Photoelectric property optimization method based on perovskite quantum dot modified enhanced two-dimensional material heterostructure

Abstract

The invention discloses a photoelectric property optimization method based on perovskite quantum dot modification and enhancement of a two-dimensional material heterostructure, and the method comprises the steps: carrying out the modification of a two-dimensional material n-type WS2 / MoS2 through perovskite quantum dots CsPbBr3QDs, generating an n-type doping effect, obtaining a CsPbBr3 / WS2 / MoS2 type II heterostructure with enhanced light current, and maintaining the inherent rapid response characteristic of the heterostructures. Compared with the original WS2 / MoS2, the CsPbBr3 / WS2 / MoS2 shows enhanced light current, light responsiveness and detection rate. The perovskite quantum dots can be used for improving the photoelectric property of the two-dimensional material heterostructure. The invention lays a foundation for advanced photovoltaic and high-sensitivity photoelectric detection technologies.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technology, and in particular to a method for optimizing the optoelectronic performance of a two-dimensional material heterostructure based on perovskite quantum dot modification. Background Art

[0002] In today's era of rapid technological advancement, the demand for high-performance photosensors continues to grow. Field-effect transistors (FETs) utilizing two-dimensional (2D) materials are a key solution due to their unique properties. However, challenges such as prolonged photoresponse time in single-material systems and limited photocurrent in heterostructure designs have hindered their performance improvements.

[0003] Two-dimensional (2D) materials have shown considerable advantages in nanoelectronic and photonic devices due to their sensitive optoelectronic response, excellent optical transparency, tunable band gap, and high carrier mobility. Perovskite quantum dots, which are characterized by their small size and high surface-to-volume ratio, exhibit unique optical and electrical properties, making them ideal for improving the performance of various optoelectronic devices.

[0004] Stacking various 2D materials to construct van der Waals heterostructures has significant advantages, especially in enhancing charge separation and transport processes and exhibiting improved photoelectric responses. Notably, type-II heterostructures are often used in photovoltaics, photodetectors, and light-emitting diodes due to their efficiency in generating and manipulating photogenerated carriers. However, the problem of insufficient photocarrier absorption and reduced optical gain in devices due to interfacial recombination between the two dimensions has greatly hindered the widespread deployment of heterojunction devices relying on 2D materials. Therefore, the photocurrent confinement of type-II heterostructures needs to be improved to meet the high standards of modern optoelectronics. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and to propose a method for optimizing the photoelectric performance of a two-dimensional material heterostructure based on perovskite quantum dot modification.

[0006] The purpose of the present invention is to achieve the following technical solutions: a method for optimizing the photoelectric performance of a two-dimensional material heterostructure based on perovskite quantum dots, by modifying perovskite quantum dots CsPbBr 3 The two-dimensional material is modified to produce an n-type doping effect, resulting in a II heterostructure with enhanced photocurrent.

[0007] Furthermore, the two-dimensional material heterostructure is a nn-type WS 2 / MoS 2 .

[0008] Furthermore, the type II heterostructure with enhanced photocurrent is CsPbBr 3 / WS 2 / MoS 2 .

[0009] Furthermore, the type II heterostructure CsPbBr 3 / WS 2 / MoS 2 While maintaining the fast response characteristics of the heterostructure, the photocurrent, photoresponsivity and detectivity can be enhanced.

[0010] Furthermore, mechanical exfoliation of n-type WS 2 / MoS 2 Transfer to Si / SiO 2 On the substrate, perovskite quantum dots CsPbBr 3 Spin coating onto the transferred heterojunction for quantum dot decoration.

[0011] Furthermore, the type II heterostructure CsPbBr 3 / WS 2 / MoS 2 The electrons on the two-dimensional material diffuse from the quantum dots to align the Fermi level and establish a new equilibrium. This energy level difference makes electron transfer easier and the potential barriers for electrons and holes change more.

[0012] Furthermore, based on the type II heterostructure CsPbBr 3 / WS 2 / MoS 2 Electron beam lithography and electron beam evaporation techniques were used to depict electrodes and deposit a layer of Cr (10 nm) and Au (30 nm) on the sample to prepare field effect transistor (FET) devices, thereby reducing the Schottky barrier and improving the conductivity of the FET devices.

[0013] Furthermore, the perovskite quantum dot surface acts as a photosensitizer, effectively capturing photons and promoting the generation and transport of charge carriers, thereby enhancing the photoelectric conversion of the heterostructure.

