CN113279062B - Nickel-doped lead titanate single crystal film and preparation and application thereof - Google Patents

Nickel-doped lead titanate single crystal film and preparation and application thereof Download PDF

Info

Publication number
CN113279062B
CN113279062B CN202110532409.8A CN202110532409A CN113279062B CN 113279062 B CN113279062 B CN 113279062B CN 202110532409 A CN202110532409 A CN 202110532409A CN 113279062 B CN113279062 B CN 113279062B
Authority
CN
China
Prior art keywords
nickel
single crystal
film
doped
reaction kettle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110532409.8A
Other languages
Chinese (zh)
Other versions
CN113279062A (en
Inventor
任召辉
陈嘉璐
林宸
杨倩
韩高荣
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhejiang University ZJU
Original Assignee
Zhejiang University ZJU
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhejiang University ZJU filed Critical Zhejiang University ZJU
Priority to CN202110532409.8A priority Critical patent/CN113279062B/en
Publication of CN113279062A publication Critical patent/CN113279062A/en
Application granted granted Critical
Publication of CN113279062B publication Critical patent/CN113279062B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/22—Complex oxides
    • C30B29/32—Titanates; Germanates; Molybdates; Tungstates
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
    • C30B29/64—Flat crystals, e.g. plates, strips or discs
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
    • C30B7/10—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions by application of pressure, e.g. hydrothermal processes

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

The invention discloses a nickel-doped lead titanate single crystal film and preparation and application thereof. The film is a nickel-doped lead titanate monocrystal film with a smooth and flat surface, a flat interface and a thickness of 200 nm-3000 nm. The nickel-doped lead titanate single crystal film is prepared by taking tetra-n-butyl titanate, lead nitrate and nickel nitrate hexahydrate as main raw materials, taking potassium hydroxide as a mineralizer, introducing a coprecipitation method, taking niobium-doped strontium titanate as a substrate, and carrying out hydrothermal reaction at 200-220 ℃. The large-area hetero-epitaxial film with a smooth and flat surface prepared by the invention has wide potential application prospect in the fields of ferroelectric memories, pyroelectric sensors, optical waveguides, optical detection, electro-optical switches and the like. The method has the advantages of simple process, easy control, low cost and easy large-scale production.

