All-color multiplication type organic photodetector and application thereof

Abstract

The application discloses a full-color multiplication type organic photoelectric detection device, which comprises a transparent substrate, an anode, a hole transport layer, a photosensitive layer, a spacer layer, an electron capture layer, an electron transport layer and a metal cathode in sequence; the photosensitive layer comprises an electron donor material and an electron acceptor material; the electron donor material is SnPc or PbPc; the electron acceptor material is C 60 or C 70 ; and the electron capture layer is a blended layer of MoO3 and C 60 or C 70 . The application further discloses application of the full-color multiplication type organic photoelectric detection device in preparation of a human heart rate detection device. The application utilizes a mechanism of capturing electrons to assist hole tunneling injection to prepare a high-efficiency full-color multiplication type organic photoelectric detection device, and realizes detection of a heart rate signal, and has great application potential in preparation of a human health monitoring device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic optoelectronic devices, in particular to a full-color multiplication type organic photodetector and application thereof. BACKGROUND

[0002] An organic photodetector is a sensor made of organic semiconductors, which can convert optical signals into electrical signals. Organic semiconductors have the advantages of adjustable band gap, light weight, and the ability to prepare large-area and flexible devices, so organic photodetectors have attracted widespread attention. Among them, wide-spectrum response organic photodetectors show potential applications in many emerging technical fields, such as image sensing, pulse blood oxygen sensing, optical communication, biomedical monitoring, environmental monitoring, and defense sensing, and thus have become a popular research field. To our knowledge, with the rapid development of polymer photovoltaic devices and photodetectors, a large number of high-performance near-infrared polymer materials have been developed, which has made many breakthroughs in wide-spectrum response polymer photodetectors. On the other hand, organic small-molecule materials can be used to prepare photodetectors by thermal deposition, which has the advantages of high repeatability and easy design of multi-layer structure. However, due to the lack of high-performance organic small-molecule near-infrared materials, there are few reports on small-molecule wide-spectrum response organic photodetectors. Although researchers have successfully obtained wide-spectrum response organic photodetectors using organic dyes such as phthalocyanine and squarylium, due to the limitations of light absorption efficiency, exciton generation efficiency, exciton separation efficiency, charge transport and collection efficiency, the external quantum efficiency (EQE) of these devices will not exceed 100%, which is extremely unfavorable for the detection of weak light signals. Compared with traditional photodiodes, multiplication type organic photodetectors can achieve higher EQE (more than 100%), and can detect weak light signals without additional current amplification system, showing great application potential.

[0003] Currently, some research progress has been made in small-molecule wide-spectrum multiplication type organic photodetectors. Campbell et al. demonstrated a near-infrared multiplication type organic photodetector with a gain of about 10 at a wavelength of 1000 nm under a bias voltage of-5 V (Applied Physics Letters 2009, 95(26), 263302.). However, the photosensitive layer of the device is a single layer of OSnNcCl2, so the inherent absorption characteristics of the photosensitive layer limit the light response characteristics of the device in the range of 600-800 nm. Luo et al. used C 60 The mechanism of blocking holes to assist electron tunneling injection, using PbPc:C 60For the photoactive layer, a wide-spectrum multiplication type organic photodetector with spectral response of 300-900 nm was prepared (Physica Status Solidi (RRL) 2016, 10(6), 485-492.). The peak EQE reached ~2000% at a bias of -6 V. Recently, Kublitski et al. used ZnPc:C 60 (100:3) as the photoactive layer, and combined with the mechanism of electron trapping assisted hole tunneling injection, a wide-spectrum multiplication type organic photodetector with spectral response range of 300-900 nm was prepared (Nature communications 2021, 12(1), 4259.). After optimization, the EQE of the device is close to 2000% at a bias of -10 V. Although some results have been achieved in small molecule wide-spectrum multiplication type organic photodetectors, further improvement is needed in terms of spectral response range and photodetection performance. SUMMARY

[0004] In order to overcome the above-mentioned defects and shortcomings of the prior art, the purpose of the present application is to provide a full-color multiplication type organic photodetector device, which realizes the multiplication effect by using the mechanism of MoO3 trapping photo-generated electrons to induce hole tunneling injection, thereby obtaining high external quantum efficiency (EQE>6000%).

