Chiral photoconductive device, preparation method thereof and chiral photoelectric detector

Abstract

The invention relates to the technical field of photoelectricity, and discloses a chiral photoconductive device, a preparation method thereof and a chiral photoelectric detector. The method comprises the following steps: preparing lead sulfide quantum dots; the lead sulfide quantum dots are dissolved in normal octane, a first solution is obtained, and the concentration of the lead sulfide quantum dots in the first solution is 50 mg / ml; a prefabricated chiral ligand is dissolved in methyl alcohol, a second solution is obtained, and the concentration of the chiral ligand in the second solution is 5 mg / ml; cleaning the preset glass sheet plated with the conductive material by using ethanol, and removing residual ethanol after cleaning to obtain a prefabricated substrate; and sequentially spin-coating the first solution and the second solution on the prefabricated substrate according to a preset layer number, and carrying out annealing treatment to obtain a target chiral photoconductive device. The chiral photoconductive device prepared by the method has different absorption on left-handed circularly polarized light and right-handed circularly polarized light, can realize circularly polarized light detection in a short-wave infrared band range, and is high in photoelectric anisotropy and excellent in photoelectric property.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a chiral photoconductive device and a preparation method thereof, and a chiral photodetector. Background Art

[0002] Circularly polarized luminescence (CPL) can be divided into left-handed circularly polarized luminescence (LCPL) and right-handed circularly polarized luminescence (RCPL) according to the rotation direction of the light vector. Both left-handed circularly polarized luminescence and right-handed circularly polarized luminescence can be used as two independent channels to transmit information, thereby doubling the transmission speed compared to unpolarized light. The traditional method of detecting circularly polarized light is to pass the circularly polarized light through a quarter-wave plate to convert the circularly polarized light into linearly polarized light, then pass the linearly polarized light through a polarizer with a known direction, and finally use an ordinary photodetector to detect the light intensity of the emitted light. This method of detecting CPL involves multiple optical components, which hinders the miniaturization and integration of circularly polarized light photodetectors. Chiral materials have a non-centrosymmetric structure different from the mirror image, cannot overlap each other, and show nonlinear optical response to circularly polarized light in the circular dichroism spectrum. However, current devices that can distinguish left-handed and right-handed light combine polarization-insensitive inorganic photodetectors with rigid, bulky optical components, limiting the detectable spectral range of the photodetectors. In addition, efficient short-wave infrared (SWIR) detection of circularly polarized light provides technical support for the next generation of quantum information, model encryption, remote sensing, etc., but traditional short-wave infrared circularly polarized light detectors usually require the installation of external optical devices, making it difficult to achieve integrated and flexible circularly polarized light detection equipment. Summary of the invention

[0003] The main technical problems solved by the implementation methods of the present application are that traditional quantum dot photodetectors have poor light absorption performance in the short-wave infrared region, are polarization insensitive, and have insufficient photoelectric detection performance.

[0004] To solve the above technical problems, the first technical solution adopted in the implementation mode of the present application is: providing a method for preparing a chiral photoconductive device, comprising: preparing lead sulfide quantum dots; dissolving the lead sulfide quantum dots in n-octane to obtain a first solution, wherein the concentration of the lead sulfide quantum dots in the first solution is 50 mg / ml; dissolving a prefabricated chiral ligand in methanol to obtain a second solution, wherein the concentration of the chiral ligand in the second solution is 5 mg / ml; using ethanol to clean a preset glass sheet coated with a conductive material, and removing the remaining ethanol after cleaning to obtain a prefabricated substrate; spin-coating the first solution and the second solution onto the prefabricated substrate in sequence according to a preset number of layers, and performing annealing treatment to obtain a target chiral photoconductive device.