[0014] Beneficial effects of the present invention: The present invention studies the perovskite quantum dots CsPbBr 3 The photoelectric response enhancement characteristics of the modified 2D material make up for the shortcomings of poor photoelectric response and long recovery time of single-material FET. Subsequently, WS based on nn junction was prepared 2 / MoS 2 Type II heterostructure, and CsPbBr modified on the surface of the heterostructure 3 The results showed that CsPbBr 3 The incorporation of quantum dots is expected to enhance the generation of photocurrent while maintaining the fast response characteristics inherent in these heterostructures. 2 / MoS2 Compared with CsPbBr 3 / WS 2 / MoS 2 The enhanced photocurrent (I ph ), photoresponsivity (R) and detectivity (D*). Perovskite quantum dots can be used to improve the optoelectronic properties of two-dimensional material heterostructures. This invention lays the foundation for advanced photovoltaic and high-sensitivity photodetection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 CsPbBr 3 Microstructure of perovskite quantum dots and their effects on two-dimensional material MoS 2 , WS 2 Schematic diagram of the influence of energy band structure and surface potential;

[0017] Figure 2 CsPbBr 3 Perovskite quantum dots for MoS 2 , WS 2 Schematic diagram of the enhancement of the electrical characteristics of a field effect transistor;

[0018] Figure 3 CsPbBr 3 Perovskite quantum dots for WS 2 / MoS 2 Schematic diagram of the enhancement of the optoelectronic characteristics of a field effect transistor; DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific implementation examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] The present invention uses mechanical exfoliation to separate multilayer n-type MoS 2 , WS 2 Transfer to Si / SiO 2 After this process, CsPbBr 3 Quantum dots were spin-coated onto the above materials. The structural features before and after quantum dot modification were characterized to evaluate the effect of doping on the two-dimensional materials. Figure 1As shown in the figure, after QDs modification, the Raman peaks of all 2D materials shifted to lower wavenumbers. These results indicate that QDs modification leads to a significant n-type doping effect in 2D materials. In addition, the Raman intensity of the two-dimensional material decreased significantly with the coverage of quantum dots on the spin-coated samples. In addition, Kelvin probe force microscopy (KPFM) was used to measure the surface potential changes and confirm the doping effect after quantum dot modification. Compared with single 2D material samples, CsPbBr 3 The surface potential of 2D materials is relatively low compared to MoS 2 , WS 2 The KPFM images show that the CsPbBr 3 and pristine MoS 2 Compared with CsPbBr 3 / MoS 2 The region exhibits the highest surface potential and the brightest morphology, and electrons diffuse from the quantum dots into the 2D material to align the Fermi level and establish a new equilibrium. 2D materials and CsPbBr 3 The band gap diagram shows that the conduction band position of quantum dots (QDs) is higher than that of 2D materials. This energy level difference makes electron transfer easier because the potential barriers of electrons and holes vary greatly. Therefore, this facilitates the transfer of electrons from QDs to 2D materials, inducing an n-type doping effect.

[0021] CsPbBr 3 The structure and charge transfer behavior of the quantum dots were characterized to explore their interaction with 2D materials, with single CsPbBr 3 Compared with quantum dots. Single CsPbBr 3 The PL intensity of QDs is higher than that of CsPbBr 3 / MoS 2 and CsPbBr 3 / WS 2 The PL intensity of CsPbBr is about 3.41 and 2.35 times higher, indicating that charge transfer occurs at the interface under illumination. 3 , CsPbBr 3 / MoS 2 and CsPbBr 3 / WS 2 The peak positions of CsPbBr are approximately 515nm, 513nm, and 514nm. After integration with 2D materials, 3 The slight blue shift of the photoluminescence (PL) peak confirmed that electron transfer occurred under light illumination.

[0022] After verifying the doping and charge transfer properties of QDs on 2D materials, we fabricated them into FET devices and compared the performance of 2D materials and CsPbBr 3The electrical and optoelectronic behaviors of the 2D composite device. Figure 2 and Figure 3 As shown. CsPbBr 3 QDs were spin-coated onto 2D materials. The QD-coated samples were then fabricated into field-effect transistor (FET) devices. The QDs-coated samples were illuminated with 600 nm light (2 μm diameter, 2.5 mW cm -2 The FET device is composed of 2D materials and Au electrodes. By ds Fixed at 1V and V gs The transfer characteristics were measured by sweeping from -60V to +60V. MoS 2 and WS 2 Both before and after quantum dot modification, the original MoS exhibits typical n-type transport behavior. 2 The on / off ratio of the base device is about 10 7 , after QDs decoration, it dropped to about 10 5 The threshold voltage (V th ) shifts negatively, and also produces an n-type doping effect on 2D materials. 2 FETs show similar performance to MoS 2 Similar electrical and optoelectronic characteristics with reduced on / off ratio and V th Compared with the original 2D material, CsPbBr 3 The output curve of the 2D composite is more linear, with higher I ds QDs decoration also reduces the Schottky barrier and improves the conductivity of FET devices based on 2D materials. In order to study the optoelectronic properties of QDs decoration, the V ds =1V and V gs = 60V. The results confirm that QDs decoration enhances the photocurrent of the device and can be enhanced by V gs Further improvement. Under 8 seconds illumination, at 0V Vgs and 1V V ds Evaluation of 2D materials and CsPbBr 3 Dynamic optical response of CsPbBr / 2D composite devices. 3 The transferred electrons and dark current are about one order of magnitude higher than those of single 2D materials. Quantum dot decoration enhances the photocurrent and photoresponsivity.

