Nail integrated system for monitoring cardiovascular health of human body

Abstract

The invention provides a fingernail integrated system for monitoring cardiovascular health of a human body, which is characterized in that firstly, a photoelectric detector device performs matching between energy bands to construct a built-in electric field through different energy band structures of materials, when light irradiates a light active layer, electron absorption energy jumps to a conduction band to generate electron-hole pairs, and the energy of the conduction band of an electron transport layer is relatively low, so that the electron-hole pairs are generated; electrons flow to the electron transport layer and are conducted away by the electrode, and holes left in a valence band flow to the hole transport layer and are conducted away by the electrode, so that the device can generate current under the condition of not applying voltage, which indicates that the photoelectric detector can operate under the condition of low power consumption; meanwhile, due to the vertical structure and the self-powered characteristic of the photoelectric detector, the area of the device can be greatly reduced, a patterned electrode can be designed, the size of the electrode can be freely adjusted, and therefore personalized and miniaturized electrode preparation is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of integrated manufacturing technology in the field of semiconductor and medical treatment, and particularly relates to a nail integrated system for cardiovascular health monitoring of human body. BACKGROUND

[0002] At present, the number of people who die of cardiovascular diseases accounts for about 30% of the number of people who die in the world, however, most of the cardiovascular diseases can be prevented through early monitoring, and most of the health monitoring devices on the market cannot test heart rate and blood oxygen under the condition that the human body is active, in order to solve this problem, flexibility and miniaturization are introduced into the preparation of the device.

[0003] Photoelectric plethysmogram is a method for noninvasive measurement of cardiovascular health signals of human body, and its principle is based on that a photodetector converts a light signal reflected by the human body into an electric signal, the frequency of the electric signal shows the heart rate of the human body, and because the oxygenated hemoglobin and deoxygenated hemoglobin in the human body have large absorption difference in the red light and green light wave bands, the blood oxygen saturation can be calculated through a formula. Perovskite material has the advantages of simple preparation process, low cost and strong light absorption characteristics, and preparation of the material into a vertical structure self-powered photodetector is conducive to the flexibility and miniaturization of the device, so as to realize cardiovascular health signal monitoring without motion artifacts. SUMMARY

[0004] In order to solve the above problems, the present application provides a nail integrated system for cardiovascular health monitoring of human body, which can greatly reduce the device area, can also design a patterned electrode and adjust the electrode size arbitrarily, and realize personalized and miniaturized electrode preparation.

[0005] A nail integrated system for cardiovascular health monitoring of human body, comprising a terminal application program, a PPG signal acquisition module attached to the nail cover of a measured user, and a front-end probe worn on the back of the measured user and a rear-end circuit board; wherein the PPG signal acquisition module comprises a photodetector, a red light LED, a green light LED and a serpentine printed circuit.

[0006] The red light LED and the green light LED emit red light and green light for irradiating the finger in time; the photodetector is used for receiving red reflected light and green reflected light reflected by human tissue, and generating a first current corresponding to the red reflected light and a second current corresponding to the green reflected light under the action of the red reflected light and the green reflected light respectively; the serpentine printed circuit is used for transmitting the first current and the second current to the front-end probe, and then transmitting the first current and the second current to the rear-end circuit board by the front-end probe; the front-end probe is further used for sending state information of the finger monitored by the front-end probe to the rear-end circuit board; and the rear-end circuit board is used for generating a photoplethysmogram according to the first current and the second current, determining a motion state of the finger according to the state information, and sending the photoplethysmogram and the motion state to a terminal application program for display.

[0007] Further, the front-end probe comprises five soldering points and a motion sensor; two soldering points are used for connecting input ends and output ends of the photodetector respectively, another two soldering points are used for connecting input ends of the red light LED and the green light LED respectively, and the last soldering point is used for connecting a common output end of the red light LED and the green light LED.

[0008] The motion sensor is used for monitoring state information of the finger, wherein the state information comprises joint angle information and joint acceleration information.

[0009] Further, the photodetector comprises, from bottom to top, a substrate, a bottom electrode layer, a hole transport layer, a photoactive layer, an electron transport layer and a top electrode layer; the substrate is used for providing a flexible base for material deposition, the bottom electrode layer, the hole transport layer, the photoactive layer, the electron transport layer and the top electrode layer are sequentially deposited on the substrate to form a vertical device structure; and a method for generating a current by the photodetector is as follows:

[0010] When the red reflected light or the green reflected light irradiates the photoactive layer, electrons in the photoactive layer absorb energy and jump to a conduction band to generate electron-hole pairs, the electrons flow to the electron transport layer with lower conduction band energy and are guided away by the top electrode layer, and the holes left in the valence band of the photoactive layer flow to the hole transport layer and are guided away by the bottom electrode layer, so that the photodetector generates a current without applying a voltage.

