Quantum dot light emitting structure, method for improving quantum dot optical communication bandwidth and experimental method

Abstract

The application relates to the technical field of communication devices, in particular to a method for improving quantum dot optical communication bandwidth, a quantum dot light-emitting structure and an experimental method for improving quantum dot optical communication bandwidth, which comprises the following steps: S1, providing a light-emitting chip; and S2, setting quantum dot color conversion materials with preset parameters on the light-emitting path of the light-emitting chip, so that the light emitted by the light-emitting chip passes through the quantum dot color conversion materials. Based on the principle of fluorescence resonance energy transfer, the application selects appropriate quantum dot concentration, adds a polar solvent to the quantum dot solution to generate an energy acceptor, enhances the energy transfer between the energy acceptor and the perovskite quantum dot, accelerates the recombination rate of carriers, reduces the carrier lifetime, and improves the communication bandwidth and rate.

Description

Technical Field

[0001] This application relates to the field of communication device technology, and in particular to a method for improving the bandwidth of quantum dot optical communication, a quantum dot light-emitting structure, and an experimental method for improving the bandwidth of quantum dot optical communication. Background Technology

[0002] In the field of visible light communication (VLC), schemes using color-conversion materials to achieve optical communication have shown wide applicability. Visible light communication technology uses light-emitting devices to emit high-speed flashing signals to transmit information. At the receiving end, a photodetector receives the signal, and after encoding, modulation, and demodulation, the signal transmission between the LED signal transmitter and receiver is completed. Visible light communication technology can serve as a supplementary access method to current WiFi and fiber optic internet access. Furthermore, with increasingly scarce wireless spectrum resources, visible light spectrum resources are abundant, requiring no authorization for use, and can be freely used under electromagnetically restricted or electromagnetically sensitive conditions. In addition, visible light communication systems have extremely high confidentiality; as long as the transmission path of visible light is blocked, the signal cannot be transmitted normally. Most rooms can prevent the signal from propagating outwards, thus maintaining privacy.

[0003] However, in existing VLC solutions, the selection of QDs (Quantum Dots) as color conversion materials has not been systematically optimized and screened for applications in the communications field. Therefore, they exhibit relatively average bandwidth and speed, failing to adequately meet application requirements. With the increasing complexity of modern communication applications, such as underwater communication and communication in environments with electromagnetic interference, VLC demonstrates its strong applicability in these environments. However, this also further increases the demands on the communication performance of VLCs. Summary of the Invention

[0004] To address the current lack of optimization for quantum dot bandwidth performance and the shortcomings of existing quantum dot applications in the VLC field, this application provides a method for improving the bandwidth of quantum dot optical communication.

[0005] In a first aspect, this application provides a method for improving the bandwidth of quantum dot optical communication, comprising the following steps: A method for improving the bandwidth of quantum dot optical communication, comprising the following steps:

[0006] S1: Provides a light-emitting chip; and

[0007] S2: A quantum dot color conversion material with preset parameters is placed in the light output path of the light-emitting chip, so that the light emitted from the light-emitting chip passes through the quantum dot color conversion material.

[0008] The above-mentioned approach overcomes the limitations of existing technologies that only utilize quantum dot color conversion materials as wavelength conversion materials. Instead, it improves the bandwidth of quantum dot optical communication by adjusting the parameters of the quantum dot color conversion material 3. The method for improving the bandwidth of quantum dot optical communication provided in this application is based on the principle of fluorescence resonance energy transfer (FRET). By selecting an appropriate quantum dot concentration and adding a polar solvent to the quantum dot solution to generate an energy acceptor, the energy transfer between the energy acceptor and the perovskite quantum dot is enhanced, thereby accelerating the recombination rate of charge carriers and reducing the carrier lifetime, thus improving the communication bandwidth and speed.

[0009] In one embodiment, the quantum dot color conversion material is a quantum dot solution, which includes a dispersion and quantum dots dispersed in the dispersion. Passing the light beam emitted by the light-emitting chip through the quantum dot solution is simple, intuitive, and has a straightforward process, without the influence of environmental conditions on communication performance.

