Preparation method of antimony fluoride doped passivated lead sulfide quantum dot active layer

Abstract

The application discloses a preparation method of a fluorinated antimony-doped passivated lead sulfide quantum dot active layer, and the preparation method comprises the following steps: preparing an iodine-bromine-wrapped lead sulfide colloidal quantum dot film; dissolving fluorinated antimony in acetonitrile to obtain a fluorinated antimony acetonitrile solution; soaking the iodine-bromine-wrapped lead sulfide colloidal quantum dot film in the fluorinated antimony acetonitrile solution; and washing the iodine-bromine-wrapped lead sulfide colloidal quantum dot film with acetonitrile for a preset number of times to obtain a fluorinated antimony chemical reaction-doped passivated lead sulfide quantum dot active layer. The application can improve the overall performance of a semiconductor device containing an active layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a preparation method of fluorine-doped antimony-doped passivated lead sulfide quantum dot active layer. BACKGROUND

[0002] Short-wave infrared detector has high resolution, rich target details, and is not affected by thermal cross. At the same time, it can penetrate fog, haze, and dust, and has a long effective detection distance. The most mature technology on the market is indium gallium arsenide (InGaAs) short-wave infrared detector, but the manufacturing process of indium gallium arsenide detector is complex, and InGaAs material cannot be directly epitaxially grown on a silicon substrate, and a complex heterojunction bonding technology is required. Lead sulfide colloidal quantum dots have a large Bohr exciton radius, a narrow band gap, a high extinction coefficient, and a high dielectric constant, and excitons are easy to separate, and the charge collection efficiency is high. They can be easily integrated with silicon-based readout circuits to realize face array imaging, and have great potential in the field of short-wave infrared detection. However, the absorption cutoff band of most lead sulfide quantum dot infrared detectors is within 1650 nm. As the size increases, the surface shape of lead sulfide quantum dots changes from octahedron to truncated octahedron and then to cubic octahedron, the proportion of non-polar faces increases, and the difficulty of ligand exchange increases, leading to incomplete ligand passivation of PbS CQDs active layer, and many defects are introduced into the active layer. At the same time, the wavelength expansion also leads to a larger P-type doping concentration of the quantum dot active layer in the air, and the energy level of the commonly used hole transport layer and electron transport layer in small quantum dot devices will cause energy level mismatch, resulting in a potential barrier, so that the photo-generated carriers cannot be extracted. Therefore, after the wavelength expansion, the overall infrared detector has a large dark current, a small open circuit voltage, and the signal cannot be detected in weak light, and the charge extraction is difficult in strong light, resulting in poor overall performance of semiconductor devices containing active layers. SUMMARY

[0003] The present application aims to at least solve one of the above technical problems by providing a preparation method of fluorine-doped antimony-doped passivated lead sulfide quantum dot active layer, which can improve the overall performance of semiconductor devices containing active layers.

[0004] In one aspect, the present application provides a preparation method of fluorine-doped antimony-doped passivated lead sulfide quantum dot active layer, which comprises:

[0005] Preparation of iodine-bromine-coated lead sulfide colloidal quantum dot film;

[0006] Dissolve fluorine-doped antimony in acetonitrile to obtain a fluorine-doped antimony acetonitrile solution;

[0007] Soak the iodine-bromine-coated lead sulfide colloidal quantum dot film in the fluorine-doped antimony acetonitrile solution;

[0008] The iodine-bromine coated lead sulfide colloidal quantum dot film is washed with acetonitrile for a preset number of times to obtain a lead sulfide quantum dot active layer doped and passivated by antimony fluoride chemical reaction.

[0009] Optionally, the method for preparing the iodine-bromine coated lead sulfide colloidal quantum dot film comprises:

[0010] The lead sulfide colloidal quantum dots are dissolved in a n-octane solvent to obtain a quantum dot n-octane solution, wherein the ligand on the surface of the lead sulfide colloidal quantum dots is oleic acid.

[0011] Lead iodide and lead bromide are dissolved in an N,N-dimethylformamide solution to obtain a first mixed solution, and the quantum dot n-octane solution and the first mixed solution are mixed in equal volumes to obtain a second mixed solution.

