Photoelectric conversion element manufacturing method and optical sensor

Abstract

To provide a manufacturing method for a photoelectric conversion element including an active layer with high photoelectric effect sensitivity, and an optical sensor including a photoelectric conversion element in which the photoelectric effect sensitivity of an active layer is high.SOLUTION: A manufacturing method for a photoelectric conversion element includes an active layer generating step of generating an active layer with a repeating unit expressed in Chemical Formula 1. The active layer generating step includes a first layer forming step of applying a first liquid including polyamic acid to form a first layer, a first heating step of heating the first layer for 20 to 60 minutes at 120°C, and a second heating step of heating the first layer for 10 minutes at 230°C to 280°C. An optical sensor includes a substrate and a sensor part stacked on the substrate. The sensor part includes a detection electrode, an electron transport layer, an active layer, a hole transport layer, and a counter electrode, and a photoelectric conversion element stacked on the substrate. The active layer is formed of a polyimide material with a repeating unit expressed by Chemical Formula 5.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a photoelectric conversion element and an optical sensor. [Background technology]

[0002] An optical sensor has a photoelectric conversion element such as a photodiode. The photoelectric conversion element disclosed in Non-Patent Document 1 has an active layer (polyimide layer) made of polyimide. Non-Patent Document 1 also discloses that polyamic acid, a precursor of polyimide, is heat-treated at 300°C for 2 hours to crystallize the polyimide and produce an active layer (polyimide layer) that exhibits a photoelectric effect. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] Akio Takimoto et al., "Electrophotographic and structural studies on novel photoconductive polyimide films," Journal of Applied Physics, Vol. 70 (No. 5), 1991, p. 2799 Summary of the Invention [Problem to be solved by the invention]

[0004] The active layer obtained in Non-Patent Document 1 has low sensitivity of the photoelectric effect.

[0005] The present disclosure aims to provide a method for manufacturing a photoelectric conversion element having a highly sensitive photoelectric effect in the active layer, and also to provide an optical sensor including a photoelectric conversion element having a highly sensitive photoelectric effect in the active layer. [Means for solving the problem]

[0006] A method for producing a photoelectric conversion element according to a first aspect of the present disclosure includes an active layer forming step of forming an active layer having a repeating unit represented by the following chemical formula 1. The active layer forming step includes a first layer forming step of applying a polyamic acid precursor to form a first layer, a first heating step of heating the first layer at 120°C for 20 to 60 minutes, and a second heating step of heating the first layer at 230°C to 280°C for 10 minutes.

[0007] [ka]

[0008] A method for producing a photoelectric conversion element according to a second aspect of the present disclosure includes an active layer forming step of forming an active layer having a repeating unit represented by the following chemical formula 2. The active layer forming step includes a first layer forming step of applying a polyamic acid solution, which is a precursor of the following chemical formula 2, to form a first layer, a first heating step of heating the first layer at 120°C for 20 to 60 minutes, and a second heating step of heating the first layer at 180°C to 280°C for 10 minutes.

[0009] [ka]

[0010] A method for producing a photoelectric conversion element according to a third aspect of the present disclosure includes an active layer forming step of forming an active layer having a repeating unit represented by the following chemical formula 3. The active layer forming step includes a first layer forming step of applying a precursor polyamic acid having a repeating unit represented by the following chemical formula 4 to form a first layer, a first heating step of heating the first layer at 120°C for 20 to 60 minutes, and a second heating step of heating the first layer at 180°C to 280°C for 10 minutes.

[0011] [ka]

[0012] [ka]

[0013] An optical sensor according to one embodiment of the present disclosure includes a substrate and a sensor unit laminated on the substrate. The sensor unit has a detection electrode, an electron transport layer, an active layer, a hole transport layer, and a counter electrode, and also has a photoelectric conversion element laminated on the substrate. The active layer is made of a polyimide-based material having a repeating unit represented by the following chemical formula 5.

[0014] [ka] [Brief explanation of the drawings]

[0015] [Figure 1A] FIG. 1A is a cross-sectional view of an optical sensor according to a first embodiment. [Figure 1B] FIG. 1B is a cross-sectional view of an optical sensor according to the first modification. [Figure 1C] FIG. 1C is a cross-sectional view of an optical sensor according to Modification 2. As shown in FIG. [Figure 1D] FIG. 1D is a cross-sectional view of an optical sensor according to Modification 3. As shown in FIG. [Figure 2] FIG. 2 is a plan view showing the sensor substrate according to the first embodiment. [Figure 3] FIG. 3 is a block diagram illustrating an example of the configuration of the detection device according to the first embodiment. [Figure 4] FIG. 4 is a circuit diagram showing the detection device according to the first embodiment. [Figure 5] FIG. 5 is a circuit diagram showing a plurality of partial detection areas according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a schematic cross-sectional configuration of the sensor unit. [Figure 7] FIG. 7 is a diagram showing a manufacturing process of the photodiode according to the first embodiment. [Figure 8] FIG. 8 is a diagram showing a manufacturing process of the active layer according to the first embodiment. [Figure 9]FIG. 9 is a cross-sectional view showing a schematic cross-sectional configuration of a sensor unit according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing a manufacturing process of the active layer according to the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a schematic cross-sectional configuration of a sensor unit according to the third embodiment. [Figure 12] FIG. 12 is a diagram showing a manufacturing process of the active layer according to the third embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing a schematic cross-sectional configuration of a sensor unit according to the fourth embodiment. [Figure 14] FIG. 14 is a diagram showing a manufacturing process of the active layer according to the fourth embodiment. [Figure 15] FIG. 15 is a cross-sectional view showing a modified example of the active layer of the fourth embodiment. [Figure 16] FIG. 16 is a cross-sectional view showing a modified example of the photoelectric conversion element. [Figure 17] FIG. 17 is a chart showing the results of X-ray diffraction analysis of Samples 1 to 8. [Figure 18] FIG. 18 is a graph showing the relationship between the half width of the X-ray spectrum and the substrate temperature during film formation for Samples 2, 3, 4, 5, 6, 7, and 8. [Figure 19] FIG. 19 is a chart showing the results of X-ray diffraction analysis of Samples 11 to 16. [Figure 20] FIG. 20 is a graph showing the relationship between the half width of the X-ray spectrum and the substrate temperature during film formation for Samples 11 to 16. DETAILED DESCRIPTION OF THE INVENTION

[0016] Modes (embodiments) for carrying out the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. Note that the disclosure is merely an example, and any appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the present disclosure are naturally included within the scope of the present disclosure. Furthermore, for clarity of explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this disclosure and each figure, elements similar to those described above with reference to the previous figures may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0017] In this specification and claims, when expressing an aspect of placing another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is placed directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is placed above a certain structure via yet another structure.