[0010] In one embodiment, the preset parameter is the solution concentration, which is between 0.02 and 40 mg / ml.

[0011] In one embodiment, the concentration of the solution is between 0.2 and 2 mg / ml.

[0012] In one embodiment, the quantum dot color conversion material is a quantum dot thin film.

[0013] In this embodiment, step S3 is further included: adding a polar solvent to the quantum dot solution to increase carrier recombination efficiency and reduce carrier lifetime by utilizing a non-radiative energy transfer mechanism. The polar solvent is selected from at least one of acetone, acetonitrile, ethanol, diethyl ether, butanone, chloroform, dichloromethane, phenol, and anisole.

[0014] Secondly, this application also provides a quantum dot light-emitting structure, which is manufactured by the method for increasing the bandwidth of quantum dot optical communication as described in any of the above claims.

[0015] Thirdly, this application also provides an experimental method for improving the bandwidth of quantum dot optical communication, which includes the following steps: constructing a visible light testing system, the visible light testing system including a light-emitting chip, a collimating lens, a focusing lens, a filter and a detector sequentially disposed on the optical path of the light-emitting chip, the visible light testing system also including a quantum dot color conversion material disposed between the light-emitting chip and the filter, wherein there are multiple sets of quantum dot color conversion materials, each set having different preset parameters, and one set of quantum dot color conversion materials is disposed between the collimating lens and the focusing lens at a time;

[0016] The communication parameters of the quantum dot color conversion material under different parameters are obtained from the detector; and

[0017] The set of quantum dot color conversion materials corresponding to the optimal communication parameters was obtained.

[0018] In one embodiment, the quantum dot color conversion material is a quantum dot solution, which includes a dispersion and quantum dots dispersed in the dispersion; the preset parameter is the solution concentration, which is between 0.02-40 mg / ml.

[0019] In summary, this application includes at least one of the following beneficial technical effects:

[0020] 1. The present application provides a mechanism based on fluorescence resonance energy transfer, which improves communication bandwidth and speed by selecting an appropriate quantum dot concentration and adding a polar solvent to the quantum dot solution to generate an energy acceptor, thereby enhancing the energy transfer between the energy acceptor and the perovskite quantum dots and accelerating the recombination rate of charge carriers, i.e. reducing the charge carrier lifetime.

[0021] 2. By changing the concentration or solvent parameters of the perovskite quantum dot solution, FRET can be enhanced, thereby achieving a near 100% increase in communication bandwidth and speed.

[0022] 3. By using a transparent container to hold a quantum dot solution, the light beam emitted by the light-emitting chip passes through the quantum dot solution. This method is simple, intuitive, and has a straightforward process, and is not affected by environmental conditions. Attached Figure Description

[0023] Figure 1 This is the visible light testing system provided in this application;

[0024] Figure 2 This is a -3dB bandwidth diagram of perovskite quantum dot solutions at different concentrations;

[0025] Figure 3 The graph shows the optical power output of perovskite quantum dot solutions of different concentrations.

[0026] Figure 4 This is the -3dB bandwidth diagram after adding a polar solvent to the quantum dot solution;

[0027] Figure 5 This is a schematic diagram illustrating the signal transmission rate when 55 microliters of ethanol are added to a quantum dot solution.

[0028] Explanation of reference numerals in the attached diagram: 1. Light-emitting chip; 2. Collimating lens; 3. Quantum dot color conversion material; 4. Focusing lens; 5. Filter; 6. Detector. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0030] Embodiment 1 of this application discloses a method for improving the bandwidth of quantum dot optical communication, including the following steps:

[0031] S1: Provides a light-emitting chip; and

[0032] S2: A quantum dot color conversion material with preset parameters is placed in the light output path of the light-emitting chip, so that the light emitted from the light-emitting chip passes through the quantum dot color conversion material.

[0033] The light-emitting chip can be a micro light-emitting diode or a laser diode. In this embodiment, the light-emitting chip is a laser diode.

