Organic micro spectrometer based on regulation and control microcavity and self-reference spectrum reconstruction method thereof

Abstract

The invention discloses an organic micro spectrometer based on microcavity regulation and control and a self-reference spectrum reconstruction method thereof. The micro spectrometer comprises a spectrum detection unit array, each spectrum detection unit comprises a regulation and control microcavity, a photoelectric detector used for responding to incident light penetrating through the regulation and control microcavity, and a substrate used for bearing the regulation and control microcavity and the photoelectric detector; the regulation and control micro-cavity comprises a narrow-band micro-cavity for transmitting a narrow-band spectrum and a wide-band micro-cavity for transmitting a wide-band spectrum; the photoelectric detector corresponding to the narrow-band microcavity is defined as a narrow-band detector; the photoelectric detector corresponding to the broadband microcavity is defined as a broadband detector; each regulation and control micro-cavity is of a Fabry-Ru-Perot cavity structure composed of two oppositely arranged semitransparent reflecting layers and a regulation and control layer arranged between the two semitransparent reflecting layers, and different narrow-band micro-cavities or broadband micro-cavities have different regulation and control layer thicknesses; and the thickness of the semitransparent reflecting layer of the narrow-band microcavity is greater than that of the semitransparent reflecting layer of the wide-band microcavity.

Description

Technical Field

[0001] The present invention relates to the technical field of spectrometers, and more specifically, to an organic micro-spectrometer based on a controllable microcavity and a self-reference spectrum reconstruction method thereof. Background Art

[0002] Spectroscopy is an important interdisciplinary subject involving physics and chemistry. It allows analysis of the composition and structure of substances by observing changes in their spectra before and after the interaction of light with them. Due to its advantages of speed, efficiency, cost-effectiveness, and reproducibility, spectral analysis is widely used in a variety of fields, including exhaust gas analysis, crop production monitoring, atmospheric monitoring, food testing, pharmaceutical testing, clinical disease detection, and commodity identification.

[0003] Existing spectrometers typically use only narrowband or broadband detectors for spectral reconstruction. For complex spectra, especially those with sharp and non-negligible narrowband spectra, traditional spectral reconstruction is prone to the following drawbacks: regularization methods (such as GCV) rely on mathematical reductions; they are prone to producing nonphysical solutions (negative spectra, high-frequency oscillations); learning methods require large amounts of training data and have poor generalization. Furthermore, cost reduction remains a challenge for addressing visible-near-infrared spectral detection, especially when no external electric field is required and the spectrometer size is limited. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides an organic micro-spectrometer based on a controllable microcavity and a self-reference spectrum reconstruction method thereof.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] An organic micro-spectrometer based on a controllable micro-cavity, the organic micro-spectrometer comprising an array of spectral detection units;

[0007] Each spectral detection unit includes a control microcavity, a photodetector disposed below the control microcavity, and a substrate for supporting the control microcavity and the photodetector.

[0008] Each spectral detection unit includes a control microcavity, a photodetector for responding to incident light passing through the control microcavity, and a substrate for carrying the control microcavity and the photodetector;

[0009] The control microcavity includes a narrowband microcavity for transmitting a narrowband spectrum and a broadband microcavity for transmitting a broadband spectrum; the photodetector corresponding to the narrowband microcavity is defined as a narrowband detector; the photodetector corresponding to the broadband microcavity is defined as a broadband detector;

[0010] Each control microcavity is a Fabry-Roper cavity structure consisting of two oppositely disposed semitransparent reflective layers and a control layer disposed between the two semitransparent reflective layers. Different narrowband microcavities or broadband microcavities have different control layer thicknesses.

[0011] The thickness of the semi-transparent reflective layer of the narrow-band microcavity is greater than the thickness of the semi-transparent reflective layer of the broadband microcavity.

[0012] Preferably, the regulating layer comprises a dielectric material selected from a 300-1400 nm wavelength band with an extinction coefficient k lower than or equal to 0.12.

[0013] Furthermore, the dielectric material includes one or more of ITO, MoOx, MgF2, SiO2, BPhen, and Alq3.

[0014] Preferably, the control microcavity and the photodetector are respectively located on two opposite sides of the substrate; wherein the substrate is set to be transparent or semi-transparent; and the photodetector is a flip-chip structure.

[0015] Preferably, the control microcavity and the photodetector are both located on the same side of the substrate, and from bottom to top they are substrate, photodetector, and control microcavity; the photodetector is a face-up structure.

[0016] Furthermore, the semi-transparent reflective layer is a semi-transparent metal reflective mirror or a dielectric film reflective layer.

[0017] Preferably, the thickness of the semi-transparent reflective layer of the broadband microcavity is 8-15 nm, the thickness of the semi-transparent reflective layer of the narrowband microcavity is 30-50 nm; and the thickness of the regulating layer is 50-1000 nm.

[0018] A self-reference spectrum reconstruction method for an organic micro-spectrometer based on a controllable microcavity, the self-reference spectrum reconstruction method comprising:

[0019] The regularization algorithm is used to reconstruct all narrow-band detectors in the spectrum detection unit array to obtain the narrow-band spectrum and extract narrowband spectra k self-reference points where λ k represents the wavelength from the reference point, Represents λ k Light intensity at wavelength;

[0020] A regularization algorithm is used to reconstruct all broadband and narrowband detectors in the spectral detection unit array, and the reconstructed spectrum S(λ) is transformed into a function of the full width at half maximum σ of the Gaussian basis function and the corresponding Gaussian basis function weight value α, that is, S(σ,α);

[0021] Using the response matrix and response photocurrent detected by the spectral detection unit array, combined with the reconstructed spectrum S(σ,α), narrowband spectrum The light intensity at the kth self-reference point wavelength is used to construct a mixing cost function;

[0022] Adaptively iteratively optimize the Gaussian basis function full width at half maximum σ and Gaussian basis function weight value α according to the constructed hybrid cost function;

[0023] The iteratively optimized Gaussian basis function full width at half maximum σ and Gaussian basis function weight value α are substituted into the reconstructed spectrum S(λ) to obtain the final reconstructed spectrum.