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A full-color multiplication type organic photodetector device, comprising in sequence a transparent substrate, an anode, a hole transport layer, a photoactive layer, a spacer layer, an electron trapping layer, an electron transport layer and a metal cathode.

[0007] The photoactive layer comprises an electron donor material and an electron acceptor material; the electron donor material is SnPc or PbPc; the electron acceptor material is C 60 or C 70 .

[0008] The electron trapping layer is a blend layer of MoO3 and C 60 or C 70 .

[0009] Preferably, the photoactive layer is a blend layer of the electron donor material and the electron acceptor material.

[0010] Further preferably, the doping concentration of the electron donor material is 5wt%-80wt%.

[0011] Further preferably, the full-color multiplication type organic photodetector device further comprises an optical absorption layer arranged between the hole transport layer and the photoactive layer; the material of the optical absorption layer is SnPc or PbPc.

[0012] Preferably, the photosensitive layer comprises an electron donor layer and an electron acceptor layer which are stacked in sequence; the electron donor layer is prepared from the electron donor material; and the electron acceptor layer is prepared from the electron acceptor material.

[0013] Further preferably, the thickness of the electron donor layer is 20-100 nm; and the thickness of the electron acceptor layer is 20-100 nm.

[0014] Preferably, the material of the spacer layer is C 60 or C 70 .

[0015] Preferably, the concentration of MoO3 in the electron trapping layer is 1wt%-50wt%.

[0016] Preferably, the material of the hole transport layer is TAPC, NPB, TCTA or m-MTDATA; and the material of the electron transport layer is BCP, BmPyPb, Bphen, TmPyPb or TPBi.

[0017] Preferably, the thickness of the hole transport layer is 10-60 nm; the thickness of the light absorption layer is 0-50 nm; the thickness of the photosensitive layer is 50-200 nm; the thickness of the spacer layer is 20-80 nm; the thickness of the electron trapping layer is 5-20 nm; the thickness of the electron transport layer is 5-20 nm; and the thickness of the metal cathode is 50-200 nm.

[0018] Preferably, the transparent substrate is glass, quartz, polyethylene terephthalate (PET), polyimide (PI) or polydimethylsiloxane (PDMS).

[0019] Preferably, the anode is ITO, a conductive polymer or a metal Au (5.1eV) with a high work function.

[0020] Preferably, the material of the metal cathode is Al, Ag or Au.

[0021] Another object of the present application is to provide the use of the full-color multiplication type organic photoelectric detection device in the preparation of a human heart rate detection apparatus.

[0022] The preparation method of the full-color multiplication type organic photoelectric detection device comprises the following steps:

[0023] The transparent substrate with the anode is cleaned, and then a hole transport layer, a light absorption layer, a photosensitive layer, a spacer layer, an electron trapping layer, an electron transport layer and a metal cathode are evaporated in sequence to obtain the full-color multiplication type organic photoelectric detection device.

[0024] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0025] (1) The full-color multiplication type organic photoelectric detection device of the present application realizes multiplication effect by the mechanism of MoO3 capturing photo-generated electrons to induce hole tunneling injection, thereby obtaining high external quantum efficiency (EQE>6000%).

[0026] (2) The full-color multiplication type organic photoelectric detection device of the present application can obtain full-color multiplication type organic photoelectric detectors with bulk heterojunction structure, planar heterojunction structure and planar / bulk heterojunction structure respectively by designing the device structure.

[0027] (3) The full-color multiplication type organic photoelectric detection device of the present application with planar heterojunction structure and planar / bulk heterojunction structure, part of PbPc in the photosensitive layer forms triclinic system, thereby enhancing the response of the device in the near-infrared region.

[0028] (4) The full-color multiplication type organic photoelectric detector based on planar / bulk heterojunction structure of the present application selects a material (SubPc) with complementary absorption characteristics to the photosensitive layer (containing PbPc) as the light absorption layer, which can further compensate for the poor response of PbPc in the visible light range, thereby realizing spectral response in the wavelength range of 300-1000 nm.