Description

Nickel-doped lead titanate single crystal film and preparation and application thereof
Technical Field
The invention belongs to the field of inorganic non-metal ferroelectric materials and preparation, and particularly relates to growth of a single crystal film.
Background
The ferroelectric material has a large application market due to the characteristics of good ferroelectric property, high dielectric constant, high stability and the like. Lead titanate is a typical ferroelectric material, has a tetragonal perovskite structure, has properties of a curie temperature of up to 490 ℃, good stability, large piezoelectric anisotropy and the like, and has a limitation in application because the energy band gap (Eg) of the lead titanate is larger than 3 eV. Doping modification is one of effective means for improving the photovoltaic performance of the material. The introduction of the dopant can directly change the energy band gap of the ferroelectric oxide, thereby changing the wavelength range of the light absorbed by the material and improving the performance in the visible light photovoltaic field.
Bennett et al, entitled "New Highly Polar Semiconductor Ferroelectrics through d8 Cation-O Vacancy Substitution into PbTiO3Article of A thermal Study "(Journal of the American Chemical society.130,2008, 17)409-17412), the effect of transition metal (Ni, Fe, Mn, Pt, etc.) doping on lead titanate is disclosed, where: ni is a transition metal element, close to the filled and empty d-orbitals in energy, and2+with Ti4+The ionic radii are close, the ionic radii are calculated through a first principle, and the Ni-doped lead titanate is adopted, so that the energy band structure can be effectively adjusted, the asymmetry inside the material is increased, and the generation of photovoltaic displacement current is facilitated. But the study is only limited to theoretical calculations.
In addition, as thin film materials are easy to integrate, the size of the manufactured devices is small, and the breakdown voltage is high, with the continuous development of technologies of miniaturized large-scale integrated circuits, research centers of people in recent years have shifted from bulk materials to thin film materials. The ferroelectric film with the thickness of tens of nanometers to several micrometers has the characteristics of good ferroelectricity, piezoelectricity, pyroelectric property, electrooptic and nonlinear optics and the like, can be widely applied to the fields of microelectronics, optoelectronics, integrated optics, micro-electro-mechanical systems and the like, and is one of the leading edges and hot spots of the current high and new technology research. In order to fully exert the properties of the ferroelectric thin film, it is desirable that the ferroelectric thin film be a single crystal or a polycrystalline structure in which crystal grains are preferentially oriented. For single crystal thin film materials, a smooth, flat surface is one of the requirements for high performance. However, the doping generally increases the disorder degree of the system, breaks the balance environment of the original reaction, and is easy to cause component segregation, so that when a doped modified film is epitaxially grown, particle aggregation is easy to form on a substrate or the fractal phenomenon of the film occurs; further, the higher the doping ratio, the more difficult the formation of the single crystal thin film material, and the more difficult the formation of the single crystal thin film material having a smooth flat surface.
Therefore, the current research on Ni-doped lead titanate films generally stays at the polycrystalline film stage, and the preparation methods are a solid phase method and a sol-gel method. As reported by scholars on Ceramics International in 2017 (C.W.ZHao et al Ceramics International,43,2017, 7861-): the Ni-doped lead titanate polycrystalline film prepared by the sol-gel method has higher photovoltaic current than that before doping, but due to the defects of grain boundaries, uneven grain sizes and the like existing in the polycrystalline film, the influence of Ni element on the photovoltaic performance of lead titanate cannot be researched reasonably, and the magnitude of the photovoltaic current and the response rate of materials cannot be improved.
The traditional preparation methods of the single crystal thin film materials, such as pulsed laser deposition, chemical vapor deposition and the like, although the preparation requirements of the lead titanate single crystal can be met, the operation is complex, the price is high, especially uniform high-quality doping is difficult to realize, and the method cannot be used for preparing the doped lead titanate single crystal thin film; moreover, the thickness of the film grown by the preparation methods is only dozens of nanometers because of the lower material diffusion capacity of the gas phase method, and a thicker film cannot be formed at a higher growth rate; in addition, the reaction temperature of the pulse laser deposition method is higher than the curie temperature of the Ni-doped lead titanate, and the phase transition process from the paraelectric phase to the ferroelectric phase is inevitably carried out in the process of cooling to room temperature in the preparation process, which may introduce defects into the thin film, affect the microstructure and the performance, and make the structure and the performance of the thin film difficult to control.
Disclosure of Invention
In view of the above, the present invention aims to provide a nickel-doped lead titanate single crystal thin film, and a preparation method and an application thereof, wherein the nickel-doped lead titanate single crystal thin film has a smooth and flat surface, a high quality (atomically flat) interface, a thickness of a micron order, and excellent photovoltaic performance. The preparation method is simple, the process is easy to operate, the raw materials are simple and easy to obtain, the problem that the nickel-doped lead titanate single crystal thin film is difficult to grow is solved, the problem that a thick film (especially a high-quality thick film) is difficult to grow in the conventional single crystal thin film preparation technology is effectively solved, and the processing and the manufacturing of devices are convenient.
In order to achieve the purpose, the invention provides a nickel-doped lead titanate monocrystal film which has a flat surface and a flat interface, and the thickness of the film is 200 nm-3000 nm.
In a preferred technical scheme, the doping amount of the nickel is 1-10 mol%, and the doping amount of the nickel refers to the mol percentage of nickel element in the sum of titanium and nickel element, and the unit is expressed as mol%.
Meanwhile, the invention also provides a preparation method of the nickel-doped lead titanate single crystal film, which comprises the following steps:
(1) adding potassium hydroxide into an inner container of a reaction kettle, adding deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 3.9-7.8 mol/L;
(2) Dissolving nickel nitrate hexahydrate in ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate is completely dissolved; then adding tetra-n-butyl titanate into the mixture, and stirring for 2-30 min; adding lead nitrate into the mixed solution, and fully stirring the mixture until the lead nitrate is completely dissolved to obtain a mixed solution; the molar ratio of the sum of Ti and Ni elements to Pb element is 1: (1.1-1.5); the nickel element accounts for 1 to 10 mol% of the sum of the titanium element and the nickel element;
(3) dropwise adding the mixed solution prepared in the step (2) into excessive ammonia water, standing for 0.5-3 h after dropwise adding is finished, and filtering to obtain flocculent precipitate;
(4) adding the flocculent precipitate obtained in the step (3) into the potassium hydroxide aqueous solution obtained in the step (1), adding deionized water into the flocculent precipitate to enable the final volume to reach 80-90% of the volume of the inner container of the reaction kettle, and stirring for 2-3 h to disperse the precipitate to obtain a precursor suspension; in the precursor suspension, the molar ratio of the sum of Ti and Ni elements to K element is 1: (10-100);
(5) placing the strontium niobate-doped titanate single crystal substrate into a precursor suspension, placing a reaction kettle liner filled with the precursor suspension into a reaction kettle, sealing, and keeping at 200-220 ℃ for 6-24 hours to perform hydrothermal reaction; then, the reaction kettle is naturally cooled to room temperature; and after the kettle is unloaded, washing the reaction product, filtering and drying to obtain the nickel-doped lead titanate single crystal film.
In the preferable technical scheme, in the step (2), in the solution formed by dissolving nickel nitrate hexahydrate in ethylene glycol monomethyl ether, the molar concentration of nickel nitrate hexahydrate is 0.001-0.015 mol/L, and preferably 0.002-0.012 mol/L.
In a preferred technical scheme, in the step (2), the molar ratio of the sum of the Ti and Ni elements to the Pb element is 1: (1.1-1.25).
In the preferable technical scheme, in the step (2), after the lead nitrate is added, the stirring time is 30-60 min.
In the present invention, in the step (3), the excess of ammonia water means excess over the precipitated cation (Ni)2+、Ti4+And Pb2+) When the amount of the stoichiometric amount of aqueous ammonia, for example, 10 times or more the total amount of Ti and Ni elements is required, the amount of aqueous ammonia is excessive. In the present invention, the excess amount of aqueous ammonia means that the molar ratio of the sum of Ti and Ni elements to aqueous ammonia is preferably 1: (100 to 700), more preferably 1: (200-600), most preferably 1: (240-500).
In the preferred technical solution, in the step (5), the orientation of the strontium niobate-doped titanate single crystal in the strontium niobate-doped titanate single crystal substrate is <100>, so that the (001) crystal plane exposed by the substrate is matched with the (001) crystal plane of the nickel-doped lead titanate, and the direction of the epitaxial growth of the nickel-doped lead titanate film is ensured to be the <001> direction.
In a preferred technical scheme, in the step (5), the size of the niobium-doped strontium titanate single crystal substrate is 10mm × 5mm × 0.5 mm.
In a preferred technical scheme, in the step (5), the niobium-doped strontium titanate single crystal substrate is cleaned before use, and the cleaning step comprises: and cleaning the niobium-doped strontium titanate single crystal substrate by using acetone, ethanol and deionized water in sequence.
