Wireless infrared quantum dot light emitting diode and biological detection imaging system

Abstract

The invention discloses a wireless infrared quantum dot light-emitting diode and a biological detection imaging system. The wireless infrared quantum dot light-emitting diode comprises an infrared quantum dot light-emitting part and an electromagnetic induction energy pumping part, an insulating shell layer is arranged outside the light-emitting device, and a conductive loop is arranged on the shell layer to be communicated with the cathode and the anode. The wireless quantum dot light-emitting diode does not need an external power supply to inject current, but excites induced electromotive force in a cathode-light-emitting device-anode-connected loop through an external variable electromagnetic field, and forms induced current, and the induced current drives the quantum dot light-emitting diode to generate electroluminescence. A miniaturized wireless quantum dot light-emitting diode is injected into a living body, a high-frequency coil is utilized to excite the wireless quantum dot light-emitting diode in the living body to emit light outside the living body, and an infrared camera is utilized to shoot an infrared image of the living body. The living body infrared imaging system is large in detection depth, and images not only provide internal structure information of a living body, but also comprise metabolism information.

Description

Technical Field

[0001] This invention relates to the fields of luminescence and imaging, and in particular to non-destructive bioimaging. Background Technology

[0002] In medical testing and diagnosis, non-invasive imaging of patients is of great significance. Through non-invasive imaging, doctors can gain a comprehensive understanding of internal lesions without surgery. However, because conventional cameras are only sensitive to visible light, which cannot penetrate living organisms, non-invasive imaging techniques for biological materials are very limited.

[0003] Ultrasound was one of the earliest applications of non-destructive imaging of biological organisms, and its working mechanism is as follows: Figure 1 As shown, the system includes a living organism 1, a coupling fluid 2, an ultrasonic transducer 3, a transmitter 4, a pulse generator 5, a scanning generator 6, a receiver 7, and an image display terminal 8. In this imaging, ultrasound is used as an imaging probe. Typically, the piezoelectric effect is utilized to convert electrical energy into ultrasonic energy through the ultrasonic transducer 3. The ultrasound waves are projected onto the living organism 1 through the coupling fluid 2. Due to the relatively long wavelength of ultrasound, it penetrates deeply into the living organism. The receiver 7 can detect the internal structural information of the living organism through the reflected ultrasound signals, and through signal amplification and image processing, a non-destructive examination image of the living organism is finally obtained on the image display terminal 8. Although the long wavelength of ultrasound is used to detect the internal structure of living organisms, this characteristic also results in lower spatial resolution and higher noise in the imaging.

[0004] X-ray imaging is another commonly used non-destructive imaging method for biological organisms. Its working mechanism is as follows: Figure 2 As shown, the system includes a biological organism 1, an image display terminal 8, an X-ray source 9, and an X-ray detector 10. It utilizes the X-ray source 9 to generate high-energy X-ray photons and uses X-rays as an imaging probe. Because X-ray photons have very high energy, they have strong penetrating power into biological organisms, allowing for non-destructive imaging of the organism via the X-ray detector 10. Compared to ultrasound non-destructive imaging, X-rays have a very short wavelength, so the spatial resolution of X-ray imaging can reach tens of micrometers. However, due to the high energy of X-ray photons, they can also cause ionization of biomolecules. Studies have shown that high doses of X-ray radiation increase the probability of patients developing cancer and other diseases; therefore, reducing ionizing radiation in non-destructive imaging of biological organisms is an urgent problem that needs to be solved.

[0005] Infrared radiation can penetrate to a certain depth into living organisms, and infrared photons have very low energy. They belong to electromagnetic radiation and will not cause ionizing damage to living organisms. Therefore, infrared non-destructive imaging of living organisms has become a research hotspot. Figure 3A typical infrared bioimaging system is presented, comprising an organism 1, an infrared light source 11, infrared illumination 12, and an infrared camera 13. The infrared light source 11 generates infrared illumination 12, which illuminates the organism and penetrates to a certain depth. The reflected infrared light is received by the infrared camera 13 to form a biological image. Numerous studies have shown that as the wavelength of infrared light increases, for example from the NIR-I region to the NIR-II region, its penetration depth into organisms can reach centimeters or more. Using infrared bioimaging, the spatial resolution can also reach tens of micrometers, and it does not cause ionizing radiation damage. Therefore, compared with ultrasound and X-ray imaging, infrared bioimaging has unique advantages.