[0029] (5) The full-color multiplication type organic photoelectric detection device of the present application can be used to prepare a human heart rate detection device, which has good accuracy and accuracy in heart rate testing, and shows great application potential in preparing human health monitoring devices. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The structure diagram of the full-color multiplication type organic photoelectric detection device prepared in Example 1 of the present application. In the figure, 11 is a transparent substrate, 12 is an anode, 13 is a hole transport layer, 14 is a photosensitive layer, 15 is a spacer layer, 16 is an electron trapping layer, 17 is an electron transport layer, and 18 is a metal cathode.

[0031] Figure 2 The normalized absorption spectrum curve of the photosensitive layer PbPc, C 70 , PbPc:C 70 and PbPc / C 70 thin film used in the example of the present application.

[0032] Figure 3 The working mechanism diagram of the full-color multiplication type organic photoelectric detector based on bulk heterojunction structure in Example 1 of the present application under light.

[0033] Figure 4 The external quantum efficiency curve of the full-color multiplication type organic photoelectric detector based on bulk heterojunction structure in Example 1 of the present application.

[0034] Figure 5 The structure diagram of the full-color multiplication type organic photoelectric detector prepared in Example 2 of the present application. In the diagram, 21 is a transparent substrate, 22 is an anode, 23 is a hole transport layer, 24 is an electron donor layer, 25 is an electron acceptor layer, 26 is a spacer layer, 27 is an electron trapping layer, 28 is an electron transport layer, and 29 is a metal cathode.

[0035] Figure 6 The working mechanism diagram of the full-color multiplication type organic photoelectric detector based on the planar heterojunction structure in Example 2 of the present application under light irradiation.

[0036] Figure 7 The external quantum efficiency curve diagram of the full-color multiplication type organic photoelectric detector based on the planar heterojunction structure in Example 2 of the present application.

[0037] Figure 8 The structure diagram of the full-color multiplication type organic photoelectric detector based on the planar / bulk heterojunction structure in Example 3 of the present application. In the diagram, 31 is a transparent substrate, 32 is an anode, 33 is a hole transport layer, 34 is an absorbing layer, 35 is a photosensitive layer, 36 is a spacer layer, 37 is an electron trapping layer, 38 is an electron transport layer, and 39 is a metal cathode.

[0038] Figure 9 The normalized absorption spectrum curve diagram of the PbPc and SubPc thin films in Example 3 of the present application.

[0039] Figure 10 The external quantum efficiency curve diagram of the full-color multiplication type organic photoelectric detector based on the planar / bulk heterojunction structure in Example 3 of the present application.

[0040] Figure 11 The pulse signal detection curve of the flexible full-color multiplication type organic photoelectric detector based on the planar / bulk heterojunction structure in Example 4 of the present application. DETAILED DESCRIPTION

[0041] The present application will be further described in conjunction with the examples, but the embodiments of the present application are not limited thereto.

[0042] The terms used in the present application generally have the meanings commonly understood by those of ordinary skill in the art, unless otherwise defined. The following are the full names and molecular structure formulas of the materials used in the present application:

[0043] 1. TAPC: Chinese full name 4,4'-cyclohexylbis[N,N-di(4-methylphenyl) aniline], structure as follows:

[0044]

[0045] 2. PbPc: Chinese full name lead phthalocyanine, structure as follows:

[0046]

[0047] 3、SubPc: Chinese full name of subphthalocyanine, the structure is as follows:

[0048]

[0049] 4、C 70 : Chinese full name of fullerene C 70 , the structure is as follows:

[0050]

[0051] 5、MoO3: Chinese full name of molybdenum trioxide

[0052] 6、BCP: Chinese full name of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine), the structure is as follows:

[0053]

[0054] 7、ITO Chinese full name: indium tin oxide.

[0055] In order to make the skilled in the art better understand the technical solutions of the present application, the present application will be further described in detail below in combination with examples.

[0056] In the following examples, various processes and methods not described in detail are conventional methods known in the art. The materials, reagents, devices, instruments, equipment, etc. used in the following examples, if not specifically stated, can be obtained from commercial channels.

