Phototransistor of perovskite dielectric layer and preparation method

Abstract

The invention discloses a photoelectric transistor of a perovskite dielectric layer and a preparation method, the transistor is of a bottom gate structure, and the transistor comprises a gate electrode, a dielectric layer, a channel layer, a source electrode and a drain electrode; the dielectric layer is made of wide-band-gap organic and inorganic hybrid perovskite; the channel layer is an organic semiconductor; the channel layer is on the dielectric layer. The photoelectric transistor can be prepared by a simple solution spin coating method, the preparation process which can be implemented by only using a spin coater is simpler, and the photoelectric transistor can be compatible with a flexible substrate and is suitable for large-scale commercial application; at the same time, it can be detected at extremely low voltage (lt; 2V); the transistor has good universality and low-voltage operation characteristics, so that the transistor has a wide application prospect in the field of ultraviolet / deep ultraviolet photoelectric detection.

Description

Technical Field

[0001] The present invention belongs to the field of organic-inorganic hybrid perovskite field-effect transistors, and more specifically, relates to a field-effect transistor using perovskite as a dielectric layer. Background Art

[0002] Ultraviolet / Deep ultraviolet photodetectors are crucial in fields such as communication, missile warning, astronomy, weather prediction, fire detection, marine pollution monitoring, and biomedicine, and have received much attention in recent years. Among these detectors, phototransistors have advantages over photodiodes due to their signal amplification ability, low noise, and excellent switching characteristics. Most phototransistors rely on semiconductors with a bandgap greater than 3 eV as the channel layer to detect ultraviolet / deep ultraviolet light. These semiconductor materials mainly include metal oxides (such as Ga2O3, SnO x , IGZO) and III-V compounds (such as ZnSe, AlN, BN), etc. However, the preparation of these materials usually requires expensive equipment and strict conditions (such as vacuum or high temperature), which is not conducive to large-scale production and cost reduction.

[0003] In contrast, metal halide perovskites (MHPs) have a high absorption coefficient, and the prepared thin films can strongly absorb light even at very thin thicknesses. At the same time, their long carrier diffusion length helps efficient charge extraction and reduces losses. The solution-processable characteristics of MHPs greatly reduce the manufacturing cost and are suitable for large-scale production. By adjusting their components, the optical bandgap can be adjusted from 1.5 eV to above 3 eV, showing great potential in ultraviolet / deep ultraviolet phototransistors. However, using wide-bandgap MHPs as the transistor channel layer faces problems of charge injection and transport, and it is difficult for the device to obtain high performance, which limits their wide application in ultraviolet / deep ultraviolet phototransistors. Summary of the Invention

[0004] The object of the present invention is to overcome the above problems and provide a brand-new concept of phototransistor to achieve low-cost and efficient ultraviolet / deep ultraviolet light detection.

[0005] Therefore, in the first aspect, to solve the technical problems of the present invention, the following technical solutions are adopted: A phototransistor with a perovskite dielectric layer, characterized in that the transistor is a bottom-gate structure, and the transistor includes a gate electrode, a dielectric layer, a channel layer, a source electrode, and a drain electrode; the dielectric layer is a wide-bandgap organic-inorganic hybrid perovskite; the channel layer is an organic semiconductor; the channel layer is on the dielectric layer.

[0006] Further, the wide-bandgap organic-inorganic hybrid perovskite is a quasi-two-dimensional perovskite with a bandgap greater than 3.0 eV.

[0007] Further, the quasi-two-dimensional perovskite is A2MZ4 (A = (PEA) x (BA) y ; M = Pb x Sn y ; Z = Br x Cl y ; x + y = 1).

[0008] Further, the thickness range of the perovskite dielectric layer is 80 nm to 200 nm. If the dielectric layer is too thin, it is easy to cause a significant increase in leakage current, while if it is too thick, the capacitance will decrease, which will increase the working voltage to a certain extent, resulting in an increase in device power consumption.

