Photoelectric memory based on organic polymer and fluorinated perovskite material and preparation method thereof

Abstract

The invention provides a photoelectric memory based on an organic polymer and a fluorinated perovskite material and a preparation method, the photoelectric memory is based on a bottom gate bottom contact field effect transistor structure, the memory comprises a gate layer, a dielectric layer, a source and drain layer and an active layer from bottom to top, the gate layer is made of silicon, the dielectric layer is made of silicon dioxide, and the active layer is made of silicon oxide. The source electrode and the drain electrode are made of gold, and the active layer is selected from one or more of PDVT-10, P (NDI2OD-T2) and a perovskite material which is subjected to surface ligand engineering treatment, namely fluoridation. The organic polymer with good electrical performance and the perovskite material with good optical performance are selected to be combined, so that the photoelectric memory shows good electrical performance and good time retention performance, and a high current ratio and high data retention capacity can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic information materials and components, and in particular to a photoelectric storage device based on an organic polymer and a fluorinated perovskite material and a preparation method thereof. Background Art

[0002] At present, the wave of science and technology is surging, and the rapid development of technology is like a powerful driving force, prompting more and more electronic devices to enter the public's vision at an unprecedented speed. From the smartphones that people cannot live without in their daily lives, their functions are constantly upgraded, covering multiple fields such as high-definition camera, virtual reality experience, instant messaging, etc., to various sensors and controllers in smart home control systems, they are like invisible housekeepers in the home environment, accurately sensing and regulating indoor temperature and humidity, light brightness, and electrical appliance operation status; to the automated monitoring equipment on the industrial production line, real-time feedback of equipment operation parameters to ensure the efficiency and accuracy of the production process. In this system of various electronic devices, memory has undoubtedly become a vital core component. It is like the "memory center" of electronic devices, shouldering the heavy responsibility of data storage, fast reading and writing, and directly determining the smoothness of the device's operation, response speed and multi-tasking processing capabilities. In this context, memory, as the key underlying supporting technology of electronic devices, naturally became one of the research hotspots that both scientific research and industry pay attention to.

[0003] Compared with traditional memory, organic field-effect transistor memory has attracted more and more attention from researchers due to its high mobility and good stability. Although organic field-effect transistor memory has shown great potential, it is still in the technical breakthrough stage and faces many challenges such as the delicate balance between carrier mobility and storage stability, short data retention time, and large-scale industrialization cost control. Summary of the invention

[0004] In view of the above problems, the present invention proposes a photoelectric memory device based on organic polymer and fluorinated perovskite material and a preparation method thereof. The device can realize the storage function of the memory device and has a higher switching current ratio and a longer data retention time.

[0005] The present invention proposes an optoelectronic memory based on an organic polymer and a fluorinated perovskite material, which is based on a bottom-gate bottom-contact field effect transistor structure. The memory comprises from bottom to top: a gate layer, a dielectric layer, a source and a drain layer, and an active layer. The gate layer material is silicon, the dielectric layer material is silicon dioxide, the source and the drain material are gold, and the active layer is selected from one or more of PDVT-10, P(NDI2OD-T2), and a perovskite material that has been subjected to surface ligand engineering treatment, i.e., fluorinated.

[0006] Furthermore, the PDVT-10 material is a P-type organic polymer, also known as a hole-transporting polymer, with holes as the conductive carriers; P(NDI2OD-T2) is an N-type polymer, also known as an electron-transporting polymer, with electrons as the conductive carriers; the perovskite material is fluorinated using PFOA, and PFOA displaces oleic acid and oleylamine and binds to the surface of the perovskite material.

[0007] Furthermore, the working principle of the optoelectronic memory is as follows: The organic polymer and the fluorinated perovskite material are combined as the active layer of the optoelectronic memory. When light irradiates the active layer of the device, carriers, namely holes and electrons, are generated in the perovskite material. The carriers are trapped in the perovskite material, thereby increasing the current after illumination. As the illumination is removed, due to the energy level relationship, the carriers will flow to the organic polymer. However, since the perovskite material after surface ligand engineering, i.e., fluorination treatment, will retain the holes in the perovskite material, the current can be retained even after the illumination is removed and will not return to the original state.