[0018] (Embodiment 1) Fig. 1A is a cross-sectional view of an optical sensor according to embodiment 1. Fig. 1B is a cross-sectional view of an optical sensor according to modification 1. Fig. 1C is a cross-sectional view of an optical sensor according to modification 2. Fig. 1D is a cross-sectional view of an optical sensor according to modification 3.

[0019] In the description of the embodiments, a case where a photoelectric conversion element (referred to as a photodiode 30 in the embodiments) is applied to an optical sensor 120 will be described as an example. As shown in FIG. 1A, the optical sensor 120 is a detection instrument with an illumination device, which has a detection device 1 and an illumination device 121. The detection device 1 has a sensor substrate 2, an optical filter 7, an adhesive layer 125, and a cover member 122. The sensor substrate 2, the optical filter 7, the adhesive layer 125, the cover member 122, and the illumination device 121 are stacked in this order in a direction perpendicular to the surface of the sensor substrate 2.

[0020] The adhesive layer 125 bonds the optical filter 7 and the cover member 122. Note that the adhesive layer 125 does not need to bond the entire surfaces of the optical filter 7 and the cover member 122 to each other. For example, the adhesive layer 125 may be configured to bond only the area corresponding to the peripheral area GA, without bonding the area corresponding to the detection area AA. The cover member 122 is a member for protecting the sensor substrate 2 and the optical filter 7, and covers the sensor substrate 2 and the optical filter 7. The cover member 122 is, for example, a glass substrate.

[0021] The lighting device 121 may be a light source such as a light emitting diode (LED) or a display panel. The display panel may be, for example, an organic light emitting diode (OLED) or an inorganic EL display (micro LED, mini LED). Alternatively, the display panel may be a liquid crystal display panel (LCD) using liquid crystal elements as display elements, or an electrophoretic display panel (EPD) using electrophoretic elements as display elements.

[0022] In such an optical sensor 120, light L1 emitted from the illumination device 121 is reflected by the finger Fg. The detection device 1 detects the light L2 reflected by the finger Fg and detects irregularities (e.g., a fingerprint) on the surface of the finger Fg. In addition to detecting a fingerprint, the detection device 1 may detect light L2 reflected inside the finger Fg and detect information related to the living body. The information related to the living body may include, for example, an image of blood vessels such as veins, a pulse rate, and a pulse wave. The color of the light L1 emitted from the illumination device 121 may be varied depending on the detection target.

[0023] 1A. As shown in FIG. 1B, the illumination device 121 may be, for example, a so-called side-light type front light, which uses a cover member 122 as a light guide plate provided at a position corresponding to the detection area AA of the detection device 1 and has a plurality of light sources 123 lined up at one end or both ends of the cover member 122. That is, the cover member 122 has a light irradiation surface 121a that emits light, and is a component of the illumination device 121. According to this illumination device 121, light L1 is emitted from the light irradiation surface 121a of the cover member 122 toward the finger Fg, which is the detection target. As the light source, for example, an LED that emits light of a predetermined color is used.

[0024] Furthermore, as shown in FIG. 1C, an illumination device 121 may be provided on the side or above the cover member 122, and light L1 may be irradiated onto the finger Fg from the side or above the finger Fg.

[0025] Furthermore, as shown in FIG. 1D, the illumination device 121 may be a so-called direct backlight provided on the back surface of the detection device 1.

[0026] Additionally, although not particularly shown, the lighting device 121 itself may serve as the cover member 122. Alternatively, the lighting device 121 may not be provided, and sunlight reflected from the finger Fg may be detected.

[0027] 2 is a plan view showing the sensor substrate according to the first embodiment. Note that the first direction Dx shown in FIG. 2 and subsequent figures is a direction in a plane parallel to the substrate 21. The second direction Dy is a direction in a plane parallel to the substrate 21, and is a direction perpendicular to the first direction Dx. Note that the second direction Dy may intersect with the first direction Dx without being perpendicular thereto. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy, and is a normal direction to the substrate 21.

[0028] As shown in FIG. 2, the sensor substrate 2 includes a substrate 21, a sensor section 10, a scanning line driving circuit 15, a signal line selection circuit 16, a detection circuit 48, a control circuit 102, and a power supply circuit 103.

[0029] The substrate 21 is a drive circuit substrate that has TFTs (Thin Film Transistors) such as switching elements Tr and various wiring lines such as gate lines GCL and signal lines SGL, and drives the sensor unit 10. The substrate 21 is also called a backplane or array substrate. A control substrate 101 is electrically connected to the substrate 21 via a wiring substrate 110. The wiring substrate 110 is, for example, a flexible printed circuit board or a rigid substrate. The wiring substrate 110 is provided with a detection circuit 48. The control substrate 101 is provided with a control circuit 102 and a power supply circuit 103. The control circuit 102 is, for example, an FPGA (Field Programmable Gate Array). The control circuit 102 supplies control signals to the sensor unit 10, the scanning line driving circuit 15, and the signal line selection circuit 16. The power supply circuit 103 supplies voltage signals such as a sensor power supply signal VDDSNS (see FIG. 5) to the sensor unit 10, the scanning line driving circuit 15, and the signal line selection circuit 16. In this embodiment, the case where the detection circuit 48 is disposed on the wiring substrate 110 has been exemplified, but the detection circuit 48 may be disposed on the substrate 21.

[0030] The substrate 21 has a detection area AA and a peripheral area GA. The elements (detection elements 3) of the sensor unit 10 are provided in the detection area AA. The peripheral area GA is an area outside the detection area AA where the elements (detection elements 3) are not provided. A scanning line driving circuit 15 and a signal line selection circuit 16 are provided in the peripheral area GA.

