Tunable near-infrared image sensor

Abstract

The invention discloses a tunable near-infrared image sensor, the tunable near-infrared image sensor is applied to biological feature recognition, and the tunable near-infrared image sensor comprises a plurality of arrayed pixel sensing units; the pixel sensing unit comprises a semitransparent first electrode and a transparent second electrode, the total reflection second electrode is arranged opposite to the first electrode, and the total reflection second electrode and the first electrode form a microcavity used for enhancing the spectral response of a near-infrared target wave band; the photoelectric conversion layer is arranged between the first electrode and the second electrode, and a section of absorption edge of an absorption wave band of the photoelectric conversion layer serves as a near-infrared target wave band to be enhanced by the microcavity in spectral response; the optical modulation layer is used for absorbing and filtering light of other wave bands except the near-infrared target wave band and transmitting carriers, and is arranged between the first electrode and the photoelectric conversion layer; and the cavity length of the microcavity is regulated and controlled by regulating the thickness of the optical modulation layer, so that the spectral response of the near-infrared target wave band is enhanced, and the peak wave band is regulated and controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optoelectronic devices, and more particularly to a tunable near-infrared image sensor. BACKGROUND

[0002] With the development of artificial intelligence and intelligent terminals, facial feature-based identity recognition has been widely applied in the fields of security, payment and human-computer interaction. In order to improve the accuracy and anti-interference ability of recognition, near-infrared band imaging has gradually attracted attention. Compared with visible light, near-infrared light has stronger penetration and stability, which can avoid the interference of environmental light, so as to realize more reliable feature recognition under weak light or complex background conditions.

[0003] Most of the existing near-infrared image sensors are based on inorganic materials such as silicon or InGaAs, which have certain advantages in performance, but generally have the following shortcomings: complex preparation process, high cost, lack of flexibility and scalability, and difficult to meet the needs of new portable or wearable devices. Organic photodetectors have gradually attracted attention due to their simple structure, low preparation cost and excellent mechanical flexibility. However, the absorption capacity of conventional organic materials in the near-infrared region is limited, and the absorption edge absorption signal is weak, which leads to insufficient sensitivity of the device in near-infrared feature recognition. At the same time, due to the wide response spectrum, it is difficult to selectively enhance specific wavelengths, and the device is easily disturbed by background light and multi-order interference peaks, which limits its application in specific recognition.

[0004] Current research attempts to use external filters or complex optical cavity structures to improve narrowband response, but these methods usually increase the thickness and preparation complexity of the device, reducing the integration and stability of the system. For example, by stacking interference filters or bandpass filters in front of the detector, transmission enhancement can be achieved in specific wavebands. However, such external filters require additional packaging, which not only increases the thickness and cost of the system, but also easily causes transmission peak drift when the incident angle changes. Using a multi-layer dielectric Bragg reflector (DBR) to construct a microcavity can achieve good narrowband selectivity, but it often requires precise stacking of dozens of high and low refractive index materials, which is complex and difficult to realize miniaturized integration; using a thicker Fabry-Pérot cavity structure or introducing external optical components (such as waveguides, microlens arrays, etc.) can also improve the light field distribution, but inevitably leads to an increase in device size, difficulty in optical alignment, and a decrease in stability. Therefore, how to effectively enhance the absorption of specific near-infrared wavelengths while suppressing the influence of irrelevant wavebands and interference orders through effective optical regulation means under the premise of maintaining a simple device structure, so as to realize efficient narrowband specific recognition, is still a technical problem that needs to be solved in this field. SUMMARY

[0005] The application provides a tunable near-infrared image sensor, which can enhance the absorption of specific near-infrared wavelengths by effective optical regulation means while suppressing the influence of irrelevant wave bands and interference orders, so as to realize efficient narrow-band specific identification under the premise of keeping the device structure simple.

[0006] To solve the above technical problems, the application adopts the technical scheme of:

[0007] A tunable near-infrared image sensor applied to biological feature recognition, comprising a plurality of pixel sensing units forming an image array; the pixel sensing unit comprises:

[0008] a semi-transparent first electrode;

[0009] a fully reflective second electrode, which is arranged opposite to the first electrode and forms a microcavity with the first electrode for enhancing the spectral response of the near-infrared target wave band;

[0010] a photoelectric conversion layer arranged between the first electrode and the second electrode, which absorbs a section of the absorption edge of the wave band as the near-infrared target wave band and enhances the spectral response of the near-infrared target wave band by the microcavity;

[0011] an optical modulation layer for absorbing and filtering other wave bands except the near-infrared target wave band and transmitting carriers, which is arranged between the first electrode and the photoelectric conversion layer; and the optical modulation layer is used to regulate the cavity length of the microcavity by adjusting the thickness of the optical modulation layer, so as to enhance the spectral response of the near-infrared target wave band.

[0012] Preferably, the near-infrared target wave band refers to a narrow-band wave band with the maximum external quantum efficiency at the target wavelength.

[0013] Further, the target wavelength is located within 800 nm-3000 nm.

[0014] Preferably, the transmittance of the first electrode to the light of the target wave band is greater than or equal to 70%, and the transmittance of the first electrode to the light of the target wave band reflected by the second electrode is less than or equal to 5%.

[0015] Further, the structure of the first electrode comprises a thin-layer metal electrode, a thin-layer metal electrode / metal oxide electrode, a conductive polymer electrode, a carbon-based transparent electrode, a DBR / thin-layer metal electrode or a DBR / metal oxide electrode.

[0016] Preferably, the material of the optical modulation layer comprises an electron donor material that can be used for solution processing, an electron donor material that can be used for thermal evaporation, an electron acceptor material that can be used for solution processing, an electron acceptor material that can be used for thermal evaporation, a phthalocyanine material, an organic dye material, and an inorganic or high polymer filter material.

[0017] Preferably, the cavity length of the microcavity is in the range of 200-1000 nm, which satisfies the optical resonance condition 2nL=mλ0, where n is the effective refractive index in the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength; so as to ensure stable narrow-band enhancement at the target wavelength λ0.

