Bidirectional photoresponse transistor based on conjugated polymer ultrathin film
By using conjugated polymer ultrathin film and pyrrolopyrrolidone-based materials in bidirectional photoresponsive devices, the preparation limitations of multi-component and inorganic materials in the prior art are solved, and high-performance responses to different wavelengths of light are achieved and Low-cost preparation provides a technical foundation for miniaturization and integration.
Patent Information
- Application Number
- CN202411180132.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-27
- Publication Date
- 2024-12-13
AI Technical Summary
Existing bidirectional photoresponsive devices rely on multi-component materials and inorganic charge transport layers, limiting large-area preparation and cost-effectiveness, and inhibitory photoresponsiveness depends on electrical signal modulation to lead to computational delays.
Using a bidirectional photoresponsive transistor based on a conjugated polymer ultrathin film, the pyrrolopyrrodyldione-based conjugated polymer material is used as a photosensitive charge transport layer, combining silicon gate electrodes and gold source and drain electrodes to achieve positive light of different wavelengths. and negative responses, and the optical response polarity is adjusted by controlling the charge transport layer thickness.
The high performance of the preparation of bidirectional photoresponsive devices for single-component polymer semiconductor materials is achieved, which reduces costs, simplifies the production process, and provides a technical basis for miniaturization and integration.
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Figure CN119136564A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of photoelectric transistors, in particular to a bidirectional light-responsive transistor based on a conjugated polymer ultra-thin film. Background Art
[0002] Inhibitory photoresponse is an indispensable property for building neuromorphic visual sensors and all-optically driven optoelectronic systems. However, most reported optoelectronic devices only exhibit excitatory photoresponse. The realization of inhibitory photoresponse still relies on electrical signal modulation, which requires the addition of additional hardware and generates computational delays. Therefore, it is necessary to achieve all-optical modulation of excitatory and inhibitory behaviors through bidirectional photoresponse.
[0003] Traditional bidirectional photoresponsive devices are mostly constructed by heterojunctions composed of multi-component materials, and the construction of the charge transfer layer relies on inorganic materials, which will be limited by material availability and processing complexity, and is not conducive to large-scale preparation of devices. The versatility of polymer semiconductors in structural design and mechanical tolerance makes them more advantageous than inorganic systems, and they have excellent processing properties and are ideal for large-scale production. Therefore, bidirectional photoresponsive transistors based on polymer semiconductor materials have good application prospects. Summary of the invention
[0004] The purpose of the present invention is to provide a bidirectional light-responsive transistor based on a conjugated polymer ultra-thin film, so as to achieve positive and negative responses to two different wavelengths of light, respectively.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is:
[0006] A bidirectional photoresponsive transistor based on a conjugated polymer ultrathin film is characterized in that: the bidirectional photoresponsive transistor comprises a substrate as a gate electrode, and a gate insulating layer, a modification layer, and a photosensitive charge transport layer arranged layer by layer on the substrate, and a source electrode and a drain electrode are arranged on the photosensitive charge transport layer; the photosensitive charge transport layer is an ultrathin film with a film thickness of less than 10nm.
[0007] The bidirectional light-responsive transistor produces positive and negative responses to two different wavelengths of light, respectively. The specific working method is: an operating voltage is applied to the gate electrode and the drain electrode of the transistor. When the transistor is irradiated from top to bottom with light of one wavelength, the drain current of the transistor increases with the increase of the illumination time. When the illumination is stopped, the drain current decreases with the increase of time until it recovers to the initial value; when the transistor is irradiated from top to bottom with light of another wavelength, the drain current of the transistor decreases with the increase of the illumination time. When the illumination is stopped, the drain current recovers to a certain extent.
[0008] Furthermore, the photosensitive charge transport layer is a pyrrolopyrrole diketo-based conjugated polymer material, including but not limited to at least one of pyrrolopyrrole diketo-based conjugated polymer materials such as polythiophene-pyrrolopyrrole diketo modified with siloxane side chains, polythiophene vinylthiophene-pyrrolopyrrole diketo modified with siloxane side chains, polydithiophene-pyrrolopyrrole diketo modified with siloxane side chains, polythiophene-pyrrolopyrrole diketo, and polydithiophene-pyrrolopyrrole diketo.