In a preferred technical scheme, in the step (5), the niobium-doped strontium titanate single crystal substrate is fixed on a polytetrafluoroethylene support and is placed into the precursor suspension together.
In a preferred technical scheme, in the step (5), the reaction kettle is a reaction kettle with a polytetrafluoroethylene inner container and a stainless steel sleeve which is closed. The polytetrafluoroethylene inner container has good high-temperature resistance and pressure resistance, and the stainless steel sealed reaction kettle is sleeved outside the inner container and used for ensuring that the inner container does not deform in the reaction, thereby maintaining a high-pressure environment.
In a preferred technical scheme, in the step (5), the washing process of the reaction product is as follows: the reaction product was repeatedly washed with deionized water and anhydrous ethanol.
Meanwhile, the invention also provides application of the nickel-doped lead titanate single crystal film. The nickel-doped lead titanate single crystal film has excellent photovoltaic performance by testing: the short-circuit current is strong and is in direct proportion to the light intensity, and the photoelectric detector can be used as a passive photoelectric detector and applied to the fields of ferroelectric memories, pyroelectric sensors, optical waveguides, optical detection, electro-optical switches and the like.
In the invention, the purities of the tetra-n-butyl titanate, the lead nitrate, the nickel nitrate hexahydrate and the ethylene glycol monomethyl ether are not lower than the chemical purities: by mass percent, tetra-n-butyl titanate: not less than 98.0%, lead nitrate: not less than 99.0%, nickel nitrate hexahydrate: not less than 98.0%, ethylene glycol monomethyl ether: not less than 99.5 percent. Potassium hydroxide: not less than 85.0 percent. The mass percentage concentration of the ammonia water is 25-28%.
In the present invention, the room temperature may be 0 to 40 ℃, preferably 20 to 25 ℃.
According to the method, nickel nitrate hexahydrate is used as a nickel source, tetrabutyl titanate is used as a titanium source, lead nitrate is used as a lead source, ethylene glycol monomethyl ether is used as an organic solvent, ammonia water is used as a precipitator, the nickel source, the titanium source and the lead source are sequentially added into the organic solvent in a proper proportion to be mixed, and then coprecipitation is carried out in the ammonia water to form uniform nano particles, and meanwhile, the chemical components are kept uniform, the split particle size is small, and the distribution is uniform; then, potassium hydroxide with proper concentration is used as a mineralizer, niobium-doped strontium titanate single crystal is used as a substrate, hydrothermal reaction is carried out at high temperature, and high-quality nickel-doped lead titanate single crystal thin film is obtained through epitaxial growth. Therefore, the invention combines the coprecipitation method and the hydrothermal method, and prepares the high-quality nickel-doped lead titanate single crystal film with different doping concentrations by controlling specific preparation conditions, the film has a smooth and flat surface and an atomic-level flat interface, the thickness of the film can reach 3000nm, namely 3 mu m, the problem that a thick film is difficult to grow in the conventional single crystal film preparation technology is effectively solved, and the processing and the manufacturing of devices are convenient. Accordingly, since the prepared nickel-doped lead titanate single crystal thin film has a smooth and flat surface, a high-quality flat interface and a thickness of the order of micrometers, it also exhibits excellent photovoltaic properties: the short-circuit current is strong and is in direct proportion to the light intensity, the material requirement of the passive photoelectric detector is met, and the photoelectric detector has wide potential application prospect in the fields of ferroelectric memories, pyroelectric sensors, optical waveguides, optical detection, electro-optical switches and the like.
Compared with the prior art, the invention has the following beneficial technical effects:
(1) different from the nickel-doped lead titanate film polycrystalline film in the prior art, the nickel-doped lead titanate film is single crystal, so that the defects of uneven grain boundary and grain size in the film are avoided.
(2) Different from the low-quality nickel-doped lead titanate film in the prior art, the nickel-doped lead titanate single crystal film has a smooth and flat surface and a high-quality interface (PTO/NSTO forms an atomically flat interface), ensures excellent ferroelectric property and excellent photovoltaic property of the high-quality single crystal film, has strong short-circuit current, is in direct proportion to light intensity, meets the material requirement of a passive optical detector, and has wide potential application prospect in the fields of ferroelectric memories, pyroelectric sensors, optical waveguides, optical detection, electro-optical switches and the like.
(3) The nickel-doped lead titanate single crystal film has micron-sized thickness, which is sample thickness that can not be achieved by common single crystal film growing technologies (such as pulsed laser deposition, chemical vapor deposition and the like), effectively solves the problem that thick films are difficult to grow in the conventional single crystal film preparing technology, and is convenient for processing and manufacturing devices.
(4) The method is different from single hydrothermal synthesis and single coprecipitation reaction, creatively combines the coprecipitation reaction and the hydrothermal reaction, carefully selects a solvent and a precipitator according to the characteristics of reaction raw materials, reasonably adjusts the material adding sequence and reaction conditions in the coprecipitation reaction, and solves the problem of component segregation easily occurring in conventional doping, thereby avoiding the phenomenon of particle aggregation or film fractal on a substrate during the growth of the film, obtaining the nickel-doped lead titanate single crystal film with large area, high quality and micron-sized thickness, and being hopeful to be used as a high-performance photovoltaic material.
(5) The preparation method has the advantages of simple process, easy control, low cost and easy large-scale production, and can obtain large-area high-quality heteroepitaxial thin films with smooth surfaces.
Drawings
FIG. 1 is an X-ray diffraction (XRD) pattern of the thin film product obtained in example 1.
FIG. 2 is a Scanning Electron Microscope (SEM) picture of the surface topography of the film product made in example 1.
FIG. 3 is a Scanning Electron Microscope (SEM) picture of the sectional morphology of the film product obtained in example 1.
FIG. 4a is a photograph of a spherical aberration corrected field emission scanning transmission electron microscope (HAADF-STEM) at atomic resolution of the thin film product produced in example 1 at the interface.
FIG. 4b is a photograph of the product film from example 1 taken with a spherical aberration-corrected field emission scanning transmission electron microscope (HAADF-STEM) at an atomic resolution of 500nm from the interface.
FIG. 4c is a photograph of a spherical aberration corrected field emission scanning transmission electron microscope (HAADF-STEM) with atomic resolution at 1000nm from the interface of the thin film product made in example 1.
FIG. 5 is a film product obtained in example 1
Figure BDA0003068413420000061
And (6) sweeping the result.
Fig. 6 is a schematic diagram of a photovoltaic performance test model used in the present invention.
FIG. 7 is a current-voltage plot of the photovoltaic performance of the film product made in example 1.
FIG. 8 is an X-ray diffraction (XRD) pattern of the thin film product made in example 2.
Fig. 9 is a Scanning Electron Microscope (SEM) picture of the surface topography of the thin film product made in example 2.
FIG. 10 is a Scanning Electron Microscope (SEM) picture of the sectional morphology of the film product obtained in example 2.
FIG. 11 is a Scanning Electron Microscope (SEM) picture of the sectional morphology of the film product obtained in example 3.
FIG. 12 is a Scanning Electron Microscope (SEM) picture of the surface topography of the film product made in example 4.
FIG. 13 is a Scanning Electron Microscope (SEM) picture of the sectional morphology of the film product obtained in example 4.
FIG. 14 is a Scanning Electron Microscope (SEM) picture of the surface topography of the thin film product made in example 5.
FIG. 15 is a Scanning Electron Microscope (SEM) picture of the surface topography of the thin film product made in example 6.
FIG. 16 is a Scanning Electron Microscope (SEM) picture of the surface topography of the thin film product made in example 7.
Fig. 17 is a Scanning Electron Microscope (SEM) picture of the surface topography of the thin film product prepared in comparative example 1.
Fig. 18 is a surface topography Scanning Electron Microscope (SEM) picture of the thin film product obtained in comparative example 2.
Fig. 19 is a Scanning Electron Microscope (SEM) picture of the surface topography of the thin film product prepared in comparative example 3.
Fig. 20 is a current-voltage graph of photovoltaic performance of the thin film product made in comparative example 3.
Detailed Description
In order to better explain the present invention and to facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following examples are only illustrative of the present invention and do not represent or limit the scope of the claims, which are to be read in the light of the appended claims.
In the following examples and comparative examples, the reagents or instruments used are not indicated by the manufacturer, and are conventional products commercially available. The purities of the tetra-n-butyl titanate, the lead nitrate, the nickel nitrate hexahydrate and the ethylene glycol monomethyl ether are chemical purities. The purity of the potassium hydroxide was 85%. The ammonia water is commercial ammonia water, wherein NH 3The content is 25-28%. The niobium doped strontium titanate single crystal substrate has dimensions of 10mm x 5mm x 0.5mm and is oriented<100>The niobium content was 0.7 wt%. The reaction kettle is a polytetrafluoroethylene inner container and a closed reaction kettle with a stainless steel sleeve. The volume of the inner container of the reaction kettle is 45 ml. The nickel doping amount is the nickel doping amount, which means the mole percentage of nickel element in the total of titanium and nickel elements, and the unit is recorded as mol%. The room temperature is 20-25 ℃.