[0031] The sensor unit 10 includes a plurality of detection elements 3 as an optical sensor. The detection elements 3 are photodiodes 30. The photodiodes 30 are photoelectric conversion elements that output an electrical signal in response to light irradiated thereon. More specifically, the photodiodes 30 are OPDs (organic photodiodes). The detection elements 3 (photodiodes 30) are arranged in a matrix in the detection area AA. The photodiodes 30 perform detection in accordance with gate drive signals (e.g., reset control signal RST, read control signal RD) supplied from the scanning line drive circuit 15. The plurality of photodiodes 30 output electrical signals in response to light irradiated thereon as detection signals Vdet to the signal line selection circuit 16. The detection device 1 detects information related to a living organism based on the detection signals Vdet from the plurality of photodiodes 30.

[0032] Fig. 3 is a block diagram showing an example of the configuration of the detection device according to embodiment 1. As shown in Fig. 3, the detection device 1 further includes a detection control circuit 11 and a detection unit 40. Some or all of the functions of the detection control circuit 11 are included in a control circuit 102. In addition, some or all of the functions of the detection unit 40 other than the detection circuit 48 are included in the control circuit 102.

[0033] The detection control circuit 11 is a circuit that supplies control signals to the scanning line driving circuit 15, the signal line selection circuit 16, and the detection unit 40, respectively, and controls their operations. The detection control circuit 11 supplies various control signals, such as a start signal STV and a clock signal CK, to the scanning line driving circuit 15. The detection control circuit 11 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 16.

[0034] The scanning line driving circuit 15 is a circuit that drives a plurality of scanning lines (gate lines GCL (see FIG. 4)) based on various control signals. The scanning line driving circuit 15 selects a plurality of scanning lines sequentially or simultaneously, and supplies gate driving signals to the selected scanning lines. In this way, the scanning line driving circuit 15 selects a plurality of photodiodes 30 connected to the scanning lines.

[0035] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of signal lines SGL (see FIG. 4). The signal line selection circuit 16 is, for example, a multiplexer. The signal line selection circuit 16 connects the selected output signal line SL to the detection circuit 48 based on a selection signal ASW supplied from the detection control circuit 11. As a result, the signal line selection circuit 16 outputs the detection signal Vdet of the photodiode 30 to the detection unit 40.

[0036] The detection unit 40 includes a detection circuit 48, a signal processing circuit 44, a coordinate extraction circuit 45, a memory circuit 46, and a detection timing control circuit 47. Based on a control signal supplied from the detection control circuit 11, the detection timing control circuit 47 controls the detection circuit 48, the signal processing circuit 44, and the coordinate extraction circuit 45 so that they operate in synchronization.

[0037] The detection circuit 48 is, for example, an analog front end (AFE). The detection circuit 48 is a signal processing circuit having at least the functions of a detection signal amplifier circuit 42 and an A / D conversion circuit 43. The detection signal amplifier circuit 42 is a circuit that amplifies the detection signal Vdet, and is, for example, an integration circuit. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal.

[0038] The signal processing circuit 44 is a logic circuit that detects a predetermined physical quantity input to the sensor unit 10 based on the output signal of the detection circuit 48. When the finger Fg comes into contact with or close to the detection surface, the signal processing circuit 44 can detect unevenness on the surface of the finger Fg or palm based on the signal from the detection circuit 48. The signal processing circuit 44 may also detect information about the living body based on the signal from the detection circuit 48. The information about the living body includes, for example, an image of the blood vessels of the finger Fg or palm, a pulse wave, a pulse rate, and blood oxygen saturation.

[0039] The memory circuit 46 temporarily stores the signals calculated by the signal processing circuit 44. The memory circuit 46 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0040] The coordinate extraction circuit 45 is a logic circuit that calculates the detected coordinates of the unevenness of the surface of the finger Fg or the like when the signal processing circuit 44 detects contact or proximity of the finger Fg. The coordinate extraction circuit 45 is also a logic circuit that calculates the detected coordinates of the blood vessels of the finger Fg or the palm. The coordinate extraction circuit 45 combines the detection signals Vdet output from each detection element 3 of the sensor unit 10 to generate two-dimensional information that indicates the shape of the unevenness of the surface of the finger Fg or the like. Note that the coordinate extraction circuit 45 may output the detection signal Vdet as the sensor output Vo without calculating the detection coordinates.

[0041] Next, an example of the circuit configuration of the detection device 1 will be described. Fig. 4 is a circuit diagram showing the detection device according to embodiment 1. As shown in Fig. 4, the sensor unit 10 has a plurality of partial detection areas PAA arranged in a matrix. A photodiode 30 is provided in each of the plurality of partial detection areas PAA.

[0042] The gate lines GCL extend in a first direction Dx and are connected to a plurality of partial detection areas PAA arranged in the first direction Dx. Furthermore, a plurality of gate lines GCL(1), GCL(2), ..., GCL(8) are arranged in a second direction Dy and are each connected to a scanning line driving circuit 15. In the following description, when it is not necessary to distinguish between the plurality of gate lines GCL(1), GCL(2), ..., GCL(8), they will be simply referred to as gate lines GCL. Furthermore, for ease of understanding, eight gate lines GCL are shown in FIG. 4, but this is merely an example, and M gate lines GCL (M is 8 or more, for example, M=256) may be arranged.

[0043] The signal line SGL extends in the second direction Dy and is connected to the photodiodes 30 of the plurality of partial detection areas PAA arranged in the second direction Dy. Furthermore, the plurality of signal lines SGL(1), SGL(2), ..., SGL(12) are arranged in the first direction Dx and are each connected to the signal line selection circuit 16 and the reset circuit 17. In the following description, when it is not necessary to distinguish between the plurality of signal lines SGL(1), SGL(2), ..., SGL(12), they will simply be referred to as signal line SGL.

[0044] For ease of understanding, 12 signal lines SGL are shown, but this is merely an example, and N signal lines SGL (N is 12 or more, for example, N=252) may be arranged. In addition, in FIG. 4, the sensor unit 10 is provided between the signal line selection circuit 16 and the reset circuit 17. However, this is not limiting, and the signal line selection circuit 16 and the reset circuit 17 may be connected to the ends of the signal lines SGL in the same direction. Furthermore, the effective area of ​​one sensor is, for example, substantially 50×50 μm. 2 The resolution of the detection area AA is, for example, substantially 508 ppi, the number of sensors arranged in the detection area AA is, for example, 252 cells x 256 cells, and the area of ​​the detection area AA is, for example, 12.6 x 12.8 mm 2 It is said that.