[0018] Preferably, the thickness of the optical modulation layer is 50-300 nm, and the total cavity length satisfies the optical resonance condition 2nL=mλ0. By adjusting the thickness of the optical modulation layer, the total cavity length of the microcavity is matched with the resonance condition of the target wavelength, so as to flexibly adjust the narrow-band enhancement effect in different wavelength ranges, thereby improving the adaptability and application expansibility of the device.

[0019] Preferably, the pixel sensing unit further comprises a first interface functional layer between the optical modulation layer and the photoelectric conversion layer, and / or a second interface functional layer between the second electrode and the photoelectric conversion layer; the first interface functional layer or the second interface functional layer can be used to optimize the carrier injection, transmission and collection process, thereby improving the response efficiency and long-term stability of the device.

[0020] Preferably, the top of the pixel sensing unit further integrates a microlens for realizing a 120° focusing viewing angle.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The present application introduces a Fabry-Perot (FP) cavity structure in the device, which is formed by two opposite electrodes, can produce light field enhancement effect at a specific resonance wavelength, thereby significantly improving the absorption ability of the absorption band of the photoelectric conversion layer in the absorption edge region, i.e. improving the spectral response. At the same time, for the non-target order enhancement signal caused by the FP cavity, the optical modulation layer can be used to suppress it, effectively avoiding the interference of irrelevant wavebands. The present application not only can realize narrow-band near-infrared specific recognition, but also has the advantages of simple structure, high integration and clear enhancement peak. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a device structure schematic diagram of a tunable near-infrared image sensor provided by the present application.

[0024] Figure 2 is another device structure schematic diagram of a tunable near-infrared image sensor provided by the present application.

[0025] Figure 3 is still another device structure schematic diagram of a tunable near-infrared image sensor provided by the present application.

[0026] Figure 4is a device structure schematic diagram of a tunable near-infrared image sensor provided by the present application.

[0027] Figure 5 is a spectral external quantum efficiency diagram of the photoelectric conversion layer without microcavity enhancement provided by the present application.

[0028] Figure 6 is a spectral external quantum efficiency diagram of the photoelectric conversion layer with microcavity enhancement provided by the present application.

[0029] Figure 7 is a spectral external quantum efficiency diagram of the optical modulation layer provided by the present application.

[0030] Figure 8 is a spectral external quantum efficiency diagram of the tunable near-infrared image sensor.

[0031] Figure 9 is a spectral external quantum efficiency diagram of the photoelectric conversion layer without microcavity enhancement provided by example 5.

[0032] Figure 10 is a spectral external quantum efficiency diagram of the photoelectric conversion layer with microcavity enhancement provided by example 5.

[0033] Figure 11 is a spectral external quantum efficiency diagram of the tunable near-infrared image sensor provided by example 5.

[0034] In the figure, 1-first electrode, 2-second electrode, 3-photoelectric conversion layer, 4-optical modulation layer, 5-first interface functional layer, 6-second interface functional layer, 7-substrate, 8-micro-lens. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application. The present application will be described in detail below with reference to the drawings and specific embodiments.

[0036] It should be understood that when used in the present specification, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0037] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms.

[0038] It should also be further understood that the term "and / or" as used in this specification refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0039] Example

[0040] like Figure 1 As shown, a tunable near-infrared image sensor is used for biometric identification. The tunable near-infrared image sensor includes multiple pixel sensing units forming an image array; each pixel sensing unit includes:

[0041] A semi-transparent first electrode;

[0042] The total internal reflection second electrode is disposed opposite to the first electrode and forms a microcavity with the first electrode to enhance the spectral response of the near-infrared target band;

[0043] A photoelectric conversion layer is disposed between the first electrode and the second electrode. A section of its absorption band is used as a near-infrared target band, and its spectral response is enhanced by a microcavity. The near-infrared target band refers to a narrow band with the maximum external quantum efficiency at the target wavelength.

[0044] An optical modulation layer, used to absorb and filter light in bands other than the near-infrared target band and to transport charge carriers, is disposed between the first electrode and the photoelectric conversion layer. The cavity length of the microcavity is controlled by adjusting the thickness of the optical modulation layer, thereby enhancing the spectral response of the near-infrared target band. The near-infrared target band refers to a narrowband band with maximum external quantum efficiency at the target wavelength.

[0045] This invention introduces a Fabry-Perot (FP) cavity structure (i.e., a microcavity) into the device, formed by two opposing electrodes. This structure generates an optical field enhancement effect at a specific resonant wavelength, significantly improving the absorption capability of the photoelectric conversion layer in the absorption edge region, thus enhancing the spectral response. Simultaneously, non-target order enhancement signals caused by the FP cavity can be suppressed using an optical modulation layer, effectively avoiding interference from irrelevant bands. This invention not only achieves narrowband near-infrared specific recognition but also possesses advantages such as simple structure, high integration, and clear enhancement peak differentiation.

[0046] In the embodiment, the target wavelength is within 800 nm-3000 nm, such as 800 nm, 850 nm, 900 nm, 940 nm, 980 nm, 1000 nm, or 1100 nm, 1500 nm, 1800 nm, etc. The full width at half maximum of the narrow band is 50 nm-150 nm, such as 50 nm, 100 nm, 150 nm. The biometric identification includes face recognition, fingerprint recognition, etc. The target band for face recognition can be set according to the target band (such as 940 nm, or 980 nm, etc.) required by face recognition, and the spectral response of the target band can be enhanced by adjusting the cavity length of the microcavity.

[0047] In the embodiment, when the wavelength of the incident light satisfies the integer multiple of the cavity length (i.e. resonance condition), the light at the wavelength can be constructively interfered in the microcavity, i.e. the light at the target wavelength entering the microcavity will be repeatedly reflected and coherently superimposed. Since the electric field strength is greatly enhanced, the absorption rate of the photoelectric conversion layer to the target band corresponding to the target wavelength is significantly improved, thereby improving the spectral response of the photoelectric conversion layer to the target band, i.e. improving the external quantum efficiency (EQE). When the wavelength of the incident light satisfies the integer multiple of the cavity length of the microcavity, the incident light can be constructively interfered in the microcavity, and there will be non-target order enhanced signals. In order to obtain the target band corresponding to the target wavelength, the optical modulation layer is introduced between the first electrode and the photoelectric conversion layer. The functions of the optical modulation layer include: 1. Absorbing and filtering the light of other bands except the target band, including the light of the non-target order band; 2. As a cavity length control layer, the cavity length (i.e. the distance between the first electrode and the second electrode) is adjusted, so as to adjust the enhanced target band.