[0005] Optionally, the step of preparing lead sulfide quantum dots includes: preparing a lead source precursor; uniformly mixing 2.7 mL of 1-octadecene and 0.3 mL of hexamethyldisilathione to obtain the prefabricated sulfur source; introducing nitrogen into the lead source precursor, and injecting the prefabricated sulfur source when the reaction temperature drops to 100° C. to obtain a lead sulfide quantum dot stock solution; adding n-hexane and acetone to the lead sulfide quantum dot stock solution, and stirring at a speed of 7000 rpm for 3 minutes to obtain a fourth solution; washing the fourth solution 2 or 3 times, removing the clear liquid after washing, and drying to obtain the lead sulfide quantum dots.

[0006] Optionally, the step of preparing the lead source precursor includes: taking 0.45g of lead oxide and 12ml of 1-octadecene and adding them to 8ml of oleic acid to obtain a third solution; heating the third solution to 40°C under a nitrogen atmosphere, and stirring the third solution at a speed of 500 rpm; transferring the third solution to a continuously vacuumed environment, heating the third solution to 120°C and maintaining it for at least 2 hours to obtain the lead source precursor.

[0007] Optionally, the step of spin coating the first solution and the second solution onto the prefabricated substrate and performing annealing treatment includes: vacuum adsorbing the prefabricated substrate by a coater and setting the rotation speed of the coater to a first rotation speed; spin coating a first volume of the first solution onto the prefabricated substrate on the coater for a first time to obtain a first quantum dot film; taking a second volume of the second solution and dropping it on the first quantum dot film and letting it stand for a second time, and then driving the coater at a second rotation speed for a third time to remove the remaining second solution; driving the coater and using methanol reagent to clean the first quantum dot film on the coater to obtain a single-layer chiral quantum dot film; standing for one minute, and continuing to repeatedly spin coat the first volume of the first solution and the second volume of the second solution onto the newly obtained single-layer chiral quantum dot film until the number of spin coating times is equal to the preset number of layers to obtain a multi-layer chiral quantum dot film; annealing the multi-layer chiral quantum dot film in an environment of 85°C for 10 minutes to obtain the target chiral photoconductive device.

[0008] Optionally, the chiral ligand is a D-chiral ligand or an L-chiral ligand; and the preset number of layers is five or nine.

[0009] Optionally, the first rotation speed of the glue spreading machine is 4000 rpm, and the second rotation speed is 3000 rpm.

[0010] Optionally, the first time for the glue spreader to spin coat is 30 seconds, the second time for the silent process to last is 30 seconds, and the third time for the glue spreader to be driven is 10 seconds.

[0011] Optionally, the first volume of the first solution is 40 μl, and the second volume of the second solution is 500 μl.

[0012] In order to solve the above technical problems, the second technical solution adopted in the embodiment of the present application is: to provide a chiral photoconductive device, wherein the chiral photoconductive device is prepared by the chiral photoconductive device preparation method as described above.

[0013] In order to solve the above technical problems, the third technical solution adopted in the embodiment of the present application is: to provide a chiral photodetector, wherein the chiral photodetector includes the chiral photoconductive device as described above.

[0014] Different from the related art, the present application obtains a chiral inorganic material - lead sulfide quantum dots by simple ligand exchange between lead sulfide quantum dots and chiral ligands, and uses the chiral inorganic material - lead sulfide quantum dots to prepare a corresponding chiral photoconductive device, which has a good light-dark separation effect and a high responsiveness, and has different absorption of left-handed circularly polarized light and right-handed circularly polarized light, and has a high degree of discrimination between circularly polarized lights of different handedness, can realize circularly polarized light detection in the short-wave infrared band, and also has high photoelectric anisotropy, excellent photoelectric performance, high stability, and good repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0016] Figure 1 It is a schematic flow chart of the method for preparing a chiral photoconductive device provided in an embodiment of the present application.

[0017] Figure 2 It is a UV-visible absorption spectrum diagram of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the embodiments of the present application in the range of 200 nanometers to 800 nanometers.

[0018] Figure 3 It is the circular dichroism spectrum of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the examples of the present application in the range of 200 nanometers to 800 nanometers.