[0045] The scanning line driving circuit 15 receives various control signals, such as a start signal STV, a clock signal CK, and a reset signal RST1, from the control circuit 102 (see FIG. 2). Based on the various control signals, the scanning line driving circuit 15 sequentially selects multiple gate lines GCL(1), GCL(2), ..., GCL(8) in a time-division manner. The scanning line driving circuit 15 supplies a gate driving signal Vgcl to the selected gate line GCL. As a result, the gate driving signal is supplied to multiple first switching elements Tr connected to the gate line GCL, and multiple partial detection areas PAA arranged in the first direction Dx are selected as detection targets.

[0046] The scanning line driving circuit 15 may perform different driving for each detection mode of a fingerprint and a plurality of different pieces of biological information (pulse wave, pulse, blood vessel image, blood oxygen concentration, etc.) For example, the scanning line driving circuit 15 may drive a plurality of gate lines GCL in a bundle.

[0047] The signal line selection circuit 16 has a plurality of selection signal lines Lsel, a plurality of output signal lines Lout, and a third switching element TrS. The plurality of third switching elements TrS are provided corresponding to the plurality of signal lines SGL, respectively. The six signal lines SGL(1), SGL(2), ..., SGL(6) are connected to a common output signal line Lout1. The six signal lines SGL(7), SGL(8), ..., SGL(12) are connected to a common output signal line Lout2. The output signal lines Lout1 and Lout2 are each connected to a detection circuit 48.

[0048] Here, the signal lines SGL(1), SGL(2), ..., SGL(6) are defined as a first signal line block, and the signal lines SGL(7), SGL(8), ..., SGL(12) are defined as a second signal line block. The multiple selection signal lines Lsel are connected to the gates of the third switching elements TrS included in one signal line block. Furthermore, one selection signal line Lsel is connected to the gates of the third switching elements TrS of multiple signal line blocks.

[0049] The control circuit 102 (see FIG. 2) sequentially supplies the selection signal ASW to the selection signal line Lsel. As a result, the signal line selection circuit 16 sequentially selects the signal lines SGL in one signal line block in a time-division manner through the operation of the third switching element TrS. The signal line selection circuit 16 also selects one signal line SGL from each of the multiple signal line blocks. With this configuration, the detection device 1 can reduce the number of ICs (Integrated Circuits) including the detection circuit 48 or the number of IC terminals. The signal line selection circuit 16 may also bundle multiple signal lines SGL and connect them to the detection circuit 48.

[0050] 4, the reset circuit 17 includes a reference signal line Lvr, a reset signal line Lrst, and a fourth switching element TrR. The fourth switching element TrR is provided corresponding to the plurality of signal lines SGL. The reference signal line Lvr is connected to one of the sources or drains of the plurality of fourth switching elements TrR. The reset signal line Lrst is connected to the gates of the plurality of fourth switching elements TrR.

[0051] The control circuit 102 supplies a reset signal RST2 to the reset signal line Lrst. This turns on the multiple fourth switching elements TrR, and the multiple signal lines SGL are electrically connected to the reference signal line Lvr. The power supply circuit 103 supplies a reference signal COM to the reference signal line Lvr. This causes the reference signal COM to be supplied to the capacitive elements Ca (see FIG. 5) included in the multiple partial detection areas PAA.

[0052] Fig. 5 is a circuit diagram showing multiple partial detection areas according to the first embodiment. Fig. 5 also shows the circuit configuration of a detection circuit 48. As shown in Fig. 5, the partial detection area PAA includes a photodiode 30, a capacitive element Ca, and a first switching element Tr. The capacitive element Ca is a capacitance (sensor capacitance) formed in the photodiode 30, and is equivalently connected in parallel with the photodiode 30.

[0053] 5 shows two gate lines GCL(m) and GCL(m+1) aligned in the second direction Dy among the multiple gate lines GCL. Also, two signal lines SGL(n) and SGL(n+1) aligned in the first direction Dx among the multiple signal lines SGL. The partial detection area PAA is an area surrounded by the gate lines GCL and the signal lines SGL.

[0054] The first switching element Tr is provided corresponding to the photodiode 30. The first switching element Tr is configured by a thin film transistor, and in this example, is configured by an n-channel MOS (Metal Oxide Semiconductor) TFT (Thin Film Transistor).

[0055] The gates of the first switching elements Tr belonging to the partial detection areas PAA aligned in the first direction Dx are connected to the gate line GCL. The sources of the first switching elements Tr belonging to the partial detection areas PAA aligned in the second direction Dy are connected to the signal line SGL. The drains of the first switching elements Tr are connected to the cathodes of the photodiodes 30 and the capacitance elements Ca.

[0056] A sensor power supply signal VDDSNS is supplied to the anode of the photodiode 30 from the power supply circuit 103. In addition, a reference signal COM, which becomes the initial potential of the signal line SGL and the capacitance element Ca, is supplied from the power supply circuit 103 to the signal line SGL and the capacitance element Ca.

[0057] When light is irradiated onto the partial detection area PAA, a current corresponding to the amount of light flows through the photodiode 30, causing charge to accumulate in the capacitance element Ca. When the first switching element Tr is turned on, a current corresponding to the charge accumulated in the capacitance element Ca flows through the signal line SGL. The signal line SGL is connected to the detection circuit 48 via the third switching element TrS of the signal line selection circuit 16. This allows the detection device 1 to detect a signal corresponding to the amount of light irradiated onto the photodiode 30 for each partial detection area PAA or for each block unit PAG.

[0058] During the readout period, the switch SSW of the detection circuit 48 is turned on, and the detection circuit 48 is connected to the signal line SGL. The detection signal amplifier circuit 42 of the detection circuit 48 converts fluctuations in the current supplied from the signal line SGL into fluctuations in voltage and amplifies the voltage. A reference potential (Vref) having a fixed potential is input to the non-inverting input terminal (+) of the detection signal amplifier circuit 42, and the signal line SGL is connected to the inverting input terminal (-). In this embodiment, a signal identical to the reference signal COM is input as the reference potential (Vref) voltage. The signal processing circuit 44 (see FIG. 2) calculates the difference between the detection signal Vdet when light is irradiated and the detection signal Vdet when light is not irradiated as the sensor output voltage Vo. The detection signal amplifier circuit 42 also has a capacitance element Cb and a reset switch RSW. During the reset period, the reset switch RSW is turned on, and the charge of the capacitance element Cb is reset.