[0009] Correspondingly, the present invention provides a method for preparing a perovskite dielectric layer phototransistor. The transistor is a bottom-gate structure, and the preparation method includes the following steps:

[0010] 1) Prepare a wide-bandgap organic-inorganic hybrid perovskite solution.

[0011] 2) Spin-coat the wide-bandgap organic-inorganic hybrid perovskite solution on a substrate with electrodes and perform low-temperature annealing to form a dielectric layer.

[0012] 3) Deposit an organic semiconductor on the dielectric layer to form a channel layer.

[0013] Further, the electrodes are a gate electrode, a source electrode, and a drain electrode.

[0014] Further, the electrode is a gate electrode, and a source electrode and a drain electrode are prepared on the channel layer.

[0015] Further, the wide-bandgap organic-inorganic hybrid perovskite is a quasi-two-dimensional perovskite with a bandgap greater than 3.0 eV.

[0016] Further, the quasi-two-dimensional perovskite is A2MZ4 (A = (PEA) x (BA) y ; M = Pb x Sn y ; Z = Br x Cl y ; x + y = 1).

[0017] Further, the method for depositing the channel layer is dry transfer. Dry transfer can protect the dielectric layer from solvent damage and resulting in leakage.

[0018] Further, the spin-coating speed of the perovskite precursor solution is 4000 - 6000 rpm, and the annealing temperature is 100 °C - 150 °C. If the spin-coating speed or annealing temperature deviates from the above range, it is easy to cause poor crystallinity of the perovskite film, resulting in breakdown phenomena during device operation.

[0019] The above technical solution has the following technical effects:

[0020] (1) The present invention proposes a perovskite dielectric layer phototransistor. Since current ultraviolet / deep ultraviolet light detection usually requires the preparation of wide-bandgap metal oxides or III-V compound semiconductors as channel layers to achieve, the preparation processes of these materials are costly and complex. The novel structure proposed by us can solve this problem. It can not only be prepared by a simple solution spin-coating method, but also operate normally at an extremely low voltage (<2V).

[0021] (2) The method for preparing the perovskite dielectric layer phototransistor provided by the present invention is simple. The perovskite dielectric layer only needs to be formed by spin-coating the corresponding solution followed by low-temperature annealing. The semiconductor layer is also formed into a film on the PDMS substrate by spin-coating and then transferred onto the perovskite dielectric layer. This preparation process that can be implemented only by using a single spin coater is simpler and can be compatible with flexible substrates, being suitable for large-scale commercial applications.

[0022] (3) The perovskite dielectric layer phototransistor provided by the present invention can be prepared in large areas, showing good universality and low-voltage operation characteristics, making it have broad application prospects in the field of ultraviolet / deep ultraviolet photodetection. Description of the Drawings

[0023] Figure 1 Schematic diagram of the perovskite dielectric layer phototransistor in Embodiment 1 of the present invention;

[0024] Figure 2 Transfer characteristic curve of the perovskite dielectric layer phototransistor in Embodiment 1 of the present invention;

[0025] Figure 3 Transfer characteristic curve of the perovskite dielectric layer phototransistor in Embodiment 1 of the present invention under ultraviolet light illumination;

[0026] Figure 4 Ultraviolet light response time diagram of the perovskite dielectric layer phototransistor in Embodiment 1 of the present invention;

[0027] Figure 5 Transfer characteristic curve of the perovskite dielectric layer phototransistor in Embodiment 2 of the present invention;

[0028] Figure 6 Transfer characteristic curve of the perovskite dielectric layer phototransistor in Embodiment 2 of the present invention under deep ultraviolet light illumination;

[0029] Figure 7 Deep ultraviolet light response time diagram of the perovskite dielectric layer phototransistor in Embodiment 2 of the present invention;

[0030] Figure 8 Flow chart for preparing a phototransistor with a perovskite dielectric layer in Embodiment 3 of the present invention. Detailed implementation manners

[0031] To more clearly illustrate the purpose and advantages of the present invention, the following embodiments will further describe the present invention in detail in conjunction with the accompanying drawings. The specific embodiments described below are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Embodiment 1

[0033] A phototransistor with a perovskite dielectric layer is provided. Using PEA2PbBr4 as the dielectric layer and an organic semiconductor without any light response, a phototransistor that responds to 405 nm ultraviolet light can be fabricated.