[0012] The second mixed solution is oscillated and left to stand until the second mixed solution is stratified into two layers of solutions, the upper layer of the second mixed solution is removed, and a preset volume of n-octane solvent is added to obtain a third mixed solution.

[0013] The third mixed solution is oscillated and left to stand until the third mixed solution is stratified into two layers of solutions, and the upper layer of the third mixed solution is removed to obtain a lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands.

[0014] The lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is subjected to first centrifugal treatment in a centrifuge, and the upper liquid is poured off to remove the residual ligand solution on the surface, and then vacuum drying treatment is performed to obtain iodine-bromine ligand lead sulfide quantum dot powder.

[0015] The iodine-bromine ligand lead sulfide quantum dot powder is dissolved in a dispersant mixed solvent to obtain a fifth mixed solution.

[0016] The fifth mixed solution is oscillated and dispersed and subjected to second centrifugal treatment in a centrifuge.

[0017] The solution after the second centrifugal treatment is spin-coated on a substrate and annealed at a preset annealing temperature for a preset annealing time to obtain an iodine-bromine coated lead sulfide colloidal quantum dot film.

[0018] Optionally, the concentration of the antimony fluoride in the antimony fluoride acetonitrile solution is 1 mmol / L to 10 mmol / L.

[0019] Optionally, the preset number of times is 2.

[0020] Optionally, the concentration of the lead sulfide colloidal quantum dots in the quantum dot n-octane solution is 10 mg / mL.

[0021] Optionally, the dissolving the lead iodide and the lead bromide in the ligand solution to obtain a first mixed solution comprises:

[0022] 1.844 g of lead iodide and 0.32 g of lead bromide are dissolved in 15 mL of DMF solution to obtain a first mixed solution.

[0023] Optionally, the placing the lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands in a centrifuge for first centrifugal treatment and discarding the upper liquid comprises:

[0024] The lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is placed in a centrifuge, the rotation speed of the centrifuge is adjusted to 9000 rpm, and the centrifugal time of the centrifuge is adjusted to 5 min for first centrifugal treatment, and the upper liquid is discarded.

[0025] Optionally, the dispersant mixed solvent is mixed by DMF solvent, DMSO solvent, BTA solvent and pyridine solvent.

[0026] Optionally, the oscillating and dispersing the fifth mixed solution and placing the fifth mixed solution in a centrifuge for second centrifugal treatment comprises:

[0027] The fifth mixed solution is oscillated and placed in a centrifuge for centrifugal treatment at a rotation speed of 2000 rpm for 40 seconds.

[0028] Optionally, the preset annealing temperature is 90 degrees Celsius, and the preset annealing time is 10 minutes.

[0029] The preparation method of the antimony fluoride doped passivated lead sulfide quantum dot active layer provided in the present application comprises the following steps: preparing iodine-bromine coated lead sulfide colloidal quantum dot film; dissolving antimony fluoride in acetonitrile to obtain an antimony fluoride acetonitrile solution; soaking the iodine-bromine coated lead sulfide colloidal quantum dot film in the antimony fluoride acetonitrile solution; and washing the iodine-bromine coated lead sulfide colloidal quantum dot film with acetonitrile for a preset number of times to obtain an antimony fluoride chemically reacted doped passivated lead sulfide quantum dot active layer. The present application can improve the overall performance of the semiconductor device containing the active layer. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a flowchart of an embodiment of the preparation method of the antimony fluoride doped passivated lead sulfide quantum dot active layer provided in the present application;

[0031] Figure 2 is a schematic diagram of the ultraviolet absorption spectrum test of the synthesized oleic acid coated lead sulfide colloidal quantum dot powder;

[0032] Figure 3is a chemical reaction schematic diagram of fluorinated antimony (SbF3) and iodine bromine coated lead sulfide (PbS) quantum dots;

[0033] Figure 4 is a process schematic diagram of preparing dry iodine bromine ligand PbS CQD powder;

[0034] Figure 5 is a schematic diagram of obtaining iodine bromine coated lead sulfide colloidal quantum dot film by spin coating method;