Example 1
1) Weighing 8.59g (0.130mol) of potassium hydroxide, placing the potassium hydroxide into an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 6.52 mol/L;
2) dissolving 0.09g (0.31mmol) of nickel nitrate hexahydrate in 30mL of ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate hexahydrate is completely dissolved; then 0.925g (2.72mmol) of tetra-n-butyl titanate is added into the solution and stirred for 2min again; then 1.242g (3.75mmol) of lead nitrate is added into the solution, and the solution is fully stirred for 30min until the lead nitrate is completely dissolved, so as to obtain a mixed solution;
3) dropwise adding the mixed solution prepared in the step 2) into 120mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2 hours to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) Washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction for 12 hours at 210 ℃, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
And (3) characterizing the composition, structure and appearance of the product:
XRD testing was performed on the film product obtained in example 1, and the XRD testing results are shown in FIG. 1. In FIG. 1, the curve PNTO-10% corresponds to the XRD spectrum of the thin film product obtained in example 1, and the curve PTO corresponds to single crystal lead titanate (PbTiO)3) XRD spectra of thin films, i.e. tetragonal phase PbTiO3Standard card of (JCPDS 70-0746). Comparing the two can find: the diffraction peaks on the curve PNTO-10% substantially coincide with those of PTO, indicating that the crystal structure of the film product obtained in example 1 is tetragonal phase PbTiO3The structure is not obviously changed due to nickel doping, and the orientation of the film is still<001>And (4) direction.
The film product obtained in example 1 was subjected to scanning electron microscope testing at 20kV, and the SEM photograph of the surface morphology thereof is shown in FIG. 2, and the SEM photograph of the sectional morphology thereof is shown in FIG. 3. As can be seen from fig. 2 and 3: the surface of the film is smooth and flat, and no particle deposition or hole formation occurs; meanwhile, the film also has a flat interface; the film thickness is uniform, and the film thickness is 3000nm through measurement, which is the sample thickness that the common technology for growing single crystal film (such as pulse laser deposition, chemical vapor deposition and other technologies) can not reach.
Meanwhile, the film section of the film product obtained in example 1 was subjected to X-ray energy spectrum analysis (EDS), and the obtained data are shown in table 1 (the test range is the area selected by the black frame in fig. 3):
table 1: EDS results of film sections of the film product obtained in example 1
Element(s) Weight percent of Atomic percent
O K 20.45 66.46
Ti K 15.82 17.17
Ni K 1.52 1.37
Sr L 0.30 0.18
Nb L 0.51 0.29
Pb M 61.4 14.53
Total amount of 100.00
As can be seen from the data in Table 1, the nickel doping amount of the film is 10 mol%, which is consistent with the charge ratio of the experimental design.
Further, the film interface and the film interior of the film product obtained in example 1 were characterized by using a spherical aberration-corrected field emission scanning transmission electron microscope (HAADF-STEM). HAADF-STEM pictures of the film at atomic level resolution at the interface, 500nm from the interface, 1000nm from the interface are shown in fig. 4a, 4b and 4c, respectively.
In FIG. 4a, the lighter areas represent the Ni-PTO (nickel doped PTO film) portion where the white dots are Pb atoms; the darker areas represent the Nb-doped STO-base fraction, with white dots of Sr atoms. Inside both regions, the Pb atom and the Sr atom both exhibit a highly ordered arrangement, and at the interface, the two atoms also achieve a high degree of mutual matching. From fig. 4a, the following conclusions can be drawn: the Ni: PTO/NSTO forms an atomically flat interface, and the epitaxial Ni: PTO film has orderly crystal lattice arrangement and good crystallinity.
FIGS. 4b and 4c show the atomic arrangement at 500nm and 1000nm from the interface, and it can be seen that: at two randomly selected locations, the film product obtained in example 1 (nickel-doped lead titanate film) exhibited excellent lattice arrangements within it, which is sufficient to demonstrate very good crystallinity throughout the nickel-doped lead titanate film.
FIG. 5 shows XRD of the thin film product obtained in example 1
Figure BDA0003068413420000081
And (5) scanning test results. As can be seen from FIG. 5, the thin film product obtained in example 1 was subjected to XRD
Figure BDA0003068413420000082
The scanning test shows four straight lines, and the interval between any two adjacent straight lines is 90 degrees, which indicates that the film product obtained in the example 1 is not randomly oriented but is a completely oriented single crystal, shows a quartic symmetrical structure and keeps good epitaxial relation with the substrate. It was found by analysis that the straight line in fig. 5 indicates the 101 diffraction peak of the PTO.
And (4) performance testing:
the photovoltaic effect is that when light is irradiated on an object, carriers (free electrons and holes) generated by light excitation still move inside the substance, so that the substance generates a photo-generated electromotive force. The test model is shown in fig. 6, laser is vertically incident to the surface of the sample, covers the tested silver electrode, and touches the surface of the electrode with a probe to receive a photovoltaic signal, and is externally connected with a keithley digital source meter to display current-voltage (I-V) information.
The film product obtained in example 1 was selected as a sample, a voltage of-1.5 to 1.5V was applied to the sample, and a current signal was recorded with 0.03V as a step length, and an I-V curve was obtained as shown in FIG. 7.
FIG. 7 shows: under the excitation of laser with the wavelength of 405nm, when the light intensity reaches 200mW/cm2Short circuit current is about 10.8 muA; when the light intensity reaches 400mW/cm2Short circuit current is about 19.3 μ A; when the light intensity reaches 600mW/cm2Short circuit current is about 28.6 muA; the open circuit voltage is always kept at 1.06V. Thus, it can be seen that: under the incidence of 405nm visible light, the short-circuit current is stronger and the intensity of the short-circuit current is equal to the incident lightThe intensity is close to proportional, and the sample shows good photovoltaic performance.
From the above test results, it can be found that: example 1 the product obtained was<001>Oriented nickel-doped lead titanate single crystal films with tetragonal phase of PbTiO3The structure, the nickel doping amount is 10 mol%; from the view of microscopic morphology, the surface of the film is smooth and flat, no obvious defect exists, the interface is in atomic level flatness, excellent lattice arrangement is shown in the film, and the integral crystallinity is good; the thickness of the film reaches 3 mu m, the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the nickel-doped lead titanate monocrystal film with large area and micron-sized thickness, which has a high-quality surface and an atomic-level flat interface, is presented on the whole. The film product obtained in example 1 has good photovoltaic properties: under the incidence of 405nm visible light, the short-circuit current is stronger and the intensity of the short-circuit current is approximately proportional to the intensity of the incident light.
Example 2
1) Weighing 7.30g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 5.53 mol/L;
2) dissolving 0.053g (0.182mmol) of nickel nitrate hexahydrate in 30mL of ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate hexahydrate is completely dissolved; then adding 1.987g (5.84mmol) of tetra-n-butyl titanate, stirring for 3min again, then adding 2.484g (7.50mmol) of lead nitrate, and continuing to stir fully for 40min at room temperature to obtain a mixed solution;
3) dropwise adding the mixed solution prepared in the step 2) into 120mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2.5h to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction at 210 ℃ for 12 hours, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
And (3) characterizing the composition, structure and appearance of the product:
XRD testing was performed on the thin film product obtained in example 2, and the XRD testing results are shown in FIG. 8. In FIG. 8, the curve PNTO-3% corresponds to the XRD spectrum of the thin film product obtained in example 2, and the curve PTO corresponds to single crystal lead titanate (PbTiO)3) XRD spectra of thin films, i.e. tetragonal phase PbTiO3Standard card of (JCPDS 70-0746). Comparing the two can find: the diffraction peaks on the curve PNTO-3% substantially coincide with those of PTO, indicating that the crystal structure of the thin film product obtained in example 2 is tetragonal phase PbTiO3The structure is not obviously changed due to nickel doping, and the orientation of the film is still<001>And (4) direction.
The film product obtained in example 2 was subjected to scanning electron microscope testing at 20kV, and the SEM photograph of the surface morphology thereof is shown in FIG. 9, and the SEM photograph of the sectional morphology thereof is shown in FIG. 10. As can be seen from fig. 9 and 10: the surface of the film is smooth and flat, and no particle deposition or hole formation occurs; meanwhile, the film also has a flat interface; the film thickness was measured to be 800 nm.
Meanwhile, the film section of the film product obtained in example 2 was subjected to X-ray energy spectrum analysis (EDS), and the EDS data result showed: the nickel doping amount of the film is 3 mol%, which is consistent with the charge ratio of experimental design.
The film product obtained in example 2 was subjected to
Figure BDA0003068413420000101
The HAADF-STEM, which was subjected to the sweep test and the spherical aberration correction, was observed to be a fully oriented single crystal, exhibiting excellent lattice arrangement in the inside of the thin film, good overall crystallinity, and an atomically flat interface.
