Perovskite semiconductor that can achieve p-type, n-type and i-type conductivity by means of doping

Abstract

A perovskite semiconductor material that can achieve p-type, n-type and i-type conductivity by means of doping. The doped perovskite semiconductor material can be divided into a p-type perovskite semiconductor, an n-type perovskite semiconductor and an i-type (intrinsic) perovskite semiconductor on the basis of the conduction type. The perovskite semiconductor material characteristics are adjustable, and the doped perovskite semiconductor material component is A'2An-1BnX3n+1:D or ABX3:D, wherein A' is an organic cation, A is a monovalent cation, B is a metal cation, X is a monovalent anion, and D is a dopant. An optoelectronic device based on the doped perovskite semiconductor material can get rid of the dependence on an electron transport layer or a hole transport layer, thereby simplifying the device process, and reducing the complexity and costs of the preparation of the device. Light-emitting diodes, solar cells, and transistors based on the controllably doped perovskite semiconductor material exhibit excellent performance.

Description

A perovskite semiconductor that can be doped to achieve p-type, n-type, and i-type conductivity Technical Field

[0001] The present invention relates to the technical field of semiconductor materials and devices, and in particular to a perovskite semiconductor capable of achieving p-type, n-type and i-type conductivity through doping. Technical Background

[0002] Reliable control of the electrical polarity and conductivity of semiconductors is a core technology of the modern electronics industry, leading to revolutionary inventions such as diodes, transistors, solar cells, photodetectors, light-emitting diodes, and semiconductor lasers. Taking silicon, a traditional semiconductor material, as an example, silicon can be doped into either n-type (electrons as the primary charge carrier) or p-type (holes as the primary charge carrier) by introducing electron acceptors (such as boron) or electron donors (such as phosphorus) into its crystal lattice. This allows for the manipulation of electrical transmission properties and, by leveraging the rectifying properties of the pn junction, enables the realization of a variety of electronic and optoelectronic devices. Perovskite materials are a new type of ionic crystal semiconductor with a crystal structure, including but not limited to cubic structures, in which different ions are held together by interionic forces. These materials offer advantages such as continuously tunable band gaps, easy carrier diffusion, solution-processable processing, strong light absorption, high luminescence quantum efficiency, and spectrally pure luminescence. However, due to the complexity and unique nature of their crystal structure, controllable electrical doping of perovskites is difficult to achieve, hindering their further development and application in the semiconductor industry. Since their first report in 2009, perovskite solar cells have seen rapid growth in efficiency, now exceeding 26%. However, they still lag behind traditional inorganic silicon cells in terms of stability and energy conversion efficiency. Furthermore, perovskite is a highly luminescent material that can be prepared using a solution process. In 2014, their use in perovskite light-emitting diodes (LEDs) was first reported, marking the beginning of research on perovskite LEDs and garnering widespread attention. Their efficiency has now exceeded 30%, comparable to inorganic and organic light-emitting diodes. However, controllable electrical doping of perovskite semiconductors has yet to be achieved, making precise control of their conductivity type and electrical properties difficult, hindering further development in the field of perovskite semiconductors and optoelectronic devices.Controllable doping of perovskite semiconductor materials has many advantages: 1. It can precisely control the conductivity type (polarity), resistivity, conductivity, carrier concentration, carrier mobility, Fermi level, band position and photoelectric properties of perovskite semiconductor materials; 2. It can realize the design and development of a series of p-type, n-type and i-type perovskite semiconductor materials, and design and prepare homojunctions or heterojunctions with different functions based on one or more perovskite semiconductor materials, which further expands the building blocks of perovskite devices and helps realize a variety of new perovskite semiconductor devices, including but not limited to 3. Controllable doping of perovskite semiconductor materials can free perovskite devices from reliance on transport layer materials, enabling the realization of perovskite optoelectronic devices without hole or electron transport layers. This significantly simplifies the preparation conditions for perovskite devices, reduces costs, and improves product reproducibility and yield. 4. Controllable doping strategies for perovskite semiconductor materials can greatly enrich the types of perovskite semiconductor materials, enabling them to possess performance comparable to or exceeding that of traditional semiconductors (such as silicon and III-V semiconductors). Therefore, the controllable doping of perovskite semiconductors achieved by this invention is crucial to the development of the emerging field of perovskite semiconductors and optoelectronic devices, promising unprecedented device performance and accelerating the creation of new semiconductor devices.

[0003] Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a perovskite semiconductor that can achieve p-type, n-type and i-type conductivity through doping.

