camera device

Abstract

The camera of the present disclosure includes a semiconductor substrate, a plurality of pixel electrodes above the semiconductor substrate and electrically connected to the semiconductor substrate, a counter electrode above the plurality of pixel electrodes, a first photoelectric conversion layer between the plurality of pixel electrodes and the counter electrode, and at least one first light shielding body in the first photoelectric conversion layer or above the first photoelectric conversion layer. The first photoelectric conversion layer includes semiconductor quantum dots that absorb light in a first wavelength range and a covering material that covers the semiconductor quantum dots, absorbs light in a second wavelength range, and emits fluorescent light in a third wavelength range. The at least one first light shielding body absorbs or reflects light in at least a portion of the wavelengths in the second wavelength range.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an imaging device. BACKGROUND

[0002] Research on an imaging device obtained by stacking a photoelectric conversion section composed of a semiconductor quantum dot on a semiconductor substrate is actively being conducted. The semiconductor quantum dot has a characteristic that if the crystal size thereof is changed, the energy gap changes by quantum size effect, and thus by controlling the material and the crystal size of the semiconductor quantum dot used in the photoelectric conversion section, an imaging device having sensitivity to a desired wavelength region can be realized.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: International Publication No. 2019 / 150971

[0006] NON-PATENT DOCUMENTS

[0007] Non-Patent Document 1: Mengxia Liu et. al., “Lattice anchoring stabilizes solution-processed semiconductors”, Nature, 2019, Vol. 570, p. 96-101 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] An imaging device in which noise is reduced is desired. Thus, in the present disclosure, an imaging device in which noise is reduced is provided.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] An imaging device of one aspect of the present disclosure includes: a semiconductor substrate; a plurality of pixel electrodes located above the semiconductor substrate and electrically connected to the semiconductor substrate; a counter electrode located above the plurality of pixel electrodes; a first photoelectric conversion layer located between the plurality of pixel electrodes and the counter electrode; and at least one first light shielding body located in the first photoelectric conversion layer or above the first photoelectric conversion layer. The first photoelectric conversion layer includes a semiconductor quantum dot having a property of absorbing light in a first wavelength range and a covering material covering the semiconductor quantum dot and having a property of absorbing light in a second wavelength range and emitting fluorescence in a third wavelength range. The at least one first light shielding body absorbs or reflects light in at least a part of the second wavelength range.

[0012] Furthermore, one aspect of the imaging device disclosed herein includes: a semiconductor substrate; a plurality of pixel electrodes located above the semiconductor substrate and electrically connected to the semiconductor substrate; a counter electrode located above the plurality of pixel electrodes; a first photoelectric conversion layer located between the plurality of pixel electrodes and the counter electrode; and at least one second light-shielding body located within the first photoelectric conversion layer or between the first photoelectric conversion layer and the plurality of pixel electrodes. The first photoelectric conversion layer comprises semiconductor quantum dots and a covering material. The semiconductor quantum dots have the characteristic of absorbing light in a first wavelength range, and the covering material covers the semiconductor quantum dots and has the characteristic of absorbing light in a second wavelength range and emitting fluorescence in a third wavelength range. The at least one second light-shielding body absorbs or reflects at least a portion of the wavelengths in the third wavelength range.

[0013] Invention Effects

[0014] It can provide camera devices with reduced noise. Attached Figure Description

[0015] Figure 1A This is a schematic diagram illustrating an example of the morphology of a semiconductor quantum dot.

[0016] Figure 1B This is a schematic diagram illustrating an example of the morphology of a semiconductor quantum dot.

[0017] Figure 2 This is a graph showing the absorption and fluorescence spectra of the P3HT thin film.

[0018] Figure 3A This is a graph showing the absorption and fluorescence spectra of the CsPbBr2I thin film.

[0019] Figure 3B This is a graph showing the absorption and fluorescence spectra of the CsSnI3 thin film.

[0020] Figure 3C This is a graph showing the absorption and fluorescence spectra of the CH3NH3SnI3 thin film.

[0021] Figure 4 This is a circuit diagram illustrating an exemplary circuit configuration of the camera device according to Embodiment 1.

[0022] Figure 5 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device according to Embodiment 1.

[0023] Figure 6 This is a diagram showing an example of the absorption spectrum of a semiconductor quantum dot.

[0024] Figure 7This is a schematic diagram illustrating an example of the absorption spectrum of a semiconductor quantum dot containing multiple semiconductor quantum dots.

[0025] Figure 8 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device in Embodiment 2.

[0026] Figure 9 This indicates C60, C70, BT-CIC, and CO. i The absorption spectrum of the 8DFIC thin film.

[0027] Figure 10 This is a graph showing the simulation results of light transmittance for C70 layers of different thicknesses.

[0028] Figure 11 This indicates CO with different thicknesses. i A graph showing the simulation results of the light transmittance of the hybrid layer of 8DFIC and C70.

[0029] Figure 12 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device in Embodiment 3.

[0030] Figure 13 This is a graph showing the absorption spectrum of a mixed film of SnNcCl2 and C70.

[0031] Figure 14 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device in Embodiment 4.

[0032] Figure 15 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device in Embodiment 5.

[0033] Figure 16 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device in Embodiment 6.

[0034] Figure 17 This is a schematic diagram showing the cross-sectional structure of multiple pixels of the camera device in Embodiment 7. Detailed Implementation

[0035] (For the purpose of gaining insight into one of the solutions disclosed herein)

[0036] Semiconductor quantum dots can also be used directly as photoelectric conversion materials. However, freshly synthesized semiconductor quantum dots are often covered by ligands or other materials to improve their dispersion stability in solvents and suppress secondary particle formation. Figure 1A and Figure 1B This is a schematic diagram illustrating an example of the morphology of a semiconductor quantum dot. Regarding freshly synthesized semiconductor quantum dots, for example... Figure 1AThe surface of the semiconductor quantum dot 200A with a two-layer structure of core 210 and shell 220 as shown, or Figure 1B The semiconductor quantum dot 200B with a single-layer structure, such as the core 210 shown, has surface-modifying groups adsorbed or bonded to its surface, called ligands 230. Typically, the ligands 230 covering the freshly synthesized semiconductor quantum dots are mostly molecules with long-chain alkyl groups, such as oleic acid or oleylamine. Molecules with long-chain alkyl groups can hinder the conductivity between semiconductor quantum dots. Therefore, by exchanging ligands between molecules with long-chain alkyl groups and shorter organic molecules, low-molecular-weight molecules with π-conjugation systems, or halogen atoms, the conductivity between semiconductor quantum dots can be improved.

[0037] When using ligand-exchanged semiconductor quantum dots as a photoelectric conversion layer, a dispersion of semiconductor quantum dots is coated onto electrodes or similar surfaces. However, when only a dispersion of semiconductor quantum dots is coated onto electrodes or similar surfaces, the dried semiconductor quantum dot film is brittle and prone to cracking, making homogeneous film formation difficult. In this case, for example, by incorporating a material softer than semiconductor quantum dots, such as a semiconductor polymer or perovskite material, into the semiconductor quantum dots to form a semiconductor quantum dot film, the film quality of the dried film is improved.

[0038] Patent Document 1 discloses a photoelectric conversion layer comprising semiconductor quantum dots. To improve the conductivity between the semiconductor quantum dots, ligands modifying the surface of the semiconductor quantum dots are replaced with conductive compounds having a π-conjugated system, such as benzene or thiophene compounds; and the semiconductor quantum dots are mixed with semiconductor polymers such as thiophene polymers or 3-hexylthiophene (P3HT). However, when ligand exchange is performed using conductive compounds having a π-conjugated system, it is difficult to completely remove the remaining conductive compounds having a π-conjugated system from the surface of the unmodified semiconductor quantum dots. Furthermore, when mixed with a semiconductor polymer, the mixed semiconductor polymer may not completely contact and cover the surface of the semiconductor quantum dots. Therefore, thin films composed of ligand-exchanged semiconductor quantum dots, thin films formed by mixing semiconductor polymers and semiconductor quantum dots, or thin films of mixtures obtained by combining them, typically also contain ligands and semiconductor polymers that do not contact the semiconductor quantum dots.

[0039] Furthermore, Non-Patent Document 1 discloses a solar cell using a structure in which semiconductor quantum dots (lead sulfide (PbS) quantum dots) are embedded within a perovskite material film by spin-coating a dispersion formed by mixing a lead sulfide (PbS) quantum dot precursor with a lattice constant matching the lattice constant of the perovskite material atoms. In this case, at the interface between the perovskite material layer and the semiconductor quantum dots, the lattice spacing of the lead atoms matches the lattice spacing of the perovskite material layer, thus forming an interface that suppresses structural defects, resulting in excellent solar cell characteristics. In such a hybrid film using perovskite material as the substrate and embedding semiconductor quantum dots within it, a substrate material that does not contact the semiconductor quantum dots is also included.

[0040] In the process of advancing research on imaging devices incorporating a photoelectric conversion layer containing semiconductor quantum dots, the inventors discovered the following issues. Ligand materials suitable for improving the conductivity between semiconductor quantum dots, and matrix materials such as semiconductor polymers and perovskite materials—that is, covering materials for semiconductor quantum dots—mostly absorb light and emit fluorescence. The wavelength of the absorbed light varies depending on the type of covering material, but it ranges from ultraviolet to near-infrared light. Furthermore, the wavelength of the fluorescence emitted by the covering material varies depending on the type of material, but it is mostly a wavelength tens to about 100 nm longer than the wavelength of the absorbed light.

[0041] Figure 2 This is a graph showing the absorption and fluorescence spectra of a P3HT thin film, a semiconductor polymer that serves as an example of a matrix material. Figure 2 In the diagram, the absorption spectrum of the P3HT thin film is represented by a dotted line, and the fluorescence spectrum is represented by a solid line. Furthermore, in... Figure 2 In the diagrams, the horizontal axis of both the absorption and fluorescence spectra represents wavelength, the vertical axis of the absorption spectrum represents absorbance, and the vertical axis of the fluorescence spectrum represents fluorescence intensity. These will be used in the following description. Figures 3A-3C The same applies to China.

[0042] like Figure 2 As shown, a P3HT thin film, which is a semiconductor polymer, absorbs light in the wavelength range of about 400 nm to about 650 nm and emits fluorescence in the wavelength range of about 550 nm to about 750 nm.

[0043] Figure 3A This is a graph showing the absorption and fluorescence spectra of CsPbBr2I thin films, another example of perovskite materials used as matrix materials. (Example:) Figure 3A As shown, the CsPbBr2I film absorbs light in the wavelength range of about 340 nm to about 600 nm and emits fluorescence in the wavelength range of about 560 nm to about 620 nm.

[0044] also, Figure 3B This is a graph showing the absorption and fluorescence spectra of CsSnI3 thin films, another example of a perovskite material used as a matrix material. (See figure.) Figure 3B As shown, the CsSnI3 film absorbs light in the wavelength range of about 400 nm to about 950 nm and emits fluorescence in the wavelength range of about 850 nm to about 1000 nm.

[0045] also, Figure 3C This is a graph showing the absorption and fluorescence spectra of a CH3NH3SnI3 thin film, another example of a matrix material. (See figure.) Figure 3C As shown, the CH3NH3SnI3 thin film absorbs light in the wavelength range below about 1050 nm and emits fluorescence in the wavelength range of about 800 nm to about 1100 nm.

[0046] In a camera device, light is irradiated onto a photoelectric conversion layer, causing semiconductor quantum dots to absorb photons and convert them into electrical charges, which are then extracted to the outside as signal charges. When the photoelectric conversion layer includes a substrate material such as a semiconductor polymer or perovskite material, the substrate material within the photoelectric conversion layer also absorbs photons and emits fluorescence isotropically. Therefore, the fluorescence emitted by the substrate material within the photoelectric conversion layer is emitted in a direction different from the direction of the light irradiating the camera device. Since the fluorescence emitted from this substrate material isotropically emitted from within the photoelectric conversion layer, in a camera device having a photoelectric conversion layer above a semiconductor substrate, it is possible to irradiate the semiconductor layer constituting the charge accumulation region and control circuitry of the camera device. For example, in the case of single-crystal silicon, which is most commonly used as the material for charge accumulation regions and control circuitry, light in the wavelength range of approximately 200 nm to approximately 1100 nm is absorbed. Therefore, when using a silicon-containing semiconductor substrate, if fluorescence in this wavelength range is irradiated, the irradiated fluorescence may be absorbed in the charge accumulation region and control circuitry of the semiconductor substrate. Figure 2 , Figure 3A , Figure 3B and Figure 3C As shown, the wavelengths of fluorescence emitted by typical semiconductor polymers and perovskite materials are essentially contained within the wavelength range absorbed by the semiconductor layer. Furthermore, the same phenomenon can occur when using π-conjugated compounds such as benzene or thiophene compounds as ligand materials. While the ligand materials for these π-conjugated compounds vary depending on the type of material, most of them absorb wavelengths in the ultraviolet-visible region and emit fluorescence with wavelengths tens to approximately 100 nm longer than those wavelengths.