[0006] exist Figure 3 In the infrared imaging system shown, infrared light source 11 generates infrared illumination, and infrared camera 13 and infrared light source 11 are located on one side of the organism. Infrared light enters the camera through two processes: incident and reflection, which to some extent reduces the penetration depth of infrared light into the organism. Meanwhile, the intensity distribution of infrared light is mainly determined by infrared light source 11 and has no direct relationship with the organism's metabolism and blood circulation. In recent years, some research groups have proposed injecting infrared luminescent nanoparticles into the blood vessels of organisms, applying pump light outside the organism, and exciting the nanoparticles inside the organism to generate infrared photoluminescence. The infrared light signal emitted by the nanoparticles is received by an infrared camera, thus obtaining an infrared image of the organism. However, pump light is generally short-wavelength visible or ultraviolet light, and visible and ultraviolet light have poor penetration ability into organisms, so the observation depth of the infrared photoluminescence method using nanoparticles is very small. To address the above problems, this invention proposes an infrared nanoparticle electroluminescent structure, using a time-varying electromagnetic field as an energy probe to excite infrared electroluminescence within the organism, obtaining infrared images with superior performance. Summary of the Invention

[0007] Objective of the Invention: This invention addresses the significant need for non-destructive testing imaging in biology and the problems existing in current technologies by proposing a wireless infrared quantum dot light-emitting diode (LED) structure and a biological non-destructive testing imaging system constructed using this LED. The wireless infrared quantum dot LED utilizes a high-frequency electromagnetic field as an energy source, inducing a current in the LED circuit through electromagnetic induction, thereby generating infrared electroluminescence. A miniaturized wireless quantum dot LED is injected into a living organism, and a high-frequency coil outside the organism excites the internal LED to emit light. An infrared camera then captures an infrared image of the organism. This biological infrared imaging system offers a large detection depth, and the images provide not only information about the organism's internal structure but also metabolic information.

[0008] The technical solution adopted in this invention is: a wireless infrared quantum dot light-emitting diode, comprising an infrared quantum dot light-emitting part and an electromagnetic induction energy pumping part; The infrared quantum dot luminescent component includes a quantum dot luminescent layer, an electron transport layer, a hole transport layer, a cathode, an anode, a coating layer, and a current loop; The cathode is a metal electrode located below the electron transport layer; the anode is a metal electrode located above the hole transport layer; electrons and holes are injected into the cathode and anode, respectively; the cladding layer is an insulating layer covering the outer surface of the light-emitting diode; the current loop is located above the cladding layer, and the cathode and anode are connected by a metal loop along the surface of the cladding layer; the electron transport layer has n-type characteristics, transporting electrons injected from the cathode to the quantum dot light-emitting layer; the hole transport layer has p-type characteristics, transporting holes injected from the anode to the quantum dot light-emitting layer; the electron transport layer and the hole transport layer are matched with the conduction band bottom and valence band top of the quantum dot light-emitting layer; The electromagnetic induction energy pumping part is composed of a high-frequency coil, which is a coil composed of several turns of metal wire. An alternating current is passed through the high-frequency coil, and a time-varying electromagnetic field is generated through electromagnetic induction. The time-varying electromagnetic field passes through the current loop of the infrared quantum dot light-emitting diode, exciting the induced current, and driving the quantum dot light-emitting diode to emit infrared rays through the induced current. The quantum dot light-emitting layer is composed of semiconductor quantum dots with a band gap of less than 0.8 eV, and the corresponding electroluminescence wavelength is greater than 1 μm. This light has sufficient penetration depth into living organisms. The wireless infrared quantum dot light-emitting diode is smaller than 100 μm in size, making it possible to inject it into living organisms.

[0009] Furthermore, the quantum dot light-emitting layer is a PbS quantum dot, a PbSe quantum dot, or a graphene quantum dot.