[0057] Example 1

[0058] Full-color multiplication type organic photodetector based on bulk heterojunction structure (structure as shown in Figure 1 ), including transparent substrate 11, anode 12, hole transport layer 13, photosensitive layer 14, spacer layer 15, electron trapping layer 16, electron transport layer 17 and metal cathode 18 arranged in turn;

[0059] In this embodiment, the transparent substrate is glass; the anode is indium tin oxide (ITO); the hole transport layer is TAPC, and the thickness is 30 nm; the photosensitive layer is a blended film of electron donor material and electron acceptor material, and the thickness is 70 nm. Among them, the electron donor material is PbPc, and the electron acceptor material is C 70 , the mass concentration of the electron donor material in the photosensitive layer is 30wt%; the spacer layer material is C 70 , and the thickness is 50 nm; the electron trapping layer is C 70The blending layer with MoO3 has a thickness of 10 nm, and the doping mass concentration of MoO3 is 10 wt%; the electron transport material is BCP, and the thickness is 10 nm; and the cathode is metal aluminum, and the thickness is 100 nm.

[0060] The specific preparation method of the full-color multiplication type organic photodetector based on the body heterojunction structure is as follows:

[0061] The ITO-attached glass substrate is placed in a cleaning solution for ultrasonic cleaning for 90 minutes, rubbed and cleaned, and the surface water droplets are blown away by nitrogen. Then it is placed in a vacuum oven at 120°C for baking for 30 minutes to remove the residual moisture on the ITO glass; the dried ITO glass substrate is placed in an oxygen atmosphere with a pressure of 15 Pa, and the ionization voltage is set to 300 V, and the oxygen plasma treatment is performed for 4 minutes to further remove the residual impurities on the surface of the ITO glass. Subsequently, it is transferred into a vacuum evaporation chamber. When the vacuum degree in the vacuum evaporation chamber reaches about 10 -5 Pa, the hole transport layer, the photosensitive layer, the spacer layer, the electron trapping layer, the electron transport layer and the cathode are evaporated on the ITO electrode in sequence. The overlapping part of the two electrodes forms the effective light detection area of the device, and the effective area is 16 mm 2 . Finally, a multiplication type organic photodetector with the structure of Glass / ITO / TAPC (30 nm) / PbPc:C 70 (30 wt%, 70 nm) / C 70 (50 nm) / C 70 :MoO3 (10 nm, 10%) / BCP (10 nm) / Al (100 nm) is prepared.

[0062] Figure 2 The normalized absorption spectrum of the photosensitive material of the multiplication type organic photodetector involved in the application is shown in the figure. As can be seen from the figure, the absorption spectrum range of PbPc is 300-1000 nm, and the characteristic absorption peaks are located at 740 nm and 890 nm. 70 It has good absorption in the visible light range, and the absorption spectrum range is 300-800 nm. PbPc:C 70 The absorption spectrum range of the blended film is 300-1000 nm, and only a characteristic peak at 740 nm appears, which is because PbPc in the blended film state only forms a monoclinic system. PbPc / C 70 The absorption spectrum range of the blended film is 300-1000 nm, and only a characteristic peak at 740 nm appears, which is because PbPc in the blended film state only forms a monoclinic system. PbPc / C

[0063] Figure 3This describes the working mechanism of the multiplication-type organic photodetector involved in Example 1. When light illuminates the device, the photosensitive layer absorbs photons and generates excitons. These excitons then diffuse into PbPc:C. 70 At the interface, photogenerated electrons and holes separate. The photogenerated electrons are trapped on MoO3 in the electron-trapping layer. The accumulated electrons create a built-in electric field, causing band bending and narrowing of the potential barrier at the interface. This ultimately induces holes from the external circuit to tunnel into the device and be collected by the ITO anode. Therefore, the actual photocurrent is the sum of the photogenerated current and the hole current injected from the external circuit, ultimately exhibiting a photomultiplication effect.

[0064] Figure 4 This is a graph showing the external quantum efficiency of the multiplication organic photodetector involved in Example 1. As can be seen from the graph, the external quantum efficiency of the device increases significantly with increasing reverse bias voltage. At a bias voltage of -8V, the external quantum efficiency of the device exceeds 100% in the wavelength range of 300-1000nm, and the maximum external quantum efficiency at a wavelength of 740nm can reach 6470%.