[0035] Figure 6 is a schematic diagram of fluorinated antimony treated lead sulfide quantum dot layer obtained by fluorinated antimony treatment;

[0036] Figure 7 is a schematic diagram of the structure of the active layer quantum dot detector of the trans device structure provided by the embodiments of the present application;

[0037] Figure 8 is a comparison diagram of J-V curves of the active layer quantum dot detector prepared by using fluorinated antimony doped active layer and the active layer not doped with fluorinated antimony;

[0038] Figure 9 is a comparison diagram of J-V curves of 30 doped and undoped SbF3 trans devices; dark a comparison diagram of statistical analysis;

[0039] Figure 10 is a comparison diagram of wide spectrum external quantum efficiency test of the trans device at 0V;

[0040] Figure 11 is the transient photocurrent (TPC) measurement of the SbF3 doped trans device. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0042] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified.

[0043] In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation described as "exemplary" in the present application is not necessarily to be construed as preferred or advantageous over other implementations. The following description is presented to enable any person skilled in the art to make and use the present application. In the following description, details are set forth to provide a thorough understanding of the present application. It will be apparent to one skilled in the art, however, that the present application can be practiced without using these specific details. In other instances, well-known structures and processes have not been described in detail in order to avoid obscuring the description of the present application. Thus, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0044] The present application provides a preparation method of antimony fluoride doped passivated lead sulfide quantum dot active layer, which comprises: preparing an iodine-bromine coated lead sulfide colloidal quantum dot film; dissolving antimony fluoride in acetonitrile to obtain an antimony fluoride acetonitrile solution; soaking the iodine-bromine coated lead sulfide colloidal quantum dot film in the antimony fluoride acetonitrile solution; and washing the iodine-bromine coated lead sulfide colloidal quantum dot film with acetonitrile for a preset number of times to obtain an antimony fluoride chemically reacted doped passivated lead sulfide quantum dot active layer.

[0045] Referring to Figure 1 In the embodiments of the present application, the preparation method of the antimony fluoride doped passivated lead sulfide quantum dot active layer comprises:

[0046] 201. Preparing an iodine-bromine coated lead sulfide colloidal quantum dot film.

[0047] In the embodiments of the present application, the preparation of the iodine-bromine coated lead sulfide colloidal quantum dot film comprises:

[0048] (1) Dissolve the lead sulfide colloidal quantum dots in n-octane solvent to obtain a quantum dot n-octane solution.

[0049] The ligand on the surface of the lead sulfide colloidal quantum dots is oleic acid. The concentration of the lead sulfide colloidal quantum dots in the quantum dot n-octane solution is 10 mg / mL.

[0050] First, the synthesized oleic acid-coated lead sulfide colloidal quantum dot (PbS CQD) powder is weighed, and a quantum dot n-octane solution (PbS CQD / n-octane solution) with a concentration of 10 mg / mL is prepared. The solution is filtered using a syringe and an organic filter head with a pore size of 0.22 μm, and 15 mL is taken in a glass bottle for standby. The synthesized oleic acid-coated lead sulfide colloidal quantum dot (PbS CQD) powder is tested by ultraviolet absorption spectrum as shown in Figure 2 .

[0051] (2) Dissolve lead iodide and lead bromide in N,N-dimethylformamide solution to obtain a first mixed solution, and mix the quantum dot n-octane solution and the first mixed solution in equal volumes to obtain a second mixed solution.

[0052] In the embodiments of the present application, the lead iodide and lead bromide are dissolved in the DMF solution to obtain the first mixed solution, including: 1.844 g of lead iodide and 0.32 g of lead bromide are dissolved in 15 ml of DMF (N,N-dimethylformamide) solution, and the ligand is filtered by a syringe to obtain the first mixed solution. Then, 10 mg / mL of PbS CQD / n-octane solution is slowly injected into the glass bottle containing the ligand solution after being filtered by a syringe in equal volume, so that the short-chain iodine bromide ligand fully exchanges the oleic acid ligand to obtain the second mixed solution.