[0059] Next, the configurations of the photodiode 30 and the optical filter 7 will be described. Fig. 6 is a cross-sectional view showing a schematic cross-sectional configuration of the sensor unit. As shown in Fig. 6, the sensor unit 10 includes a photodiode 30 (photoelectric conversion element) and a sealing layer 25. Then, the optical filter 7 is provided on the sealing layer 25.

[0060] The photodiode 30 has a detection electrode 31, an electron transport layer 32, an active layer 33, a hole transport layer 34, and a counter electrode 35. The detection electrode 31, the electron transport layer 32, the active layer 33, the hole transport layer 34, and the counter electrode 35 are stacked on the sensor substrate 2 in this order.

[0061] The detection electrode 31 is electrically connected to the first switching element Tr (see FIG. 5) of the sensor substrate 2 via a contact hole (not shown). The detection electrode 31 is the cathode of the photodiode 30 and is an electrode for reading out the detection signal Vdet. The detection electrode 31 is made of, for example, silver (Ag) or titanium (Ti). Alternatively, the detection electrode 31 may be made of, for example, a translucent conductive material such as ITO (Indium Tin Oxide).

[0062] The electron transport layer 32 and the hole transport layer 34 are provided to allow holes and electrons generated in the active layer 33 to easily reach the counter electrode 35 or the detection electrode 31. The electron transport layer 32 and the hole transport layer 34 are made of, for example, zinc oxide (ZnO) and a polythiophene-based conductive polymer (PEDOT:PSS).

[0063] The active layer 33 is a thin film made of polyimide having a repeating unit represented by the following chemical formula 6. The active layer 33 has a crystalline polyimide structure and has a photoelectric conversion function. Therefore, when the active layer 33 is irradiated with light, holes and electrons are generated in the active layer 33. The holes and electrons generated in the active layer 33 move through the electron transport layer 32 and hole transport layer 34, respectively, toward the detection electrode 31 or the counter electrode 35.

[0064] [ka]

[0065] The counter electrode 35 is an anode of the photodiode 30, and is an electrode for supplying a power supply signal VDDSNS to the active layer 33. The counter electrode 35 and the detection electrode 31 face each other with the active layer 33 interposed therebetween. The counter electrode 35 is made of, for example, ITO.

[0066] The sealing layer 25 is a layer that covers the photodiodes 30 and flattens the sensor section 10. More specifically, the sealing layer 25 is filled between the photodiodes 30 and covers the counter electrodes 35 of each photodiode 30. The material of the sealing layer 25 is aluminum oxide (Al2O3).

[0067] The optical filter 7 is an optical element that transmits light along the third direction Dz and suppresses stray light in directions other than the third direction Dz. The optical filter 7 includes a base 70 and multiple apertures 71. The base 70 functions as a light-blocking member that does not transmit light. The apertures 71 are cylindrical through-holes formed in the base 70. The base 70 is formed directly on the sealing layer 25. The multiple apertures 71 are arranged along the first direction Dx-second direction Dy plane of the base 70. Note that the optical filter of the present disclosure is not limited to this. The optical filter may be a multi-layer pinhole type formed by alternately stacking layers with multiple holes (pinholes) and transparent resin layers. Alternatively, the optical filter may be a microlens type formed by alternately stacking layers with pinholes and transparent resin layers and overlaying microlenses on the pinholes on the surface where light enters.

[0068] Next, a method for manufacturing the photodiode 30 will be described. Fig. 7 is a diagram showing the manufacturing process of the photodiode according to embodiment 1. Fig. 8 is a diagram showing the manufacturing process of the active layer according to embodiment 1. The method for manufacturing the photodiode 30 includes step S1 of forming the detection electrode 31, step S2 of forming the electron transport layer 32, step S3 of forming the active layer 33, step S4 of forming the hole transport layer 34, and step S5 of forming the counter electrode 35.

[0069] In step S1, a conductive material such as ITO is applied to the sensor substrate 2 by, for example, vacuum deposition, sputtering, ion plating, or plating, to form the detection electrode 31.

[0070] In step S2, a zinc acetate ethanol solution is applied onto the detection electrode 31 to form a thin film of zinc acetate sol-gel. Next, the thin film is heated to form an electron transport layer 32 made of ZnO.

[0071] The step S3 of generating an active layer includes a first layer forming step S11, a first heating step S12, and a second heating step S13, as shown in Fig. 8. The step S3 of generating an active layer may be referred to as an active layer generating step.

[0072] The first layer forming step S11 is a step of applying a solution of polyamic acid, which is a precursor of polyimide, onto the electron transport layer 32 to form the first layer 51.

[0073] The first heating step S12 is a step of heating the first layer 51 at 120°C for 60 minutes. As a heating method, for example, as shown in FIG. 8, the sensor substrate 2 is placed in an oven 50 and heated. Note that polyamic acid undergoes an imidization reaction when heated to 200°C or higher. Therefore, in the first heating step S12, the first layer 51 does not undergo an imidization reaction, the amount of remaining solvent decreases, and the viscosity increases.

[0074] The second heating step S13 is a step of heating the first layer 51 at 230°C to 280°C for 10 minutes, for example, in an oven 50. This second heating step S13 causes an imidization reaction in the first layer 51, resulting in the active layer 33. Note that the first heating step S12 and the second heating step S13 of the present disclosure may use a heating means other than the oven 50.

[0075] 7, in step S4, PEDOT:PSS is applied onto the active layer 33 and then heated, thereby forming a hole transport layer .

[0076] In step S5, a film of a conductive material such as ITO or IZO is formed on the hole transport layer 34 by, for example, vacuum deposition, sputtering, ion plating, or plating, thereby forming the counter electrode 35.

