A photoelectrical response device, a preparation method and use
By combining a vertical heterojunction array structure with an organic photoresponse layer, the problems of dark current and water-oxygen erosion in black phosphorus photodetectors were solved, realizing a photodetector with high signal-to-noise ratio and wide spectral response, thus improving the detection sensitivity and lifespan of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JISHI CORE MATERIAL (HANGZHOU) TECHNOLOGY CO LTD
- Filing Date
- 2026-03-17
- Publication Date
- 2026-06-16
AI Technical Summary
Existing black phosphorus photodetectors have high dark current and high carrier mobility at room temperature, resulting in large dark current and susceptibility to water and oxygen corrosion, which limits their application in wide-spectral response and long-term operation.
A vertical heterojunction array structure is adopted, using a combination of black phosphorus film layer and organic photoelectric response layer. The organic photoelectric response layer is used as an isolation layer to block water and oxygen erosion, and tetracoordinated boride organic light-emitting material is selected as organic photoelectric response layer to enhance light absorption and reduce dark current.
It effectively suppresses dark current, improves signal-to-noise ratio and detection sensitivity, achieves wide spectrum response, enhances carrier mobility, and extends device lifetime.
Smart Images
Figure CN122227768A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optoelectronic semiconductor devices, specifically to a photoelectric response device, its preparation method, and its application. Background Technology
[0002] Photodetectors are key electronic devices that convert light signals into electrical signals, and they are widely used in many fields such as optical communication, image sensing, environmental monitoring, military reconnaissance, biomedical imaging, and autonomous driving. Traditional silicon-based devices and indium gallium arsenide photodetectors are limited by their band gaps and can only operate in the visible to near-infrared band. High-performance mid-infrared detectors (such as mercury cadmium telluride, HgCdTe) require low-temperature (77K) cooling, are expensive, and are difficult to integrate with other circuits. Therefore, the development of photodetectors that combine wide spectral response, room temperature operation, and easy integration is urgently needed.
[0003] Two-dimensional materials possess unique advantages such as the absence of dangling bonds on the surface, weak van der Waals interactions between layers, and tunable band gaps. Two-dimensional materials, represented by graphene and transition metal dichalcogenides (TMDs), exhibit unique electrical and optical properties. However, graphene's zero band gap characteristic limits its photoresponsivity, while the band gaps of TMDs are mostly confined to the visible light band and are difficult to tune. Neither can effectively cover key application bands such as near-infrared (IR) and mid-infrared (MIR). Black phosphorus (BP), on the other hand, possesses a directly tunable band gap (0.3-2.0 eV) and high carrier mobility (1000 cm⁻¹). 2 ·V -1 ·s -1 Two-dimensional semiconductor materials with strong optical anisotropy exhibit irreplaceable advantages in broadband detection and polarization-sensitive photodetectors. However, the application of black phosphorus still faces two major bottlenecks: ① Black phosphorus has a high room-temperature carrier concentration and high room-temperature carrier mobility, which amplifies dark current, resulting in large device dark current; ② The surface is susceptible to "erosion" by water and oxygen in the air, leading to high-density defect states, which triggers large dark current and nonradiative recombination, limiting the device's sensitivity, responsivity, and long-term application, thus restricting its application in fast-response photodetectors.
[0004] Therefore, there is a need in this field to develop a BP-based optoelectronic device that can effectively suppress dark current to improve signal-to-noise ratio and detection sensitivity, while also constructing a stable isolation layer to block water and oxygen erosion, without reducing the carrier mobility of the device. Summary of the Invention
[0005] To address the shortcomings of existing technologies, one objective of this invention is to provide a photoelectric response device, comprising a transparent electrode layer, and a black phosphorus film layer, an organic photoelectric response layer, and a photocurrent extraction electrode layer sequentially disposed on one side of the transparent electrode layer;
[0006] The organic photoelectric response layer has an absorption spectrum in the range of at least 300~600nm (e.g., 320nm, 350nm, 370nm, 420nm, 460nm, 480nm, 530nm, 580nm, etc.) and an emission spectrum bandwidth ≤60nm (e.g., 58nm, 55nm, 52nm, 48nm, 45nm, 40nm, 38nm, 34nm, 30nm, 28nm, 25nm, etc.).