[0047] Furthermore, for example, in the case of single-crystal gallium arsenide, which is often used as a material in charge storage regions and control circuits, it absorbs light in the wavelength range of about 200 nm to about 800 nm. Therefore, when a semiconductor substrate containing gallium arsenide is used, if it is irradiated with fluorescence in this wavelength range, the irradiated fluorescence may also be absorbed in the charge storage region and control circuit of the semiconductor substrate.

[0048] If photons of fluorescence are absorbed in a charge accumulation region, a charge is generated in that region. The charge generated by absorbing such fluorescence is indistinguishable from the charge generated by the absorption of externally incident photons by semiconductor quantum dots within the photoelectric conversion layer. A particularly problematic situation arises when photons of fluorescence generated by the ligand or matrix material of the π-conjugated compound in the photoelectric conversion layer of one pixel are absorbed in the charge accumulation region of another pixel. In this case, signal charges are generated at locations other than where the light was originally incident, causing image blurring, color mixing, and noise. This problem arises because the ligand or matrix material of the π-conjugated compound within the photoelectric conversion layer also emits light in a direction different from the direction of the light incident on the imaging device. Furthermore, if the fluorescence emitted by the ligand or matrix material of the π-conjugated compound within the photoelectric conversion layer is absorbed by the control circuit, it can also cause circuit malfunctions and increased noise.

[0049] As described above, the inventors have discovered that in the case of an imaging device having a photoelectric conversion layer on a semiconductor substrate using semiconductor quantum dots, which are mixed with ligand materials or matrix materials of π-conjugated compounds, as photoelectric conversion materials, the fluorescence emitted by the ligand materials or matrix materials of the π-conjugated compounds becomes a cause of increased noise in the imaging device. Therefore, this disclosure provides an imaging device that can reduce noise even in imaging devices having a photoelectric conversion layer on a semiconductor substrate using semiconductor quantum dots, which are mixed with a covering material of semiconductor quantum dots such as ligand materials or matrix materials of π-conjugated compounds, as photoelectric conversion materials.

[0050] A summary of one embodiment of this disclosure is as follows.

[0051] One aspect of the imaging device disclosed herein includes: a semiconductor substrate; a plurality of pixel electrodes located above and electrically connected to the semiconductor substrate; a counter electrode located above the plurality of pixel electrodes; a first photoelectric conversion layer located between the plurality of pixel electrodes and the counter electrode; and at least one first light-shielding body located within or above the first photoelectric conversion layer. The first photoelectric conversion layer comprises semiconductor quantum dots and a covering material. The semiconductor quantum dots have the property of absorbing light in a first wavelength range, and the covering material covers the semiconductor quantum dots and has the property of absorbing light in a second wavelength range and emitting fluorescence in a third wavelength range. The at least one first light-shielding body absorbs or reflects at least a portion of the light in the second wavelength range.

[0052] Therefore, the first light-shielding body is located inside or above the first photoelectric conversion layer. Here, "the first light-shielding body is located above the first photoelectric conversion layer" means that the first light-shielding body is located above the first surface of the first photoelectric conversion layer, which is closer to the counter electrode than the multiple pixel electrodes, in either the first surface or the second surface opposite to the first surface. Furthermore, "the first light-shielding body is located above the first photoelectric conversion layer" can also be described as the first light-shielding body being located in the region opposite to the semiconductor substrate where the first photoelectric conversion layer is sandwiched, i.e., the region on the side where light is incident on the first photoelectric conversion layer. Therefore, before light in the second wavelength range reaches the cover material, the first light-shielding body absorbs or reflects the light in the second wavelength range. Thus, the absorption of the second wavelength range light by the cover material can be reduced, resulting in a reduction in fluorescence emitted by the cover material. Therefore, noise generated by the absorption of fluorescence emitted by the cover material by charge accumulation regions of the semiconductor substrate, including impurity regions, or control circuits can be suppressed. In other words, the first light-shielding body reduces the amount of second wavelength range light reaching the cover material, which is a cause of noise in the imaging device. Therefore, it is possible to achieve a camera device with reduced noise.

[0053] In addition, for example, the aforementioned at least one first light-shielding body may also include an optical filter located above the aforementioned counter electrode, which absorbs or reflects light of at least a portion of the aforementioned wavelengths in the aforementioned second wavelength range.

[0054] Therefore, the optical filter is located above the first photoelectric conversion layer, that is, closer to the side where light is incident on the imaging device than the first photoelectric conversion layer. Thus, before reaching the first photoelectric conversion layer, the optical filter absorbs or reflects at least a portion of the light in the second wavelength range. Consequently, the amount of light in the second wavelength range reaching the covering material can be effectively reduced, thus lowering the noise of the imaging device.

[0055] In addition, for example, the aforementioned at least one first light-shielding body may also include a first charge transport layer located between the aforementioned first photoelectric conversion layer and the aforementioned counter electrode, and absorb the aforementioned light of at least a portion of the aforementioned wavelengths in the aforementioned second wavelength range.

[0056] Therefore, the first charge transport layer is located above the first photoelectric conversion layer, i.e., closer to the side of the imaging device where light is incident on the image. Thus, before reaching the first photoelectric conversion layer, the first charge transport layer absorbs at least a portion of the light in the second wavelength range. Consequently, the amount of light in the second wavelength range reaching the covering material can be effectively reduced, thus lowering the noise of the imaging device.

[0057] In addition, for example, the aforementioned at least one first light-shielding body may also include a second photoelectric conversion layer located between the aforementioned first photoelectric conversion layer and the aforementioned counter electrode, and absorb the light of at least a portion of the aforementioned wavelengths in the aforementioned second wavelength range.

[0058] Therefore, the second photoelectric conversion layer is located above the first photoelectric conversion layer, i.e., closer to the side where light is incident on the imaging device than the first photoelectric conversion layer. Thus, the second photoelectric conversion layer absorbs at least a portion of the light in the second wavelength range before it reaches the first photoelectric conversion layer. Consequently, the amount of light in the second wavelength range reaching the covering material can be effectively reduced, thus lowering the noise of the imaging device.

[0059] In addition, for example, the aforementioned at least one first light-shielding body may also include a first material different from the aforementioned semiconductor quantum dot that absorbs light of at least a portion of the aforementioned wavelengths in the aforementioned second wavelength range, the aforementioned first material being located within the aforementioned first photoelectric conversion layer.

[0060] Therefore, by having the first material located within the first photoelectric conversion layer, the first material absorbs at least a portion of the light in the second wavelength range incident on the first photoelectric conversion layer. Consequently, the amount of light in the second wavelength range reaching the covering material can be reduced, thus lowering the noise of the imaging device.

[0061] Furthermore, for example, the first light-shielding body described above can also allow light of at least a portion of the wavelengths in the first wavelength range to pass through.

[0062] Therefore, since light in the first wavelength range can easily reach the semiconductor quantum dot, the reduction in photoelectric conversion function in the first photoelectric conversion layer can be suppressed.

[0063] In addition, at least one of the aforementioned first light-shielding bodies can also absorb or reflect light with wavelengths below 1050 nm.

[0064] As a result, light in the near-infrared to visible wavelength range is absorbed or reflected by the first light-shielding body, and light in the near-infrared to visible wavelength range becomes less likely to be absorbed by the covering material.

[0065] In addition, for example, at least one second light-shielding body may be provided, which is located within the first photoelectric conversion layer or between the first photoelectric conversion layer and the plurality of pixel electrodes, and absorbs or reflects light of at least a portion of the wavelengths of the third wavelength range.

[0066] Therefore, the second light-shielding body is located within the first photoelectric conversion layer, or between the first photoelectric conversion layer and the multiple pixel electrodes. Thus, even when the cover material emits fluorescence in the third wavelength range, the second light-shielding body absorbs or reflects the light in the third wavelength range. Consequently, the amount of light in the third wavelength range reaching the charge accumulation regions of the semiconductor substrate, including impurity regions, or the control circuitry can be reduced. That is, the first light-shielding body reduces the amount of light in the second wavelength range reaching the cover material, and the second light-shielding body reduces the amount of light in the third wavelength range reaching the charge accumulation regions of the semiconductor substrate, including impurity regions, or the control circuitry, which contributes to noise in the imaging device. Therefore, an imaging device with further reduced noise can be realized.

[0067] Furthermore, one aspect of the imaging device disclosed herein includes: a semiconductor substrate; a plurality of pixel electrodes located above the semiconductor substrate and electrically connected to the semiconductor substrate; a counter electrode located above the plurality of pixel electrodes; a first photoelectric conversion layer located between the plurality of pixel electrodes and the counter electrode; and at least one second light-shielding body located within the first photoelectric conversion layer or between the first photoelectric conversion layer and the plurality of pixel electrodes. The first photoelectric conversion layer comprises semiconductor quantum dots and a covering material. The semiconductor quantum dots have the characteristic of absorbing light in a first wavelength range, and the covering material covers the semiconductor quantum dots and has the characteristic of absorbing light in a second wavelength range and emitting fluorescence in a third wavelength range. The at least one second light-shielding body absorbs or reflects at least a portion of the wavelengths in the third wavelength range.

[0068] Therefore, the second light-shielding body is located within the first photoelectric conversion layer, or between the first photoelectric conversion layer and the multiple pixel electrodes. Thus, even when the covering material emits fluorescence in the third wavelength range, the second light-shielding body absorbs or reflects light in the third wavelength range. Consequently, light in the third wavelength range reaching the charge accumulation regions of the semiconductor substrate, including impurity regions, or the control circuitry can be reduced. In other words, the second light-shielding body reduces light in the third wavelength range reaching the charge accumulation regions of the semiconductor substrate, including impurity regions, or the control circuitry, which contributes to noise in the imaging device. Therefore, an imaging device with reduced noise can be realized.

[0069] Furthermore, for example, the aforementioned at least one second light-shielding body may also contain a second material that absorbs light of at least a portion of the aforementioned wavelengths in the aforementioned third wavelength range. Unlike the aforementioned semiconductor quantum dot, the aforementioned second material is located within the aforementioned first photoelectric conversion layer.

[0070] Therefore, by having the second material located within the first photoelectric conversion layer, the second material absorbs at least a portion of the fluorescence emitted by the covering material in the third wavelength range. Consequently, light in the third wavelength range reaching the charge accumulation region of the semiconductor substrate, including impurity regions, or the control circuit can be reduced, thus lowering the noise of the imaging device.

[0071] In addition, for example, the aforementioned at least one second light-shielding body may also include a second charge transport layer, which is located between the aforementioned first photoelectric conversion layer and the aforementioned plurality of pixel electrodes, and absorbs the aforementioned light of at least a portion of the aforementioned wavelengths in the aforementioned third wavelength range.

[0072] Therefore, the second charge transport layer is located on the side of the multiple pixel electrodes of the first photoelectric conversion layer, that is, closer to the semiconductor substrate than the first photoelectric conversion layer. Thus, before reaching the semiconductor substrate, the second charge transport layer absorbs at least a portion of the light in the third wavelength range. Consequently, the amount of light in the third wavelength range reaching the charge accumulation region of the semiconductor substrate, including impurity regions, or the control circuit, can be reduced, thus lowering the noise of the imaging device.

[0073] Furthermore, for example, the aforementioned covering material may also include at least one selected from the group consisting of a matrix material and a ligand material having π-conjugation. The aforementioned matrix material may also include at least one selected from the group consisting of semiconductor polymers, semiconductor copolymers, semiconductor oligomers, low-molecular-weight semiconductors, perovskite materials, and double perovskite materials.

[0074] This improves the conductivity within the first photoelectric conversion layer. Consequently, the efficiency of signal charge extraction from the first photoelectric conversion layer is enhanced.

