CN114784199A - Narrow-band optical detector with wide-angle detection imaging capability and preparation method thereof - Google Patents

Abstract

A narrow-band optical detector with wide-angle detection imaging capability and a preparation method thereof belong to the technical field of optical detection.The detector comprises a hemispherical substrate, an anode, a hole transport layer, a perovskite thin film, an electron transport layer, a buffer layer and a cathode, or comprises a hemispherical substrate, a cathode, an electron transport layer, a perovskite thin film, a hole transport layer and an anode, and the perovskite thin film PEA₂FA₃Pb₄X₁₃(X ═ Br, I, or Br and I) is an active material for absorbing photons. According to the invention, the quasi-two-dimensional perovskite film is deposited on the hemispherical substrate by introducing a solution spraying method, so that the optical detector has the characteristic of lens-free wide-angle response. The recombination capability at the surface short wave position is improved by controlling the thickness of the film and changing the proportion of phenylethylamine cations, and the narrow-band response of the optical detector under the condition of no filter is realized. The detector has low preparation cost and good narrow-band and wide-angle detection capability.

Description

A narrow-band photodetector with wide-angle detection imaging capability and preparation method thereof

technical field

The invention belongs to the technical field of light detection, and in particular relates to a narrow-band light detector with wide-angle detection and imaging capability and a preparation method thereof.

Background technique

Optical detection is widely used in many fields such as optical communication, medical treatment, national defense, and detection of distant galaxies, and optical detectors are one of the core technologies for realizing the above-mentioned optical detection applications. Therefore, the development of low-cost, color recognition, multi-angle perceptible spherical light detectors is an important research direction in the field of light detection technology.

Compared with the flat detector, the spherical detector has a wider spatial detection range, and also reduces the dependence of the detector on the optical lens. For traditional photodetection materials, it is generally considered difficult to realize the primary fabrication of devices on the surface of spheres due to their rigid structure and high temperature processing conditions. It is feasible to spray the perovskite precursor solution on the curved substrate to form a film by using the solution spraying method. At the same time, during the preparation process of the spray method, the extremely fast evaporation rate makes it difficult for the perovskite precursor droplets to dissolve during the crystallization process of the perovskite surface.

Quasi-2D perovskite materials have both organic cations with larger radii to hinder the flow of carriers and a bandgap that can be widely adjusted. A low-cost, narrow-band photodetector for wide-angle detection.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a narrow-band photodetector with wide-angle detection and imaging capability and a preparation method thereof. The photodetector has the advantages of wide spatial detection range, identifiable light color, and low cost.

The narrow-band photodetector with wide-angle detection and imaging capability of the present invention, from bottom to top, is composed of a hemispherical substrate, an anode, a hole transport layer, a perovskite film, an electron transport layer, a buffer layer and a cathode, or is composed of a hemispherical substrate , cathode, electron transport layer, perovskite film, hole transport layer and anode composition, phenethylamine formamidine lead halogen PEA ₂ FA ₃ Pb ₄ X ₁₃ (X=Br, I) perovskite film for absorption Photonic active material.

The preparation method of a narrow-band photodetector (hemispherical substrate, anode, hole transport layer, perovskite film, electron transport layer, buffer layer, cathode) with wide-angle detection and imaging capability according to the present invention is shown in FIG. 1 . shown, the steps are as follows:

(1) Select a hemispherical substrate with a diameter of 0.8 to 2 cm (the material is ordinary glass, which can be obtained from commercial channels), ultrasonically clean it in ultrapure water, acetone and isopropanol for 10 to 20 minutes, and then dry;

(2) Evaporating metal Cr onto the surface of the hemispherical substrate as an anode by vacuum evaporation, with a thickness of 8-15 nm, and then performing ultraviolet-ozone treatment on the surface of metal Cr for 15-30 minutes, and then performing plasma treatment for 5-10 minutes;

(3) Deposit a hole transport layer on the anode surface

(a) Dilute the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) aqueous solution with ultrapure water to obtain a PEDOT:PSS concentration of 0.05-0.2%wt. hole transport layer solution;

(b) adding 400-1000 μL of the hole transport layer solution in step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) place the hemispherical substrate with the anode prepared on the surface on a hot stage at 60-80°C, connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1-3 MPa, and the spraying rate is 0.10-0.3 mL /min, spray the hole transport layer solution on the surface of the anode, during the spraying process, keep the rotation and translation of the hemispherical substrate, the rotation speed is 0.20~0.30r/min, and the translation speed is 5~20cm/s, so as to keep the spraying The flatness of the film; in the process of spraying, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with high-speed nitrogen of 4-7MPa to form a relatively dry film; when the solution is exhausted, the film is removed. Annealing at 160-180°C for 20-40 minutes, thereby obtaining a hole transport layer with a thickness of 10-100 nm on the anode surface;

(4) Deposition of PEA ₂ FA ₃ Pb ₄ X ₁₃ (X=Br, I or Br and I, the sum of the subscripts is 13) perovskite thin film on the surface of the hole transport layer

(a) Formamidine hydrohalide (FAX), lead halide (PbX ₂ ), phenethylamine hydrohalide (PEAX) and methylamine hydrochloride (MAC1) were prepared according to PEA ₂ FA ₃ Pb ₄ X ₁₃ ( The molecular formula ratio of X=Br,I) is configured as a precursor solution with a lead ion concentration of 0.4-0.6M, and the solvent is a mixed solvent of acetonitrile (ACN) and N,N-dimethylformamide (DMF), or ethylene di Mixed solvent of alcohol methyl ether (2-Me) and N,N-dimethylformamide (DMF), acetonitrile (ACN) or ethylene glycol methyl ether (2-Me) and N,N-dimethylformamide The volume ratio of (DMF) is 1:1 to 3. By adjusting the dosage ratio of N,N-dimethylformamide (DMF), the solubility of the precursor can be improved, so that the perovskite powder can be completely dissolved;

(b) adding 500-2000 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) Place the hemispherical substrate with the hole transport layer deposited on the surface on a heating table at 80-120°C, connect the pneumatic spray gun in step (b) to an air compressor with an output pressure of 1-3 MPa, and the spraying rate is 0.1 ～0.3mL/min, spray the precursor solution on the surface of the hole transport layer; during the spraying process, keep the rotation and translation of the hemispherical substrate, the rotation speed is 0.20～0.30r/min, and the translation speed is 5～20cm/s , so as to maintain the flatness of the sprayed film; in the process of spraying, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with high-speed nitrogen of 4-7MPa to form a relatively dry film;

(d) annealing the hemispherical substrate obtained in step (c) at 80-120°C for 8-15 minutes, then annealing at 120-140°C for 20-40 minutes, and finally annealing at 160-170°C for 60-90 minutes, Dark conditions are maintained during the annealing process to obtain perovskite films with a thickness of 2-40 μm;

(5) Evaporating the purchased fullerene (C ₆₀ ) onto the surface of the perovskite thin film by vacuum evaporation to obtain an electron transport layer with a thickness of 15-30 nm;

(6) The purchased 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) was evaporated to the surface of the electron transport layer by vacuum evaporation to obtain a thickness of 4-10 nm the buffer layer;

(7) Evaporating metal Cr onto the surface of the buffer layer as a cathode by vacuum evaporation, with a thickness of 8-15 nm; thereby preparing the narrow-band photodetector with wide-angle detection and imaging capability according to the present invention, the structure is hemispherical substrate/Cr/PEDOT : PSS/PEA ₂ FA ₃ Pb ₄ X ₁₃ /C ₆₀ /BCP/Cr.