From the above test results, it can be found that: example 2 the product obtainedIs composed of<001>Oriented nickel-doped lead titanate single crystal films with tetragonal phase of PbTiO3The structure, the nickel doping amount is 3 mol%; from the view of microscopic morphology, the surface of the film is smooth and flat, no obvious defect exists, the interface is in atomic level flatness, excellent lattice arrangement is shown in the film, and the integral crystallinity is good; the thickness of the film reaches 800nm, the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the nickel-doped lead titanate monocrystal film with large area and approximate micron-sized thickness and high-quality surface and atomic-level smooth interface is presented on the whole.
Example 3
1) Weighing 6.87g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 5.20 mol/L;
2) dissolving 0.018g (0.062mmol) of nickel nitrate hexahydrate in 30mL of ethylene glycol monomethyl ether, fully stirring until the nickel nitrate hexahydrate is completely dissolved, adding 2.03g (5.96mmol) of tetra-n-butyl titanate, stirring again for 10min, then adding 2.484g (7.50mmol) of lead nitrate, and continuing to stir fully for 60min at room temperature to obtain a mixed solution;
3) Dropwise adding the mixed solution prepared in the step 2) into 120mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2 hours to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction at 210 ℃ for 12 hours, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
And (3) characterizing the composition, structure and appearance of the product:
XRD test is carried out on the product obtained in example 3, and the XRD curve of the product is basically coincident with that of the single crystal lead titanate film and is tetragonal phase PbTiO3The structure shows that the crystal structure of the product is not obviously changed by doping nickel, and the orientation of the film is still <001>And (4) direction. The product obtained in the example 3 is tested by a scanning electron microscope under the voltage of 20kV, and the surface of the product is smooth and flat without obvious defects; the SEM photograph of the cross-sectional morphology is shown in FIG. 11, which has a flat interface and uniform thickness, and the film thickness is measured to be 750 nm. The film cut section of the film product obtained in example 3 was subjected to X-ray energy spectrum analysis (EDS), and the data obtained are shown in table 2 (the test range is the area selected by the black frame in fig. 11). As can be seen from the data in Table 2, the nickel doping amount of the film is 1 mol%, which is consistent with the charge ratio of the experimental design.
Table 2: EDS results of film section of film product obtained in example 3
Element(s) Weight percent of Atomic percent
O K 54.21 89.71
Ti K 8.97 4.96
Ni K 0.09 0.04
Sr L 4.19 1.27
Nb L -0.85 -0.24
Pb M 33.39 4.27
Total amount of 100.00
The film product obtained in example 3 was subjected to
Figure BDA0003068413420000111
The HAADF-STEM, which was subjected to the sweep test and the spherical aberration correction, was observed as a fully oriented single crystal, exhibiting excellent lattice arrangement in the inside of the thin film, good overall crystallinity, and atomically flat interface.
From the above test results, it can be found that: example 3 the resulting film product was<001>Oriented nickel-doped lead titanate single crystal film having tetragonal phase of PbTiO3The structure, the nickel doping amount is 1 mol%; from the view of microscopic morphology, the surface of the film is smooth and flat, no obvious defect exists, the interface is in atomic level flatness, excellent lattice arrangement is shown in the film, and the integral crystallinity is good; the thickness of the film reaches 750nm, the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the whole film is a large-area and near-micron-sized nickel-doped lead titanate monocrystal film with a high-quality surface and an atomic-level flat interface.
Example 4
1) Weighing 5.15g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 3.90 mol/L;
2) dissolving 0.073g (0.25mmol) of nickel nitrate hexahydrate in 30mL of ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate hexahydrate is completely dissolved; then 1.623g (4.77mmol) of tetra-n-butyl titanate is added into the solution and stirred for 10min again, then 2.07g (6.25mmol) of lead nitrate is added into the solution and stirred for 60min at room temperature to obtain a mixed solution;
3) dropwise adding the mixed solution prepared in the step 2) into 120mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 3h to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction at 210 ℃ for 12 hours, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
XRD, SEM, EDS, HAADF-STEM and HAADF-STEM were performed on the thin film product obtained in example 4 in the same manner as in example 1
Figure BDA0003068413420000121
And (3) performing a sweeping test to find that: example 4 the resulting film product was<001>Oriented nickel-doped lead titanate single crystal films with tetragonal phase of PbTiO3The structure, the nickel doping amount is 5 mol%; from the microscopic morphology, the surface of the film is smooth and flat, has no obvious defects, the interface is atomically flat, and the film is shown in the interiorExcellent lattice arrangement and good overall crystallinity are obtained; the film thickness is uniform and reaches 200nm, the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the whole film is a large-area nickel-doped lead titanate single crystal film with a high-quality surface and an atomic-level flat interface. The SEM photograph of the surface morphology is shown in FIG. 12, and the SEM photograph of the sectional morphology is shown in FIG. 13.
Example 5
1) Weighing 10.2g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 7.73 mol/L;
2) dissolving 0.009g (0.031mmol) of nickel nitrate hexahydrate in 15mL of ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate hexahydrate is completely dissolved; 1.015g (2.98mmol) of tetra-n-butyl titanate is added into the solution and stirred for 2min again; then 1.242g (3.75mmol) of lead nitrate is added into the solution, and the solution is continuously stirred for 30min at room temperature to obtain a mixed solution;
3) Dropwise adding the mixed solution prepared in the step 2) into 60mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle (the volume of the inner container of the reaction kettle is 45ml) by using deionized water, and stirring for 2 hours to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner with the reaction material (precursor suspension) prepared in the step 4), putting the reaction kettle liner with the precursor suspension into a reaction kettle, sealing, carrying out hydrothermal reaction for 24 hours at 200 ℃, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
XRD and S were carried out on the thin film product obtained in example 5 in the same manner as in example 1EM, EDS, HAADF-STEM and
Figure BDA0003068413420000131
and (3) performing a sweeping test to find that: example 5 the resulting thin film product was <001>Oriented nickel-doped lead titanate single crystal film having tetragonal phase of PbTiO3Structure, the nickel doping amount is 1 mol%; from the view of microscopic morphology, the surface of the film is smooth and flat, no obvious defect exists, the interface is in atomic level flatness, excellent lattice arrangement is shown in the film, and the integral crystallinity is good; the thickness of the film is uniform and reaches 1800 nm; the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the nickel-doped lead titanate monocrystal film with large area and micron-sized thickness and high-quality surface and atomic-level flat interface is presented on the whole. The SEM picture of the surface topography thereof is shown in fig. 14.
Example 6
1) Weighing 10.2g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 7.73 mol/L;
2) dissolving 0.027g (0.093mmol) of nickel nitrate hexahydrate in 10mL of ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate hexahydrate is completely dissolved; then 0.994g (2.92mmol) of tetra-n-butyl titanate is added into the solution, and the solution is stirred for 5min again; then 1.242g (3.75mmol) of lead nitrate is added into the solution, and the solution is continuously stirred for 40min at room temperature to obtain a mixed solution;
3) dropwise adding the mixed solution prepared in the step 2) into 60mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) Adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2h to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction for 6 hours at 220 ℃, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
XRD, SEM, EDS, HAADF-STEM and HIDE were carried out on the thin film product obtained in example 6 in the same manner as in example 1
Figure BDA0003068413420000141
And (4) performing a sweeping test to find that: example 6 the resulting thin film product was<001>Oriented nickel-doped lead titanate single crystal films with tetragonal phase of PbTiO3Structure, the nickel doping amount is 3 mol%; from the view of microscopic morphology, the surface of the film is smooth and flat, no obvious defect exists, the interface is in atomic level flatness, excellent lattice arrangement is shown in the film, and the integral crystallinity is good; the thickness of the film is uniform and reaches 700nm, the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the whole film is a large-area and near micron-sized nickel-doped lead titanate single crystal film with a high-quality surface and an atomic-level flat interface. The SEM picture of the surface topography thereof is shown in fig. 15.
Example 7
1) Weighing 5.15g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 3.90 mol/L;
2) dissolving 0.009g (0.031mmol) of nickel nitrate hexahydrate in 15mL of ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate hexahydrate is completely dissolved; 1.015g (2.98mmol) of tetra-n-butyl titanate is added into the solution and stirred for 2min again; then 1.10g (3.32mmol) of lead nitrate is added into the solution, and the solution is continuously stirred for 30min at room temperature to obtain a mixed solution;
3) dropwise adding the mixed solution prepared in the step 2) into 60mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) adding the flocculent precipitate obtained in the step 3) into the potassium hydroxide aqueous solution obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2h to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into the reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction at 210 ℃ for 12 hours, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
And (3) characterizing the morphology of the product:
XRD, SEM, EDS, HAADF-STEM and HIDE were carried out on the thin film product obtained in example 7 in the same manner as in example 1
Figure BDA0003068413420000151
And (4) performing a sweeping test to find that: example 7 the resulting thin film product was<001>Oriented nickel-doped lead titanate single crystal films with tetragonal phase of PbTiO3The structure, the nickel doping amount is 1 mol%; from the view of microscopic morphology, the surface of the film is smooth and flat, no obvious defect exists, the interface is in atomic level flatness, excellent lattice arrangement is shown in the film, and the integral crystallinity is good; the thickness of the film is uniform and reaches 2500nm, the area of the epitaxial film on the substrate is 8mm multiplied by 5mm, and the whole film is a large-area micron-sized nickel-doped lead titanate single crystal film with a high-quality surface and an atomic-level flat interface. The SEM picture of the surface topography is shown in fig. 16.
Comparative example 1
1) Weighing 6.87g (0.104mol) of potassium hydroxide, placing the potassium hydroxide into an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 5.20 mol/L;
2) 0.018g (0.062mmol) of nickel nitrate hexahydrate is dissolved in 10mL of ethylene glycol monomethyl ether and fully stirred until the nickel nitrate hexahydrate is completely dissolved; then adding 2.03g (5.96mmol) of tetra-n-butyl titanate into the solution, and stirring the solution for 20min to obtain a mixed solution;
3) Dropwise adding the mixed solution prepared in the step 2) into 60mL of ammonia water (excessive ammonia water), standing for 1h, and filtering to obtain flocculent precipitate;
4) weighing 2.484g (7.50mmol) of lead nitrate, dissolving in 5mL of deionized water, and fully stirring to obtain a lead nitrate aqueous solution;
5) adding the flocculent precipitate obtained in the step 3) and the aqueous solution of lead nitrate prepared in the step 4) into the aqueous solution of potassium hydroxide obtained in the step 1), adjusting the volume of the reaction material in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2 hours to disperse the precipitate to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
6) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into a reaction kettle liner provided with precursor suspension in the step 5), putting the reaction kettle liner into a reaction kettle, sealing, carrying out hydrothermal reaction for 12 hours at 210 ℃, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
The film product obtained in comparative example 1 was subjected to scanning electron microscope test at 20kV voltage, and SEM picture (as shown in FIG. 17) of the surface morphology shows that: there are many dark round holes, which are the holes formed, and in the observation range, there are many holes formed on the surface of the film, which can not be connected into a smooth and flat film. That is, in comparative example 1, the doped transition metal element Ni and Ti were mixed first, and coprecipitation was performed with ammonia water as a precipitant; then the solution is subjected to hydrothermal reaction with a lead nitrate aqueous solution and a potassium hydroxide aqueous solution, and a smooth and flat film cannot be obtained.
Comparative example 2
1) Weighing 6.87g (0.104mol) of potassium hydroxide, placing the potassium hydroxide into an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 5.20 mol/L;
2) adding 1.708g (5.02mmol) of tetra-n-butyl titanate into the potassium hydroxide aqueous solution prepared in the step 1) under the stirring state, and stirring for 10min to obtain a suspension;
3) weighing 2.484g (7.50mmol) of lead nitrate, dissolving in 5ml of deionized water, and fully stirring until the lead nitrate is completely dissolved to obtain a lead nitrate aqueous solution;
4) weighing 0.018g (0.062mmol) of nickel nitrate hexahydrate, dissolving in 5ml of deionized water, and fully stirring until the nickel nitrate hexahydrate is completely dissolved to obtain a nickel nitrate hexahydrate aqueous solution;
5) adding the lead nitrate aqueous solution prepared in the step 3) and the nickel nitrate hexahydrate aqueous solution prepared in the step 4) into the suspension obtained in the step 2), adjusting the volume of the reaction materials in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2h to obtain a precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
6) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into a reaction kettle liner provided with precursor suspension in the step 5), putting the reaction kettle liner into a reaction kettle, sealing, carrying out hydrothermal reaction for 12 hours at 210 ℃, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol repeatedly respectively, filtering and drying to obtain a film product.
Scanning electron microscope testing is carried out on the product obtained in the comparative example 2 under the voltage of 20kV, and SEM pictures (shown in figure 18) of the surface morphology show that the method can be observed not to form a continuous film, and only the stacking growth of the nickel-doped lead titanate particles is realized. In an observation range, the surface of the substrate is covered with a large number of nickel-doped lead titanate small particles, a part of regions are spliced into a film with a minimum area, and most of the spliced traces of the particles are reserved. That is, in comparative example 2, the nickel nitrate hexahydrate aqueous solution and the lead nitrate aqueous solution were directly subjected to the hydrothermal reaction with the mixed solution of tetra-n-butyl titanate and potassium hydroxide, and a complete thin film could not be obtained, and lead titanate mainly grew in island form, and most of the lead titanate particles were stacked and spliced.
It can be seen that either a single hydrothermal reaction (comparative example 2) or partial coprecipitation (the coprecipitation of comparative example 1 complexes only Ti and Ni elements) does not result in a complete high quality large area film. Because the film is discontinuous, the phenomenon of electric leakage can appear in photovoltaic test, and the film formed by particle accumulation has more defects, so that photon-generated carriers are compounded at the defects, and the photovoltaic performance can be greatly reduced. Thus, the samples of comparative examples 1 and 2 did not present the necessity of performing photovoltaic tests.
Comparative example 3 preparation of undoped PTO film
1) Weighing 8.4g of potassium hydroxide, placing the potassium hydroxide in an inner container of a polytetrafluoroethylene reaction kettle, adding 20mL of deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 6.36 mol/L;
2) adding 1.708g (5.02mmol) of tetra-n-butyl titanate into the potassium hydroxide aqueous solution prepared in the step 1) under the stirring state, and stirring for 10min to obtain a suspension;
3) weighing 2.07g (6.25mmol) of lead nitrate, dissolving in deionized water, and fully stirring until the lead nitrate is completely dissolved to obtain a lead nitrate aqueous solution; the molar ratio of lead to titanium is 1.25;
4) adding the lead nitrate aqueous solution prepared in the step 3) into the suspension obtained in the step 2), adjusting the volume of the reaction materials in the inner container of the reaction kettle to 80% of the volume of the inner container of the reaction kettle by using deionized water, and stirring for 2h to obtain precursor suspension, wherein the total volume of the precursor suspension is 36 ml;
5) washing the niobium-doped strontium titanate single crystal substrate with acetone, ethanol and deionized water respectively, fixing the substrate on a polytetrafluoroethylene support, putting the substrate into a reaction kettle liner provided with precursor suspension in the step 4), putting the reaction kettle liner into the reaction kettle, sealing, carrying out hydrothermal reaction for 12h at 200 ℃, naturally cooling the reaction kettle to room temperature, unloading the reaction kettle, washing reaction products with deionized water and absolute ethyl alcohol respectively, filtering and drying to obtain a film product.
By XRD and EDS test, the film product is determined to be lead titanate film with strontium niobate-doped titanate as substrate. The SEM photograph of the surface morphology thereof is shown in fig. 19. It can be seen that: the surface of the film is smooth and flat, and no particle deposition or hole is formed.
Carrying out photovoltaic test on the sample, and testing conditions andthe same applies to example 1. And applying a voltage of-1.5V to two ends of the sample, taking 0.03V as a step length, and recording a current signal to obtain an I-V curve as shown in figure 20. As can be seen from fig. 20: under the excitation of laser with the wavelength of 405nm, when the light intensity reaches 200mW/cm2Short circuit current is about 2.85 muA; when the light intensity reaches 400mW/cm2Short circuit current is about 5.05 μ A; when the light intensity reaches 600mW/cm2The short-circuit current is about 7.16 muA, and the open-circuit voltage is always lower than 1V.
In comparison with the test results (fig. 7) of the film product obtained in the foregoing example 1 as a sample, it can be seen that: compared with the sample of the film product obtained in the comparative example 3, the visible light photovoltaic performance of the film product obtained in the example 1 is obviously improved: under the same illumination intensity, the short-circuit photocurrent is improved by over 200 percent.
In conclusion, the nickel-doped lead titanate single crystal film prepared by the invention has a smooth and flat surface, a high-quality interface and a thickness reaching micron level, shows excellent photovoltaic performance, has strong short-circuit current, is in direct proportion to light intensity, meets the material requirement of a passive photoelectric detector, effectively solves the problem that a thick film is difficult to grow in the conventional single crystal film preparation technology, and is convenient for processing and manufacturing devices. Moreover, the preparation method is simple, the process is easy to operate, the raw materials are simple and easy to obtain, the product purity is high, and the crystallinity is good.
It will thus be seen that the objects of the invention have been fully and effectively accomplished. The functional and structural principles of the present invention have been shown and described in the embodiments, and the embodiments may be modified without departing from the principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the claims.