[0077] As described above, the photodiode (photoelectric conversion element) 30 manufactured by the manufacturing method of the first embodiment has higher crystallinity and superior photoelectric conversion sensitivity than conventional photodiodes. Furthermore, the active layer 33 is formed of polyimide and does not undergo thermal degradation up to 320°C. Note that the heat-resistant temperature of a bulk heterostructure active layer containing a mixture of PCBM (phenyl C61-butyric acid methyl ester), P3HT (poly(3-hexylthiophene)), and F8BT (F8-alt-benzothiadiazole) is 100°C. Therefore, the photodiode (photoelectric conversion element) 30 manufactured by the manufacturing method of the first embodiment has a higher heat-resistant temperature than conventional photodiodes. Therefore, conventionally, forming an optical filter 7 on the sealing layer 25 covering the photodiode 30 could potentially thermally affect the active layer 33. Therefore, the optical filter 7 was manufactured separately and attached to the sensor unit 10 with adhesive tape. However, according to the active layer 33 of the first embodiment, even if the optical filter 7 is formed directly on the sealing layer 25 by, for example, a photolithography process, the influence on the active layer 33 is small. In other words, adhesive tape for adhering the optical filter 7 is not required, and the detection device 1 can be made thinner.

[0078] Although the photoelectric conversion element according to the first embodiment has been described above, the photoelectric conversion element of the present disclosure is not limited to the above. Other embodiments will be described below, focusing on differences from the photoelectric conversion element according to the first embodiment.

[0079] (Embodiment 2) 9 is a cross-sectional view showing a schematic cross-sectional configuration of a sensor unit according to embodiment 2. The photodiode 30A according to embodiment 2 differs from the photodiode 30 according to embodiment 1 in that it includes an active layer 33A instead of the active layer 33.

[0080] The active layer 33A according to the second embodiment is a thin film formed of polyimide having a repeating unit represented by the following chemical formula 7. The active layer 33A has a crystalline structure and has a photoelectric conversion function.

[0081] [ka]

[0082] 10 is a diagram showing the manufacturing process of the active layer according to embodiment 2. As in embodiment 1, the manufacturing method of the photodiode 30A includes step S1 of forming the detection electrode 31, step S2 of forming the electron transport layer 32, step S3 of forming the active layer 33A, step S4 of forming the hole transport layer 34, and step S5 of forming the counter electrode 35 (see FIG. 7). Furthermore, as shown in FIG. 10, the step of forming the active layer 33A includes a first layer forming step S21, a first heating step S22, and a second heating step S23.

[0083] In the first layer forming step S21, a polyamic acid solution, which is a precursor, is applied onto the electron transport layer 32 to form the first layer 52.

[0084] In the first heating step S22, the sensor substrate 2 is placed in an oven 50, and the first layer 52 is heated at 120°C for 20 to 60 minutes. Note that the polyamic acid (precursor) undergoes an imidization reaction when heated to 200°C or higher. Therefore, in the first heating step S22, the first layer 52 does not undergo an imidization reaction, and the amount of remaining solvent decreases.

[0085] The second heating step S23 is a step of heating the first layer 52 at 180° C. to 260° C. for 10 minutes in the oven 50. This causes the polyamic acid (precursor) of the first layer 52 to undergo an imidization reaction, forming the active layer 33A.

[0086] The manufacturing method of embodiment 2 also makes it possible to manufacture a photodiode 30 having high crystallinity in the active layer 33A and excellent photoelectric conversion sensitivity. In addition, the heat resistance temperature of the active layer 33A is high, at 300°C or higher, and the optical filter 7 can be formed directly on the sealing layer 25, allowing the detection device 1 to be made thinner.

[0087] (Embodiment 3) 11 is a cross-sectional view showing a schematic cross-sectional configuration of a sensor unit according to embodiment 3. The photodiode 30B according to embodiment 3 differs from the photodiode 30 according to embodiment 1 in that it includes an active layer 33B instead of the active layer 33.

[0088] The active layer 33B according to the third embodiment is a thin film formed of polyimide having a repeating unit represented by the following chemical formula 8. The active layer 33B has a crystalline structure and a photoelectric conversion function.

[0089] [ka]

[0090] 12 is a diagram showing the manufacturing process of the active layer according to embodiment 3. As in embodiment 1, the manufacturing method of the photodiode 30B includes step S1 of forming the detection electrode 31, step S2 of forming the electron transport layer 32, step S3 of forming the active layer 33B, step S4 of forming the hole transport layer 34, and step S5 of forming the counter electrode 35 (see FIG. 7). Furthermore, as shown in FIG. 12, the step of forming the active layer 33B includes a first layer forming step S31, a first heating step S32, and a second heating step S33.

[0091] The first layer forming step S31 is a step of applying a polyamic acid precursor onto the electron transport layer 32 to form the first layer 53. The polyamic acid has a repeating unit represented by the following chemical formula 9. The polyamic acid of the following formula can be obtained by a dehydration condensation reaction between an acid anhydride and a diamine compound.

[0092] [ka]

[0093] The first heating step S32 is a step of heating the first layer 53 in an oven 50 at 120°C for 20 minutes. The polyamic acid of the following formula undergoes an imidization reaction when heated to 200°C or higher. Therefore, the first layer 53 does not undergo an imidization reaction in the first heating step S32.

[0094] The second heating step S33 is a step of heating the first layer 53 for 10 minutes at 200° C. to 240° C. in the oven 50. This causes the polyamic acid in the first layer 53 to undergo an imidization reaction, forming the active layer 33B.

[0095] As described above, even with the manufacturing method of the third embodiment, it is possible to manufacture a photodiode 30B having high crystallinity in the active layer 33B and excellent photoelectric conversion sensitivity. The heat resistance temperature of the active layer 33B is high at 300°C, and the optical filter 7 can be formed directly on the sealing layer 25 (sensor portion 10). This allows the detection device 1 to be made thinner.

[0096] (Embodiment 4) 13 is a cross-sectional view showing a schematic cross-sectional configuration of a sensor unit according to embodiment 4. The photodiode 30C according to embodiment 4 differs from the photodiode 30 according to embodiment 1 in that it includes an active layer 33C instead of the active layer 33.

[0097] The active layer 33C according to the third embodiment is formed by heterojunction of an n-type semiconductor 38 and a p-type semiconductor 37. The p-type semiconductor 37 is one of the polyimides represented by Chemical Formula 5, Chemical Formula 6, and Chemical Formula 7 described in the first to third embodiments, and has a crystalline structure. Therefore, the p-type semiconductor 37 alone has a photoelectric conversion function.

