A solid-phase doped perovskite photodiode

Abstract

The present invention discloses a solid-phase doped perovskite photodiode, comprising a perovskite photon absorber, a first doped metal layer, a second doped metal layer, a first electrode layer, and a second electrode layer; the first doped metal layer and the second doped metal layer are deposited on either side of the perovskite photon absorber, respectively, the first doped metal layer being used to obtain n-type doping, and the second doped metal layer being used to obtain p-type doping; metal ions in the first doped metal layer and the second doped metal layer penetrate into the perovskite photon absorber, forming a perovskite n-type layer and a perovskite p-type layer; the first electrode layer and the second electrode layer are deposited on either side of the first doped metal layer and the second doped metal layer, respectively, thereby forming a perovskite homojunction photodiode. The perovskite homojunction proposed in the present invention has a lattice-matched junction interface and few interface defects, thereby improving the detection quantum efficiency of the photodiode and reducing shot noise caused by defects.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection, and in particular to detection technology in the infrared / visible light / ultraviolet spectral regions. Background Art

[0002] Photodetection is a crucial component of information processing, utilizing the photoelectric effect to convert incident light into electrical signals. Perovskite materials possess exceptional photoelectric conversion and carrier transport capabilities, making them crucial for applications in photovoltaic and photodetection devices. While photoconductive sensors offer high responsivity, they suffer from high dark current and noise. Therefore, photodiodes are typically constructed using pn junctions or pin structures to improve the specific detectivity of photodetection.

[0003] In the fabrication of inorganic semiconductor photodiodes, methods such as ion implantation or high-temperature vapor diffusion are commonly used to create pn or pin junctions. However, due to the limited temperature tolerance of perovskites, ion implantation and high-temperature vapor diffusion can easily damage the perovskite crystal. To address these issues, methods such as spin coating or vapor deposition are used to deposit organic or inorganic layers on both ends of the perovskite crystal as carrier-blocking layers, creating perovskite heterojunctions (pn or pin). The interface lattice mismatch at the junction region of such perovskite heterojunctions results in numerous defects. These defects can cause recombination of photogenerated carriers at the interface, thereby reducing the quantum efficiency of photodetection. Furthermore, these interface defects can act as traps, capturing some photogenerated carriers. These photogenerated carriers can then be re-emitted, generating additional noise and reducing the photodiode's specific detectivity.

[0004] Some research groups have also proposed using solution epitaxy and solution doping to prepare perovskite homo- or heterojunctions. Perovskite junctions prepared by solution epitaxy and doping can achieve lattice-matched interfaces, but the thickness of the junction layer grown by solution epitaxy is often over several microns, and precise control is difficult. For light detection in the infrared, visible, and ultraviolet regions, the absorption depth of photons is typically hundreds of nanometers. If the depletion layer of the perovskite pn or pin junction is too thick, the drift length of the photogenerated carriers will be smaller than the junction thickness, and a large number of photogenerated carriers will recombine in the junction region, reducing the detection quantum efficiency. Summary of the Invention

[0005] The present invention aims to provide a solid-phase doped perovskite photodiode structure in order to address the shortcomings and deficiencies of existing perovskite photodiodes.

[0006] The technical solution adopted by the present invention is: a solid-phase doped perovskite photodiode, comprising a perovskite photon absorber, a first doped metal layer, a second doped metal layer, a first electrode layer and a second electrode layer;

[0007] A first doped metal layer and a second doped metal layer are deposited on both sides of the perovskite photon absorber, wherein the first doped metal layer is used to obtain n-type doping and the second doped metal layer is used to obtain p-type doping; metal ions of the first doped metal layer and the second doped metal layer penetrate into the perovskite photon absorber to form a perovskite n-type layer and a perovskite p-type layer;

[0008] A first electrode layer and a second electrode layer are deposited on both sides of the first doped metal layer and the second doped metal layer, respectively, for applying a bias voltage of the detector and collecting photocurrent, thereby forming a perovskite homojunction photodiode.

[0009] Preferably, the optical band gap of the perovskite photon absorber is between 0.8 eV and 4.2 eV.

[0010] Preferably, in the solid-phase doped perovskite photodiode of the present invention, the perovskite photon absorber can be an intrinsic perovskite material, such as MAPbBr 2.5 Cl 0.5 etc., and thereby construct a perovskite homogeneous pin junction; it can also be a p-type perovskite, such as MAPbBr3, etc., or an n-type perovskite, such as MAPbCl3, etc., and thereby construct a perovskite homogeneous pn junction.