[0048] In addition, the microcavity structure is used to effectively excite the absorption edge of the photoelectric conversion layer, i.e. the absorption cutoff edge of the absorption band. That is, the near-infrared target band is enhanced at the absorption cutoff edge of the absorption band, and by exciting the target band at the absorption cutoff edge of the absorption band, the light of other bands is absorbed and filtered by the optical modulation layer.

[0049] In the embodiment, the cavity length of the microcavity is within 200-1000 nm, which satisfies the optical resonance condition 2nL=mλ0, where n is the effective refractive index in the cavity, L is the cavity length, m is an integer, and λ0is the target wavelength. The spectral response of different target bands can be enhanced by adjusting the cavity length of the microcavity. Further, the target wavelength is preferably 940±40 nm, which meets the needs of near-infrared applications such as face recognition.

[0050] In the embodiment, when working at the first order resonance (m=1) of 940 nm, the optical modulation layer thickness is preferably 130-160 nm, and the corresponding total cavity length is about 240 nm; when working at the second order resonance (m=2) of 940 nm, the optical modulation layer thickness is preferably 370-400 nm, and the corresponding total cavity length is about 490 nm; when working at the third order resonance (m=3) of 940 nm, the optical modulation layer thickness is preferably 600-700 nm, and the corresponding total cavity length is about 680 nm. Through the above thickness adjustment, different resonance orders can be flexibly selected under the same device structure, so as to realize the narrow-band enhancement of the 940 nm near-infrared band.

[0051] In the embodiment, the absorption response of the photoelectric conversion layer reaches the near-infrared band, that is, the absorption edge of the absorption band of the photoelectric conversion layer is in the near-infrared band.

[0052] The photoelectric conversion layer comprises an organic semiconductor in the form of a single-phase film or a D / A bulk heterojunction blended film, an inorganic semiconductor or a compound semiconductor in the form of a single-phase or quantum dot nanoparticle, or a combination in a mixed form or a thin film stack form; wherein D represents an organic molecule acting as an electron donor; A represents an organic molecule acting as an electron acceptor;

[0053] The inorganic semiconductor comprises Si, Ge, SiGe, CuInS x Se 2-x (0≤x≤2), CuInGa(S, Se), PbS, PbI2, PBI3, InGaAs, or a single-phase film;

[0054] The organic semiconductor comprises one or more organic molecules acting as an electron donor (D) and one or more organic molecules acting as an electron acceptor (A) to form a D / A organic blend.

[0055] In the case that the photoelectric conversion layer comprises organic materials, the photoelectric conversion layer can have one of the following four forms:

[0056] (1) formed by an organic donor material;

[0057] (2) formed by an organic acceptor material;

[0058] (3) formed by a laminated structure of an organic donor material layer and an organic acceptor material layer;

[0059] an organic donor material layer, a mixed layer of an organic donor material and an organic acceptor material (bulk heterostructure), and a laminated structure of an organic acceptor material layer;

[0060] The layer stack of the organic donor material layer and the mixed layer of the organic donor material and the organic acceptor material (bulk heterostructure) is formed, or

[0061] The layer stack of the organic donor material layer and the mixed layer of the organic donor material and the organic acceptor material (bulk heterostructure) is formed; and

[0062] The mixed structure of the organic donor material and the organic acceptor material (bulk heterostructure) is formed. However, in each configuration, the layer stack order can be changed as appropriate.

[0063] In one specific embodiment, the material of the optical modulation layer includes one or more of the following: an electron donor material that can be solution-processed (such as P3HT, PTB7, PM6), an electron donor material that can be thermally evaporated (such as

[0064] TAPC, NPB), an electron acceptor material that can be solution-processed (such as Y6, ITIC-based non-fullerene acceptor), an electron acceptor material that can be thermally evaporated (such as C 60 , C 70 , BPhen), a phthalocyanine-based material (such as PbPc, ZnPc), an organic dye-based material (such as cyanine dye, porphyrin compound), and an inorganic or high-molecular filter material (such as TiO2, SiO2, polyimide).

[0065] The optical modulation layer can use an electron donor material or an electron acceptor material alone, in which case the thickness of the optical modulation layer is required to meet the requirement of sufficient absorption and filtering of light other than the target wavelength band, so that the light cannot reach the photoelectric conversion layer. Alternatively, at least one electron donor material and at least one electron acceptor material can be blended to form the optical modulation layer. Since the electron donor material and the electron acceptor material are blended, in order to avoid the dissociation of excitons generated by the absorption of light and the transmission to the photoelectric conversion layer, thereby causing signal interference, the optical modulation layer should be set to a relatively thick thickness, so that the excitons generated by the absorption of light in the optical modulation layer are recombined during the transmission process and cannot be transmitted to the photoelectric conversion layer, thereby achieving sufficient absorption and filtering of light other than the target wavelength band, so that the light cannot reach the photoelectric conversion layer.

[0066] The thickness of the optical modulation layer is 50-300 nm, and the total cavity length meets the optical resonance condition 2nL = mλ0.

[0067] The preparation of the photoelectric conversion layer and the optical modulation layer is selected from solution film formation or vacuum thermal evaporation deposition.

[0068] In one specific embodiment, in order to make the light of the target waveband incident to the photoelectric conversion layer with lower loss, and reflect the light of the target waveband as much as possible, the transmittance of the first electrode to the light of the target waveband is greater than or equal to 70%, and the transmittance of the second electrode to the light of the target waveband reflected by the second electrode is less than or equal to 5%.

[0069] That is, when the incident light (including the light of the target waveband) is incident from the outside to the image sensor, the transmittance of the first electrode to the light of the target waveband is greater than or equal to 70%, such as 70%, or 80%, or 90%. When the light is incident into the image sensor, the second electrode has total reflectivity, so the light that is not absorbed is reflected, and the transmittance of the first electrode to the light of the target waveband reflected back is less than or equal to 5%, that is, as much as possible, the light of the target waveband is reflected back to the photoelectric conversion layer, so that the light of the target waveband is reflected back and forth in the microcavity, and is fully absorbed by the photoelectric conversion layer, thereby improving the spectral response.