[0024] Preferably, the narrowband spectrum is extracted k self-reference points Including: Extracting λ by solving extreme value problems k Light intensity at wavelength The specific formula is as follows:

[0025]

[0026] Here, λ represents the wavelength.

[0027] Preferably, a hybrid cost function is constructed, including the following:

[0028]

[0029] in, represents the mixed cost function, I all Represents the response photocurrent corresponding to the detection spectrum detection unit array, R all represents the response matrix of the spectral detection unit array, K represents the total number of self-reference points; β represents the regularization coefficient, To reconstruct the light intensity of the spectrum S(σ,α) at ​​the kth wavelength from the reference point, Reconstructed narrowband spectrum The light intensity at the kth wavelength from the reference point.

[0030] Preferably, the adaptive iterative optimization of the Gaussian function full width at half maximum σ and the Gaussian function weight value α according to the constructed hybrid cost function includes:

[0031]

[0032] Among them, σ i+1 and σ i are the full width at half maximum of the Gaussian basis function at the i+1th iteration and the ith iteration, respectively, with a value range of σ∈[2,200]nm; η is the dynamic learning rate; is the partial derivative of the mixed cost function with respect to σ;

[0033]

[0034] Among them, α i+1 and α i are the Gaussian basis function weights at the i+1th and ith iterations, respectively. It indicates the direction in which the mixed cost function grows fastest. By iteratively adjusting the Gaussian basis function weight value α along the descending direction of the mixed cost function, it gradually approaches the optimal solution.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The organic micro-spectrometer based on a controllable microcavity provided by the present invention includes an array of spectral detection units, each of which includes a controllable microcavity and a photodetector arranged below the controllable microcavity; according to the different designs of the semi-transparent reflective layer of the controllable microcavity, the incident light can be tuned and split into narrowband and broadband, that is, narrowband microcavities and broadband microcavities are integrated in the spectral detection unit array; the photodetector corresponding to the narrowband microcavity is defined as a narrowband detector; the photodetector corresponding to the broadband microcavity is defined as a broadband detector.

[0037] Based on the organic micro-spectrometer of the present invention, a corresponding self-reference spectrum reconstruction method is also provided, which first reconstructs the narrow-band spectrum by using a narrow-band detector. The central wavelength and light intensity of each Gaussian basis function in the matrix are used as reference bases and defined as self-reference points. The spectrum reconstructed by the spectral detection unit array, S(λ), is transformed into a function S(σ,α) about the full width at half maximum (FWHM) of the Gaussian basis function, σ, and the corresponding weight value α. A hybrid cost function is then constructed. During the reconstruction process, the hybrid cost function can be automatically iteratively optimized to find the optimal FWHM and weight value α. Finally, the FWHM and weight value α are substituted into the function S(σ,α) to obtain the final reconstructed spectrum.

[0038] The self-referenced spectral reconstruction method of the present invention can reconstruct complex spectra to be measured with high precision, avoiding the requirement of the existing technology on the number of narrow-band detectors, and solving the problem of cost function instability caused by the differences in the Gaussian basis function itself when using broadband detectors for reconstruction; at the same time, the introduction of organic photodetectors solves the problem of miniaturization and low-cost detection of near-infrared spectra. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention provides a structural schematic diagram of an organic micro-spectrometer based on a controllable microcavity.

[0040] Figure 2The present invention provides a flow chart of a self-reference spectrum reconstruction method of an organic micro-spectrometer based on a controllable microcavity.

[0041] Figure 3 This is a schematic diagram of the normalized light field intensity distribution in a broadband microcavity based on TMM (transfer matrix method) simulation.

[0042] Figure 4 This is a schematic diagram of the normalized light field intensity distribution in a narrowband microcavity based on TMM (transfer matrix method) simulation.

[0043] Figure 5 Schematic diagram of the current density-voltage curve of the organic photodetector in the organic micro-spectrometer.

[0044] Figure 6 is a schematic diagram of the responsivity matrix of the 16 broadband detectors provided.

[0045] Figure 7 Schematic diagram of the response speed of organic photodetectors in organic micro-spectrometers.

[0046] Figure 8 Schematic diagram of the cutoff frequency of the organic photodetector in the organic micro-spectrometer.

[0047] Figure 9 Schematic diagram of the linear dynamic range of organic photodetectors in organic micro-spectrometers.

[0048] Figure 10 This is a schematic diagram of reconstructing the spectrum of the target to be measured using 32 narrow-band detectors.

[0049] Figure 11 It is a diagram of the process of automatically optimizing the cost function to obtain the optimal input parameters as the number of iterations increases.

[0050] Figure 12 It is a schematic diagram of the spectrum of the target to be measured that is finally reconstructed.

[0051] Figure 13 is a diagram showing the minimum deviation when manually adjusting the standard deviation.

[0052] Figure 14 These are several application scenarios of the spectrum reconstruction method described in the present invention.