[0019] Figure 4 It is a UV-visible absorption spectrum diagram of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the embodiments of the present application in the range of 800 nanometers to 1600 nanometers.

[0020] Figure 5 It is the circular dichroism spectrum of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the examples of the present application in the range of 800 nanometers to 1600 nanometers.

[0021] Figure 6 This is a graph showing the relationship between the photocurrent and dark current of a nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with left-handed circularly polarized light as a function of voltage.

[0022] Figure 7 This is a graph showing the relationship between the photocurrent and dark current of a nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage.

[0023] Figure 8 This is a relationship diagram of the photocurrent and dark current of the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application under left-handed circularly polarized light as a function of voltage.

[0024] Fig. 9 This is a relationship diagram of the photocurrent and dark current of the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage.

[0025] Fig.10 This is a graph showing the responsiveness test results of the nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application.

[0026] Fig.11 This is a graph showing the responsiveness test results of the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application.

[0027] Fig.12 This is a graph showing the relationship between the photocurrent and dark current of a five-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with left-handed circularly polarized light as a function of voltage.

[0028] Fig.13 This is a graph showing the relationship between the photocurrent and dark current of a five-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage.

[0029] Fig.14 This is a relationship diagram of the photocurrent and dark current of the five-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application when irradiated with left-handed circularly polarized light as a function of voltage.

[0030] Fig.15 This is a graph showing the relationship between the photocurrent and dark current of a five-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage.

[0031] Fig.16 This is a graph showing the responsiveness test results of the five-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application.

[0032] Fig.17 This is a graph showing the responsiveness test results of a five-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the following embodiments are provided in order to better further understand the present invention, but are not limited to the best implementation mode described, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the present invention with the features of other prior arts shall fall within the protection scope of the present invention.

[0034] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0035] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0036] The following specific examples are further explanations of the present invention. The examples cited cannot list all the embodiments of the present invention. Only some of the embodiments are used as examples for explanation. The specific examples are as follows:

[0037] Example 1

[0038] Example 1 of the present application provides a method for preparing a chiral photoconductive device. Figure 1 , Figure 1 : is a schematic diagram of a method for preparing a chiral photoconductive device provided in an embodiment of the present application, and the specific steps are as follows:

[0039] S1: Preparation of lead sulfide quantum dots.

[0040] As an optional embodiment, the above step S1 may specifically include: first, prepare a lead source precursor. Then, evenly mix 2.7 mL of 1-octadecene and 0.3 mL of hexamethyldisilathione to obtain the prefabricated sulfur source; introduce nitrogen into the lead source precursor, and inject the prefabricated sulfur source when the reaction temperature drops to 100°C to obtain a lead sulfide quantum dot stock solution; add n-hexane and acetone to the lead sulfide quantum dot stock solution, and stir at 7000 rpm for 3 minutes to obtain a fourth solution. Finally, wash the fourth solution 2 or 3 times, remove the clear liquid after washing, and then dry it (for example, invert for one minute to dry) to obtain the lead sulfide quantum dots, and put the lead sulfide quantum dots into a glove box for solid storage.

[0041] As another optional embodiment, the step of preparing the lead source precursor may specifically include: first, taking 0.45g of lead oxide and 12ml of 1-octadecene and adding them to 8ml of oleic acid to obtain a third solution. Then, heating the third solution to 40°C under a nitrogen atmosphere, and stirring the third solution at a speed of 500 rpm; slowly evacuating, and when a large number of bubbles appear, adjusting the evacuation rate, waiting for 30 seconds, adjusting the nitrogen state, and repeating the operation three times, and finally maintaining the evacuation state, heating the third solution to 120°C and maintaining it for at least 2 hours to obtain the lead source precursor.

[0042] S2: dissolving the lead sulfide quantum dots in n-octane to obtain a first solution, wherein the concentration of the lead sulfide quantum dots in the first solution is 50 mg / ml.

[0043] S3: dissolving the preformed chiral ligand in methanol to obtain a second solution, wherein the concentration of the chiral ligand in the second solution is 5 mg / ml.

