Visual optical signal detection device and equipment based on optical regeneration gain mechanism

Abstract

The invention discloses a visual optical signal detection device and equipment based on an optical regeneration gain mechanism. The visual optical signal detection device sequentially comprises a transparent substrate, a transparent anode, an optical detection unit, at least one light-emitting unit, an electron injection layer and a cathode. The optical detection unit sequentially comprises a hole barrier layer, a first electron transport layer and an optical active layer; the optical active layer is formed by blending TAPC and fullerene; the fullerene is C60 or C70; the light-emitting unit sequentially comprises a hole transport layer, a light-emitting layer and a second electron transport layer; the light-emitting layer takes an exciplex as a host and a phosphorescent material as an object. The light current at the anode is gained, the detection sensitivity is high, detection of weak light signals is facilitated, the image of the light source is directly imaged on the device, and simplification of the structure of detection equipment is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of optical signal detection, and particularly to a visual optical signal detection device and equipment based on an optical regeneration gain mechanism. Background Art

[0002] As a core component of optoelectronic technology, photodetectors play an important role in fields such as communication, sensing, imaging, and energy. However, despite the significant progress made in photodetection technology in recent years, existing detectors still face many challenges and limitations in practical applications. For example, low sensitivity affects the detection performance in low-light environments. Multiplication photodetectors (such as photomultiplier tubes and avalanche photodiodes) have been widely used in fields such as low-light detection, single-photon detection, and high-precision measurement due to their high sensitivity and internal gain characteristics. However, despite the significant advantages of such detectors in performance, they still have some drawbacks that need to be solved urgently in practical applications. First, multiplication photodetectors are usually accompanied by a relatively high noise level, especially dark current and excess noise, which limits their performance in low signal-to-noise ratio environments. Second, although their response speed is relatively fast, they may still be limited by the gain-bandwidth product in ultra-high-frequency applications. At the same time, such detectors are large in size and high in power consumption, making it difficult to meet the requirements of modern miniaturized and low-power devices. Finally, the manufacturing cost of multiplication photodetectors is relatively high, and they are prone to gain saturation or damage under high light intensity conditions, limiting their dynamic range and service life. In addition, existing photodetectors cannot directly display the light source image on the device. The main reason lies in the limitations of their core functions and physical mechanisms: as unidirectional optoelectronic conversion devices, detectors can only convert optical signals into electrical signals, lacking active light-emitting components (such as pixelated light-emitting units) and opto-electro-optic bidirectional conversion capabilities, resulting in their inability to generate visible light images independently. More importantly, their output signals are analog or digital electrical signals, and image reconstruction must rely on external processing circuits and display devices (such as screens), with limited real-time performance and integration. At the same time, problems such as insufficient dynamic range, noise interference, and temperature sensitivity will further reduce the quality of the output signal, indirectly affecting the accuracy and clarity of the final image. Therefore, conducting in-depth research on these drawbacks and exploring new materials, structures, mechanisms, and processes are of great significance for further improving the performance of multiplication photodetectors and realizing visualization. Summary of the Invention

[0003] In order to overcome the above-mentioned disadvantages and deficiencies of the prior art, the purpose of the present invention is to provide a visualization optical signal detection device based on an optical regeneration gain mechanism. Under the continuous illumination of the light source to be measured, optical regeneration phenomena occur cyclically in the device, and the self-generated photocurrent continuously increases, enabling the photocurrent at the anode to be gain, while having a low dark current and high detection sensitivity, which is beneficial to the detection of weak optical signals. Moreover, no additional display unit is required, and the image of the light source is directly imaged on the visualization optical signal detection device based on the optical regeneration gain mechanism, which is beneficial to the simplification of the detection device structure.

[0004] Another purpose of the present invention is to provide a visualization optical signal detection device based on an optical regeneration gain mechanism, which can achieve visualization without an additional display unit and has a simple device structure.

[0005] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a visualization optical signal detection device based on an optical regeneration gain mechanism, which sequentially includes a transparent substrate, a transparent anode, a light detection unit, at least one light-emitting unit, an electron injection layer, and a cathode; The light detection unit sequentially includes a hole blocking layer, a first electron transport layer, and a photoactive layer; the photoactive layer is composed of a blend of TAPC (the full Chinese name is 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]) and fullerene; the fullerene is C 60 (the full Chinese name is fullerene C 60 ) or C 70 (the full Chinese name is fullerene C 70 ); The light-emitting unit sequentially includes a hole transport layer, a light-emitting layer, and a second electron transport layer; the light-emitting layer is based on an exciplex as the host and a phosphorescent material as the guest; When the visualization optical signal detection device works, under the illumination of the light source to be measured and the action of a forward bias voltage, the photoactive layer absorbs incident photons and generates photo-generated electrons and photo-generated holes; the photo-generated electrons drift to the anode to form an incident photocurrent, and the photo-generated holes drift to the light-emitting layer and recombine with the electrons injected from the cathode to generate self-generated photons; a part of the self-generated photons exit from the transparent substrate and form an image of the light source on the visualization optical signal detection device; another part of the self-generated photons are absorbed by the photoactive layer and undergo optical regeneration: the photoactive layer absorbs the self-generated photons to generate self-generated photo-generated electrons and self-generated photo-generated holes, the self-generated photo-generated electrons form a self-generated photocurrent at the anode, and the self-generated photo-generated holes drift to the light-emitting layer and recombine with the electrons injected from the cathode to generate new self-generated photons; under the continuous illumination of the light source to be measured, the photoactive layer continuously absorbs incident photons to drive the light-emitting layer to generate self-generated photons, optical regeneration continuously occurs, the number of self-generated photons continuously increases, and the self-generated photocurrent continuously increases, realizing photocurrent gain.