[0034] In this embodiment, the quantum dot color conversion material is a quantum dot solution, which includes a dispersion and quantum dots dispersed in the dispersion.

[0035] In this embodiment, the preset parameter is the solution concentration, which is between 0.02 and 40 mg / ml. More preferably, the solution concentration is between 0.2 and 2 mg / ml.

[0036] The quantum dot material includes at least one of group II-IV, II-VI, II-V, III-V, III-VI, IV-VI, I-III-VI, II-IV-VI, and II-IV-V semiconductor compounds, or perovskite quantum dots. That is, any quantum dot can be used to improve its communication bandwidth using the above method. In this embodiment, the quantum dot is a perovskite quantum dot because perovskite quantum dots have a narrow full width at half maximum (FWHM), tunable wavelength, wide color gamut, high quantum yield, and short photoluminescence lifetime.

[0037] In this embodiment, step S3 is also included: adding a polar solvent to the vector dot solution to increase carrier recombination efficiency and reduce carrier lifetime by utilizing a non-radiative energy transfer mechanism.

[0038] In one embodiment, the polar solvent is selected from at least one of acetone, acetonitrile, ethanol, diethyl ether, butanone, chloroform, dichloromethane, phenol, and anisole. Analysis shows that the addition of the polar solvent acts as an energy acceptor in the quantum dot solution, providing additional carrier recombination channels and thus accelerating the carrier recombination rate, thereby reducing carrier lifetime and improving bandwidth. For the perovskite quantum dot CsPbBr3 in this example, adding a trace amount of ethanol allows it to form hydrogen bonds with the -NH2 groups in the quantum dot solution, acting as an energy acceptor and providing additional carrier recombination channels, accelerating carrier recombination within the perovskite quantum dot, shortening the carrier lifetime, and improving the -3dB bandwidth.

[0039] In other embodiments, the quantum dot color conversion material is a quantum dot thin film. The quantum dot thin film can be formed on the surface of the light-emitting chip, or it can be directly disposed on the light-emitting path of the light-emitting chip. The quantum dot thin film can also be prepared separately. The preparation method of the quantum dot thin film can refer to the preparation methods in the prior art. However, when the quantum dot thin film is used in a scheme to improve quantum dot optical communication, it is necessary to use a pre-optimized quantum dot solution and adjust the appropriate layer structure of the quantum dot film, including the film concentration and film thickness, so that when the laser beam is incident on the quantum dot film, it can also accelerate carrier recombination, reduce carrier lifetime, and thus improve the modulation bandwidth of the communication.

[0040] Secondly, this application also provides a quantum dot light-emitting structure, which is manufactured using the method described above for improving the bandwidth of quantum dot optical communication. Specifically, a quantum dot color conversion material with preset parameters is placed in the light-emitting path of the quantum dot. This material, by selecting an appropriate quantum dot concentration and adding a polar solvent to the quantum dot solution to generate an energy acceptor, enhances the energy transfer between the energy acceptor and the perovskite quantum dot, thereby accelerating the recombination rate of charge carriers and reducing the carrier lifetime, thus improving the communication bandwidth and speed.

[0041] Thirdly, this application also provides an experimental method for improving the bandwidth of quantum dot optical communication, which includes the following steps:

[0042] Step 1: Please refer to Figure 1A visible light testing system is constructed, comprising a light-emitting chip 1, a collimating lens 2, a focusing lens 4, a filter 5, and a detector 6 sequentially arranged along the optical path of the light-emitting chip 1. The system also includes quantum dot color conversion material 3 disposed between the light-emitting chip 1 and the filter 5. Multiple sets of quantum dot color conversion material 3 are used, each with different preset parameters. One set of quantum dot color conversion material 3 is placed between the collimating lens 2 and the focusing lens 4 at a time. The collimating lens 2 collimates the light beam emitted from the light-emitting chip 1 into parallel light, which is then focused by the focusing lens 4 and converged into the detector 6.