[0005] As an emerging semiconductor material, the structure and composition of perovskite semiconductors are relatively complex. Controllable electrical doping of perovskite semiconductors has not yet been achieved, and it is difficult to precisely control their conductivity type and electrical properties, which has restricted the further development of perovskite semiconductors and optoelectronic devices. In response to this important technical problem, the present invention realizes controllable doping of perovskite semiconductor materials and optoelectronic devices thereof. Doped perovskite semiconductor materials can be further divided into p-type perovskites with holes as the main conductive medium, n-type perovskites with electrons as the main conductive medium, and i-type perovskites with bipolar transmission. The components of the doped perovskite material are A'2A n-1 B n X 3n+1:D (n = 1, 2, 3, ...) or ABX3:D, where A' is an organic cation, A is a monovalent cation, B is a metal cation, X is a monovalent anion, and D is a dopant (based on the metal cation B, the molar ratio of D to B ranges from 0% to 80%). Dopants are divided into p-type dopants and n-type dopants based on their doping effect. P-type dopants can inhibit the formation of electron-donating energy levels in perovskite materials or exhibit electron-withdrawing effects, thereby achieving perovskite semiconductor materials with enhanced p-type semiconductor characteristics or weakened n-type semiconductor characteristics. N-type dopants can inhibit the formation of electron-accepting energy levels in perovskite materials or exhibit electron-donating effects, thereby achieving perovskite semiconductor materials with enhanced n-type semiconductor characteristics or weakened p-type semiconductor characteristics. The structural characteristics of the dopant are that it contains a functional group with a lone pair of electrons or its functional group can provide an empty electron orbit or can be ionized to generate ions to partially replace the position of a certain ion in the perovskite crystal, so that the dopant can react with the ions in the perovskite crystal structure, including but not limited to coordination, covalent bonding, interionic interaction and hydrogen bonding, thereby achieving the above-mentioned doping effect. Dopants can be divided into types including but not limited to organic polymer materials, organic small molecule materials, organic salts, inorganic salts, Lewis acids, Lewis bases, etc. The preparation method and doping method of controllable doped perovskite semiconductor materials include but are not limited to: 1. Dissolving A'X (one or more), AX (one or more), BX (one or more) and dopant in a solvent to obtain a perovskite precursor solution, and preparing the doped perovskite material by a solution method; 2. Dissolving A'X (one or more), AX (one or more), BX (one or more) in a solvent to obtain a perovskite precursor solution and preparing a perovskite material, and the dopant is treated by anti-solvent treatment, surface modification, solution fumigation, solid-state diffusion, plasma evaporation, etc. 3. A'X (one or more), AX (one or more), BX (one or more) are prepared into perovskite by non-solution methods such as magnetron sputtering, solid-state reaction, vapor deposition, evaporation, etc. to form a perovskite semiconductor material, and the dopant is introduced into the perovskite by a doping process such as anti-solvent treatment, surface modification, solution fumigation, solid-state diffusion, plasma injection, etc. to obtain a doped perovskite semiconductor material; 4. A combination of two or more of the above processes is used to prepare a doped perovskite semiconductor material. One or more of the different doped perovskite semiconductor materials prepared by the above dopants and methods can form homojunctions or heterojunctions with different functions, enriching the building blocks of perovskite electronic or optoelectronic devices, and can be used to prepare perovskite electronic or optoelectronic devices including but not limited to diodes, transistors, solar cells, detectors, scintillators, light-emitting diodes, semiconductor lasers, etc.The perovskite electronic or optoelectronic device is composed of a doped perovskite material and one or more of the following device functional materials: a substrate, an anode, an electron transport material, a hole transport material, a cathode, etc. Doped perovskite semiconductors can eliminate the need for complex electron or hole transport layers, thus enabling the realization of layer-less perovskite optoelectronic devices. Such devices have a simpler fabrication process, reducing the complexity and cost of device fabrication and improving the repeatability and yield of device fabrication.

[0006] The technical solutions of the present invention are as follows:

[0007] The present invention discloses a controllably doped perovskite material, a doping method, and an optoelectronic device thereof. The general structural formula of the perovskite semiconductor material is D:A'2A n-1 B n X 3n+1 (n=1,2,3,…) or D:ABX3, where A' is an organic cation; A is a monovalent cation, such as cesium ion (Cs + ), methylamine ion (MA + ), methylamine ion (FA + ), ethylamine ion (EA + ), hydrazine ion (HA + ), guanidine ion (GA + ), isopropylamine ion (IPA + ), imidazolium ion (IA + ) etc. B is a metal cation, such as lead ion (Pb 2+ ), tin ions (Sn 2+ ), Germanium ions (Ge 2+ ) etc.; X is an anion including: chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I - ) etc., D is a dopant.