[0007] The photoelectric response device provided in this application is a vertical heterojunction array device. During use, the photocurrent extraction electrode layer and the transparent electrode layer of the photoelectric response device are respectively connected to the conductive circuit to form a loop. Compared with traditional field-effect transistor (FET) type photodetectors, the photogenerated carriers in this application do not need to migrate from the source to the drain along the lateral channel (usually at the micrometer scale). Instead, the electrodes are constructed on the upper and lower surfaces of the thin film, making the carrier transport direction perpendicular to the thin film plane. The transport path is shortened to the nanometer scale, and out-of-plane incident light increases the effective photosensitive area of the material. In the vertical array device, this application sets an organic photoelectric response layer on the surface of the black phosphorus film layer (away from the ITO side). On the one hand, it acts as an isolation layer to block water and oxygen erosion; on the other hand, it increases the resistance, which can effectively suppress dark current to improve the signal-to-noise ratio and detection sensitivity.
[0008] Furthermore, in the photoelectric response device provided in this application, the organic photoelectric response layer has a wide absorption spectrum and a narrow emission bandwidth. That is to say, this application selects an organic photoelectric response material with a wide absorption and narrow emission as the isolation layer of the black phosphorus film to block water and oxygen and reduce dark current. On the one hand, this can achieve the function of blocking water and oxygen and reducing dark current. On the other hand, it can also improve the absorption of photoelectrons, increase the number of photogenerated carriers, make up for the reduction of photocurrent caused by setting the organic photoelectric response layer, and even synergistically improve the mobility of carriers.
[0009] Preferably, the organic photoresponse layer has an emission spectrum with a bandwidth of less than 60 nm between 550 and 750 nm. The emission spectrum of the organic photoresponse layer in the near-infrared (550-750 nm) range helps to reduce the dark current of the device in the near-infrared range.
[0010] Preferably, the organic photoelectric response layer material is a four-coordinate boride organic light-emitting material, preferably an N,C-chelate four-coordinate boron complex, and more preferably any one or a combination of at least two boron-nitrogen four-coordinate boron complexes having a D-π-A structure; wherein D is a donor group, including any one or a combination of at least two substituted or unsubstituted carbazole groups and substituted or unsubstituted indole groups; and wherein A is an acceptor group, including any one or a combination of at least two substituted or unsubstituted pyridinyl groups.
[0011] Tetracoordinate boride organic light-emitting materials (especially N,C-chelated tetracoordinate boron complexes) possess inherent electronic vacancy characteristics, excellent thermo / photochemical stability, high fluorescence quantum efficiency, and precisely tunable photoelectric properties. Using them as organic light-emitting materials can synergistically enhance photoelectric conversion efficiency and improve carrier mobility. Furthermore, boron-nitrogen tetracoordinate boron complexes with a D-π-A structure have π-conjugated systems in both the D and A groups, thus extending the π-conjugated system and providing a push-pull electronic structure. This allows for effective tuning of the emission wavelength of the organic light-emitting material to the near-infrared region.
[0012] Preferably, the organic photoelectric response material comprises one or a combination of at least two of the following materials:
[0013] (Recorded as BN1) (Referred to as BN2) (Recorded as BN3) (Referred to as BN4).
[0014] The four organic photoelectric response materials can achieve both high luminous efficiency and narrow-band emission spectrum in the near-infrared band, especially with an emission spectrum with a bandwidth of less than 60 nm in the 550~750 nm range.
[0015] This application does not specifically limit the type of transparent electrode; any conductive electrode that can transmit light can be used in this application. Preferably, the transparent electrode includes any one of ITO transparent electrode, graphene transparent electrode, FTO transparent electrode, and ZnO transparent electrode.
[0016] Preferably, the black phosphorus film is formed by the self-assembly of black phosphorus nanosheets at the gas-liquid interface.
[0017] This application does not specify a particular method for preparing black phosphorus nanosheets; typically, but not limitingly, black phosphorus nanosheets prepared by electrochemical exfoliation are used. The black phosphorus nanosheets described in this application refer to black phosphorus sheet layers with a thickness ≤ 2~5 nm and a two-dimensional planar dimension ≥ 10 μm.
[0018] The gas-liquid interface self-assembly utilizes the large specific surface area of black phosphorus nanosheets and the large surface tension of water to allow the black phosphorus nanosheets to float on the surface of ultrapure water, thereby achieving the self-assembly of the black phosphorus nanosheets.
[0019] Preferably, the ratio of the thickness of the black phosphorus film layer to the thickness of the organic photoelectric response layer is 0.75~15, for example, 1, 2, 5, 8, 10, 13, etc., preferably 1~15.
[0020] The appropriate ratio of the thickness of the black phosphorus film to the thickness of the organic photoresponse layer can ensure that the black phosphorus film generates a sufficient number of photogenerated carriers. On the other hand, the appropriate thickness of the organic photoresponse layer can reduce the dark current generated during the migration of photogenerated carriers, thereby achieving better carrier mobility and lower dark current, and further improving the photoelectric conversion efficiency of the device.