[0070] Specifically, the structure of the first electrode is a metal oxide transparent electrode (such as ITO, AZO, FTO, or SnO2), a thin layer of metal electrode (such as Ag, Au, Al, Ti, Ni, Cr or Cu), a thin layer of metal / metal oxide composite electrode (such as ITO / Ag / ITO, AZO / Ag / AZO, or FTO / Ag / FTO, ITO / Au / ITO), a conductive polymer electrode (such as PEDOT:PSS), a carbon-based transparent electrode (such as single-layer or multi-layer graphene, carbon nanotube film), and a dielectric Bragg mirror / transparent conductive electrode composite structure (such as DBR / ITO, DBR / AZO, or DBR / FTO). In the present embodiment, the fully reflective second electrode is made of opaque conductive material, which includes one or more of silver, aluminum, gold, copper, nickel, titanium, and chromium. The thickness of the fully reflective second electrode is not less than 50 nm. The thickness of the second electrode is less than or equal to 5 μm. Specifically, the second electrode can be 50 nm, 80 nm, 100 nm, 150 nm, 200 nm or other thickness.

[0071] In addition, it should be noted that the first electrode can be a cathode or an anode, and the second electrode can be an anode or a cathode accordingly.

[0072] The preparation of the electrode is independently selected from one or more of vacuum thermal evaporation, electron beam evaporation, molecular beam evaporation or plasma sputtering, atomic layer deposition or liquid film formation and reduction conversion, electroplating or electrodeposition.

[0073] In one specific embodiment, the pixel sensing unit further comprises a first interface functional layer between the optical modulation layer and the photoelectric conversion layer, and / or a second interface functional layer between the second electrode and the photoelectric conversion layer.

[0074] The interface functional layer includes a charge blocking layer, a charge transport layer, etc. At this time, the total cavity length of the microcavity is determined by the total thickness of the interface functional layer, the photoelectric conversion layer, and the optical modulation layer. The thickness of the optical modulation layer can be changed to adjust the cavity length of the microcavity, and thus the spectral response of light in the target waveband is enhanced.

[0075] When the first electrode is a cathode and the second electrode is an anode, the first interface functional layer can include an electron transport layer or a hole blocking layer; and the second interface functional layer can include a hole transport layer or an electron blocking layer.

[0076] When the first electrode is an anode and the second electrode is a cathode, the first interface functional layer can include a hole transport layer or an electron blocking layer; and the second interface functional layer can include an electron transport layer or a hole blocking layer.

[0077] For example, as shown in FIG. 1, the pixel sensing unit includes, from top to bottom, a first electrode, an optical modulation layer, a first interface functional layer, a photoelectric conversion layer, a second interface functional layer, a second electrode, and a substrate. Figure 2

[0078] At this time, the pixel sensing unit is a top incident structure, and the substrate can be made of an opaque material; the incident light is incident from the side of the first electrode.

[0079] Of course, the pixel sensing unit can also be a bottom incident structure, in which case the pixel sensing unit includes, from bottom to top, a transparent substrate, a first electrode, an optical modulation layer, a first interface functional layer, a photoelectric conversion layer, a second interface functional layer, and a second electrode.

[0080] For example, as shown in FIG. 1, the pixel sensing unit includes, from top to bottom, a first electrode, an optical modulation layer, a first interface functional layer, a photoelectric conversion layer, a second electrode, and a substrate. Figure 3 Alternatively, the pixel sensing unit includes, from top to bottom, a first electrode, an optical modulation layer, a photoelectric conversion layer, a second interface functional layer, a second electrode, and a substrate.

[0081] Similarly, a top incident device structure can also be used, or a bottom incident device structure can also be used.

[0082] In this embodiment, the material of the electron transport layer or the hole blocking layer can be independently selected from one or more of the organic compound 1, the inorganic compound 1, or a combination thereof.

[0083]

[0084] ​​The organic compound 1 includes fullerene and its derivatives, 4,7-diphenyl-1,10-phenanthroline, polyethyleneimine, polyethyloxyl ethyleneimine, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, [9,9-dioctylfluorene 9,9-bis(N,N-dimethylaminopropyl)fluorene], brominated [9,9-dioctylfluorene 9,9-bis(N,N-dimethylaminopropyl)fluorene], 8-hydroxyquinolinol lithium, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, bis(2-methyl-8-quinolinolato)4-phenylphenol aluminum, 1,3,5-tris[(3-pyridyl)phenyl]benzene, naphthalene diimide bromide, or a mixture or composite of the above materials.

[0085] The inorganic compound 1 includes zinc oxide, tin oxide, aluminum-doped zinc oxide, magnesium-doped zinc oxide, gallium-doped zinc oxide, titanium oxide, tantalum oxide, zinc sulfide, chromium sulfide, or a mixture or composite of the above materials.

[0086] The material of the hole transport layer or the electron blocking layer can be independently selected from one or more of the organic compound 2, the inorganic compound 2, or a combination thereof.

[0087] The organic compound 2 includes one or more of 4,4'-cyclohexylidenebis[N,N'-di(4-methylphenyl)benzenamine], N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine, N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-2,7-diamino-9,9-spirobifluorene, 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4',4"-tris(carbazol-9-yl)triphenylamine, poly(4-butyltriphenylamine), polyvinylcarbazole, polystyrene-N,N'-diphenyl-N,N'-bis-(3-methylphenyl)-(1,1)-biphenyl-4,4'-diamine perfluorocyclobutane, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), poly[bis(4-phenyl)(4-butylphenyl)amine].

[0088] The inorganic compound 2 includes tungsten oxide, molybdenum oxide, vanadium oxide, chromium oxide, nickel oxide, copper oxide, cuprous oxide, cuprous thiocyanate, copper sulfide, copper iodide, copper phthalocyanine, or a mixture or composite of the above materials.

[0089] The preparation of the interface functional layer is independently selected from one or more of solution film formation, sol-gel film formation, vacuum thermal evaporation, atomic layer deposition, chemical vapor deposition, electrodeposition, anodic oxidation method.