[0008] P-type perovskite semiconductor refers to a perovskite material in which the majority carriers responsible for conduction are holes, exhibiting p-type transport characteristics; n-type perovskite semiconductor refers to a perovskite material in which the majority carriers responsible for conduction are electrons, exhibiting n-type transport characteristics; i-type perovskite semiconductor refers to a perovskite material in which the concentration of electrons and holes responsible for conduction is equal, exhibiting insulating properties or bipolar transport characteristics; its semiconductor band gap width is adjustable, and its band gap is generally in the range of 0.5eV–4eV; at room temperature, its carrier concentration is 10 10 cm -3 -10 20 cm -3 range; at room temperature, its carrier mobility is 10 -4 cm 2 V -1s -1 –1000cm 2 V -1 s -1 range; its fluorescence quantum yield is in the range of 0.1%-95%; by introducing dopants into the perovskite semiconductor, the above-mentioned electrical properties or photoelectric properties can be reliably regulated.

[0009] The dopants include but are not limited to organic polymer materials, organic small molecule materials, organic salts, inorganic salts, Lewis bases and Lewis acids. Dopants that inhibit the formation of electron-donating energy levels or have electron-withdrawing effects can make the perovskite material exhibit p-type doping enhancement or n-type doping weakening characteristics; dopants that inhibit the formation of electron-accepting energy levels or have electron-donating effects can make the perovskite material exhibit n-type doping enhancement or p-type doping weakening characteristics; using one or more dopants at the same time to balance the formation of electron-donating energy levels and electron-accepting energy levels in the perovskite material, as well as balancing the electron-withdrawing and electron-donating effects of the dopants, can be used to prepare i-type (intrinsic) perovskite semiconductors that exhibit insulating properties or bipolar transmission properties. The preparation method and doping method of controllably doped perovskite semiconductor materials can be a combination of one or more of the following preparation methods. A'X (one or more), AX (one or more), BX (one or more) and a dopant are dissolved in a solvent to obtain a perovskite precursor solution, and a doped perovskite material can be prepared by a solution method; A'X (one or more), AX (one or more), and BX (one or more) are dissolved in a solvent to obtain a perovskite precursor solution and prepared into a perovskite material, and the dopant is introduced into the perovskite through a doping process such as anti-solvent treatment, surface modification, solution fumigation, solid-state diffusion, and plasma injection to obtain a doped perovskite semiconductor material; A'X (one or more), AX (one or more), and BX (one or more) are prepared into a perovskite semiconductor material through a non-solution method such as magnetron sputtering, solid-state reaction, vapor deposition, and evaporation, and the dopant is introduced into the perovskite through a doping process such as anti-solvent treatment, surface modification, solution fumigation, solid-state diffusion, and plasma injection to obtain a doped perovskite semiconductor material. The physical form of the perovskite semiconductor obtained by this preparation and doping method may include but is not limited to polycrystalline thin films, single crystals, nanocrystals, quantum dots, nanowires, nanosheets, and mixed materials of the above perovskite materials with one or more organic small molecules, polymers, metal oxides, Group III-V semiconductors, Group II-VI semiconductors, metals, inorganic dielectrics, nanomaterials, etc.In the preparation and doping methods, the dopant includes but is not limited to the following compounds, which can be any one of the following or a mixture in any proportion: (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid (ME-2PACz), [2-(3,6-dibromo-9H-carbazole-9-yl)ethyl]phosphonic acid (B r-2PACz), [4-(9H-carbazol-9-yl)butyl]phosphonic acid (4PACz), [4-(3,6-dibromo-9H-carbazol-9-yl)butyl]phosphonic acid (Br-4PACz), [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (ME-4PACz), 3-(carbazol-9-yl)propionic acid, potassium bromide, sodium bromide, rubidium bromide, europium bromide, etc. Common functional groups containing lone pairs of electrons in the organic dopant molecules and common functional groups in Lewis bases include, but are not limited to, phosphoric acid group (-PO(OH)2), phosphoryl chloride group (-P(O)Cl2), phosphoryl group (-P(O)R2), organic phosphate group (-OP(O)(OR)2), sulfonic acid group (-SO3H), thioketone group (-S(=O)-R), amino group (-NH2), hydroxyl group (-OH), cyano group (-CN), aldehyde group (-CHO), carboxyl group (-COOH), ketone group (-C=OR), and nitrogen nitrile group (-N≡C). Common functional groups containing empty electron orbitals in the organic dopant molecules and common functional groups in Lewis acids include, but are not limited to, carbon-carbon double bond group (-C=C), carbon-carbon triple bond group (-C≡C), and boric acid (BF3). Common ions in the inorganic dopant molecules include, but are not limited to, sodium ion (Na. + ), potassium ion (K + ), rubidium ions (Rb + ), europium ions (Eu 2+ ), strontium ions (Sr 2+ ), silver ions (Ag + )Indium ions (In 2+ ), and bismuth ions (Bi 2+ )wait.