[0098] The n-type semiconductor 38 is formed by heat-treating and crystallizing a soluble porphyrin or phthalocyanine compound. The n-type semiconductor 38 has a plurality of columnar portions 38a extending toward the hole transport layer 34, forming a three-dimensional pn junction between the n-type semiconductor 38 and the p-type semiconductor 37. This allows a large amount of current to be extracted from the interface between the n-type semiconductor 38 and the p-type semiconductor 37. Therefore, the photoelectric sensitivity of the active layer 33D is improved compared to a single layer of the p-type semiconductor 37, in other words, compared to the active layers 33, 33A, and 33B of Embodiments 1 to 3. Next, a method for manufacturing the active layer 33C of Embodiment 4 will be described.

[0099] Fig. 14 is a diagram showing the manufacturing process of the active layer according to embodiment 4. As shown in Fig. 14, the process of generating the active layer 33C includes an underlayer forming step S41, an underlayer heating step S42, a first layer forming step S43, a first heating step S44, and a second heating step S45.

[0100] The underlayer forming step S41 is a step of applying a soluble porphyrin or phthalocyanine compound onto the electron transport layer 32 to form the underlayer .

[0101] The underlayer heating step S42 is a step of heating the underlayer 54 at 150° C. for 30 minutes in the oven 50. As a result, the underlayer 54 hardens and becomes part of the n-type semiconductor 38.

[0102] The first layer formation step S43 is a step of applying a mixture of one of the polyimides represented by Chemical Formula 5, Chemical Formula 6, and Chemical Formula 7 and the soluble porphyrin or phthalocyanine compound used in the underlayer 54 upward onto a part of the n-type semiconductor 38, thereby forming a first layer 55.

[0103] In the first heating step S44, the sensor substrate 2 is placed in an oven 50, and the first layer 55 is heated at 120° C. for 60 minutes.

[0104] Subsequently, in a second heating step S45, the first layer 55 is heated at 120°C to 180°C for 10 minutes. As a result, as shown in Fig. 14, the soluble porphyrin or phthalocyanine compound contained in the first layer 55 forms pillar portions 38a (see Fig. 13) that extend toward the hole transport layer 34, using the n-type semiconductor 38 as a base material. The polyimide also undergoes an imidization reaction, producing a crystallized p-type semiconductor 37.

[0105] 15 is a cross-sectional view showing a modified example of the active layer of Embodiment 4. In the present disclosure, in the heterojunction active layer 33C, the soluble porphyrin or phthalocyanine compound in the first layer 55 does not need to be formed into a columnar shape in the second heating step S45. For example, as shown in FIG. 15, an n-type semiconductor 38 and a p-type semiconductor 37 may be mixed.

[0106] As described above, according to the manufacturing method of the fourth embodiment, it is possible to manufacture a photodiode 30D (photoelectric conversion element) with further improved sensitivity of the photoelectric effect.

[0107] Fig. 16 is a cross-sectional view showing a modified example of a photoelectric conversion element. Although the embodiments have been described above, the photodiode (photoelectric conversion element) of the present disclosure may be a photodiode 30D in which the stacking order of the detection electrode 31, the electron transport layer 32, the active layer 33, the hole transport layer 34, and the counter electrode 35 is reversed from that described in the first to fourth embodiments, as shown in Fig. 16.

[0108] (Example) Next, examples will be described. In example 1, a photodiode (photoelectric conversion element) was manufactured by the manufacturing method of embodiment 1, and its crystallinity was confirmed. In example 2, a photodiode (photoelectric conversion element) was manufactured by the manufacturing method of embodiment 1, and its crystallinity was confirmed. Examples 1 and 2 will be described below.

[0109] Example 1 FIG. 17 is a chart showing the results of X-ray diffraction analysis of Samples 1 to 8. FIG. 18 is a graph showing the relationship between the half-width of the X-ray spectrum and the substrate temperature during film formation for Samples 2, 3, 4, 5, 6, 7, and 8. In Example 1, a total of eight photodiodes (hereinafter referred to as Samples 1, 2, ..., and 8) were manufactured. Some of the samples were manufactured using the manufacturing method of Embodiment 1, and the rest were manufactured using a manufacturing method other than the manufacturing method of Embodiment 1 (Comparative Example).

[0110] More specifically, in Samples 1 to 8, the first layer 51 was formed using a first liquid made of polyamic acid in the first layer forming step S11. In Samples 1 to 6, the first layer 51 was heated at 120°C for 60 minutes in the first heating step S12. On the other hand, Samples 7 and 8 did not undergo the first heating step S12. Therefore, Samples 7 and 8 are comparative examples.

[0111] Furthermore, the heating temperature and time were varied for Samples 1 to 8 in the second heating step S13. Specifically, Sample 1 was heated at 120°C for 20 to 60 minutes. Sample 2 was heated at 200°C for 10 minutes. Sample 3 was heated at 220°C for 10 minutes. Sample 4 was heated at 240°C for 10 minutes. Sample 5 was heated at 260°C for 10 minutes. Sample 6 was heated at 280°C for 10 minutes. Sample 7 was heated at 280°C for 60 minutes. Sample 8 was heated at 290°C for 60 minutes. From the above, Samples 1, 2, 3, 7, and 8 are comparative examples that do not satisfy the condition of heating at 230°C to 280°C for 10 minutes shown in the embodiment.

[0112] Next, the crystallinity of Samples 1 to 8 was analyzed using an X-ray diffractometer. The analysis results are shown in FIG.

[0113] As shown in FIG. 17, no clear peaks were observed in Samples 1 to 3 and Sample 7. This indicates that the polyimide (active layer 33) in Samples 1 to 3 and Sample 7 was not crystallized in the second heating step S13 and was mainly in an amorphous state. Samples 4 to 6 had clear diffraction peaks at 2θ=18.5° and 2θ=22.3°. The diffraction peak values ​​were also high. This indicated that the polyimide (active layer 33) was sufficiently crystallized. Furthermore, although Sample 8 had a diffraction peak at 2θ=22.3°, the peak value was small, indicating insufficient crystallinity.

[0114] Next, the half-widths of the X-ray spectra of Samples 2, 3, 4, 5, 6, 7, and 8 were measured during X-ray diffraction (2θ = 18.5° for Samples 2, 3, 4, 5, and 6, and 2θ = 22.3° for Samples 7 and 8) to determine the crystallite sizes. Note that Sample 8, like Sample 7, is a photodiode produced without undergoing the first heating step S12, and the heating temperatures in the second heating step S13 were 280 and 290°C. The half-widths of the X-ray spectra are shown in FIG. 18.