[0075] Furthermore, for example, the first photoelectric conversion layer described above may also contain a third material that functions as an acceptor relative to the semiconductor quantum dot described above.

[0076] Therefore, as electrons move from the hole-electron pairs generated by the semiconductor quantum dots to the acceptor material, the recombination of the hole-electron pairs can be suppressed, thus improving the photoelectric conversion efficiency of the first photoelectric conversion layer.

[0077] Furthermore, for example, the first photoelectric conversion layer may also include a third material that functions as an acceptor relative to the semiconductor quantum dot and the first material.

[0078] Therefore, as electrons move from the electron-hole pairs generated by the semiconductor quantum dots to the acceptor material, the recombination of electron-hole pairs can be suppressed, thus improving the photoelectric conversion efficiency of the first photoelectric conversion layer. Furthermore, as electrons move from the electron-hole pairs generated by light absorption through the first material to the acceptor material, energy generation caused by the recombination of electron-hole pairs can be suppressed.

[0079] Furthermore, for example, the first photoelectric conversion layer may also include a third material that functions as an acceptor relative to the semiconductor quantum dot and the second material.

[0080] Therefore, as electrons move from the electron-hole pairs generated by the semiconductor quantum dots to the acceptor material, the recombination of electron-hole pairs can be suppressed, thus improving the photoelectric conversion efficiency of the first photoelectric conversion layer. Furthermore, as electrons move from the electron-hole pairs generated by light absorption through the second material to the acceptor material, energy generation caused by the recombination of electron-hole pairs can be suppressed.

[0081] In addition, for example, the semiconductor substrate described above may also contain silicon.

[0082] Even with a camera device that uses a silicon semiconductor substrate containing silicon that easily absorbs the fluorescence emitted by the covering material, the noise of the camera device is reduced.

[0083] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0084] It should be noted that the embodiments described below are all general or specific examples. The numerical values, shapes, materials, constituent elements, the arrangement and connection of constituent elements, steps, and the order of steps shown in the following embodiments are examples and are not intended to limit this disclosure. Furthermore, in the constituent elements of the following embodiments, constituent elements not described in the independent claims are described as arbitrary constituent elements.

[0085] Furthermore, in this specification, elements necessary for the operation of the imaging device or effective for improving its characteristics but not useful for the description of this disclosure have been omitted. Also, the accompanying drawings are merely conceptual diagrams, and scales, shapes, etc., are not taken into consideration. Therefore, for example, scales, etc., may not be consistent across different drawings. Furthermore, in each drawing, substantially identical components are labeled with the same symbol, and repetitive descriptions are omitted or simplified.

[0086] Furthermore, in this specification, terms such as "equal" indicating the relationship between elements, and terms such as "square" or "circle" indicating the shape of elements, as well as numerical ranges, are not expressions that only have a strict meaning, but also include substantially equivalent ranges, such as differences of a few percent.

[0087] Furthermore, in this specification, the terms "above" and "below" do not refer to the absolute spatial direction of upward (vertical above) and downward (vertical below), but are used as terms defined based on the stacking order in a layered composition and through relative positional relationships. Additionally, the terms "above" and "below" apply not only to situations where two constituent elements are arranged with a gap between them and other constituent elements exist between them, but also to situations where two constituent elements are arranged closely together and in contact with each other.

[0088] (Implementation Method 1)

[0089] [Circuit configuration of the camera device]

[0090] First, regarding the circuit configuration of the camera device in this embodiment, using Figure 4 Please provide an explanation.

[0091] Figure 4 This is a circuit diagram illustrating an exemplary circuit configuration of the camera device according to this embodiment. Figure 4 The camera device 100 shown has a pixel array PA comprising a plurality of pixels 10 arranged in two dimensions. Figure 4 The illustration shows an example of pixels 10 arranged in a 2x2 matrix. The number and arrangement of pixels 10 in the imaging device 100 are not limited to... Figure 4 The example shown is an example of this. For instance, the camera device 100 could also be a linear sensor consisting of multiple pixels 10 arranged in a column.

[0092] Each pixel 10 has a photoelectric conversion unit 13 and a signal detection circuit 14. The photoelectric conversion unit 13 receives incident light and generates a signal. The photoelectric conversion unit 13 does not necessarily need to be a separate element in each pixel 10, or it can be a part of the photoelectric conversion unit 13 spanning multiple pixels 10. The signal detection circuit 14 is a circuit that detects the signal generated by the photoelectric conversion unit 13. In this example, the signal detection circuit 14 includes a signal detection transistor 24 and an addressing transistor 26. The signal detection transistor 24 and the addressing transistor 26 are typically field-effect transistors (FETs). Here, an N-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is shown as the signal detection transistor 24 and the addressing transistor 26. Each transistor, including the signal detection transistor 24, the addressing transistor 26, and the reset transistor 28 (described later), has a control terminal, an input terminal, and an output terminal. The control terminal is, for example, the gate. The input terminal is one of the drain and the source, for example, the drain. The output terminal is either the drain or the source, for example, the source.

[0093] like Figure 4 As schematically shown, the control terminal of the signal detection transistor 24 is electrically connected to the photoelectric conversion unit 13. The signal charge generated by the photoelectric conversion unit 13 is stored in the charge storage node 41 between the gate of the signal detection transistor 24 and the photoelectric conversion unit 13. Here, the signal charge is a hole or an electron. The charge storage node is an example of a charge storage unit and is also referred to as a "floating diffusion node". Furthermore, in this specification, the charge storage node is also referred to as a charge storage region. The detailed structure of the photoelectric conversion unit 13 will be described below.

[0094] Each pixel 10's photoelectric conversion unit 13 is further connected to a bias control line 42 and a predetermined voltage is applied to it. Figure 4 In the example configuration, the bias control line 42 is connected to the voltage supply circuit 32.

[0095] Each pixel 10 is connected to the power line 40 that supplies the power supply voltage VDD. For example... Figure 4 As shown, the input terminal of the signal detection transistor 24 is connected to the power supply line 40. The power supply line 40 functions as a source follower, thereby amplifying and outputting the signal generated by the photoelectric conversion unit 13.

[0096] An input terminal of an addressing transistor 26 is connected to the output terminal of the signal detection transistor 24. The output terminal of the addressing transistor 26 is connected to one of the plurality of vertical signal lines 47 arranged in each column of the pixel array PA. The control terminal of the addressing transistor 26 is connected to the addressing control line 46. By controlling the potential of the addressing control line 46, the output power of the signal detection transistor 24 can be selectively read out to the corresponding vertical signal line 47.

[0097] In the illustrated example, addressing control line 46 is connected to vertical scanning circuit 36. Vertical scanning circuit is also called "row scanning circuit". Vertical scanning circuit 36 ​​selects multiple pixels 10 arranged in each row on a row-by-row basis by applying a specified voltage to addressing control line 46. This performs the reading of signals from the selected pixel 10 and the reset of charge accumulation node 41.

[0098] Vertical signal line 47 is the main signal line that transmits pixel signals from pixel array PA to peripheral circuits. Column signal processing circuits 37 are connected to vertical signal line 47. Column signal processing circuit 37 is also called a "row signal accumulation circuit." Column signal processing circuit 37 performs noise suppression signal processing, such as correlated double sampling, and analog-to-digital conversion. As shown, column signal processing circuits 37 are arranged corresponding to each column of pixels 10 in pixel array PA. Horizontal signal readout circuits 38 are connected to these column signal processing circuits 37. Horizontal signal readout circuits 38 are also called "column scanning circuits." Horizontal signal readout circuits 38 sequentially read signals from multiple column signal processing circuits 37 to the horizontal common signal line 49.

[0099] exist Figure 4 In the illustrated configuration, pixel 10 has a reset transistor 28. The reset transistor 28 is, for example, a field-effect transistor, similar to the signal detection transistor 24 and the addressing transistor 26. Unless otherwise specified, the following description uses an N-channel MOSFET as the reset transistor 28. As shown, the reset transistor 28 is connected between the reset voltage line 44, which supplies the reset voltage Vr, and the charge accumulation node 41. The control terminal of the reset transistor 28 is connected to the reset control line 48. By controlling the potential of the reset control line 48, the potential of the charge accumulation node 41 can be reset to the reset voltage Vr. In this example, the reset control line 48 is connected to the vertical scan circuit 36. Therefore, by applying a predetermined voltage to the reset control line 48 through the vertical scan circuit 36, the multiple pixels 10 arranged in each row can be reset row by row.

[0100] In this example, the reset voltage line 44, which supplies the reset voltage Vr to the reset transistor 28, is connected to the reset voltage source 34. The reset voltage source is also referred to as the "reset voltage supply circuit." The reset voltage source 34 is not limited to a specific power supply circuit, as long as it has the configuration to supply a predetermined reset voltage Vr to the reset voltage line 44 when the imaging device 100 is in operation. Similar to the voltage supply circuit 32 described above, it is not limited to a specific power supply circuit. The voltage supply circuit 32 and the reset voltage source 34 can each be part of a single voltage supply circuit or independent, separate voltage supply circuits. It should be noted that one or both of the voltage supply circuit 32 and the reset voltage source 34 can also be part of the vertical scanning circuit 36. Alternatively, the control voltage from the voltage supply circuit 32 and / or the reset voltage Vr from the reset voltage source 34 can also be supplied to each pixel 10 via the vertical scanning circuit 36.

[0101] The reset voltage Vr can also be the power supply voltage VDD of the signal detection circuit 14. In this case, the voltage supply circuit that supplies the power supply voltage to each pixel 10 can be used. Figure 4(Not shown in the diagram) and the reset voltage source 34 are shared. Furthermore, since the power supply line 40 and the reset voltage line 44 can be shared, the wiring in the pixel array PA can be simplified. However, by setting the reset voltage Vr to a voltage different from the power supply voltage VDD of the signal detection circuit 14, more flexible control of the camera device 100 can be achieved.

[0102] [Pixel's Device Structure]

[0103] Next, for the cross-sectional structure of the plurality of pixels 10 of the camera device 100 in this embodiment, using Figure 5 Please provide an explanation.

[0104] The imaging device 100 includes a first light-shielding element. The first light-shielding element absorbs or reflects light of at least a portion of the wavelength range of the second wavelength range. The first light-shielding element is located within or above the first photoelectric conversion layer 15. Various examples of the first light-shielding element will be shown in detail below.

[0105] Figure 5 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10 of the camera device 100 in this embodiment. Figure 5 The multiple pixels 10 shown all have the same structure, but the multiple pixels 10 may also have some different structures. The following description focuses on one pixel 10 among the multiple pixels 10. Each pixel 10 of the imaging device 100 includes: a semiconductor substrate 20; multiple pixel electrodes 11 located above the semiconductor substrate 20 and electrically connected to the semiconductor substrate 20; a counter electrode 12 located above the multiple pixel electrodes 11; a first photoelectric conversion layer 15 located between the multiple pixel electrodes 11 and the counter electrode 12; and an optical filter 16 located above the counter electrode 12. Light enters the pixel 10 from above the semiconductor substrate 20. In this embodiment, the first light-shielding body includes the optical filter 16.

[0106] exist Figure 5 In the illustrated configuration, the signal detection transistor 24, addressing transistor 26, and reset transistor 28 described above are formed on the semiconductor substrate 20. The semiconductor substrate 20 is not limited to a substrate that is entirely semiconductor. The semiconductor substrate 20 may also be an insulating substrate, such as one on the surface where a semiconductor layer is formed on the side containing the photosensitive area. For example, a silicon-containing semiconductor substrate may be used as the semiconductor substrate 20. Here, an example using a P-type silicon (Si) substrate as the semiconductor substrate 20 will be described. The semiconductor substrate 20 is not limited to a silicon-containing semiconductor substrate; for example, it may be another semiconductor substrate, such as a gallium arsenide-containing semiconductor substrate.

[0107] The semiconductor substrate 20 has impurity regions 26s, 24s, 24d, 28d, and 28s, and a component separation region 20t for electrical separation between each pixel 10. Here, the impurity regions 26s, 24s, 24d, 28d, and 28s are N-type regions. Furthermore, the component separation region 20t is disposed between the impurity regions 24d and 28d. The component separation region 20t is formed, for example, by ion implantation of a acceptor under specified implantation conditions.