The preparation method of the second device structure (hemispherical substrate, cathode, electron transport layer, perovskite film, hole transport layer, anode) of the present invention comprises the following steps:

(1) Select a hemispherical substrate with a diameter of 0.8 to 2 cm (the material is ordinary glass, which can be obtained from commercial channels), ultrasonically clean it in ultrapure water, acetone and isopropanol for 10 to 20 minutes, and then dry;

(2) Evaporating metal Cr onto the surface of the hemispherical substrate as a cathode by vacuum evaporation, with a thickness of 8-15 nm, and then performing UV-ozone treatment on the surface of metal Cr for 15-30 minutes, and then performing plasma treatment for 5-10 minutes;

(3) Deposition of an electron transport layer on the surface of the cathode

(a) Dilute the purchased SnO ₂ aqueous solution with ultrapure water to prepare an electron transport layer solution with SnO ₂ concentration of 0.05-0.1%wt;

(b) adding 400-1000 μL of the electron transport layer solution obtained in step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) placing the hemispherical substrate with the cathode prepared on the surface on a heating table at 60-80°C, and connecting the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1-3 MPa, and the spraying rate is 0.10-0.20 mL /min, spray the electron transport layer solution on the surface of the cathode; during the spraying process, keep the rotation and translation of the hemispherical substrate, the rotation speed is 0.20~0.30r/min, and the translation speed is 5~20cm/s, so as to keep the sprayed film In the process of spraying, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with high-speed nitrogen of 4-7MPa to form a relatively dry film; when the solution is exhausted, the film is placed in Annealing at 160-180°C for 20-40 minutes, and then performing UV-ozone treatment for 15-30 minutes, thereby obtaining an electron transport layer with a thickness of 10-100 nm on the surface of the cathode;

(4) Deposition of PEA ₂ FA ₃ Pb ₄ X ₁₃ (X=Br, I or Br and I, the sum of the subscripts is 13) perovskite thin film on the surface of the electron transport layer

(a) Formamidine hydrohalide (FAX), lead halide (PbX ₂ ), phenethylamine hydrohalide (PEAX) and methylamine hydrochloride (MAC1) were prepared according to PEA ₂ FA ₃ Pb ₄ X ₁₃ ( The molecular formula ratio of X=Br,I) is configured as a precursor solution with a lead ion concentration of 0.4-0.6M, and the solvent is a mixed solvent of acetonitrile (ACN) and N,N-dimethylformamide (DMF), or ethylene di Mixed solvent of alcohol methyl ether (2-Me) and DMF, the volume ratio of acetonitrile (ACN) or ethylene glycol methyl ether (2-Me) to N,N-dimethylformamide (DMF) is 1:1～ 3. By adjusting the dosage ratio of N,N-dimethylformamide (DMF), the solubility of the precursor can be improved, so that the perovskite powder can be completely dissolved;

(b) adding 500-2000 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) placing the hemispherical substrate with the electron transport layer deposited on the surface on a heating table at 80-120°C, connecting the pneumatic spray gun in step (b) to an air compressor with an output pressure of 1-3 MPa, and a spraying rate of 0.1-3 MPa. 0.3mL/min, spray the precursor solution on the surface of the electron transport layer; during the spraying process, keep the rotation and translation of the hemispherical substrate, the rotation speed is 0.20~0.30r/min, and the translation speed is 5~20cm/s, thus Maintain the flatness of the sprayed film; in the process of spraying, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with high-speed nitrogen of 4-7MPa to form a dry film;

(d) annealing the hemispherical substrate obtained in step (c) at 80-120°C for 8-15 minutes, then annealing at 120-140°C for 20-40 minutes, and finally annealing at 160-170°C for 60-90 minutes, Dark conditions are maintained during the annealing process; thus a perovskite film with a thickness of 2-40 μm is obtained;

(5) depositing a hole transport layer on the surface of the perovskite thin film, the steps are as follows:

(a) The purchased poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) was prepared with toluene to form a hole transport layer with a PTAA concentration of 0.05-0.2 mg/mL solution;

(b) adding 400-1000 μL of the hole transport layer solution obtained in step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) Fix the hemispherical substrate with the perovskite film on the surface on a heating table at 60-80 °C, and connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1-3 MPa, and the spraying rate is 0.10 ～0.20mL/min, spray the hole transport layer solution on the perovskite film, during the spraying process, keep the rotation and translation of the hemispherical substrate, the rotation speed is 0.20～0.30r/min, and the translation speed is 5～20cm/ s, so as to maintain the flatness of the sprayed film; in the process of spraying, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with high-speed nitrogen of 4-7MPa to form a relatively dry film; when the solution is consumed After finishing, the film is annealed at 90-110° C. for 5-15 minutes to obtain a hole transport layer with a thickness of 10-100 nm;

(6) Evaporating metal Cr onto the surface of the hole transport layer as an anode by vacuum evaporation, with a thickness of 8-15 nm, thereby preparing the narrow-band photodetector with wide-angle detection and imaging capability according to the present invention, the structure is hemispherical substrate/Cr /SnO ₂ /PEA ₂ FA ₃ Pb ₄ X ₁₃ /PTAA/Cr.

The imaging method of a narrow-band photodetector with wide-angle detection imaging capability according to the present invention, the steps are as follows:

(a) Fix a monochromatic LED light source whose center wavelength is 400-900nm adjustable on the X-Y two-dimensional displacement platform, and the light source power is 3-10W;

(b) connecting the X-Y two-dimensional displacement platform in step (a) to a computer to control its movement, and the moving unit distance is 200-500 μm/step;

(c) connecting the LED light source in the step (a) to a function generator (the model is Puyuan RIGOL DG1022Z), and the function generator outputs a square wave signal with a frequency of 20 to 90 Hz;

(d) placing the object to be measured (swan-shaped hairpin) on the glass platform under the LED light source, and placing the hemispherical narrow-band light detector prepared by the present invention under the glass platform;

(e) Adjust the angle of the hemispherical narrow-band photodetector described in step (d) so that it presents a certain angle with the imaging system (the angle (ξ) between the incident light direction and the normal to the bottom surface of the hemispherical photodetector) , the hemispherical detector can be used to change the ξ angle by rotating along the center of the sphere to control the imaging of the detector at various angles, ξ=0°～90°), and then connect the hemispherical narrow-band photodetector to the preamplifier, lock Phase amplifier and computer; in the experiment, the function generator outputs a square wave signal to the light source and the same frequency as the lock-in amplifier, the device receives the optical signal and converts it into a current signal and outputs it to the preamplifier, and the preamplifier converts the current signal into The voltage signal is amplified and transmitted to the lock-in amplifier, and the lock-in amplifier further amplifies the voltage information from the same frequency signal of the preamplifier and the function generator and transmits it to the computer. Each time the stepper motor moves one step, a data point is read, forming a data matrix.

(f) The voltage data matrix is read by a computer, and the imaging results are finally obtained by MATLAB software.

Compared with the prior art, a narrow-band photodetector with wide-angle detection capability and a preparation method thereof provided by the present invention have the following advantages:

The photodetector of the present invention attaches the perovskite precursor on the spherical substrate through a spraying method, and thus a low-cost ultra-wide-angle photodetector without a lens is manufactured at low cost.

The photodetector of the present invention controls the adhesion of the perovskite precursor to the spherical substrate through the spraying method, the thickness of the perovskite is reasonably controlled, and the composite surface carriers can be realized without the existence of a filter, and the single wavelength can be realized. The ability to respond, its narrowband response reaches a full width at half maximum of ~20nm.

The quasi-two-dimensional perovskite film (PEA ₂ FA ₃ Pb ₄ X ₁₃ ) in the present invention is used as the active material. On the one hand, the large-volume cations can effectively recombine the carriers generated by the short wavelength on the surface and improve the perovskite performance. Stability; on the other hand, the addition of three-dimensional perovskites improves the adjustable detection range of narrow-band detectors.

Description of drawings

Figure 1 is a schematic diagram of the process of preparing a PEA ₂ FA ₃ Pb ₄ X ₁₃ perovskite film on a hemispherical substrate; it is divided into spraying, nitrogen-assisted film formation, deposition cycle, thermal annealing and other steps. As shown in the figure, the precursor solution was sprayed onto the surface of the hemispherical substrate by a pneumatic spray gun, and quickly formed into a film and dried under the action of nitrogen pressure; after drying, the precursor solution was sprayed onto the surface of the hemispherical surface for cyclic deposition; 80-120°C), thereby obtaining a PEA ₂ FA ₃ Pb ₄ X ₁₃ perovskite film on the surface of the hemispherical substrate.

Figure 2(a) is the optical photo of the prepared PEA ₂ FA ₃ Pb ₄ I ₁₃ perovskite film, which shows that the perovskite film formed by spraying has good film-forming properties and flatness; Figure (b) is PEA ₂ FA The X-ray powder diffraction (XRD) test results of the ₃ Pb ₄ X ₁₃ perovskite film show that the film exhibits excellent crystallinity.

3 is a schematic structural diagram of the photodetector according to the present invention; as shown in the figure, the present invention includes two device structures: one device structure is composed of a hemispherical substrate 7, an anode 6, a hole transport layer 2, a perovskite Thin film 1, electron transport layer 3, buffer layer 4 and cathode 5 are composed of, another device structure is composed of hemispherical substrate f, cathode d, electron transport layer c, perovskite film a, hole transport layer b and anode e .

Figure 4 (a) is a schematic diagram of a voltage-current density test system; in the figure, a light source with variable intensity is used to irradiate the device prepared by the present invention, the current source meter is connected to the positive and negative electrodes of the device, and then the current source meter is connected to a computer to measure Different voltages, the current density of the device under different light intensities when the voltage is applied between the positive and negative electrodes of the device, and plotted as a curve.