[0009] Further: the gate electrode is silicon. The gate insulating layer includes but is not limited to at least one of SiO2, Al2O3, polystyrene (PS), polyvinyl pyrrolidone (PVP), and polymethyl methacrylate (PMMA). The modification layer includes but is not limited to at least one of octadecyltrichlorosilane, dodecanethiol, 1-decanethiol, octadecyldihydroxyethylamine oxide, and perfluoro(1-butenyl vinyl ether) polymer (CYTOP).
[0010] Furthermore, the source electrode and the drain electrode are Au electrodes.
[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0012] 1. The present invention realizes for the first time the preparation of bidirectional photoresponsive transistors using single-component polymer semiconductor materials, providing a new strategy for the preparation of high-performance bidirectional photoresponsive devices that can produce positive and negative responses to light of different wavelengths. Moreover, the fact that it is completely based on organic semiconductor materials also significantly increases the possibility of practical application in terms of low-cost preparation.
[0013] 2. The present invention realizes for the first time the control of the polarity of the device's response to light of the same wavelength by changing the thickness of the photosensitive charge transport layer, that is, when the thickness of the photosensitive charge transport layer is large, the device responds positively to light; when the thickness of the photosensitive charge transport layer drops below 10nm, the device responds negatively to light. This provides a new strategy for the preparation of bidirectional photoresponsive devices.
[0014] 3. The bidirectional photoresponsive transistor of the present invention has excellent photoresponsiveness and electrical properties, and the manufacturing method is simple and low-cost, and has good application prospects.
[0015] 4. The device structure of the present invention is simple, and provides an important device physics and technical foundation for realizing miniaturized, integrated and high-performance bidirectional photoresponsive devices. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a schematic structural diagram of a transistor device of the present invention;
[0017] Figure 2is the chemical structural formula of the donor-acceptor type conjugated polymer DPP-4Si in Example 1 of the present invention;
[0018] Figure 3 is the drain current (I) of the bidirectional photoresponsive transistor in Example 1 of the present invention in the dark and under 365 nm light irradiation. DS ) with gate voltage (V GS )’s variation curve ( Figure 3 (a)) and its response to 365nm light (R) as the gate voltage (V GS )’s variation curve ( Figure 3 (b) in the above);
[0019] Figure 4 is the drain current (I) of the bidirectional photoresponsive transistor in Example 1 of the present invention in the dark and under 254 nm light irradiation. DS ) with gate voltage (V GS )’s variation curve ( Figure 4 (a)) and its response to 254nm light (R) as the gate voltage (V GS )’s variation curve ( Figure 4 (b) in the above);
[0020] Figure 5 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V;
[0021] Figure 6 is the drain current (I) of the bidirectional photoresponsive transistor in Example 2 of the present invention in the dark and under 365 nm light irradiation. DS ) with gate voltage (V GS )’s variation curve ( Figure 6 (a)) and its response to 365nm light (R) as the gate voltage (V GS )’s variation curve ( Figure 6 (b) in the above);
[0022] Figure 7 is the drain current (I) of the bidirectional photoresponsive transistor in Example 2 of the present invention in the dark and under 254 nm light irradiation. DS ) with gate voltage (V GS )’s variation curve ( Figure 7 (a)) and its response to 254nm light (R) as the gate voltage (V GS )’s variation curve ( Figure 7 (b) in the above);
[0023] Figure 8 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V;
[0024] Fig. 9 The drain current (I DS ) with gate voltage (V GS )’s variation curve ( Fig. 9 (a)) and its response to 365nm light (R) as the gate voltage (V GS )’s variation curve ( Fig. 9 (b) in the above);
[0025] Fig.10 The drain current (I DS ) with gate voltage (V GS )’s variation curve ( Fig.10 (a)) and its response to 254nm light (R) as the gate voltage (V GS )’s variation curve ( Fig.10 (b) in the above);
[0026] Fig.11 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V;
[0027] Fig.12 The drain current (I DS ) with gate voltage (V GS )’s variation curve ( Fig.12 (a)) and its response to 365nm light (R) as the gate voltage (V GS )’s variation curve ( Fig.12 (b) in the above);
[0028] Fig.13 The drain current (I DS ) with gate voltage (V GS )’s variation curve ( Fig.13 (a)) and its response to 254nm light (R) as the gate voltage (VGS )’s variation curve ( Fig.12 (b) in the above);
[0029] Fig.14 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V. DETAILED DESCRIPTION
[0030] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.