[0053] Figure 15 This is a comparison chart of the transmittance of a film made of conventional materials and the transmittance reconstructed from a transparent solution placed in a cuvette tested using the organic micro-spectrometer of the present invention, and the test results of a commercial spectrometer.

[0054] In the figure, 100-regulating microcavity, 110-semi-transparent reflective layer, 111-regulating layer, 101-substrate, 102-photodetector, 113-bottom electrode layer, 114-bottom electrode interface layer, 115-photosensitive layer, 116-top electrode interface layer, 117-top electrode layer. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The present invention is described in detail below with reference to the drawings and specific embodiments.

[0056] It should be understood that when used in this specification, the terms "include" and "comprising" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0057] It should also be understood that the terms used in this specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in this specification, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0058] It should be further understood that the term “and / or” used in the description of the present invention refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0059] Example 1

[0060] like Figure 1 As shown, an organic micro-spectrometer based on a controllable microcavity includes an array of spectral detection units; each spectral detection unit includes a controllable microcavity 100, a photodetector 102 for responding to incident light passing through the controllable microcavity 100, and a substrate 101 for supporting the controllable microcavity 100 and the photodetector 102;

[0061] The control microcavity 100 corresponds to the photodetector 102 in a one-to-one manner;

[0062] The control microcavity 100 includes a narrowband microcavity for transmitting a narrowband spectrum and a broadband microcavity for transmitting a broadband spectrum; the photodetector 102 corresponding to the narrowband microcavity is defined as a narrowband detector; the photodetector 102 corresponding to the broadband microcavity is defined as a broadband detector;

[0063] Each control microcavity 100 is a Fabry-Roper cavity structure consisting of two oppositely disposed semitransparent reflective layers 110 and a control layer 111 disposed between the two semitransparent reflective layers 110. Different narrowband microcavities or broadband microcavities have different thicknesses of the control layer 111.

[0064] The thickness of the semi-transparent reflective layer of the narrow-band microcavity is greater than the thickness of the semi-transparent reflective layer of the broadband microcavity.

[0065] In this embodiment, narrowband detectors and broadband detectors are integrated on one substrate 101 , that is, one spectrum detection unit array includes both narrowband detectors and broadband detectors.

[0066] The spectral detection unit array described in this embodiment can be composed of an M×M control microcavity array consisting of M×M control microcavities 100, a photodetector array consisting of M×M photodetectors 102, and a substrate 101 for supporting the control microcavity array and the photodetector array to form an M×M spectral detection unit array. The M×M control microcavity array includes an N×M narrowband microcavity array and a (MN)×M broadband microcavity array. M is a positive integer greater than or equal to 2; N is a positive integer and less than M.

[0067] When performing spectrum reconstruction, the incident light first enters the control microcavity 100 , undergoes tuning and splitting by the control microcavity 100 , and then enters the photodetector 102 .

[0068] In a specific embodiment, the thickness of the semi-transparent reflective layer 110 of the narrowband microcavity is greater than the thickness of the semi-transparent reflective layer 110 of the broadband microcavity, the thickness of the semi-transparent reflective layer 110 of each narrowband microcavity is the same, and the thickness of the semi-transparent reflective layer 110 of each broadband microcavity is the same.

[0069] In this embodiment, the semi-transparent reflective layer 110 is a semi-transparent metal reflective mirror or a dielectric film reflective layer.

[0070] The thickness of the semi-transparent reflective layer 110 of the broadband microcavity is 8-15 nm, and the thickness of the semi-transparent reflective layer 110 of the narrowband microcavity is 20-50 nm.

[0071] The material of the semi-transparent metal reflector includes one of aluminum, silver, gold, magnesium, molybdenum, and titanium; the material of the semi-transparent dielectric film reflector includes but is not limited to SiO2, MgF2, TiO2, TeO2, MoO x The dielectric film reflector is a Bragg reflector structure.

[0072] In a specific embodiment, the regulating layer 111 includes a dielectric material selected from a 300-1400 nm wavelength band with an extinction coefficient k lower than or equal to 0.12.

[0073] The dielectric material includes ITO, MoO x , MgF2, SiO2, BPhen, Alq3 and one or more thereof.

[0074] The thickness of the control layer 111 is 50-1000nm. The thickness of the control layer 111 between different narrowband microcavities should be different, and can change according to a fixed thickness gradient, such as the thickness of the control layer 111 of multiple narrowband microcavities is 50nm, 55nm, 60nm, 65nm, etc., which is gradient-changed according to a fixed thickness of 5nm. It can also not change according to a fixed thickness gradient, such as the thickness of the control layer 111 is 50nm, 55nm, 63nm, 70nm, etc. Similarly, the design of the thickness of the control layer 111 of different broadband microcavities is also similar, and will not be described in detail here. The thickness of the control layer can be adjusted so that the correlation coefficient of the control microcavity is less than or equal to 0.5.

[0075] In addition, the distribution of the control layers 111 with different thicknesses in each control microcavity 100 in the control microcavity array can be regular or irregular. The control microcavities 100 in the control microcavity array can be interconnected or isolated from each other; the control microcavities 100 in the control microcavity array can be arranged in a regular manner or in an irregular manner; the control microcavities 100 in the control microcavity array can have a regular shape (such as square, circular, polygonal, etc.) or an irregular shape; or a combination of several of the above characteristics.

[0076] The present invention provides a plurality of control microcavities 100 with different control layer 111 thicknesses in an organic micro-spectrometer to form transmission combinations with different resonance peak positions, thereby achieving spectrum control through a simple structure while maintaining light intensity.