[0043] In this embodiment, the quantum dot color conversion material 3 is a quantum dot solution, which includes a dispersion and quantum dots dispersed in the dispersion; the preset parameter is the solution concentration, which is between 0.02-40 mg / ml.

[0044] Specifically, in this embodiment, different quantities of quantum dot particles were added to 10 cuvettes to obtain quantum dot solutions of different concentrations. In this embodiment, ten groups of perovskite quantum dot solutions with concentrations of 0.02 mg / ml, 0.05 mg / ml, 0.1 mg / ml, 0.2 mg / ml, 0.5 mg / ml, 1 mg / ml, 2 mg / ml, 10 mg / ml, 20 mg / ml, and 40 mg / ml were obtained and sealed in cuvettes.

[0045] A cuvette containing a quantum dot solution is placed between collimating lens 2 and focusing lens 4. The selected laser diode emits a laser wavelength of 450nm; that is, a combination of a 450nm laser diode and liquid perovskite quantum dot solution is used as the light source. The light-emitting chip can be driven by a bias converter.

[0046] Step 2: Obtain the communication parameters of the quantum dot color conversion material under different parameters from the detector 6. In this embodiment, the communication parameters refer to bandwidth and / or transmission rate.

[0047] Step 3: Determine the set of quantum dot color conversion materials corresponding to the optimal communication parameters. Frequency response, bandwidth characteristics, and luminescence properties of quantum dot solutions with different concentrations are obtained using detector frequency sweep testing, as shown below. Figure 2 and Figure 3 As shown, a quantum dot solution concentration of 0.5 mg / ml yields the highest optical modulation bandwidth and moderate luminescence performance. It should be noted that... Figures 2-5 In the diagram, the horizontal dashed line represents the -3dB line. Figure 2 This indicates that the frequency, i.e. the horizontal axis, is at its maximum only when the concentration line drops to -3dB, which is also the maximum bandwidth. Figure 3The left vertical axis and the square represent the -3dB bandwidth for different concentrations. Figure 3 The right vertical axis represents the optical output power corresponding to different concentrations of -3dB bandwidth. It can be seen that the optical output power is highest at a quantum dot solution concentration of 0.5 mg / ml.

[0048] Step 4: When the quantum dot color conversion material is a quantum dot solution, a polar solvent is added to the quantum dot solution corresponding to the optimal communication parameters to further optimize the communication performance of the perovskite quantum dots. The polar solvent is selected from at least one of the following: acetone, acetonitrile, ethanol, diethyl ether, butanone, chloroform, dichloromethane, phenol, and anisole. In this embodiment, the polar solvent is ethanol.

[0049] In this embodiment, a small amount of the polar solvent ethanol was added to a perovskite quantum dot solution with a concentration of 0.5 mg / ml. Representative experiments were conducted using 15 μL and 55 μL of ethanol, respectively, and the communication performance test results are shown below. Figure 4-5 As shown. BER is the bit error rate; at the same frequency, a lower bit error rate indicates better performance. FEC is forward error correction, and FEC limit is the threshold for forward error correction. When the bit error rate is below the forward error correction threshold, the set communication rate can be achieved through forward error correction.

[0050] Please see Figure 5 When the limit is reached, the quantum dots with added ethanol require a much higher speed than those without. It can be observed that adding 55 μL of ethanol to the solution resulted in approximately 116.4% improvement in communication bandwidth and speed, while simultaneously achieving approximately 89.4% improvement in transmission speed at the same bit error rate. Specifically, ten cuvettes containing a dispersion solution can be provided; in this embodiment, the dispersion solution is n-hexane solvent. It is understood that the dispersion solution is not limited to n-hexane.

[0051] The increase in communication bandwidth is calculated as follows: (363.68-168.03) / 168.03 = 116.4%, which means that the communication bandwidth growth rate of the maximum value compared to the minimum value is 116.4%.