[0115] As shown in Figure 18, the half-width decreased in the following order: Sample 2, Sample 3, Sample 4, Sample 5, and Sample 6. This indicates that, within the range of 200°C to 260°C in the second heating step, the crystallite size increased and the crystallinity improved as the heating temperature increased. On the other hand, Samples 7 and 8 had half-width values ​​of 0.7 or more, indicating high polycrystalline properties. From the above, Samples 4, 5, and 6, which had heating temperatures in the second heating step S13 between 230°C and 280°C, were found to have higher crystallinity and superior photoelectric conversion sensitivity than Samples 7 and 8.

[0116] Example 2 FIG. 19 is a chart showing the results of X-ray diffraction analysis of Samples 11 to 16. FIG. 20 is a graph showing the relationship between the half-width of the X-ray spectrum and the substrate temperature during film formation for Samples 11 to 16 according to Example 2. Next, Example 2 will be described. In Example 2, a total of six photodiodes (hereinafter referred to as Samples 11, 12, ..., and 16) were manufactured. Some of the samples were manufactured using the manufacturing method of Embodiment 2, and the rest were manufactured using a manufacturing method other than the manufacturing method of Embodiment 2 (Comparative Example).

[0117] More specifically, for Samples 11 to 16, in the first layer forming step S21, a solution of amic acid, which is a precursor of Chemical Formula 2, was applied to form the first layer 52. For Samples 11 to 16, in the first heating step S12, the first layer 52 was heated at 120°C for 20 to 60 minutes.

[0118] Furthermore, the heating temperature was changed for each of Samples 11 to 16 in the second heating step S13. Specifically, Sample 11 was heated at 180°C. Sample 12 was heated at 200°C. Sample 13 was heated at 220°C. Sample 14 was heated at 240°C. Sample 15 was heated at 260°C. Sample 16 was heated at 280°C. From the above, Samples 11 to 15 satisfy the condition of heating at 180°C to 260°C for 10 minutes set forth in Embodiment 2, and only Sample 16 is a comparative example that does not satisfy the condition of the embodiment. The heating time was 10 minutes for all of Samples 11 to 16.

[0119] Next, the crystallinity of Samples 11 to 16 was analyzed using an X-ray diffractometer. The analysis results are shown in Figure 19. In addition, the half-width of the X-ray spectrum during X-ray diffraction (2θ = 18.6° and 2θ = 22.0°) was measured to determine the crystallite size. The half-width of the X-ray spectrum is shown in Figure 20.

[0120] As shown in Figure 19, Samples 11 to 16 had diffraction peaks at 2θ = 18.6° and 2θ = 22.0°. Samples 11 to 15 also had high diffraction peak values, indicating that the polyimide films were sufficiently crystallized. Sample 16 had a small peak value and was not sufficiently crystalline. Therefore, it was found that sufficient crystallization was achieved when the condition of heating at 180°C to 260°C for 10 minutes in the second heating step S23 was met.

[0121] 20, among Samples 11 to 15, Sample 13 (heating temperature: 220°C) exhibited a half-width value of 0.4 or less, showing the strongest crystal uniformity. Therefore, it was found that among Samples 11 to 15, Sample 13 had the highest crystallinity and was excellent in photoelectric conversion sensitivity. [Explanation of symbols]

[0122] 120 Optical Sensor 121 Lighting equipment 1. Detection device 2 Sensor board 3. Detector element 7 Optical Filter 10 Sensor section 15 Scanning line driving circuit 16 Signal line selection circuit 21 PCB 25 Sealing layer 30 Photodiode (photoelectric conversion element) 31 Detection electrode 32 Electron transport layer 33 Active layer 34 Hole transport layer 35 Counter electrode 51, 52, 53, 55 1st layer 70 base 71 Aperture 102 control circuit 103 Power supply circuit S11, S21, S31, S43 1st layer formation process S12, S22, S32, S44 1st heating process S13, S23, S33, S45 2nd heating process S41 Lower stratum formation engineering S42 Lower stratum heating project

Claims

1. An active layer forming step of forming an active layer having a repeating unit represented by the following chemical formula 1, The active layer generating step includes: a base layer forming step of applying a soluble porphyrin or phthalocyanine compound to form a base layer for the active layer; a base layer heating step of heating the base layer at 150°C; a first layer forming step of applying a polyamic acid precursor to form a first layer; a first heating step of heating the first layer at 120°C for 20 to 60 minutes; a second heating step of heating the first layer at 230°C to 280°C for 10 minutes; and In the first layer forming step, after the underlayer heating step, the soluble porphyrin or phthalocyanine compound selected for the underlayer is added to the precursor and mixed, and the mixture is applied to form the first layer. A method for manufacturing a photoelectric conversion element. 【Chemical 1】

2. An active layer forming step of forming an active layer having a repeating unit represented by the following chemical formula 2, The active layer generating step includes: a base layer forming step of applying a soluble porphyrin or phthalocyanine compound to form a base layer for the active layer; a base layer heating step of heating the base layer at 150°C; a first layer forming step of applying a polyamic acid solution, which is a precursor of Chemical Formula 2 below, to form a first layer; a first heating step of heating the first layer at 120°C for 20 to 60 minutes; a second heating step of heating the first layer at 180°C to 280°C for 10 minutes; and In the first layer forming step, after the underlayer heating step, the soluble porphyrin or phthalocyanine compound selected for the underlayer is added to the precursor and mixed, and the mixture is applied to form the first layer. A method for manufacturing a photoelectric conversion element. 【Chemistry 2】

3. an active layer forming step of forming an active layer having a repeating unit represented by the following chemical formula 3, The active layer generating step includes: a base layer forming step of applying a soluble porphyrin or phthalocyanine compound to form a base layer for the active layer; a base layer heating step of heating the base layer at 150°C; a first layer forming step of applying a precursor polyamic acid having a repeating unit represented by the following chemical formula 4 to form a first layer; a first heating step of heating the first layer at 120°C for 20 to 60 minutes; a second heating step of heating the first layer at 180°C to 280°C for 10 minutes; and In the first layer forming step, after the underlayer heating step, the soluble porphyrin or phthalocyanine compound selected for the underlayer is added to the precursor and mixed, and the mixture is applied to form the first layer. A method for manufacturing a photoelectric conversion element. 【Chemistry 3】 【Chemistry 4】

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