阅读说明：本技术 一种原位连续调节钙钛矿材料及其制备方法 (In-situ continuous adjustment perovskite material and preparation method thereof ) 是由 徐春祥 张振华 石增良 于 2020-12-18 设计创作，主要内容包括：本发明公开了一种原位连续调节钙钛矿材料,分子式为APbE-(3-x)F-x,A为MA或Cs,E、F选自Cl、Br、I中不同的两种,x＝aln(t+t-0)+c,其中,0≤x≤3,t为反应时间,a、c、t-0为修正参数。本发明还公开了一种简易可控、成本低廉的调控的原位连续调节钙钛矿材料的制备方法,包括以下步骤：步骤一,制备钙钛矿前驱体；步骤二、将溴源或氯源或碘源固体粉末的石英舟放置在石英管中间,将前驱体钙钛矿放在石英管的炉塞口处；步骤三,向石英管通入保护气体排气；步骤四,将石英管加热到60～400℃,冷却至室温。本发明采用气相/固相阴离子交换方法,原材料成本低廉,并且该方法操作简易、可控程度高,工艺简单。(The invention discloses an in-situ continuously-regulated perovskite material with a molecular formula of APbE 3‑x F x A is MA or Cs, E, F is selected from Cl, Br and I, x is aln (t + t) 0 ) + c, where x is not less than 0 and not more than 3, t is reaction time, a, c, t 0 To correct the parameters. The invention also discloses a preparation method of the simple, controllable and low-cost regulated in-situ continuous adjustment perovskite material, which comprises the following steps: step one, preparing a perovskite precursor; secondly, placing a quartz boat of bromine source or chlorine source or iodine source solid powder in the middle of a quartz tube, and placing the quartz boat in the middle of the quartz tubeThe precursor perovskite is placed at a furnace plug port of the quartz tube; introducing protective gas into the quartz tube for exhausting; and step four, heating the quartz tube to 60-400 ℃, and cooling to room temperature. The invention adopts a gas phase/solid phase anion exchange method, the cost of raw materials is low, and the method has the advantages of simple operation, high controllable degree and simple process.)

1. An in-situ continuously regulated perovskite material, characterized in that: molecular formula of APbE_3-xF_xA is MA or Cs, E, F is selected from Cl, Br and I, x is aln (t + t)₀) + c, where x is not less than 0 and not more than 3, t is reaction time, a, c, t₀To correct the parameters.

2. The method according to claim 1, wherein the method comprises the following steps:

step one, preparing a perovskite precursor MAPbCl₃、MAPbBr₃、MAPbI₃、CsPbCl₃、CsPbBr₃Or CsPbI₃；

Secondly, placing a quartz boat of bromine source or chlorine source or iodine source solid powder in the middle of a quartz tube of the CVD tube furnace, and placing the precursor perovskite prepared in the first step at a furnace plug of the quartz tube;

introducing protective gas into the quartz tube at a flow rate of 1-300 sccm, and performing exhaust treatment for 1-60 min, wherein the gas pressure is maintained at 0-1000000 Pa in the reaction process;

and step four, heating the quartz tube to 60-400 ℃, and cooling to room temperature.

3. The method according to claim 2, wherein the perovskite material is prepared by in-situ continuous adjustment, and the method comprises the following steps: in the second step, the bromine source is methyl amine bromide or cesium bromide.

4. The method according to claim 2, wherein the perovskite material is prepared by in-situ continuous adjustment, and the method comprises the following steps: in the second step, the chlorine source is methyl ammonium chloride or cesium chloride.

5. The method according to claim 2, wherein the perovskite material is prepared by in-situ continuous adjustment, and the method comprises the following steps: in the second step, the iodine source is methyl ammonium iodide or cesium iodide.

6. The method according to claim 2, wherein the perovskite material is prepared by in-situ continuous adjustment, and the method comprises the following steps: in the third step, the protective gas is nitrogen, argon, helium, neon, krypton, xenon or hydrogen.

7. The method according to claim 2, wherein the perovskite material is prepared by in-situ continuous adjustment, and the method comprises the following steps: in the fourth step, the heating rate is 0.01-100 ℃/s, and the heat preservation time is 0-10000 min.

8. The method according to claim 2, wherein the perovskite material is prepared by in-situ continuous adjustment, and the method comprises the following steps: in the fourth step, the cooling rate is 0-1000 ℃/s.

Technical Field

The invention relates to a perovskite material and a preparation method thereof, in particular to an in-situ continuously-adjusted perovskite material and a preparation method thereof.