[0021] Preferably, the thickness of the black phosphorus film layer is 15nm~30nm, such as 17nm, 20nm, 23nm, 27nm, etc.
[0022] Preferably, the thickness of the organic photoelectric response layer is 2nm~20nm, such as 5nm, 8nm, 10nm, 12nm, 15nm, etc.
[0023] Preferably, the photocurrent extraction electrode layer includes any one of a Cr / Au layer, an Ag layer, and a tungsten metal layer.
[0024] This application does not specifically limit the material and structure of the photocurrent extraction electrode; any electrode structure capable of extracting photocurrent can be used in this application. The Cr / Au layer refers to a photocurrent extraction electrode layer consisting of two layers: a Cr layer and an Au layer. The Cr layer is in contact with the organic photoresponse layer, and the Au layer is disposed on the side of the Cr layer away from the organic photoresponse layer. The thickness of the Au layer can, for example, be 4-7 nm for the Cr layer and 50-100 nm for the Au layer. The thickness of the Ag layer and tungsten metal layer is also independently selected from 50 nm to 100 nm.
[0025] Preferably, the photocurrent-deriving electrode layer has a patterned structure, and more preferably a patterned structure of a block array.
[0026] The second objective of this application is to provide a method for fabricating a photoelectric response device as described in the first objective, comprising the following steps:
[0027] (1) Electrochemically exfoliate the bulk black phosphorus in the dispersant to obtain black phosphorus nanosheets and obtain a black phosphorus nanosheet dispersion. Add the black phosphorus nanosheet dispersion to pure water, and the black phosphorus nanosheets perform gas-liquid interface self-assembly on the surface of pure water to form a black phosphorus film.
[0028] (2) After placing the transparent electrode sheet below the gas-liquid interface, pull it up to transfer the black phosphorus film to the surface of the transparent electrode sheet. After drying, anneal to obtain the structure of black phosphorus film layer / transparent electrode layer.
[0029] (3) Spin-coating an organic photoelectric response material dispersion onto the surface of the black phosphorus film layer in the structure of black phosphorus film layer / transparent electrode layer, drying, and annealing to obtain the structure of organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer;
[0030] (4) A photocurrent extraction electrode layer is formed on the surface of an organic photoelectric response material with an organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure to obtain the photoelectric response device.
[0031] In the preparation method of this application, the electrochemical exfoliation of bulk black phosphorus to prepare black phosphorus nanosheets can quickly and efficiently obtain black phosphorus nanosheets. The method of gas-liquid self-assembly into black phosphorus film is simple and easy to operate. The black phosphorus film is transferred to the surface of transparent electrode sheet by the lifting method, and the thickness of the black phosphorus film layer can be easily controlled by the number of lifting times, so as to achieve controllable preparation of black phosphorus film layer thickness.
[0032] Preferably, the photocurrent-deriving electrode layer has a patterned structure, and more preferably a patterned structure of a block array.
[0033] The blocky structure of the patterned array means that the photocurrent-deriving electrode layer is divided into small blocks attached to the surface of the organic photoresponse material.
[0034] Preferably, the dispersant in step (1) includes any one or a combination of at least two of N,N-dimethylformamide, propylene carbonate, dimethyl sulfoxide, and N-methylpyrrolidone.
[0035] Preferably, the bulk black phosphorus is black phosphorus crystal with a purity ≥99.999%.
[0036] Preferably, the electrochemical stripping solution is a tetrabutylammonium acetate solution, and more preferably a tetrabutylammonium acetate solution with a concentration of 0.001~0.003 mol / L.
[0037] Preferably, the volume of the electrochemical stripping solution is 10 mL to 20 mL.
[0038] Preferably, the electrochemical stripping voltage is 12~25V and the time is 30min~120min.
[0039] Preferably, the lifting step (2) involves immersing the transparent electrode sheet in the electrochemical solution and placing it below the black phosphorus film, then lifting it out of the liquid surface to transfer the black phosphorus film to the surface of the transparent electrode sheet.
[0040] Preferably, the number of lifting strokes in step (2) is ≥1, more preferably ≥3, and most preferably 5.
[0041] Preferably, the transparent electrode sheet is selected from any one of ITO transparent electrode sheets, graphene transparent electrode sheets, FTO transparent electrode sheets, and ZnO transparent electrode sheets.