Figure 4(b) shows the voltage-current density curves of the hemispherical substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr photodetector under different illumination intensities; the results show that the device performs well The low dark current and photo-generated voltage phenomenon indicate that the device has low noise and can work with self-powered power.

Figure 5(a) is a schematic diagram of the optical switch signal test system; in the figure, the signal generator gives a square wave signal to trigger the light source, and the light source outputs the square wave signal to the surface of the device; the device converts the collected optical signal into an electrical signal and outputs it to the oscilloscope , producing a square wave image; 820 nm and 532 nm light sources were used, respectively, with light intensities of 0.72 mW/cm ² and 2.17 mW/cm ² , respectively.

Figure 5(b) is the square wave signal diagram of the hemispherical substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr photodetector triggered by different wavelengths of light; the device in the figure is at 820nm Under the illumination of 532nm light, there is an obvious square wave signal; under the illumination of 532nm light, there is no obvious signal. The results show that the device can specifically recognize light with a wavelength of 820 nm, but has almost no response to light of 532 nm, which indicates that the narrow-band response of the device is remarkable.

Figure 6(a) is a schematic diagram of the device's wide-angle detection capability testing system; in the figure, the position of the light source is variable, which is used to adjust the angle of the incident light. generated electrical signal.

Fig. 6(b) The angular response range curve of the hemispherical or planar substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr photodetector; the abscissa is the detection angle, and the ordinate is The normalized photocurrent magnitude; the results show that the hemispherical and planar photodetectors have different responsiveness to incident light at different angles, and the hemispherical photodetector exhibits a very high wide-angle detection capability.

Figure 7(a) is a schematic diagram of the device's narrow-band detection capability testing system; it is measured by external quantum efficiency (EQE). on the detector. The current signal generated by the detector is amplified by the preamplifier and converted into a voltage signal, and the same-frequency signal is amplified again by the lock-in amplifier and input to the computer to calculate the difference between the current density generated by the detector and the photon density irradiated on the detector. ratio to calculate the quantum efficiency.

Figure 7(b) is a graph of the narrowband detection capability of light detectors with different structures; the abscissa is the wavelength, the ordinate is the normalized external quantum efficiency (EQE), and the device structure of the 550nm response is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₃ /PTAA/Cr, the device structure of 600nm response is hemispherical substrate /Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₁ I ₂ /PTAA/Cr, the device structure of 660nm response is hemisphere Substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₈ I ₅ /PTAA/Cr, the device structure of 820nm response is hemispherical substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP /Cr. The figure shows that we can successfully tune the position of the response center wavelength of the narrowband detector by changing the relative ratio of I and Br in halogen X. At the same time, its EQE at different wavelengths shows the characteristic of only responding near the central wavelength. In other positions, the EQE is very low, indicating that the detector has almost no response to light of other wavelengths, which reflects the nature of narrow-band detection by narrow-band detectors.

Figure 8 is a schematic diagram of the prepared photodetector imaging system; the function generator is connected to a monochromatic light source, the function generator outputs a square wave signal to the monochromatic light source and has the same frequency as the lock-in amplifier, the device receives the optical signal and converts it into a current signal and outputs it to In the preamplifier, the preamplifier converts the current signal into a voltage signal and amplifies it and transmits it to the lock-in amplifier. The lock-in amplifier further amplifies the voltage information from the same frequency signal of the preamplifier and the function generator and transmits it to the computer. Each time the stepper motor moves one step, a data point is read, forming a data matrix.

FIG. 9 shows a schematic diagram of the specific system of imaging and the relationship with the angle. The light source in the figure is a movable light source, which is driven by the displacement stage to move. During the specific imaging, the relative position of the object and the detector remains unchanged. After the imaging system is built, the angle of the detector can be rotated (ξ is the angle between the normal line of the hemispherical base and the normal line of the glass platform on which the object to be imaged is placed, It can be changed from -90° to 90°) and the position of the object can be adjusted to change the range of the start angle (θ ₁ ) and end angle (θ ₂ ) of the object imaging. Figure (a) shows a schematic diagram of the relative position of the angular range occupied by the object and the device when the angle is 0 degrees (ξ=0°). Figure (b) shows a schematic diagram of the relative position of the angular range occupied by the object and the device when the angle is -90 degrees (ξ=-90°).

Figure 10. Imaging schematic diagrams of objects occupying different imaging angles (from -52 degrees to -90 degrees and from -8 degrees to +30 degrees); because the detector is an axisymmetric structure, the sign is used to indicate the detection of the symmetrical orientation of the device imaging capabilities.

Figure 11 shows the imaging results of the prepared hemispherical photodetector and the plane photodetector; Figure 11(a) The imaging results of the plane photodetector, the angle occupied by the object is from -8 degrees to +30 degrees; Figure 11(b) The imaging result of the plane light detector, the angle occupied by the object is from -90 degrees to -52 degrees; Figure 11(c) The imaging result of the hemispherical light detector, the angle occupied by the object is from -8 degrees to +30 degrees; Figure 11 (d) The imaging result of the hemispherical photodetector, the angle occupied by the object is from -90 degrees to -52 degrees. It is explained here that the imaging ability of spherical light detectors for various angles is better than that of plane detectors. Especially for glancing angle (-90 degree) imaging, the plane detector has almost no signal, while the hemispherical detector can still maintain the imaging effect. It shows that the hemispherical detector prepared by spraying method has good wide-angle detection ability.

Fig. 12 Imaging results of hemispherical photodetectors with different structures under different monochromatic light; Fig. 12(a) is 550 nm monochromatic light, and the imaging device structure is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₃ / PTAA/Cr, Figure 12(b) is 600nm monochromatic light, the imaging device structure is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₂ Br ₁₁ /PTAA/Cr, Figure 12(c) is 660nm monochromatic light Color light, the imaging device structure is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₅ Br ₈ /PTAA/Cr, Fig. 12(d) is the superimposed image of the above-mentioned different monochromatic light imaging results. This imaging can represent objects more realistically, and each monochrome image can provide great help for post-image processing.

Detailed ways

Example 1: Structural characterization of the prepared perovskite thin films

(a) Formamidine hydrohalide (FAI), lead halide (PbI ₂ ), phenethylamine hydrohalide (PEAI) and methylamine hydrochloride (MACl) are in a ratio of 3:4: 2:1.2 is configured as a precursor solution of 0.6M (relative to lead ions), the solvent is acetonitrile (ACN) and N,N-dimethylformamide (DMF), and the solvent volume ratio is 1:1. The titanium ore powder is completely dissolved.

(b) adding 2000 μL of the precursor solution prepared in step (a) to a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2;

(c) The surface-modified hemispherical substrate was placed on a heating table at 100 °C, and the pneumatic spray gun in step (b) was connected to an air compressor with an output pressure of 1.7 MPa. The spraying time was determined by the total spraying volume. The spraying rate was 0.13 mL/min, sprayed onto the hemispherical substrate, and a wet perovskite film was obtained on the outer surface of the hemisphere; during the spraying process, the rotation and translation of the hemispherical substrate were maintained, the rotation speed was 0.25r/min, and the translational speed was In the process of spraying, after each droplet of the solution completely covers the hemispherical surface, the entire hemispherical surface is purged with 5MPa high-speed nitrogen gas to form a relatively dry film;

(d) The hemispherical substrate sprayed with the wet perovskite film obtained in step (c) was annealed at 120°C for 10 minutes, then annealed at 160°C for 30 minutes, and finally annealed at 170°C for 60 minutes, maintaining during the annealing process Under dark conditions, the thickness of the finally obtained perovskite film is 25 μm; the molecular formula of perovskite is PEA ₂ FA ₃ Pb ₄ I ₁₃ .

FIG. 2 is an optical photograph (a) and an XRD pattern (b) of the prepared PEA ₂ FA ₃ Pb ₄ I ₁₃ perovskite film, and the film shows excellent crystallinity.