[0010] Furthermore, the cathode and anode are connected by a multi-turn metal wire to increase the induced electromotive force and induced current generated in the electrical circuit of the light-emitting diode.

[0011] Furthermore, the current frequency of the high-frequency coil needs to be greater than 500MHz so that the induction coil can generate sufficient current in the light-emitting diode circuit and produce infrared radiation.

[0012] Furthermore, the electron transport layer and hole transport layer are prepared using a core-shell epitaxy method, such as PbSe / PbS core-shell or InP / ZnSe core-shell, to meet the requirements of micro-sized light-emitting diodes.

[0013] A biological detection and imaging system based on the above-mentioned wireless infrared quantum dot light-emitting diode includes an electromagnetic induction energy pumping part, an infrared quantum dot light-emitting part, and an infrared image acquisition part. The infrared electroluminescent component is dispersed into a solution and injected into the organism; An alternating current is passed through the high-frequency coil of the electromagnetic induction energy pump section to generate a time-varying electromagnetic field. The time-varying electromagnetic field penetrates the organism and excites the infrared electroluminescent part in the organism to emit infrared rays. The infrared image acquisition section acquires infrared signals emitted by the infrared electroluminescent part of the organism through an infrared camera, forming a biological infrared image that contains both structural and metabolic information.

[0014] Unlike conventional quantum dot light-emitting diodes, this invention does not have an external power supply between the cathode and anode. Instead, the cathode and anode are directly connected through a metal layer to form an electrical circuit. An insulating coating layer is placed outside the quantum dot light-emitting diode, and metal electrode lines cross the coating layer to connect the cathode and anode, preventing the electrical circuit from mistakenly injecting charge carriers into the light-emitting diode.

[0015] This invention also proposes a non-destructive biological infrared detection and imaging system. Wireless infrared quantum dot light-emitting diode (LED) particles are dispersed in a solution and then injected into the blood vessels of a living organism, entering the body through blood circulation. An alternating current is applied to an external induction coil to generate a time-varying electromagnetic field. Because this time-varying electromagnetic field has a relatively long wavelength (≥10 cm), it can penetrate into the biological body. This time-varying electromagnetic field induces a current in the wireless infrared quantum dot LED circuit inside the organism through electromagnetic induction, generating infrared radiation. Due to the strong penetrating power of infrared radiation into living organisms, the infrared energy radiated by the wireless infrared quantum dot LED passes through the organism and is received by an infrared camera, forming an infrared image.

[0016] Existing wireless light-emitting diodes (LEDs) are relatively large, on the centimeter scale. Furthermore, existing LEDs use conventional LEDs, emitting visible light and are only used for demonstrating physical principles. This invention builds upon this by miniaturizing the LED using colloidal quantum dots, reducing its size to less than 100 μm. The bandgap of the quantum dots is controlled to emit infrared light that can penetrate biological organisms. These tiny quantum dots are injected into the organism, and a time-varying electromagnetic field excites them to emit infrared light within the organism, allowing for the acquisition of infrared images of the organism.

[0017] The beneficial effects of this invention are: (1). This invention proposes a wireless infrared quantum dot light-emitting diode and a non-destructive biological detection and imaging system. The quantum dot light-emitting diode is injected into the biological body as tiny particles, and then an external electromagnetic field is used to excite the current, generating infrared radiation from the biological body. Compared with existing methods of external infrared light source irradiation and infrared camera image capture, it avoids the energy loss caused by infrared rays entering the biological body from the outside, so the captured infrared image has a greater penetration depth.

[0018] (2). This invention proposes a wireless infrared quantum dot light-emitting diode and a non-destructive biological detection imaging system. The quantum dot light-emitting diode particles enter the circulatory system of a living organism through the blood, and the particle concentration is related to metabolism. Compared with existing in vitro illumination infrared images, the infrared images obtained by this invention not only carry information about the internal structure of the organism but also reflect metabolic information.