[0042] Preferably, the annealing in step (2) is constant temperature annealing at 140~170℃ for 20~50min in an inert atmosphere.
[0043] Preferably, the organic photoelectric response material in step (3) has an absorption spectrum in the range of at least 300~600nm and an emission spectrum bandwidth of ≤60nm.
[0044] Preferably, the organic photoelectric response layer has an emission spectrum with a bandwidth of less than 60 nm between 550 and 750 nm.
[0045] More preferably, the organic photoelectric response material in step (3) is selected from tetracoordinated boron compound organic light-emitting materials, preferably N,C-chelated tetracoordinated boron complexes, and more preferably any one or a combination of at least two boron-nitrogen tetracoordinated boron complexes having a D-π-A structure; D is a donor group, including any one or a combination of at least two of substituted or unsubstituted carbazole groups and substituted or unsubstituted indole groups; A is an acceptor group, including any one or a combination of at least two of substituted or unsubstituted pyridinyl groups.
[0046] Preferably, the dispersant of the organic photoelectric response material dispersion in step (3) is any one or a combination of at least two of chloroform, toluene, dichloromethane, and tetrahydrofuran.
[0047] Preferably, the concentration of the organic photoelectric response material dispersion in step (3) is 3~30 mg / mL.
[0048] Preferably, the number of spin coatings in step (3) is 1 to 9 times, such as 2 times, 3 times, 5 times, 8 times, etc.
[0049] Preferably, the spin coating speed in step (3) is 1000~3000 rpm and the time is 25~50s; more preferably, the spin coating speed is 2000~3000 rpm and the time is 25~40s.
[0050] Preferably, the annealing in step (3) is constant temperature annealing at 50~60℃ for 4~8 minutes.
[0051] Preferably, the method for forming the photocurrent extraction electrode layer in step (4) includes any one or a combination of at least two of the following methods: vapor deposition and magnetron sputtering.
[0052] The third objective of this application is to provide an application of the photoelectric response device as described in the first objective, wherein the photoelectric response device is used in any one of the fields of communication, sensing, detection or medical imaging, preferably in any one of the fields of biomedical imaging, nighttime military reconnaissance, environmental monitoring, fiber optic communication or autonomous driving system for receiving optical signals, and preferably as a broadband photoelectric detection device.
[0053] Compared with the prior art, this application has the following beneficial effects:
[0054] The photoelectric response device provided in this application uses a black phosphorus film layer as the main photoelectric response functional layer, which endows the device with high carrier mobility and a wide absorption spectrum. A specific organic photoelectric response layer is set between the black phosphorus film layer and the current output electrode to effectively isolate water and oxygen in the black phosphorus film layer, improve the device lifespan, and at the same time reduce dark current and improve photoelectric response efficiency. Attached Figure Description
[0055] Figure 1 The image shows the structure of the black phosphorus film / transparent electrode layer obtained in step (2) of Example 1.
[0056] Figure 2 The Raman spectrum of the structure of the black phosphorus film / transparent electrode layer obtained in step (2) of Example 1;
[0057] Figure 3 This is an atomic force microscope (AFM) thickness measurement diagram of the organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure obtained in step (3) of Example 1;
[0058] Figure 4 This is an atomic force microscope (AFM) surface image of the organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure obtained in step (3) of Example 1;
[0059] Figure 5 The image shows the XPS (X-ray photoelectron spectroscopy) characterization of the photoelectric response device obtained in Example 1.
[0060] Figure 6 The photoresponse diagrams of the photoelectric response device obtained in Example 1 at all wavelengths of 532nm, 980nm, 1550nm, 1850nm, and 2200nm are shown.
[0061] Figure 7 The output curve of the photoelectric response device obtained in Example 1 at 0V voltage;
[0062] Figure 8 The output curve of the photoelectric response device obtained in Comparative Example 1 at 0V is shown. Detailed Implementation
[0063] The technical solution of the present invention will be further explained and described below with reference to specific embodiments. However, it should be noted that the specific embodiments are only a specific implementation and explanation of the essence of the technical solution of the present invention, and should not be construed as a limitation on the scope of protection of the present invention.
[0064] The reagents and instruments used in the examples are all commercially available, and the detection methods are conventional methods well known in the art.
[0065] The examples used (Recorded as BN1) (Referred to as BN2) (Recorded as BN3) (Referring to BN4) can be prepared according to the methods disclosed in CN117510529A or the literature “Near-Infrared-Emitting Helically Twisted Conjugated Frameworks, Consisting of Alternant Donor-x-Acceptor Units and Multiple Boron, Atoms” Angewandte Chemie International Edition, 2024, e202417200.