[0108] Impurity regions 26s, 24s, 24d, 28d, and 28s are, for example, impurity diffusion layers formed within the semiconductor substrate 20. Figure 5 As schematically shown, the signal detection transistor 24 includes impurity regions 24s and 24d, and a gate electrode 24g. The gate electrode 24g is formed using a conductive material. The conductive material can be, for example, polysilicon that has been made conductive by doping with impurities, but it can also be a metallic material. The impurity region 24s functions as, for example, the source region of the signal detection transistor 24. The impurity region 24d functions as, for example, the drain region of the signal detection transistor 24. A channel region of the signal detection transistor 24 is formed between the impurity regions 24s and 24d.

[0109] Similarly, the addressing transistor 26 includes impurity regions 26s and 24s, and a gate electrode 26g. The gate electrode 26g is formed using a conductive material. The conductive material can be, for example, polysilicon, which is made conductive by doping with impurities, but it can also be a metallic material. The gate electrode 26g and... Figure 5 Addressing control line 46 (not shown) is connected. In this example, signal detection transistor 24 and addressing transistor 26 are electrically connected to each other through a common impurity region 24s. The impurity region 24s functions as, for example, the drain region of addressing transistor 26. The impurity region 26s functions as, for example, the source region of addressing transistor 26. The impurity region 26s and Figure 5 The vertical signal line 47 (not shown) is connected. It should be noted that the impurity region 24s may not be shared by the signal detection transistor 24 and the addressing transistor 26. Specifically, the source region of the signal detection transistor 24 and the drain region of the addressing transistor 26 may be separated within the semiconductor substrate 20 and electrically connected via a wiring layer disposed within the interlayer insulating layer 50.

[0110] The reset transistor 28 includes impurity regions 28d and 28s, and a gate electrode 28g. The gate electrode 28g is formed, for example, using a conductive material. The conductive material is, for example, polycrystalline silicon, which acquires conductivity through impurity doping, but it can also be a metallic material. The gate electrode 28g and... Figure 5The reset control line 48 (not shown) is connected. The impurity region 28s functions as, for example, the source region of the reset transistor 28. The impurity region 28s is connected to... Figure 5 The reset voltage line 44, not shown in the diagram, is connected. The impurity region 28d functions as, for example, the drain region of the reset transistor 28.

[0111] An interlayer insulating layer 50 is disposed on the semiconductor substrate 20 in such a manner as covering signal detection transistor 24, addressing transistor 26, and reset transistor 28. The interlayer insulating layer 50 is formed, for example, of an insulating material such as silicon dioxide. As shown, a wiring layer 56 is disposed within the interlayer insulating layer 50. The wiring layer 56 is typically formed of a metal such as copper. The wiring layer 56 may, for example, include signal lines or power lines such as the aforementioned vertical signal line 47 in a portion thereof. The number of insulating layers in the interlayer insulating layer 50 and the number of layers contained in the wiring layer 56 disposed within the interlayer insulating layer 50 can be arbitrarily set and are not limited to a specific number. Figure 5 The example shown.

[0112] Furthermore, in the interlayer insulation layer 50, such as Figure 5 As shown, a plug 52, wiring 53, contact plug 54, and contact plug 55 are provided. Wiring 53 may also be part of wiring layer 56. Plug 52, wiring 53, contact plug 54, and contact plug 55 are each formed using a conductive material. For example, plug 52 and wiring 53 are formed of a metal such as copper. Contact plugs 54 and 55 are formed, for example, of polycrystalline silicon, which is made conductive by doping with impurities. It should be noted that plug 52, wiring 53, contact plug 54, and contact plug 55 may be formed using the same material or different materials.

[0113] The plug 52, wiring 53, and contact plug 54 constitute at least a portion of the charge accumulation node 41 between the signal detection transistor 24 and the photoelectric conversion unit 13. Figure 5 In the illustrated configuration, the gate electrode 24g, plug 52, wiring 53, contact plugs 54 and 55 of the signal detection transistor 24, and one of the source and drain regions of the reset transistor 28, namely the impurity region 28d, function as a charge storage region for accumulating signal charge collected by the pixel electrode 11 of the photoelectric conversion unit 13.

[0114] Specifically, the pixel electrode 11 of the photoelectric conversion unit 13 is connected to the gate electrode 24g of the signal detection transistor 24 via a plug 52, wiring 53, and contact plug 54. In other words, the gate of the signal detection transistor 24 is electrically connected to the pixel electrode 11. Furthermore, the pixel electrode 11 is also connected to the impurity region 28d via a plug 52, wiring 53, and contact plug 55.

[0115] By capturing signal charge through pixel electrode 11, a voltage corresponding to the amount of signal charge stored in the charge storage region is applied to the gate of signal detection transistor 24. Signal detection transistor 24 amplifies this voltage. The voltage amplified by signal detection transistor 24 is selectively read out as a signal voltage via addressing transistor 26.

[0116] The aforementioned photoelectric conversion unit 13 is disposed on the interlayer insulating layer 50. When viewed from above, a plurality of pixels 10 arranged in two dimensions form a photosensitive area. This photosensitive area is also referred to as a pixel area. The distance between two adjacent pixels 10, i.e., the pixel pitch, can be, for example, approximately 2 μm.

[0117] [Structure of the photoelectric conversion unit]

[0118] The specific structure of the photoelectric conversion unit 13 will be described below.

[0119] like Figure 5 As shown, the photoelectric conversion unit 13 includes a plurality of pixel electrodes 11, a counter electrode 12, and a first photoelectric conversion layer 15 disposed between the plurality of pixel electrodes 11 and the counter electrode 12. Furthermore, an optical filter 16 is provided on the counter electrode 12 of the photoelectric conversion unit 13. In this embodiment, the optical filter 16, the counter electrode 12, the first photoelectric conversion layer 15, and the plurality of pixel electrodes 11 are arranged sequentially from the light incident side relative to the imaging device 100. That is, the optical filter 16 is disposed closer to the counter electrode 12 than the first photoelectric conversion layer 15, in other words, on the light incident side.

[0120] The photoelectric conversion unit 13 may further include other elements such as an electron blocking layer and a hole blocking layer.

[0121] exist Figure 4 In the example shown, the counter electrode 12, the first photoelectric conversion layer 15, and the optical filter 16 are formed across multiple pixels 10. Pixel electrodes 11 are disposed in each pixel 10. The pixel electrodes 11 are electrically separated from the pixel electrodes 11 of other adjacent pixels 10 by being spatially separated. It should be noted that at least one of the counter electrode 12, the first photoelectric conversion layer 15, and the optical filter 16 may also be disposed separately in each pixel 10.

[0122] The pixel electrode 11 is an electrode used to read out the signal charge generated by the photoelectric conversion unit 13. At least one pixel electrode 11 exists in each pixel 10. The pixel electrode 11 is electrically connected to the gate electrode 24g of the signal detection transistor 24 and the impurity region 28d.

[0123] The pixel electrode 11 is formed using a conductive material. The conductive material is, for example, a metal such as aluminum or copper, a metal nitride, or polycrystalline silicon that has been made conductive by doping with impurities.

[0124] The counter electrode 12 is, for example, a transparent electrode formed of a transparent conductive material. The counter electrode 12 is disposed on the light-incident side of the first photoelectric conversion layer 15. Therefore, light passing through the counter electrode 12 is incident into the first photoelectric conversion layer 15. It should be noted that the light detected by the imaging device 100 is not limited to the wavelength range of visible light. For example, the imaging device 100 can also detect infrared light or ultraviolet light. Here, the wavelength range of visible light is, for example, 380 nm to 780 nm.

[0125] It should be noted that "transparent" in this specification means that at least a portion of the wavelength range of light to be detected is allowed to pass through, not that the light must pass through the entire wavelength range of visible light. For convenience, electromagnetic waves including infrared and ultraviolet light are collectively referred to as "light" in this specification.

[0126] The counter electrode 12 is formed using, for example, a transparent conductive oxide (TCO), such as ITO, IZO, AZO, FTO, SnO2, TiO2, or ZnO. A [missing information - likely a component or material] is connected to the counter electrode 12. Figure 4 The voltage supply circuit 32 shown is used to adjust the voltage applied to the counter electrode 12 by the voltage supply circuit 32. This allows the potential difference between the counter electrode 12 and the pixel electrode 11 to be set and maintained at the desired potential difference.

[0127] For reference Figure 6 As explained, the counter electrode 12 is connected to the bias control line 42, which is connected to the voltage supply circuit 32. Furthermore, the counter electrode 12 is formed across multiple pixels 10. Therefore, via the bias control line 42, a desired control voltage can be applied simultaneously between the multiple pixels 10 by the voltage supply circuit 32. It should be noted that, as long as a desired control voltage can be applied by the voltage supply circuit 32, the counter electrode 12 can also be separately provided in each pixel 10.

[0128] By controlling the potential of the counter electrode 12 relative to the pixel electrode 11 through the voltage supply circuit 32, either holes or electrons from the hole-electron pairs generated in the first photoelectric conversion layer 15 through photoelectric conversion can be captured as signal charges by the pixel electrode 11. For example, when holes are used as signal charges, holes can be selectively captured by the pixel electrode 11 by increasing the potential of the counter electrode 12 compared to the pixel electrode 11. The case of using holes as signal charges is illustrated below. Of course, electrons can also be used as signal charges; in this case, the potential of the counter electrode 12 can be decreased compared to the pixel electrode 11. The pixel electrode 11, opposite the counter electrode 12, captures either the positive or negative charges generated in the first photoelectric conversion layer 15 through photoelectric conversion by applying a suitable bias voltage between the counter electrode 12 and the pixel electrode 11.

[0129] The first photoelectric conversion layer 15 is a layer that absorbs photons to generate photocharge. Specifically, the first photoelectric conversion layer 15 receives incident light and generates electron-hole pairs. That is, the signal charge is either a hole or an electron. In this embodiment, the case where the signal charge is a hole is used as an example, but the signal charge can also be an electron. Holes, which are the signal charge, are captured by the pixel electrode 11. Electrons, which are the opposite polarity of the signal charge, are captured by the counter electrode 12.

[0130] The first photoelectric conversion layer 15 comprises semiconductor quantum dots and a covering material covering the semiconductor quantum dots. The first photoelectric conversion layer 15 may further comprise an acceptor material. An example of the acceptor material is the third material.

[0131] Semiconductor quantum dots receive incident light and generate electron-hole pairs, i.e., positive and negative charges. Semiconductor quantum dots function as donors, for example, relative to acceptor materials. That is, semiconductor quantum dots supply electrons to acceptor materials. Semiconductor quantum dots can also deliver electrons to pixel electrode 11 or counter electrode 12 without passing through acceptor materials.

[0132] Semiconductor quantum dots are materials that exhibit three-dimensional quantum confinement effects. Semiconductor quantum dots are nanocrystals with diameters ranging from approximately 2 nm to 10 nm, composed of about a few dozen atoms. Materials used for semiconductor quantum dots include, for example, group IV semiconductors such as Si or Ge, group IV-VI semiconductors such as PbS, PbSe, or PbTe, group III-V semiconductors such as InAs or InSb, or ternary mixed crystals such as HgCdTe or PbSnTe.

[0133] Semiconductor quantum dots have the property of absorbing light in the first wavelength range. Figure 6 This is a diagram showing an example of the absorption spectrum of a semiconductor quantum dot. Figure 6The absorption spectrum shown is that of a semiconductor quantum dot with a core material of PbS and a particle size of about 5 nm. Figure 6 The image also shows a spectrum that expands the 1200nm–1800nm ​​range by a factor of 10. For example... Figure 6 As shown, semiconductor quantum dots exhibit absorption peaks. Figure 6 In the example shown, the absorption peak wavelength of the semiconductor quantum dot falls within the infrared wavelength range. The absorption peak wavelength of the semiconductor quantum dot originates from its band gap and can be controlled by the material and particle size of the quantum dot core.

[0134] The first wavelength range is as follows: Figure 7 The absorption peak wavelengths shown represent the wavelength range in which semiconductor quantum dots absorb light and generate charge. That is, the first wavelength range is the wavelength range in which semiconductor quantum dots exhibit significant quantum efficiency. For example, the first wavelength range is the wavelength range in which the light absorption rate of semiconductor quantum dots reaches 1% or more.