Background

Perovskite has become one of the most interesting materials in the world through development of its excellent optical and electrical properties for a short period of time. The chemical structural formula of the perovskite is ABX₃Where a is typically a monovalent cation, B is a divalent metal ion, and X is a halide, the perovskite material thus has a wide variety of components and its properties vary accordingly.

The chinese patent with application number 201710764812.7 discloses a preparation method of cesium lead bromine inorganic perovskite thin film, but has the following disadvantages: the required bromine gas is a highly toxic pollution gas, is extremely unfavorable in the aspects of biological safety or environmental protection, and cannot continuously and controllably regulate the components and the performance of the perovskite material in situ. The chinese patent with application number 201811397013.1 discloses a preparation method of halogen-like perovskite quantum dot material, but has the following disadvantages: it also fails to provide in situ continuous, controlled adjustment of the perovskite material's composition and properties.

In general, current research on adjusting the composition of perovskite materials mainly utilizes a spin coating method to prepare single-component perovskite thin films with specific halogen ratios. However, the method has the defects of stoichiometric error and the like, and more importantly, the components and the performance of the film formed by the method cannot be continuously and stably regulated in situ, and the prepared perovskite material cannot meet the actual requirement.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention aims to provide an in-situ continuously-adjusted perovskite material with high controllability, and the invention also aims to provide a simple, controllable and low-cost preparation method of the in-situ continuously-adjusted perovskite material.

The technical scheme is as follows: the perovskite material with the molecular formula of APbE is continuously adjusted in situ_3-xF_xA is MA or Cs, E, F is selected from Cl, Br and I, x is aln (t + t)₀) + c, where x is not less than 0 and not more than 3, t is reaction time, a, c, t₀And fitting the experimental value of the element content according to the relation of the component and the time change to determine a parameter value for correcting the parameter.

The preparation method of the in-situ continuously-adjusted perovskite material comprises the following steps:

step one, perovskite precursors MAPbCl with different morphologies are prepared by using a spin-coating method, an evaporation method, a recrystallization method and a CVD growth method₃、MAPbBr₃、MAPbI₃、CsPbCl₃、CsPbBr₃Or CsPbI₃；

Secondly, placing a quartz boat of bromine source or chlorine source or iodine source solid powder in the middle of a quartz tube of the CVD tube furnace, and placing the precursor perovskite prepared in the first step at a furnace plug of the quartz tube;

introducing protective gas into the quartz tube at a flow rate of 1-300 sccm, and performing exhaust treatment for 1-60 min, wherein the gas pressure is maintained at 0-1000000 Pa in the reaction process;

and step four, heating the quartz tube to 60-400 ℃, and cooling to room temperature.

Further, in the first step, the perovskite precursors with different morphologies are nanoparticles, nanocrystals, nanorods, nanowires, microwires, nanoblocks, microblocks, nanospheres, microspheres and films.

Further, in step two, the bromine source is methyl amine bromide (MABr) or cesium bromide (CsBr). The chlorine source is methyl ammonium chloride (MACl) or cesium chloride (CsCl). The iodine source is Methyl Ammonium Iodide (MAI) or cesium iodide (CsI).

Further, in the third step, the protective gas is nitrogen, argon, helium, neon, krypton, xenon, or hydrogen.

Further, in the fourth step, the temperature rise rate is 0.01-100 ℃/s, and the heat preservation time is 0-1000 min. The cooling rate is 0-100 ℃/s.

The reaction principle is as follows: because the reaction is carried out at a lower temperature, the slow evaporation of the low-quality bromine source or chlorine source or iodine source solid powder can be controlled, so that the concentration of a reactant carrying out anion exchange reaction with perovskite precursors with different shapes is lower, and the components of the perovskite precursors are continuously and controllably adjusted in a smooth state.

Has the advantages that: compared with the prior art, the invention has the following remarkable characteristics: the method adopts a gas phase/solid phase anion exchange method, has low raw material cost, does not need a complex and expensive reaction device, is simple and easy to operate, has high controllable degree and simple process, has obvious effect on in-situ continuous regulation and control of the components and band gap of the perovskite material, and has high regulation and control accuracy.

Drawings

FIG. 1 is a phase diagram of the X-ray diffraction pattern of the material obtained in example 1 of the present invention;

FIG. 2 is a SEM image of the material obtained in example 1 of the present invention;

FIG. 3 is a graph showing an ultraviolet-visible absorption spectrum of a material obtained in example 1 of the present invention;

FIG. 4 shows photoluminescence of a material obtained in example 1 of the present invention;

FIG. 5 is a graph of the composition versus time of an EDS elemental analysis characterization of the material obtained in example 1 of the present invention.