[0011] Preferably, the perovskite photon absorber is a perovskite thin film or a perovskite single crystal.

[0012] Preferably, the perovskite photon absorber can be a perovskite film, which can be prepared on a substrate by a one-step method or a multi-step method; or a perovskite single crystal can be grown without a substrate by a solution inversion method or an antisolvent method, and the required size can be obtained by mechanical cutting.

[0013] Preferably, in order to achieve n-type doping, the first doping metal layer is deposited with Bi, Mn, Cu, Sb, Mg metal as a doping layer, and the perovskite photon absorber is doped with Bi 3+ 、Mn 2+ 、Cu 2+ 、Sb 3+ Mg 2+ Metal ions form the perovskite n-type layer; in order to achieve p-type doping, the second doping metal layer is deposited with Ag, Cs, Li, In, Ba metals as the doping layer, and the perovskite photon absorber is doped with Ag. + 、Cs + 、Li + 、In 3+ 、Ba 2+ metal ions, forming a perovskite p-type layer.

[0014] Preferably, in the solid-phase doped perovskite photodiode of the present invention, heating is used to allow metal ions in the doped metal layer to diffuse into the perovskite photon absorber, and electric field induction is used to accelerate the diffusion of the metal ions. These metal ions replace the halogen ions in the perovskite photon absorber, thereby forming the doping.

[0015] Preferably, in the solid-phase doped perovskite photodiode described herein, the doped metal layer undergoes solid-phase ion diffusion, which degrades its film uniformity and conductivity. Therefore, an electrode layer is deposited outside the doped metal layer. By manipulating the metal work function of the electrode layer, an ohmic electrical contact is established between the electrode layer and the perovskite photon absorber, ensuring good carrier transport.

[0016] The solid-phase doped perovskite photodiode proposed in the present invention first uses conventional methods to prepare a perovskite film or perovskite crystal, which serves as a photon absorber. A metal doping layer is then deposited at each end of the perovskite photon absorber. Heat and electric field induction are used to induce metal ions in the metal doping layer to migrate toward the perovskite photon absorber, thereby doping the perovskite photon absorber with metal ions. Because the perovskite photon absorber can be modified to an n-type or p-type state after being doped with metal ions, the present invention uses solid-phase doping to obtain a perovskite homogeneous pn or pin junction. Finally, collecting electrodes are deposited at both ends of the perovskite homojunction to form a perovskite photodiode.

[0017] It can be seen from the above technical solution that the solid-phase doped perovskite photodiode of the present invention has the following beneficial effects:

[0018] (1) The solid-phase doped perovskite photodiode proposed in the present invention constitutes a perovskite homojunction, so the interface lattice of the junction region is matched and the interface defect density is low, which helps to improve the detection quantum efficiency while reducing noise and dark current.

[0019] (2) In the solid-phase doped perovskite photodiode proposed in this invention, metal ions diffuse into the perovskite photon absorber through the solid phase, and the diffusion process is relatively easy to control. The doping depth can be controlled to be between tens and hundreds of nanometers, which is similar to the absorption depth of infrared, visible, and ultraviolet photons. Therefore, it is very suitable for infrared, visible, and ultraviolet light detection.

[0020] (3) The solid-phase doped perovskite photodiode proposed in the present invention has a simple preparation process. The entire detector can be prepared only through spin coating, inkjet printing, sputtering and evaporation coating processes, and the preparation cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a schematic structural diagram of a solid-phase doped perovskite photodiode according to the present invention;

[0022] Figure 2 The solid-phase doped perovskite PIN homojunction thin film photodiode proposed by the present invention;

[0023] Figure 3 The solid-phase doped perovskite single crystal homojunction photodiode proposed by the present invention;

[0024] Figure 4 A solid-phase doped perovskite pn homojunction thin film photodiode proposed by the present invention;

[0025] Figure 5 This is another solid-phase doped perovskite pn homojunction thin film photodiode proposed by the present invention;

[0026] Figure 6 The present invention proposes Ag for EDX characterization + A typical metal ion diffusion curve of solid-phase doped perovskite MAPbBr3;

[0027] In the figure: 1—transparent substrate; 2—second electrode layer; 3—second doped metal layer; 4—perovskite p-type layer; 5—intrinsic perovskite photon absorber; 6—perovskite n-type layer; 7—first doped metal layer; 8—first electrode layer; 9—p-type perovskite photon absorber; 10—n-type perovskite photon absorber. DETAILED DESCRIPTION

[0028] The present invention is described in detail below. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process. However, the protection scope of the present invention is not limited to the following embodiments.