[0011] Further, the material of the substrate is PET or flexible PI, the material of the bottom electrode layer is ITO, the material of the hole transport layer is PEDOT:PSS, the material of the photoactive layer is CsBi3I 10 , the material of the electron transport layer is PC 61 BM, and the material of the top electrode layer is gold.

[0012] Further, a preparation method of the photodetector is as follows:

[0013] S1: selecting a substrate;

[0014] S2: preparing a 125-micrometer-thick bottom electrode layer on the substrate by magnetron sputtering;

[0015] S3: sequentially spin-coating a hole transport layer, a photoactive layer, and an electron transport layer on the bottom electrode layer;

[0016] S4: evaporating a 0.5 mm x 0.5 mm square-shaped top electrode layer above the electron transport layer.

[0017] Further, the substrate is sequentially subjected to a first cleaning treatment and a second cleaning treatment before the bottom electrode layer is prepared, the first cleaning treatment is a decontamination treatment, and the second cleaning treatment is used to improve the hydrophilicity of the substrate.

[0018] Further, the method for preparing the hole transport layer on the bottom electrode layer is:

[0019] PEDOT:PSS solution is spin-coated on the substrate plated with the bottom electrode layer, and then the whole is heated on a hot stage at 150 degrees Celsius for 15 minutes, wherein the spin-coating speed is 4000 revolutions, and the spin-coating time is 40 seconds.

[0020] Further, the preparation step of the photoactive layer comprises:

[0021] 0.1299 grams of cesium iodide powder and 0.8846 grams of bismuth iodide powder are mixed and dissolved in a mixed solution of dimethyl sulfoxide and dimethyl formamide in a mixing ratio of 1:9 and a mixing volume of 1 milliliter;

[0022] The mixed solution is stirred at room temperature for 12 hours to form a CsBi3I 10 solution, and the prepared CsBi3I 10 solution is placed in an argon gas-protected glove box;

[0023] After the substrate covered with the hole transport layer and the bottom electrode layer is transferred to the glove box, the CsBi3I 10 solution is spin-coated above the hole transport layer, wherein the spin-coating speed is 6000 revolutions, the spin-coating time is 30 seconds, and 180 microliters of toluene is added dropwise above the hole transport layer at the 8th second of spin-coating;

[0024] After spin-coating is completed, the whole is placed on a hot stage at 125 degrees Celsius for heating treatment for 25 minutes.

[0025] Further, the preparation step of the electron transport layer comprises:

[0026] 0.02 grams of PC 61 BM powder is dissolved in 1 milliliter of chlorobenzene;

[0027] The solution with PC 61BM powder is chlorobenzene 12 hours, PC is formed 61 BM solution, and the PC 61 BM solution is placed in an argon gas protection glove box;

[0028] PC 61 The BM solution is drop-coated on the substrate covered with the bottom electrode layer, the hole transport layer and the photoactive layer, and is left for 10 seconds, and then is spin-coated at a rotation speed of 3000 revolutions per minute for 30 seconds;

[0029] After the spin-coating is completed, the whole is heated on an annealing table at 80 degrees Celsius for ten minutes.

[0030] Further, the upper and lower surfaces of the PPG signal acquisition module are packaged with parylene.

[0031] Beneficial effects:

[0032] 1. The nail integrated system for human cardiovascular health monitoring provided by the present application firstly matches the built-in electric field between energy bands through the different energy band structures of materials of the photodetector device, when light irradiates the photoactive layer, the electron absorbs energy and transitions to the conduction band to generate electron-hole pairs, because the conduction band energy of the electron transport layer is low, the electron flows to the electron transport layer and is led away by the electrode, and the hole left in the valence band flows to the hole transport layer and is led away by the electrode, so that the device can generate current without applying voltage, which indicates that the photodetector device can operate under low power consumption; at the same time, the photodetector can greatly reduce the device area due to its vertical structure and self-powered characteristics, and the patterned electrode can also be designed and the electrode size can be adjusted arbitrarily, so as to realize the preparation of individualized and miniaturized electrodes.