[0006] Preferably, in the photoactive layer, the mass concentration of TAPC is 5 wt% to 50 wt%; the thickness of the photoactive layer is 50 to 200 nm.

[0007] Preferably, the exciplex is formed by blending mCBP (full Chinese name: 3,3'-bis(N-carbazolyl)-1,1'-biphenyl) and PO-T2T (full Chinese name: 2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine) in a mass ratio of 1:(0.8 to 1.2).

[0008] Preferably, the phosphorescent material is FIrpic (full Chinese name: iridium bis(4,6-difluorophenylpyridine-N,C2)picolinate); in the light-emitting layer, the mass concentration of the phosphorescent material is 6% to 30%.

[0009] Preferably, the hole-blocking layer is ZnO (full Chinese name: zinc oxide) or BCP (full Chinese name: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), and the thickness is 10 to 50 nm.

[0010] Preferably, the hole-transporting layer has a three-layer structure to reduce charge loss, specifically including a TAPC layer, a TCTA (full Chinese name: tris(4-carbazol-9-ylphenyl)amine) layer, and an mCBP layer; more preferably, the thickness of the TAPC layer is 5 to 60 nm, the thickness of the TCTA layer is 3 to 10 nm; the thickness of the mCBP layer is 3 to 10 nm.

[0011] Preferably, when there are two or more light-emitting units, a connection layer is provided between the light-emitting units; more preferably, the connection layer includes a Liq (full Chinese name: lithium 8-hydroxyquinoline) layer with a thickness of 1.5 to 2.5 nm; an Al layer with a thickness of 0.5 to 1.5 nm and a HAT-CN (full Chinese name: 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene) layer with a thickness of 5 to 20 nm.

[0012] Preferably, the transparent substrate is glass, quartz, polyethylene terephthalate (PET), or polyimide (PI).

[0013] Preferably, the material of the first electron-transporting layer is C 60 or C 70 ; the thickness is 10 to 30 nm.

[0014] Preferably, the material of the second electron-transporting layer is PO-T2T, BmPyPb, Bphen, TmPyPb, or TPBi; the thickness is 40 to 80 nm.

[0015] Preferably, the material of the electron injection layer is Liq; the thickness is 1.5 - 2.5 nm.

[0016] The present invention also provides a visualization optical signal detection device based on the optical regeneration gain mechanism, including a DC power supply, a current measurement unit, and the visualization optical signal detection device based on the optical regeneration gain mechanism; the current measurement unit is used to measure the photocurrent at the transparent anode.

[0017] The principle of the present invention is as follows: Under the illumination of the light source to be measured and the applied bias voltage, the visualization optical signal detection device of the present invention based on the optical regeneration gain mechanism generates excitons after the photoactive layer absorbs incident photons. The excitons are separated into incident photo-generated electrons and incident photo-generated holes. The incident photo-generated electrons drift to the anode and are collected to form a photocurrent, and this part of the current can be called the incident photocurrent; while the incident photo-generated holes drift to the light-emitting layer and recombine with the electrons injected from the cathode to generate new photons, and these photons are called self-generated photons. Like the incident photons, the self-generated photons are also absorbed by the photoactive layer, and the generated self-generated photo-generated electrons will form an additional photocurrent, called the self-generated photocurrent; the self-generated photo-generated holes drift to the light-emitting layer and recombine with the electrons injected from the cathode to generate new self-generated photons, and this process is called optical regeneration. Obviously, the optical regeneration process will occur cyclically. Under the continuous illumination of the light source to be measured, the photoactive layer will continuously absorb incident photons to drive the light-emitting layer to generate more self-generated photons, which makes the number of self-generated photons increase continuously. However, since the photo-electric conversion efficiency in the device and the absorption rate of the self-generated photons by the active layer cannot reach 100%, the increasing rate of the self-generated photons will decrease with the increase of time, which also means that there is a maximum value for the number of self-generated photons. When the number of self-generated photons reaches the maximum value, the device reaches a steady state, and the total photocurrent is the sum of the incident photocurrent generated by the photoactive layer absorbing incident photons and the self-generated photocurrent generated by the self-generated photons, and finally shows a large photocurrent gain. At the same time, under the illumination condition and the applied bias voltage, since the photoactive layer cannot completely absorb the self-generated photons generated by the light-emitting unit, a part of the self-generated photons are emitted from the anode. At the same time, in a dark environment, the ultra-low dark current of the device is not enough to drive the light-emitting unit to emit light. When a light source with a certain shape irradiates the device, the irradiated area can drive the light-emitting unit to generate self-generated photons, while the area not irradiated by light will not generate photons, so that an image of the light source can be formed on the surface of the device, and the shape of the light source can be directly observed. When designing the photoactive layer of the present invention, it is necessary to balance the ratio of the absorbed photons to the photons that are not absorbed and emitted from the anode, which not only needs to ensure the gain of the photocurrent, but also needs to ensure that the light source image has sufficient intensity, and this can be achieved by selecting specific materials and specific thicknesses. The gain of the photocurrent and the intensity of the light source image can also be regulated by the number of light-emitting units, the material of the light-emitting layer, the thickness of the light-emitting layer, etc.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) For the visual optical signal detection device based on the optical regeneration gain mechanism of the present invention, the photo-electrons collected by the anode include the incident photo-electrons generated by the incident light in the photo-active layer, and also include a part of the self-generated photo-electrons generated by optical regeneration, realizing the gain of photocurrent, and being particularly suitable for the detection of weak light sources; another part of the self-generated photo-electrons generated by the light-emitting layer are emitted from the anode, forming an image of the light source on the device, and realizing visualization without an additional display screen.