[0010] Electronic and optoelectronic devices based on controllably doped perovskite semiconductor materials typically consist of a doped perovskite material and one or more of the following device functional materials: a substrate, an anode, an electron transport material, a hole transport material, a cathode, and so on. These devices include, but are not limited to, diodes, transistors, solar cells, detectors, scintillators, light-emitting diodes, and semiconductor lasers. Functionally diverse homojunctions or heterojunctions composed of one or more doped perovskite semiconductor materials are also important building blocks for these electronic or optoelectronic devices. The realization of controllably doped perovskite semiconductor materials has greatly enriched the types of such building blocks. Doped perovskite semiconductors can eliminate the need for electron or hole transport layers, thus enabling the realization of perovskite optoelectronic devices without transport layers. These devices have simpler fabrication processes, reducing the complexity and cost of device fabrication and improving the repeatability and yield of device fabrication. The maximum external quantum efficiency (EQE) of the light-emitting diode device based on doped perovskite semiconductor materials is in the range of 10%-30%, and the maximum external quantum efficiency after optimization can reach more than 30%; the electroluminescence peak wavelength is in the range of 300nm-2000nm; the maximum radiance is greater than 20W sr -1 m -2 (If it is a visible light emitting diode, the maximum brightness (luminance) is greater than 10000cd m -2 ), the optimized maximum radiance is greater than 2000W sr -1 m -2 (If it is a visible light emitting diode, the optimized maximum brightness is greater than 1000000cd m -2 ). The power conversion efficiency (PCE) of solar cell devices based on doped perovskite semiconductor materials is in the range of 10%-30% under single-junction cell configuration and 1-sun standard illumination conditions, and the power conversion efficiency after optimization can reach more than 30%; the fill factor (FF) is in the range of 60%-85%, and the fill factor after optimization can reach more than 85%. Using configurations such as multi-junction stacked cells, the power conversion efficiency can reach more than 35%. Transistor devices based on doped perovskite semiconductor materials have a carrier mobility greater than 10 at room temperature. -4 cm 2 V -1 s -1 , the optimized mobility can reach 100cm 2 V -1 s -1 or above.

[0011] When the hole concentration in p-type perovskite semiconductor reaches 10 18 cm -3When the electron concentration in the n-type perovskite semiconductor reaches 10 18 cm -3 The above may also be referred to as "heavily doped n-type perovskite semiconductor" or "n+ type perovskite semiconductor".

[0012] The present invention has the following beneficial effects:

[0013] (1) The present invention realizes controllable doping of p-type, n-type and i-type perovskite semiconductors, and achieves precise control of the conductivity type (polarity), resistivity, conductivity, carrier concentration, carrier mobility, Fermi level, band position and photoelectric properties of perovskite semiconductors.

[0014] (2) The present invention can be used to construct perovskite electronic or optoelectronic devices, including but not limited to diodes, transistors, solar cells, detectors, scintillators, light-emitting diodes, semiconductor lasers, etc.

[0015] (3) The present invention utilizes one or more p-type, n-type or i-type perovskite semiconductor materials to form a homojunction or heterojunction, thereby expanding the basic building blocks of perovskite devices and realizing a variety of new semiconductor devices.

[0016] (4) The controllably doped perovskite semiconductor material realized by the present invention can get rid of the dependence on the electron transport layer or the hole transport layer, and can realize perovskite electronic and optoelectronic devices without a transport layer. Such devices have a simpler preparation process, which can reduce the complexity and cost of device preparation and improve the repeatability and yield of device preparation.

[0017] (5) The controllably doped perovskite semiconductor materials and technologies involved in the present invention can achieve precise control of the electrical and optoelectronic properties of perovskite semiconductors, and can obtain perovskite electronic and optoelectronic devices with performance close to or exceeding that of traditional semiconductor devices (such as silicon, III-V semiconductors, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a crystal structure diagram of an undoped perovskite material in Example 1 of the present invention;

[0019] FIG2 is a crystal structure diagram of the doped perovskite material in Example 1 of the present invention;

[0020] FIG3 is a diagram showing the current density-voltage characteristics of a perovskite light-emitting diode in Example 1 of the present invention;

[0021] FIG4 is a graph showing the radiance-voltage characteristics of a perovskite light-emitting diode in Example 1 of the present invention;