[0019] (3) This invention proposes a wireless infrared quantum dot light-emitting diode and a non-destructive biological detection imaging system. It uses a time-varying electromagnetic field as the energy pump source, and the light-emitting diode generates electroluminescence through electromagnetic induction. Most existing infrared luminescent biofluorescence imaging systems use short-wavelength light as the energy pump source, obtaining infrared radiation through photoluminescence. Therefore, compared with infrared luminescent biofluorescence imaging, the infrared image obtained by this invention has a greater penetration depth and higher brightness. Attached Figure Description

[0020] Figure 1 A schematic diagram of ultrasound imaging of a living organism; Figure 2 This is a schematic diagram of X-ray imaging of a biological organism. Figure 3 This is a schematic diagram of a typical infrared biological imaging system; Figure 4 This is a schematic diagram of the wireless infrared quantum dot light-emitting diode of the present invention; Figure 5 This is a schematic diagram of the infrared biological imaging system of the present invention; In the diagram, 1. Organism; 2. Coupled liquid; 3. Ultrasonic transducer; 4. Transmitter; 5. Pulse generator; 6. Scan generator; 7. Receiver; 8. Image display terminal; 9. X-ray source; 10. X-ray detector; 11. Infrared source; 12. Infrared irradiation; 13. Infrared camera; 14. High-frequency coil; 15. Time-varying electromagnetic field; 16. Quantum dot emitting layer; 17. Electron transport layer; 18. Hole transport layer; 19. Cathode; 20. Anode; 21. Coating layer; 22. Current loop; 23. Infrared radiation. Detailed Implementation

[0021] The present invention will now be described in detail. This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0022] like Figure 4 As shown, a wireless infrared quantum dot light-emitting diode includes the following components: The first part is the quantum dot infrared light-emitting section. This part includes a quantum dot light-emitting layer 16, which is composed of semiconductor quantum dots with a band gap of less than 0.8 eV, such as PbS quantum dots, PbSe quantum dots, graphene quantum dots, etc.; an electron transport layer 17, which has n-type characteristics, transports electrons injected from the cathode 19 to the quantum dot light-emitting layer 16; a hole transport layer 18, which is used to transport holes injected from the anode 20 to the quantum dot light-emitting layer 16. Electrons and holes are injected from the cathode 19 and anode 20, respectively. A cladding layer 21 forms an insulating layer on the surface of the light-emitting diode. A current loop 22 connects the cathode 19 and anode 20 along the surface of the cladding layer 21 via a metal loop.

[0023] The second part is the energy pumping section. Since the quantum dot infrared emitting part of the first part has no energy source, it needs to be excited to emit light by an external pumping energy. It contains a high-frequency coil 14, which is energized with high-frequency alternating current to generate a time-varying electromagnetic field 15.

[0024] like Figure 5 As shown, a non-destructive biological detection and imaging system based on the aforementioned wireless infrared quantum dot light-emitting diode (LED) is described. Wireless infrared quantum dot LED particles are dispersed in a solution and then injected into a biological body 1. An alternating current is applied to a high-frequency coil 14 outside the biological body, generating a time-varying electromagnetic field 15. This time-varying electromagnetic field penetrates into the biological body, inducing a current in the wireless infrared quantum dot LED circuit inside the body through electromagnetic induction, generating infrared radiation 23. Because infrared radiation has strong penetrating power into biological bodies, the infrared energy radiated by the wireless infrared quantum dot LED passes through the biological body and is received by an infrared camera 13, forming an infrared image.

[0025] The fabrication process of the aforementioned wireless infrared quantum dot light-emitting diode is as follows: 1. Preparation of quantum dot semiconductor materials. These quantum dots need to have a small energy band gap to enable them to produce infrared electroluminescence. Typical materials include PbS and PbSe quantum dots. Taking PbSe quantum dots as an example, their preparation method is as follows: a) Prepare a precursor solution by mixing 660 mg / 3 mmol PbO powder, 8.5 mL / 26.4 mmol oleic acid, and 8.5 mL octadecene.

[0026] b) The above precursor solution was filtered three times under nitrogen atmosphere to remove excess oxygen from the solution. It was then heated to 150°C under argon atmosphere to form a pale yellow lead oleate solution. The solution was then vacuum-pressurized for 1 hour (<13 Pa) to remove impurities. c) The temperature of the lead oleate solution was gradually increased to 120°C, and 300 µL of diphenylphosphine and 9 mL of TOP-Se precursor solution were rapidly injected under nitrogen atmosphere. The resulting mixture was then gradually cooled to obtain PbSe quantum dots.