[0019] (2) For the visual optical signal detection device based on the optical regeneration gain mechanism of the present invention, through the design of the device, especially the material selection and thickness design of the photo-active layer and the design of the light-emitting unit, the gain of photocurrent is realized, thereby improving the detection sensitivity, and at the same time, the visual detection of the light source is realized.

[0020] (3) For the visual optical signal detection device based on the optical regeneration gain mechanism of the present invention, the gain of the photocurrent in the device does not need to rely on the tunneling injection of external charges. Through the design of the hole blocking layer and the hole transport layer (which has a blocking effect on electrons), the injection of external charges can be hindered, thereby reducing the dark current of the device and improving the detection sensitivity.

[0021] (4) For the visual optical signal detection device based on the optical regeneration gain mechanism of the present invention, an image of the light source can be formed on the device, without an additional display screen, which is beneficial to simplifying the device structure and realizing the miniaturization of the device. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the visual optical signal detection device based on the optical regeneration gain mechanism of the embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the working mechanism of the visual optical signal detection device based on the optical regeneration gain mechanism of the embodiment of the present invention.

[0024] Figure 3 It is the normalized absorption spectrum of the photo-active layer of the visual optical signal detection device based on the optical regeneration gain mechanism of Embodiment 1 of the present invention.

[0025] Figure 4 It is the electroluminescence spectrum of the light-emitting layer in the visual optical signal detection device based on the optical regeneration gain mechanism of Embodiment 1 of the present invention.

[0026] Figure 5 It is the external quantum efficiency curve graph of the visual optical signal detection device based on the optical regeneration gain mechanism of Embodiment 1 of the present invention.

[0027] Figure 6Dark current curve of the visual optical signal detection device based on the optical regeneration gain mechanism in Embodiment 1 of the present invention.

[0028] Figure 7 In (a) and (b) are the normalized transient photocurrent response (J-t curve) and electroluminescence (EL) characteristic curve of the visual optical signal detection device based on the optical regeneration gain mechanism in the embodiment of the present invention under the illumination of an LED with a pulse frequency of 100 Hz and a peak value of 535 nm.

[0029] Figure 8 Is Figure 7 Characteristic diagram of the direct relationship between the transient photocurrent and the electroluminescence intensity in

[0030] Figure 9 Normalized absorption spectrum of the photoactive layer of the visual optical signal detection device based on the optical regeneration gain mechanism in Embodiment 2 of the present invention.

[0031] Figure 10 External quantum efficiency curve of the visual optical signal detection device based on the optical regeneration gain mechanism in Embodiment 2 of the present invention.

[0032] Figure 11 Dark current curve of the visual optical signal detection device based on the optical regeneration gain mechanism in Embodiment 2 of the present invention.

[0033] Figure 12 Is the image of the light source displayed on the device surface when detecting a light source with the word "SCUT" using the visual optical signal detection device based on the optical regeneration gain mechanism in Embodiment 2 of the present invention.

[0034] Figure 13 In (a) - (d) are the images of the light source displayed on the device surface when detecting one, two, three, and four circular light sources using the visual optical signal detection device based on the optical regeneration gain mechanism in Embodiment 2 of the present invention.

[0035] Figure 14 Is Figure 13 Relationship curve between the photocurrent and the number of circular light sources in Detailed implementation

[0036] The following combines the embodiments to further elaborate on the present invention in detail, but the implementation manners of the present invention are not limited thereto.