[0031] The present invention uses a pyrrolopyrrole diketo conjugated polymer material as a photosensitive charge transport layer, including but not limited to at least one of pyrrolopyrrole diketo conjugated polymer materials such as polythiophene-pyrrolopyrrole diketo modified with siloxane side chains, polythiophene vinylthiophene-pyrrolopyrrole diketo modified with siloxane side chains, polydithiophene-pyrrolopyrrole diketo modified with siloxane side chains, polythiophene-pyrrolopyrrole diketo, and polydithiophene-pyrrolopyrrole diketo. Among them:
[0032] The preparation methods of polythiophene-pyrrolopyrrole dione modified with siloxane side chains, polythiophene vinylthiophene-pyrrolopyrrole dione modified with siloxane side chains, and polydithiophene-pyrrolopyrrole dione modified with siloxane side chains are shown in the reference: Wang X, Huang H, Gu K, et al. Modulating Aggregation Structure and Properties of Conjugated Polymers via Ester Additives[J]. Macromolecules, 2024.
[0033] Polythiophene-pyrrolopyrrole diketo and polydithiophene-pyrrolopyrrole diketo are commercially available.
[0034] Example 1
[0035] This embodiment provides a bidirectional light-responsive transistor, whose structure is as follows: Figure 1 As shown, the transistor includes a substrate as a gate electrode, and a gate insulating layer, a modification layer, and a photosensitive charge transport layer arranged layer by layer on the substrate, and a source electrode and a drain electrode are arranged on the photosensitive charge transport layer. Specifically, in this embodiment: the gate electrode is silicon, the gate insulating layer is SiO2, the modification layer is CYTOP, and the photosensitive charge transport layer is DPP-4Si (whose chemical structure is as follows Figure 2 As shown), the source electrode and the drain electrode are Au electrodes.
[0036] The bidirectional light-responsive transistor of this embodiment is manufactured as follows:
[0037] A silicon wafer with a SiO2 layer of about 300 nm thickness was taken, and the wafer was first cleaned with a mixed solution of concentrated sulfuric acid and hydrogen peroxide, then cleaned with deionized water, and then dried with a nitrogen stream. CYTOP was spin-coated on the surface as a modification layer with a thickness of about 10 nm.
[0038] DPP-4Si was dissolved in chloroform at a concentration of 1 mg / mL. In a glove box, the DPP-4Si solution was spin-coated on the modified layer at 3000 rpm for 40 s to obtain an ultrathin film with a thickness of about 8.4 nm as a photosensitive charge transport layer. It was then dried at room temperature in a vacuum oven without heating to remove the solvent. Subsequently, Au was thermally evaporated onto the photosensitive charge transport layer through a mask to form a source and drain electrode with a thickness of about 40 nm, where the length and width of the channel were 100 μm and 1000 μm, respectively.
[0039] The working mode of the bidirectional light-responsive transistor in this embodiment is: V is applied to the gate electrode and drain electrode of the transistor respectively. GS =-40V, V DS = -40V working voltage. When the transistor is irradiated from top to bottom with 254nm deep ultraviolet light in the day-blind zone (i.e., vertically irradiated from the photosensitive charge transfer layer to the substrate), the drain current of the transistor increases with the increase of illumination time, and when the illumination stops, the drain current decreases with the increase of time until it returns to the initial value; when the transistor is irradiated from top to bottom with 365nm long-wave ultraviolet light, the drain current of the transistor decreases with the increase of illumination time, and when the illumination stops, the drain current recovers to a certain extent, thereby achieving positive and negative responses to two different bands of ultraviolet light.
[0040] In the absence of light, the bidirectional photoresponsive transistor of this embodiment forms a conductive path in the channel between the source and drain electrodes by applying a negative voltage of -40V to the gate electrode, and then applies a negative voltage of -40V to the drain electrode to make the charges move in a directional manner to form a current. When 365nm long-wave ultraviolet light irradiates the conductive channel between the source and drain electrodes, the electrons in the valence band of the semiconductor are excited, thereby generating holes in the photosensitive charge transport layer. Due to the difference in energy levels, a Schottky barrier is formed at the interface between the Au electrode and the photosensitive charge transport layer. Holes are captured at the interface between the Au electrode and the photosensitive charge transport layer, thereby inhibiting the injection of holes into the Au electrode, causing the drain current of the transistor to decrease with the increase of the light exposure time, resulting in a negative photoresponse. When 254nm deep ultraviolet light in the day-blind zone illuminates the conductive channel between the source and drain electrodes, due to its greater energy, more holes are generated in the photosensitive charge transfer layer, which have sufficient energy to overcome the Schottky barrier, causing the drain current of the transistor to increase with the increase of light exposure time, resulting in a positive photoresponse.