[0135] Because semiconductor quantum dots exhibit absorption peaks within a specific narrow wavelength range, narrow-band wavelength imaging can be achieved by using the first photoelectric conversion layer 15 of semiconductor quantum dots. In particular, when semiconductor quantum dots exhibit light absorption within a narrow wavelength range in the infrared light wavelength range, high-sensitivity imaging utilizing the infrared light wavelength is possible. Examples of semiconductor quantum dots exhibiting absorption peaks within the infrared light wavelength range include those with core materials such as PbS, PbSe, PbTe, InAs, InSb, Ag2S, Ag2Se, Ag2Te, CuS, CuInS2, CuInSe2, AgInS2, AgInSe2, AgInTe2, ZnSnAs2, ZnSnSb2, CdGeAs2, CdSnAs2, HgCdTe, or InGaAs.

[0136] It should be noted that the first photoelectric conversion layer 15 may also contain a variety of semiconductor quantum dots with different particle sizes and / or a variety of semiconductor quantum dots with different core materials. Figure 7 This is a schematic diagram illustrating an example of the absorption spectrum of a semiconductor quantum dot containing multiple semiconductor quantum dots. For example... Figure 2 As shown, semiconductor quantum dots containing multiple semiconductor quantum dots with different particle sizes and / or multiple semiconductor quantum dots with different core materials have multiple absorption peaks.

[0137] In addition, the first photoelectric conversion layer 15 may contain materials that supply electrons to the acceptor material and function as a donor, in addition to semiconductor quantum dots.

[0138] The acceptor material functions as an acceptor relative to the semiconductor quantum dot. For example, the acceptor material is an electron acceptor material that accepts electrons from the semiconductor quantum dot. Thus, as electrons move from the electron-hole pairs generated by the semiconductor quantum dot to the acceptor material, the recombination of electron-hole pairs can be suppressed, thereby improving the photoelectric conversion efficiency of the first photoelectric conversion layer 15.

[0139] As acceptor materials, for example, C60 (fullerene) and PCBM (phenyl C60) are used. 61 Methyl butyrate), ICBA (indene C) 60 C60 derivatives such as biadditions, and oxide semiconductors such as TiO2, ZnO, and SnO2. It should be noted that the acceptor material is not limited to these; as mentioned above, any material capable of accepting electrons from semiconductor quantum dots is suitable as an acceptor material. A single acceptor material or a combination of multiple materials can be used.

[0140] A capping material is a material used to cover semiconductor quantum dots, used to suppress secondary particle formation, stabilize the film, and improve the conductivity between semiconductor quantum dots. The capping material has the property of absorbing light in a second wavelength range and emitting fluorescence in a third wavelength range. The capping material may include, for example, at least one of a ligand material and a matrix material.

[0141] The second wavelength range is the wavelength range in which the cover material exhibits significant absorption. Specifically, it is the wavelength range of light absorbed by the cover material that emits fluorescence to the extent that it affects the operation of the imaging device 100, such as image blurring, color mixing noise, or malfunctions. For example, it is the wavelength range in which the light absorption rate of the cover material reaches 1% or more. The second wavelength range also depends, for example, on the type of cover material, the fluorescence emission probability, the thickness of the first photoelectric conversion layer 15, the imaging purpose of the image sensor, and the photographic environment.

[0142] Furthermore, the third wavelength range is the wavelength range of fluorescence emitted when the covering material absorbs light in the second wavelength range. For example, in the case of P3HT, which is an example of a matrix material, such as... Figure 7 As shown, it emits significant fluorescence when absorbing light in the wavelength range of approximately 400 nm to approximately 650 nm.

[0143] The substrate material is a material used to fill the space between multiple semiconductor quantum dots in the first photoelectric conversion layer 15, thereby covering the semiconductor quantum dots and improving the conductivity of the first photoelectric conversion layer 15.

[0144] The substrate material is, for example, a material comprising at least one of semiconductor polymers, semiconductor copolymers, semiconductor oligomers, low-molecular-weight semiconductors, perovskite materials, and double perovskite materials. By including these materials in the substrate material, the conductivity between semiconductor quantum dots is improved, the conductivity within the first photoelectric conversion layer 15 is improved, and a first photoelectric conversion layer 15 with good film quality can be formed.

[0145] Semiconductor polymers and semiconductor oligomers include, for example, polymers using fluorene, fluorene derivatives, thiophene, thiophene derivatives, and phenylene vinylidene derivatives, which have a planar monomer backbone and are π-electron conjugated. Semiconductor polymers can also be semiconductor copolymers containing 50% or more of the aforementioned monomers. Specific examples of semiconductor polymers and semiconductor copolymers include P3HT, PFO (polyfluorene), PFO-BT (poly(fluorene-benzothiadiazole)), PT (polythiophene), and MDMO-PPV (poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylidene]).

[0146] Low-molecular-weight semiconductors are, for example, low-molecular-weight organic semiconductors that are soluble in solvents containing semiconductor quantum dots.

[0147] Perovskite materials include inorganic perovskite compounds such as CsPbBr2I and CsSnI3. Perovskite materials can also be organic-inorganic perovskite compounds such as CH3NH3SnI3.

[0148] Double perovskite materials can be, for example, inorganic double perovskite compounds. Double perovskite materials can also be organic-inorganic double perovskite compounds.

[0149] Furthermore, the ligand material is used to coat the surface modification base of the semiconductor quantum dots by modifying the surface of the semiconductor quantum dots. The ligand material is, for example, a ligand material with π-conjugation. This improves the conductivity between the semiconductor quantum dots, enhances the conductivity within the first photoelectric conversion layer 15, and suppresses the formation of secondary particles in the semiconductor quantum dots.

[0150] As specific ligand materials with π-conjugation, for example, organic molecules with molecular skeletons having π-conjugation systems such as polyphenylene skeletons or thiophene derivative skeletons, and having at least one terminal group such as a thiol group, carboxyl group, or amino group adsorbed on the surface of a semiconductor quantum dot.

[0151] The optical filter 16 has a non-zero light reflectance or a non-zero light absorptivity at at least a portion of the wavelengths in the second wavelength range where the covering material exhibits significant absorption. Furthermore, for example, the optical filter 16 has a non-zero light reflectance or a non-zero light absorptivity at wavelengths in the second wavelength range that include the wavelengths where the covering material exhibits maximum light absorptivity. Furthermore, for example, the optical filter 16 has a non-zero light reflectance or a non-zero light absorptivity across the entire second wavelength range.

[0152] The optical filter 16 reduces the transmittance of light in the second wavelength range by reflecting or absorbing light in the second wavelength range, thereby reducing the amount of light absorbed by the covering material and emitted as fluorescence.

[0153] Optical filter 16 can, for example, make light in the second wavelength range substantially non-transmittable. Making light in the second wavelength range substantially non-transmittable means that the light passing through optical filter 16 is absorbed by the covering material, which emits fluorescence. This fluorescence is not absorbed by the charge accumulation region, thus not significantly generating spurious signals or causing significant malfunctions in the control circuit.

[0154] The optical filter 16, for example, absorbs or reflects light with wavelengths below 1050 nm. As a result, light in the near-infrared to visible wavelength range becomes less easily absorbed by the covering material. Furthermore, the optical filter 16 can also absorb or reflect light with wavelengths below 700 nm.

[0155] While the transmittance of light in the second wavelength range in the optical filter 16 also depends on the absorption coefficient and fluorescence emission probability of the covering material, the thickness of the first photoelectric conversion layer 15, the imaging purpose of the imaging device 100, and the photographic environment, for example, the transmittance of the covering material with a light absorption rate of less than 1% across the entire second wavelength range. Specifically, the transmittance of light in the second wavelength range in the optical filter 16 may be less than 5%, or even less than 1%.

[0156] As described above, the optical filter 16 is located on the side closer to the imaging device than the first photoelectric conversion layer 15, absorbing or reflecting at least a portion of the light in the second wavelength range. This reduces the amount of light in the second wavelength range reaching the covering material. Consequently, it reduces the fluorescence emitted by the covering material due to excitation by light in the second wavelength range. That is, it reduces noise and other noise caused by the absorption of fluorescence emitted by the covering material by charge accumulation regions, etc.

[0157] Optical filter 16 allows light of at least a portion of the first wavelength range to pass through. In other words, optical filter 16 has significant transmittance for at least a portion of the first wavelength range. Significant transmittance means that the light passing through optical filter 16 is photoelectrically converted by semiconductor quantum dots to a degree that makes it capable of being captured by photography. While the transmittance of light in the first wavelength range in optical filter 16 also depends on photographic conditions and intent, it is, for example, 50% or more.

[0158] It should be noted that, regarding the first photoelectric conversion layer 15, as... Figure 5 As shown, when the semiconductor quantum dots contain a variety of semiconductor quantum dots with different particle sizes and / or a variety of semiconductor quantum dots with different core materials, the optical filter 16 can also have significant transmittance in the wavelength range of the absorption peak wavelength of any type of semiconductor quantum dots.

[0159] In this way, by transmitting light of at least a portion of the wavelength range through the optical filter 16, the reduction in photoelectric conversion function in the first photoelectric conversion layer 15 can be suppressed.

[0160] The optical filter 16 can be an absorptive filter using colored glass or the like, or a reflective filter made by stacking multiple dielectric films.

[0161] As an absorptive filter, an example is the tinted glass RG715 manufactured by Schott. Tinted glass RG715 has the characteristic of blocking light with wavelengths below 700 nm and allowing light with wavelengths above 800 nm to pass through. For example, when tinted glass RG715 is used in optical filter 16, optical filter 16 can allow light with an absorption peak wavelength of semiconductor quantum dots having a bandgap in the near-infrared region to pass through.

[0162] Furthermore, when the colored glass RG715 is used in the optical filter 16, if the upper limit of the second wavelength range of the matrix material, such as P3HT or CsPbBr2I, is below 700 nm, the optical filter 16 makes the light in the second wavelength range substantially non-transmittable.

[0163] The above are just examples. As long as an optical filter with suitable characteristics is selected based on the absorption spectrum of the covering material and the absorption spectrum of the semiconductor quantum dots, it is possible to achieve the desired result.

[0164] Optical filter 16 can be, for example, a long-pass filter that blocks light with wavelengths shorter than a certain wavelength while allowing light with wavelengths longer than that wavelength to pass through, or a band-pass filter that allows light within a specific wavelength range to pass through while blocking light with wavelengths shorter than that wavelength range and light with wavelengths longer than that wavelength range. For example, the transmission wavelength range of the band-pass filter can also be substantially the same as the absorption peak wavelength of the semiconductor quantum dot.

[0165] In addition, the optical filter 16 may be, for example, a notch filter that blocks the wavelength range including the second wavelength range and allows light with wavelengths shorter than that wavelength range and light with longer wavelengths to pass through.

[0166] like Figure 5 As shown, the optical filter 16 can be disposed directly above the counter electrode 12, or it can be disposed on the counter electrode 12. Figure 5 The sealing film (not shown) can also be configured on a device installed to protect the camera surface of the camera device 100. Figure 8 On the glass not shown in the image.

[0167] Furthermore, the optical filter 16 does not necessarily need to be located near the photoelectric conversion unit 13; it can also be located in the optical path of the imaging system. For example, the optical filter 16 can also be located between the imaging lens and the photoelectric conversion unit 13, inside the imaging lens, or in front of the imaging lens.

[0168] In addition, the optical filter 16 can also function as a sealing membrane to suppress the transmission of oxygen and water vapor.

[0169] Furthermore, the optical filter 16 can also be used, for example, with a multispectral imaging optical filter for changing the photographic spectrum of each pixel. Alternatively, a multispectral imaging optical filter can also function as the optical filter 16.

[0170] Furthermore, the optical filter 16 is not limited to a fixed optical filter. For example, it can also be configured to be switchable with other optical filters as needed.

[0171] (Implementation Method 2)

[0172] Next, Embodiment 2 will be described. In Embodiment 2, unlike Embodiment 1, an optical filter is not used as the first light-shielding body; instead, a first charge transport layer is used. Hereinafter, the description will focus on the differences from Embodiment 1, omitting or simplifying the description of commonalities.

[0173] [Structure of the photoelectric conversion unit]

[0174] Figure 8 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10a of the imaging device 100 in this embodiment. For example...Figure 8 As shown, pixel 10a differs from pixel 10 in Embodiment 1 in that it does not have an optical filter 16 and has a photoelectric conversion unit 13a instead of a photoelectric conversion unit 13.