[0037] Full names and molecular structural formulas of some materials used in the present invention: 1. TAPC: Chinese full name 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], the structure is as follows:

[0038] 2. C 60 : Chinese full name: Fullerene C 60 , the structure is as follows:

[0039] 3. C 70 : Chinese full name: Fullerene C 70 , the structure is as follows:

[0040] 4. TCTA: Chinese full name: Tris(4-carbazol-9-ylphenyl)amine, the structure is as follows:

[0041] 5. mCBP: Chinese full name: 3,3'-Di(N-carbazolyl)-1,1'-biphenyl, the structure is as follows:

[0042] 5. PO-T2T: Chinese full name: 2,4,6-Tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine, the structure is as follows:

[0043] 6. FIrpic: Chinese full name: Iridium(III) bis(4,6-difluorophenylpyridinato-N,C2)picolinate, the structure is as follows:

[0044] 7. Liq: Chinese full name: Lithium 8-hydroxyquinoline, the structure is as follows:

[0045] 8. HAT-CN: Chinese full name: 2,3,6,7,10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene, the structure is as follows:

[0046] 9. BCP: Chinese full name: 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline, the structure is as follows:

[0047] 10. ZnO: Chinese full name: Zinc oxide.

[0048] 11. ITO: Chinese full name: Indium tin oxide.

[0049] Example 1 The structural schematic diagram of the visual optical signal detection device based on the optical regeneration gain mechanism in this example is asFigure 1 As shown, from bottom to top, it sequentially includes a transparent substrate 1, an anode 2, a hole blocking layer 3, an electron transport layer 4, a photoactive layer 5, a hole transport layer 6, a light-emitting layer 7, an electron transport layer 8, a connection layer 9, a hole transport layer 10, a light-emitting layer 11, an electron transport layer 12, an electron injection layer 13, and a metal cathode 14. Among them, the hole blocking layer 3, the electron transport layer 4, and the photoactive layer 5 constitute a photodetection unit, the hole transport layer 6, the light-emitting layer 7, and the electron transport layer 8 constitute a first light-emitting unit, and the hole transport layer 10, the light-emitting layer 11, and the electron transport layer 12 constitute a second light-emitting unit.

[0050] In this embodiment, the transparent substrate 1 is glass; the anode 2 is indium tin oxide (ITO); the hole blocking layer 3 is BCP, and its thickness is 16 nm; the material of the electron transport layer 4 is C 60 , and its thickness is 30 nm; the photoactive layer 5 is a blend film of an electron donor material and an electron acceptor material, and its thickness is 200 nm. Among them, the electron donor material is TAPC, and the electron acceptor material is C 60 , and the mass concentration of the electron donor material in the photoactive layer 5 is 30 wt%; the hole transport layer 6 is a three-layer structure composed of a TAPC layer, a TCTA layer, and an mCBP layer; the thickness of the TAPC layer is 40 nm; the thicknesses of the TCTA layer and the mCBP layer are both 5 nm; the light-emitting layer 7 has an exciplex as the main body and a blue phosphorescent material FIrpic as the guest, and its thickness is 30 nm; the exciplex is formed by blending the electron donor material mCBP and the electron acceptor material PO-T2T; the mass concentration ratio of the electron donor material, the electron acceptor material, and the blue phosphorescent material in the light-emitting layer 7 is 1:1:0.15; the material of the electron transport layer 8 is PO-T2T, and its thickness is 55 nm; the connection layer 9 includes a Liq layer, an Al layer l, and a HAT-CN layer, where the thickness of the Liq layer is 1.5 nm, the thickness of the Al layer is 1 nm, and the thickness of the HAT-CN layer is 10 nm; the hole transport layer 10 is a three-layer structure composed of a TAPC layer, a TCTA layer, and an mCBP layer, where the thickness of the TAPC layer is 40 nm, and the thicknesses of the TCTA layer and the mCBP layer are both 5 nm; the light-emitting layer 11 has an exciplex as the main body and the blue phosphorescent material FIrpic as the guest, and its thickness is 30 nm; the exciplex is formed by blending the electron donor material mCBP and the electron acceptor material PO-T2T; the mass concentration ratio of the electron donor material, the electron acceptor material, and the blue phosphorescent material in the light-emitting layer 11 is 1:1:0.15; the material of the electron transport layer 12 is PO-T2T, and its thickness is 55 nm; the material of the electron injection layer 13 is Liq, and its thickness is 1.5 nm; the cathode 14 is metal aluminum, and its thickness is 100 nm.