[0033] 2. The nail integrated system for human cardiovascular health monitoring provided by the present application sequentially deposits ITO layer, hole transport layer, photoactive layer and electron transport layer on the substrate, the thickness of the photoactive layer is about 500 nanometers, and the preparation processes of the three layers are all simple solution spin coating methods, without the need of vacuum high pressure environment, which can further reduce the production cost.

[0034] 3. The nail integrated system for human cardiovascular health monitoring provided by the present application selects the nail shell as the application position, the nail belongs to a semi-rigid position, which is more likely to reduce the influence of motion artifacts than the traditional application positions such as skin.

[0035] 4. The nail integrated system for human cardiovascular health monitoring provided by the present application selects a non-toxic and flexible lead-free perovskite material to prepare the photodetector, connects by printing circuit, and finally encapsulates the PPG signal acquisition module by using parylene, which is harmless to the human body and has strong biocompatibility. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A schematic diagram of a nail integrated system for human cardiovascular health monitoring is provided in the present application;

[0037] Figure 2 A schematic diagram of a PPG signal acquisition module is provided in the present application;

[0038] Figure 3 A schematic diagram of wearing a photodetector and an LED on a nail is provided in the present application;

[0039] Figure 4 A photodetector is provided in the present application;

[0040] Figure 5 A partial photo of a photodetector structure under scanning electron microscope is provided in the present application;

[0041] Figure 6 A schematic diagram of wearing a front-end probe and a rear-end circuit board on a hand is provided in the present application;

[0042] Figure 7 A PPG signal obtained by a health monitoring system is provided in the present application;

[0043] Figure 8 A customized mobile phone APP interface is provided in the present application. DETAILED DESCRIPTION

[0044] In order to enable personnel in the art to better understand the present application, the technical solutions in the present application will be described clearly and completely below in conjunction with the accompanying drawings in the present application.

[0045] The present application provides a nail integrated system for human cardiovascular health monitoring, which belongs to a self-powered photodetector based on energy band structure and a human cardiovascular health monitoring system integrated with a light source, and specifically comprises a terminal application program, a PPG signal acquisition module attached to the nail cover of a user to be measured, and a front-end probe and a rear-end circuit board worn on the back of a hand of the user to be measured; the PPG signal acquisition module comprises a photodetector, a red light LED, a green light LED, and a serpentine printed circuit, the upper and lower surfaces of the PPG signal acquisition module are packaged with parylene, the serpentine printed circuit is used as a serpentine silver paste electrode, and is printed by a high-density paste printer, and has a width of about 0.5 mm.

[0046] The red light LED and the green light LED emit red light and green light for irradiating the finger in time; the photodetector is used for receiving red reflected light and green reflected light reflected by human body tissue, and generating a first current corresponding to the red reflected light and a second current corresponding to the green reflected light under the action of the red reflected light and the green reflected light respectively; the serpentine printed circuit is used for transmitting the first current and the second current to the front-end probe, and then transmitting the first current and the second current to the rear-end circuit board by the front-end probe; the front-end probe is further used for sending state information of the finger monitored by the front-end probe to the rear-end circuit board; and the rear-end circuit board is used for generating a photoplethysmogram according to the first current and the second current, determining a motion state of the finger according to the state information, and sending the photoplethysmogram and the motion state to a terminal application program for display.

[0047] Figure 7 The PPG signal obtained by the health monitoring system according to the present application. As shown in Figure 7 , the light intensity of the red light LED is: 1.16 mW / cm 2 ; the light intensity of the green light LED is: 1.09 mW / cm 2 ; and the obtained PPG signal has obvious dicrotic wave under the light of the two wavelengths, which indicates that the system has the ability to detect human signals.

[0048] Further, as shown in Figure 1 , the front-end probe includes five solder joints and a motion sensor; two solder joints are used for connecting the input end and the output end of the photodetector respectively, another two solder joints are used for connecting the input end of the red light LED and the green light LED respectively, and the last solder joint is used for connecting the common output end of the red light LED and the green light LED; the motion sensor is used for monitoring state information of the finger, and the state information includes joint angle information and joint acceleration information. Figure 6 The camera photograph of the front-end probe and the rear-end circuit board shown in Figure 1 worn on the hand. As shown in Figure 6 , the front-end probe is worn on the index finger, and the rear-end circuit board is worn on the back of the hand. Figure 3 The schematic diagram of wearing the photodetector and the LED on the nail. As shown in Figure 3 , the curvature of the nail is beneficial to the propagation of the reflected light reflected by the human body tissue, and avoids the influence of skin wrinkles and sweat on the test. Figure 2 The camera photograph of the schematic diagram of the wearing device shown in Figure 3 . As shown in Figure 2 , the photodetector and the two LEDs are respectively located on both sides of the nail, and the photodetector is located on the central axis of the two LEDs.