[0053] (3) Oscillate the second mixed solution and stand until the second mixed solution is layered into two layers of upper and lower solutions, remove the upper layer of the second mixed solution, and add a preset volume of n-octane solvent to obtain a third mixed solution.

[0054] (4) Oscillate the third mixed solution and stand until the third mixed solution is layered into two layers of upper and lower solutions, remove the upper layer of the third mixed solution to obtain a lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands.

[0055] After oscillating the second mixed solution, the glass bottle is left to stand, and after layering, the supernatant is dropped into a waste liquid bottle with a dropper, and an equal amount of n-octane solvent as in the bottle is added to obtain a third mixed solution. After oscillating for 20 seconds, the solution is layered again, and the process is repeated twice to remove excess oleic acid molecules. Then, the lower layer of black lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is equally divided into centrifuge tubes.

[0056] (5) The lead sulfide quantum dot ligand solution with iodine ions and bromide ions as ligands is placed in a centrifuge for first centrifugal treatment and the upper liquid is poured off to remove the residual ligand solution on the surface, and then vacuum drying treatment is performed to obtain iodine bromide ligand lead sulfide quantum dot powder.

[0057] In the embodiment of the present application, the lead sulfide quantum dot ligand solution with iodine ions and bromide ions as ligands is placed in a centrifuge, the speed of the centrifuge is adjusted to 9000 rpm, the centrifugal time of the centrifuge is adjusted to 5 min, first centrifugal treatment is performed, the upper liquid is poured off to remove the residual ligand solution on the surface, and drying treatment is performed to obtain iodine bromide ligand lead sulfide quantum dot powder, which is black precipitate at the bottom, Br-, I-ligand passivated PbS CQD. Then, after removing the residual solvent by vacuum drying, dry iodine bromide ligand PbS CQD powder is obtained.

[0058] (6) The iodine bromide ligand lead sulfide quantum dot powder is dissolved in a dispersant mixed solvent to obtain a fifth mixed solution.

[0059] In the embodiment of the present application, the dispersant mixed solvent is mixed by DMF solvent, DMSO solvent, BTA solvent and pyridine solvent.

[0060] After the dried iodine bromide ligand lead sulfide quantum dot powder is weighed, it is dissolved in a dispersant mixed solvent (DMF:DMSO:BTA:pyridine). DMSO and DMF have high boiling points and polarity, which maintain the electrostatic stability of the slurry. BTA is a short-chain ligand that replaces the remaining oleic acid on the surface of the quantum dots and dissolves the quantum dots. Methylamine pyridine improves the viscosity of the film, and a relatively thick light-absorbing layer is obtained in turn. The PbS CQD slurry concentration is configured to obtain a suitable thickness.

[0061] (7) The fifth mixed solution is oscillation dispersed and placed in a centrifuge for second centrifugal treatment.

[0062] In the embodiment of the present application, the fifth mixed solution is oscillation dispersed and placed in a centrifuge for second centrifugal treatment, which includes: after oscillation of the fifth mixed solution, the fifth mixed solution is placed in a centrifuge for centrifugal treatment at a speed of 2000 rpm for 40 seconds.

[0063] The oscillation of the shaker accelerates the dispersion completely. In order to reduce the large amount of residual solution, the solution is transferred to a 1 mL centrifuge tube using a pipette, and centrifugation is performed again at a speed of 2000 rpm for 40 s.

[0064] (8) The solution after the second centrifugal treatment is spin-coated on a substrate and annealed at a preset annealing temperature for a preset annealing time to obtain an iodine bromide coated lead sulfide colloidal quantum dot film.

[0065] The preset annealing temperature is 90 degrees Celsius, and the preset annealing time is 10 minutes.

[0066] The dimensions are 2.5 × 2.5 cm. 2 The substrate was placed in the center of the suction cup of the spin coater. The vacuum pump was turned on to ensure substrate adsorption, and the spin coating parameters were set. Using a pipette with a volume of 100 μL, 60 μL of the solution after the second centrifugation was taken and dropped onto the substrate. The spin coating button was pressed to perform CQD film deposition. The substrate was then removed and placed on a hot plate at 90°C for about 10 minutes to remove volatile solvents and excess iodine and bromine ligand molecules, resulting in an iodine-bromine-encapsulated lead sulfide colloidal quantum dot film.