[0175] The photoelectric conversion unit 13a includes: a plurality of pixel electrodes 11, a counter electrode 12, a first photoelectric conversion layer 15 located between the plurality of pixel electrodes 11 and the counter electrode 12, and a first charge transport layer 17 located between the counter electrode 12 and the first photoelectric conversion layer 15. In this embodiment, the counter electrode 12, the first charge transport layer 17, the first photoelectric conversion layer 15, and the plurality of pixel electrodes 11 are arranged sequentially from the incident side of light relative to the imaging device 100. That is, the first charge transport layer 17 is disposed on the incident side closer to light than the first photoelectric conversion layer 15. The first light shield in this embodiment includes the first charge transport layer 17.

[0176] like Figure 9 As shown, the first charge transport layer 17 is disposed in contact between the first photoelectric conversion layer 15 and the counter electrode 12. The first charge transport layer 17 has the function of transporting the charge captured by the counter electrode 12 from among the positive or negative charges generated in the first photoelectric conversion layer 15.

[0177] The first charge transport layer 17 has a non-zero light absorption rate at at least a portion of the wavelengths in the second wavelength range. Furthermore, for example, the first charge transport layer 17 has a non-zero light absorption rate at wavelengths in the second wavelength range that include the wavelengths where the covering material exhibits the maximum light absorption rate. Furthermore, for example, the first charge transport layer 17 has a non-zero light absorption rate across the entire second wavelength range. Furthermore, for example, the first charge transport layer 17 may also make light in the second wavelength range substantially non-transmissive.

[0178] The first charge transport layer 17, for example, absorbs light with wavelengths below 1050 nm. As a result, light in the near-infrared to visible wavelength range becomes less easily absorbed by the covering material. Furthermore, the first charge transport layer 17 can also absorb light with wavelengths below 700 nm.

[0179] The first charge transport layer 17 has significant transmittance for at least a portion of light in the first wavelength range. In the case where the first photoelectric conversion layer 15, which comprises semiconductor quantum dots, has multiple absorption peak wavelengths, the first charge transport layer 17 can also have significant transmittance at any absorption peak wavelength in the semiconductor quantum dots.

[0180] The light transmittance of the first charge transport layer 17 depends on the light absorption coefficient of the material constituting the first charge transport layer 17 and the thickness of the first charge transport layer 17.

[0181] The transmittance of light in the second wavelength range in the first charge transport layer 17 is, for example, less than 5%, or less than 1%.

[0182] The charge transport material of the first charge transport layer 17 is not particularly limited as long as it has the aforementioned light transmittance. Examples of charge transport materials for the first charge transport layer 17 include fullerenes and fullerene derivatives such as PCBM, perylene derivatives such as PTCDA and PTCBI, BT-CIC represented by the following structural formula (1), and CO represented by the following structural formula (2). i Non-fullerene-based low-bandgap organic semiconductors such as 8DFIC. These materials have relatively deep lowest empty orbital levels relative to the vacuum level, and tend to readily accept electrons from the semiconductor quantum dot at the interface with the quantum dot. When the first charge transport layer 17 is intended to transport electrons as negative charges, the charge transport material for the first charge transport layer 17 can be selected from materials having the aforementioned light transmittance properties, either from materials having a lowest empty orbital level or a lower conduction band level deeper than the lowest empty orbital level of the semiconductor quantum dot used. Conversely, when the first charge transport layer 17 is intended to transport holes as positive charges, the charge transport material for the first charge transport layer 17 can be selected from materials having the aforementioned light transmittance properties, either from materials having a highest occupied orbital level or a lower valence band level shallower than the highest occupied orbital level of the semiconductor quantum dot used.

[0183] [Chemical Formula 1]

[0184]

[0185] [Chemical Formula 2]

[0186]

[0187] The transmittance of the first charge transport layer 17 will be explained using C70, which exhibits negative charge transport properties, as an example. Figure 9 This indicates C60, C70, BT-CIC, and CO. i The absorption spectrum of 8DFIC.

[0188] like Figure 10 As shown, C60 readily absorbs light in the wavelength range below approximately 550 nm. Furthermore, C70 readily absorbs light in the wavelength range below approximately 700 nm. Additionally, BT-CIC readily absorbs light in the wavelength range of 600 nm to 950 nm. Furthermore, CO... i 8DFIC readily absorbs light in the wavelength range of 600nm to 1000nm.

[0189] also, Figure 10This is a graph showing the simulation results of light transmittance for C70 layers of different thicknesses. (About...) Figure 10 The simulation results for transmittance shown are illustrated, with the vertical axis representing transmittance and the horizontal axis representing wavelength. Figure 10 In this context, transmittance is represented by setting 1 to the case where all light of the wavelength along the horizontal axis is transmitted. For example, when converting transmittance to a percentage, 1 represents 100%, and 0.01 represents 1%. Furthermore, in... Figure 10 In the figure, the transmittance is shown on a logarithmic axis in the usual logarithmic form, with the vertical axis as the vertical axis.

[0190] like Figure 11 As shown, the transmittance of light with wavelengths below 600 nm in a C70 layer with a thickness of 400 nm or more is 5% or less, and the transmittance of light with wavelengths below 600 nm in a C70 layer with a thickness of 600 nm or more is 1% or less. Furthermore, C70 has the function of transporting negative charges. Therefore, in the imaging device 100 where the counter electrode 12 captures negative charges, the C70 layer functions as a charge transport layer and reduces the proportion of light with wavelengths below 600 nm reaching the first photoelectric conversion layer 15. Therefore, when the substrate material is CsPbBr2I, which is a perovskite material, the transmittance of the substrate material in the absorption wavelength range can be reduced, and noise-causing fluorescence emission can be suppressed.

[0191] From the viewpoint of reducing the transmittance of light in the second wavelength range, the thickness of the first charge transport layer 17 is, for example, 400 nm or more, or 600 nm or more.

[0192] The first charge transport layer 17 can be composed of a single type of material or multiple types of materials. For example, by mixing multiple materials with different absorption spectra, it is possible to reduce light transmittance over a wider wavelength range. For example, if CO has a large absorption coefficient in the wavelength range of 600 nm to 1000 nm... i When the first charge transport layer 17 is formed by mixing 8DFIC with a layer of C70, which has a large absorption coefficient in the wavelength range below 700 nm, the transmittance of light can be reduced over a wider wavelength range compared to the case where the first charge transport layer 17 is formed by C70 alone. Figure 11 This indicates CO with different thicknesses. i A graph showing the simulation results of the light transmittance of the hybrid layer of 8DFIC and C70. Figure 11 The text shows how to make CO i The result of a mixed layer with 8DFIC and C70 mixed in a 1:1 ratio. (Example) Figure 12 As shown, by setting the thickness of the hybrid layer to 1000 nm or more, it is possible to set the transmittance of light with wavelengths below 900 nm to 1% or less.

[0193] The first charge transport layer 17 can also be composed of a mixture of charge transport material and non-charge transport material. For example, a material that performs the function of transporting charge can be selected as the charge transport material, and a material with a desired absorption spectrum, such as absorbing light in the second wavelength range, can be selected as the non-charge transport material.

[0194] (Implementation Method 3)

[0195] Next, Embodiment 3 will be described. In Embodiment 3, unlike Embodiment 1, a second photoelectric conversion layer is used instead of an optical filter as the first light-shielding body. The following description will focus on the differences from Embodiment 1, omitting or simplifying the description of commonalities.

[0196] [Structure of the photoelectric conversion unit]

[0197] Figure 12 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10b of the imaging device 100 in this embodiment. For example... Figure 13 As shown, pixel 10b differs from pixel 10 in Embodiment 1 in that it does not have an optical filter 16 and has a photoelectric conversion unit 13b instead of a photoelectric conversion unit 13.

[0198] The photoelectric conversion unit 13b includes: a plurality of pixel electrodes 11, a counter electrode 12, a first photoelectric conversion layer 15 located between the plurality of pixel electrodes 11 and the counter electrode 12, and a second photoelectric conversion layer 18 located between the counter electrode 12 and the first photoelectric conversion layer 15. In this embodiment, the counter electrode 12, the second photoelectric conversion layer 18, the first photoelectric conversion layer 15, and the plurality of pixel electrodes 11 are arranged sequentially from the incident side of light relative to the imaging device 100. That is, the second photoelectric conversion layer 18 is disposed on the incident side closer to light than the first photoelectric conversion layer 15. The first light-shielding body in this embodiment includes the second photoelectric conversion layer 18.

[0199] The second photoelectric conversion layer 18 includes, for example, a donor material and an acceptor material. The donor material in the second photoelectric conversion layer 18 is a material different from that of a semiconductor quantum dot; it is an electron donor material that functions as a donor supplying electrons relative to the acceptor material contained in the second photoelectric conversion layer 18. The acceptor material in the second photoelectric conversion layer 18 functions as an electron acceptor material that accepts electrons relative to the donor material contained in the second photoelectric conversion layer 18. Even materials that emit fluorescence when the donor material absorbs light can suppress fluorescence generation if an appropriate amount of acceptor material is included, as the excited electrons move to the acceptor material.

[0200] The electron transport material contained in the first photoelectric conversion layer 15 and the acceptor material contained in the second photoelectric conversion layer 18 can be the same substance or different substances. For example, the acceptor material contained in the first photoelectric conversion layer 15 and the acceptor material contained in the second photoelectric conversion layer 18 can both be C60, or the acceptor material contained in the first photoelectric conversion layer 15 can be C60 and the acceptor material contained in the second photoelectric conversion layer 18 can be PCBM.

[0201] The second photoelectric conversion layer 18 has a non-zero light absorption rate at at least a portion of the wavelengths in the second wavelength range. Furthermore, for example, the second photoelectric conversion layer 18 has a non-zero light absorption rate at wavelengths in the second wavelength range that include the wavelengths where the covering material exhibits the maximum light absorption rate. Furthermore, for example, the second photoelectric conversion layer 18 has a non-zero light absorption rate across the entire second wavelength range. Furthermore, for example, the second photoelectric conversion layer 18 makes light in the second wavelength range substantially non-transmissive.

[0202] The second photoelectric conversion layer 18, for example, absorbs light with wavelengths below 1050 nm. Therefore, light in the near-infrared to visible wavelength range becomes less easily absorbed by the covering material. Furthermore, the second photoelectric conversion layer 18 can also absorb light with wavelengths below 700 nm.

[0203] The second photoelectric conversion layer 18 has significant transmittance for at least a portion of light in the first wavelength range. In the case where the photoelectric conversion layer comprising the semiconductor quantum dot has multiple absorption peak wavelengths, the second photoelectric conversion layer 18 can also have significant transmittance at any absorption peak wavelength of the semiconductor quantum dot.

[0204] For example, the second photoelectric conversion layer 18 preferably has a shorter wavelength of substantially nontransmissive light compared to the shortest wavelength among the multiple absorption peak wavelengths of the first photoelectric conversion layer 15 containing semiconductor quantum dots.

[0205] The light transmittance of the second photoelectric conversion layer 18 depends on the light absorption coefficient of each material constituting the second photoelectric conversion layer 18 and the thickness of the second photoelectric conversion layer 18.

[0206] Figure 13 This is a graph showing the absorption spectrum of a mixed film of SnNcCl2 and C70. In Figure 13 The absorption spectrum of the mixed film, where SnNcCl2 and C70 are mixed in a 1:1 ratio, is shown in the figure. Figure 14As shown, for example, in the second photoelectric conversion layer 18, when the donor material is SnNcCl2 (naphthalene phthalocyanine dichloride) and the acceptor material is C70, the second photoelectric conversion layer 18, made of a 1:1 mixture of the donor and acceptor materials, does not exhibit significant absorption with respect to wavelengths above approximately 1200 nm. That is, the mixed film allows light with wavelengths above approximately 1200 nm to pass through. On the other hand, the mixed film exhibits absorption with wavelengths below approximately 1200 nm. For example, in the wavelength range below 600 nm and the wavelength range of 720 nm to 980 nm, the light absorption coefficient of the mixed film is 2.0 × 10⁻⁶. 4 cm -1 The values ​​above. Therefore, if the mixed film has a thickness of 1000 nm or more, the transmittance of the mixed film in the wavelength range below 600 nm and the wavelength range of 720 nm to 980 nm is less than 1%. Therefore, even if CsPbBr2I is included as a substrate material in the first photoelectric conversion layer 15, the fluorescence generated by CsPbBr2I can be suppressed because the transmittance of CsPbBr2I in the second wavelength range of the second photoelectric conversion layer 18 is less than 1%. Furthermore, even if P3HT, CsSnI3, and CH3NH3SnI3 are included as substrate materials, the fluorescence generated by P3HT, CsSnI3, and CH3NH3SnI3 can be suppressed because the transmittance of P3HT, CsSnI3, and CH3NH3SnI3 in the second photoelectric conversion layer 18 is less than 1% for most wavelengths in the second wavelength range.