[0049] Meanwhile, as shown in Figure 1As shown, the back-end circuit board includes a micro control unit, a level converter, a voltage regulator, a Bluetooth module and the like for amplifying, filtering and transmitting the light-emitting control signals of the LED and the photodetector signals; for example, the back-end circuit board collects the current signals of the photodetector, converts them into voltage, amplifies and filters them, and transmits them to a customized terminal application program, such as a mobile phone APP, through a Bluetooth element. The terminal application program includes three modules, the first module displays the PPG signal, the second module displays the finger movement condition monitored by the motion sensor, and the third module displays the heart rate and blood oxygen calculated finally.

[0050] As shown in the drawings, Figure 8 , the customized mobile phone APP interface provided by the present application is divided into three parts. The first part is the display of the PPG signal; the second part is the motion state of the human finger monitored by the motion sensor; and the third part is the display area of the heart rate and blood oxygen saturation calculated.

[0051] As shown in the drawings, Figure 4 , the photodetector is sequentially arranged from bottom to top as a substrate, a bottom electrode layer, a hole transport layer, a photoactive layer, an electron transport layer, and a top electrode layer. Figure 5 is Figure 4 a local photo of the photodetector structure scanned under an electron microscope, as shown in the drawings, Figure 5 , the bottom electrode layer, the hole transport layer, the photoactive layer and the electron transport layer are sequentially deposited. Specifically, the substrate is used as a flexible substrate for material deposition, and the bottom electrode layer, the hole transport layer, the photoactive layer, the electron transport layer and the top electrode layer are sequentially deposited on the substrate to form a vertical device structure; the material of the substrate is selected from flexible polyethylene terephthalate PET or flexible polyimide film PI, the material of the bottom electrode layer is selected from ITO, the material of the hole transport layer is selected from PEDOT: PSS, the material of the photoactive layer is selected from CsBi3I 10 , the material of the electron transport layer is selected from PC 61 BM, and the material of the top electrode layer is selected from gold; based on this, the method for generating current by the photodetector is:

[0052] When the red reflected light or the green reflected light irradiates the photoactive layer, the electrons in the photoactive layer absorb energy and transition to the conduction band to form electron-hole pairs, the electrons flow to the electron transport layer with lower conduction band energy and are guided away by the top electrode layer, and the holes left in the valence band of the photoactive layer flow to the hole transport layer and are guided away by the bottom electrode layer, so that the photodetector generates current without applying voltage.

[0053] That is to say, when the light beam irradiates the finger, the light reflected by the human tissue is irradiated on the photodetector device, the photoactive layer generates electron-hole pairs, under the action of the built-in battery, the carriers drift, and the current is formed without external bias. With the contraction and relaxation of the human heart, the light reflected by the human tissue shows periodic changes, and the device also shows periodic waveforms.

[0054] Further, the preparation method of the photodetector is as follows:

[0055] S1: selecting a substrate;

[0056] It should be noted that the substrate is sequentially subjected to first cleaning treatment and second cleaning treatment before the preparation of the bottom electrode layer, the first cleaning treatment is decontamination treatment, and the second cleaning treatment is used to improve the hydrophilicity of the substrate.

[0057] For example, take a substrate 1, such as a PET substrate or a PI substrate, cut the substrate 1 into a size of 1 cm x 1 cm; the prepared substrate 1 is sequentially placed in acetone, ethanol and deionized water for ultrasonic cleaning for 10 minutes, and then dried by high-purity nitrogen gas to be used as the first cleaning treatment, which realizes the effect of removing impurities and oil stains;

[0058] S2: preparing a bottom electrode layer with a thickness of 125 microns on the substrate after the first cleaning treatment and the second cleaning treatment by a magnetron sputtering method; the bottom electrode layer is indium tin oxide (ITO);

[0059] S3: sequentially spin-coating a hole transport layer, a photoactive layer and an electron transport layer on the bottom electrode layer by using a solution spin coating method; wherein the hole transport layer is made of a PEDOT:PSS solution; the photoactive layer is made of a CsBi3I 10 solution; and the electron transport layer is made of a PC 61 BM solution;

[0060] It should be noted that the substrate with ITO sputtered in step S2 can be placed in a glass culture dish and cleaned by a plasma machine for 10 minutes to complete the second cleaning treatment, so that the surface of the substrate 1 is more hydrophilic, which helps the solution to spread to form a film. The gas used for cleaning can be selected as oxygen. Then, the spin coating of the hole transport layer, the photoactive layer and the electron transport layer is performed.

