A heterojunction material with high solar energy conversion efficiency and its application

Abstract

The present invention relates to a heterojunction material with high solar energy conversion efficiency and its application, belonging to the technical field of semiconductor heterojunction. In the heterojunction material, a hexagonal wrinkled honeycomb-shaped BlueP two-dimensional semiconductor layer is stacked on a γ-GeS two-dimensional semiconductor layer with a similar structure, and there is a vacuum layer between the layers. Among them, there are three stacking modes between the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer. The formed heterojunction material is a hexagonal crystal system. Through strain regulation, oxidation reaction and reduction reaction can be achieved in the heterojunction on different semiconductor layers, which is beneficial to improving the solar energy conversion efficiency. The calculation results show that the solar energy conversion efficiency (STH) and functional conversion efficiency (PCE) of the γ-GeS / BlueP heterojunction material can reach 18.06% and 15.08% respectively, which has great commercial application potential.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor heterojunctions and relates to a heterojunction material with high solar energy conversion efficiency and application thereof. Background Art

[0002] In order to achieve the goal of carbon reduction in the energy field and accelerate the construction of a modern energy system, the development and utilization of clean energy has received widespread attention. As an important component of clean energy, the utilization efficiency of solar energy is directly related to the economic feasibility of energy conversion. In solar energy technology, photocatalytic hydrogen production and photovoltaic power generation are considered to be potential technical solutions to solve energy crises and environmental problems. Studies have shown that when the hydrogen production efficiency of solar photocatalysts exceeds 10%, it is economically competitive; and the power conversion efficiency of solar cells must exceed 18% to be considered cost-effective. The realization of these goals is inseparable from the support of wide spectral response, high carrier mobility and strong redox ability.

[0003] In recent years, with the discovery and research of graphene, the superior performance of two-dimensional materials has been widely recognized. Through mechanical exfoliation, thermal exfoliation or chemical methods, scientists have been able to prepare two-dimensional materials and deeply study their properties. Due to their unique optical and electrical properties, two-dimensional materials have shown important value in high-tech fields such as electronic materials and batteries. At the same time, their large surface area, multiple redox sites and excellent carrier mobility make them have significant application potential in the field of solar energy conversion.

[0004] Among the existing two-dimensional materials, Group IV compounds and phosphides are regarded as ideal materials for developing next-generation optoelectronic devices and high-performance photocatalysts due to their unique semiconductor behavior, visible light response and low cost. For example, γ-GeS has a camelback band structure, adjustable band gap and high mechanical anisotropy; blue phosphorene (BlueP) has a wide indirect band gap and adjustable electronic properties. Although two-dimensional materials have shown great potential in the fields of optoelectronics and photocatalysis, the existing technology still has the following problems: the performance of a single material is difficult to simultaneously meet the requirements of wide spectral response, high carrier mobility and strong redox ability; in practical applications, the solar energy conversion efficiency of existing materials has not yet reached the ideal level of industrial production. Summary of the invention

[0005] The primary purpose of the present invention is to provide a heterojunction material with high solar energy conversion efficiency; another purpose of the present invention is to provide the application of the heterojunction material with high solar energy conversion efficiency in photocatalytic water decomposition to hydrogen and solar cells.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solutions: a heterojunction material with high solar energy conversion efficiency, the heterojunction material comprising a BlueP two-dimensional semiconductor layer and a γ-GeS two-dimensional semiconductor layer, the BlueP two-dimensional semiconductor layer being stacked on the γ-GeS two-dimensional semiconductor layer, and a vacuum layer being between the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer; the conformations of the BlueP and γ-GeS two-dimensional semiconductor single layers are both hexagonal corrugated honeycomb; the heterojunction material is a hexagonal crystal system; the stacking method is any one of type 1 stacking, type 2 stacking or type 3 stacking.

[0007] Furthermore, the type 1 stacking method is to stack the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensure that the P atoms in the BlueP two-dimensional semiconductor layer and the S atoms in the γ-GeS two-dimensional semiconductor layer are aligned in the z direction.

[0008] Furthermore, the type 2 stacking method is to stack the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensure that the P atoms in the BlueP two-dimensional semiconductor layer and the Ge1 atoms in the γ-GeS two-dimensional semiconductor layer are aligned in the z direction.

[0009] Furthermore, the type 3 stacking method is to stack the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensure that the P atoms in the BlueP two-dimensional semiconductor layer and the Ge2 atoms in the γ-GeS two-dimensional semiconductor layer are aligned in the z direction.

[0010] Furthermore, the thickness of the vacuum layer is 30Å.