[0027] 2. Fabrication of epitaxial layers using a core-shell structure. To form the electron transport layer and hole transport layer of a light-emitting diode (LED), this invention proposes to construct these functional layers using a core-shell structure epitaxy. A typical structure is a PbSe / PbS core-shell epitaxy, the fabrication process of which is as follows: a) Dissolve 2.3 mL of 95% trimethylsilylsulfide in 5 mL of hexane, and mix it with the previously prepared PbSe quantum dot solution at a 1:1 ratio; b) The mixed solution was heated to 150°C under an inert gas atmosphere and reacted for 15 minutes to allow sufficient S to permeate into the PbSe quantum dots, forming a PbSe / PbS core-shell structure. The core-shell structured quantum dots were then washed with hexane, centrifuged, and dried.

[0028] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A wireless infrared quantum dot light-emitting diode, characterized in that: It includes an infrared quantum dot light-emitting part and an electromagnetic induction energy pumping part; The infrared quantum dot luminescent component includes a quantum dot luminescent layer, an electron transport layer, a hole transport layer, a cathode, an anode, a coating layer, and a current loop; The cathode is a metal electrode located below the electron transport layer; the anode is a metal electrode located above the hole transport layer; electrons and holes are injected into the cathode and anode, respectively; the cladding layer is an insulating layer covering the outer surface of the light-emitting diode; the current loop is located above the cladding layer, and the cathode and anode are connected by a metal loop along the surface of the cladding layer; the electron transport layer has n-type characteristics, transporting electrons injected from the cathode to the quantum dot light-emitting layer; the hole transport layer has p-type characteristics, transporting holes injected from the anode to the quantum dot light-emitting layer; the electron transport layer and the hole transport layer are matched with the conduction band bottom and valence band top of the quantum dot light-emitting layer; The electromagnetic induction energy pumping part is composed of a high-frequency coil, which is a coil composed of several turns of metal wire. An alternating current is passed through the high-frequency coil, and a time-varying electromagnetic field is generated through electromagnetic induction. The time-varying electromagnetic field passes through the current loop of the infrared quantum dot light-emitting diode, exciting the induced current, and driving the quantum dot light-emitting diode to emit infrared rays through the induced current. The quantum dot light-emitting layer is composed of semiconductor quantum dots with a band gap of less than 0.8 eV, and the corresponding electroluminescence wavelength is greater than 1 μm; The wireless infrared quantum dot light-emitting diode has a size of less than 100 μm.

2. The wireless infrared quantum dot light-emitting diode according to claim 1, characterized in that: The quantum dot luminescent layer is a PbS quantum dot, a PbSe quantum dot, or a graphene quantum dot.

3. A wireless infrared quantum dot light-emitting diode according to claim 2, characterized in that: The cathode and anode are connected by a multi-turn metal wire.

4. A wireless infrared quantum dot light-emitting diode according to claim 3, characterized in that: The current frequency of the high-frequency coil needs to be greater than 500MHz.

5. A wireless infrared quantum dot light-emitting diode according to claim 4, characterized in that: The electron transport layer and hole transport layer are prepared using a core-shell epitaxy method.

6. A biological detection imaging system based on the wireless infrared quantum dot light-emitting diode as described in claim 1, 2, 3, 4 or 5, characterized in that: It includes an electromagnetic induction energy pumping section, an infrared quantum dot light-emitting section, and an infrared image acquisition section; The infrared electroluminescent component is dispersed into a solution and injected into the organism; An alternating current is passed through the high-frequency coil of the electromagnetic induction energy pump section to generate a time-varying electromagnetic field. The time-varying electromagnetic field penetrates the organism and excites the infrared electroluminescent part in the organism to emit infrared rays. The infrared image acquisition section acquires infrared signals emitted by the infrared electroluminescent part of the organism through an infrared camera, forming a biological infrared image that contains both structural and metabolic information.

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