[0065] Example 2

[0066] A panchromatic organic photodetector based on a planar heterojunction structure (structure as shown in...) Figure 5 As shown, it includes a transparent substrate 21, an anode 22, a hole transport layer 23, an electron donor layer 24, an electron acceptor layer 25, a spacer layer 26, an electron trapping layer 27, an electron transport layer 28, and a metal cathode 29 arranged sequentially.

[0067] In this embodiment, the transparent substrate is glass; the anode is indium tin oxide (ITO); the hole transport layer is TAPC with a thickness of 30 nm; and the photosensitive layer is composed of an electron donor (PbPc) and an electron acceptor (C). 70 A planar heterojunction is formed. The electron donor material PbPc has a thickness of 60 nm, and the electron acceptor material and spacer layer are both C. 70 The total thickness is 100 nm; the electron trapping layer is C 70 The blended layer with MoO3 has a thickness of 10 nm and the doping concentration of MoO3 is 10 wt%; the electron transport material is BCP with a thickness of 10 nm; the cathode is aluminum with a thickness of 100 nm.

[0068] The specific fabrication method of the panchromatic organic photodetector based on a planar heterojunction structure in this embodiment is as follows:

[0069] The ITO-coated glass substrate was cleaned in a cleaning solution for 90 minutes under ultrasonic agitation, washed by hand and blown dry with nitrogen. The ITO glass substrate was then baked in a vacuum oven at 120°C for 30 minutes to remove residual moisture from the ITO glass surface. The baked ITO glass substrate was then placed in an oxygen atmosphere at a pressure of 15 Pa and subjected to oxygen plasma treatment at an ionization voltage of 300 V for 4 minutes to further remove impurities from the ITO glass surface. The ITO glass substrate was then transferred into a vacuum evaporation chamber. When the vacuum degree in the vacuum evaporation chamber reached ~ 10 -5 Pa, a hole transport layer, an electron donor layer, an electron acceptor layer and a spacer layer, an electron trapping layer, an electron transport layer and a cathode were sequentially evaporated on the ITO electrode. The two electrodes intersected and overlapped to form an effective light detection area of the device, which had an effective area of 16 mm 2 . Finally, a multiplication-type organic photodetector having a structure of Glass / ITO / TAPC (30 nm) / PbPc (60 nm) / C 70 (100 nm) / C 70 : MoO3 (10 nm, 10%) / BCP (10 nm) / Al (100 nm) was prepared.

[0070] Figure 6 The working mechanism of the multiplication-type organic photodetector according to Example 2 is described. Like Example 1, the device according to the present example is also based on the multiplication mechanism of interface-trapped-electron-assisted-external-circuit-hole-tunneling injection. The difference is that the excitons in the present example are separated at the planar heterojunction of PbPc / C 70 , so that the exciton separation efficiency can be slightly weakened.

[0071] Figure 7 The external quantum efficiency curve of the multiplication-type organic photodetector according to Example 2 is shown in the figure. As can be seen from the figure, the spectral response range of the device is 300-1000 nm, and the external quantum efficiency in the near-infrared region is significantly improved, which is due to the planar heterojunction facilitating the formation of triclinic crystal system of PbPc. Under a bias voltage of -13 V, the maximum external quantum efficiency at a wavelength of 740 nm reached 5770%.

[0072] Example 3

[0073] A full-color multiplication-type organic photodetector based on a planar / bulk heterojunction structure (as shown in the structure of Figure 8 ), including a transparent substrate 31, an anode 32, a hole transport layer 33, a light absorption layer 34, a photosensitive layer 35, a spacer layer 36, an electron trapping layer 37, an electron transport layer 38 and a metal cathode 39 arranged in sequence.

[0074] In this embodiment, the transparent substrate is glass; the anode is indium tin oxide (ITO); the hole transport layer is TAPC, with a thickness of 30 nm; the light absorbing layer is PbPc, with a thickness of 30 nm; and the photoactive layer is a blend film of electron donor material and electron acceptor material, with a thickness of 75 nm. The electron donor material is SubPc, and the electron acceptor material is C 70 , with a mass concentration of 30 wt%; the spacer layer material is C 70 , with a thickness of 50 nm. The electron trapping layer is a blend layer of C 70 and MoO3, with a thickness of 10 nm and a doping mass concentration of MoO3 of 10 wt%; the electron transport material is BCP, with a thickness of 10 nm; and the cathode is aluminum, with a thickness of 100 nm.