[0022] FIG4 is an energy level arrangement diagram of perovskite materials with different doping concentrations in Example 1 of the present invention;

[0023] FIG5 is a Darwin probe microscope image of the surface of an undoped perovskite film in Example 1 of the present invention;

[0024] FIG. 6 shows a 1% doping concentration (dopant relative to Pb) in Example 1 of the present invention. 2+ ) of the perovskite film surface;

[0025] FIG. 7 shows a 3% doping concentration (dopant relative to Pb) in Example 1 of the present invention. 2+ ) of the perovskite film surface;

[0026] FIG8 shows a 5% doping concentration (dopant relative to Pb) in Example 1 of the present invention. 2+ ) of the perovskite film surface;

[0027] FIG9 is a schematic diagram of the surface contact potential difference of the perovskite film with different doping concentrations in Example 1 of the present invention;

[0028] FIG10 is a Hall coefficient test result of perovskite materials with different doping concentrations in Example 1 of the present invention;

[0029] FIG11 shows the main carrier types and density test results of perovskite materials with different doping concentrations in Example 1 of the present invention;

[0030] FIG12 is a theoretical calculation model of the undoped perovskite material in Example 2 of the present invention.

[0031] FIG13 is a theoretical calculation model of the doped perovskite material in Example 2 of the present invention.

[0032] FIG14 shows the calculation results of the formation energy of different defects in the undoped perovskite in Example 2 of the present invention.

[0033] FIG15 is a diagram showing the electron cloud density distribution of undoped perovskite in Example 2 of the present invention.

[0034] FIG16 is a diagram showing the electron cloud density distribution of the doped perovskite in Example 2 of the present invention.

[0035] FIG. 17 shows the perovskite state density before and after doping in Example 2 of the present invention / (EE V )picture.

[0036] FIG18 is a schematic diagram of the perovskite doping mechanism based on density functional calculation results in Example 2 of the present invention.

[0037] FIG19 is a nuclear magnetic resonance spectrum of 4PACz with or without the addition of PbBr2 in Example 2 of the present invention.

[0038] FIG20 is a Fourier transform infrared absorption spectrum of 4PACz and doped perovskite materials in Example 2 of the present invention.

[0039] FIG21 is an X-ray photoelectron spectrum of the undoped and doped perovskite materials in Example 2 of the present invention.

[0040] FIG22 is a structural diagram of a perovskite light-emitting diode device without a hole transport layer in Example 3 of the present invention.

[0041] FIG23 is a transmission electron microscope image of the cross section of a perovskite light-emitting diode without a hole transport layer in Example 3 of the present invention.

[0042] FIG24 is a performance comparison diagram of light-emitting diode devices without a hole transport layer based on perovskites with different doping concentrations in Example 3 of the present invention.

[0043] FIG25 is a graph showing the emission spectra of the perovskite light-emitting diode without a hole transport layer based on undoped and 5% doped conditions in Example 3 of the present invention.

[0044] FIG26 is a current density-voltage curve of the perovskite light-emitting diode without a hole transport layer based on undoped and 5% doped examples in Example 3 of the present invention.

[0045] FIG27 is a brightness-voltage curve of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped structure in Example 3 of the present invention.

[0046] FIG28 is an external quantum efficiency-brightness curve of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped structure in Example 3 of the present invention.

[0047] FIG29 is a graph showing the energy conversion efficiency-brightness curves of the undoped and 5% doped perovskite light-emitting diodes without a hole transport layer in Example 3 of the present invention.

[0048] FIG30 is a statistical diagram of the photoluminescence efficiency of perovskite films with different doping concentrations in Example 3 of the present invention.

[0049] FIG31 is a transient photoluminescence spectrum of the undoped and 5% doped perovskite films in Example 3 of the present invention. DETAILED DESCRIPTION

[0050] Figure 1 shows the crystal structure of an undoped perovskite material; Figure 2 shows the crystal structure of a doped perovskite material. The unsaturated B sites in the perovskite can interact with the acidic groups in the dopant. The dopant provides electron-donating or electron-withdrawing groups to the perovskite material, suppressing the amount of unsaturated lead in the perovskite and thus the formation of electron-donating or electron-accepting energy levels caused by related defects. This regulates the type (electrons or holes) and amount of the primary carriers in the perovskite material, and thus the conductivity of the perovskite material. After fine-tuning the doping process, the perovskite material can achieve the appropriate carrier mobility and carrier density, enabling the successful fabrication of high-efficiency, high-brightness light-emitting diodes without a hole or electron transport layer.