[0067] 202. Dissolve antimony fluoride in acetonitrile to obtain an antimony fluoride acetonitrile solution.

[0068] The concentration of antimony fluoride (SbF3) in the antimony fluoride acetonitrile solution is 1 mmol / L to 10 mmol / L.

[0069] 203. Immerse the lead sulfide colloidal quantum dot film coated with iodine bromine in an antimony fluoride acetonitrile solution.

[0070] Antimony (Sb), a Group 15 element, holds promise as an electron donor for lead (Pb), a Group 14 element. Antimony fluoride can replace lead sites in perovskite systems. First, we assessed the theoretical feasibility of introducing antimony fluoride to replace lead in a doping chemical reaction. Table analysis revealed that since both the pre- and post-reaction phases are solid, the entropy change is small, and the Gibbs free energy of the reaction, calculated from bond energies, is less than 0, indicating that the reaction can proceed in the forward direction. Furthermore, due to the surface activity of semiconductor nanocrystals, doping can occur without heating or activation, providing a theoretical chemical basis for introducing antimony fluoride into lead sulfide quantum dot systems to achieve n-type doping.

[0071] like Figure 3 As shown, Figure 3 The chemical reaction of antimony fluoride (SbF3) and lead sulfide (PbS) quantum dots coated with iodine bromine is demonstrated. Figure 3 In the diagram on the left, the larger circle inside the octagon represents sulfur (S), the smaller circle inside the octagon represents lead (Pb), the two circles at the vertices of the outer octagon represent iodine (I), and the circle at the midpoint of the outer edge of the octagon represents bromine (Br). Figure 2In the diagram on the right, the octagon contains three elliptical regions. The larger circle within each elliptical region represents antimony (Sb), and the two smaller circles represent fluorine (F). Outside the elliptical regions, the larger gray circle represents sulfur (S), and the smaller gray circle represents lead (Pb). At the vertices of the octagon's outer edge, the two circles represent iodine (I), and at the midpoints of the outer edges, the two circles represent fluorine (F) and bromine (Br), respectively. As the quantum dot size increases, the crystal planes are not completely covered by ligands, making it easier for Sb to replace Pb on the PbS CQDs crystal planes, and for F to more easily replace S on the lead sulfide surface, thus achieving n-doping.

[0072] 204. The lead sulfide colloidal quantum dot film coated with iodine and bromine was washed with acetonitrile a predetermined number of times to obtain an active layer of lead sulfide quantum dots that was chemically doped and passivated by antimony fluoride.

[0073] The preset number of attempts is 2.

[0074] In this embodiment of the application, the method for preparing the antimony fluoride-doped and passivated lead sulfide quantum dot active layer includes:

[0075] Prepare the following reagents for the experiment: lead iodide (PbI2, 99%, preferred), lead bromide (PbBr2, >98%, preferred), N,N-dimethylformamide (DMF, ultra-dry 99.9%, Aladin), n-octane (95%). The required equipment includes a nitrogen glove box, electronic balance, high-speed centrifuge, hair dryer, etc.