[0034] Refer to Figure 1 , a perovskite dielectric layer phototransistor, which includes a gate electrode (Si ++ ), a 140 nm perovskite dielectric layer (PEA2PbBr4), a 100 nm organic semiconductor channel layer (PDVT-10), and 100 nm source electrode (Ag) and drain electrode (Ag).

[0035] Refer to Figure 2 , for the electrical test of the perovskite dielectric layer phototransistor, it shows a good transistor transfer characteristic curve at room temperature, and the device can operate at a very low voltage (<2V).

[0036] Refer to Figure 3 and Figure 4 , it can be seen from the transfer characteristic curve under illumination that the perovskite dielectric layer phototransistor exhibits a strong light response behavior under the irradiation of 405 nm ultraviolet light with a light power density of 0.05 mW / cm 2 , and the device current increases with the increase of the illumination intensity; at the same time, the response rise time and decay time of the device are 22 ms and 23 ms respectively, showing sensitive light detection performance.

[0037] Embodiment 2

[0038] A phototransistor with a perovskite dielectric layer is provided. Taking PEA2PbCl4 as the dielectric layer as an example, using an organic semiconductor without any light response, a phototransistor that responds to 265 nm deep ultraviolet light can be fabricated.

[0039] A perovskite dielectric layer phototransistor, which includes a gate electrode (Si ++) a 80-nm perovskite dielectric layer (PEA2PbCl4), a 100-nm organic semiconductor channel layer (PDVT-10), and 100-nm source electrode (Ag) and drain electrode (Ag).

[0040] See Figure 5 , the electrical test of the perovskite dielectric layer phototransistor shows a standard P-type transistor transfer characteristic curve at room temperature, and the device can also work at a very low voltage (<2V).

[0041] See Figure 6 and Figure 7 , the device demonstrates its photodetection performance under 265-nm light illumination. When the device is irradiated with a 265-nm light source at different power densities, it exhibits obvious light response characteristics, and its light response time is about 23 ms, demonstrating extremely sensitive deep ultraviolet light detection ability.

[0042] Example 3

[0043] Correspondingly, this example provides a method for preparing a perovskite dielectric layer phototransistor. Taking the bottom-gate top-electrode transistor as an example, PEA2PbBr4 and PDVT-10 are used as the dielectric layer and semiconductor layer respectively to prepare the phototransistor.

[0044] 1) Prepare the PEA2PbBr4 perovskite dielectric layer solution:

[0045] Dissolve PEABr / PbBr2 in DMF at a molar ratio of 2:1 to prepare a 0.1M concentration PEA2PbBr4 precursor solution, and then heat it on a hot plate at 70 °C for two hours. After it is fully dissolved, the PEA2PbBr4 perovskite dielectric layer solution can be obtained.

[0046] Other perovskite dielectric layer precursor solutions can be prepared similarly. For example, PEACl / SnCl2 or PEACl / PbCl2 are dissolved in DMF or DMSO at a molar ratio of 2:1 to prepare 0.1M concentration PEA2SnCl4 and PEA2PbCl4 precursor solutions, and then heated on a hot plate at 70 °C for two hours. After they are fully dissolved, the corresponding perovskite solutions can be obtained.

[0047] 2) Spin-coat the broadband gap organic-inorganic hybrid perovskite solution on the substrate with electrodes and anneal at low temperature

[0048] to form the dielectric layer:

[0049] Spin-coat the heavily doped silicon wafer (Si ++) The substrate (substrate with a gate electrode) is ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol in sequence for 1 minute, and after the cleaning is completed, it is dried with an argon gun. Then the substrate is transferred to an ozone treatment device and treated for 15 minutes to change the wettability of the substrate surface, which is beneficial for subsequent thin film deposition. The PEA2PbBr4 perovskite dielectric layer solution prepared in step 1 is spin-coated on the treated substrate at a rotation speed of 4000 rpm for 30 seconds, and the annealing process is heating at 100 °C for 5 minutes to form a dielectric layer.