[0061] Specifically, the method for preparing the hole transport layer on the bottom electrode layer is as follows:

[0062] The PEDOT:PSS solution is spin-coated on the substrate plated with the bottom electrode layer, and then the whole is heated on a hot table at 150 degrees Celsius for 15 minutes, wherein the spin-coating speed is 4000 revolutions, and the spin-coating time is 40 seconds.

[0063] Further, the preparation step of the photoactive layer comprises:

[0064] 0.1299 grams of cesium iodide powder and 0.8846 grams of bismuth iodide powder are mixed and dissolved in a mixed solution of dimethyl sulfoxide and dimethyl formamide in a mixing ratio of 1:9, with a mixed volume of 1 milliliter;

[0065] The mixed solution is stirred for 12 hours under normal temperature conditions to form a CsBi3I 10 solution, and the prepared CsBi3I 10 solution is placed in an argon gas-protected glove box;

[0066] After the substrate covered with the hole transport layer and the bottom electrode layer is transferred to the glove box, the CsBi3I 10 solution is spin-coated above the hole transport layer, wherein the spin-coating speed is 6000 revolutions, the spin-coating time is 30 seconds, and 180 microliters of toluene is added dropwise above the hole transport layer at the 8th second of spin-coating;

[0067] After spin-coating is completed, the whole is placed on a hot stage at 125 degrees Celsius for heating treatment for 25 minutes.

[0068] Further, the preparation step of the photoactive layer comprises:

[0069] 0.02 grams of PC 61 BM powder is dissolved in chlorobenzene with a volume of 1 milliliter;

[0070] The solution with PC 61 BM powder dissolved in chlorobenzene is stirred for 12 hours under normal temperature conditions to form a PC 61 BM solution, and the prepared PC 61 BM solution is placed in an argon gas-protected glove box;

[0071] The PC 61 BM solution is drop-coated on the substrate covered with the bottom electrode layer, the hole transport layer and the photoactive layer, and is left to stand for 10 seconds, and then is spin-coated at a speed of 3000 revolutions for 30 seconds;

[0072] After spin-coating is completed, the whole is placed on an annealing stage at 80 degrees Celsius for heating treatment for ten minutes.

[0073] S4: A square top electrode layer with a size of 0.5 mm x 0.5 mm is evaporated above the electron transport layer.

[0074] So far, the present application prepares a vertical structure photoelectric detector, when the light beam passes through the human body, the reflected light presents a periodic light signal with the contraction and relaxation of the human heart, the photoactive layer generates electron hole pairs when the light signal is reflected to the device, the carriers drift under the action of the energy band structure, and the device presents a periodic electric signal, that is, the PPG signal.

[0075] Of course, the present application can have other various embodiments, and those skilled in the art can certainly make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications shall all belong to the protection scope of the claims attached to the present application.

Claims

1. A nail-integrated system for monitoring human cardiovascular health, characterized in that, It includes a terminal application, a PPG signal acquisition module that is applied to the fingernail of the user being tested, and a front-end probe and a back-end circuit board that are worn on the back of the user's hand; wherein, the PPG signal acquisition module includes a photodetector, a red LED, a green LED, and a snake-shaped printing circuit. The red and green LEDs emit red and green light in a time-division manner to illuminate the fingers. The photodetector receives the red and green reflected light from human tissue and generates a first current corresponding to the red reflected light and a second current corresponding to the green reflected light, respectively. The serpentine printing circuit transmits the first and second currents to the front-end probe, which then forwards them to the back-end circuit board. The front-end probe also sends the finger status information it monitors to the back-end circuit board. The back-end circuit board generates a photoplethysmogram based on the first and second currents, determines the finger's movement state based on the status information, and sends the photoplethysmogram and movement state to the terminal application for display.

2. The integrated nail system for monitoring human cardiovascular health as described in claim 1, characterized in that, The front-end probe includes five solder points and a motion sensor; two solder points are used to connect to the input and output ends of the photodetector, respectively; two other solder points are used to connect to the input ends of the red LED and the green LED, respectively; and the last solder point is used to connect to the common output end of the red LED and the green LED. The motion sensor is used to monitor the obtained finger state information, which includes joint angle information and joint acceleration information.