[0011] The present invention also provides application of the heterojunction material with high solar energy conversion efficiency in the field of solar energy conversion.

[0012] The beneficial effects of the present invention are as follows: the present invention provides a heterojunction material with high solar energy conversion efficiency, in which a BlueP two-dimensional semiconductor layer is stacked on a γ-GeS two-dimensional semiconductor layer, and a vacuum layer exists between the two two-dimensional semiconductor layers, wherein three different stacking methods are adopted between the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer, namely, stacking the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensuring that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 1 stacking method), stacking the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensuring that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 2 stacking method), stacking the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensuring that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 3 stacking method), stacking the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensuring that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 4 stacking method), stacking the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensuring that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 5 stacking method), stacking the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensuring that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 6 stacking method), stacking the BlueP two-dimensional semiconductor layer -GeS two-dimensional semiconductor layer Ge1 atoms are aligned in the z direction (type 2 stacking method) and BlueP two-dimensional semiconductor layer is stacked on γ-GeS two-dimensional semiconductor layer and ensures that P atoms in BlueP two-dimensional semiconductor layer and Ge2 atoms in γ-GeS two-dimensional semiconductor layer are aligned in the z direction (type 3 stacking method). The γ-GeS / BlueP heterojunction material formed by BlueP two-dimensional semiconductor layer and γ-GeS two-dimensional semiconductor layer is a hexagonal crystal system. Through strain regulation, oxidation reaction and reduction reaction can be realized in different semiconductor layers in this heterojunction. Its band edge potential is affected by the vacuum energy level of each semiconductor, and the oxidation potential and reduction potential are no longer directly related. Therefore, there is no need for each single-layer two-dimensional semiconductor to differ by 1.23 eV, the heterojunction material retains the good light absorption ability of each layer constituting the heterojunction structure in different directions, so that it has strong light absorption ability in the visible light to ultraviolet light region. It is found through calculation that the solar energy conversion efficiency and functional conversion efficiency of γ-GeS / BlueP can reach 18.06% and 15.08% respectively. Compared with MoSe2 / Ti2CO2 heterojunction materials, InTe / Bismuthene heterojunction materials and GeS / GeSe heterojunction materials, its solar energy conversion efficiency is outstanding and has great commercial application potential.

[0013] Other advantages, objectives and features of the present invention are described in the following description to some extent, and in some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the events of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of a high-efficiency solar energy conversion system of a γ-GeS / BlueP heterojunction material is provided for an embodiment of the present invention.

[0015] Figure 2The top view and side view are the molecular structures of the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer in Examples 1 to 3, wherein (a) is the top view and side view of the molecular structure of the BlueP two-dimensional semiconductor layer, (b) is the top view and side view of the molecular structure of the γ-GeS two-dimensional semiconductor layer, (c) and (d) are energy band structure diagrams of BlueP and γ-GeS, respectively, and the horizontal axis is point K.

[0016] Figure 3 The stacking structure diagrams of the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer in the heterojunction materials in Examples 1 to 3, where (a) PS is type 1 stacking mode, P-Ge1 is type 2 stacking mode, and P-Ge2 is type 3 stacking mode; (b) is the energy band structure diagram and electronic state density diagram corresponding to P-Ge1 under the HSE06 functional.

[0017] Figure 4 The band structure diagram and the distribution of CBM and VBM of the γ-GeS / BlueP heterojunction material in Example 2 after strain regulation under the HSE06 functional.

[0018] Figure 5 This is a diagram of the interface properties of Example 2 with and without strain.

[0019] Figure 6 This is a flowchart of the working process of the γ-GeS / BlueP heterojunction material participating in the photocatalytic decomposition of water to produce hydrogen in Example 2.

[0020] Figure 7 These are the optical absorption spectra of the BlueP two-dimensional semiconductor material, the γ-GeS two-dimensional semiconductor material, and the γ-GeS / BlueP heterojunction material with or without strain in Example 2 under the HSE06 functional. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied by other different specific examples, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and the features in the embodiments can be combined with each other without conflict.

[0022] Example 1

[0023] A heterojunction material with high solar energy conversion efficiency, in which a BlueP two-dimensional semiconductor layer is stacked on a γ-GeS two-dimensional semiconductor layer and the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 1 stacking mode), and there is a vacuum layer with a thickness of 30Å between the layers. Under sunlight, the heterojunction material absorbs photons, excites electrons to jump from the valence band to the conduction band and leaves holes in the valence band, thereby achieving solar energy conversion.