Detailed Description

The raw materials used in the following examples were purchased and used as received.

PbI₂、PbBr₂、PbCl₂(purity: 99%, manufacturer: Allatin); hydrochloric acid (purity: AR, manufacturer: Chinese medicine); dimethylformamide (purity: 99.5%, anhydrous manufacturer: Chinese medicine); MAI, MABr, MACl, CsI, CsBr, CsCl (purity: 99%, manufacturer: Saibarote).

In the following examples, the substrate cleaning steps were: the method comprises the following steps of washing the surface of a glass or other kinds of substrates by using a detergent and a test tube brush to remove stains such as oil stains possibly on the surface, washing the substrate by using ultrapure water for a plurality of times, then carrying out ultrasonic cleaning treatment on the substrate by using ultrapure water, acetone and ethanol in sequence for 10min each by using an ultrasonic cleaner, blow-drying the substrate by using nitrogen gas to fully dry, and finally carrying out hydrophilic treatment on the substrate (for example, soaking by using a piranha solution, treating by using a plasma cleaner and the like).

Spin coating processPreparation of precursor perovskite MAPbI₃A film comprising the steps of:

s1: 1mol of PbI₂The solution was sonicated in a mixture of 975. mu.L of DMF and 25. mu.L of HCl. The solution was then centrifuged at 6000rpm for 5min to obtain a supernatant. Then, about 50. mu.L of the supernatant was dropped onto the substrate, and after soaking for 30 seconds, the resultant was treated by spin coating at 3000rpm for 20 seconds using a spin coater to prepare a thin film. The film was then placed in an oven at 60 ℃ for 10min and finally annealed in an oven at 200 ℃ for 40min in air. After the temperature is returned to room temperature, PbI is obtained₂A film;

s2: the quartz boat containing 300mg of MAI solid powder was placed in the middle of the CVD tube furnace quartz tube, and the prepared PbI was introduced₂The membrane was placed downstream (furnace stopper) of the quartz tube. Then, nitrogen gas is continuously introduced into the quartz tube at a flow rate of 30sccm to perform exhaust treatment for 20min, and a vacuum pump is used to pump the gas in the quartz tube and maintain the pressure inside the quartz tube within 50Pa in the whole reaction process. Then, the CVD tube furnace was heated to 110 ℃ at a heating rate of 10 ℃/min, and the reaction treatment was maintained at that temperature for 2 hours. After the heating process is completed and the temperature is reduced to room temperature, the precursor perovskite MAPbI is obtained₃A film.

When MAPbCl is prepared by using a spin coating method₃、MAPbBr₃、CsPbI₃、CsPbBr₃Or CsPbCl₃When the perovskite thin film is used as a precursor, the raw materials are replaced, and the operation is still carried out according to the steps.

The invention is further described with reference to the following figures and detailed description, without limiting its scope.

Example 1

In-situ continuous adjustment perovskite material MAPbI_3-xBr_xA method of composition and performance comprising the steps of:

step one, preparing precursor perovskite MAPbI by using spin coating method₃A film;

secondly, placing a quartz boat of 100mg of MABr solid powder in the middle of a quartz tube of a CVD tube furnace, and placing the precursor perovskite prepared in the first step at the downstream (furnace plug opening) of the quartz tube;

introducing protective gas nitrogen into the quartz tube at the flow rate of 30sccm, exhausting for 20min, and maintaining the gas pressure at about 50Pa in the reaction process;

and step four, heating the quartz tube to 105 ℃ at a heating rate of 10 ℃/min, reacting at the temperature for 0-180 min (specifically, 0min, 15min, 30min, 45min, 60min, 90min, 120min, 150min and 180min respectively), and cooling to room temperature at a cooling rate of 2 ℃/s.

Wherein, the precursor perovskite MAPbI of the first step₃The film can be replaced by any one of nanocrystalline, nano-rods, micro-rods, nano-wires, micro-wires, nano-blocks, micro-blocks, nano-spheres, micro-spheres, nano-sheets and micro-sheets. And the nitrogen in the third step can be replaced by any one of argon, helium, neon, krypton, xenon and hydrogen.