Example 2:

1. The hemispherical substrate (made of ordinary glass, with a diameter of 0.8cm) was ultrasonically cleaned in ultrapure water, acetone, and isopropanol for 15 minutes each, and dried in an oven;

2. Evaporate metal Cr onto the surface of the hemispherical substrate as an anode by vacuum evaporation, with a thickness of 12 nm, and then perform ultraviolet-ozone treatment on the surface of metal Cr for 20 minutes, and then perform plasma treatment for 5 minutes;

3. The hole transport layer is deposited on the surface of the hemisphere, and the steps are as follows:

(a) Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) aqueous solution was diluted with ultrapure water to obtain hole transport with a PEDOT:PSS concentration of 0.1%wt layer solution;

(b) adding 800 μL of the hole transport layer solution in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) The hemispherical substrate with the anode prepared on the surface is placed on a hot stage at 65°C, the pneumatic spray gun in step (b) is connected to an air compressor, the output pressure is 1.7MPa, the spraying rate is 0.13mL/min, the air is The hole transport layer solution is sprayed onto the surface of the anode. During the spraying process, the rotation and translation of the hemispherical substrate are maintained. After each droplet of the solution completely covered the surface of the hemisphere, the entire surface of the hemisphere was purged with a high-speed nitrogen gas of 5 MPa to form a dry film; when the solution was exhausted, the film was annealed at 170 °C for 30 minutes, so that the anode surface A hole transport layer with a thickness of 10 nm was obtained;

4. The PEA ₂ FA ₃ Pb ₄ I ₁₃ perovskite film is deposited on the surface of the hole transport layer, and the steps are as follows:

(a) Formamidine hydrohalide (FAI), lead halide (PbI ₂ ), phenethylamine hydrohalide (PEAI) and methylamine hydrochloride (MACl) are in a ratio of 3:4: 2:1.2 The precursor solution solvent configured to be 0.6M (relative to lead ions) is a mixture of acetonitrile (ACN) and N,N-dimethylformamide (DMF), and the volume ratio is 1:1;

(b) adding 1500 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2;

(c) The hemispherical substrate with the hole transport layer deposited on the surface is placed on a heating stage at 100 °C, and the pneumatic spray gun in step (b) is connected to an air compressor with an output pressure of 1.7 MPa, and the spray rate is 0.13 mL /min sprayed onto the hemispherical substrate, and a wet perovskite film was obtained on the outer surface of the hemisphere; during the spraying process, the rotation and translation of the hemispherical substrate were maintained, the rotation speed was 0.25r/min, and the translational speed was 10cm/s, thereby To maintain the flatness of the sprayed film, the droplets of each solution completely cover the surface once, and the entire surface is purged with a high-speed nitrogen gas of 5MPa to form a relatively dry film on the surface;

(d) The hemispherical substrate sprayed with the wet perovskite film obtained in step (c) was annealed at 120°C for 10 minutes, then annealed at 140°C for 30 minutes, and finally annealed at 170°C for 60 minutes, maintaining during the annealing process Dark conditions, the resulting perovskite layer has a thickness of 12 μm

5. Evaporating the purchased fullerene (C ₆₀ ) onto the surface of the perovskite film by vacuum evaporation to obtain an electron transport layer with a thickness of 20 nm;

6. Evaporate the purchased 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) onto the surface of the electron transport layer by vacuum evaporation to obtain a buffer layer with a thickness of 6 nm ;

7. Evaporating metal Cr onto the surface of the buffer layer as a cathode by vacuum evaporation, with a thickness of 8 nm; thereby preparing the narrow-band photodetector with wide-angle detection and imaging capability according to the present invention, the structure is hemispherical substrate/Cr/PEDOT:PSS/ PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr.

Example 3:

1. The hemispherical substrate (made of ordinary glass, with a diameter of 0.8cm) was ultrasonically cleaned in ultrapure water, acetone, and isopropanol for 15 minutes each, and dried in an oven;

2. Evaporate metal Cr onto the surface of the hemispherical substrate as a cathode by vacuum evaporation, with a thickness of 15 nm, and then perform ultraviolet-ozone treatment on the surface of metal Cr for 20 minutes, and then perform plasma treatment for 5 minutes;

3. Deposition of an electron transport layer on the surface of the cathode

(a) Dilute the purchased _SnO aqueous solution with ultrapure water to prepare an electron transport layer solution with a _SnO concentration of 0.1% wt;

(b) adding 600 μL of the electron transport layer solution obtained in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) The hemispherical substrate with the cathode prepared on the surface is placed on a heating table at 70°C, and the pneumatic spray gun in step (b) is connected to an air compressor, the output pressure is 2MPa, and the spray rate is 0.12mL/min. The coating solution is sprayed onto the cathode surface; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, the rotation speed is 0.25r/min, and the translation speed is 15cm/s, so as to maintain the flatness of the sprayed film; during the spraying process, After each droplet of the solution completely covered the surface of the hemisphere, the entire surface of the hemisphere was purged with a high-speed nitrogen gas of 5MPa to form a relatively dry film; when the solution was exhausted, the film was annealed at 170 °C for 30 minutes, and then UV-ozone was carried out. Treated for 20 minutes to obtain an electron transport layer with a thickness of 10 nm on the surface of the cathode;

4. The PEA ₂ FA ₃ Pb ₄ Br ₁₃ perovskite film is deposited on the surface of the electron transport layer, and the steps are as follows:

(a) Formamidine hydrohalide (FABr), lead halide (PbBr ₂ ), phenethylamine hydrohalide (PEABr) and methylamine hydrochloride (MACl) are in a ratio of 3:4: 2:1.2 The precursor solution solvent configured to be 0.5M (relative to lead ions) is a mixture of acetonitrile (ACN) and N,N-dimethylformamide (DMF), and the volume ratio is 2:3;

(b) adding 1200 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2;

(c) place the hemispherical substrate with the electron transport layer deposited on the surface on a heating table at 100°C, connect the pneumatic spray gun in step (b) to an air compressor with an output pressure of 2MPa, and the spray rate is 0.15mL/min. The precursor solution is sprayed onto the surface of the electron transport layer; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, the rotation speed is 0.25r/min, and the translation speed is 10cm/s, so as to maintain the flatness of the sprayed film; During the process, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with a high-speed nitrogen gas of 5MPa to form a relatively dry film;

(d) The hemispherical substrate sprayed with the wet perovskite film obtained in step (c) was annealed at 120°C for 10 minutes, then annealed at 140°C for 30 minutes, and finally annealed at 170°C for 60 minutes, maintaining during the annealing process Dark conditions, the thickness of the perovskite film is 10 μm;

5. Deposit a hole transport layer on the surface of the perovskite film, the steps are as follows:

(a) The purchased poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) was prepared into a hole transport layer solution with a PTAA concentration of 0.1 mg/mL in toluene;

(b) adding 400 μL of the hole transport layer solution in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) Fix the hemispherical substrate with the perovskite film on the surface on a heating table at 80°C, and connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1.5MPa, and the spraying time is determined by the total spraying volume. . The spraying rate was 0.13 mL/min, sprayed onto the hemispherical substrate, and a wet perovskite film was obtained on the outer surface of the hemisphere; during the spraying process, the rotation and translation of the hemispherical substrate were maintained, the rotation speed was 0.25r/min, and the translational speed was 10cm/s, each droplet of the solution completely covers the surface once, and the entire surface is purged with a high-speed nitrogen gas of 5MPa to form a film with a relatively dry surface; when the solution is exhausted, the film hemisphere is annealed at 100 °C for 10 minutes, The thickness of the finally obtained hole transport layer is 10 nm;

6. Evaporating metal Cr onto the surface of the hole transport layer as an anode by vacuum evaporation, with a thickness of 8 nm, thereby preparing the narrow-band photodetector with wide-angle detection and imaging capability according to the present invention, the structure is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₃ /PTAA/Cr.

Example 4:

1. Select a hemispherical substrate with a diameter of 0.8cm (the material is ordinary glass, which can be obtained from commercial channels), ultrasonically clean it in ultrapure water, acetone and isopropanol for 15 minutes and then dry;

2. Evaporate metal Cr onto the surface of the hemispherical substrate as a cathode by vacuum evaporation, with a thickness of 13 nm, and then perform ultraviolet-ozone treatment on the surface of the metal Cr for 20 minutes, and then perform plasma treatment for 5 minutes;

3. Deposition of an electron transport layer on the surface of the cathode

(a) Dilute the purchased _SnO aqueous solution with ultrapure water to prepare an electron transport layer solution with a _SnO concentration of 0.1% wt;

(b) adding 600 μL of the electron transport layer solution obtained in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) Place the hemispherical substrate with the cathode prepared on the surface on a 65°C heating table, connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 2MPa, the spray rate is 0.12mL/min, and the electrons are transmitted The coating solution is sprayed onto the cathode surface; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, the rotation speed is 0.25r/min, and the translation speed is 15cm/s, so as to maintain the flatness of the sprayed film; during the spraying process, After each droplet of the solution completely covered the surface of the hemisphere, the entire surface of the hemisphere was purged with a high-speed nitrogen gas of 5MPa to form a relatively dry film; when the solution was exhausted, the film was annealed at 170 °C for 30 minutes, and then UV-ozone was carried out. Treated for 20 minutes to obtain an electron transport layer with a thickness of 10 nm on the surface of the cathode;

4. The PEA ₂ FA ₃ Pb ₄ I ₂ Br ₁₁ perovskite film is deposited on the surface of the electron transport layer, and the steps are as follows:

(a) Formamidine hydrohalide (FABr), lead halide (PbBr ₂ ), phenethylamine hydrohalide (PEAI) and methylamine hydrochloride (MACl) are in a ratio of 3:4: 2:1.2 is configured as a 0.5M (relative to lead ion) precursor solution, the solvent is a mixture of acetonitrile (ACN) and N,N-dimethylformamide (DMF), and the volume ratio is 2:3 to control the energy of the solution. Dissolve the perovskite powder completely;

(b) adding 1500 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2;

(c) place the hemispherical substrate with the electron transport layer deposited on the surface on a heating table at 100°C, connect the pneumatic spray gun in step (b) to an air compressor with an output pressure of 2MPa, and the spray rate is 0.15mL/min. The precursor solution is sprayed onto the surface of the electron transport layer; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, the rotation speed is 0.25r/min, and the translation speed is 10cm/s, so as to maintain the flatness of the sprayed film; During the process, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with a high-speed nitrogen gas of 5MPa to form a relatively dry film;

(d) The hemispherical substrate sprayed with the wet perovskite film obtained in step (c) was annealed at 120°C for 10 minutes, then annealed at 140°C for 30 minutes, and finally annealed at 170°C for 60 minutes, maintaining during the annealing process In dark conditions, a perovskite film with a thickness of 12 μm was finally obtained;

5. The hole transport layer is deposited on the surface of the perovskite film, and the steps are as follows:

(a) The purchased poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) was prepared into a hole transport layer solution with a PTAA concentration of 0.1 mg/mL in toluene;

(b) adding 400 μL of the hole transport layer solution obtained in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) Fix the perovskite-coated hemispherical substrate on a heating table at 80 °C, and connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1.5 MPa, and the spraying time is determined by the total spraying volume. The spraying rate is 0.13mL/min, sprayed onto the hemispherical substrate, and a wet perovskite film is obtained on the outer surface of the hemisphere; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, and the rotation speed is about 0.25r/min, The translation speed is 10cm/s, the droplets of each solution cover the surface completely, and the entire surface is blown with a high-speed nitrogen of 5MPa to form a film with a relatively dry surface; when the solution is exhausted, the hemisphere of the film is annealed at 100 °C 10 minutes, the thickness of the obtained hole transport layer is 10 nm;

6. Evaporating metal Cr onto the surface of the hole transport layer as an anode by vacuum evaporation, with a thickness of 8 nm, thereby preparing the narrow-band photodetector with wide-angle detection and imaging capability according to the present invention, the structure is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₂ Br ₁₁ /PTAA/Cr.

Example 5:

1. Select a hemispherical substrate with a diameter of 0.8cm (the material is ordinary glass, which can be obtained from commercial channels), ultrasonically clean it in ultrapure water, acetone and isopropanol for 15 minutes and then dry;

2. Evaporate metal Cr onto the surface of the hemispherical substrate as a cathode by vacuum evaporation, with a thickness of 13 nm, and then perform ultraviolet-ozone treatment on the surface of the metal Cr for 20 minutes, and then perform plasma treatment for 5 minutes;

3. Deposition of an electron transport layer on the surface of the cathode

(a) Dilute the purchased _SnO aqueous solution with ultrapure water to prepare an electron transport layer solution with a _SnO concentration of 0.1% wt;

(b) adding 600 μL of the electron transport layer solution obtained in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) Place the hemispherical substrate with the cathode prepared on the surface on a 65°C heating table, connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 2MPa, the spray rate is 0.12mL/min, and the electrons are transmitted The coating solution is sprayed onto the cathode surface; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, the rotation speed is 0.25r/min, and the translation speed is 15cm/s, so as to maintain the flatness of the sprayed film; during the spraying process, After each droplet of the solution completely covered the surface of the hemisphere, the entire surface of the hemisphere was purged with a high-speed nitrogen gas of 5 MPa to form a dry film; when the solution was exhausted, the film was annealed at 170 °C for 30 minutes, and then subjected to UV-ozone treatment 20 minutes, thereby obtaining an electron transport layer with a thickness of 10 nm on the surface of the cathode;

4. The PEA ₂ FA ₃ Pb ₄ I ₅ Br ₈ perovskite film is deposited on the surface of the electron transport layer, and the steps are as follows:

(a) Formamidine hydrohalide (FAI), lead halide (PbBr ₂ ), phenethylamine hydrohalide (PEAI) and methylamine hydrochloride (MACl) are in a ratio of 3:4: 2:1.2 is configured as a 0.5M (relative to lead ion) precursor solution, the solvent is a mixture of acetonitrile (ACN) and N,N-dimethylformamide (DMF), and the volume ratio is 2:3 to control the energy of the solution. Dissolve the perovskite powder completely;

(b) adding 1500 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2;

(c) place the hemispherical substrate with the electron transport layer deposited on the surface on a heating table at 100°C, connect the pneumatic spray gun in step (b) to an air compressor with an output pressure of 2MPa, and the spray rate is 0.15mL/min. The precursor solution is sprayed onto the surface of the electron transport layer; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, the rotation speed is 0.25r/min, and the translation speed is 10cm/s, so as to maintain the flatness of the sprayed film; During the process, after each droplet of the solution completely covers the surface of the hemisphere, the entire surface of the hemisphere is purged with a high-speed nitrogen gas of 5MPa to form a dry film;

(d) The hemispherical substrate sprayed with the wet perovskite film obtained in step (c) was annealed at 120°C for 10 minutes, then annealed at 140°C for 30 minutes, and finally annealed at 170°C for 60 minutes, maintaining during the annealing process In dark conditions, a perovskite film with a thickness of 12 μm was finally obtained;

5. The hole transport layer is deposited on the surface of the perovskite film, and the steps are as follows:

(a) The purchased poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) was prepared into a hole transport layer solution with a PTAA concentration of 0.1 mg/mL in toluene;

(b) adding 400 μL of the hole transport layer solution obtained in step (a) into a pneumatic spray gun with a model HD180 and a nozzle diameter of 0.2 mm;

(c) Fix the perovskite-coated hemispherical substrate on a heating table at 80 °C, and connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1.5 MPa, and the spraying time is determined by the total spraying volume. The spraying rate is 0.13mL/min, sprayed onto the hemispherical substrate, and a wet perovskite film is obtained on the outer surface of the hemisphere; during the spraying process, the rotation and translation of the hemispherical substrate are maintained, and the rotation speed is about 0.25r/min, The translation speed was 10 cm/s, the droplets of each solution completely covered the surface once, and the entire surface was blown with a high-speed nitrogen gas of 5 MPa to form a dry film on the surface; when the solution was exhausted, the hemisphere of the film was annealed at 100 °C for 10 minutes, the thickness of the obtained hole transport layer is 10 nm;

6. Evaporating metal Cr onto the surface of the hole transport layer as an anode by vacuum evaporation, with a thickness of 8 nm, thereby preparing the narrow-band photodetector with wide-angle detection and imaging capability according to the present invention, the structure is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₅ Br ₈ /PTAA/Cr.

Example 6

The prepared hemispherical substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr photodetector (Example 2) was connected to the anode and cathode of the current source meter, under different lighting conditions. The voltage-current density correlation was measured under the intensity of 820 nm monochromatic light. Figure 4(a) is the schematic diagram of the test system, and Figure 4(b) is the Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr photodetector under different illumination intensities, 820nm wavelength monochromatic Voltage-current density plot under light, the photodetector exhibits good self-voltage behavior and photoresponse behavior.

Example 7

The prepared hemispherical substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr photodetector (Example 2) was connected to the anode and cathode of the oscilloscope (MDO3000), and placed under certain illumination. Under the monochromatic light intensity, the signal trigger (Puyuan RIGOL DG1022Z) transmits a square wave signal to the monochromatic light, so that the monochromatic light output square wave signal passes through the oscilloscope, and the device receives the current signal image output by the square wave signal. Display, determine the responsiveness of the device to different light colors.

Fig. 5 is the normalized switching signal waveforms of the PEA ₂ FA ₃ Pb ₄ I ₁₃ perovskite hemispherical device at different wavelengths. It can be seen that there is a good switching signal at the response wavelength (820nm), and there is almost no signal at the non-response wavelength (532nm), indicating that the photodetector prepared by the present invention exhibits a good wavelength selective response.