[0077] The controllable microcavity 100 described in this embodiment can achieve a controllable wavelength range of 300-1400 nm.

[0078] In this embodiment, the preparation method of the semi-transparent reflective layer 110 includes one or more of vacuum thermal evaporation, atomic layer deposition, chemical vapor deposition, electrodeposition, and anodization; the preparation method of the regulating layer 111 includes one or more of vacuum thermal evaporation, electron beam evaporation, molecular beam evaporation or plasma sputtering, atomic layer deposition or liquid film formation followed by reduction conversion, electroplating or electrodeposition.

[0079] In one embodiment, the control microcavity 100 and the photodetector 102 are located on opposite sides of a substrate 101. The substrate 101 is transparent or translucent, and the photodetector 102 is a flip-chip structure. The transparent substrate 101 is made of materials such as glass, quartz, sapphire, and titanium dioxide.

[0080] In another specific embodiment, the control microcavity 100 and the photodetector 102 are located on the same side of the substrate 101, and from bottom to top, they are substrate 101, photodetector 102, and control microcavity 100. The photodetector 102 is a face-up structure. In this case, the substrate 101 can be transparent or opaque, and the materials constituting the substrate 101 include the following: organic materials such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, fluororesin, vinyl chloride, polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene; paper materials such as paper and synthetic paper; composite materials such as materials obtained by coating or laminating metals such as stainless steel, titanium, and aluminum with insulating properties. The materials constituting the substrate 101 can be used alone or in combination of two or more in any combination and ratio.

[0081] The control microcavity 100 described in this embodiment is directly processed on the photodetector 102, which solves the additional interference introduced by the separation of the control microcavity 100 and the photodetector 102 in the traditional solution, shortens the optical path introduced by the control microcavity 100, and effectively reduces the size of the device.

[0082] In a specific embodiment, the photodetector 102 is preferably an organic photodetector. Of course, an organic-inorganic hybrid photodetector, a quantum dot photodetector, or a perovskite photodetector may also be selected.

[0083] In this embodiment, the type of the photodetector 102 is not specifically limited, and its spectral response range only needs to meet 300-1400nm. Considering that organic photodetectors have higher sensitivity, organic photodetectors are preferably used in this embodiment, and the spectral response range of the organic photodetector is: 300-1400nm.

[0084] Taking an organic photodetector as an example, the organic photodetector includes a bottom electrode layer 113, a bottom electrode interface layer 114, a photosensitive layer 115, a top electrode interface layer 116, a top electrode layer 117, and an encapsulation layer. The electrode layer close to the control microcavity 100 is a transparent or semi-transparent electrode layer, and the electrode layer away from the control microcavity 100 is a fully reflective electrode layer.

[0085] When the bottom electrode layer 113 is an anode, the bottom electrode interface layer 114 is a hole transport layer, the top electrode interface layer 116 is an electron transport layer, and the top electrode layer 117 is a cathode.

[0086] When the bottom electrode layer 113 is a cathode, the bottom electrode interface layer 114 is an electron transport layer, the top electrode interface layer 116 is a hole transport layer, and the top electrode layer 117 is an anode.

[0087] The device structure of the organic photodetector array formed by the organic photodetector in this embodiment is as follows: a bottom electrode layer 113 is patterned on one side of the substrate 101;

[0088] a continuous / unpatterned bottom electrode interface layer 114;

[0089] a continuous / unpatterned photosensitive layer 115;

[0090] a continuous / unpatterned top electrode interface layer 116;

[0091] Continuous / unpatterned top electrode layer 117 .

[0092] In this embodiment, the fully reflective electrode layer is selected from one of aluminum, silver, gold, magnesium, molybdenum, and titanium; and the thickness of the fully reflective electrode layer is not less than 80 nm. To form a transparent or semi-transparent electrode, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), zinc oxide (ZnO), or any combination thereof can be used as the material for forming the transparent or semi-transparent electrode.

[0093] In this embodiment, the photosensitive layer 115 includes at least one donor material and at least one acceptor material; wherein the carrier mobility of the electron transport layer is greater than the carrier mobility of the acceptor material in the photosensitive layer 115; and the carrier mobility of the hole transport layer is greater than the carrier mobility of the donor material in the photosensitive layer 115.

[0094] In the photosensitive layer 115, the donor material may be selected from a P-type organic semiconductor based on a specific unit, and the acceptor material may be selected from an N-type organic semiconductor based on a specific unit, including but not limited to the following combinations: PTB7-Th, COTIC-4F and Y6; PTB7-Th, COTIC-4F and Y5; PTB7-Th, COTIC-4F and IT-4F; PTB7-Th, COTIC-4F and ITIC; PTB7: COTIC-4F and Y6; PTB7: COTIC-4F and Y5; PTB7: COTIC-4F and IT-4F; PTB7: COTIC-4F and ITIC; PTB7-Th, IEICO-4F and Y6; PTB7-Th, IEI CO-4F and Y5; PTB7-Th, IEICO-4F and IT-4F; PTB7-Th, IEICO-4F and ITIC; PTB7, IEICO-4F and Y6; PTB7, IEICO-4F and Y5; PTB7, IEICO-4F and IT-4F; PTB7, IEICO-4F and ITIC; PBDB-T, IEICO-4F and Y6; PBDB-T, IEICO-4F and Y5; PBDB-T, IEICO-4F and IT-4F; PBDB-T, IEICO-4F and ITIC; PTB7-Th, COi8DFIC and IT-4F; PTB7-Th, COi8DFIC and ITIC.