[0041] like Figure 3 As shown in (a), the irradiation intensity for the bidirectional photoresponse transistor of this embodiment is 3.20 mW / cm 2 When exposed to 365nm long-wave ultraviolet light, the drain current (I DS ) is less than the drain current in the dark state, and the calculated responsivity decreases to less than 0 as the gate voltage changes from positive to negative (e.g. Figure 3 (b) shows a negative photoresponse. Figure 4 As shown in (a), the irradiation intensity of the bidirectional photoresponse transistor of this embodiment is 0.55 mW / cm 2 When the device is exposed to 254nm deep ultraviolet light in the solar blind zone, the drain current generated by the device is greater than the drain current in the dark state, and the responsivity calculated from this is greater than 0 (such as Figure 4 (b)), showing a positive photoresponse. Figure 5 The bidirectional photoresponse transistor prepared for this example was tested at an intensity of 3.20 mW / cm 2 The 365nm long-wave UV light and the intensity are 0.55mW / cm 2 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V, the device produces a negative light response to 365nm long-wave ultraviolet light and a positive light response to 254nm deep ultraviolet light in the day-blind zone.
[0042] Example 2
[0043] The structure, materials and preparation method of the bidirectional light-responsive transistor of this embodiment are the same as those of Embodiment 1, except that the modification layer is octadecyltrichlorosilane.
[0044] like Figure 6 As shown in (a), the irradiation intensity for the bidirectional photoresponse transistor of this embodiment is 3.20 mW / cm 2 When exposed to 365nm long-wave ultraviolet light, the drain current (I DS ) is less than the drain current in the dark state, and the calculated responsivity decreases to less than 0 as the gate voltage changes from positive to negative (e.g. Figure 6 (b) shows a negative photoresponse. Figure 7 As shown in (a), the irradiation intensity of the bidirectional photoresponse transistor of this embodiment is 0.55 mW / cm 2 When the device is exposed to 254nm deep ultraviolet light in the solar blind zone, the drain current generated by the device is greater than the drain current in the dark state, and the responsivity calculated from this is greater than 0 (such as Figure 7 (b)), showing a positive photoresponse. Figure 8 The bidirectional photoresponse transistor prepared for this example was tested at an intensity of 3.20 mW / cm 2 The 365nm long-wave UV light and the intensity are 0.55mW / cm 2 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V, the device produces a negative light response to 365nm long-wave ultraviolet light and a positive light response to 254nm deep ultraviolet light in the day-blind zone.
[0045] Comparative Example 1
[0046] The structure, materials and preparation method of the bidirectional light-responsive transistor of this comparative example are the same as those of Example 1, except that the thickness of the photosensitive charge transport layer is about 22.9 nm.
[0047] like Fig. 9 (a) and Fig.10 As shown in (a), the irradiation intensity of the bidirectional photoresponse transistor of this comparative example is 3.20 mW / cm 2 The 365nm long-wave UV light and the intensity are 0.55mW / cm 2 When the device is exposed to 254nm deep ultraviolet light in the solar blind zone, the drain current (I DS ) are greater than the drain current in the dark state, and the calculated responsivity is greater than 0 (such as Fig. 9 (b) and 10(b)), both exhibited positive photoresponse. Fig.11The bidirectional photoresponse transistor prepared for this comparative example was 2 The 365nm long-wave UV light and the intensity are 0.55mW / cm 2 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V. When the transistor is irradiated from top to bottom with 254nm solar blind zone deep ultraviolet light and 365nm long wave ultraviolet light, the drain current of the transistor increases with the increase of illumination time. When the illumination stops, the drain current decreases with the increase of time until it returns to the initial value. The device of this comparative example produces positive light response to both 365nm long wave ultraviolet light and 254nm solar blind zone deep ultraviolet light.