[0052] Regarding transmission rate, the transmission rate of the light signal without the addition of the polar solvent ethanol is 660 Mbps, while the transmission rate with the addition of 55 μL of the polar solvent ethanol is 1250 Mbps, resulting in a growth rate of (1250-660) / 660 = 89.4%. The transmission rate is higher with 55 μL of polar solvent ethanol compared to 15 μL, meaning that the amount of polar solvent is also an important factor affecting the signal transmission rate.

[0053] Then, the light output from the laser pumps the perovskite quantum dots, and the light signal from the perovskite quantum dots is focused onto a high-sensitivity detector, which is an avalanche photodiode (APD), through a lens at the receiving end. At the same time, a 495nm long-pass filter 5 is placed in front of the APD to filter out the remaining blue light band from the LD.

[0054] The communication performance of ten groups of perovskite quantum dot solutions with different concentrations was tested, and the data results are shown in Table 1 below. The four columns of data in Table 1 represent the concentration of the quantum dot solution, the -3dB bandwidth, the output power, and the transmission rate, respectively.

[0055] Table 1

[0056]

[0057] As can be seen from the table above, when the concentration of the perovskite quantum dot solution is 0.5 mg / ml, the -3 dB bandwidth is the widest and the transmission rate is the highest.

[0058] In summary, this application proposes to effectively improve the communication bandwidth of quantum dots by changing the quantum dot concentration and solvent parameters, and based on the mechanism of fluorescence resonance energy transfer leading to a reduction in photoluminescence (PL) carrier lifetime. This opens up a promising avenue for improving the communication performance of quantum dots. The process of this invention is simple and easy to implement, and it further develops the visible light communication performance of perovskite quantum dots, providing guidance for realizing high-performance displays and multifunctional applications such as VLC.

[0059] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for improving the bandwidth of quantum dot optical communication, characterized in that, Includes the following steps: S1: Provides a light-emitting chip; S2: A quantum dot color conversion material with preset parameters is provided in the light output path of the light-emitting chip, so that the light emitted from the light-emitting chip passes through the quantum dot color conversion material. The quantum dot color conversion material is a quantum dot solution, and the quantum dot solution includes a dispersion liquid and quantum dots dispersed in the dispersion liquid. as well as S3: Adding a polar solvent to the quantum dot solution to increase carrier recombination efficiency and reduce carrier lifetime by utilizing a non-radiative energy transfer mechanism.

2. The method for improving the bandwidth of quantum dot optical communication according to claim 1, characterized in that, The preset parameter is the solution concentration, which is between 0.02 and 40 mg / ml.

3. The method for improving the bandwidth of quantum dot optical communication according to claim 2, characterized in that, The concentration of the solution is between 0.2 and 2 mg / ml.

4. The method for improving the bandwidth of quantum dot optical communication according to claim 1, characterized in that, The polar solvent is selected from at least one of the following: acetone, acetonitrile, ethanol, diethyl ether, butanone, chloroform, dichloromethane, phenol, and anisole.

5. A quantum dot light-emitting structure, characterized in that, The quantum dot light-emitting structure is manufactured by the method for improving the bandwidth of quantum dot optical communication as described in any one of claims 1-4.

6. An experimental method for improving the bandwidth of quantum dot optical communication, characterized in that, Includes the following steps: A visible light testing system is constructed, comprising a light-emitting chip, a collimating lens, a focusing lens, a filter, and a detector sequentially arranged in the optical path of the light-emitting chip. The visible light testing system also includes a quantum dot color conversion material disposed between the light-emitting chip and the filter. There are multiple sets of quantum dot color conversion materials, each set having different preset parameters. One set of quantum dot color conversion material is disposed between the collimating lens and the focusing lens at a time. The quantum dot color conversion material is a quantum dot solution, which includes a dispersion and quantum dots dispersed in the dispersion. as well as Adding polar solvents to quantum dot solutions can increase carrier recombination efficiency and reduce carrier lifetime by utilizing non-radiative energy transfer mechanisms. The communication parameters of the quantum dot color conversion material under different parameters are obtained from the detector; and The set of quantum dot color conversion materials corresponding to the optimal communication parameters was obtained.

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