[0090] The top of the pixel sensing unit is also integrated with a microlens that realizes a 120° focusing viewing angle.

[0091] The top of the pixel sensing unit is integrated with a microlens, which can ensure that the incident light within the focusing visual angle of 120° enters the microcavity in a vertical direction, thereby reducing the target peak wavelength deviation caused by light crosstalk and effectively reducing the half-peak width.

[0092] The microlens is made of a super-hemispherical or optimized aspherical structure of high refractive index material (n>1.8). The diameter needs to be much larger than the pixel size (preferably 2 times or more), and the radius of curvature needs to be strictly optimized through optical simulation to ensure that the light spot can be effectively constrained within the detection area within the entire visual angle range.

[0093] The high refractive index material (n>1.8) includes titanium dioxide (TiO2), silicon nitride (Si3N4), high molecular materials (such as polyimide), etc.

[0094] In the present application, the substrate is integrated with a pixel readout circuit inside. If an example of the constituent material of the substrate is cited, inorganic materials such as glass, sapphire, titanium dioxide, etc.; organic materials such as polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, fluororesin, chlorovinyl, polyethylene, cellulose, polyvinylidene chloride, aromatic polyamide, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, etc.; paper materials such as paper, synthetic paper, etc.; composite materials such as materials obtained by surface coating or lamination of metals such as stainless steel, titanium, aluminum, etc. to impart insulation; and the like can be mentioned. The constituent material of the substrate can be used alone or in combination of two or more in any combination and ratio.

[0095] The shape and size of the substrate are not limited and can be arbitrarily set. If the thickness of the substrate is too thin, the strength is insufficient to meet the function as a support member, and if it is too thick, the cost increases. The substrate is usually a film or a plate with a thickness of about 10 μm to 50 mm.

[0096] In addition, the pixel sensing unit further includes a packaging layer to ensure stable operation of the sensor in various use environments and during the target service life. The packaging layer is made of a transparent material such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, zirconium oxide, magnesium oxide, zirconium oxide and magnesium fluoride, polymethyl methacrylate, polyethylene oxide, polystyrene, polyvinylpyrrolidone, polycarbonate, polyacrylic acid, epoxy resin, parylene, polysiloxane.

[0097] The packaging layer can be formed by various vacuum plating methods such as thermal evaporation, molecular beam plating or plasma sputtering, atomic layer deposition. Liquid film forming methods such as drop coating, dip coating, spin coating and various printing methods can also be used.

[0098] Example 1

[0099] As Figure 2 shown, is a kind of microcavity organic near-infrared image sensor device structure provided by the embodiment, and the image sensor includes a plurality of arrayed pixel sensing units;The pixel sensing unit is used to detect near-infrared waveband light, especially 900nm target wavelength.The pixel sensing unit includes, from bottom to top, substrate;First electrode 2 arranged on substrate;Second electrode 2 is arranged opposite first electrode 1;Photoelectric conversion layer 3 and optical modulation layer 4 arranged between first electrode 1 and second electrode 2, and electron transport layer 6 and hole transport layer 5, wherein first electrode 1 and second electrode 2 are used as microcavity mirror and form microcavity, and optical modulation layer 4, photoelectric conversion layer 3, electron transport layer 6 and hole transport layer 5 jointly constitute microcavity dielectric layer.

[0100] Wherein, the first electrode 1 is a semi-transparent thin Ag electrode, the thickness is preferably about 5nm, is used as incident side electrode and allows incident light to pass into the cavity;The second electrode 2 is a high-reflection thick Ag electrode, the thickness is preferably about 100nm, is used to provide high reflection to ensure the formation of Fabry-Pérot microcavity;The optical modulation layer 4 is formed by ZnPc:C 60 =1:1 blend, the thickness is preferably about 360nm, is configured to absorb and filter non-target waveband (visible and part of non-target near-infrared) light to suppress background response;The photoelectric conversion layer 3 is formed by PbPc:C 60 =1:1 blend, the thickness is preferably about 100nm, is configured to absorb light in target waveband and generate electrical signal. First electrode 1 and second electrode 2 are used as cavity mirror, and optical modulation layer 4 and photoelectric conversion layer 3 are used as cavity medium, which jointly satisfy the second-order resonance condition 2nL=mλ0, wherein n is the effective refractive index in the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength (900nm in the embodiment). Under the above thickness combination, the total cavity length is preferably about 460nm, so as to form narrow-band resonance enhancement at 900nm.

[0101] As Figure 5 shown, is the spectral external quantum efficiency curve of photoelectric conversion layer 3 in a single device, and the absorption edge extends to the near-infrared region, which can cover the 900nm waveband. The single device refers to a device structure in which only one photoelectric conversion layer 3 is provided, without optical modulation layer or other photoelectric conversion layer.

[0102] As Figure 6 shown, is the spectral external quantum efficiency curve of the device after introducing optical modulation layer 4 and jointly constituting microcavity with photoelectric conversion layer 3, corresponding Figure 3 to the 900nm resonance enhancement curve in the above figure. It can be seen that there is a significant enhancement at 900nm, and there is a secondary resonance enhancement near about 450nm;The response of other non-target wavebands is lower than that before the microcavity is added.

[0103] like Figure 7 The figure shows the absorption spectrum of optical modulation layer 4 in a single-layer structure. It exhibits strong absorption in the visible region, effectively filtering stray light from non-target wavelengths. This represents the absorption spectrum of the optical modulation layer as a photoelectric conversion layer in a standalone device.

[0104] like Figure 8 As shown, the overall external quantum efficiency curve of the device in this embodiment is shown, corresponding to the 900nm resonance enhancement curve in the figure. Narrowband enhancement is achieved in the 900nm band, and the target signal is significantly improved.

[0105] It should be noted that the microcavity formed by the thin Ag first electrode 1 / thick Ag second electrode 2, the optical modulation layer 4, and the photoelectric conversion layer 3 together constitute the main core structure of this invention. Based on this, an electron transport layer (ETL) and a hole transport layer (HTL) can be added between the optical modulation layer 4 and the photoelectric conversion layer 3 and / or on the electrode side, as needed. Preferably, a BCP is used as the electron transport layer.