[0044] Among them, the chiral ligands that can be used in the present application include but are not limited to: tartaric acid, malic acid, acetylcysteine, cysteine, arginine, lysine, glutamic acid, etc. In the embodiments and comparative examples of the present application, the chiral ligand is penicillamine, and the corresponding examples and technical steps and technical effects are described. The other chiral ligands mentioned above can also achieve the same technical effects as penicillamine, which will not be repeated here.

[0045] As an optional embodiment, the prefabricated chiral ligand in step S3 may be a D-penicillamine ligand or an L-penicillamine ligand.

[0046] S4: Cleaning the preset glass sheet coated with the conductive material using ethanol, and removing the remaining ethanol after cleaning to obtain a prefabricated substrate.

[0047] Optionally, after obtaining the prefabricated substrate, an air gun may be used to blow dry the prefabricated substrate.

[0048] S5: spin-coating the first solution and the second solution onto the prefabricated substrate in sequence according to a preset number of layers to obtain a chiral quantum dot film, and performing annealing treatment to obtain a target chiral photoconductive device.

[0049] After the treatment in step S5, a L / D-penicillamine lead sulfide quantum dot film can be obtained, that is, a D-penicillamine lead sulfide quantum dot film and an L-penicillamine lead sulfide quantum dot film can be obtained.

[0050] The preset number of layers can be set to five or nine.

[0051] As a preferred embodiment, the step of spin coating the first solution and the second solution onto the prefabricated substrate and performing annealing in the above step S5 may specifically include the following steps:

[0052] Step 1: vacuum adsorb the prefabricated substrate by a glue spreader, and set the rotation speed of the glue spreader to a first rotation speed. For example, the first rotation speed of the glue spreader may be 4000 rpm.

[0053] Step 2: Spin-coat a first volume of the first solution onto the prefabricated substrate on a spin coater for a first time to obtain a first quantum dot film.

[0054] As a preferred implementation, the first time of the spin coating is set to 30 seconds.

[0055] Step 3: Take a second volume of the second solution and drop it on the first quantum dot film for a second time, then drive the coating machine at a second speed for a third time to remove the remaining second solution. For example, the second speed of the coating machine can be 3000 rpm, and the third time can be 10 seconds.

[0056] As another preferred implementation, the second silent time is set to 30 seconds.

[0057] As an example, in step S52 , the first volume of the first solution spin-coated may be 40 μl, and 500 μl of the second solution may be dropped on the first quantum dot film.

[0058] Step 4: Drive the coating machine and use methanol reagent to clean the first quantum dot film on the coating machine to obtain a single-layer chiral quantum dot film. For example, a single-layer L / D-penicillamine lead sulfide quantum dot film, that is, a single-layer D-penicillamine lead sulfide quantum dot film and a single-layer L-penicillamine lead sulfide quantum dot film can be obtained.

[0059] Please continue reading Figure 2 , Figure 3 , Figure 4 and Figure 5 , Figure 2 is a UV-visible absorption spectrum of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the embodiment of the present application in the range of 200 nanometers to 800 nanometers, Figure 3 is a circular dichroism spectrum of a D-penicillamine lead sulfide quantum dot film and an L-penicillamine lead sulfide quantum dot film in the range of 200 nanometers to 800 nanometers provided in the examples of the present application, Figure 4 is a UV-visible absorption spectrum of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the embodiment of the present application in the range of 800 nanometers to 1600 nanometers, Figure 5The circular dichroism spectra of the D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film provided in the embodiment of the present application in the range of 800 nanometers to 1600 nanometers, wherein the horizontal axis in the ultraviolet visible absorption spectrum is the wavelength and the vertical axis is the absorbance, and the horizontal axis in the circular dichroism spectrum is the wavelength of the plane polarized light and the vertical axis is the difference between the absorption coefficients of the left and right circularly polarized light. The D-penicillamine lead sulfide quantum dot film and the L-penicillamine lead sulfide quantum dot film both show strong circular dichroism (CD) signals in the visible light region and the short-wave infrared region, indicating that the chiral quantum dot film is successfully composited. The chiral active centers of the L-penicillamine lead sulfide quantum dot film and the D-penicillamine lead sulfide quantum dot film appear at around 1100nm, and show completely opposite CD active signals, with a CD value of 7.35mdeg, and high CD helps to improve the recognition ability of circularly polarized light photodetectors to circularly polarized light.