[0024] Example 2

[0025] A heterojunction material with high solar energy conversion efficiency, in which a BlueP two-dimensional semiconductor layer is stacked on a γ-GeS two-dimensional semiconductor layer and the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the Ge1 atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (Type 2 stacking mode), and there is a vacuum layer with a thickness of 30Å between the layers. Under sunlight, the heterojunction material absorbs photons, excites electrons to jump from the valence band to the conduction band and leaves holes in the valence band, thereby achieving solar energy conversion.

[0026] Example 3

[0027] See also Figure 1 ,from Figure 1 A heterojunction material with high solar energy conversion efficiency can be seen in the figure, in which the BlueP two-dimensional semiconductor layer is stacked on the γ-GeS two-dimensional semiconductor layer and the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the Ge2 atoms in the γ-GeS two-dimensional semiconductor layer in the z direction (type 3 stacking mode), and there is a vacuum layer with a thickness of 30Å between the layers. Under sunlight, the heterojunction material absorbs photons, excites electrons to jump from the valence band to the conduction band and leaves holes in the valence band, thereby realizing solar energy conversion.

[0028] See also Figure 2 ,from Figure 2 From (a) in the figure, it can be seen that the structure of the BlueP two-dimensional semiconductor monolayer is a hexagonal folded honeycomb; Figure 2 As can be seen in (b), the structure of the γ-GeS two-dimensional semiconductor monolayer is a hexagonal wrinkled honeycomb.

[0029] See also Figure 3 , where PS is type 1 stacking, P-Ge1 is type 2 stacking, and P-Ge2 is type 3 stacking. Figure 3 It can be seen that in all three stacking methods, the BlueP two-dimensional semiconductor layer is on the top and the γ-GeS two-dimensional semiconductor layer is on the bottom. The atoms in the two two-dimensional semiconductor layers are aligned differently, and there is a vacuum layer (blank space in the figure) and van der Waals force between the upper and lower layers.

[0030] Both BlueP and γ-GeS two-dimensional semiconductor materials belong to the hexagonal system, and the lattice parameters of the two materials are calculated and optimized respectively. Among them, the lattice constant of BlueP is 3.64Å, and the lattice constant of γ-GeS is 3.28Å. Through calculation, it is found that the lattice mismatch rate corresponding to the heterojunction material is within the range allowed by the heterojunction (δ <5%). Since there are different stacking methods between layers, by adding a 30Å vacuum space in the z direction of the supercell, the interlayer interaction caused by the periodic boundary conditions is avoided, and a new type of γ-GeS / BlueP heterojunction material is constructed. In order to obtain the most stable γ-GeS / BlueP heterojunction material, the relationship between "stacking type-layer spacing-interface binding energy" is established, and the stability of the heterojunction material structure formed by different stacking methods in Examples 1 to 3 is compared. The test results are shown in Table 1.

[0031] Table 1 compares the structural stability of the γ-GeS / BlueP heterojunction materials in Examples 1 to 3.

[0032] Table 1

[0033] Example Stacking method Interlayer distance (Å) <![CDATA[Interface binding energy (meV / Å 2 )]]> Example 1 Type 1 3.52 -8.50 Example 2 Type 2 3.51 -8.54 Example 3 Type 3 3.53 -8.49

[0034] As can be seen from Table 1, the γ-GeS / BlueP heterojunction material using type 2 stacking has the smallest binding energy. Therefore, its corresponding structure is the most stable. The distance between the two semiconductor layers of BlueP and γ-GeS was measured, and the interlayer spacing was 3.51Å.

[0035] The PBE functional and HSE06 functional were used to analyze the BlueP two-dimensional semiconductor materials (such as Figure 2 (c) in the figure), γ-GeS two-dimensional semiconductor materials (such as Figure 2 (d) in the figure) and the γ-GeS / BlueP heterojunction material under strain in Example 2 (as shown in Figure 3 (b) in the figure) for band analysis. Figure 3 As can be seen in (b), both VBM (valence band) and CBM (conduction band) are provided by the γ-GeS two-dimensional semiconductor layer, and the γ-GeS / BlueP heterojunction material has an indirect band gap of 1.05 eV. Therefore, this will lead to aggravated carrier recombination, which is not conducive to solar energy conversion. To this end, through strain regulation, such as Figure 4As shown in the figure, it can be seen that the CBM and VBM of the γ-GeS / BlueP heterojunction after strain regulation are provided by different layers and have a small indirect band gap. Therefore, the carrier recombination between the γ-GeS semiconductor layer and the BlueP semiconductor layer will be faster than the recombination within each layer. In addition, the γ-GeS / BlueP heterojunction material has a staggered band structure, which is conducive to the effective separation of photogenerated electrons and holes.