[0095] The photosensitive layer 115 is prepared by a solution film forming method or a vacuum thermal evaporation deposition method.

[0096] The bottom electrode interface layer 114 and the top electrode interface layer 116 are prepared independently by one or more methods selected from solution film formation, sol-gel film formation, vacuum thermal evaporation, atomic layer deposition, chemical vapor deposition, electrodeposition, and anodization.

[0097] The bottom electrode layer 113 and the top electrode layer 117 are prepared independently by one or more methods selected from vacuum thermal evaporation, electron beam evaporation, molecular beam evaporation or plasma sputtering, atomic layer deposition or liquid film formation followed by reduction conversion, electroplating or electrodeposition.

[0098] The encapsulation layer is prepared by vacuum thermal evaporation, chemical vapor deposition, atomic layer deposition, plasma sputtering, and liquid film formation.

[0099] Example 2

[0100] Based on the organic micro-spectrometer based on the control micro-cavity provided in Example 1, the present invention provides a self-reference spectrum reconstruction method of the organic micro-spectrometer based on the control micro-cavity, such as Figure 2 As shown, the self-reference spectrum reconstruction method includes the following:

[0101] This method integrates broadband and narrowband detectors, providing complementary and essential functions. The broadband detector provides continuous spectral sampling to capture the entire envelope, while the narrowband microcavity detector generates characteristic self-reference points for fine spectral features. This dual-system approach effectively addresses the inherent complexity of spectral reconstruction, simplifies parameter adjustment, and improves peak localization accuracy. The steps involved are as follows:

[0102] 1. Narrowband self-reference point extraction

[0103] First, the Tikinov regularization algorithm is used to reconstruct all narrow-band detectors in the spectral detection unit array to obtain the narrow-band spectrum and extract narrowband spectra k self-reference points where λ k represents the wavelength from the reference point, Represents λ k The light intensity at the wavelength. Among them, the narrowband spectrum The formula is as follows:

[0104]

[0105] The narrowband spectrum The weight values ​​α of m Gaussian basis functions j Gaussian basis functions φ assigned different weights j (λ) composition; at this time, the narrowband spectrum The initial full width at half maximum of the Gaussian basis function is σ init ; α is solved by regularization algorithm:

[0106]

[0107] In the reconstruction, the response photocurrent I of the narrowband detector is used nro , R nro ∈R 32×m represents the narrowband response matrix (32 channels × m Gaussian basis functions), and L is the Laplace smoothing operator.

[0108] The extracted narrowband spectrum k self-reference points Includes: Based on narrowband spectroscopy Extracting λ by solving extreme value problems k Light intensity at wavelength The specific formula is as follows:

[0109]

[0110] Where λ represents the narrowband spectrum wavelength.

[0111] 2. Constructing a hybrid cost function (also called a cost function)

[0112] Subsequently, the Tikinov regularization algorithm is used to reconstruct all broadband and narrowband detectors in the spectral detection unit array, and the reconstructed spectrum S(λ) is transformed into a function of the full width at half maximum σ of the Gaussian basis function and the corresponding Gaussian basis function weight value α, that is, S(σ,α). The formula for reconstructing the spectrum S(σ,α) is as follows:

[0113]

[0114] Where n represents the number of Gaussian basis functions. The full width at half maximum of the Gaussian basis function S(σ,α) is σ i ; α i It is also solved by regularization algorithm, which is the same as formula (3):

[0115] Using the response matrix and response photocurrent detected by the spectral detection unit array, combined with the reconstructed spectrum S(σ,α), narrowband spectrum The light intensity at the kth self-reference point wavelength is used to construct a mixing cost function, specifically including:

[0116] After preprocessing, the response matrix R of the spectrum detection unit array (including narrowband and broadband detectors) is detected. all , real-time detection of the response photocurrent I corresponding to the spectrum detection unit array all , construct the mixed cost function These may include:

[0117]

[0118] In formula (7), represents the mixed cost function, I all Represents the response photocurrent corresponding to the detection spectrum detection unit array, R all represents the response matrix of the spectrum detection unit array, K represents the total number of self-reference points; is the light intensity of the spectrum to be reconstructed S(σ,α) at ​​the kth wavelength from the reference point, Reconstructed narrowband spectrum The light intensity at the kth wavelength from the reference point. β represents the regularization coefficient, β∈[0.1,1.0], with a preferred value of 0.5. The full width at half maximum of the Gaussian basis function σ∈[2,200]nm.

[0119] 3. Adaptive Optimization

[0120] According to the constructed hybrid cost function, the Gaussian basis function full width at half maximum σ and the Gaussian basis function weight value α are adaptively iteratively optimized; specifically, the following are included:

[0121]

[0122] Among them, σ i+1 and σ i are the full width at half maximum of the Gaussian basis function after the update (i.e., iteration i+1) and at iteration i, respectively. The value range is: σ∈[2,200]nm. η is the dynamic learning rate (shared with α for the update, η is initialized to 0.1 and adaptively adjusted based on the convergence status). is the partial derivative of the mixed cost function with respect to σ. When the spectral features are sharp Narrow σ; conversely, widen σ. Ultimately, the goal of adaptive resolution optimization is achieved.