[0060] Step 5: Continue to repeatedly spin-coat the first volume of the first solution and the second volume of the second solution onto the newly obtained single-layer chiral quantum dot film until the number of spin coating times is equal to the preset number of layers, thereby obtaining a multi-layer chiral quantum dot film.

[0061] Step 6: Annealing the multilayer quantum dot film in an environment of 85° C. for 10 minutes to obtain the target chiral photoconductive device.

[0062] The embodiment of the present application also provides a chiral photoconductive device, which is obtained according to the above-mentioned chiral photoconductive device preparation method.

[0063] An embodiment of the present application also provides a chiral photodetector, which includes the chiral photoconductive device mentioned above.

[0064] Comparative Example 1

[0065] Comparative Example 1 provides a method for preparing a chiral photoconductive device. The difference from Example 1 is that in the step of spin coating the lead sulfide quantum dot solution in Comparative Example 1, the preset number of layers is fixed to nine layers, and nine layers of L-penicillamine-lead sulfide quantum dot photoconductive devices and nine layers of D-penicillamine-lead sulfide quantum dot photoconductive devices are obtained respectively.

[0066] Among them, one of the basic principles of photodetectors is to use the photoconductivity effect, that is, when light irradiates a semiconductor material, when the energy of the photon is equal to or greater than the semiconductor bandgap width, the electrons in the valence band will jump to the conduction band, generating electron-hole pairs, which increases the carrier concentration inside the semiconductor, thereby increasing the conductivity of the material. At the same time, under the action of an external electric field, the photogenerated carriers move in a directional manner, thereby generating a photocurrent that can be detected externally.

[0067] Then, under the same light power, polarized light was used to test the effects of the nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device and the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device under the photocurrent (Light) and dark current (Dark), and the responsiveness of the nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device and the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device was tested.

[0068] Please continue reading Figure 6 and Figure 7 , Figure 6 is a graph showing the relationship between the photocurrent and dark current of a nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with left-handed circularly polarized light as a function of voltage. Figure 7 : is a graph showing the relationship between the photocurrent and dark current of the nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage. Figure 6 and Figure 7 As shown, the light-dark separation of the device irradiated with right-handed circularly polarized light is more obvious, reaching 7.36 μA under left-handed circularly polarized light and 16.98 μA under right-handed circularly polarized light.

[0069] Please continue reading Figure 8 and Fig. 9 , Figure 8 is a graph showing the relationship between the photocurrent and dark current of a nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application under left-handed circularly polarized light and the change in voltage. Fig. 9 : is a graph showing the relationship between the photocurrent and dark current of the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage. Figure 8 and Fig. 9 As shown, the light-dark separation of the device irradiated with left-handed circularly polarized light is more obvious, reaching 14.16 μA under left-handed circularly polarized light, and the light-dark separation under right-handed circularly polarized light reaches 5.55 μA.

[0070] Please continue reading Fig.10 and Fig.11 , Fig.10 This is a graph showing the responsiveness test results of a nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application. Fig.11 This is a graph of the response test results of the nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application, wherein the horizontal axis represents voltage and the vertical axis represents the response corresponding to light of different rotational properties.

[0071] Comparative Example 2

[0072] Comparative Example 2 provides a method for preparing a chiral photoconductive device. The difference from Example 1 is that in the step of spin coating the lead sulfide quantum dot solution in Comparative Example 2, the preset number of layers is fixed to five layers, and a five-layer L-penicillamine-lead sulfide quantum dot photoconductive device and a five-layer D-penicillamine-lead sulfide quantum dot photoconductive device are obtained respectively.