[0008] The present invention also provides a method for preparing the above-mentioned optoelectronic memory based on an organic polymer and a fluorinated perovskite material. The method uses physical vapor deposition to prepare a bottom-gate bottom-contact field-effect transistor, which specifically includes: First, a gate layer is prepared. Secondly, a silicon dioxide dielectric layer is prepared on the gate layer using thermal oxidation. Then, a gold thin film is deposited on the above dielectric layer using physical vapor deposition, and the source and drain are patterned. Lithography technology is used to determine the positions and shapes of the source and drain. Then, the unnecessary metal parts are removed through an etching process. Finally, in an environment of pure nitrogen, the material is dissolved in chloroform by spin coating, and the solution is uniformly spread on the substrate by high-speed rotation. After the solvent evaporates, an active layer thin film is obtained. The obtained active layer thin film is uniform, and the film thickness is 20 nm.

[0009] An optoelectronic memory and a preparation method based on an organic polymer and a fluorinated perovskite material proposed by the present invention. The active layer of the memory selects PDVT-10, P(NDI2OD-T2), and the perovskite material after surface ligand engineering treatment, i.e., fluorination. Among them, the PDVT-10 material is a P-type organic polymer, and P(NDI2OD-T2) is an N-type polymer. The perovskite material is fluorinated using PFOA, and PFOA displaces oleic acid and oleylamine and binds to the surface of the perovskite material, which can effectively improve the problem that the bond force between oleic acid, oleylamine and the surface of the perovskite material is weak and easy to fall off from the surface of the perovskite material to form vacancies, resulting in the aggregation and degradation of the perovskite material. By selecting an organic polymer with good electrical properties and a perovskite material with good optical properties as the main materials, the optoelectronic memory exhibits good electrical properties and good time retention performance, and can achieve a high current ratio and a high data retention ability. Brief Description of the Drawings

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0011] Figure 1 It is a schematic structural diagram of an optoelectronic memory based on a mixture of an organic polymer and a perovskite material after surface ligand engineering treatment provided by an embodiment of the present invention. Among them, (a) is the front view, (b) is the left view, and (c) is the top view;

[0012] Figure 2 It is a schematic diagram of the working principle of the optoelectronic memory provided by an embodiment of the present invention. Among them, (a) is a schematic diagram of device performance testing, and (b) is a schematic diagram of the device working principle;

[0013] Figure 3 It is an absorption spectrum diagram of the perovskite material after surface ligand engineering treatment provided by an embodiment of the present invention;

[0014] Figure 4 It is an electrical performance test diagram of the P-type polymer optoelectronic memory provided by an embodiment of the present invention;

[0015] Figure 5 It is a retention time performance test diagram of the P-type polymer optoelectronic memory provided by an embodiment of the present invention;

[0016] Figure 6 It is an electrical performance test diagram of the N-type polymer optoelectronic memory provided by an embodiment of the present invention;

[0017] Figure 7 It is a retention time performance test diagram of the N-type polymer optoelectronic memory provided by an embodiment of the present invention. Detailed Embodiments

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0019] An optoelectronic memory based on an organic polymer and a fluorinated perovskite material proposed by the present invention is based on a bottom-gate bottom-contact field-effect transistor structure, and its structure is as Figure 1As shown, where (a) is the front view, (b) is the left view, and (c) is the top view. The memory includes, from bottom to top: a gate layer, a dielectric layer, a source and drain layer, and an active layer. The material of the gate layer is silicon, the material of the dielectric layer is silicon dioxide, the material of the source and drain is gold, and the active layer is selected from one or more of PDVT-10, P(NDI2OD-T2), and perovskite materials after surface ligand engineering treatment, i.e., fluorination.