[0051] The specific preparation method of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment is as follows: After the glass substrate with the ITO anode is ultrasonically cleaned in the washing solution for 90 minutes, it is washed with deionized water and dried with nitrogen, and then placed in a true oven at 120 °C for baking for 30 minutes; the dried ITO glass is treated with oxygen plasma for 4 minutes to further remove the impurities remaining on the ITO surface, and then it is transferred into the vacuum evaporation system. When the vacuum degree in the vacuum evaporation system reaches ~10 -5 Pa, a hole blocking layer 3, an electron transport layer 4, a photoactive layer 5, a hole transport layer 6, a light-emitting layer 7, an electron transport layer 8, a connection layer 9, a hole transport layer 10, a light-emitting layer 11, an electron transport layer 12, an electron injection layer 13, and a metal cathode 14 are sequentially evaporated on the anode 2. Among them, the device is composed of the overlapping part of two electrodes, and its effective area is 20 mm 2 . Finally, a device with the structure of Glass / ITO / BCP(16nm) / C 60 (30nm) / TAPC:C 60 (30%,200nm) / TAPC(40nm) / TCTA(5nm) / mCBP(5nm) / mCBP:PO-T2T:FIrpic(1:1:0.15,30nm) / PO-T2T(55nm) / Liq(1.5nm) / Al(1nm) / HATCN(10nm) / TAPC(40nm) / TCTA(5nm) / mCBP(5nm) / mCBP:PO-T2T:FIrpic(1:1:0.15,30nm) / PO-T2T(55nm) / Liq(1.5nm) / Al(100nm) is prepared.

[0052] Figure 2Schematic diagram of the working mechanism of the visual optical signal detection device based on the optical regeneration gain mechanism of the embodiments of the present invention. The specific process is as follows: Under illumination and the application of a bias voltage, excitons are generated after the photoactive layer absorbs incident photons, and the excitons are separated into incident photo-generated electrons and incident photo-generated holes. The incident photo-generated electrons drift to the anode and are collected to form a photocurrent, and this part of the current can be called the incident photocurrent; while the incident photo-generated holes drift to the light-emitting layer and recombine with the electrons injected from the cathode to generate new photons, and these photons are called self-generated photons. Like the incident photons, the self-generated photons are also absorbed by the photoactive layer, and the generated self-generated photo-generated electrons will form an additional photocurrent, called the self-generated photocurrent; the self-generated photo-generated holes also drift into the light-emitting layer and recombine with the electrons injected from the cathode to generate new self-generated photons, and this process is called optical regeneration. Obviously, the optical regeneration process will occur cyclically. Under continuous illumination, the photoactive layer will continuously absorb incident photons to drive the light-emitting layer to generate more self-generated photons, which makes the number of self-generated photons increase continuously. However, since the optoelectronic conversion efficiency in the device and the absorption rate of the self-generated photons by the active layer cannot reach 100%, the increase rate of the self-generated photons will decrease with the passage of time, which also means that there is a maximum value for the number of self-generated photons. When the number of self-generated photons reaches the maximum value, the device reaches a steady state, and the total photocurrent is the sum of the incident photocurrent generated by the photoactive layer absorbing incident photons and the self-generated photocurrent generated by the self-generated photons, and finally shows a large photocurrent gain.

[0053] Meanwhile, under the illumination condition and the applied external bias voltage, since the photoactive layer cannot completely absorb the self-generated photons generated by the light-emitting unit, a part of the self-generated photons exit from the anode. At the same time, in a dark environment, the ultra-low dark current of the device is not sufficient to drive the light-emitting unit to emit light. When a light source with a certain shape irradiates the device, the irradiated area can drive the light-emitting unit to generate self-generated photons, while the area not irradiated by light will not generate photons, so that an image of the light source can be formed on the surface of the device, and the shape of the light source can be directly observed.

[0054] Figure 3 Normalized absorption spectrum of the photoactive layer in the visual optical signal detection device based on the optical regeneration gain mechanism of this embodiment. As can be seen from the figure, the absorption spectrum range of TAPC is 300 - 400 nm; C 60 has good absorption in the visible light range, and the main absorption spectrum range is 300 - 550 nm; TAPC:C 60 The main absorption spectrum range of the blend film is 300 - 500 nm.

[0055] Figure 4This is the electroluminescence spectrum of the light-emitting layer in the visualization optical signal detection device based on the optical regeneration gain mechanism of this embodiment. It can be seen from the figure that the emission spectrum range of the mCBP:PO-T2T:FIrpic blend film is 450 - 600 nm, and the peak is at 490 nm, which also indicates that the self-generated photons generated by the light-emitting layer can be absorbed by the photoactive layer.

[0056] Figure 5 This is the external quantum efficiency curve graph of the visualization optical signal detection device based on the optical regeneration gain mechanism of this embodiment. It can be seen from the figure that as the positive external bias voltage increases, the external quantum efficiency of the device continuously improves. At a bias voltage of 13 V, the maximum external quantum efficiency at a wavelength of 440 nm can reach 130%.

[0057] Figure 6 This is the dark current curve graph of the visualization optical signal detection device based on the optical regeneration gain mechanism of this embodiment. At a bias voltage of 13 V, the device still maintains an ultra-low dark current of 5×10 -8 Acm -2 . The above test results show that the visualization optical signal detection device based on the optical regeneration gain mechanism of this embodiment has high sensitivity when used for detecting weak signals.