[0073] Then, under the same light power, polarized light was used to test the effects of the five-layer L-penicillamine-lead sulfide quantum dot photoconductive device and the five-layer D-penicillamine-lead sulfide quantum dot photoconductive device on photocurrent (Light) and dark current (Dark).

[0074] Please continue reading Fig.12 and Fig.13 , Fig.12 is a graph showing the relationship between the photocurrent and dark current of a five-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with left-handed circularly polarized light as a function of voltage. Fig.13 : is a graph showing the relationship between the photocurrent and dark current of the five-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in the embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage. Fig.12 and Fig.13 As shown, the light-dark separation of the device irradiated with right-handed circularly polarized light is more obvious, reaching 0.88 μA under left-handed circularly polarized light and 5.58 μA under right-handed circularly polarized light.

[0075] Please continue reading Fig.14 and 15 , Fig.14 is a graph showing the relationship between the photocurrent and dark current of a five-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with left-handed circularly polarized light as a function of voltage. Fig.15 : is a graph showing the relationship between the photocurrent and dark current of a five-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application when irradiated with right-handed circularly polarized light as a function of voltage. Fig.14 and Fig.15 As shown, the light-dark separation of the device irradiated with left-handed circularly polarized light is more obvious, reaching 4.47 μA under left-handed circularly polarized light, and the light-dark separation under right-handed circularly polarized light reaches 0.35 μA.

[0076] Please continue reading Fig.16 and Fig.17 , Fig.16 This is a graph showing the responsiveness test results of a five-layer L-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application. Fig.17 This is a graph showing the responsiveness test results of a five-layer D-penicillamine-lead sulfide quantum dot photoconductive device provided in an embodiment of the present application.

[0077] Comprehensive comparative example 1 Figure 6 , Figure 7 , Figure 8 and Fig. 9 , and in Comparative Example 2 Fig.12 , Fig.13 , Fig.14 and Fig.15 It can be seen that the five-layer spin-coated L-penicillamine-lead sulfide quantum dot photoconductive device and the D-penicillamine-lead sulfide quantum dot photoconductive device have low discrimination for circularly polarized light of different handedness (left-handed and right-handed). Fig.10 and Fig.11 , Comparative Example 2 Fig.16 and Fig.17 It can be seen that the five-layer spin-coated L-penicillamine-lead sulfide quantum dot photoconductive device and D-penicillamine-lead sulfide quantum dot photoconductive device have low responsiveness to circularly polarized light of different handedness (left-handed and right-handed). Therefore, in order to obtain a chiral photoconductive device or a chiral photodetector with high circularly polarized light discrimination, high responsiveness and high circularly polarized light detection performance, when executing the chiral photoconductive device preparation method proposed in the embodiment of the present application, the number of spin-coated layers can be set to nine layers to obtain a nine-layer L-penicillamine-lead sulfide quantum dot photoconductive device and a nine-layer D-penicillamine-lead sulfide quantum dot photoconductive device, and further obtain the corresponding chiral photodetector.

[0078] The chiral photoconductive device preparation method provided in the embodiment of the present application obtains chiral inorganic material penicillamine-lead sulfide quantum dots by simple ligand exchange between lead sulfide quantum dots and chiral penicillamine ligands, and uses the chiral inorganic material-penicillamine-lead sulfide quantum dots to prepare the corresponding chiral photoconductive device, which has good light-dark separation effect and high responsiveness, and has different absorption of left-handed circularly polarized light and right-handed circularly polarized light, and has high discrimination degree for circularly polarized light of different handedness, can realize circularly polarized light detection in the short-wave infrared band range, and also has excellent performances of high photoelectric anisotropy, excellent photoelectric performance, high stability and good repeatability.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a chiral photoconductive device, characterized in that: include: Preparation of lead sulfide quantum dots; Dissolving the lead sulfide quantum dots in n-octane to obtain a first solution, wherein the concentration of the lead sulfide quantum dots in the first solution is 50 mg / ml; dissolving the preformed chiral ligand in methanol to obtain a second solution, wherein the concentration of the chiral ligand in the second solution is 5 mg / ml; Using ethanol to clean a preset glass sheet coated with a conductive material, and removing the remaining ethanol after cleaning to obtain a prefabricated substrate; The first solution and the second solution are sequentially spin-coated onto the prefabricated substrate according to a preset number of layers, and annealed to obtain a target chiral photoconductive device.