[0075] The specific preparation method of the full-color multiplication type organic photodetector based on the planar / bulk heterojunction structure in this embodiment is as follows:

[0076] The ITO-attached glass substrate is placed in a cleaning solution and ultrasonically cleaned for 90 minutes, washed by hand, and the surface water droplets are blown off with nitrogen. It is then placed in a vacuum oven at 120°C and baked for 30 minutes to remove residual moisture on the ITO glass; the baked ITO glass substrate is placed in an oxygen atmosphere at a pressure of 15 Pa, and an ionization voltage of 300 V is set to perform oxygen plasma treatment for 4 minutes to further remove residual impurities on the surface of the ITO glass. Subsequently, it is transferred into a vacuum evaporation chamber. When the vacuum degree in the vacuum evaporation chamber reaches ~ 10 -5 Pa, the hole transport layer, the light absorbing layer, the photoactive layer, the spacer layer, the electron trapping layer, the electron transport layer, and the cathode are evaporated on the ITO electrode in sequence. The two electrode intersection overlapping parts form the effective light detection area of the device, with an effective area of 16 mm 2 . Finally, a multiplication type organic photodetector with the structure Glass / ITO / TAPC (30 nm) / PbPc (50 nm) / PbPc:C 70 (30 wt%, 75 nm) / C 70 (50 nm) / C 70 :MoO3 (10 nm, 10%) / BCP (10 nm) / Al (100 nm) is obtained.

[0077] Figure 9Normalized absorption spectrum of the photosensitive material of the multiplication type organic photodetector involved in Example 3. As can be seen from the figure, the absorption spectrum of PbPc ranges from 300 to 1000 nm, and the characteristic absorption peaks are located at 740 nm and 890 nm. The characteristic absorption peak of SubPc is located at 585 nm, and the strong absorption position thereof has absorption complementary characteristics with PbPc, and can well make up for the deficiency of weak response of PbPc in the visible light part.

[0078] Figure 10 The external quantum efficiency curve of the multiplication type organic photodetector involved in Example 3. As can be seen from the figure, due to the use of the planar / bulk heterojunction structure and the selection of the active material with absorption complementary characteristics, the response of the device in the range of 300-1000 nm is relatively flat. With the increase of the reverse applied voltage, the external quantum efficiency of the device is significantly improved. At a bias voltage of-8 V, the external quantum efficiency of the device in the wavelength range of 300-1000 nm is greater than 1000%, and the EQE in the near-infrared region at a wavelength of 890 nm can also exceed 6000%, which is obviously higher than the reported small molecule multiplication type organic photodetectors of the same type.

[0079] Example 4

[0080] The flexible full-color multiplication type organic photodetector based on the planar / bulk heterojunction structure comprises a transparent flexible substrate, an anode, a hole transport layer, an absorption layer, a photosensitive layer, a spacer layer, an electron trapping layer, an electron transport layer and a metal cathode which are sequentially arranged.

[0081] In this embodiment, the transparent flexible substrate is PET; the anode is indium tin oxide (ITO); the hole transport layer is TAPC, and the thickness thereof is 30 nm; the absorption layer is PbPc, and the thickness thereof is 30 nm; and the photosensitive layer is a blended film of an electron donor material and an electron acceptor material, and the thickness thereof is 75 nm. The electron donor material is SubPc, and the electron acceptor material is C 70 The mass concentration of the electron donor material in the photosensitive layer is 30wt%; the spacer layer material is C 70 , and the thickness thereof is 50 nm. The electron trapping layer is a blended layer of C 70 and MoO3, and the thickness thereof is 10 nm, and the doping mass concentration of MoO3 is 10wt%; the electron transport material is BCP, and the thickness thereof is 10 nm; and the cathode is metal aluminum, and the thickness thereof is 100 nm.