[0066] Bulk black phosphorus, purchased from MK NANO, purity ≥99.999%.
[0067] Example 1
[0068] A method for fabricating a photoelectric response device includes the following steps:
[0069] (1) Tetrabutylammonium acetate (CH3COOTBA) was dissolved in N-vinylpyrrolidone to obtain a solution with a concentration of 0.002 mol / L as an electrolyte and intercalating agent. Bulk black phosphorus (purity >99.999%) was electrochemically exfoliated in the solution. Under an electrochemical exfoliation voltage of 20 V, the exfoliation was carried out for 50 min to obtain black phosphorus nanosheets, which is a black phosphorus nanosheet dispersion. The black phosphorus nanosheet dispersion was added dropwise to pure water, and the black phosphorus nanosheets self-assembled into a black phosphorus film at the gas-liquid interface on the surface of pure water.
[0070] (2) After inserting the transparent electrode sheet (ITO) below the gas-liquid interface, it is pulled up to transfer the black phosphorus film to the surface of the transparent electrode sheet. After drying, a structure with a black phosphorus film transferred is obtained. Then, the structure with a black phosphorus film transferred once is pulled up from the inside of the black phosphorus nanosheet dispersion again to continue transferring the black phosphorus film layer until the black phosphorus film layer is transferred 5 times. After drying, it is annealed at 150°C for 8 minutes to obtain the structure of black phosphorus film layer / transparent electrode layer. Figure 1 Atomic force microscopy (AFM) images of the structure of the black phosphorus film / transparent electrode layer obtained in step (2) of Example 1 are given. Figure 1 It can be seen that the thickness of the black phosphorus film layer is 18.03 nm; Figure 2 Raman spectra of the structure of the black phosphorus film / transparent electrode layer obtained in step (2) of Example 1 are given. Figure 2 It can be seen that the black phosphorus film has a high lattice quality.
[0071] (3) A chloroform dispersion of organic photoelectric response material BN3 (BN3 dispersion concentration 5 mg / mL) was spin-coated onto the surface of the black phosphorus film layer / transparent electrode layer structure. The spin-coating conditions were 1000 rpm spin-coating for 5 s and then 3000 rpm spin-coating for 20 s. After spin-coating, the material was dried and annealed at 50℃ for 5 min to obtain the organic photoelectric response material / black phosphorus film layer / transparent electrode layer structure. Figure 3 Atomic force microscopy (AFM) thickness measurements of the organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure obtained in step (3) of Example 1 are given. Figure 3 It can be seen that the thickness of the organic photoelectric response material layer is 16.95 nm; Figure 4 Atomic force microscopy (AFM) surface images of the organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure obtained in step (3) of Example 1 are given. Figure 4 It can be seen that the surface of the organic photoelectric response material layer is flat and dense;
[0072] (4) A Cr / Au (5 / 50nm) layer is deposited on the surface of the organic photoelectric response material with an organic photoelectric response material / black phosphorus film layer / transparent electrode layer structure using a thermal evaporation coating process assisted by a physical mask (high-precision mixed-mesh copper mesh (opening side length 47μm, rib width 9.2μm)) as a photocurrent extraction electrode layer to obtain the photoelectric response device; the channel length and width of the photoelectric response device are 50μm and 10μm, respectively. The circuit is connected through the photocurrent extraction electrode layer and the transparent electrode layer.
[0073] Figure 5 XPS (X-ray photoelectron spectroscopy) characterization of the photoelectric response device obtained in Example 1 is shown below. Figure 5 As shown, the BP film has good crystal quality and a strong 2p peak of P. After peak splitting, the 2p peak of P was obtained. 3 / 2 With P2p 1 / 2 The binding energies of the two centers are 129.6 eV and 130.25 eV, respectively, corresponding to the binding energies of 0-valent P atoms, indicating that no significant oxidation occurred on the surface of the prepared BP film.
[0074] Example 2
[0075] A method for fabricating a photoelectric response device includes the following steps:
[0076] (1) Tetrabutylammonium acetate (CH3COOTBA) was dissolved in N,N-dimethylformamide to obtain a solution with a concentration of 0.001 mol / L as an electrolyte and intercalating agent. Bulk black phosphorus (purity >99.999%) was electrochemically exfoliated in the solution. Under an electrochemical exfoliation voltage of 15 V, the exfoliation was carried out for 120 min to obtain black phosphorus nanosheets, i.e., a black phosphorus nanosheet dispersion was obtained. The black phosphorus nanosheet dispersion was added dropwise to pure water, and the black phosphorus nanosheets self-assembled into a black phosphorus film at the gas-liquid interface on the surface of pure water.