[0036] The interface properties of the γ-GeS / BlueP heterojunction material with and without strain in Example 2 were analyzed. By calculating the work function of the γ-GeS / BlueP heterojunction material and each component, it was found that within a small strain range, the work function of the BlueP two-dimensional semiconductor layer is always greater than that of the γ-GeS two-dimensional semiconductor layer. Since electrons flow from materials with low work functions to materials with high work functions in a heterojunction, when the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer come into contact, electrons flow from the γ-GeS two-dimensional semiconductor layer to the BlueP two-dimensional semiconductor, thereby forming a built-in electric field pointing from γ-GeS to BlueP near the interface. Under the action of this built-in electric field, the photocatalytic mechanism is effectively improved. For a more intuitive observation, three-dimensional and two-dimensional differential charge density analysis was performed on the γ-GeS / BlueP heterojunction material (where the electron density difference was set to 0.0003), and the analysis results are shown as follows. Figure 5 As shown. Figure 5 It can be seen that in the strained and unstrained γ-GeS / BlueP heterojunctions, the charge density is mostly redistributed near the interface. The two-dimensional and three-dimensional differential charge density methods are used to describe the charge distribution. The charge density difference is defined by the following equation:

[0037]

[0038] In the above equation, is the differential charge density, represents the charge density of the γ-GeS / BlueP heterojunction material, represents the charge density of the BlueP two-dimensional semiconductor layer, represents the charge density of the γ-GeS two-dimensional semiconductor layer. Figure 6 In the γ-GeS / BlueP heterojunction, electrons are mainly accumulated near the interface and depleted near the blue phosphorus layer. In addition, the competitive relationship between the electrostatic potential drop (ΔP) and the work function difference can well explain the charge transfer curves in the unstrained and strained γ-GeS / BlueP heterojunctions. Figure 5As shown in Figure 2, in the γ-GeS / BlueP heterojunction, the electrostatic potential depth of the BlueP layer is always lower than that of the γ-GeS layer, resulting in electron migration from BlueP to γ-GeS. In addition, the large ∆P under various strains forms a strong electrostatic field at the interface, which helps prevent the recombination of photogenerated electrons and holes, which effectively improves the solar energy conversion efficiency.

[0039] The γ-GeS / BlueP heterojunction material in Example 2 can be used as a photocatalyst and solar cell for solar energy conversion through strain engineering. The working mechanism is shown in the figure below. Figure 6 As shown. Figure 6 It can be seen that when used as a photocatalyst material, under sunlight, the photogenerated electrons in the γ-GeS / BlueP heterojunction material change their flow direction under the action of the built-in electric field. The photogenerated electrons jump from the valence band of the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer to the conduction band, respectively, leaving their own photogenerated holes in the valence band. The photogenerated electrons in the BlueP two-dimensional semiconductor layer move to the left under the influence of the built-in electric field, and recombine with the holes in the valence band of the γ-GeS two-dimensional semiconductor layer as photogenerated carriers, leaving holes in the valence band of the BlueP two-dimensional semiconductor layer and electrons in the conduction band of the γ-GeS two-dimensional semiconductor layer, so that a large number of electrons and holes can be accumulated for redox reactions. According to the energy band formula of photocatalytic water junction, the two-dimensional semiconductor layer must satisfy:

[0040]

[0041]

[0042] In the above equation, and Represent the reduction potential and oxidation potential of H2O at different pH values. In the γ-GeS / BlueP heterojunction material, the redox reaction occurs on different semiconductor layers, and its band edge potential is affected by the vacuum energy level of each layer. The oxidation potential and reduction potential are no longer directly related, so there is no need for a 1.23 eV difference for each single layer. Since light absorption occurs on two two-dimensional semiconductor layers, it is no longer restricted by the band gap of a single two-dimensional semiconductor layer. Each two-dimensional semiconductor layer only needs the top of the valence band or the bottom of the conduction band to meet the oxidation or reduction potential requirements, and there is no requirement for its band gap. Therefore, a two-dimensional semiconductor layer with a relatively small band gap can be selected to form a heterojunction, increase light absorption to increase the solar energy conversion rate (i.e., increase the redox ability), and reduce the carrier recombination rate while retaining light absorption to the greatest extent.

[0043] The electrons in the γ-GeS / BlueP heterojunction material absorb energy and are stimulated to transition from the valence band to the conduction band, leaving the photogenerated holes in the valence band. Among them, the photogenerated electrons have the ability to reduce. After transitioning to the surface of the γ-GeS / BlueP heterojunction material, they can reduce the H in water. + A reduction reaction occurs, making H + The photogenerated holes in the valence band have oxidation ability, oxidizing water into oxygen (the specific reaction process is shown in the following reaction formula). The whole process realizes the conversion of solar energy into chemical energy.