[0106] BPAPF serves as a hole transport layer and is disposed on the corresponding carrier collection electrode side (e.g., BCP is disposed on the electron collection side and BPAPF is disposed on the hole collection side) to optimize carrier injection, transport and collection, and improve the quantum efficiency, dark current characteristics and long-term stability of the device; the above-mentioned ETL / HTL settings do not change the limitation of the microcavity core structure in this embodiment.

[0107] Example 2

[0108] like Figure 2 The diagram illustrates the device structure of a microcavity organic near-infrared image sensor provided in this embodiment. The image sensor includes multiple pixel sensing units arranged in an array. These pixel sensing units are used to detect near-infrared light, particularly a target wavelength of 940 nm. From bottom to top, each pixel sensing unit comprises: a substrate; a first electrode 2 disposed on the substrate; a second electrode 2 disposed opposite to the first electrode 1; a photoelectric conversion layer 3 and an optical modulation layer 4 disposed between the first electrode 1 and the second electrode 2; and an electron transport layer 6 and a hole transport layer 5. The first electrode 1 and the second electrode 2 together form a microcavity as microcavity mirrors, and the optical modulation layer 4, photoelectric conversion layer 3, electron transport layer 6, and hole transport layer 5 together constitute the microcavity dielectric layer.

[0109] The first electrode 1 is a semi-transparent thin Ag electrode, preferably about 5 nm thick, used as the incident-side electrode and allowing incident light to pass through into the cavity; the second electrode 2 is a highly reflective thick Ag electrode, preferably about 100 nm thick, used to provide high reflectivity to ensure the formation of the Fabry–Pérot microcavity; the optical modulation layer 4 is made of ZnPc:C 60The photoelectric conversion layer 3 is formed by a 1:1 blend, with a preferred thickness of approximately 380 nm, and is configured to absorb and filter non-target wavelengths (visible and part of the non-target near-infrared) light to suppress background response; 60 The materials are blended in a 1:1 ratio and preferably have a thickness of about 100 nm. They are configured to absorb light and generate an electrical signal in the target wavelength band. The first electrode 1 and the second electrode 2 serve as cavity mirrors, and the optical modulation layer 4 and the photoelectric conversion layer 3 serve as cavity media, collectively satisfying the second-order resonance condition 2nL = mλ0, where n is the effective refractive index within the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength (940 nm in this embodiment). With the above thickness combination, the total cavity length is preferably about 480 nm, thereby forming narrowband resonance enhancement at 940 nm.

[0110] like Figure 5 As shown, the external quantum efficiency curve of photoelectric conversion layer 3 in a standalone device is shown. Its absorption edge extends to the near-infrared region and can cover the 940nm band.

[0111] like Figure 6 As shown, the external quantum efficiency curve of the device spectrum after the introduction of the optical modulation layer 4 and the photoelectric conversion layer 3 to form a microcavity is corresponding to the 940nm resonance enhancement curve in the figure. It can be seen that there is a significant enhancement at 940nm, and secondary resonance enhancement exists near about 470nm; the response in other non-target wavelength bands is reduced compared to before the addition of the microcavity.

[0112] like Figure 7 As shown, the absorption spectrum curve of optical modulation layer 4 in a single-layer structure is shown. It has strong absorption in the visible region and can effectively filter stray light in non-target wavelength bands.

[0113] like Figure 8 The figure shows the overall external quantum efficiency curve of the device in this embodiment, corresponding to... Figure 8 The 940nm resonance enhancement curve shows that narrowband enhancement is achieved in the 940nm band, resulting in a significant improvement in the target signal.

[0114] It should be noted that the microcavity formed by the thin Ag first electrode 1 / thick Ag second electrode 2, the optical modulation layer 4, and the photoelectric conversion layer 3 together constitute the main core structure of this invention. Based on this, an electron transport layer (ETL) and a hole transport layer (HTL) can be added between the optical modulation layer 4 and the photoelectric conversion layer 3 and / or on the electrode side, as needed. Preferably, a BCP is used as the electron transport layer.

[0115] BPAPF as a hole transport layer, and disposed on the side of the corresponding carrier collecting electrode (for example, BCP is disposed on the electron collecting side, and BPAPF is disposed on the hole collecting side), so as to optimize the carrier injection, transport and collection, improve the quantum efficiency, dark current characteristics and long-term stability of the device; the arrangement of the above-mentioned ETL / HTL does not change the limitation of the microcavity core structure in the embodiment.

[0116] Embodiment 3

[0117] As shown in Figure 2 , it is a device structure of a microcavity organic near-infrared image sensor provided by the embodiment. The image sensor includes a plurality of arrayed pixel sensing units. The pixel sensing unit is used for detecting near-infrared waveband light, especially 980 nm target wavelength. The pixel sensing unit includes, from bottom to top, a substrate, a first electrode 2 disposed on the substrate, a second electrode 2 disposed opposite to the first electrode 1, a photoelectric conversion layer 3 and an optical modulation layer 4 disposed between the first electrode 1 and the second electrode 2, and an electron transport layer 6 and a hole transport layer 5. The first electrode 1 and the second electrode 2 serve as microcavity mirrors and jointly form a microcavity. The optical modulation layer 4, the photoelectric conversion layer 3, the electron transport layer 6 and the hole transport layer 5 jointly constitute a microcavity medium layer.

[0118] Among them, the first electrode 1 is a semi-transparent thin Ag electrode, the thickness is preferably about 5 nm, which is used as an incident side electrode and allows the incident light to pass into the cavity; the second electrode 2 is a high-reflective thick Ag electrode, the thickness is preferably about 100 nm, which is used to provide high reflection to ensure the formation of the Fabry-Pérot microcavity; the optical modulation layer 4 is formed by ZnPc:C 60 =1:1 blending, the thickness is preferably about 400 nm, which is configured to absorb and filter non-target waveband (visible and part of non-target near-infrared) light to suppress background response; the photoelectric conversion layer 3 is formed by PbPc:C 60 =1:1 blending, the thickness is preferably about 100 nm, which is configured to absorb light in the target waveband and generate an electrical signal. The first electrode 1 and the second electrode 2 serve as cavity mirrors, and the optical modulation layer 4 and the photoelectric conversion layer 3 serve as cavity medium, which jointly satisfy the second-order resonance condition 2nL=mλ0, where n is the effective refractive index in the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength (980 nm in the embodiment). Under the above thickness combination, the total cavity length is preferably about 500 nm, so as to form narrowband resonance enhancement at 980 nm.