[0082] The specific preparation method of the flexible full-color multiplication type organic photodetector based on the planar / bulk heterojunction structure in this embodiment is as follows:

[0083] The ITO-attached PET substrate was ultrasonically cleaned in a cleaning solution for 90 minutes, gently rubbed and the surface water beads were blown off with nitrogen. Then it was baked in a vacuum oven at 90°C for 60 minutes to remove the residual water on the ITO glass; the dried ITO glass substrate was placed in an oxygen atmosphere at a pressure of 15 Pa, and an ionization voltage of 300 V was set to perform oxygen plasma treatment for 4 minutes to further remove the residual impurities on the surface of the ITO glass. Subsequently, it was transferred into a vacuum evaporation chamber. When the vacuum degree in the vacuum evaporation chamber reached ~ 10 -5 Pa, a hole transport layer, an absorbing layer, a photosensitive layer, a spacer layer, an electron trapping layer, an electron transport layer, and a cathode were sequentially evaporated on the ITO electrode. The effective light detection area of the device was formed by the overlapping part of the two electrodes, and the effective area was 16 mm 2 . Finally, a multiplication type organic photodetector with the structure of PET / ITO / TAPC (30 nm) / PbPc (30 nm) / SubPc:C 70 (30 wt%, 75 nm) / C 70 (50 nm) / C 70 :MoO3 (10 nm, 10%) / BCP (10 nm) / Al (100 nm) was prepared.

[0084] The heart rate signal detection principle of the flexible multiplication type organic photodetector involved in Example 4 is as follows: when a beam of light passes through the human body, it is absorbed by the skin, bones, muscles, tissues, and blood of the human body. The arterial blood in the blood pulsates periodically with the heartbeat, which causes the absorption of light by the blood to also change periodically. The transmitted light signal is detected by a photodetector, and the heart rate of the human body can be calculated according to the number of pulses in the test time. Since long-wavelength light is more conducive to penetrating the human body, red light (633 nm) and near-infrared light (909 nm) LEDs were used as incident light sources in this embodiment, the flexible multiplication type organic photodetector in Example 4 was used as a light signal detection device, and a relatively thin fingertip was selected as a test site to detect the heart rate of the human body.

[0085] Figure 11The heart rate signal detection map of the flexible multiplication type organic photodetector involved in Example 4. As can be seen from the figure, the curves based on red light and near-infrared light test both show excellent periodic characteristics. Under the same conditions, the signal of the near-infrared light test is obviously higher than that of the red light test, because the near-infrared light has stronger penetration, so as to ensure more light to penetrate the finger and be detected by the detector. The heart rate at rest and after exercise can be calculated by the number of cycles within the test time, which is 87 times / minute and 116 times / minute respectively. The results show good consistency with the results measured by the commercial finger clip pulse oximeter, which shows that the device of the present embodiment has good accuracy and accuracy in heart rate test, and shows its great application potential in human health monitoring.

[0086] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A panchromatic multiplication type organic photodetector, characterized in that, It consists of, in sequence, a transparent substrate, an anode, a hole transport layer, a light-absorbing layer, a photosensitive layer, a spacer layer, an electron trapping layer, an electron transport layer, and a metal cathode; The light-absorbing layer is PbPc; The photosensitive layer is a blended thin film of an electron donor material and an electron acceptor material; the concentration of the electron donor material is 30 wt%; the electron donor material is SubPc, and the electron acceptor material is C. 70 ; The thickness of the light-absorbing layer is 30 nm; the thickness of the photosensitive layer is 75 nm. The full-color multiplication organic photodetector has a planar / bulk heterojunction structure; The electron trapping layer is composed of MoO3 and C. 60 Or C 70 Blend layer; At a bias voltage of -8 V, the external quantum efficiency of the full-color multiplication organic photodetector is greater than 1000% in the wavelength range of 300-1000 nm.

2. The panchromatic multiplication organic photodetector device according to claim 1, characterized in that, The material of the spacer layer is C. 60 Or C 70 .

3. The panchromatic multiplication organic photodetector device according to claim 1, characterized in that, The concentration of MoO3 in the electron trapping layer is 1wt%~10wt%.

4. The panchromatic multiplication organic photodetector device according to claim 1, characterized in that, The hole transport layer is made of TAPC, NPB, TCTA, or m-MTDATA; the electron transport layer is made of BCP, BmPyPb, Bphen, TmPyPb, or TPBi.

5. The application of the full-color multiplication organic photodetector as described in any one of claims 1 to 4 in the preparation of a human heart rate detection device.

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