[0029] like Figure 1 and 2 As shown, a second electrode layer 2 is first deposited on a transparent substrate 1 (such as glass or plastic), and then a second doped metal layer 3 is deposited on the second electrode layer 2. The second doped metal layer 3 is used to provide acceptor impurities to the perovskite photon absorber and can be a metal such as Ag, Cs, Li, In, or Ba. A perovskite thin film is prepared on the second doped metal layer 3 and serves as the intrinsic perovskite photon absorber 5. A first doped metal layer 7 is deposited on the intrinsic perovskite photon absorber 5. The first doped metal layer 7 is used to provide donor impurities to the intrinsic perovskite photon absorber 5 and can be a metal such as Bi, Mn, Cu, Sb, or Mg. The intrinsic perovskite photon absorber 5 is doped by heating and diffusing the doped metal layer and by electric field-induced ion migration, thereby forming a perovskite p-type layer 4 and a perovskite n-type layer 6 at its upper and lower ends, respectively.

[0030] The present invention can also directly use perovskite single crystal as the detector support, omitting the transparent substrate, such as Figure 3 As shown. First, a perovskite single crystal is obtained as an intrinsic perovskite photon absorber 5 through solution crystallization, and then mechanically cut to the required size. A second doped metal layer 3 and a first doped metal layer 7 are deposited on the upper and lower ends of the perovskite single crystal, respectively. Through heating diffusion and electric field-induced ion migration, the intrinsic perovskite photon absorber 5 is doped, and a perovskite p-type layer 4 and a perovskite n-type layer 6 are obtained at the upper and lower ends, respectively. A first electrode layer 8 and a second electrode layer 2 are deposited on the outer sides of the second doped metal layer 3 and the first doped metal layer 7, respectively.

[0031] The solid-phase doped perovskite photodiode proposed in the present invention can also adopt a homogeneous pn junction. Taking a thin film photodiode as an example, Figure 4 As shown, a second electrode layer 2 is first formed on a transparent substrate 1, and then a p-type perovskite thin film is formed thereon. A first doped metal layer 7 is deposited on the p-type perovskite photon absorber 9. Heat diffusion and electric field-induced ion migration form a perovskite n-type layer 6. A first electrode layer 8 is deposited on the first doped metal layer 7.

[0032] Figure 5 This is another form of the solid-phase doped pn-junction perovskite photodiode proposed in the present invention. A second electrode layer 2 is first deposited on a transparent substrate 1, followed by a second doped metal layer 3. An n-type perovskite photon absorber 10 is formed on the second doped metal layer 3. Heat diffusion and electric field-induced ion migration form a perovskite p-type layer 4. A first electrode layer 8 is then deposited on the n-type perovskite photon absorber 10.

[0033] The present invention provides a method for preparing a solid-phase doped perovskite photodiode, comprising the following steps:

[0034] Electrode layer preparation: The metal electrode layer can be prepared by vacuum evaporation or sputtering to ensure ohmic electrical contact with the perovskite photon absorber.

[0035] Preparation of a doped metal layer. The purpose of the doped metal layer is to provide donor and acceptor impurities to the perovskite photon absorber. The conductive properties of the metal layer are not required. Amorphous metal films can be formed by vacuum evaporation or sputtering, or by spin-coating metal nanoparticles.

[0036] Preparation of perovskite photon absorbers. If perovskite thin films are used as photon absorbers, conventional one-step or two-step methods can be used to prepare the perovskite thin films. If perovskite single crystals are used as photon absorbers, the antisolvent method or inversion temperature method can be used to grow the perovskite single crystals.