[0119] As shown in Figure 5 , it is a spectral external quantum efficiency curve of the photoelectric conversion layer 3 in a single device. The absorption edge extends to the near-infrared region, which can cover the 980 nm waveband.

[0120] As shown in Figure 6As shown, the external quantum efficiency curve of the device spectrum after the introduction of the optical modulation layer 4 and the photoelectric conversion layer 3 to form a microcavity is displayed, corresponding to the 980nm resonance enhancement curve in the figure. It can be seen that a significant enhancement occurs at 980nm, while secondary resonance enhancement exists near approximately 490nm; the response in other non-target wavelength bands is reduced compared to before the addition of the microcavity.

[0121] like Figure 7 As shown, the absorption spectrum curve of optical modulation layer 4 in a single-layer structure is shown. It has strong absorption in the visible region and can effectively filter stray light in non-target wavelength bands.

[0122] like Figure 8 The figure shows the overall external quantum efficiency curve of the device in this embodiment, corresponding to... Figure 8 The 980nm resonance enhancement curve shows that narrowband enhancement is achieved in the 980nm band, resulting in a significant improvement in the target signal.

[0123] Example 4

[0124] like Figure 4 The diagram illustrates the device structure of a microcavity organic near-infrared image sensor provided in this embodiment. The image sensor includes multiple pixel sensing units arranged in an array. These pixel sensing units are used to detect near-infrared light, particularly a target wavelength of 980nm. From bottom to top, each pixel sensing unit comprises: a substrate; a first electrode 2 disposed on the substrate; a second electrode 2 disposed opposite to the first electrode 1; a photoelectric conversion layer 3 and an optical modulation layer 4, an electron transport layer 6 and a hole transport layer 5 disposed between the first electrode 1 and the second electrode 2; and a microlens 8. The first electrode 1 and the second electrode 2 together form a microcavity as microcavity mirrors, and the optical modulation layer 4, photoelectric conversion layer 3, electron transport layer 6, and hole transport layer 5 together constitute a microcavity dielectric layer.

[0125] The first electrode 1 is a semi-transparent thin Ag electrode, preferably about 5 nm thick, used as the incident-side electrode and allowing incident light to pass through into the cavity; the second electrode 2 is a highly reflective thick Ag electrode, preferably about 100 nm thick, used to provide high reflectivity to ensure the formation of the Fabry-Pérot microcavity; the optical modulation layer 4 is made of ZnPc:C 60 The photoelectric conversion layer 3 is formed by a 1:1 blend, with a preferred thickness of approximately 400 nm, and is configured to absorb and filter non-target wavelengths (visible and part of the non-target near-infrared) light to suppress background response; 60The materials are formed by a 1:1 blend, with a preferred thickness of approximately 100 nm, and configured to absorb light and generate an electrical signal in the target wavelength band. The first electrode 1 and the second electrode 2 serve as cavity mirrors, and the optical modulation layer 4 and the photoelectric conversion layer 3 serve as cavity media, collectively satisfying the second-order resonance condition 2nL = mλ0, where n is the effective refractive index within the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength (980 nm in this embodiment). With the above thickness combination, the total cavity length is preferably approximately 500 nm, thereby forming narrowband resonance enhancement at 980 nm.

[0126] like Figure 8 The figure shows the overall external quantum efficiency curve of the device in this embodiment, corresponding to... Figure 8 The 980nm resonance enhancement curve achieves narrowband enhancement in the 980nm band. Compared with the unlensed structure, the target signal peak wavelength position is more accurate and the full width at half maximum (FWHM) is lower, effectively reducing optical interference.

[0127] It should be noted that the microcavity formed by the thin Ag first electrode 1 / thick Ag second electrode 2, the optical modulation layer 4, and the photoelectric conversion layer 3 together constitute the main core structure of this invention. Based on this, an electron transport layer (ETL) and a hole transport layer (HTL) can be added between the optical modulation layer 4 and the photoelectric conversion layer 3 and / or on the electrode side, as needed. Preferably, a BCP is used as the electron transport layer.

[0128] BPAPF serves as a hole transport layer and is disposed on the corresponding carrier collection electrode side (e.g., BCP is disposed on the electron collection side and BPAPF is disposed on the hole collection side) to optimize carrier injection, transport and collection, and improve the quantum efficiency, dark current characteristics and long-term stability of the device; the above-mentioned ETL / HTL settings do not change the limitation of the microcavity core structure in this embodiment.

[0129] Example 5

[0130] like Figure 2 The diagram illustrates the device structure of a tunable near-infrared image sensor provided in this embodiment. The image sensor includes multiple pixel sensing units arranged in an array. These pixel sensing units are used to detect short-wave infrared light, particularly a target wavelength of 1400 nm. From bottom to top, each pixel sensing unit comprises: a substrate; a first electrode 1 disposed on the substrate; a second electrode 2 disposed opposite to the first electrode 1; a photoelectric conversion layer 3 and an optical modulation layer 4 disposed between the first electrode 1 and the second electrode 2; an electron transport layer 6; and a hole transport layer 5. The first electrode 1 and the second electrode 2 together form a microcavity as microcavity mirrors, and the optical modulation layer 4, photoelectric conversion layer 3, electron transport layer 6, and hole transport layer 5 together constitute the microcavity dielectric layer.