[0123]

[0124] Among them, the dynamic learning rate η is initialized to 0.1 and adaptively adjusted according to the convergence situation. i+1 and α i are the Gaussian basis function weight values ​​at the i+1th and ith iterations respectively. It indicates the direction in which the hybrid cost function increases fastest. By iteratively adjusting the Gaussian basis function weight value α along the descending direction of the hybrid cost function, it gradually approaches the optimal solution. The iteration stops, usually within 10 times.

[0125] The iteratively optimized Gaussian basis function full width at half maximum σ and Gaussian basis function weight value α are substituted into the reconstructed spectrum S(λ) to obtain the final reconstructed spectrum.

[0126] The present invention reconstructs a narrowband spectrum by using a narrowband detector The central wavelength and light intensity of each Gaussian basis function in the matrix are used as reference bases and defined as self-reference points. The spectrum reconstructed by the spectral detection unit array, S(λ), is transformed into a function S(σ,α) about the Gaussian basis function's full width at half maximum, σ, and the corresponding Gaussian basis function's weight value, α. A hybrid cost function is then constructed. During the reconstruction process, the hybrid cost function can be automatically iteratively optimized to find the optimal Gaussian basis function's full width at half maximum, σ, and Gaussian basis function's weight value, α. Finally, the optimized Gaussian basis function's full width at half maximum, σ, and Gaussian basis function's weight value, α, are substituted into the function S(σ,α) to obtain the final reconstructed spectrum.

[0127] The self-referenced spectral reconstruction method of the present invention can reconstruct complex spectra to be measured with high precision, avoiding the requirement of the existing technology on the number of narrow-band detectors, and solving the problem of cost function instability caused by the differences in the Gaussian basis function itself when using broadband detectors for reconstruction; at the same time, the introduction of organic photodetectors solves the problem of miniaturization and low-cost detection of near-infrared spectra.

[0128] It should be noted that the regulated microcavities of different thicknesses in the present invention have both high transmittance and differentiated response performance in the spectral detection unit array, so the photodetection chip can effectively distinguish the enhanced absorption band in the incident light. The low absorption of light by the reflective electrode combined with the high-performance photodetector at the back end improves the detection accuracy and expands the detection range. In order to reconstruct the spectrum in different scenarios, two working modes are developed based on algorithm design. The micro-spectrometer can realize substance concentration detection, sorting of different materials and characteristic spectrum reconstruction in passive scenarios. At the same time, an integrated module is designed, which successfully binds the spectral detection chip and the adapter circuit board with an adapter interface with the back-end integrated readout circuit, realizing the preparation of an organic micro-spectrometer with broad application prospects.

[0129] Example 3

[0130] Figure 1 An organic micro-spectrometer based on a controllable microcavity is demonstrated, including an array of spectral detection units; each spectral detection unit includes a controllable microcavity 100, a substrate 101, and a photodetector 102 in sequence.

[0131] The spectrum detection unit array is composed of 64 spectrum detection units, that is, the control microcavity array is composed of 64 control microcavities, including 32 narrowband microcavities and 32 broadband microcavities, that is, there are 32 narrowband detectors and 32 broadband detectors. The spectrum detection unit corresponding to the broadband microcavity includes from left to right: 13nm first semi-transparent reflection layer (110) / microcavity control layer with uniform thickness variation: 65-440nm (111) / 13nm second semi-transparent reflection layer (112) / 1mm glass substrate (101) / 150nm ITO bottom electrode (113) / 30nm zinc oxide bottom electrode interface layer (114) / 220nm photosensitive layer (PTB7-Th:COTIC-4F:Y6=1:1.45:0.05) (115) / 10nm molybdenum oxide top electrode interface layer 116 (116) / 100nm Ag total reflection electrode layer (117). In the spectrum detection unit corresponding to the narrowband microcavity, except that the thickness of the semi-transparent reflective layer in the narrowband microcavity is 30 nm, the rest of the configuration is the same as that of the spectrum detection unit corresponding to the broadband microcavity.

[0132] Specifically, this embodiment further provides a method for preparing an organic micro-spectrometer based on a controllable microcavity, comprising the following steps:

[0133] S1. A glass substrate with a 150 nm thick ITO layer was placed on a washing rack and ultrasonically cleaned using isopropyl alcohol.

[0134] S2. Continue to spin-coat a zinc oxide bottom electrode interface layer with a thickness of 30 nm;

[0135] S3. Spin-coat the photosensitive material and adjust the spin-coating speed until a photosensitive layer with a thickness of 220 Å (PTB7-Th:COTIC-4F:Y6=1:1.45:0.05) is formed;

[0136] S4. Anneal on a heating plate at 90-100°C for 10-15 min.

[0137] S5. Use a laser to remove the remaining film above the pins, exposing the metal pins and electrode contacts;

[0138] S6. Depositing a 10 nm molybdenum oxide top electrode interface layer through a patterned mask;

[0139] S7. Depositing a 100 nm Ag fully reflective electrode layer through a patterned mask;

[0140] S8. Clean the glass substrate backplane with isopropyl alcohol;

[0141] S9. Depositing a 13 nm first semi-transparent electrode layer (broadband microcavity) and a 30 nm first semi-transparent electrode layer (narrowband microcavity) through a patterned mask;

[0142] S10. Depositing or sputtering a microcavity control layer with a uniform thickness of 65-440 nm through a patterned mask;

[0143] S11. A second semi-transparent electrode layer (broadband microcavity) of 13 nm and a second semi-transparent electrode layer (narrowband microcavity) of 30 nm were deposited through a patterned mask;

[0144] S12. Encapsulating the spectrum detection unit array under argon atmosphere;

[0145] S13. Use spring pins and a fixed housing to bind the prepared spectral detection unit array chip to an adapter board containing an interface compatible with the back-end integrated circuit to form a micro-spectrometer detection module.