[0207] It should be noted that the value of the light absorption coefficient may vary depending on the mixing ratio, film quality, etc.

[0208] The donor material contained in the second photoelectric conversion layer 18 can also have quantum efficiency for light in the second wavelength range. As a result, the light in the second wavelength range absorbed by the donor material contained in the second photoelectric conversion layer 18 becomes the energy for generating electron-hole pairs, and becomes less likely to reach the covering material contained in the first photoelectric conversion layer 15.

[0209] The donor and acceptor materials contained in the second photoelectric conversion layer 18 are not particularly limited as long as they can form a mixed film with the aforementioned transmissivity. For the donor material, from the viewpoint of exhibiting a high absorption coefficient in the ultraviolet to near-infrared wavelength region and functioning well as a donor, examples include quinacridone, phthalocyanine, naphthyl phthalocyanine, quinacridone derivatives, phthalocyanine derivatives, and naphthyl phthalocyanine derivatives. Furthermore, the acceptor material can also be a material exhibiting a high light absorption coefficient in the 300 nm to 500 nm range, such as Alq3 (tris(8-hydroxyquinoline)aluminum). The donor material contained in the second photoelectric conversion layer 18 can be a single material or multiple donor materials can be included in the second photoelectric conversion layer 18. For example, by using multiple donor materials with different absorption spectra, it is possible to reduce light transmittance over a wider wavelength range.

[0210] (Implementation Method 4)

[0211] Next, Embodiment 4 will be described. In Embodiment 4, the difference from Embodiment 1 is that an optical filter is not used as the first light-shielding body, but a first light-shielding donor material is used. Hereinafter, the description will focus on the differences from Embodiment 1, and the description of the common points will be omitted or simplified.

[0212] [Structure of the photoelectric conversion unit]

[0213] Figure 14 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10c of the imaging device 100 in this embodiment. For example... Figure 15 As shown, pixel 10c differs from pixel 10 in Embodiment 1 in that it does not have an optical filter 16 and has a photoelectric conversion unit 13c instead of a photoelectric conversion unit 13.

[0214] The photoelectric conversion unit 13c includes: a plurality of pixel electrodes 11, a counter electrode 12, and a first photoelectric conversion layer 15a located between the plurality of pixel electrodes 11 and the counter electrode 12. In this embodiment, the counter electrode 12, the first photoelectric conversion layer 15a, and the plurality of pixel electrodes 11 are arranged sequentially from the incident side of light relative to the imaging device 100. The first photoelectric conversion layer 15a includes a semiconductor quantum dot, a cover material, and a first light-shielding donor material. That is, the first light-shielding donor material is located within the first photoelectric conversion layer 15a. The first light-shielding donor material is an example of a first material. The first light-shielding body in this embodiment includes the first light-shielding donor material. The first photoelectric conversion layer 15a may further include a acceptor material that functions as an acceptor relative to the semiconductor quantum dot and the first light-shielding donor material.

[0215] The first light-blocking donor material receives incident light and generates electron-hole pairs. The first light-blocking donor material is, for example, a material that functions as a donor relative to the acceptor material, unlike semiconductor quantum dots.

[0216] The first light-shielding donor material has a non-zero light absorptivity at at least a portion of the wavelengths in the second wavelength range. Furthermore, for example, the first light-shielding donor material has a non-zero light absorptivity at wavelengths in the second wavelength range that include the wavelengths where the covering material exhibits the maximum light absorptivity. Furthermore, for example, the first light-shielding donor material has a non-zero light absorptivity at all wavelengths in the second wavelength range. The light absorption coefficient of the first light-shielding donor material may also be equal to or greater than that of the covering material in the second wavelength range.

[0217] The first light-shielding donor material, for example, absorbs light with wavelengths below 1050 nm. As a result, light in the near-infrared to visible wavelength range becomes less easily absorbed by the covering material. Furthermore, the first light-shielding donor material can also absorb light with wavelengths below 700 nm.

[0218] In this embodiment, light in the second wavelength range may be incident on the first photoelectric conversion layer 15a and absorbed by the covering material. However, light in the second wavelength range may also be absorbed by the first light-shielding donor material. The light absorbed by the first light-shielding donor material becomes the energy for generating hole-electron pairs and is not absorbed by the covering material. Therefore, by including the first light-shielding donor material in the first photoelectric conversion layer 15a, the probability of the covering material absorbing light and generating fluorescence is reduced.

[0219] The greater the amount of the first light-shielding donor material contained in the first photoelectric conversion layer 15a relative to the covering material, the lower the probability that the covering material absorbs light and emits fluorescence. For example, if the first photoelectric conversion layer 15a contains equal amounts of covering material and the first light-shielding donor material, and the covering material and the first light-shielding donor material have the same absorption coefficient in the second wavelength range, then the probability that light in the second wavelength range is absorbed by the covering material becomes half that of the case where the first light-shielding donor material is not present.

[0220] The first light-blocking donor material is a material that possesses the aforementioned light-absorbing properties and functions as a donor relative to the acceptor material. Examples of first light-blocking donor materials include quinacridones, phthalocyanines, naphthylphthalocyanines, quinacridone derivatives, phthalocyanine derivatives, and naphthylphthalocyanine derivatives.

[0221] (Implementation Method 5)

[0222] Next, Embodiment 5 will be described. In Embodiment 5, a second light-shielding body is used instead of the first light-shielding body, unlike Embodiment 1. The second light-shielding body absorbs or reflects light of at least a portion of the wavelengths in the third wavelength range. The second light-shielding body is located within the first photoelectric conversion layer, or between the first photoelectric conversion layer and multiple pixel electrodes. Details of the second light-shielding body will be shown in various examples described below. The following description focuses on the differences from Embodiment 1, omitting or simplifying descriptions of commonalities.

[0223] [Structure of the photoelectric conversion unit]

[0224] Figure 15 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10d of the imaging device 100 in this embodiment. For example... Figure 16 As shown, pixel 10d differs from pixel 10 in Embodiment 1 in that it does not have an optical filter 16 and has a photoelectric conversion unit 13d instead of a photoelectric conversion unit 13.

[0225] The photoelectric conversion unit 13d includes: a plurality of pixel electrodes 11, a counter electrode 12, and a first photoelectric conversion layer 15b located between the plurality of pixel electrodes 11 and the counter electrode 12. In this embodiment, the counter electrode 12, the first photoelectric conversion layer 15b, and the plurality of pixel electrodes 11 are arranged sequentially from the incident side of light relative to the imaging device 100. The first photoelectric conversion layer 15b includes a semiconductor quantum dot, a cover material, and a second light-shielding donor material. That is, the second light-shielding donor material is located within the first photoelectric conversion layer 15b. The second light-shielding donor material is an example of a second material. In this embodiment, the second light-shielding body includes the second light-shielding donor material. The first photoelectric conversion layer 15b may further include a receptor material that functions as a receptor relative to the semiconductor quantum dot and the second light-shielding donor material.

[0226] The second light-blocking donor material receives incident light and generates electron-hole pairs. The second light-blocking donor material is, for example, a material that functions as a donor relative to the acceptor material, unlike semiconductor quantum dots.

[0227] The second light-shielding donor material has a non-zero light absorption rate at at least a portion of the wavelengths within the third wavelength range, which is the wavelength range in which the covering material emits fluorescence. Furthermore, for example, the second light-shielding donor material has a non-zero light absorption rate at wavelengths within the third wavelength range that include the wavelengths in which the covering material exhibits the maximum fluorescence intensity. Furthermore, for example, the second light-shielding donor material has a non-zero light absorption rate across the entire third wavelength range.

[0228] The second light-shielding donor material, for example, absorbs light with wavelengths below 1150 nm. As a result, light in the near-infrared to visible wavelength range becomes less likely to reach the semiconductor substrate 20. Furthermore, the second light-shielding donor material can also absorb light with wavelengths below 750 nm.

[0229] In this embodiment, light in the second wavelength range may be incident on the first photoelectric conversion layer 15b and absorbed by the covering material. When the covering material absorbs light in the second wavelength range, it emits fluorescence. However, since the second light-shielding donor material has a non-zero light absorption rate in the third wavelength range, it absorbs some or all of the fluorescence emitted by the covering material.

[0230] The fluorescence emitted by the cover material, absorbed by the second light-blocking donor material, becomes the energy for generating electron-hole pairs. The resulting electrons then separate from the second light-blocking donor material, for example, through the acceptor material, and the fluorescence disappears. Therefore, the amount of fluorescence reaching the semiconductor substrate 20 is reduced compared to the case where the second light-blocking donor material is absent. The greater the amount of the second light-blocking donor material contained in the first photoelectric conversion layer 15b relative to the cover material, the lower the probability that the fluorescence emitted by the cover material reaches the semiconductor substrate 20.

[0231] The second light-blocking donor material is a material that possesses the aforementioned light-absorbing properties and functions as a donor relative to the acceptor material. Examples of second light-blocking donor materials include quinacridones, phthalocyanines, naphthylphthalocyanines, quinacridone derivatives, phthalocyanine derivatives, and naphthylphthalocyanine derivatives.

[0232] (Implementation Method 6)

[0233] Next, Embodiment 6 will be described. In Embodiment 6, the second light-shielding body is used instead of the first light-shielding body, unlike Embodiment 1. Furthermore, in Embodiment 6, compared to Embodiment 5 which also uses a second light-shielding body, a second charge transport layer is used instead of the second light-shielding donor material as the second light-shielding body. Hereinafter, the description will focus on the differences from Embodiments 1 and 5, omitting or simplifying the description of commonalities.

[0234] [Structure of the photoelectric conversion unit]

[0235] Figure 16 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10e of the imaging device 100 in this embodiment. For example... Figure 16 As shown, pixel 10e differs from pixel 10 in Embodiment 1 in that it does not have an optical filter 16 and has a photoelectric conversion unit 13e instead of a photoelectric conversion unit 13.

[0236] The photoelectric conversion unit 13e includes: a plurality of pixel electrodes 11, a counter electrode 12, a first photoelectric conversion layer 15 located between the plurality of pixel electrodes 11 and the counter electrode 12, and a second charge transport layer 19 located between the first photoelectric conversion layer 15 and the plurality of pixel electrodes 11. In this embodiment, the counter electrode 12, the first photoelectric conversion layer 15, the second charge transport layer 19, and the plurality of pixel electrodes 11 are arranged sequentially from the incident side of the light relative to the imaging device 100. That is, the second charge transport layer 19 is disposed on the semiconductor substrate 20 side of the first photoelectric conversion layer 15. The second light shield in this embodiment includes the second charge transport layer 19.

[0237] like Figure 9 As shown, the second charge transport layer 19 is disposed in contact between the first photoelectric conversion layer 15 and the plurality of pixel electrodes 11. The second charge transport layer 19 has the function of transporting the charge captured by the pixel electrodes 11 from the positive or negative charges generated in the first photoelectric conversion layer 15.

[0238] The second charge transport layer 19 has a non-zero light absorption rate at at least a portion of the wavelengths in the third wavelength range. Furthermore, for example, the second charge transport layer 19 has a non-zero light absorption rate at wavelengths in the third wavelength range that include the wavelengths where the overlay material exhibits the maximum fluorescence intensity. Furthermore, for example, the second charge transport layer 19 has a non-zero light absorption rate at all wavelengths in the third wavelength range. Furthermore, for example, the second charge transport layer 19 makes light in the third wavelength range substantially non-transmissive.

[0239] The second charge transport layer 19, for example, absorbs light with wavelengths below 1150 nm. As a result, light in the near-infrared to visible wavelength range becomes less likely to reach the semiconductor substrate 20. Furthermore, the second charge transport layer 19 can also absorb light with wavelengths below 750 nm.

[0240] The transmittance of the second charge transport layer 19 depends on the light absorption coefficient of the material constituting the second charge transport layer 19 and the thickness of the second charge transport layer 19.

