layer; 4) On the PbS-halide photosensitive layer, C was prepared by thermal evaporation 60 The specific process parameters are as follows: evaporation rate is 0.1 Å / s, evaporation time is 33 min 20 s, and 20 nm thick C 60 layer; 5) In C 60 On the layer, the SnO2 layer was prepared by atomic layer deposition. The specific process parameters were as follows: the heating temperature of the tin source was 60 °C, the gas flow rate was 100 sccm, the water source gas flow rate was 100 sccm, the deposition time was 1.5 h, and a 40 nm thick SnO2 layer was obtained; 6) On the SnO2 layer, an ITO transparent top electrode was prepared by magnetron sputtering. The specific process parameters were as follows: sputtering vacuum degree was 0.5 Pa, sputtering O2 / Ar flow ratio was 0.003, sputtering power was 100 W, sputtering time was 15 min, and a 180 nm thick ITO transparent top electrode layer was obtained; Finally, the PbS quantum dot detector based on the ZnTe hole transport layer of the present invention is obtained; the detector structure comprises, from bottom to top, a glass substrate, an ITO bottom electrode, a ZnTe layer, a PbS-halide layer, a C 60 layer, SnO2 layer and ITO top electrode.

[0030] Depend on Figure 2 It can be seen that the traditional PbS-EDT film has obvious cracks, while the ZnTe film has good quality.

[0031] Depend on Figure 3 It can be seen that compared with the ZnTe film, the surface current uniformity of the PbS-EDT film is poor.

[0032] Depend on Figure 4 It can be seen that after heat treatment, the conductivity of the PbS-EDT device is more than doubled, however, the conductivity of the ZnTe photoconductive device remains unchanged, indicating that the thermal stability of the ZnTe material is good.

[0033] Depend on Figure 5 It can be seen that after heat treatment, the PbS-EDT exciton absorption peak red-shifts and the peak becomes broader with heating. However, the absorption spectrum of the ZnTe film remains unchanged before and after heating, which once again shows that the ZnTe material has good thermal stability.

[0034] Depend on Figure 6 It can be seen that the PbS quantum dot detector based on the ZnTe hole transport layer has higher photocurrent and lower dark current.

[0035] Depend on Figure 7 It can be seen that the PbS quantum dot detector based on the post-oxidation treatment of the ZnTe hole transport layer has a higher photocurrent and a lower dark current, indicating that the oxidation of the ZnTe hole transport layer is very important for improving the performance of the device.

[0036] Depend on Figure 8 It can be seen that heat treatment in a nitrogen environment has little effect on the performance of PbS quantum dot detectors. Therefore, oxidation is essential for high-performance ZnTe hole transport layer-based detectors.

[0037] The ZnTe material in the present invention can be prepared by magnetron sputtering vacuum coating technology, and the process repeatability is high; the vacuum preparation process can improve the uniformity and density of the transmission layer, thereby improving the light response of the device and the distribution uniformity of the dark current, which is beneficial to reducing the difference between different pixels of the chip and improving the imaging quality of the chip; the ZnTe and PbS quantum dot photosensitive layers have a high energy level matching degree, which is beneficial to the transport of photogenerated carriers and improves the comprehensive performance of the quantum dot detector.

Claims

1. A PbS quantum dot detector based on a ZnTe hole transport layer, comprising, from bottom to top, a substrate, a bottom electrode, a hole transport layer, a photosensitive layer, an interface layer, an electron transport layer, and a top electrode, characterized in that: The hole transport layer is ZnTe, and the ZnTe hole transport layer is post-oxidized during preparation. The photosensitive layer is a PbS-halide photosensitive layer.

2. A PbS quantum dot detector based on a ZnTe hole transport layer as claimed in claim 1, characterized in that: The substrate is a glass substrate; The bottom electrode is an indium tin oxide (ITO) transparent bottom electrode, purchased commercially, with Liaoning being the preferred purchaser, having a thickness of 180 nm and a square resistance of 8 to 10 Ω; The thickness of the ZnTe hole transport layer is 10-160 nm; The thickness of the PbS-halide (PbS quantum dots wrapped by halogen ligands) photosensitive layer is 200-500 nm; the interface layer is C 60 Layer, C 60 The layer thickness is 15~40 nm; The electron transport layer is a SnO2 layer, and the thickness of the SnO2 layer is 20-60 nm; The top electrode is an ITO transparent top electrode, and the thickness of the ITO transparent top electrode is 50-300 nm.

3. A PbS quantum dot detector based on a ZnTe hole transport layer as claimed in claim 1, characterized in that: The thickness of the ZnTe hole transport layer is 80 nm; The thickness of the PbS-halide (PbS quantum dots wrapped with halogen ligands) photosensitive layer is 320 nm; The C 60 The layer thickness is 20 nm; The SnO2 layer has a thickness of 40 nm; The thickness of the ITO transparent top electrode is 180 nm.

4. A method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer as claimed in any one of claims 1 to 3, characterized in that: The steps include:

1. Substrate pretreatment; (ii) preparing a ZnTe hole transport layer on a substrate with a bottom electrode; (iii) preparing a PbS-halide photosensitive layer on the ZnTe hole transport layer; (iv) preparing an interface layer on the PbS-halide photosensitive layer; (5) preparing an electron transport layer on the interface layer; (vi) Preparing a top electrode on the electron transport layer.

5. A method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer as claimed in claim 4, characterized in that: The substrate pretreatment in step (i) is glass substrate pretreatment, specifically: the glass substrate with the ITO transparent bottom electrode is cleaned with deionized water and ethanol in sequence, and then blown dry with an air gun.

6. A method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer as claimed in claim 4, characterized in that: In the step (ii), the ZnTe hole transport layer is prepared by magnetron sputtering, the vacuum degree of sputtering is 0.5-4 Pa, and the heating temperature during the oxidation post-treatment of the ZnTe hole transport layer is 100-300°C for 30-300 min.

7. A method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer as claimed in claim 4, characterized in that: The preparation method of the PbS-halide photosensitive layer in step (iii) is a spin coating method, specifically: (1) preparing a halogen-containing N,N-dimethylformamide (DMF) ligand solution, wherein the ligand solution is composed of one or two of lead iodide, lead bromide, ammonium chloride and ammonium iodide; (2) mixing an octane solution (10 mg / mL) of PbS-OA quantum dots having a first exciton absorption peak of 980-1700 nm with the ligand solution to perform ligand exchange; (3) after the exchange, vacuum drying the quantum dots; (4) dispersing the PbS-halide quantum dots with a mixed solution of mono-n-butylamine (BTA) and DMF to a concentration of 200-500 mg / mL, spin coating the substrate at a speed of 2500 rpm for 40 s, and then annealing it at 90°C for 10 min to obtain the PbS-halide photosensitive layer.

8. The method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer according to claim 4, characterized in that: In the step (iv), the interface layer is C 60 Layer, C 60 The layer was prepared by thermal evaporation with an evaporation rate of 0.07~0.12Å / s.

9. The method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer according to claim 4, characterized in that: In the step (v), the electron transport layer is a SnO2 layer, the SnO2 layer is prepared by atomic layer deposition, and the heating temperature of the tin source is 50-90°C.

10. A method for preparing a PbS quantum dot detector based on a ZnTe hole transport layer as claimed in claim 4, characterized in that: In the step (six), the top electrode is an ITO transparent top electrode, and the preparation method of the ITO transparent top electrode is a magnetron sputtering method, the vacuum degree of sputtering is 0.2~1 Pa, and the O2 / Ar flow ratio of sputtering is 0.017~0.

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