[0076] like Figure 4As shown, the dry iodine bromine ligand PbS CQD powder needs to be obtained by weighing the solution, phase transfer, washing, centrifugation and drying. First, the synthesized oleic acid coated lead sulfide colloidal quantum dot (PbS CQD) powder is weighed to prepare a quantum dot n-octane solution (PbS CQD / n-octane solution) with a concentration of 10 mg / mL. The solution is filtered using a syringe and an organic filter head with a pore size of 0.22 μm, and 15 mL is taken in a glass bottle for standby. A short-chain lead iodide, lead bromide ligand solution is prepared by weighing 1.844 g of lead iodide and 0.32 g of lead bromide, and then filtering the ligand using a syringe to obtain a first mixed solution. Then, the PbS CQD / n-octane solution is slowly injected into the glass bottle containing the ligand solution, so that the short-chain iodine bromine ligand can fully exchange the oleic acid molecules to obtain a second mixed solution. After oscillating the second mixed solution, the glass bottle is left to stand, and after the layers are separated, the supernatant is dropped into a waste bottle with a dropper, and an equal amount of n-octane solvent is added to the bottle to obtain a third mixed solution. After oscillating for 20 seconds, the solution is again separated into layers, and the process is repeated twice to remove excess oleic acid molecules. Then, the lower layer of black lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is equally divided into centrifuge tubes. The lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is placed in a centrifuge, the speed of the centrifuge is adjusted to 9000 rpm, and the centrifugation time of the centrifuge is adjusted to 5 min for the first centrifugation. The upper liquid is poured out to remove the residual ligand solution on the surface, and the iodine bromine ligand lead sulfide quantum dot powder is obtained after drying treatment. The iodine bromine ligand lead sulfide quantum dot powder is the black precipitate of Br-, I-ligand passivated PbS CQD at the bottom. Then, the dry iodine bromine ligand PbS CQD powder is obtained by removing the residual solvent through vacuum drying. The above process is completed in a glove box.

[0077] After the dried iodine bromine ligand lead sulfide quantum dot powder is weighed, it is dissolved in a dispersant mixed solvent (DMF:DMSO:BTA:pyridine). DMSO and DMF have high boiling points and high polarity, which maintain the electrostatic stability of the slurry. BTA is a short-chain ligand that replaces the remaining oleic acid on the surface of the quantum dots and dissolves the quantum dots. Methylamine pyridine improves the viscosity of the film, and the concentration of the PbS CQD slurry is configured in sequence to obtain a relatively thick light-absorbing layer. The solution is transferred to a 1 mL centrifuge tube using a pipette to accelerate complete dispersion. In order to reduce the amount of large residues dissolved, the solution is centrifuged again at a speed of 2000 rpm for 40 s. Figure 5 As shown, the size of the 2.5 x 2.5 cm 2The substrate is placed in the center of the chuck of the spin coater, the vacuum pump is turned on to ensure the substrate is sucked, and the spin coater parameters are set. 60 μΐ of the solution after the second centrifugation is taken out using a micropipette with a range of 100 uL and dropped on the substrate, and the spin coater button is clicked to deposit the CQD film. Then it is taken off and placed on a hot stage at 90°C for annealing for about 10 min to remove the volatile solvent and excess iodine and bromine ligand molecules, and obtain the iodine and bromine coated PbS colloidal quantum dot film.

[0078] As shown in Figure 6 , a certain amount of antimony fluoride is taken and then dissolved in acetonitrile. The PbS CQDs film layer coated with iodine and bromine after ligand exchange is briefly immersed in the antimony fluoride and acetonitrile (ACN) solution, and then washed twice with acetonitrile to remove excess reactants and avoid enrichment of the reactants on the surface of the PbS quantum dots, thereby obtaining the PbS quantum dot layer treated with antimony fluoride. In order to avoid damage to the surface of the PbS film caused by post-treatment chemical doping, we choose the theoretically most gentle antimony fluoride for the experiment. At the same time, in order to avoid damage to the film caused by too high concentration, the concentration is selected to be 1 mmol / L to 10 mmol / L of antimony fluoride acetonitrile solution.

[0079] In order to characterize the advantages of the active layer after chemical doping to the device, we design an active layer quantum dot detector with a reverse structure. The quantum dot from top to bottom of the reverse structure is electrode ITO, hole transport layer NiOx, hole transition layer PbS-EDT, PbS quantum dot layer treated with antimony fluoride PbS-PbI2-SbF3, transition layer C 60 , electron transport layer SnO, top electrode ITO. The active layer quantum dot detector with a reverse structure is shown in Figure 7 .

[0080] Figure 8 The J-V curve comparison diagram of the active layer quantum dot detector without using antimony fluoride doping and the active layer quantum dot detector prepared by doping with antimony fluoride. Among them, the abscissa is the voltage, the ordinate is the current density, control dark represents the dark current density of the active layer without using antimony fluoride doping, control light represents the photocurrent density of the active layer without using antimony fluoride doping, With SbF3 dark represents the dark current density of the active layer using antimony fluoride doping, and With SbF3 light represents the photocurrent density of the active layer using antimony fluoride doping.