[0058] Figure 7 In (a) and (b) are the normalized transient photocurrent response (J-t curve) and electroluminescence (EL) characteristic curve graphs of the visualization optical signal detection device based on the optical regeneration gain mechanism of this embodiment under the irradiation of an LED with a pulse frequency of 100 Hz and a peak of 535 nm. It can be seen that the growth trajectory of the photocurrent can be clearly divided into two stages: in the first stage, the transient photocurrent of the device rises rapidly (as shown within the dotted circle in (a) below), and this part of the photocurrent is generated after the active layer absorbs the incident photons. At the same time, the EL intensity is almost zero, which confirms that there are no self-generated photons in the light-emitting layer yet; in the second stage, the EL intensity begins to rise, which also indicates the formation of self-generated photons. At the same time, the transient photocurrent begins to rise, and the rising rate is almost the same as the rising rate of the EL intensity, which confirms that the active layer absorbs self-generated photons to generate additional photocurrent, realizing the gain of photocurrent in the device. Figure 7 In (a) and (b) are the normalized transient photocurrent response (J-t curve) and electroluminescence (EL) characteristic curve graphs of the visualization optical signal detection device based on the optical regeneration gain mechanism of this embodiment under the irradiation of an LED with a pulse frequency of 100 Hz and a peak of 535 nm. It can be seen that the growth trajectory of the photocurrent can be clearly divided into two stages: in the first stage, the transient photocurrent of the device rises rapidly (as shown within the dotted circle in (a) below), and this part of the photocurrent is generated after the active layer absorbs the incident photons. At the same time, the EL intensity is almost zero, which confirms that there are no self-generated photons in the light-emitting layer yet; in the second stage, the EL intensity begins to rise, which also indicates the formation of self-generated photons. At the same time, the transient photocurrent begins to rise, and the rising rate is almost the same as the rising rate of the EL intensity, which confirms that the active layer absorbs self-generated photons to generate additional photocurrent, realizing the gain of photocurrent in the device.

[0059] Figure 8 is Figure 7 The direct relationship characteristic graph between the transient photocurrent and the electroluminescence intensity in. It can be clearly seen that when the electroluminescence intensity is close to zero, the transient photocurrent rises rapidly. As the optical regeneration process starts, the electroluminescence intensity begins to increase. More importantly, the mutual conversion relationship between the transient photocurrent and the self-generated photons is linearly fitted for the latter half of the curve, confirming the existence of the optical regeneration process.

[0060] The visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment can be assembled with a DC power supply and a current measurement unit into a visual optical signal detection device based on the optical regeneration gain mechanism. The current measurement unit is used to measure and display the photocurrent at the transparent anode. During the detection work, the magnitude of the photocurrent can reflect to a certain extent the distance between the device and the light source, which is beneficial to quickly finding the light source; the DC power supply is connected to the anode of the visual optical signal detection device based on the optical regeneration gain mechanism to provide the working voltage.

[0061] In this embodiment, under the continuous illumination of the light source to be measured, the optical regeneration phenomenon occurs cyclically in the device, and the self-generated photocurrent continuously increases, so that the photocurrent at the anode is amplified. At the same time, the dark current is low and the detection sensitivity is high, which is beneficial to the detection of weak optical signals. And no additional display unit is required, and the image of the light source is directly imaged on the visual optical signal detection device based on the optical regeneration gain mechanism, which is beneficial to the simplification of the detection device structure.

[0062] Embodiment 2 The structure of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment is the same as that in Embodiment 1, and reference can be made to Figure 1 , which successively includes a transparent substrate 1, an anode 2, a hole blocking layer 3, an electron transport layer 4, a photoactive layer 5, a hole transport layer 6, a light-emitting layer 7, an electron transport layer 8, a connection layer 9, a hole transport layer 10, a light-emitting layer 11, an electron transport layer 12, an electron injection layer 13, and a metal cathode 14; among them, the hole blocking layer 3, the electron transport layer 4, and the photoactive layer 5 constitute a light detection unit, and the hole transport layer 6, the light-emitting layer 7, and the electron transport layer 8 constitute a first light-emitting unit, and the hole transport layer 10, the light-emitting layer 11, and the electron transport layer 12 constitute a second light-emitting unit.