[0020] Among them, the PDVT-10 material is a P-type organic polymer, also known as a hole-transporting polymer, and holes are the conductive carriers; P(NDI2OD-T2) is an N-type polymer, also known as an electron-transporting polymer, and electrons are the conductive carriers. Since the commonly used oleic acid and oleylamine are prone to fall off from the surface of the perovskite material due to weak bonding force with the perovskite material surface, forming vacancies, which leads to the aggregation and degradation of the perovskite material, and this has a significant impact on the optoelectronic properties of the perovskite material. Therefore, in the present invention, surface ligand engineering is adopted, and PFOA is used to fluorinate the perovskite material. PFOA displaces oleic acid and oleylamine and binds to the surface of the perovskite material, which can effectively improve the above problems.

[0021] Figure 2 It is a schematic diagram of the working principle of the optoelectronic memory. Among them, (a) is a schematic diagram of device performance testing, and (b) is a schematic diagram of the device working principle. The organic polymer has good electrical properties, such as a high current on-off ratio and high mobility. The perovskite material has good optical properties and can have a good response to wavelengths within the absorption range. When the two are mixed to form the active layer of the device, when light irradiates the active layer of the device, carriers (holes and electrons) are generated in the perovskite material, and the carriers are trapped in the perovskite material, thereby increasing the current after illumination. At this time, it can be considered that the data is in the stored state in the device. As the light is removed, due to the energy level relationship, the carriers will flow to the organic polymer, so the stored data will be lost. However, due to the perovskite material after surface ligand engineering (fluorination) treatment, the holes will be retained in the perovskite material, so that even when the light is removed, there is still current and it does not return to the original state. Therefore, the retention time performance of the optoelectronic memory in this embodiment is excellent.

[0022] The present invention also provides a method for preparing the above-mentioned optoelectronic memory based on an organic polymer and a fluorinated perovskite material. The method uses physical vapor deposition to prepare a bottom-gate bottom-contact field-effect transistor, which specifically includes: first, preparing a gate layer; second, preparing a silicon dioxide dielectric layer on the gate layer by thermal oxidation; then, depositing a gold thin film on the dielectric layer by physical vapor deposition, and patterning the source and drain electrodes to determine the positions and shapes of the source and drain electrodes by lithography technology; then, removing the unnecessary metal parts through an etching process; finally, in an environment of pure nitrogen, by spin coating, dissolving the material in chloroform, and spinning at high speed to make the solution spread evenly on the substrate, and obtaining an active layer thin film after the solvent volatilizes. The obtained active layer thin film is uniform and has a film thickness of 20 nm.

[0023] The present invention provides a light source through a monochromator instrument, irradiates the device with a wavelength within the absorption range of the perovskite material, and measures the relationship between the current value of the device after irradiation and time. Figure 3 It is the absorption spectrum diagram of the perovskite material after surface ligand engineering (fluorination) treatment used in the present invention. Since light irradiation is required for testing, an appropriate light irradiation wavelength needs to be selected according to the obtained spectrum diagram. In this example, a wavelength of 430 nm is selected.

[0024] In Example 1, the organic polymer used is the P-type polymer PDVT-10. The prepared optoelectronic memory device is tested with monochromatic light with a wavelength of 430 nm for 10 s, and then the light irradiation is removed and the test continues. Since the valence band value and conduction band value of the fluorinated perovskite material move in the positive direction, which is not conducive to the movement of holes, the holes are trapped in the device, that is, the data is saved. The test results are as Figure 4 and Figure 5 shown.

[0025] Figure 4 shows the electrical performance characteristics of the P-type polymer optoelectronic memory in the present embodiment in the dark state and the light irradiation state. Due to the light irradiation and the response of the perovskite to the light irradiation, the current value of the device is increased. By calculating the obtained current value and the gate voltage value, the current on-off ratio of the device can reach 10 6 , which is a relatively good value.