Claims (9)

1. The nickel-doped lead titanate monocrystal film has a flat surface and a flat interface, the thickness of the film is 200-3000 nm, the doping amount of nickel is 1-10 mol%, and the doping amount of nickel is the mole percentage of nickel element in the sum of titanium and nickel elements.
2. The method for preparing a nickel-doped lead titanate single crystal thin film according to claim 1, comprising the steps of:
(1) adding potassium hydroxide into an inner container of a reaction kettle, adding deionized water for dissolving, and fully stirring to obtain a potassium hydroxide aqueous solution with the molar concentration of 3.9-7.8 mol/L;
(2) dissolving nickel nitrate hexahydrate in ethylene glycol monomethyl ether, and fully stirring until the nickel nitrate is completely dissolved; then adding tetra-n-butyl titanate into the mixture, and stirring for 2-30 min; adding lead nitrate into the mixed solution, and fully stirring the mixture until the lead nitrate is completely dissolved to obtain a mixed solution; the molar ratio of the sum of Ti and Ni elements to Pb element is 1: (1.1-1.5); the nickel element accounts for 1-10 mol% of the sum of the titanium and the nickel element;
(3) Dropwise adding the mixed solution prepared in the step (2) into excessive ammonia water, standing for 0.5-3 hours after dropwise adding is finished, and filtering to obtain flocculent precipitate;
(4) adding the flocculent precipitate obtained in the step (3) into the potassium hydroxide aqueous solution obtained in the step (1), adding deionized water into the flocculent precipitate to enable the final volume to reach 80-90% of the volume of the inner container of the reaction kettle, and stirring for 2-3 h to disperse the precipitate to obtain a precursor suspension; in the precursor suspension, the molar ratio of the sum of Ti and Ni elements to K element is 1: (10-100);
(5) placing the strontium niobate-doped titanate single crystal substrate into the precursor suspension, placing the inner container of the reaction kettle filled with the precursor suspension into the reaction kettle, sealing, and keeping at 200-220 ℃ for 6-24 hours to perform hydrothermal reaction; then, the reaction kettle is naturally cooled to room temperature; and after the kettle is unloaded, washing the reaction product, filtering and drying to obtain the nickel-doped lead titanate single crystal film.
3. The method for preparing a nickel-doped lead titanate single crystal thin film according to claim 2, wherein in the step (2), the ratio of the sum of Ti and Ni elements to Pb element is 1: (1.1-1.25).
4. The method for preparing a nickel-doped lead titanate single crystal film according to claim 2, wherein in the step (2), after the lead nitrate is added, the stirring time is 30 to 60 min.
5. The method for preparing a nickel-doped lead titanate single crystal thin film according to claim 2, wherein in the step (2), nickel nitrate hexahydrate is dissolved in ethylene glycol monomethyl ether to form a solution, and the molar concentration of nickel nitrate hexahydrate is 0.001-0.015 mol/L.
6. The method for preparing a nickel-doped lead titanate single crystal thin film according to claim 2, wherein in the step (3), the excessive ammonia water means that the molar ratio of the sum of Ti and Ni elements to ammonia water is 1: (200-600).
7. The method for preparing a nickel-doped lead titanate single crystal film according to claim 2, wherein in the step (5), the orientation of the strontium niobate-doped titanate single crystal in the strontium niobate-doped titanate single crystal substrate is <100 >.
8. The use of the nickel-doped lead titanate single crystal thin film according to claim 1 in ferroelectric memories, pyroelectric sensors, optical waveguides, optical detection or electro-optical switches.
9. The nickel-doped lead titanate single crystal film prepared by the preparation method according to any one of claims 2 to 7 is applied to ferroelectric memories, pyroelectric sensors, optical waveguides, optical detection or electro-optical switches.
CN202110532409.8A 2021-05-17 2021-05-17 Nickel-doped lead titanate single crystal film and preparation and application thereof Active CN113279062B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110532409.8A CN113279062B (en) 2021-05-17 2021-05-17 Nickel-doped lead titanate single crystal film and preparation and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110532409.8A CN113279062B (en) 2021-05-17 2021-05-17 Nickel-doped lead titanate single crystal film and preparation and application thereof