And respectively characterizing products obtained in different reaction times, as shown in figures 1-4. As can be seen from FIG. 1, the in-situ continuous control of the perovskite composition is possible by this method. As can be seen from FIG. 2, the perovskite component can be well controlled by the method, and the morphology of the sample can be well maintained. As can be seen from FIG. 3, the method can continuously regulate and control the band gap performance of the perovskite in situ. As can be seen from FIG. 4, the method enables continuous in-situ control of the optical properties of the perovskite. It can be seen from fig. 5 that the composition varies logarithmically with time.

Fitting the data according to FIG. 5 to obtain the molecular formula MAPbI_3-xBr_xThe relationship to the reaction time t is:

x＝aln(t+t₀)+c

wherein x is more than or equal to 0 and less than or equal to 3, a, c and t₀To correct the parameters, a-0.48317, c-0.34843, t₀＝0.48654。

Example 2

In-situ continuous adjustment perovskite material MAPbBr_3-xCl_xThe preparation method comprises the following steps:

step one, preparing precursor perovskite MAPbBr by using spin coating method₃A film;

step two, placing a quartz boat of 50mg MACl solid powder in the middle of a quartz tube of a CVD tube furnace, and placing the precursor perovskite prepared in the step one at the downstream (furnace plug port) of the quartz tube;

introducing protective gas argon into the quartz tube at the flow rate of 30sccm, exhausting for 20min, and maintaining the gas pressure at about 50Pa in the reaction process;

and step four, heating the quartz tube to 105 ℃ at the heating rate of 5 ℃/min, reacting at the temperature for 0-10000 min (specifically, 0min, 1000min, 2000min, 3000min, 4000min, 5000min, 6000min, 7000min, 8000min, 9000min and 10000min respectively), and cooling to room temperature at the natural cooling rate.

Wherein, the precursor perovskite MAPbBr in the first step₃The film can be replaced by any one of nanocrystalline, nano-rods, micro-rods, nano-wires, micro-wires, nano-blocks, micro-blocks, nano-spheres, micro-spheres, nano-sheets and micro-sheets. And the argon in the step three can be replaced by any one of nitrogen, helium, neon, krypton, xenon and hydrogen.

The products obtained at different reaction times were characterized and fitted as in example 1 to obtain the molecular formula MAPbBr_3-xCl_xThe relationship to the reaction time t is:

x＝aln(t+t₀)+c

wherein x is more than or equal to 0 and less than or equal to 3, a, c and t₀For correcting the parameters, fitting determination is performed on the experimental data.

Example 3

In-situ continuous regulation perovskite material MAPbCl_3-xI_xThe preparation method comprises the following steps:

step one, preparing a precursor perovskite MAPbCl by using a recrystallization method₃A nanowire;

secondly, placing a quartz boat of 120mg of MAI solid powder in the middle of a quartz tube of the CVD tube furnace, and placing the precursor perovskite prepared in the first step at the downstream (furnace plug port) of the quartz tube;

introducing protective gas helium into the quartz tube at the flow rate of 1sccm, exhausting for 20min, and maintaining the gas pressure at about 0Pa in the reaction process;

and step four, heating the quartz tube to 60 ℃ at the heating rate of 100 ℃/min, reacting for 0-500 min (specifically, 0min, 50min, 100min, 150min, 200min, 250min, 300min, 350min, 400min, 450min and 500min respectively) at the temperature, and cooling to room temperature at the cooling rate of 1000 ℃/s.

Wherein, the precursor perovskite MAPbCl of the step one₃The nano-wire can be replaced by any one of nanocrystalline, nano-rod, micro-wire, nano-block, micro-block, nano-sphere, micro-sphere, nano-sheet and micro-sheet. Helium in the third step can be replaced by any one of nitrogen, argon, neon, krypton, xenon and hydrogen.

The products obtained at different reaction times were characterized and fitted as in example 1 to obtain the molecular formula MAPbCl_3-xI_xThe relationship to the reaction time t is:

x＝aln(t+t₀)+c

wherein x is more than or equal to 0 and less than or equal to 3, a, c and t₀For correcting the parameters, fitting determination is performed on the experimental data.