[0241] For example, regarding the absorption spectrum and transmittance of C70, which exhibits negative charge transport properties, as used in Embodiment 2, Figure 10 and Figure 10 As explained. Figure 17As shown, the transmittance of light with wavelengths below 600 nm in a C70 layer with a thickness of 400 nm or more is 5% or less, and the transmittance of light with wavelengths below 600 nm in a C70 layer with a thickness of 600 nm or more is 1% or less. Furthermore, C70 has the function of transporting negative charges. Therefore, in an imaging device where the pixel electrode 11 captures negative charges, the C70 layer functions as a charge transport layer and also reduces the proportion of light with wavelengths below 600 nm reaching the semiconductor substrate 20.

[0242] The charge transport material of the second charge transport layer 19 is not particularly limited as long as it has the aforementioned light transmittance properties. For example, in imaging devices where the pixel electrode 11 captures negative charges, examples of charge transport materials include fullerenes and fullerene derivatives such as PCBM, perylene derivatives such as PTCDA and PTCBI, and BT-CIC and CO2. i Non-fullerene-based low-bandgap organic semiconductors such as 8DFIC have electron transport materials with the lowest occupied orbital energy level based on the vacuum level being approximately 3.8 eV or higher. Conversely, for charge transport materials, in imaging devices where the pixel electrode 11 captures positive charges, examples include quinacridone derivatives, polyphenylene derivatives, phthalocyanine derivatives, anthocyanin derivatives, naphthylphthalocyanine derivatives such as SnNcCl2, benzothiadiazole derivatives, and benzobisthiadiazole derivatives, which have hole transport materials with the highest occupied orbital energy level based on the vacuum level being approximately 5.4 eV or lower. The second charge transport layer 19 can be composed of a single type of material or multiple types of materials. For example, by mixing multiple materials with different absorption spectra, the light transmittance can be reduced over a wider wavelength range. Furthermore, the second charge transport layer 19 can also be composed of a mixture of charge transport materials and non-charge transport materials. For example, materials that can perform the function of transporting charge can be selected as charge transport materials, while materials with the desired absorption spectrum, such as those that absorb light in the third wavelength range, can be selected as non-charge transport materials.

[0243] As described above, the second charge transport layer 19 is located closer to the semiconductor substrate 20 than the first photoelectric conversion layer 15, and absorbs or reflects at least a portion of the light in the third wavelength range. This reduces the amount of third wavelength light reaching the charge accumulation regions of the semiconductor substrate, including impurity regions, or the control circuit. Consequently, noise and other noise generated by the absorption of fluorescence emitted by the covering material in the charge accumulation regions can be reduced.

[0244] (Implementation Method 7)

[0245] Next, Embodiment 7 will be described. In Embodiment 7, a second light-shielding body is used in addition to the first light-shielding body, which differs from Embodiment 1. The following description will focus on the differences from Embodiment 1, omitting or simplifying the description of commonalities.

[0246] [Structure of the photoelectric conversion unit]

[0247] Figure 17 This is a schematic cross-sectional view showing the cross-sectional structure of the plurality of pixels 10f of the imaging device 100 in this embodiment. For example... ​ As shown, pixel 10f differs from pixel 10 in Embodiment 1 in that it has a photoelectric conversion unit 13f instead of a photoelectric conversion unit 13.

[0248] The photoelectric conversion unit 13f includes a plurality of pixel electrodes 11, a counter electrode 12, and a first photoelectric conversion layer 15b located between the plurality of pixel electrodes 11 and the counter electrode 12. Furthermore, an optical filter 16 is provided on the counter electrode 12 of the photoelectric conversion unit 13f. In this embodiment, the optical filter 16, the counter electrode 12, the first photoelectric conversion layer 15b, and the plurality of pixel electrodes 11 are arranged sequentially from the light incident side relative to the imaging device 100. That is, the optical filter 16 is disposed on the light incident side closer to the first photoelectric conversion layer 15b than the first photoelectric conversion layer 15b. The first photoelectric conversion layer 15b, similar to that in Embodiment 5, includes a semiconductor quantum dot, a cover material, and a second light-shielding donor material. The first photoelectric conversion layer 15b may further include a receptor material that functions as a receptor relative to the semiconductor quantum dot and the second light-shielding donor material.

[0249] The imaging device 100 of this embodiment includes a first light-shielding body and a second light-shielding body. Furthermore, the first light-shielding body of this embodiment includes an optical filter 16, and the second light-shielding body of this embodiment includes a second light-shielding donor material. Therefore, the optical filter 16 absorbs or reflects light in the second wavelength range, suppressing fluorescence emitted by the cover material. Even when the cover material emits fluorescence, the second light-shielding donor material absorbs the fluorescence, thus suppressing fluorescence from reaching the semiconductor substrate 20.

[0250] (Other implementation methods)

[0251] The above description describes one or more camera devices based on various embodiments, but this disclosure is not limited to these embodiments. Any modifications conceived by those skilled in the art, applied to these embodiments, or combinations of elements from different embodiments, that are incorporated into these embodiments are also included within the scope of this disclosure, provided they do not depart from its spirit.

[0252] For example, in the above embodiment, the first photoelectric conversion layer is a semiconductor quantum dot layer formed by mixing a covering material of semiconductor quantum dots such as a ligand material or a matrix material of a π-conjugated compound, but it is not limited to this. The first photoelectric conversion layer may be a photoelectric conversion layer containing both semiconductor quantum dots and a receptor material that functions as a receptor relative to the semiconductor quantum dots, or it may be a two-layer photoelectric conversion layer formed by bonding a layer containing semiconductor quantum dots and a layer containing receptor material.

[0253] Furthermore, for example, in Embodiment 6 described above, a second charge transport layer is provided as a second light-shielding body, but it is not limited to this. As a second light-shielding body, a third photoelectric conversion layer that absorbs at least a portion of the wavelengths in the third wavelength range may be provided instead of the second charge transport layer.

[0254] Alternatively, for example, it may be a camera device composed of multiple combinations of the first light-shielding body and the second light-shielding body used in each embodiment.

[0255] Industrial availability

[0256] The camera device disclosed herein can be applied to various camera systems and sensor systems, such as medical cameras, surveillance cameras, vehicle-mounted cameras, rangefinder cameras, microscope cameras, drone cameras, and robot cameras, utilizing high-sensitivity imaging with infrared wavelengths.

[0257] Explanation of symbols

[0258] Pixels 10, 10a, 10b, 10c, 10d, 10e, 10f

[0259] 11-pixel electrode

[0260] 12 Opposite Electrodes

[0261] 13, 13a, 13b, 13c, 13d, 13e, 13f Photoelectric conversion unit

[0262] 14 Signal Detection Circuit

[0263] 15, 15a, 15b First photoelectric conversion layer

[0264] 16 Optical Filters

[0265] 17 First charge transport layer

[0266] 18 Second photoelectric conversion layer

[0267] 19 Second charge transport layer

[0268] 20 Semiconductor substrates

[0269] 20t component separation area

[0270] 24 Signal detection transistor

[0271] Impurity regions at 24d, 24s, 26s, 28d, and 28s

[0272] 24g, 26g, 28g gate electrodes

[0273] 26 Addressing transistors

[0274] 28 Reset transistor

[0275] 32 Voltage supply circuit

[0276] 34 Reset Voltage Source

[0277] 36 Vertical Scanning Circuit

[0278] 37-column signal processing circuits

[0279] 38 Horizontal Signal Readout Circuit

[0280] 40 Power cord

[0281] 41 Charge accumulation node

[0282] 42 Bias control line

[0283] 44 Reset voltage line

[0284] 46 Addressing control lines

[0285] 47 Vertical signal line

[0286] 48 Reset control line

[0287] 49 Horizontal Common Signal Line

[0288] 50 interlayer insulation layers

[0289] 52 Plugs

[0290] 53 Wiring

[0291] 54, 55 Contact plugs

[0292] 56 Wiring Layer

[0293] 100 camera devices

[0294] 200A, 200B Semiconductor Quantum Dots

[0295] 210 cores

[0296] 220 shell

[0297] 230 ligands

Claims

1. A camera device comprising: Semiconductor substrate; Multiple pixel electrodes are located above the semiconductor substrate and are electrically connected to the semiconductor substrate, respectively. Opposing electrode, which is located above the plurality of pixel electrodes; A first photoelectric conversion layer is located between the plurality of pixel electrodes and the opposing electrode; and At least one first light-shielding body is located within or above the first photoelectric conversion layer. The first photoelectric conversion layer includes: Semiconductor quantum dots, which have the property of absorbing light in the first wavelength range; and A covering material, which covers the semiconductor quantum dots, has the property of absorbing light in the second wavelength range and emitting fluorescence in the third wavelength range. The at least one first light-shielding body absorbs or reflects light of at least a portion of the wavelength range of the second wavelength range.

2. The camera device according to claim 1, wherein, The at least one first light-shielding body includes an optical filter located above the counter electrode, which absorbs or reflects light of at least a portion of the wavelengths in the second wavelength range.

3. The camera device according to claim 1 or 2, wherein, The at least one first light-shielding body includes a first charge transport layer located between the first photoelectric conversion layer and the counter electrode, which absorbs light of at least a portion of the wavelengths in the second wavelength range.

4. The camera device according to claim 1 or 2, wherein, The at least one first light-shielding body includes a second photoelectric conversion layer, which is located between the first photoelectric conversion layer and the counter electrode, and absorbs light of at least a portion of the wavelengths in the second wavelength range.

5. The camera device according to claim 1 or 2, wherein, The at least one first light-shielding body comprises a first material that absorbs light of at least a portion of the wavelengths within the second wavelength range, unlike the semiconductor quantum dot. The first material is located within the first photoelectric conversion layer.

6. The camera device according to claim 1 or 2, wherein, The at least one first light-shielding body allows light of at least a portion of the wavelengths of the first wavelength range to pass through.

7. The camera device according to claim 1 or 2, wherein, The at least one first light-shielding body absorbs or reflects light with wavelengths below 1050 nm.

8. The imaging device according to claim 1 or 2, further comprising at least one second light-shielding body, the at least one second light-shielding body being located within the first photoelectric conversion layer or between the first photoelectric conversion layer and the plurality of pixel electrodes, absorbing or reflecting light of at least a portion of the wavelength range of the third wavelength range.

9. A camera device comprising: Semiconductor substrate; Multiple pixel electrodes are located above the semiconductor substrate and are electrically connected to the semiconductor substrate respectively; Opposing electrode, which is located above the plurality of pixel electrodes; A first photoelectric conversion layer is located between the plurality of pixel electrodes and the opposing electrode; and At least one second light-shielding body is located within the first photoelectric conversion layer or between the first photoelectric conversion layer and the plurality of pixel electrodes. The first photoelectric conversion layer includes: Semiconductor quantum dots, which have the property of absorbing light in the first wavelength range; and A covering material, which covers the semiconductor quantum dots, has the property of absorbing light in the second wavelength range and emitting fluorescence in the third wavelength range. The at least one second light-shielding body absorbs or reflects light of at least a portion of the wavelength range of the third wavelength range.

10. The camera device according to claim 9, wherein, The at least one second light-shielding body comprises a second material that absorbs light of at least a portion of the wavelengths within the third wavelength range, unlike the semiconductor quantum dot. The second material is located within the first photoelectric conversion layer.

11. The camera device according to claim 9 or 10, wherein, The at least one second light-shielding body includes a second charge transport layer located between the first photoelectric conversion layer and the plurality of pixel electrodes, which absorbs light of at least a portion of the wavelengths in the third wavelength range.

12. The camera device according to claim 1 or 9, wherein, The covering material comprises at least one selected from the group consisting of a matrix material and a ligand material having π-conjugation. The matrix material comprises at least one selected from the group consisting of semiconductor polymers, semiconductor copolymers, semiconductor oligomers, low molecular weight semiconductors, perovskite materials, and double perovskite materials.

13. The camera device according to claim 1 or 9, wherein, The first photoelectric conversion layer includes a third material that functions as an acceptor relative to the semiconductor quantum dot.

14. The camera device according to claim 5, wherein, The first photoelectric conversion layer includes a third material that functions as an acceptor relative to the semiconductor quantum dot and the first material.

15. The camera device according to claim 10, wherein, The first photoelectric conversion layer includes a third material that functions as an acceptor relative to the semiconductor quantum dot and the second material.

16. The camera device according to claim 1 or 9, wherein, The semiconductor substrate contains silicon.

Images