[0146] Figure 3 and Figure 4 The organic micro-spectrometer described in this embodiment is used to simulate the normalized light field intensity distribution in the broadband microcavity and narrowband microcavity based on the TMM (transfer matrix method). Figure 3 、 Figure 4 It can be seen that there are multiple resonance peaks distributed in different bands.

[0147] Figure 5 The dark current of the organic photodetector in this embodiment is demonstrated. The characterization and measurement of the organic photodetector array can be performed using a semiconductor parameter analyzer and a source meter to test the current density-voltage curves in the dark and under a 1050 nm light source.

[0148] Figure 6The responsivity matrix of 16 broadband detectors is shown, all of which are calculated from the external quantum efficiency. The specific calculation method is conventional in the field and will not be explained here. The external quantum efficiency spectrum is performed using a halogen lamp (SOFN Instruments Co. Ltd, 7IPT250B) incident light, a low-noise current preamplifier (Stanford Research Systems, SR570), a phase-locked amplifier (Stanford Research Systems, SR830) and a calibrated silicon and indium gallium arsenide (InGaAs) photodetector. In order to distinguish the differences between different pixels, an offset is added to each curve with a step size of 0.01A / W.

[0149] Figure 7 and Figure 8 The response speed and -3dB bandwidth of broadband and narrowband detectors are shown. For frequency-dependent measurements, an LED (light-emitting diode) modulated by a function generator (Tektronix AFG1062) was used as the signal source, applying square waves of varying frequencies. The photocurrent response of the organic photodetector array was recorded using a digital storage oscilloscope (Tektronix MDO3052).

[0150] Figure 9 The linear dynamic range of the organic photodetector array in this embodiment is demonstrated. A narrowband LED with a central wavelength of 1050 nm, driven by a Keithley 2450 Source Meter, was used as the light source. The light intensity was modulated by adjusting the output power, and the corresponding light power was measured using an optical power meter (Newport 1919-R) equipped with a silicon detector (Newport 818-UV / DB). The photocurrent of the organic photodetector array under different light intensities was recorded using a semiconductor analyzer (Platform Design Automation, Inc. FS380 Pro).

[0151] Figure 10 The self-reference spectrum reconstruction method described in Example 2 is used to obtain a narrowband spectrum of the target to be measured. The full width at half maximum in the Gaussian basis function is optimized based on the mixed cost function, and the full width at half maximum in the Gaussian basis function is obtained, such as Figure 11 As shown. The final reconstructed spectrum of the target to be measured is obtained, and the result of the final reconstructed spectrum is output, as shown Figure 12 shown. Figure 11 The σ and Figure 13 When manually adjusting the parameters, the minimum deviation σ (25nm) remains consistent. Figure 14 These are several application scenarios of the spectrum reconstruction method described in Example 2.

[0152] This embodiment demonstrates the material analysis application effect of the organic micro-spectrometer of the present invention. Figure 15 The demonstration focuses on the design and functional verification of the material analysis module of the portable micro-spectrometer. Figure 15 As shown, this embodiment uses a collimated halogen lamp as a light source to detect and analyze thin film materials and colorless transparent liquids respectively. For thin film material testing, the thin film is prepared by spin coating a solution on a quartz plate and then drying it. A micro-spectrometer is used to measure and reconstruct the transmission spectrum of light before and after passing through the thin film / quartz plate, and the transmission spectrum is compared with the transmission spectrum measured by a commercial spectrometer. In order to achieve the sorting and identification of colorless transparent liquids, the near-infrared transmittance of the colorless transparent liquid is tested. The liquid sample is placed in a cuvette, and a long-wave pass filter is added in front of the micro-spectrometer. The transmission spectrum of light before and after passing through the liquid / cuvette is measured and reconstructed using the micro-spectrometer, and the near-infrared transmittance spectrum is calculated based on this and compared with the transmission spectrum measured by the commercial spectrometer. Figure 15 (a) Schematic diagram showing the experimental principle of measuring the transmittance of solution-processed materials spin-coated on a substrate using a micro-spectrometer and a commercial spectrometer. Figure 15 (b) is the transmittance of common polymer material PCE-10 at different thicknesses. Figure 15 (c) Comparison of the transmittance of the small molecule receptor material IEICO-4F when spin-coated onto a substrate. The high accuracy and stability of the reconstruction results demonstrate that the micro-spectrometer is capable of identifying visible-shortwave infrared thin film materials. Figure 15 (d) Schematic diagram of the experimental principles for testing transmittance using a micro-spectrometer and a commercial spectrometer when the volume ratios of water, ethanol, and water and ethanol are equal, respectively. Figure 15 (e) is the transmittance curve of these colorless and transparent solutions. Since the reconstruction results can be restored to the characteristic peak of water (near 940nm), which is close to the test curve of the micro-spectrometer, it can be considered that the micro-spectrometer has the ability to detect colorless and transparent solution materials. Finally, Figure 15 (f) shows a real picture of the organic micro-spectrometer, where the volume of the micro-spectrometer is 2.5 cm × 2.5 cm × 1 cm, and the area of ​​the organic spectrum detection chip is 2.25 cm 2 Its small size, light weight, stable and static structure, and switching circuit compatible with back-end integrated circuits further illustrate its miniaturized design and portability.