[0051] (1) Prepare perovskite precursor solution

[0052] The perovskite precursor solution is prepared by dissolving A'X, AX, BX2, and dopant P in a solvent (which can be any one or a mixed solvent such as DMF, DMSO, GBL, NMP, acetonitrile, G-butyrolactone, etc.), wherein A' is an organic amine cation, A is a monovalent cation, such as a cesium ion (Cs + ), methylamine ion (MA + ), methylamine ion (FA + ), ethylamine ion (EA + ), hydrazine ion (HA + ), guanidine ion (GA + ), isopropylamine ion (IPA + ), imidazolium ion (IA + ) etc.; B-position divalent metal cations, such as lead ions (Pb 2+ ), tin ions (Sn 2+ ), Germanium ions (Ge 2+ ) etc.; X-position anions include: chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I - ) etc. The concentration of the perovskite precursor solution is 0.01-2 mol / L.

[0053] (2) Preparation of perovskite light-emitting diodes

[0054] The substrate is sequentially soaked in water, deionized water, acetone, and isopropyl alcohol. It is then cleaned in an ultrasonic machine for more than 15 minutes. Before spin coating, the ITO glass substrate is treated with a plasma machine for 15 minutes. The perovskite film is then prepared directly on the ITO using a solution method and annealed for a certain period of time. During the spin coating process, an anti-solvent such as chlorobenzene, toluene, ethyl acetate, anhydrous ether, chloroform, or any one or more mixed solvents is introduced. The electron or hole transport layer is then prepared by spin coating, evaporation, magnetron sputtering, atomic layer deposition, etc. Finally, the electrode layer is prepared by evaporation, magnetron sputtering, atomic layer deposition, etc.

[0055] 1. Example 1 Controllable Doping of Perovskite Materials

[0056] The perovskite precursor solution was prepared by dissolving FABr, MABr, GABr, CsBr, PbBr2, and dopant 4PACz in 1 ml of DMSO at a molar ratio of 0.8:0.1:0.1:0.15:1:x (x = 0-0.8) to prepare 0.95 mol L -1 A two-step spin coating method was used to prepare perovskite films on substrates including but not limited to ITO substrates, quartz glass substrates, sapphire substrates, and silicon wafers. The first spin coating step involved hanging coating at a rotation speed of 500 rpm for 10 seconds, and the second spin coating step involved hanging coating at a rotation speed of 5000 rpm for 90 seconds. Approximately 40 seconds after the start of the second spin coating step, 100 μL of an antisolvent containing 2 mg / ml TPBI in chloroform was added dropwise to the sample. After the spin coating step, the perovskite film was annealed at 90°C for 10 minutes.

[0057] As shown in Figure 3, the UV photoelectron spectroscopy test results of perovskite materials with different doping concentrations are shown. IP represents the ionization potential and WF represents the work function. As shown in Figure 4, the energy level arrangement diagram of perovskite materials with different doping concentrations is shown. V Represents the valence band bottom, E C Represents the top of the conduction band; as shown in Figure 5, it is a Darwin probe microscope image of the surface of the undoped perovskite film; the scale is 400nm. As shown in Figure 6, it is a 1% doping concentration (dopant relative to Pb 2+ ) of the perovskite film surface; the scale is 400nm. As shown in Figure 7, the doping concentration is 3% (dopant relative to Pb 2+ ) of the perovskite film surface; the scale is 400nm. As shown in Figure 8, the doping concentration is 5% (dopant relative to Pb 2+Darwin probe microscopy images of the perovskite film surface (Figure 9); the scale bar is 400 nm. Figure 9 shows a schematic diagram of the contact potential difference on the surface of perovskite films with different doping concentrations. Figure 10 shows the Hall coefficient test results for perovskite materials with different doping concentrations. Figure 11 shows the main carrier type and density test results for perovskite materials with different doping concentrations.

[0058] 2. Example 2: Establishment of perovskite material doping model and its mechanism study

[0059] First-principles calculations based on density functional theory were used to study the perovskite doping mechanism. The relevant model was successfully established, and a series of calculations were performed on this basis. Figure 12 is the theoretical calculation model of the undoped perovskite material. Figure 13 is the theoretical calculation model of the doped perovskite material; Figure 14 is the calculation results of the formation energy of different defects in the undoped perovskite; Figure 15 is the electron cloud density distribution of the undoped perovskite; Figure 16 is the electron cloud density distribution of the doped perovskite; Figure 17 is the perovskite neutral state density / (EE) before and after doping. V ) Figure 18 is a schematic diagram of the perovskite doping mechanism based on density functional calculation results; Figure 19 is the nuclear magnetic resonance spectrum of 4PACz with or without the addition of PbBr2; Figure 20 is the Fourier transform infrared absorption spectrum of 4PACz and doped perovskite materials; Figure 21 is the X-ray photoelectron spectrum of undoped and doped perovskite materials.