3. The integrated nail system for monitoring human cardiovascular health as described in claim 1, characterized in that, The photodetector, from bottom to top, comprises a substrate, a bottom electrode layer, a hole transport layer, a photoactive layer, an electron transport layer, and a top electrode layer. The substrate provides a flexible base for material deposition. The bottom electrode layer, hole transport layer, photoactive layer, electron transport layer, and top electrode layer are sequentially deposited on the substrate to form a vertical device structure. The photodetector generates current using the following method: When red or green reflected light irradiates the photoactive layer, electrons in the photoactive layer absorb energy and jump to the conduction band, generating electron-hole pairs. Electrons flow to the electron transport layer with lower energy in the conduction band and are guided away by the top electrode layer. Holes remaining in the valence band of the photoactive layer flow to the hole transport layer and are guided away by the bottom electrode layer, enabling the photodetector to generate current without applying voltage.

4. The integrated nail system for monitoring human cardiovascular health as described in claim 3, characterized in that, The substrate material is PET or flexible PI, the bottom electrode layer material is ITO, the hole transport layer material is PEDOT:PSS, and the photoactive layer material is CsBi3I. 10 The electron transport layer is made of PC. 61 BM, the top electrode layer is made of gold.

5. The integrated nail system for monitoring human cardiovascular health as described in claim 3, characterized in that, The method for fabricating the photodetector is as follows: S1: Select substrate; S2: A 125-micrometer-thick bottom electrode layer is fabricated on the substrate by magnetron sputtering; S3: Sequentially spin-coat the hole transport layer, photoactive layer and electron transport layer onto the bottom electrode layer; S4: A square top electrode layer of 0.5mm × 0.5mm is deposited above the electron transport layer.

6. The integrated nail system for monitoring human cardiovascular health as described in claim 5, characterized in that, Before the bottom electrode layer is fabricated, the substrate undergoes a first cleaning process and a second cleaning process in sequence. The first cleaning process is a decontamination process, and the second cleaning process is used to improve the hydrophilicity of the substrate.

7. The integrated nail system for monitoring human cardiovascular health as described in claim 5, characterized in that, The method for fabricating a hole transport layer on the bottom electrode layer is as follows: PEDOT:PSS solution was spin-coated onto a substrate with a bottom electrode layer, and then the entire substrate was heated on a hot plate at 150 degrees Celsius for 15 minutes. The spin-coating speed was 4000 rpm and the spin-coating time was 40 seconds.

8. The integrated nail system for monitoring human cardiovascular health as described in claim 5, characterized in that, The preparation steps of the photoactive layer include: 0.1299 g of cesium iodide powder and 0.8846 g of bismuth iodide powder were mixed and dissolved in a mixed solution of dimethyl sulfoxide and dimethylformamide with a mixing ratio of 1:9 and a mixing volume of 1 mL. The mixed solution was stirred at room temperature for 12 hours to form CsBi3I. 10 Solution, and the prepared CsBi3I 10 The solution was placed in a glove box protected by argon gas; After transferring the substrate covered with the hole transport layer and the bottom electrode layer to the glove box, CsBi3I 10 The solution was spin-coated above the hole transport layer at a speed of 6000 rpm for 30 seconds, and 180 μL of toluene was added above the hole transport layer at the 8th second of spin-coating. After spin coating, the entire product is placed on a hot table at 125 degrees Celsius and heated for 25 minutes.

9. The integrated nail system for monitoring human cardiovascular health as described in claim 5, characterized in that, The fabrication steps of the electron transport layer include: 0.02 grams of PC 61 BM powder was dissolved in 1 ml of chlorobenzene; PC dissolved under stirring at room temperature 61 BM powder in chlorobenzene for 12 hours to form PC 61 BM solution, and the prepared PC 61 The BM solution was placed in a glove box protected by argon gas. PC 61 The BM solution was drop-coated onto a substrate covered with a bottom electrode layer, a hole transport layer and a photoactive layer, left to stand for 10 seconds, and then spin-coated at 3000 rpm for 30 seconds. After spin coating, the entire product is placed on an annealing table at 80 degrees Celsius and heated for ten minutes.

10. The integrated nail system for monitoring human cardiovascular health as described in claim 1, characterized in that, The upper and lower surfaces of the PPG signal acquisition module are encapsulated with parylene.

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