[0050] 3) Deposit an organic semiconductor onto the dielectric layer to form a channel layer:

[0051] Dissolve PDVT-10 in a chlorobenzene solvent at a concentration of 5 g / L, heat and dissolve at 60 °C to form a PDVT-10 semiconductor solution. Then spin-coat the PDVT-10 semiconductor solution on a PDMS substrate. Without annealing the semiconductor layer, directly press the side with PDVT-10 onto the annealed perovskite thin film, and then lift the PDMS to transfer PDVT-10 onto the perovskite to form a channel layer.

[0052] 4) Fabricate a source electrode and a drain electrode on the channel layer:

[0053] Evaporate 100 nm of Ag as the source and drain electrodes on the channel layer through a mask to complete the preparation of the perovskite dielectric layer phototransistor.

[0054] The above uses specific examples to elaborate on the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. Those skilled in the technical field to which the present invention pertains can also make several simple deductions, deformations, or substitutions based on the concept of the present invention. These deduction, deformation, or substitution schemes also fall within the scope of the claims of the present invention.

Claims

1. A phototransistor with a perovskite dielectric layer, characterized in that, The transistor has a bottom-gate structure and includes a gate electrode, a dielectric layer, a channel layer, a source electrode, and a drain electrode; the dielectric layer is a wide-bandgap organic-inorganic hybrid perovskite; the channel layer is an organic semiconductor; and the channel layer is on the dielectric layer.

2. The optoelectronic transistor with a perovskite dielectric layer according to claim 1, characterized in that The wide-bandgap organic-inorganic hybrid perovskite is a quasi-two-dimensional perovskite with a bandgap greater than 3.0 eV.

3. The optoelectronic transistor with a perovskite dielectric layer according to claim 2, characterized in that The quasi-two-dimensional perovskite is A2MZ4 (A = (PEA) x (BA) y ; M = Pb x Sn y ; Z = Br x Cl y ; x + y = 1).

4. A perovskite dielectric layer phototransistor according to any one of claims 1-3, characterized in that, The thickness range of the perovskite dielectric layer is 80 nm to 200 nm.

5. A method for preparing a perovskite dielectric layer-based optoelectronic transistor, characterized in that, The transistor has a bottom-gate structure, and the manufacturing method includes the following steps: 1) Prepare a wide-bandgap organic-inorganic hybrid perovskite solution; 2) Spin-coat the wide-bandgap organic-inorganic hybrid perovskite solution on a substrate with electrodes and perform low-temperature annealing to form a dielectric layer; 3) Deposit an organic semiconductor onto the dielectric layer to form a channel layer.

6. The preparation method of a perovskite dielectric layer-based optoelectronic transistor according to claim 5, characterized in that, The electrodes are the gate electrode, the source electrode, and the drain electrode; or the electrode is the gate electrode, and the source electrode and the drain electrode are prepared on the channel layer.

7. The preparation method of a perovskite dielectric layer-based optoelectronic transistor according to any one of claims 5-6, characterized in that The wide-bandgap organic-inorganic hybrid perovskite is a quasi-two-dimensional perovskite with a bandgap greater than 3.0 eV.

8. The preparation method of a perovskite dielectric layer-based optoelectronic transistor according to claim 7, characterized in that, The quasi-two-dimensional perovskite is A2MZ4 (A = (PEA) x (BA) y ; M = Pb x Sn y ; Z = Br x Cl y ; x + y = 1).

9. The preparation method of a perovskite dielectric layer-based optoelectronic transistor according to any one of claims 5-8, characterized in that The deposition method of the channel layer is dry transfer.

10. The preparation method of a perovskite dielectric layer-based optoelectronic transistor according to any one of claims 5-9, characterized in that, The spin-coating speed of the perovskite precursor solution is 4000 - 6000 rpm, and the annealing temperature is 100°C - 150°C.

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