[0077] (2) After inserting the transparent electrode sheet (ITO) below the gas-liquid interface, it is pulled up to transfer the black phosphorus film to the surface of the transparent electrode sheet. After drying, a structure with a black phosphorus film transferred is obtained. Then, the structure with a black phosphorus film transferred is pulled up again from the inside of the black phosphorus nanosheet dispersion to continue transferring the black phosphorus film layer until 3 black phosphorus film layers are transferred (i.e., 3 black phosphorus film layers). After drying, it is annealed at 150°C for 30 min to obtain a black phosphorus film layer / transparent electrode layer structure with a black phosphorus film layer thickness of about 10 nm.
[0078] (3) On the surface of the black phosphorus film layer of the black phosphorus film layer / transparent electrode layer structure, a chloroform dispersion of organic photoelectric response material BN3 (BN3 dispersion concentration 5 mg / mL) was spin-coated. The spin-coating conditions were 2800 rpm for 35 s. After spin-coating, the material was dried and annealed at 50℃ for 5 min to obtain the structure of organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer. The thickness of organic photoelectric response material layer was 12.05 nm.
[0079] (4) A photocurrent extraction electrode layer is formed on the surface of the organic photoelectric response material with the structure of organic photoelectric response material / black phosphorus film layer / transparent electrode layer by a thermal evaporation coating process assisted by a physical mask (high precision mixed mesh copper mesh (opening side length 47μm, rib width 9.2μm)) to obtain the photoelectric response device; the channel length and width of the photoelectric response device are 50μm and 10μm, respectively.
[0080] Example 3
[0081] A method for fabricating a photoelectric response device includes the following steps:
[0082] (1) Tetrabutylammonium acetate (CH3COOTBA) was dissolved in N-vinylpyrrolidone to obtain a solution with a concentration of 0.003 mol / L as an electrolyte and intercalating agent. Bulk black phosphorus (purity >99.999%) was electrochemically exfoliated in the solution. Under an electrochemical exfoliation voltage of 20 V, the exfoliation was carried out for 30 min to obtain black phosphorus nanosheets, i.e., a black phosphorus nanosheet dispersion was obtained. The black phosphorus nanosheet dispersion was added dropwise to pure water, and the black phosphorus nanosheets self-assembled into a black phosphorus film at the gas-liquid interface on the surface of pure water.
[0083] (2) After inserting the transparent electrode sheet (ITO) below the gas-liquid interface, it is pulled up to transfer the black phosphorus film to the surface of the transparent electrode sheet. After drying, a structure with a black phosphorus film transferred is obtained. Then, the structure with a black phosphorus film transferred is pulled up again from the inside of the black phosphorus nanosheet dispersion to continue transferring the black phosphorus film layer until 5 black phosphorus film layers are transferred. After drying, it is annealed at 150°C for 8 minutes to obtain a structure of black phosphorus film layer / transparent electrode layer with a black phosphorus film layer thickness of 17.93 nm.
[0084] (3) A chloroform dispersion of organic photoelectric response material BN3 (BN3 dispersion concentration 30 mg / mL) was spin-coated onto the surface of the black phosphorus film layer / transparent electrode layer structure. The spin-coating conditions were 2800 rpm for 35 s, followed by drying and annealing at 50 °C for 5 min to obtain the organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure. The thickness of the organic photoelectric response material layer was 20.5 nm.
[0085] (4) A photocurrent extraction electrode layer is formed on the surface of the organic photoelectric response material with the structure of organic photoelectric response material / black phosphorus film layer / transparent electrode layer by a thermal evaporation coating process assisted by a physical mask (high precision mixed mesh copper mesh (opening side length 47μm, rib width 9.2μm)) to obtain the photoelectric response device; the channel length and width of the photoelectric response device are 50μm and 10μm, respectively.
[0086] Examples 4-6
[0087] The difference in Example 1 is that BN3 is replaced by BN1 (Example 4), BN2 (Example 5), and BN4 (Example 6) in equal molar amounts.