[0131] The first electrode 1 is a semi-transparent thin Ag electrode, preferably about 5 nm thick, used as the incident-side electrode and allowing incident light to pass through into the cavity; the second electrode 2 is a highly reflective thick Ag electrode, preferably about 100 nm thick, used to provide high reflectivity to ensure the formation of the Fabry–Pérot microcavity; the optical modulation layer 4 is made of ZnPc:C 60 The optical modulation layer 4 and the photoelectric conversion layer 3 are formed by a 1:1 blend with a thickness of approximately 400 nm. The optical modulation layer 4 is configured to absorb and filter non-target wavelengths (visible and part of the non-target near-infrared) to suppress background response. The photoelectric conversion layer 3 is formed by a blend of a deuterated quinone-terminated N-type small molecule acceptor D1 and a polymer donor PTB7-Th, with a thickness of approximately 120 nm. This layer is configured to absorb light and generate an electrical signal at the target wavelength (1400 nm). The first electrode 1 and the second electrode 2 serve as cavity mirrors, and the optical modulation layer 4 and the photoelectric conversion layer 3 serve as cavity media, jointly satisfying the second-order resonance condition 2nL = mλ0, where n is the effective refractive index within the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength (1400 nm in this embodiment). With the above thickness combination, the total cavity length is preferably approximately 520 nm, thereby forming narrowband resonance enhancement at 1400 nm.

[0132] The chemical formula of the deuterated quinone-terminated N-type small molecule acceptor D1 is as follows:

[0133]

[0134] The preparation method is disclosed in detail in the patent "A short-wave infrared responsive N-type organic molecule with deuterated quinone end caps and the preparation method and application of deuterated quinone end caps", publication number: CN118290445A, publication date: 2024-07-05.

[0135] like Figure 9 As shown, the external quantum efficiency curve of photoelectric conversion layer 3 in a standalone device is shown. Its absorption edge extends to the near-infrared region and can cover the 1400nm band.

[0136] like Figure 10 As shown, the external quantum efficiency curve of the device spectrum after the introduction of the optical modulation layer 4 and the photoelectric conversion layer 3 to form a microcavity is corresponding to the 1400nm resonance enhancement curve in the figure. It can be seen that there is a significant enhancement at 1400nm, and secondary resonance enhancement exists near about 700nm; the response in other non-target wavelength bands is reduced compared to before the addition of the microcavity.

[0137] like Figure 7 As shown, the absorption spectrum curve of optical modulation layer 4 in a single-layer structure is shown. It has strong absorption in the visible region and can effectively filter stray light in non-target wavelength bands.

[0138] like Figure 11The overall spectral external quantum efficiency curve of the device is shown in the figure, corresponding to Figure 8 The resonance enhancement curve in the middle of 1400nm is shown in the figure, and the narrowband enhancement is realized in the 1400nm band, and the target signal is significantly improved.

[0139] It should be noted that the microcavity composed of the thin Ag first electrode 1 / thick Ag second electrode 2, the optical modulation layer 4 and the photoelectric conversion layer 3 jointly constitute the main core structure of the present application. On this basis, an electron transport layer (ETL) and a hole transport layer (HTL) can be added between the optical modulation layer 4 and the photoelectric conversion layer 3 and / or on the electrode side as needed, preferably BCP is used as the electron transport layer and BPAPF is used as the hole transport layer, and is arranged on the side of the corresponding carrier collecting electrode (for example, BCP is arranged on the electron collecting side and BPAPF is arranged on the hole collecting side), so as to optimize the carrier injection, transport and collection, improve the quantum efficiency, dark current characteristics and long-term stability of the device; the above-mentioned arrangement of ETL / HTL does not change the limitation of the core structure of the microcavity in the present embodiment.

[0140] Obviously, the above-mentioned embodiments of the present application are only examples for clearly illustrating the present application, and are not the limitation of the embodiments of the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A tunable near-infrared image sensor for use in biometric identification, the tunable near-infrared image sensor comprising: The tunable near-infrared image sensor comprises a plurality of pixel sensing units forming an image array; The pixel sensing unit comprises: a semi-transparent first electrode; a fully reflective second electrode, which is arranged opposite to the first electrode and forms a microcavity with the first electrode for enhancing the spectral response of a near-infrared target waveband; a photoelectric conversion layer arranged between the first electrode and the second electrode, which absorbs a section of the absorption edge of a waveband as the near-infrared target waveband whose spectral response is enhanced by the microcavity; an optical modulation layer for absorbing and filtering light of wavebands other than the near-infrared target waveband and transmitting carriers, which is arranged between the first electrode and the photoelectric conversion layer; and the cavity length of the microcavity is adjusted by adjusting the thickness of the optical modulation layer to achieve the enhancement of the spectral response of the near-infrared target waveband.

2. The tunable near-infrared image sensor of claim 1, wherein: The near-infrared target waveband refers to a narrow-band waveband with maximum external quantum efficiency at a target wavelength.

3. The tunable near-infrared image sensor of claim 2, wherein: The target wavelength is within 800-3000 nm.

4. The tunable near-infrared image sensor of claim 1, wherein: The transmittance of the first electrode to light of the target waveband is greater than or equal to 70%, and the transmittance of the first electrode to light of the target waveband reflected by the second electrode is less than or equal to 5%.

5. The tunable near-infrared image sensor of claim 4, wherein: The structure of the first electrode comprises a thin-layer metal electrode, a thin-layer metal electrode / metal oxide electrode, a conductive polymer electrode, a carbon-based transparent electrode, a DBR / thin-layer metal electrode, or a DBR / metal oxide electrode.

6. The tunable near-infrared image sensor of claim 1, wherein: The material of the optical modulation layer comprises one or more combinations of an electron donor material that can be used for solution processing, an electron donor material that can be used for thermal evaporation, an electron acceptor material that can be used for solution processing, an electron acceptor material that can be used for thermal evaporation, an organic dye filter material, or an inorganic or high polymer filter material.

7. The tunable near-infrared image sensor of claim 1, wherein: The cavity length of the microcavity is within the range of 200-1000 nm, which satisfies the optical resonance condition 2nL=mλ0, where n is the effective refractive index in the cavity, L is the cavity length, m is an integer, and λ0 is the target wavelength.

8. The tunable near-infrared image sensor of claim 7, wherein: The thickness of the optical modulation layer is 50-300 nm.

9. The tunable near-infrared image sensor of claim 1, wherein: The pixel sensing unit further comprises a first interface functional layer between the optical modulation layer and the photoelectric conversion layer, and / or a second interface functional layer between the second electrode and the photoelectric conversion layer.

10. The tunable near-infrared image sensor according to any one of claims 1 to 9, characterized in that: The top of the pixel sensing unit is further integrated with a microlens for achieving a 120° focusing viewing angle.

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