Example 8

1. The flat substrate (the material is ordinary glass, the length, width, and height dimensions are 1.5×1.5×0.2cm), ultrasonically cleaned in ultrapure water, acetone, and isopropanol for 15 minutes each, and dried in an oven;

2. Evaporate metal Cr onto the surface of the hemispherical substrate as an anode by vacuum evaporation, with a thickness of 12 nm, and then perform ultraviolet-ozone treatment on the surface of metal Cr for 20 minutes, and then perform plasma treatment for 5 minutes;

3. Deposit a hole transport layer on the surface of the anode

(a) Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) aqueous solution was diluted with ultrapure water to obtain hole transport with a PEDOT:PSS concentration of 0.1%wt layer solution;

(b) adding 600 μL of the hole transport layer solution in step (a) into a pneumatic spray gun with model HD180 and a nozzle diameter of 0.2 mm;

(c) Place the flat substrate with the anode prepared on the surface on a heating table at 60°C, connect the pneumatic spray gun in step (b) to an air compressor, the output pressure is 1.5MPa, the spray rate is 0.15mL/min, and the air is The hole transport layer solution is sprayed onto the surface of the anode. During the spraying process, the translation of the plane substrate is maintained, and the translation speed is 10 cm/s, so as to maintain the flatness of the sprayed film; during the spraying process, the droplets of each solution are completely covered. After the hemispherical surface, the entire planar substrate surface was purged with 5MPa high-speed nitrogen gas to form a relatively dry film; after the solution was consumed, the film was annealed at 170 °C for 30 minutes, thereby obtaining a hole transport layer with a thickness of 10 nm on the anode surface;

(4) Deposition of PEA ₂ FA ₃ Pb ₄ I ₁₃ perovskite film on the surface of the hole transport layer

(a) Formamidine hydrohalide (FAI), lead halide (PbI ₂ ), phenethylamine hydrohalide (PEAI) and methylamine hydrochloride (MACl) were prepared in a 3:4:2:1.6 configuration Precursor solution with lead ion concentration of 0.6M, the solvent is a mixed solvent of acetonitrile (ACN) and N,N-dimethylformamide (DMF), or ethylene glycol methyl ether (2-Me) and N,N- The mixed solvent of dimethylformamide (DMF), the volume ratio of acetonitrile (ACN) and N,N-dimethylformamide (DMF) is 1:1;

(b) adding 1500 μL of the precursor solution prepared in step (a) into a pneumatic spray gun with a nozzle model HD180 and a diameter of 0.2 mm;

(c) The hemispherical substrate with the hole transport layer deposited on the surface is placed on a heating table at 100°C, the pneumatic spray gun in step (b) is connected to an air compressor with an output pressure of 1.5MPa, and the spray rate is 0.15mL/min , spray the precursor solution on the surface of the hole transport layer; during the spraying process, keep the rotation and translation of the planar substrate, the rotation speed is 0.25r/min, and the translation speed is 10cm/s, so as to maintain the flatness of the sprayed film; In the process of spraying, after each droplet of the solution completely covers the surface of the substrate, the entire surface of the hemisphere is purged with a high-speed nitrogen gas of 5MPa to form a relatively dry film;

(d) The hemispherical substrate obtained in step (c) was annealed at 120°C for 10 minutes, then annealed at 160°C for 30 minutes, and finally annealed at 170°C for 60 minutes, maintaining a dark condition during the annealing process, thereby obtaining a thickness of 10 μm. perovskite thin films;

(5) Evaporating the purchased fullerene (C ₆₀ ) onto the surface of the perovskite thin film by vacuum evaporation to obtain an electron transport layer with a thickness of 15 nm;

(6) The purchased 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) was evaporated to the surface of the electron transport layer by vacuum evaporation to obtain a buffer with a thickness of 6 nm Floor;

(7) The metal Cr was evaporated to the surface of the buffer layer as a cathode by vacuum evaporation with a thickness of 10 nm; thus a planar substrate/Cr/PEDOT:PSS/PEA ₂ FA ₃ PbI ₁₃ /C ₆₀ /BCP/Cr photodetector was prepared.

The PEA ₂ FA ₃ Pb ₄ I ₁₃ perovskite hemispherical device prepared in Example 2 and the planar device prepared in this example are respectively connected to wires. Taking the distance from the light source to the center of the device as the radius and the center of the device as the dot, change the position of the light source along the semicircle, and measure and record the electrical signal at each position by the current source meter (defining the angle of incident light when the light source illuminates the device vertically is 0 degrees; when the light source illuminates the device horizontally, the incident light angle is 90 degrees).

Figure 6(a) is a schematic diagram of the angle response test system, and Figure 6(b) is the response range curve of the plane detector and the hemispherical detector to the incident angle of monochromatic light; it can be seen that the hemispherical photodetector responds to the incident light of different angles Both have good responsiveness. Hemispherical devices show extremely high wide-angle detection capabilities. Under point light sources at various angles, the responsiveness is almost unchanged, and the corresponding angle can reach (-90 degrees to +90 degrees); while flat devices The responsiveness is heavily dependent on the incident light angle.

Example 9

The four hemispherical photodetectors with changing the ratio of halogen X (X=I, Br) were tested for the light response capability of different wavelengths, and finally obtained by adjusting the halogen ratio of the interlayer perovskite to control the device's selection of different light colors corresponding photodetectors.

The corresponding relationship between the device structure and the central response wavelength is as follows:

Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr(820nm),

Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₅ Br ₈ /PTAA/Cr(660nm),

Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₂ Br ₁₁ /PTAA/Cr(600nm),

Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₃ /PTAA/Cr(550nm),

FIG. 7( a ) is a schematic diagram of a testing system for testing the light responsiveness of a device to different wavelengths. It is measured by external quantum efficiency (EQE); in the figure, the xenon light source passes through a monochromator and a chopper, and outputs monochromatic light with a certain frequency to the detector. The current signal generated by the detector is amplified by the preamplifier and converted into a voltage signal. The lock-in amplifier amplifies the same-frequency signal again, and input it into the computer to calculate the current density generated by the detector and the photon density irradiated on the detector. to calculate the quantum efficiency. The responsiveness of each wavelength of the device is measured by the quantum efficiency (EQE) of different wavelengths.

Figure 7(b) corresponds to the EQE diagrams of the above four device structures respectively, the abscissa is the wavelength, and the ordinate is the normalized EQE. Its full width at half maximum is ~20 nm. The figure illustrates that each device can only respond specifically to optical signals at wavelengths near its corresponding central wavelength, and has almost no response to other wavelengths. It shows that the device exhibits the ability of narrow-band light color recognition. The device only responds to a specific color of light, and we control the ratio of X species I and Br in the host perovskite material to controllably adjust the wavelength position of this specific recognition of the device.

Example 10

Construction of imaging system of narrow-band photodetector for wide-angle detection:

(a) Fix the 820nm monochromatic LED light source on the X-Y two-dimensional displacement platform, and the light source power is 3W.

(b) Connect the two-dimensional displacement platform described in (a) to a computer to control its movement, and the moving unit distance is 500 μm/step;

(c) Connect the LED light source described in (a) to a function generator (Puyuan RIGOL DG1022Z), and output a square wave signal with a frequency of 70Hz to light up the LED light source, and at the same time connect the signal to a lock-in amplifier (SR830) Combined use, the electrical signal converted by the device and the electrical signal generated by the function generator are used as the same frequency reference, as shown in Figure 8;

(d) The object to be measured is placed on the glass platform under the light source, and the hemispherical light detector is placed under the glass platform;

(e) Adjust the angle of the hemispherical photodetector described in step (d), as shown in FIG. 9 . Hemispherical photodetectors can image objects at extreme angles relative to planar photodetectors. The angle of the object relative to the detector can be adjusted by changing the relative angle between the plane where the hemispherical light detector base is located, the light source and the object. Here we select objects occupying the imaging range of the detector from -8 degrees to +30 degrees and the imaging range of -52 degrees to -90 degrees, respectively, as shown in Figure 10. The photodetector is connected to the preamplifier (SR570), the lock-in amplifier (SR830) and the computer;

(f) Using a computer to read data from the system to obtain imaging results. The imaging device type is: Cr/PEDOT:PSS/PEA ₂ FA ₃ Pb ₄ I ₁₃ /C ₆₀ /BCP/Cr.

FIG. 9 is a schematic diagram of an angle occupied by an object, wherein θ ₁ and θ ₂ are used to calculate the incident angle of the object. Figure 10. The angled objects used for imaging occupy angles of -52 to -90 degrees and -8 to +30 degrees. The imaging of these two angular ranges is also applied to the planar light detector. The imaging results are shown in Fig. 11. Figure 11(a) The plane photodetector imaging, the angle occupied by the object is from -8 degrees to +30 degrees; Figure 11(b) The plane photodetector imaging, the angle occupied by the object is from -90 degrees to -52 degrees; Figure 11 (c) Hemispherical photodetector imaging, the angle occupied by the object is from -8 degrees to +30 degrees; Fig. 11(d) The hemispherical photodetector imaging, the angle occupied by the object is from -90 degrees to -52 degrees. Figure 11 illustrates that the imaging range of the hemispherical device is much larger than that of the planar detector, showing the capability of wide-angle detection. Especially for the grazing angle imaging (-90 degrees), the plane imaging is obviously limited, while the hemispherical detector can still maintain the imaging effect.