[0088] Comparative Example 1
[0089] A method for fabricating a photoelectric response device differs from Example 1 only in step (4):
[0090] (4) An electrode layer is formed on the surface of the organic photoelectric response material with a Cr / Au (5 / 50nm) structure, which serves as the organic photoelectric response material / black phosphorus film layer / transparent electrode layer, by a thermal evaporation coating process assisted by a physical mask (high-precision mixed-mesh copper mesh (opening side length 47μm, rib width 9.2μm)). The photoelectric response device is obtained by depositing a Cr / Au (5 / 50nm) structure on the surface of the organic photoelectric response material / black phosphorus film layer / transparent electrode layer. The channel length and width of the photoelectric response device are 50μm and 10μm, respectively. The circuit connection of the photoelectric response device is all connected through the electrode layer.
[0091] Performance testing:
[0092] (1) Spectral response: The photoelectric response devices obtained in the examples and comparative examples were placed in room temperature and vacuum environments, respectively. One end of the detector was connected to the photocurrent extraction electrode layer, and the other end was connected to the transparent electrode layer (vertical heterojunction array device). A fixed bias voltage V was applied. ds =0.1V, the vertical device was subjected to laser irradiation across the entire wavelength range from 532nm to 2200nm, and the photoelectric response characteristics of the device in the visible to short-wave infrared range (532nm, 980nm, 1550nm, 1850nm, 2200nm) were investigated. Figure 6 The photoresponse diagrams of the photoelectric response device obtained in Example 1 at all wavelengths of 532nm, 980nm, 1550nm, 1850nm, and 2200nm are presented. From... Figure 6 It can be seen that the photoelectric response device provided in Example 1 has a photoelectric response in the range of 532~2200nm, especially at 1550nm, the photoelectric response is as high as 85.87nA. Table 1 shows the absorption spectrum range of the photoelectric response devices of the examples and comparative examples.
[0093] (2) Dark current
[0094] The photoresponse devices obtained in the examples and comparative examples were placed in room temperature, vacuum, and dark environments, respectively, and tested with a bias voltage range of -0.1V to 0.1V (sweep in 0.01V steps). The photoresponse device provided in the examples exhibited excellent linear output characteristics, confirming excellent ohmic contact interface, and a dark current of less than 0.1μA. Figure 7 The output curve of the photoelectric response device obtained in Example 1 at 0V is given, and it can be seen that the dark current is 0.06μA. Figure 8 The output curve of the photoelectric response device obtained in Comparative Example 1 at 0V is shown. It can be seen that the dark current in the output curve at 0V is 0.80μA, which is much larger than the dark current in Example 1.
[0095] The test results are shown in Table 1.
[0096] Table 1
[0097]
[0098] The performance test results show that the photoelectric response device provided in this application has a spectral range of 532~220nm and a dark current of less than 0.1μA, which significantly suppresses the dark current and improves the signal-to-noise ratio and detection sensitivity.
[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A photoelectric response device, characterized in that, The photoelectric response device includes a transparent electrode layer, and a black phosphorus film layer, an organic photoelectric response layer, and a photocurrent extraction electrode layer are sequentially disposed on one side of the transparent electrode layer. The organic photoelectric response layer has an absorption spectrum in the range of at least 300~600nm and an emission spectrum bandwidth of ≤60nm.
2. The photoelectric response device as described in claim 1, characterized in that, The organic photoelectric response layer has an emission spectrum with a bandwidth of less than 60 nm between 550 and 750 nm; Preferably, the organic photoelectric response layer material is a four-coordinate boride organic light-emitting material, preferably an N,C-chelate four-coordinate boron complex, and more preferably any one or a combination of at least two boron-nitrogen four-coordinate boron complexes having a D-π-A structure; wherein D is a donor group, including any one or a combination of at least two substituted or unsubstituted carbazole groups and substituted or unsubstituted indole groups; and wherein A is an acceptor group, including any one or a combination of at least two substituted or unsubstituted pyridinyl groups. Preferably, the organic photoelectric response material comprises one or a combination of at least two of the following materials: 。 3. The photoelectric response device as described in claim 1 or 2, characterized in that, The transparent electrode includes any one of ITO transparent electrode, graphene transparent electrode, FTO transparent electrode, and ZnO transparent electrode; Preferably, the black phosphorus film is formed by the self-assembly of black phosphorus nanosheets at the gas-liquid interface; Preferably, the ratio of the thickness of the black phosphorus film layer to the thickness of the organic photoelectric response layer is 0.75~15; Preferably, the thickness of the black phosphorus film layer is 15nm~30nm.
4. The photoelectric response device as described in any one of claims 1 to 3, characterized in that, The thickness of the organic photoelectric response layer is 2nm~20nm; Preferably, the photocurrent extraction electrode layer includes any one of a Cr / Au layer, an Ag layer, and a tungsten metal layer.