[0048] Comparative Example 2
[0049] The structure, materials and preparation method of the bidirectional light-responsive transistor of this comparative example are the same as those of Example 1, except that the thickness of the photosensitive charge transport layer is about 40.5 nm.
[0050] like Fig.12 (a) and Fig.13 As shown in (a), the irradiation intensity of the bidirectional photoresponse transistor of this comparative example is 3.20 mW / cm 2 The 365nm long-wave UV light and the intensity are 0.55mW / cm 2 When the device is exposed to 254nm deep ultraviolet light in the solar blind zone, the drain current (I DS ) are greater than the drain current in the dark state, and the calculated responsivity is greater than 0 (such as Fig.12 (b) and 13(b)), both exhibited positive photoresponse. Fig.14 The bidirectional photoresponse transistor prepared for this comparative example was 2 The 365nm long-wave UV light and the intensity are 0.55mW / cm 2 The drain current-time curve (I DS -Time curve), the operating voltage is V GS =-40V, V DS =-40V. When the transistor is irradiated from top to bottom with 254nm solar blind zone deep ultraviolet light and 365nm long wave ultraviolet light, the drain current of the transistor increases with the increase of illumination time. When the illumination stops, the drain current decreases with the increase of time until it returns to the initial value. The device of this comparative example produces positive light response to both 365nm long wave ultraviolet light and 254nm solar blind zone deep ultraviolet light.
[0051] In summary, the present invention prepares a bidirectional light-responsive transistor that is easy to miniaturize and integrate by reducing the thickness of the photosensitive charge transport layer, and the device has excellent charge transport performance. The above description is only an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film, characterized in that: The bidirectional light-responsive transistor comprises a substrate as a gate electrode, and a gate insulating layer, a modification layer, and a photosensitive charge transport layer which are arranged layer by layer on the substrate, and a source electrode and a drain electrode are arranged on the photosensitive charge transport layer; the photosensitive charge transport layer is an ultra-thin film with a film thickness of less than 10 nm.
2. The bidirectional photoresponsive transistor based on conjugated polymer ultra-thin film according to claim 1, characterized in that: The bidirectional photoresponse transistor generates positive and negative responses respectively to two different wavelengths of light.
3. The bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film according to claim 1 or 2, characterized in that: The bidirectional light-responsive transistor produces positive and negative responses to two different wavelengths of light respectively in the following working mode: an operating voltage is applied to the gate electrode and the drain electrode of the transistor, and when the transistor is irradiated from top to bottom with light of one wavelength, the drain current of the transistor increases with the increase of the illumination time, and when the illumination is stopped, the drain current decreases with the increase of time until it recovers to the initial value; when the transistor is irradiated from top to bottom with light of another wavelength, the drain current of the transistor decreases with the increase of the illumination time, and when the illumination is stopped, the drain current recovers to a certain extent.
4. The bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film according to claim 1 or 2, characterized in that: The photosensitive charge transport layer is a diketopyrrolopyrrole conjugated polymer material.
5. The bidirectional photoresponsive transistor based on conjugated polymer ultra-thin film according to claim 4, characterized in that: The photosensitive charge transport layer is at least one of polythiophene-pyrrolopyrrole diketon modified with siloxane side chains, polythiophene vinylthiophene-pyrrolopyrrole diketon modified with siloxane side chains, polydithiophene-pyrrolopyrrole diketon modified with siloxane side chains, polythiophene-pyrrolopyrrole diketon, and polydithiophene-pyrrolopyrrole diketon.
6. The bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film according to claim 1 or 2, characterized in that: The gate electrode is silicon.
7. The bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film according to claim 1 or 2, characterized in that: The gate insulating layer is at least one of SiO2, Al2O3, polystyrene, polyvinyl pyrrolidone, and polymethyl methacrylate.
8. The bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film according to claim 1 or 2, characterized in that: The modified layer is at least one of octadecyltrichlorosilane, dodecanethiol, 1-decanethiol, octadecyldihydroxyethylamine oxide and perfluoro(1-butenyl vinyl ether) polymer.
9. The bidirectional photoresponsive transistor based on a conjugated polymer ultra-thin film according to claim 1 or 2, characterized in that: The source electrode and the drain electrode are Au electrodes.