[0081] Under the conditions of darkness and 1650 nm LED illumination (270 μW cm -2 ), we record the current density-voltage (J-V) curve of the photodiode, Figure 8 we find that the dark current density (J dark) was significantly lower than that of the undoped trans device. At -10 mV bias, the J dark reached 31 nA cm -2 . The J dark of the control trans device reached 218 nA cm -2 . As the reverse bias increased, the dark current density J dark of the trans device increased sharply. At -0.5 V bias, the J dark of the SbF3-doped trans device remained at 750 nA cm -2 . We carefully examined the photocurrent density-voltage (Jphoto-V) curves and found that the open-circuit voltage of the SbF3-doped trans device was 0.22 V, while that of the control trans device was 0.18 V under 1650 nm illumination at a power density of 270 uW cm -2 . This indicates that the built-in electric field of the SbF3-doped trans device is stronger and can effectively collect photo-generated carriers. This also indicates that the chemical doping of SbF3 reduces the barrier between the PbS quantum dot film and SnO2, allowing photo-generated carriers to be more effectively collected. This enhancement is mainly attributed to the improvement of carrier transport and the reduction of carrier recombination loss.

[0082] To avoid the possibility of chance, we statistically analyzed the J dark of 30 doped or undoped SbF3 trans devices and found that the SbF3-doped trans devices significantly suppressed the dark current at a reverse bias of 0.1 V. The results are shown below Figure 9 . This SbF3 chemical doping post-treatment method can very effectively reduce the device dark current and improve the overall performance of the device. The results are generally applicable.

[0083] Since the light response of our detector reached saturation at zero bias, we performed a wide-spectrum external quantum efficiency test at 0 V, as shown below Figure 10 . Notably, the external quantum efficiency (EQE) of the SbF3-doped trans device reached 56.5% at the peak, which was significantly higher than the 28% external quantum efficiency of the standard trans device. We also calculated the corresponding responsivity (R) of the SbF3 chemical doping trans device at 1.65 μm under 0 V bias, which was 0.738 A W -1 , which was significantly higher than the 0.36 A W -1 of the control trans device under 0 V bias.

[0084] To analyze the kinetics of light-generated carrier transport and recombination in the detector, we performed transient photocurrent (TPC) measurements, as shown below Figure 11The signal change of the two ends of the measured sample is displayed by the oscilloscope. During the TPC measurement, only a 50Ω series resistance is connected, which requires the photo-generated carriers to be transferred to the external circuit for collection. In general, the lifetime obtained from the TPC measurement reflects the carrier transport lifetime in the quantum dot detector, and a shorter lifetime indicates a faster charge transfer and a more efficient charge extraction process. The results show that the charge transfer lifetime of the antimony fluoride doped trans device is 6μs (as shown in FIG. 6), which is higher than that of the general standard trans device. Figure 11

[0085] The preparation method of the antimony fluoride doped and passivated lead sulfide quantum dot active layer in the application comprises the following steps: preparing an iodine-bromine coated lead sulfide colloidal quantum dot film; dissolving antimony fluoride in acetonitrile to obtain an antimony fluoride acetonitrile solution; soaking the iodine-bromine coated lead sulfide colloidal quantum dot film in the antimony fluoride acetonitrile solution; and washing the iodine-bromine coated lead sulfide colloidal quantum dot film with acetonitrile for a preset number of times to obtain an antimony fluoride chemically reacted and doped and passivated lead sulfide quantum dot active layer. The application can improve the overall performance of a semiconductor device containing an active layer.