5. A method for fabricating a photoelectric response device as described in any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: (1) Electrochemically exfoliate the bulk black phosphorus in the dispersant to obtain black phosphorus nanosheets and obtain a black phosphorus nanosheet dispersion. Add the black phosphorus nanosheet dispersion to pure water, and the black phosphorus nanosheets self-assemble on the surface of pure water to form a black phosphorus film. (2) After placing the transparent electrode sheet below the gas-liquid interface, pull it up to transfer the black phosphorus film to the surface of the transparent electrode sheet. After drying, anneal to obtain the structure of black phosphorus film layer / transparent electrode layer. (3) Spin-coating an organic photoelectric response material dispersion onto the surface of the black phosphorus film layer in the structure of black phosphorus film layer / transparent electrode layer, drying, and annealing to obtain the structure of organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer; (4) A photocurrent extraction electrode layer is formed on the surface of an organic photoelectric response material with an organic photoelectric response material layer / black phosphorus film layer / transparent electrode layer structure to obtain the photoelectric response device; Preferably, the photocurrent extraction electrode layer has a patterned structure, and more preferably a patterned structure of a block array.
6. The preparation method according to claim 5, characterized in that, The dispersant in step (1) includes any one or a combination of at least two of N,N-dimethylformamide, propylene carbonate, dimethyl sulfoxide, N-methylpyrrolidone, and N-vinylpyrrolidone; Preferably, the bulk black phosphorus is black phosphorus crystal with a purity ≥99.999%; Preferably, the electrochemical stripping solution is a tetrabutylammonium acetate solution, and more preferably a tetrabutylammonium acetate solution with a concentration of 0.001~0.003 mol / L; Preferably, the volume of the electrochemical stripping solution is 10 mL to 20 mL; Preferably, the electrochemical stripping voltage is 12~25V and the time is 30min~120min.
7. The preparation method according to claim 5 or 6, characterized in that, The lifting step (2) involves inserting the transparent electrode sheet into the electrochemical solution and placing it below the black phosphorus film, then vertically lifting it out of the liquid surface to transfer the black phosphorus film to the surface of the transparent electrode sheet. Preferably, the number of lifting movements in step (2) is ≥1 time, more preferably ≥3 times, and most preferably 5 times; Preferably, the transparent electrode sheet is selected from any one of ITO transparent electrode sheets, graphene transparent electrode sheets, FTO transparent electrode sheets, and ZnO transparent electrode sheets; Preferably, the annealing in step (2) is constant temperature annealing at 140~170℃ for 20~50min in an inert atmosphere.
8. The preparation method according to any one of claims 5 to 7, characterized in that, The organic photoelectric response material described in step (3) has an absorption spectrum in the range of at least 300~600nm and an emission spectrum bandwidth of ≤60nm; Preferably, the organic photoelectric response layer has an emission spectrum with a bandwidth of less than 60 nm between 550 and 750 nm; More preferably, the organic photoelectric response material in step (3) is selected from tetracoordinate boride organic light-emitting materials, preferably N,C-chelate tetracoordinate boron complexes, and more preferably any one or a combination of at least two boron-nitrogen tetracoordinate boron complexes having a D-π-A structure; D is a donor group, including any one or a combination of at least two of substituted or unsubstituted carbazole groups and substituted or unsubstituted indole groups; A is an acceptor group, including any one or a combination of at least two of substituted or unsubstituted pyridinyl groups. Preferably, the dispersant of the organic photoelectric response material dispersion in step (3) is any one or a combination of at least two of chloroform, toluene, dichloromethane, and tetrahydrofuran; Preferably, the concentration of the organic photoelectric response material dispersion in step (3) is 3~30 mg / mL; Preferably, the spin coating in step (3) is performed 1 to 9 times; Preferably, the spin coating speed in step (3) is 1000~3000 rpm and the time is 25~50s; more preferably, the spin coating speed is 2000~3000 rpm and the time is 25~40s. Preferably, the annealing in step (3) is constant temperature annealing at 50~90℃ for 5~30 minutes.
9. The preparation method according to any one of claims 5 to 8, characterized in that, The method for forming the photocurrent extraction electrode layer in step (4) includes any one or a combination of at least two of the following methods: vapor deposition and magnetron sputtering.
10. The use of a photoelectric response device as described in any one of claims 1 to 3, characterized in that, The photoelectric response device is used in any one of the fields of communication, sensing, detection or medical imaging, preferably in any one of the fields of biomedical imaging, nighttime military reconnaissance, environmental monitoring, optical fiber communication or autonomous driving system optical signal reception, and preferably as a broadband photoelectric detection device.