[0044] * +H + + e - → *H

[0045] *H + H + + e - → * + H2(g)

[0046] * + H2O → OH + H + + e -

[0047] *OH → *O + H + + e -

[0048] *O + H2O → *OOH + H + + e -

[0049] *OOH → * + O2(g) + H + + e -

[0050] In addition, strong light absorption performance in the entire visible light region is also an important condition for efficient solar energy conversion materials. Therefore, the light absorption analysis of the γ-GeS / BlueP heterojunction material in Example 2 was carried out. Figure 7 shown.

[0051]

[0052] In the above equation, It represents the efficiency of solar hydrogen production, where a coefficient of 0.5 means that only half of the photogenerated carriers can participate in the subsequent catalytic process. is the photon energy AM1.5G solar flux under , the integral from 0 to ∞ represents the total power density of the incident sunlight. ΔG represents the potential difference for water decomposition. E′ is equivalent to the band gap of a large band gap light absorber.

[0053] The calculation results are shown in Table 2. It can be seen from Table 2 that the STH of the γ-GeS / BlueP heterojunction material can reach a maximum of 18.06%, and the PCE can reach a maximum of 15.08%, both of which meet market demand. This shows that the γ-GeS / BlueP heterojunction material in the present invention has excellent solar energy conversion performance and has great commercial application potential.

[0054] Table 2

[0055] stress <![CDATA[η STH ]]> <![CDATA[η PCE ]]> -3% 12.21% 15.08% -4% 18.06% 5.15% 9% 13.20% 12.25% 10% 13.77% 11.03%

[0056] In summary, the present invention provides a heterojunction material with high solar energy conversion efficiency. In the heterojunction material, a hexagonal corrugated honeycomb-shaped BlueP two-dimensional semiconductor layer is stacked on a γ-GeS two-dimensional semiconductor layer with a similar structure, and there is a vacuum layer and van der Waals force between the layers. There are three stacking modes between the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer, and the formed heterojunction material belongs to the hexagonal crystal system. Through strain regulation, oxidation reaction and reduction reaction can be realized in the heterojunction material on different semiconductor layers, and its band edge potential is affected by the vacuum energy level of each semiconductor, and the oxidation potential and reduction potential are no longer directly related. Therefore, there is no need for a difference of 1.23eV for each single-layer two-dimensional semiconductor. Calculations show that the efficiency of solar energy conversion to hydrogen (STH) and functional conversion efficiency (PCE) of the γ-GeS / BlueP heterojunction material reach 18.06% and 15.08%, respectively, and can be widely used in the field of solar energy conversion.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A heterojunction material with high solar energy conversion efficiency, characterized in that: The heterojunction material includes a BlueP two-dimensional semiconductor layer and a γ-GeS two-dimensional semiconductor layer, the BlueP two-dimensional semiconductor layer is stacked on the γ-GeS two-dimensional semiconductor layer, and there is a vacuum layer between the BlueP two-dimensional semiconductor layer and the γ-GeS two-dimensional semiconductor layer; the conformations of the BlueP and γ-GeS two-dimensional semiconductor single layers are both hexagonal corrugated honeycomb; the heterojunction material is a hexagonal crystal system; the stacking method is any one of type 1 stacking, type 2 stacking or type 3 stacking.

2. The heterojunction material with high solar energy conversion efficiency according to claim 1, characterized in that: The type 1 stacking method is to stack the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensure that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the S atoms in the γ-GeS two-dimensional semiconductor layer in the z direction.

3. The heterojunction material with high solar energy conversion efficiency according to claim 1, characterized in that: The type 2 stacking method is to stack the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensure that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the Ge1 atoms in the γ-GeS two-dimensional semiconductor layer in the z direction.

4. The heterojunction material with high solar energy conversion efficiency according to claim 1, characterized in that: The type 3 stacking method is to stack the BlueP two-dimensional semiconductor layer on the γ-GeS two-dimensional semiconductor layer and ensure that the P atoms in the BlueP two-dimensional semiconductor layer are aligned with the Ge2 atoms in the γ-GeS two-dimensional semiconductor layer in the z direction.

5. The heterojunction material with high solar energy conversion efficiency according to claim 1, characterized in that: The vacuum layer thickness is 30Å.

6. Use of the heterojunction material with high solar energy conversion efficiency according to any one of claims 1 to 5 in solar energy conversion.

Images