Example 4

In-situ continuous adjustment perovskite material CsPbI_3-xBr_xThe preparation method comprises the following steps:

step one, preparing precursor perovskite CsPbI by using recrystallization method₃A nanorod;

secondly, placing a quartz boat of 100mg of MABr solid powder in the middle of a quartz tube of a CVD tube furnace, and placing the precursor perovskite prepared in the first step at the downstream (furnace plug opening) of the quartz tube;

introducing protective gas helium into the quartz tube at the flow rate of 30sccm, exhausting for 20min, and maintaining the gas pressure at about 50Pa in the reaction process;

and step four, heating the quartz tube to 105 ℃ at the heating rate of 50 ℃/s, reacting for 0-200 min (specifically, 0min, 20min, 40min, 60min, 80min, 100min, 120min, 140min, 160min, 180min and 200min respectively) at the temperature, and cooling to room temperature at the cooling rate of 50 ℃/s.

Wherein, the precursor CsPbI of the first step₃The nano rod can be replaced by any one of nano rod, micro rod, nano wire, micro wire, nano block, micro block, nano ball, micro ball, nano sheet and micro sheet. Helium in the third step can be replaced by any one of nitrogen, argon, neon, krypton, xenon and hydrogen.

The products obtained at different reaction times were characterized and fitted as in example 1 to obtain the molecular formula CsPbI_3-xBr_xThe relationship to the reaction time t is:

x＝aln(t+t₀)+c

wherein x is more than or equal to 0 and less than or equal to 3, a, c and t₀For correcting the parameters, fitting determination is performed on the experimental data.

Example 5

In-situ continuous adjustment perovskite material CsPbBr_3-xCl_xThe preparation method comprises the following steps:

step one, preparing precursor CsPbBr by using CVD growth method₃Micro-balls;

step two, placing a quartz boat of 180mg CsCl solid powder in the middle of a quartz tube of a CVD tube furnace, and placing the precursor perovskite prepared in the step one at the downstream (furnace plug port) of the quartz tube;

introducing protective gas krypton into the quartz tube at the flow rate of 300sccm, and exhausting for 20min, wherein the gas pressure is maintained at about 1000000Pa in the reaction process;

and step four, heating the quartz tube to 400 ℃ at the heating rate of 30 ℃/s, reacting at the temperature for 0-800 min (specifically, 0min, 100min, 200min, 300min, 400min, 500min, 600min, 700min and 800min respectively), and cooling to room temperature at the cooling rate of 20 ℃/s.

Wherein, the precursor CsPbBr in the first step₃The micro-ball canAnd replacing the nano-crystal, nano-rod, micro-rod, nano-wire, micro-wire, nano-block, micro-block, nano-sheet and micro-sheet with any one of nano-crystal, nano-rod, micro-rod, nano-wire, micro-wire, nano-block, micro-block, nano-sheet and micro-sheet. Helium in the third step can be replaced by any one of nitrogen, argon, neon, krypton, xenon and hydrogen.

The products obtained at different reaction times were characterized and fitted as in example 1 to obtain the molecular formula CsPbBr_3-xCl_xThe relationship to the reaction time t is:

x＝aln(t+t₀)+c

wherein x is more than or equal to 0 and less than or equal to 3, a, c and t₀For correcting the parameters, fitting determination is performed on the experimental data.

Example 6

In-situ continuous adjustment perovskite material CsPbCl_3-xI_xThe preparation method comprises the following steps:

step one, preparing precursor perovskite CsPbCl by using CVD growth method₃A film.

Step two, placing a quartz boat of 160mg CsI solid powder in the middle of a quartz tube of a CVD tube furnace, and placing the precursor perovskite prepared in the step one at the downstream (furnace plug port) of the quartz tube;

introducing protective gas argon into the quartz tube at the flow rate of 150sccm, exhausting for 20min, and maintaining the gas pressure at about 5000Pa in the reaction process;

and step four, heating the quartz tube to 230 ℃ at a heating rate of 70 ℃/min, reacting at the temperature for 0-400 min (specifically, 0min, 50min, 100min, 150min, 200min, 250min, 300min, 350min and 400min respectively), and cooling to room temperature at a cooling rate of 80 ℃/s.

Wherein the precursor CsPbCl of the first step₃The film can be replaced by any one of nanocrystalline, nano-rods, micro-rods, nano-wires, micro-wires, nano-blocks, micro-blocks, nano-spheres, micro-spheres, nano-sheets and micro-sheets. And the helium and argon in the step three can be replaced by any one of nitrogen, helium, neon, krypton, xenon and hydrogen.

According to the examples1, respectively characterizing products obtained at different reaction times, and fitting to obtain the molecular formula CsPbCl_3-xI_xThe relationship to the reaction time t is:

x＝aln(t+t₀)+c

wherein x is more than or equal to 0 and less than or equal to 3, a, c and t₀For correcting the parameters, fitting determination is performed on the experimental data.