[0063] In this embodiment, the transparent substrate 1 is glass; the anode 2 is indium tin oxide (ITO); the hole blocking layer 3 is ZnO with a thickness of 35 nm; the material of the electron transport layer 4 is C 60 , with a thickness of 30 nm; the photoactive layer 5 is a blend film of an electron donor material and an electron acceptor material, with a thickness of 200 nm. Among them, the electron donor material is TAPC, and the electron acceptor material is C 70, the mass concentration of the electron donor material in the photoactive layer 5 is 15 wt%; the hole transport layer 6 is a three-layer structure composed of a TAPC layer, a TCTA layer, and an mCBP layer; the thickness of the TAPC layer is 10 nm; the thicknesses of the TCTA layer and the mCBP layer are both 5 nm; the light-emitting layer 7 has an exciplex as the host and a blue phosphorescent material FIrpic as the guest, with a thickness of 30 nm; the exciplex is formed by blending the electron donor material mCBP and the electron acceptor material PO-T2T; the mass concentration ratio of the electron donor material, the electron acceptor material, and the blue phosphorescent material in the light-emitting layer 7 is 1:1:0.15; the material of the electron transport layer 8 is PO-T2T, with a thickness of 35 nm; the connection layer 9 includes a Liq layer, an Al layer, and a HAT-CN layer, where the thickness of the Liq layer is 1.5 nm, the thickness of the Al layer is 1 nm, and the thickness of the HAT-CN layer is 10 nm; the hole transport layer 10 is a three-layer structure composed of a TAPC layer, a TCTA layer, and an mCBP layer, and the thicknesses of the TAPC layer, the TCTA layer, and the mCBP layer are all 5 nm; the light-emitting layer 11 has an exciplex as the host and the blue phosphorescent material FIrpic as the guest, with a thickness of 30 nm; the exciplex is formed by blending the electron donor material mCBP and the electron acceptor material PO-T2T; the mass concentration ratio of the electron donor material, the electron acceptor material, and the blue phosphorescent material in the light-emitting layer 11 is 1:1:0.15; the material of the electron transport layer 12 is PO-T2T, with a thickness of 35 nm; the material of the electron injection layer 13 is Liq, with a thickness of 1.5 nm; the cathode 14 is metallic aluminum, with a thickness of 100 nm.

[0064] The specific preparation method of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment is as follows: After ultrasonically cleaning the glass substrate 1 with the anode 2 in the washing solution for 90 minutes, it is washed with deionized water and dried with nitrogen, and then placed in a vacuum oven at 120 °C for baking for 30 minutes; the dried ITO glass is treated with oxygen plasma for 4 minutes to further remove the impurities remaining on the ITO surface, and then it is transferred into the vacuum evaporation system. When the vacuum degree in the vacuum evaporation system reaches ~10 -5 Pa, a hole blocking layer 3, an electron transport layer 4, a photoactive layer 5, a hole transport layer 6, a light-emitting layer 7, an electron transport layer 8, a connection layer 9, a hole transport layer 10, a light-emitting layer 11, an electron transport layer 12, an electron injection layer 13, and a metal cathode 14 are sequentially evaporated on the ITO anode 2. Among them, the device is composed of the overlapping part of two electrodes, and its effective area is 20 mm 2 , and finally a structure of Glass / ITO / ZnO(35 nm) / C 60 (30 nm) / TAPC:C70 (15%, 200 nm) / TAPC(10 nm) / TCTA(5 nm) / mCBP(5 nm) / mCBP:PO-T2T:FIrpic(1:1:0.15, 30 nm) / PO-T2T(35 nm) / Liq(1.5 nm) / Al(1 nm) / HAT-CN(10 nm) / TAPC(5 nm) / TCTA(5 nm) / mCBP(5 nm) / mCBP:PO-T2T:FIrpic(1:1:0.15, 30 nm) / PO-T2T(35 nm) / Liq(1.5 nm) / Al(100 nm).

[0065] The working principle of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment is the same as that in Embodiment 1.

[0066] Figure 9 This is the normalized absorption spectrum of the photoactive layer of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment. As can be seen from the figure, the absorption spectrum range of TAPC is 300 - 400 nm, C 70 has good absorption in the visible light range, and the main absorption spectrum range is 300 - 700 nm, TAPC:C 70 The main absorption spectrum range of the blend film is 300 - 700 nm, and the absorption efficiency for visible light is much higher than that of C 60 .

[0067] Figure 10 This is the external quantum efficiency curve graph of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment. As can be seen from the figure, as the positive external bias voltage increases, the external quantum efficiency of the device increases significantly. At a bias voltage of 7.5 V, the external quantum efficiency in the wavelength range of 300 - 800 nm exceeds 100%, and the maximum external quantum efficiency at a wavelength of 400 nm reaches 2483%.

[0068] Figure 11 This is the dark current curve graph of the visual optical signal detection device based on the optical regeneration gain mechanism in this embodiment. As can be seen from the figure, at a bias voltage of 8 V, the device still has an ultra-low dark current on the order of 9×10 -8 Acm -2 magnitude.

[0069] Figure 12For detecting a light source with the words "SCUT" using the visual optical signal detection device based on the optical regeneration gain mechanism of this embodiment, the image of the light source displayed on the device surface. Using the visual optical signal detection device based on the optical regeneration gain mechanism of this embodiment to detect one, two, three, and four circular light sources respectively, the images of the light sources displayed on the device surface are as shown in Figure 13 (a)-(d) in the figure. Figure 14 It is the relationship curve between the photocurrent and the number of circular light sources. It can be seen from the figure that under the illumination of light sources with different numbers, the number and shape of the light spots can be clearly seen on the device. According to the relationship that the number of light spots is proportional to the photocurrent, the uniformity of the device can be reflected.

