Temperature-related Foster energy transfer efficiency regulation and control method

Abstract

The invention discloses a temperature-related # imgabs 0 # energy transfer efficiency regulation method, which comprises the following steps of: preparing a two-dimensional organic-inorganic heterojunction structure, putting a heterojunction sample into a cold table, putting the cold table under a fluorescence spectrophotometer, and connecting temperature control equipment, so that the temperature of the sample can be controlled to regulate the # imgabs 1 # energy transfer efficiency of the sample. A new angle is provided for FRET adjustment of the two-dimensional material, the insight of interlayer charge and energy transfer is improved, the research has important significance for detecting interaction of nanoscale, and the method has wide application prospects in the fields of biomedicine, sensing, imaging and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a two-dimensional organic-inorganic heterojunction capable of generating high Förster energy transfer efficiency and a method for regulating the Förster energy transfer efficiency. Background Art

[0002] Förster resonance energy transfer (FRET) is a non-radiative energy transfer process from a donor to an acceptor through intermolecular dipole-dipole coupling. This is a phenomenon usually observed in a short range of 1 to 10 nm between the donor and the acceptor. It can convert the interaction between different materials into changes in fluorescence signals with high sensitivity and can be used to study the generation, recombination and migration of carriers. Therefore, FRET is a powerful tool for detecting nanoscale interactions and has been widely used in biomedicine, sensing and imaging.

[0003] On the other hand, two-dimensional materials have nanometer-level thickness, which effectively suppresses the short channel effect of semiconductor devices, reduces device size, and reduces power consumption. With the advancement and development of science and technology, the importance of two-dimensional materials in many fields has gradually become prominent and has received widespread attention. In recent years, graphene, graphene oxide, molybdenum disulfide, graphene quantum dots, etc. have been widely used as donor or acceptor materials in FRET detection due to their unique optical properties (such as high quantum yield, narrow emission spectrum, and photostability). FRET also plays an important role in studying the carrier dynamics and optoelectronic properties of two-dimensional materials. Therefore, two-dimensional materials are an excellent research platform for FRET.

[0004] At present, FRET technology is mainly related to the research on the optical properties of quantum dots, the interaction between nanomaterials and biomolecules, and the development of biosensors. However, most FRET devices based on quantum dots usually have disadvantages such as uneven size, poor fluorescence reproducibility and dispersion. The atomic thickness of two-dimensional materials makes them suitable for flexible and transparent electronic / optoelectronic devices, and they have high surface areas, which is conducive to the realization of multi-channel detection platforms. The regulation of Förster energy transfer efficiency in two-dimensional materials is believed to be able to effectively promote their applications in sensing, imaging and biomedicine. Summary of the invention

[0005] The purpose of the present invention is to provide a method for effectively adjusting the Förster energy transfer efficiency in a two-dimensional organic-inorganic heterojunction. The method is simple to operate, the prepared heterojunction is uniform and stable, and the adjustment sensitivity of the Förster energy transfer efficiency is high.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: prepare a two-dimensional organic-inorganic heterojunction, and connect the sample to a temperature control device for PL testing. It includes the following steps: 1) Prepare a single layer of WS2 and a thin layer of hexagonal boron nitride (hBN) by mechanical exfoliation. Use the thin layer of hBN as a substrate and use its high matching degree with the organic single crystal lattice for PVD growth to obtain high-quality, orderly stacked organic single crystal pentacene. 2) Stacking a single layer of WS2 onto organic single crystal pentacene to construct a type-II heterojunction, in which the Förster energy transfer is based on WS2 as the acceptor and organic single crystal pentacene as the donor; 3) placing the heterojunction sample in a cold stage and then placing it under a fluorescence spectrometer, wherein the cold stage is respectively connected to a temperature controller and a liquid nitrogen tank; 4) Adjust the sample environment to multiple different temperatures through the temperature controller and test the PL spectra of the samples at different temperatures; 5) Characterize the variation of Förster energy transfer efficiency of the sample with temperature by analyzing the changes in PL spectrum.

[0007] Preferably, the thickness of the single layer WS2 in step 1) is 0.6 nm, and the thickness of the thin layer hBN is 0.33-3 nm.

[0008] Preferably, the type-II heterojunction in step 2) is formed by vertically stacking using a dry transfer method.

[0009] Preferably, the temperature in step 4) ranges from 83K to room temperature.

[0010] Preferably, the organic single crystal pentacene is a wetting layer pentacene, and its PL spectrum decreases with decreasing temperature, that is, the fluorescence quantum yield decreases.

[0011] The present invention provides a method for adjusting the Förster energy transfer efficiency in the preparation of a Förster energy transfer device. Combining two essentially different materials (such as an inorganic TMD material and an organic single crystal material) is an effective way to study Förster energy transfer. Temperature changes can bring about changes in the PL spectra of the donor and the acceptor, affecting the overlap of the PL spectra of the two, thereby causing changes in the Förster energy transfer efficiency.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The test cost of the present invention is low, the operation is simple, the success rate is high, and it fully meets the laboratory test requirements. The success rate reaches 90%, and a large amount of experimental costs are saved.