Example 11

Construction of the imaging system of the narrow-band photodetector for wide-angle detection:

(a) Fix a 550nm monochromatic LED light source on the X-Y two-dimensional displacement platform, and the light source power is 3W.

(b) Connect the two-dimensional displacement platform described in (a) to a computer to control its movement, and the moving unit distance is 500 μm/step;

(c) Connect the LED light source described in (a) to a function generator (Puyuan RIGOL DG1022Z), and output a square wave signal with a frequency of 70Hz to light up the LED light source, and at the same time connect the signal to a lock-in amplifier (SR830) Combined use, the electrical signal converted by the device and the electrical signal generated by the function generator are used as a reference;

(d) The object to be measured is placed on the glass platform under the light source, and the hemispherical light detector is placed under the glass platform;

(e) Adjust the angle of the hemispherical light detector described in step (d), and adjust the angle of the hemispherical detector to be collinear with the light source object at an angle of 0 degrees. The photodetector is connected to the preamplifier (SR570), the lock-in amplifier (SR830) and the computer.

The hemispherical photodetector of the device structure Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₃ /PTAA/Cr was placed under a glass platform and imaged using an imaging system.

Example 12

Construction of the imaging system of the narrow-band photodetector for wide-angle detection:

(a) Fix a 600nm monochromatic LED light source on the X-Y two-dimensional displacement platform, and the light source power is 3W.

(b) Connect the two-dimensional displacement platform described in (a) to a computer to control its movement, and the moving unit distance is 500 μm/step;

(c) Connect the LED light source described in (a) to a function generator (Puyuan RIGOL DG1022Z), and output a square wave signal with a frequency of 70Hz to light up the LED light source, and at the same time connect the signal to a lock-in amplifier (SR830) Combined use, the electrical signal converted by the device and the electrical signal generated by the function generator are used as a reference;

(d) The object to be measured is placed on the glass platform under the light source, and the hemispherical light detector is placed under the glass platform;

(e) Adjust the angle of the hemispherical light detector described in step (d), and adjust the angle of the hemispherical detector to be collinear with the light source object at an angle of 0 degrees. The photodetector is connected to the preamplifier (SR570), the lock-in amplifier (SR830) and the computer.

The hemispherical photodetector of the device structure Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₂ Br ₁₁ /PTAA/Cr was placed under a glass platform and imaged using an imaging system.

Example 13

Construction of the imaging system of the narrow-band photodetector for wide-angle detection:

(a) Fix a 660nm monochromatic LED light source on the X-Y two-dimensional displacement platform, and the light source power is 3W.

(b) Connect the two-dimensional displacement platform described in (a) to a computer to control its movement, and the moving unit distance is 500 μm/step;

(c) Connect the LED light source described in (a) to a function generator (Puyuan RIGOL DG1022Z), and output a square wave signal with a frequency of 70Hz to light up the LED light source, and at the same time connect the signal to a lock-in amplifier (SR830) Combined use, the electrical signal converted by the device and the electrical signal generated by the function generator are used as a reference;

(d) The object to be measured is placed on the glass platform under the light source, and the hemispherical light detector is placed under the glass platform;

(e) Adjust the angle of the hemispherical light detector described in step (d), and adjust the angle of the hemispherical detector to be collinear with the light source object at an angle of 0 degrees. The photodetector is connected to the preamplifier (SR570), the lock-in amplifier (SR830) and the computer.

The hemispherical photodetector of the device structure Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₅ Br ₈ /PTAA/Cr was placed under a glass platform and imaged using an imaging system.

Figure 12 shows the imaging of the prepared narrow-band photodetectors with different response wavelengths prepared by adjusting the halogen response imaging under the monochromatic light corresponding to its center. The corresponding response wavelengths are 550nm, 600nm, 660nm, and the summation diagram obtained by superimposing light colors. Such imaging will greatly reduce the influence of light from other colors on the imaging. Since the device can only image light in a certain range of colors around its central wavelength, it has almost no responsiveness to light in other wavelengths. Therefore, only the light source of the corresponding light color can meet the imaging requirements of the device, and the light source of other light colors cannot make the device image in response. This imaging method selectively filters out the interference of other colors of light on the imaging process, and at the same time, it is possible to select a certain color of light for imaging purposes.

Fig. 12(a) The structure of the 550nm monochromatic light imaging device is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ Br ₁₃ /PTAA/Cr; Fig. 12(b) The structure of the 600 nm monochromatic light imaging device is hemispherical substrate/ Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₂ Br ₁₁ /PTAA/Cr; Figure 12(c) The structure of the 660nm monochromatic light imaging device is hemispherical substrate/Cr/SnO ₂ /PEA ₂ FA ₃ Pb ₄ I ₅ Br ₈ /PTAA/Cr; Fig. 12(d) The superimposed image of different monochromatic light imaging results, this imaging can represent the object more realistically, and each monochromatic image can provide great help for post-image processing. This imaging result facilitates the analysis of object images in terms of light color wavelengths.

In conclusion, the light detector proposed by the present invention has broad application prospects in wide-angle and narrow-band detection.

Claims (4)

1. A preparation method of a narrow-band photodetector with wide-angle detection imaging capability sequentially comprises a hemispherical substrate, an anode, a hole transport layer, a perovskite thin film, an electron transport layer, a buffer layer and a cathode, and comprises the following steps:

(1) selecting a hemispherical substrate with the diameter of 0.8-2 cm, carrying out ultrasonic cleaning in ultrapure water, acetone and isopropanol for 10-20 minutes respectively, and then drying;

(2) evaporating metal Cr to the surface of a hemispherical substrate through vacuum evaporation to be used as an anode, wherein the thickness of the metal Cr is 8-15 nm, then carrying out ultraviolet-ozone treatment on the surface of the metal Cr for 15-30 minutes, and then carrying out plasma treatment for 5-10 minutes;

(3) depositing a hole transport layer on the surface of the anode

(a) Diluting a poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid) water solution with ultrapure water to obtain a hole transport layer solution with the concentration of 0.05-0.2 wt% of poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid);

(b) adding 400-1000 mu L of the hole transport layer solution in the step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) placing the hemispherical substrate with the anode prepared on the surface on a hot table at the temperature of 60-80 ℃, connecting the pneumatic spray gun in the step (b) with an air compressor, wherein the output pressure is 1-3 MPa, the spraying speed is 0.10-0.3 mL/min, spraying the hole transport layer solution on the surface of the anode, and in the spraying process, keeping the rotation and translation of the hemispherical substrate, the rotation speed is 0.20-0.30 r/min, and the translation speed is 5-20 cm/s, so that the flatness of the sprayed film is kept; in the spraying process, after the liquid drops of the solution completely cover the surface of the hemisphere every time, blowing the whole hemisphere surface by high-speed nitrogen with the pressure of 4-7 MPa until a dry film is formed; when the solution is exhausted, annealing the film for 20-40 minutes at 160-180 ℃, thereby obtaining a hole transport layer with the thickness of 10-100 nm on the surface of the anode;

(4) depositing PEA on the surface of the hole transport layer₂FA₃Pb₄X₁₃Perovskite film, X ═ Br, I or Br and I, with the sum of subscripts 13

(a) Mixing formamidine hydrohalide, lead halide, phenethylamine hydrohalide and methylamine hydrochloride according to PEA₂FA₃Pb₄X₁₃Of (a)The lead ion concentration of the precursor solution is 0.4-0.6M, the solvent is a mixed solvent of acetonitrile and N, N-dimethylformamide or a mixed solvent of ethylene glycol monomethyl ether and N, N-dimethylformamide, and the volume ratio of the acetonitrile or the ethylene glycol monomethyl ether to the N, N-dimethylformamide is 1: 1-3;

(b) adding 500-2000 mu L of the precursor solution prepared in the step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) placing the hemispherical substrate with the hole transport layer deposited on the surface on a heating table at the temperature of 80-120 ℃, connecting the pneumatic spray gun in the step (b) with an air compressor with the output pressure of 1-3 MPa, spraying at the speed of 0.1-0.3 mL/min, and spraying the precursor solution on the surface of the hole transport layer; in the spraying process, the rotation and translation of the hemispherical substrate are kept, the rotation speed is 0.20-0.30 r/min, and the translation speed is 5-20 cm/s, so that the flatness of the sprayed film is kept; in the spraying process, after the liquid drops of the solution completely cover the surface of the hemisphere each time, blowing the whole hemisphere surface by using high-speed nitrogen with the pressure of 4-7 MPa until a dry film is formed;