[0153] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention, and are not intended to limit the embodiments of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. An organic micro-spectrometer based on a controllable microcavity, characterized by: The organic micro-spectrometer includes a spectrum detection unit array; Each spectral detection unit includes a control microcavity, a photodetector for responding to incident light passing through the control microcavity, and a substrate for carrying the control microcavity and the photodetector; The control microcavity includes a narrowband microcavity for transmitting a narrowband spectrum and a broadband microcavity for transmitting a broadband spectrum; the photodetector corresponding to the narrowband microcavity is defined as a narrowband detector; the photodetector corresponding to the broadband microcavity is defined as a broadband detector; Each control microcavity is a Fabry-Roper cavity structure consisting of two oppositely disposed semitransparent reflective layers and a control layer disposed between the two semitransparent reflective layers. Different narrowband microcavities or broadband microcavities have different control layer thicknesses. The thickness of the semi-transparent reflective layer of the narrow-band microcavity is greater than the thickness of the semi-transparent reflective layer of the broadband microcavity.

2. The organic micro-spectrometer based on a controllable microcavity according to claim 1, characterized in that: The regulating layer includes a dielectric material selected from a 300-1400 nm wavelength band with an extinction coefficient k lower than or equal to 0.

12.

3. The organic micro-spectrometer based on a controllable microcavity according to claim 2, characterized in that: The dielectric material includes ITO, MoO x , MgF2, SiO2, BPhen, Alq3 and one or more thereof.

4. The organic micro-spectrometer based on a controllable microcavity according to claim 1, characterized in that: The control microcavity and the photodetector are respectively located on two opposite sides of the substrate; The substrate is transparent or semi-transparent; and the photodetector is a flip-chip structure.

5. The organic micro-spectrometer based on a controllable microcavity according to claim 1, characterized in that: The control microcavity and the photodetector are both located on the same side of the substrate, and from bottom to top they are the substrate, the photodetector, and the control microcavity; the photodetector is a positive-mounted structure.

6. The organic micro-spectrometer based on a controllable microcavity according to claim 1, characterized in that: The semi-transparent reflective layer is a semi-transparent metal reflective mirror or a dielectric film reflective layer.

7. The organic micro-spectrometer based on a controllable microcavity according to claim 6, characterized in that: The thickness of the semi-transparent reflective layer of the broadband microcavity is 8-15 nm, the thickness of the semi-transparent reflective layer of the narrowband microcavity is 20-50 nm; the thickness of the regulating layer is 50-1000 nm.

8. A self-referenced spectrum reconstruction method for an organic micro-spectrometer based on a controllable micro-cavity, based on the organic micro-spectrometer based on a controllable micro-cavity according to any one of claims 1 to 7, characterized in that: The self-reference spectrum reconstruction method includes the following steps: The regularization algorithm is used to reconstruct all narrow-band detectors in the spectrum detection unit array to obtain the narrow-band spectrum and extract narrowband spectra k self-reference points where λ k represents the wavelength from the reference point, Represents λ k Light intensity at wavelength; A regularization algorithm is used to reconstruct all broadband and narrowband detectors in the spectral detection unit array, and the reconstructed spectrum S(λ) is transformed into a function of the full width at half maximum σ of the Gaussian basis function and the corresponding Gaussian basis function weight value α, that is, S(σ,α); Using the response matrix and response photocurrent detected by the spectrum detection unit array, combined with the reconstructed spectrum i(σ,α), narrowband spectrum The light intensity at the kth self-reference point wavelength is used to construct a mixing cost function; Adaptively iteratively optimize the Gaussian basis function full width at half maximum σ and Gaussian basis function weight value α according to the constructed hybrid cost function; The iteratively optimized Gaussian basis function full width at half maximum σ and Gaussian basis function weight value α are substituted into the reconstructed spectrum S(λ) to obtain the final reconstructed spectrum.

9. The self-referenced spectrum reconstruction method of the organic micro-spectrometer based on the controllable microcavity according to claim 8, characterized in that: The extracted narrowband spectrum k self-reference points Including: Extracting λ by solving extreme value problems k Light intensity at wavelength The specific formula is as follows: Here, λ represents the wavelength.

10. The self-referenced spectrum reconstruction method of the organic micro-spectrometer based on the controllable microcavity according to claim 8, characterized in that: Constructing the mixed cost function includes the following: in, represents the mixed cost function, I all Represents the response photocurrent corresponding to the detection spectrum detection unit array, R all represents the response matrix of the spectral detection unit array, K represents the total number of self-reference points; β represents the regularization coefficient, is the light intensity of the spectrum to be reconstructed S(σ,α) at ​​the kth wavelength from the reference point, Reconstructed narrowband spectrum The light intensity at the kth wavelength from the reference point.

11. The self-referenced spectrum reconstruction method of the organic micro-spectrometer based on the controllable microcavity according to claim 8, characterized in that: According to the constructed hybrid cost function, the Gaussian basis function half-height full width σ and the Gaussian basis function weight value α are adaptively iteratively optimized, including: Among them, σ i+1 and σ i are the full width at half maximum of the Gaussian basis function at the i+1th iteration and the ith iteration, σ∈[2,200]nm; η is the dynamic learning rate; is the partial derivative of the mixed cost function with respect to σ; Among them, α i+1 and α i are the Gaussian basis function weights at the i+1th and ith iterations, respectively. It indicates the direction in which the mixed cost function grows fastest. By iteratively adjusting the Gaussian basis function weight value α along the descending direction of the mixed cost function, it gradually approaches the optimal solution.

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