[0070] The visual optical signal detection device based on the optical regeneration gain mechanism of this embodiment can be assembled with a DC power supply and a current measurement unit into a visual optical signal detection device based on the optical regeneration gain mechanism. The current measurement unit is used to measure and display the photocurrent at the transparent anode. When conducting detection work, the magnitude of the photocurrent can reflect the distance between the device and the light source to a certain extent, which is beneficial for quickly finding the light source; the DC power supply is connected to the anode and the anode connection of the visual optical signal detection device based on the optical regeneration gain mechanism to provide the working voltage.

[0071] In this embodiment, under the continuous illumination of the light source to be measured, the optical regeneration phenomenon occurs cyclically in the device, and the self-generated photocurrent continuously increases, enabling the photocurrent at the anode to be amplified. At the same time, the dark current is low and the detection sensitivity is high, which is beneficial for the detection of weak optical signals. And there is no need for an additional display unit, and the image of the light source is directly imaged on the visual optical signal detection device based on the optical regeneration gain mechanism, which is beneficial for simplifying the structure of the detection device.

[0072] In the above embodiment, the light-emitting unit can also be designed as one, three, or other numbers according to the actual situation.

[0073] The above embodiment is a preferred embodiment of the present invention, but the embodiments of the present invention are not limited by the described embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A visual optical signal detection device based on optical regeneration gain mechanism, characterized in that: It includes a transparent substrate, a transparent anode, a light detection unit, at least one light emitting unit, an electron injection layer, and a cathode in sequence; The light detection unit comprises a hole blocking layer, a first electron transport layer, and a photoactive layer in sequence; the photoactive layer is formed by mixing TAPC and fullerene; the fullerene is C 60 or C 70 ; The light-emitting unit comprises a hole transport layer, a light-emitting layer, and a second electron transport layer in sequence; the light-emitting layer has an exciplex as a main body and a phosphorescent material as a guest; When the visualized optical signal detection device is working, under the illumination of the measured light source and the action of forward bias, the photoactive layer absorbs incident photons to generate photogenerated electrons and photogenerated holes; the photogenerated electrons drift to the anode to form an incident photocurrent, and the photogenerated holes drift to the light-emitting layer to recombine with the electrons injected by the cathode to generate self-generated photons; a part of the self-generated photons are emitted from the transparent substrate to form an image of the light source on the visualized optical signal detection device; the other part of the self-generated photons are absorbed by the photoactive layer and photoregeneration occurs: the photoactive layer absorbs self-generated photons to generate self-generated photogenerated electrons and self-generated photogenerated holes, the self-generated photogenerated electrons form a self-generated photocurrent at the anode, and the self-generated photogenerated holes drift to the light-emitting layer to recombine with the electrons injected by the cathode to generate new self-generated photons; under the continuous illumination of the measured light source, the photoactive layer continuously absorbs incident photons to drive the light-emitting layer to generate self-generated photons, photoregeneration continues to occur, the number of self-generated photons continues to increase, and the self-generated photocurrent continues to increase, thereby achieving photocurrent gain.

2. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 1, characterized in that: In the photoactive layer, the mass concentration of TAPC is 5wt%-50wt%; and the thickness of the photoactive layer is 50-200 nm.

3. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 1, characterized in that: The exciplex is prepared by mixing mCBP and PO-T2T in a mass ratio of 1: (0.8-1.2).

4. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 1, characterized in that: The phosphorescent material is FIrpic; in the light-emitting layer, the mass concentration of the phosphorescent material is 6% to 30%.

5. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 1, characterized in that: The hole blocking layer is ZnO or BCP, and has a thickness of 10-50 nm.

6. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 1, characterized in that: The hole transport layer is a three-layer structure, including a TAPC layer, a TCTA layer and an mCBP layer.

7. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 6, characterized in that: The thickness of the TAPC layer is 5-60 nm, the thickness of the TCTA layer is 3-10 nm; and the thickness of the mCBP layer is 3-10 nm.

8. The visualized optical signal detection device based on the optical regeneration gain mechanism according to any one of claims 1 to 7, characterized in that: When two or more light emitting units are included, a connection layer is provided between the light emitting units.

9. The visual optical signal detection device based on the optical regeneration gain mechanism according to claim 8, characterized in that: The connecting layer includes a Liq layer with a thickness of 1.5 to 2.5 nm, an Al layer with a thickness of 0.5 to 1.5 nm, and a HAT-CN layer with a thickness of 5 to 20 nm.

10. A visual optical signal detection device based on optical regeneration gain mechanism, characterized in that: It comprises a direct current power supply, a current measuring unit and a visualized optical signal detection device based on the optical regeneration gain mechanism as described in any one of claims 1 to 9; the current measuring unit is used to measure the photocurrent at the transparent anode.

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