[0026] Figure 5 This is the retention ability test diagram of the P-type polymer optoelectronic memory in the present embodiment. The device is irradiated with light with a wavelength of 430 nm for 10 s, and then the light irradiation is removed. The current will decrease but will not drop to the original state, indicating that the data can be saved in the device and has good data retention ability.

[0027] In Example 2, the polymer used is the N-type polymer P(NDI2OD-T2), the wavelength used is 430 nm, the illumination time is 10 s, and the illumination is removed and the test continues. Since the valence band value and conduction band value of the fluorinated perovskite material shift in the positive direction, which is beneficial to the movement of electrons, it is difficult to preserve the data when electrons escape from the device. The test results are as Figure 6 and Figure 7 shown.

[0028] Figure 6 Figure shows the electrical performance characteristics of the N-type polymer optoelectronic memory of this example in the dark state and the illuminated state. Due to illumination, the perovskite responds to illumination, and the current value of the device after illumination is increased. By calculating the transfer curve of the device, the current on-off ratio of the device is 10 3 .

[0029] Figure 7 Figure shows the retention ability test chart of the N-type polymer optoelectronic memory of this example. The device is illuminated for 10 s under illumination with a wavelength of 430 nm, and then the illumination is removed. The current value drops rapidly and quickly returns to the original level, indicating that it is difficult to store electrons in the device. Once the illumination is removed, the electrons quickly run from the perovskite material to the polymer material, and the current value drops rapidly, indicating that it is difficult to store data.

[0030] From the above results, it can be seen that using the P-type polymer and the fluorinated perovskite material as the active layer materials can enable the optoelectronic memory to have a higher current ratio and better data retention ability.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optoelectronic memory based on an organic polymer and a fluorinated perovskite material, characterized in that: The photoelectric memory is based on a bottom-gate bottom-contact field effect transistor structure. The memory includes from bottom to top: a gate layer, a dielectric layer, a source and drain layer, and an active layer. The gate layer material is silicon, the dielectric layer material is silicon dioxide, the source and drain materials are gold, and the active layer is selected from one or more of PDVT-10, P (NDI2OD-T2) and perovskite materials that have been subjected to surface ligand engineering treatment, i.e., fluorinated.

2. The optoelectronic memory according to claim 1, characterized in that: PDVT-10 material is a P-type organic polymer, also known as a hole transport polymer, with holes as conductive carriers; P(NDI2OD-T2) is an N-type polymer, also known as an electron transport polymer, with electrons as conductive carriers; the perovskite material is fluorinated with PFOA, and PFOA replaces oleic acid and oleylamine to combine with the surface of the perovskite material.

3. The optoelectronic memory according to claim 1, characterized in that: The working principle of the photoelectric memory is as follows: an organic polymer and a fluorinated perovskite material are combined together as the active layer of the photoelectric memory. When light is irradiated to the active layer of the device, carriers, namely holes and electrons, are generated in the perovskite material. The carriers are captured in the perovskite material, thereby increasing the current after light exposure. As the light is removed, due to energy level relationships, the carriers will flow to the organic polymer. However, since the perovskite material has undergone surface ligand engineering, namely fluorination treatment, the holes will be retained in the perovskite material, and thus the current can be retained without returning to the original state even if the light is removed.

4. A method for preparing an optoelectronic memory based on an organic polymer and a fluorinated perovskite material as claimed in any one of claims 1 to 3, characterized in that: The method comprises: first preparing a gate layer, secondly preparing a silicon dioxide dielectric layer on the gate layer by a thermal oxidation method, then depositing a gold film on the dielectric layer by a physical vapor deposition method, patterning the source and drain electrodes, determining the positions and shapes of the source and drain electrodes by a photolithography technique, then removing unnecessary metal parts by an etching process, and finally, dissolving the material in chloroform by a spin coating method in a pure nitrogen environment, rotating at a high speed to evenly spread the solution on a substrate, and obtaining an active layer film after the solvent evaporates, wherein the obtained active layer film is uniform and has a film thickness of 20 nm.

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