[0060] 3. Example 3 Preparation of a Perovskite Light-Emitting Diode Without a Hole Transport Layer

[0061] The substrate was soaked in water, deionized water, acetone, and isopropanol in sequence and cleaned in an ultrasonic machine for more than 15 minutes. Before spin coating, the substrate was treated with a plasma machine for 15 minutes. The perovskite precursor solution was prepared by dissolving FABr, MABr, GABr, CsBr, PbBr2, and dopant 4PACz in 1 ml of DMSO at a molar ratio of 0.8:0.1:0.1:0.15:1:x (x = 0-0.8) to prepare 0.95 mol L -1A two-step spin coating method was used to deposit perovskite thin films on substrates including but not limited to ITO, quartz glass, sapphire, and silicon wafers. The first spin coating step involved 10 seconds at a rotation speed of 500 rpm, and the second spin coating step involved 90 seconds at a rotation speed of 5000 rpm. Approximately 40 seconds after the start of the second spin coating step, 100 μL of an antisolvent (chloroform containing 2 mg / ml TPBI) was added dropwise to the sample. After spin coating, the perovskite film was annealed at 90°C for 10 minutes. The electron transport layer was made of PO-T2T, and the electrode material was Yb / Ag. As shown in Figure 22, a device structure diagram of a perovskite light-emitting diode without a hole transport layer is shown; Figure 23 is a transmission electron micrograph of a cross-section of a perovskite light-emitting diode without a hole transport layer; Figure 24 is a performance comparison diagram of light-emitting diode devices without a hole transport layer based on perovskites with different doping concentrations; Figure 25 is a luminescence spectrum diagram of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped perovskite; Figure 26 is a current density-voltage curve of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped perovskite; Figure 27 is a brightness-voltage curve of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped perovskite; Figure 28 is an external quantum efficiency-brightness curve of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped perovskite; Figure 29 is an energy conversion efficiency-brightness curve of a perovskite light-emitting diode without a hole transport layer based on an undoped and 5% doped perovskite; Figure 30 is a statistical diagram of the photoluminescence efficiency of perovskite films with different doping concentrations; and Figure 31 is a transient photoluminescence spectrum diagram of a perovskite film based on an undoped and 5% doped perovskite.

Claims

1. A perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping, characterized in that: The composition of the doped perovskite material is A'2A n-1 B n X 3n+1 :D or ABX3:D, where n=1,2,3,…, A' is an organic cation, A is a monovalent cation, B is a metal cation, X is a monovalent anion, and D is a dopant. The molar ratio of D to B is in the range of 0%-80% based on the metal cation B. A p-type perovskite semiconductor refers to a perovskite material in which the majority carriers responsible for conduction are holes, exhibiting p-type transport characteristics. An n-type perovskite semiconductor refers to a perovskite material in which the majority carriers responsible for conduction are electrons, exhibiting n-type transport characteristics. An i-type perovskite semiconductor refers to a perovskite material in which the concentrations of electrons and holes responsible for conduction are equivalent, exhibiting insulating characteristics or bipolar transport characteristics. The semiconductor band gap is adjustable, and its band gap is generally in the range of 0.5eV–4eV. At room temperature, its carrier concentration is 10 10 cm -3 -10 20 cm -3 range; at room temperature, its carrier mobility is 10 -4 cm 2 V -1 s -1 –1000cm 2 V -1 s -1 range; its fluorescence quantum yield is in the range of 0.1%-95%; by introducing dopants into the perovskite semiconductor, the above-mentioned electrical properties or photoelectric properties can be reliably regulated.

2. The perovskite semiconductor according to claim 1, wherein: Dopants that can make perovskite semiconductors exhibit p-type characteristics, enhance p-type characteristics, or weaken n-type characteristics after doping are p-type perovskite dopants; dopants that can make perovskite semiconductors exhibit n-type characteristics, enhance n-type characteristics, or weaken p-type characteristics after doping are n-type perovskite dopants; among them, p-type perovskite dopants exhibit the ability to gain electrons in perovskite materials, and are electron acceptors, i.e., acceptors, providing more holes for perovskite semiconductors, causing their Fermi energy levels to move toward the valence band; n-type perovskite dopants exhibit the ability to lose electrons in perovskite materials, and are electron donors, i.e., donors, which are calcium Titanium ore semiconductors provide more electrons, causing their Fermi level to move toward the conduction band; introducing n-type perovskite dopants into p-type perovskite can realize i-type or n-type perovskite semiconductors; introducing p-type perovskite dopants into n-type perovskite can realize i-type or p-type perovskite semiconductors; when doping perovskite semiconductors, one or more dopants of the same or opposite doping type are used, and their dosage is precisely controlled to achieve precise control of the conductivity type, resistivity, conductivity, carrier concentration, carrier mobility, Fermi level, energy band position, and photoelectric properties of the perovskite semiconductor.

3. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, wherein: The A' is an organic cation; A is a monovalent cation, such as cesium ion, methylamine ion, methylamine ion, ethylamine ion, hydrazine ion, guanidine ion, isopropylamine ion, imidazolium ion; B is a metal cation, including lead ion, tin ion, germanium ion; X is an anion including chloride ion, bromide ion, iodide ion; D includes but is not limited to organic polymer materials, organic small molecule materials, organic salts, inorganic salts, Lewis bases and Lewis acids.

4. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, wherein: The perovskite semiconductor doping method is as follows: dissolving one or more A'X, one or more AX, one or more BX and a dopant in a solvent to obtain a perovskite precursor solution, and preparing a doped perovskite material by a solution method; dissolving one or more A'X, one or more AX, and one or more BX in a solvent to obtain a perovskite precursor solution and preparing a perovskite material, and introducing the dopant into the perovskite through anti-solvent treatment, surface modification, solution fumigation, solid-state diffusion, plasma injection, etc., to obtain a doped perovskite semiconductor material; preparing a perovskite semiconductor material by a non-solution method using one or more A'X, one or more AX, and one or more BX, and introducing the dopant into the perovskite through anti-solvent treatment, surface modification, solution fumigation, solid-state diffusion, and plasma injection, to obtain a doped perovskite semiconductor material.

5. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, wherein: The physical forms of the perovskite semiconductors include polycrystalline thin films, single crystals, nanocrystals, quantum dots, nanowires, nanosheets, and mixed materials of the above perovskite materials with one or more of organic small molecules, polymers, metal oxides, III-V semiconductors, II-VI semiconductors, metals, inorganic dielectrics, and nanomaterials.

6. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, wherein: The dopant includes (2-(9H-carbazole-9-yl)ethyl)phosphonic acid, 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dibromo-9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, 3-(carbazole-9-yl)propionic acid, potassium bromide, sodium bromide, rubidium bromide , europium bromide; common functional groups containing lone pairs of electrons in the organic dopant molecules and common functional groups in Lewis bases include but are not limited to: phosphoric acid group, phosphoryl chloride group, phosphoryl group, organic phosphate group, sulfonic acid group, thiol group, amino group, hydroxyl group, cyano group, aldehyde group, carboxyl group, ketone group, and nitrogen nitrile group; common functional groups containing empty electron orbits and common functional groups in Lewis acids in the organic dopant molecules include but are not limited to: carbon-carbon double bond group, carbon-carbon triple bond group, and boric acid; common ions in the inorganic dopant molecules include but are not limited to: one of sodium ion, potassium ion, rubidium ion, europium ion, strontium ion, silver ion, indium ion, and bismuth ion, or a mixture in any proportion.

7. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, characterized in that: The one or more perovskite semiconductors that are doped to achieve p-type, n-type, and i-type conductivity form a homojunction or heterojunction; the one or more perovskite semiconductor materials forming the above homojunction are similar in overall composition and have the same band gap; the one or more perovskite semiconductor materials forming the above heterojunction have significantly different overall compositions, generally have different band gaps, and may also have the same band gap under special circumstances; the above homojunctions and heterojunctions are used to construct electronic or optoelectronic devices, including but not limited to diodes, transistors, solar cells, detectors, scintillators, light-emitting diodes, and semiconductor lasers.

8. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, characterized in that: Its carrier concentration reaches 10 20 cm -3 Above; its carrier mobility reaches 1000cm 2 V -1 s -1 Above; its fluorescence quantum yield reaches more than 95%.

9. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 1, characterized in that: When the hole concentration in p-type perovskite semiconductor reaches 10 18 cm -3 When the electron concentration in the n-type perovskite semiconductor reaches 10 18 cm -3 The above can also be called "heavily doped n-type perovskite semiconductor" or "n+ type perovskite semiconductor".

10. The perovskite semiconductor capable of achieving p-type, n-type, and i-type conductivity by doping according to claim 7, characterized in that: The optoelectronic device prepared by the homojunction or heterojunction is composed of a doped perovskite material and one or more of a substrate, an anode, an electron transport material, a hole transport material, and a cathode; the doped perovskite semiconductor can get rid of the dependence on the electron transport layer or the hole transport layer, realizing a perovskite optoelectronic device without a transport layer.

Images