[0086] The above is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.​

Claims

1. A method for preparing a fluorinated antimony-doped passivated lead sulfide quantum dot active layer, characterized in that, The preparation method of the antimony fluoride doped passivated lead sulfide quantum dot active layer comprises the following steps: iodine and bromine coated lead sulfide colloidal quantum dot film is prepared; antimony fluoride is dissolved in acetonitrile to obtain an antimony fluoride acetonitrile solution; iodine and bromine coated lead sulfide colloidal quantum dot film is soaked in the antimony fluoride acetonitrile solution; iodine and bromine coated lead sulfide colloidal quantum dot film is washed with acetonitrile for a preset number of times to obtain an antimony fluoride chemical reaction doped passivated lead sulfide quantum dot active layer.

2. The method for preparing the antimony fluoride-doped and passivated lead sulfide quantum dot active layer according to claim 1, characterized in that, The preparation method of the iodine and bromine coated lead sulfide colloidal quantum dot film comprises the following steps: lead sulfide colloidal quantum dots are dissolved in n-octane solvent to obtain a quantum dot n-octane solution, wherein the ligand on the surface of the lead sulfide colloidal quantum dots is oleic acid; lead iodide and lead bromide are dissolved in an N,N-dimethylformamide solution to obtain a first mixed solution, and the quantum dot n-octane solution and the first mixed solution are mixed in equal volumes to obtain a second mixed solution; the second mixed solution is oscillated and left to stand until the second mixed solution is separated into two layers of upper and lower solutions, the upper solution of the second mixed solution is removed, and a preset volume of n-octane solvent is added to obtain a third mixed solution; the third mixed solution is oscillated and left to stand until the third mixed solution is separated into two layers of upper and lower solutions, the upper solution of the third mixed solution is removed to obtain a lead sulfide quantum dot ligand solution with iodine and bromine as ligands; the lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is placed in a centrifuge for first centrifugal treatment, the upper liquid is poured out to remove the residual ligand solution on the surface, and vacuum drying treatment is performed to obtain iodine and bromine ligand lead sulfide quantum dot powder; the iodine and bromine ligand lead sulfide quantum dot powder is dissolved in a dispersant mixed solvent to obtain a fifth mixed solution; the fifth mixed solution is oscillated and dispersed and placed in a centrifuge for second centrifugal treatment; the solution after the second centrifugal treatment is spin-coated on a substrate and annealed at a preset annealing temperature for a preset annealing time to obtain iodine and bromine coated lead sulfide colloidal quantum dot film.

3. The method of claim 2, wherein the method further comprises: The concentration of the antimony fluoride in the antimony fluoride acetonitrile solution is 1mmol / L to 10mmol / L.

4. The method of claim 3, wherein the method further comprises: The preset number of times is 2.

5. The method of claim 4, wherein the method further comprises: The concentration of the lead sulfide colloidal quantum dots in the quantum dot n-octane solution is 10mg / mL.

6. The method of claim 5, wherein the method further comprises: The lead iodide and lead bromide are dissolved in the ligand solution to obtain the first mixed solution, which comprises the following steps: 1.844g of lead iodide and 0.32g of lead bromide are dissolved in 15mL of DMF solution to obtain the first mixed solution.

7. The method of claim 6, wherein the method further comprises: The lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is placed in a centrifuge for first centrifugal treatment, and the upper liquid is poured out, which comprises the following steps: The lead sulfide quantum dot ligand solution with iodine ions and bromine ions as ligands is placed in a centrifuge, the rotation speed of the centrifuge is adjusted to 9000rpm, the centrifugal time of the centrifuge is adjusted to 5min, and first centrifugal treatment is performed, and the upper liquid is poured out.

8. The method of claim 7, wherein the method further comprises: The dispersant mixed solvent is mixed by a DMF solvent, a DMSO solvent, a BTA solvent and a pyridine solvent.

9. The method of claim 8, wherein the method further comprises: The fifth mixed solution is oscillated and dispersed and placed in a centrifuge for second centrifugal treatment, which comprises the following steps: After the fifth mixed solution is shaken, it is placed in a centrifuge and centrifuged at a speed of 2000 rpm for 40 seconds.

10. The method for preparing the antimony fluoride-doped and passivated lead sulfide quantum dot active layer according to claim 9, characterized in that, The preset annealing temperature is 90 degrees Celsius, and the preset annealing duration is 10 minutes.

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