[0037] Diffusion of metal ions. The present invention utilizes heated diffusion and electric field-induced ion migration. Considering the temperature tolerance of perovskite materials, the heating temperature is generally between 100°C and 150°C. Because metal ions are positively charged, the direction of the applied induced electric field aligns with the migration direction of the metal ions. This method of heated diffusion and electric field-induced solid-phase metal ion doping allows for precise control of the process, maintaining the doping depth below 1 micron, suitable for infrared, visible light, and ultraviolet detection. Figure 6 It is a typical heating diffusion and electric field induced Ag + EDX (Energy Dispersive X-ray Fluorescence Spectroscopy) scanning line of diffusion doping into MAPbBr3 crystal, from which we can see Ag + The doping depth is about 50nm.

[0038] The present invention proposes a solid-phase doped perovskite photodiode structure and its preparation method, which achieves a homogeneous perovskite pn junction or pin junction through solid-phase doping. Compared with perovskite heterojunctions prepared by methods such as spin coating, the perovskite homojunction proposed in the present invention has a lattice-matched junction interface and fewer interface defects, thereby improving the photodiode's detection quantum efficiency and reducing defect-induced shot noise. Compared with perovskite homogeneous pn junctions or pin junctions prepared by solution-based liquid-phase doping, the depletion layer thickness of the perovskite pn junction or pin junction prepared by solid-phase doping can be controlled to less than 1 micron, making it more suitable for infrared, visible, and ultraviolet light detection.

[0039] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A solid-phase doped perovskite photodiode, characterized in that: comprising a perovskite photon absorber, a first doped metal layer, a second doped metal layer, a first electrode layer, and a second electrode layer; A first doped metal layer and a second doped metal layer are deposited on both sides of the perovskite photon absorber, wherein the first doped metal layer is used to obtain n-type doping and the second doped metal layer is used to obtain p-type doping; metal ions of the first doped metal layer and the second doped metal layer penetrate into the perovskite photon absorber to form a perovskite n-type layer and a perovskite p-type layer; A first electrode layer and a second electrode layer are deposited on both sides of the first doped metal layer and the second doped metal layer, respectively, for applying a bias voltage of the detector and collecting photocurrent, thereby forming a perovskite homojunction photodiode.

2. The solid-phase doped perovskite photodiode according to claim 1, characterized in that: The optical band gap of the perovskite photon absorber is between 0.8 eV and 4.2 eV.

3. The solid-phase doped perovskite photodiode according to claim 1, characterized in that: The perovskite photon absorber is an intrinsic perovskite material, thereby constructing a perovskite homogeneous pin junction; or a p-type perovskite; or an n-type perovskite, thereby constructing a perovskite homogeneous pn junction.

4. The solid-phase doped perovskite photodiode according to claim 3, characterized in that: The intrinsic perovskite material is a typical intrinsic perovskite material, and MAPbBr is selected. 2.5 Cl 0.5 The p-type perovskite is a typical p-type perovskite, selected as MAPbBr3, and the n-type perovskite is a typical n-type perovskite, selected as MAPbCl3.

5. The solid-phase doped perovskite photodiode according to claim 1, characterized in that: The perovskite photon absorber is a perovskite thin film or a perovskite single crystal.

6. The solid-phase doped perovskite photodiode according to claim 5, characterized in that: The perovskite photon absorber is a perovskite film, which is prepared on a substrate by a one-step method or a multi-step method; or a perovskite single crystal is grown without a substrate by a solution inversion method or an antisolvent method, and the required size is obtained by mechanical cutting.

7. The solid-phase doped perovskite photodiode according to claim 1, characterized in that: In order to achieve n-type doping, the first doping metal layer deposits Bi, Mn, Cu, Sb, and Mg metals as the doping layer, and the perovskite photon absorber is doped with Bi 3 + 、Mn 2+ 、Cu 2+ 、Sb 3+ Mg 2+ Metal ions form the perovskite n-type layer; in order to achieve p-type doping, the second doping metal layer is deposited with Ag, Cs, Li, In, Ba metals as the doping layer, and the perovskite photon absorber is doped with Ag. + 、Cs + 、Li + 、In 3+ 、Ba 2+ metal ions, forming a perovskite p-type layer.

8. The solid-phase doped perovskite photodiode according to claim 1, characterized in that: The metal ions in the first doped metal layer and the second doped metal layer are allowed to diffuse into the perovskite photon absorber by heating, and the diffusion process of the metal ions is accelerated by electric field induction.

9. The solid-phase doped perovskite photodiode according to claim 1, characterized in that: The first electrode layer, the second electrode layer and the perovskite photon absorber form an ohmic electrical contact.

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