(d) annealing the hemispherical substrate obtained in the step (c) at 80-120 ℃ for 8-15 minutes, then annealing at 120-140 ℃ for 20-40 minutes, finally annealing at 160-170 ℃ for 60-90 minutes, and keeping a dark condition in the annealing process, thereby obtaining a perovskite thin film with the thickness of 2-40 mu m;

(5) the obtained fullerene (C) was evaporated in vacuo₆₀) Evaporating the film on the surface of the perovskite film to obtain an electron transmission layer with the thickness of 15-30 nm;

(6) evaporating the purchased 2, 9-dimethyl-4, 7-biphenyl-1, 10-phenanthroline to the surface of the electron transport layer through vacuum evaporation to obtain a buffer layer with the thickness of 4-10 nm;

(7) evaporating metal Cr to the surface of the buffer layer through vacuum evaporation to be used as a cathode, wherein the thickness of the buffer layer is 8-15 nm; the prepared structure with wide-angle detection imaging capability is a hemispherical substrate/Cr/PEDOT: PSS/PEA₂FA₃Pb₄X₁₃/C₆₀a/BCP/Cr narrow-band photodetector.

2. A preparation method of a narrow-band photodetector with wide-angle detection imaging capability comprises the following steps:

(1) selecting a hemispherical substrate with the diameter of 0.8-2 cm, carrying out ultrasonic cleaning in ultrapure water, acetone and isopropanol for 10-20 minutes respectively, and then drying;

(2) evaporating metal Cr to the surface of a hemispherical substrate through vacuum evaporation to be used as a cathode, wherein the thickness of the cathode is 8-15 nm, then carrying out ultraviolet-ozone treatment on the surface of the metal Cr for 15-30 minutes, and then carrying out plasma treatment for 5-10 minutes;

(3) depositing an electron transport layer on the surface of the cathode

(a) SnO to be purchased₂The aqueous solution is diluted with ultrapure water to prepare SnO₂An electron transport layer solution having a concentration of 0.05 to 0.1 wt%;

(b) adding 400-1000 mu L of the electron transport layer solution obtained in the step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) placing the hemispherical substrate with the cathode prepared on the surface on a heating table at 60-80 ℃, connecting the pneumatic spray gun in the step (b) with an air compressor, spraying the electron transport layer solution on the surface of the cathode, wherein the output pressure is 1-3 MPa, and the spraying speed is 0.10-0.20 mL/min; in the spraying process, the rotation and translation of the hemispherical substrate are kept, the rotation speed is 0.20-0.30 r/min, and the translation speed is 5-20 cm/s, so that the flatness of the sprayed film is kept; in the spraying process, after the liquid drops of the solution completely cover the surface of the hemisphere each time, blowing the whole hemisphere surface by using high-speed nitrogen with the pressure of 4-7 MPa until a dry film is formed; after the solution is exhausted, annealing the film for 20-40 minutes at 160-180 ℃, and then carrying out ultraviolet-ozone treatment for 15-30 minutes, thereby obtaining an electron transport layer with the thickness of 10-100 nm on the surface of the cathode;

(4) depositing PEA on the surface of the electron transport layer₂FA₃Pb₄X₁₃Perovskite film, X ═ Br, I or Br and I, with the sum of subscripts 13

(a) Mixing formamidine hydrohalide, lead halide, phenethylamine hydrohalide and methylamine saltAcid salt according to PEA₂FA₃Pb₄X₁₃The lead ion concentration of the precursor solution is 0.4-0.6M, the solvent is a mixed solvent of acetonitrile and N, N-dimethylformamide or a mixed solvent of ethylene glycol monomethyl ether and N, N-dimethylformamide, and the volume ratio of the acetonitrile or the ethylene glycol monomethyl ether to the N, N-dimethylformamide is 1: 1-3;

(b) adding 500-2000 mu L of the precursor solution prepared in the step (a) into a pneumatic spray gun with a nozzle diameter of 0.2-0.5 mm;

(c) placing the hemispherical substrate with the electron transport layer deposited on the surface on a heating table at the temperature of 80-120 ℃, connecting the pneumatic spray gun in the step (b) with an air compressor with the output pressure of 1-3 MPa, spraying at the speed of 0.1-0.3 mL/min, and spraying the precursor solution on the surface of the electron transport layer; in the spraying process, the rotation and translation of the hemispherical substrate are kept, the rotation speed is 0.20-0.30 r/min, and the translation speed is 5-20 cm/s, so that the flatness of the sprayed film is kept; in the spraying process, after the liquid drops of the solution completely cover the surface of the hemisphere each time, blowing the whole hemisphere surface by using high-speed nitrogen with the pressure of 4-7 MPa until a dry film is formed;

(d) annealing the hemispherical substrate obtained in the step (c) at 80-120 ℃ for 8-15 minutes, then annealing at 120-140 ℃ for 20-40 minutes, finally annealing at 160-170 ℃ for 60-90 minutes, and keeping a dark condition in the annealing process; thereby obtaining a perovskite thin film with the thickness of 2-40 mu m;

(5) depositing a hole transport layer on the surface of the perovskite thin film, wherein the steps are as follows:

(a) preparing poly [ bis (4-phenyl) (2,4, 6-trimethylphenyl) amine ] and toluene into a hole transport layer solution with the concentration of the poly [ bis (4-phenyl) (2,4, 6-trimethylphenyl) amine ] of 0.05-0.2 mg/mL;

(b) adding 400-1000 mu L of the hole transport layer solution obtained in the step (a) into a pneumatic spray gun with a nozzle with the diameter of 0.2-0.5 mm;

(c) fixing a hemispherical substrate with a perovskite film prepared on the surface on a heating table at 60-80 ℃, connecting a pneumatic spray gun in the step (b) with an air compressor, wherein the output pressure is 1-3 MPa, the spraying speed is 0.10-0.20 mL/min, spraying the hole transport layer solution on the perovskite film, and in the spraying process, keeping the rotation and translation of the hemispherical substrate, the rotation speed is 0.20-0.30 r/min, and the translation speed is 5-20 cm/s, so that the flatness of the sprayed film is kept; in the spraying process, after the liquid drops of the solution completely cover the surface of the hemisphere every time, blowing the whole hemisphere surface by high-speed nitrogen with the pressure of 4-7 MPa until a relatively dry film is formed; when the solution is exhausted, annealing the film at 90-110 ℃ for 5-15 minutes to obtain a hole transport layer with the thickness of 10-100 nm;

(6) evaporating metal Cr to the surface of the hole transport layer through vacuum evaporation to be used as an anode, wherein the thickness of the metal Cr is 8-15 nm, and thus the prepared metal Cr/SnO with a hemispherical substrate/SnO₂/PEA₂FA₃Pb₄X₁₃a/PTAA/Cr narrow band photodetector.

3. A narrow-band photodetector with wide-angle detection imaging capability, comprising: prepared by the process of claim 1 or 2.

4. An imaging method of a narrow-band photodetector with wide-angle detection imaging capability comprises the following steps:

(a) fixing a monochromatic light LED light source with adjustable central wavelength of 400-900 nm on an X-Y two-dimensional displacement platform, wherein the power of the light source is 3-10W;

(b) connecting the X-Y two-dimensional displacement platform in the step (a) to a computer, and controlling the movement of the X-Y two-dimensional displacement platform, wherein the unit distance of the movement is 200-500 mu m/step;

(c) connecting the LED light source in the step (a) with a function generator, wherein the function generator outputs a square wave signal with the frequency of 20-90 Hz;

(d) placing an object to be tested on a glass platform below an LED light source, and placing the hemispherical narrow-band photodetector of claim 3 below the glass platform;

(e) adjusting the angle of the hemispherical narrow-band photodetector in the step (d) to form a certain included angle with an imaging system, and then connecting the hemispherical narrow-band photodetector with a preamplifier, a phase-locked amplifier and a computer; in the experiment, the function generator outputs square wave signals to the light source and has the same frequency with the phase-locked amplifier, the device receives light signals and converts the light signals into current signals to be output to the preamplifier, the preamplifier converts the current signals into voltage signals, the voltage signals are amplified and transmitted to the phase-locked amplifier, and the phase-locked amplifier further amplifies voltage information of the signals with the same frequency from the preamplifier and the function generator and transmits the voltage information to the computer. Reading a data point when the stepping motor moves one step to form a data matrix;

(f) and reading the voltage data matrix by using a computer, and finally obtaining an imaging result by using MATLAB software.

Images