[0013] 2. The sample size is small and the properties are stable, which is conducive to integration.

[0014] 3. The present invention finds that the Förster energy transfer efficiency of the sample is highly sensitive to changes in temperature, which is beneficial for applications in temperature detection, temperature sensing, temperature imaging, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a specific structural diagram of the heterojunction sample in the present invention; Figure 2 It is a schematic diagram of the device connection of the present invention; Figure 3 The temperature-dependent PL spectral characteristics of the two-dimensional organic-inorganic heterojunction prepared in Example 1; Figure 4 The PL of the heterojunction pentacene part prepared in Example 1 is compared with the absorption spectrum of the single-layer WS2. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] In the following examples, unless otherwise specified, the operating methods are generally carried out under conventional conditions or conditions recommended by the manufacturer, and the raw materials and reagents used are all commercially available products.

[0018] Example 1 The present invention designs a research method for adjusting the Förster energy transfer efficiency in a heterojunction on a two-dimensional scale. The specific process includes the following steps: 1) A single layer of WS2 and a thin layer of hBN were prepared by mechanical exfoliation. The thin layer of hBN was used as a substrate and PVD growth was performed using its high matching degree with the organic single crystal lattice to obtain high-quality, orderly stacked organic single crystal pentacene. WS2 has a direct band gap that leads to strong luminescence, a strong quantum confinement effect and stable excitons, and its single layer thickness is 0.6 nm. The thickness of the thin layer of hBN is 0.33~3 nm. 2) A single layer of WS2 is stacked onto a high-quality, orderly stacked organic single crystal pentacene using a dry transfer method to construct a type-II heterojunction. This heterojunction has adjacent double quantum wells of electrons and holes on both sides of the interface. The simultaneous confinement of electrons and holes in the wells results in the heterojunction having unique optical and electrical properties. Figure 1 As shown, from bottom to top, there are silicon wafers, thin layers of hBN, high-quality orderly stacked organic single crystal pentacene, and single layer WS2; the single crystal pentacene material has long-range order and high carrier mobility; 3) Place the heterojunction sample in a cold stage and place it under the fluorescence spectrometer. The cold stage is connected to a temperature controller and a liquid nitrogen tank, such as Figure 2 As shown; 4) Adjust the sample to multiple different ambient temperatures through the temperature controller. After the temperature stabilizes, test the PL spectra of the sample at different temperatures, such as Figure 3 As shown; 5) By comparing the fluorescence spectrum with the absorption spectrum of monolayer WS2, the Förster energy transfer efficiency of the sample is characterized as a function of temperature, such as Figure 4 As shown, this confirms that the method can adjust the Förster energy transfer efficiency by temperature.

[0019] This embodiment tests a total of 9 different temperatures (83K, 103K, 123K, 153K, 183K, 213K, 243K, 273K, 298K). Figure 3 As shown, the measured PL data proves that as the temperature decreases, the PL of single crystal pentacene in the heterojunction will decrease, causing a significant reduction in the overlap range with the WS2 absorption curve, resulting in a decrease in the amount of photon energy absorbed by pentacene supplied to WS2, and a significant decrease in the Förster energy transfer efficiency from organic single crystal pentacene to WS2 in the heterojunction.

Claims

1. A temperature-related regulation Energy transfer efficiency method, characterized in that The following steps are involved: 1) Prepare a single layer of WS2 and a thin layer of hBN by mechanical exfoliation, use the thin layer of hBN as a substrate, and use its high matching degree with the organic single crystal lattice for PVD growth to obtain high-quality, orderly stacked organic single crystal pentacene; 2) Stacking a single layer of WS2 onto an organic single crystal pentacene to construct a type-II heterojunction. The energy transfer is carried out with WS2 as the acceptor and organic single crystal pentacene as the donor; 3) placing the heterojunction sample in a cold stage and then placing it under a fluorescence spectrometer, wherein the cold stage is respectively connected to a temperature controller and a liquid nitrogen tank; 4) Adjust the sample environment to multiple different temperatures through a temperature controller and test the PL spectra of the samples at different temperatures; 5) Characterize the sample by analyzing the changes in PL spectra Variation of energy transfer efficiency with temperature.

2. A temperature-dependent method according to claim 1 A method for studying energy transfer efficiency, characterized in that: The thickness of the single layer WS2 in step 1) is 0.6 nm, and the thickness of the thin layer hBN is between 0.33 and 3 nm.

3. A temperature-dependent method according to claim 1 A method for studying energy transfer efficiency, characterized in that: The type-II heterojunction described in step 2) is vertically stacked using a dry transfer method.

4. A temperature-dependent method according to claim 1 A method for studying energy transfer efficiency, characterized in that: The temperature in step 4) ranges from 83K to room temperature.

5. The method for studying the temperature-dependent Forster energy transfer efficiency according to claim 1, characterized in that: The organic single crystal pentacene is a wetting layer pentacene, and its PL spectrum decreases with decreasing temperature, that is, the fluorescence quantum yield decreases.

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