[0023] The built-in electric field at the interface of heterojunction materials can accelerate and promote the transport and separation of photogenerated electron-hole pairs, thereby improving the performance of photonic devices. 2 / MoS 2The heterostructure is a typical type II nn heterostructure, indicating its potential for optoelectronic applications. Here, a single-hole molybdenum plate (10 μm diameter, 1 cm × 1 cm) was used as a shadow mask to selectively deposit QDs onto the WS of the heterostructure. 2 Top. Under illumination, electrons initially transfer from QDs to WS 2 , and then transferred to MoS 2 . Fixed V ds =1V, V gs The CsPbBr obtained by sweeping from -50V to +40V 3 / WS 2 / MoS 2 Transfer characteristic curve of the original WS 2 / MoS 2 The on / off ratio is about 10 5 , after QDs modification, it was reduced to 10 3 , V th Compared with the original state, WS 2 The QDs binding on MoS increases the surface work function difference 2 , resulting in an increase in the Schottky barrier and threshold voltage and a decrease in the on / off ratio. However, in comparison, CsPbBr 3 / WS 2 / MoS 2 Shows better than WS 2 / MoS 2 More prominent photoelectric response, CsPbBr 3 / WS 2 / MoS 2 The photoelectric current under illumination shows that it is similar to WS 2 / MoS 2 Compared with the conventional devices, the QDs have superior photoelectric performance. The QDs surface acts as a photosensitizer, effectively capturing photons and promoting the generation and transport of charge carriers, thereby enhancing the photoelectric conversion of the heterostructure. At the same time, the nn heterojunction characteristics of the device remain unchanged, resulting in a fast photoelectric response.

[0024] In order to evaluate the optoelectronic properties of quantum dot decorated heterostructures, illumination with different wavelengths and power densities was used to study the CsPbBr 3 / WS 2 / MoS 2 Dynamic optical response of heterostructures, CsPbBr 3 / WS 2 / MoS 2The heterostructure exhibits different photoelectric responses at different wavelengths, with the photoelectric response reaching peaks at 550nm and 600nm. However, beyond 600nm, the photoelectric response gradually weakens. This indicates that the device exhibits excellent sensing performance for visible light. In the wavelength range of 450nm to 700nm, the photoelectric response of the device is enhanced with the increase of light power, and increasing the power density of illumination enhances the photoelectric response of the heterostructure.

[0025] In the present invention, CsPbBr 3 Perovskite quantum dots modified on MoS 2 , WS 2 The surface will produce n-type doping effect. This integration realizes the 3 The highly efficient electron transfer from CsPbBr to 2D materials significantly enhances the optoelectronic performance of FETs based on individual 2D layers. This enhancement is evidenced by the increase in photocurrent and the reduction in response and recovery time. 3 QDs site-specific modification on WS 2 / MoS 2 Heterostructure surface. The results show that quantum dot-modified type-II heterostructures not only retain their inherent fast photoelectric response characteristics, but also exhibit a significant increase in photocurrent. The results demonstrate that integrating perovskite quantum dots with type-II heterostructures can effectively enhance the optoelectronic performance of these devices, thereby expanding their feasible applications in the field of photodetection.

[0026] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for optimizing the photoelectric performance of a two-dimensional material heterostructure based on perovskite quantum dot modification, characterized in that: The two-dimensional material is modified by perovskite quantum dots CsPbBr3 to produce an n-type doping effect, resulting in a type II heterostructure with enhanced photocurrent.

2. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure modified with perovskite quantum dots according to claim 1, characterized in that: The two-dimensional materials are n-type WS2 and MoS2.

3. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure modified with perovskite quantum dots according to claim 1, characterized in that: The type II heterostructure with enhanced photocurrent is CsPbBr3 / WS2 / MoS2.

4. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure modified with perovskite quantum dots according to claim 3, characterized in that: The type-II heterostructure CsPbBr3 / WS2 / MoS2 can enhance the photocurrent, photoresponsivity and detectivity while maintaining the fast response characteristics of the heterostructure.

5. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure modified with perovskite quantum dots according to claim 2, characterized in that: Mechanical exfoliation was used to transfer nn-type WS2 / MoS2 onto Si / SiO2 substrates, and perovskite quantum dots CsPbBr3 were spin-coated onto the transferred materials for quantum dot modification.

6. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure modified with perovskite quantum dots according to claim 3, characterized in that: Electrons on the type-II heterostructure CsPbBr3 / WS2 / MoS2 diffuse from quantum dots to the two-dimensional material to align the Fermi level and establish a new equilibrium. This energy level difference makes electron transfer easier and the potential barriers for electrons and holes change more.

7. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure modified with perovskite quantum dots according to claim 3, characterized in that: Field effect transistor FET devices were prepared based on type II heterostructure CsPbBr3 / WS2 / MoS2 to reduce the Schottky barrier and improve the conductivity of the FET devices.

8. The method for optimizing the photoelectric performance of a two-dimensional material heterostructure based on perovskite quantum dot modification according to claim 1, characterized in that: The perovskite quantum dots surface acts as a photosensitizer, effectively capturing photons and promoting the generation and transport of charge carriers, thereby enhancing the photoelectric conversion of the heterostructure.

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