2. The method for preparing a chiral photoconductive device according to claim 1, characterized in that: The step of preparing lead sulfide quantum dots comprises: preparing a lead source precursor; Evenly mixing 2.7 mL of 1-octadecene and 0.3 mL of hexamethyldisilathione to obtain the prefabricated sulfur source; Passing nitrogen into the lead source precursor, and injecting a prefabricated sulfur source when the reaction temperature drops to 100° C. to obtain a lead sulfide quantum dot stock solution; Adding n-hexane and acetone to the lead sulfide quantum dot stock solution, and stirring at a speed of 7000 rpm for 3 minutes to obtain a fourth solution; The fourth solution is washed 2 or 3 times, the clear solution after washing is removed, and then dried to obtain the lead sulfide quantum dots.

3. The method for preparing a chiral photoconductive device according to claim 2, characterized in that: The step of preparing the lead source precursor comprises: 0.45 g of lead oxide and 12 ml of 1-octadecene were added to 8 ml of oleic acid to obtain a third solution; The third solution was heated to 40° C. under a nitrogen atmosphere, and the third solution was stirred at a speed of 500 rpm; The third solution is transferred to a continuously vacuumed environment, and the third solution is heated to 120° C. and maintained for at least 2 hours to obtain the lead source precursor.

4. The method for preparing a chiral photoconductive device according to claim 1, characterized in that: The step of spin coating the first solution and the second solution onto the prefabricated substrate and performing annealing treatment comprises: The prefabricated substrate is vacuum-adsorbed by a glue spreader, and the rotation speed of the glue spreader is set to a first rotation speed; Spin coating a first volume of the first solution onto the prefabricated substrate on a spin coater for a first time to obtain a first quantum dot film; Taking a second volume of the second solution and dropping it on the first quantum dot film and leaving it there for a second time, then driving the coating machine at a second speed for a third time to remove the remaining second solution; Driving a coating machine and using a methanol reagent to clean the first quantum dot film on the coating machine to obtain a single-layer chiral quantum dot film; Standing for one minute, continuing to repeatedly spin-coat the first volume of the first solution and the second volume of the second solution onto the newly obtained single-layer quantum dot film until the number of spin-coating times equals the preset number of layers, thereby obtaining a multi-layer chiral quantum dot film; The multilayer chiral quantum dot film is annealed for 10 minutes in an environment of 85° C. to obtain the target chiral photoconductive device.

5. The method for preparing a chiral photoconductive device according to claim 1, characterized in that: The chiral ligand is a D-chiral ligand or an L-chiral ligand; the preset number of layers is five or nine.

6. The method for preparing a chiral photoconductive device according to claim 4, characterized in that: The first rotation speed of the glue spreader is 4000 rpm, and the second rotation speed is 3000 rpm.

7. The method for preparing a chiral photoconductive device according to claim 4, characterized in that: The first time that the coating machine is spin-coated is 30 seconds, the second time that the silent process lasts is 30 seconds, and the third time that the coating machine is driven is 10 seconds.

8. The method for preparing a chiral photoconductive device according to claim 4, characterized in that: The first volume of the first solution is 40 μl, and the second volume of the second solution is 500 μl.

9. A chiral photoconductive device, characterized in that: The chiral photoconductive device is prepared by the chiral photoconductive device preparation method according to claims 1 to 8.

10. A chiral photodetector, characterized in that: The chiral photodetector comprises the chiral photoconductive device according to claim 9.

Images