Publications (2)

Publication Number Publication Date
CN113279062A CN113279062A (en) 2021-08-20
CN113279062B true CN113279062B (en) 2022-07-08

Family

ID=77279356

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110532409.8A Active CN113279062B (en) 2021-05-17 2021-05-17 Nickel-doped lead titanate single crystal film and preparation and application thereof

Country Status (1)

Country Link
CN (1) CN113279062B (en)

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006232585A (en) * 2005-02-23 2006-09-07 Tohoku Univ METHOD OF MANUFACTURING FERROELECTRIC THIN FILM SINGLE CRYSTAL OF PbTiO3 OR Pb(ZrTi)O3
CN102140694A (en) * 2011-03-18 2011-08-03 浙江大学 Preparation method of barium-doped lead titanate monocrystal nano fiber with one-dimensional column structure
CN102140693A (en) * 2011-03-18 2011-08-03 浙江大学 Method for preparing zirconium-doped lead titanate single crystal nanofiber with one-dimensional columnar structure
CN102154702A (en) * 2011-03-18 2011-08-17 浙江大学 Preparation method of iron-doped lead titanate single-crystal nanofibre with one-dimensional columnar structure
CN102181930A (en) * 2011-04-20 2011-09-14 浙江大学 Method for preparing one-dimensional columnar structure calcium-doped lead titanate monocrystal nano-fibers
CN102534794A (en) * 2012-02-17 2012-07-04 浙江大学 Preparation method for perovskite lead titanate single-crystal nanometer sheet
CN102923766A (en) * 2012-11-14 2013-02-13 浙江大学 Preparation method of lead-titanate ceramic single-crystal nanosheet
CN103603045A (en) * 2013-10-22 2014-02-26 浙江大学 Preparation method of erbium doped tetragonal phase lead titanate monocrystal nano fiber with perovskite structure
CN109825874A (en) * 2019-03-26 2019-05-31 浙江大学 A kind of preparation method of monocrystalline lead titanate thin film
CN109879310A (en) * 2019-03-26 2019-06-14 浙江大学 A kind of preparation method of single-crystal strontium titanate film
CN110128134A (en) * 2019-05-24 2019-08-16 浙江大学 It is a kind of using niobium-doped strontium titanate as the preparation method of the lead titanate thin film of substrate
CN110791732A (en) * 2019-11-15 2020-02-14 福建师范大学 Preparation method of nickel-doped bismuth ferrite film system material

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006232585A (en) * 2005-02-23 2006-09-07 Tohoku Univ METHOD OF MANUFACTURING FERROELECTRIC THIN FILM SINGLE CRYSTAL OF PbTiO3 OR Pb(ZrTi)O3
CN102140694A (en) * 2011-03-18 2011-08-03 浙江大学 Preparation method of barium-doped lead titanate monocrystal nano fiber with one-dimensional column structure
CN102140693A (en) * 2011-03-18 2011-08-03 浙江大学 Method for preparing zirconium-doped lead titanate single crystal nanofiber with one-dimensional columnar structure
CN102154702A (en) * 2011-03-18 2011-08-17 浙江大学 Preparation method of iron-doped lead titanate single-crystal nanofibre with one-dimensional columnar structure
CN102181930A (en) * 2011-04-20 2011-09-14 浙江大学 Method for preparing one-dimensional columnar structure calcium-doped lead titanate monocrystal nano-fibers
CN102534794A (en) * 2012-02-17 2012-07-04 浙江大学 Preparation method for perovskite lead titanate single-crystal nanometer sheet
CN102923766A (en) * 2012-11-14 2013-02-13 浙江大学 Preparation method of lead-titanate ceramic single-crystal nanosheet
CN103603045A (en) * 2013-10-22 2014-02-26 浙江大学 Preparation method of erbium doped tetragonal phase lead titanate monocrystal nano fiber with perovskite structure
CN109825874A (en) * 2019-03-26 2019-05-31 浙江大学 A kind of preparation method of monocrystalline lead titanate thin film
CN109879310A (en) * 2019-03-26 2019-06-14 浙江大学 A kind of preparation method of single-crystal strontium titanate film
CN110128134A (en) * 2019-05-24 2019-08-16 浙江大学 It is a kind of using niobium-doped strontium titanate as the preparation method of the lead titanate thin film of substrate
CN110791732A (en) * 2019-11-15 2020-02-14 福建师范大学 Preparation method of nickel-doped bismuth ferrite film system material

Also Published As

Publication number Publication date
CN113279062A (en) 2021-08-20

Similar Documents

Publication Publication Date Title
Souza et al. Nanostructured hematite thin films produced by spin-coating deposition solution: Application in water splitting
Lin et al. Effects of annealing temperature on the microstructure, optical, ferroelectric and photovoltaic properties of BiFeO3 thin films prepared by sol–gel method
Suresh et al. Influence of substrate temperature on the properties of CeO2 thin films by simple nebulizer spray pyrolysis technique
Abou Hammad et al. Ni2+ doping effect on potassium barium titanate nanoparticles: enhancement optical and dielectric properties
Zeribi et al. Dependence of the physical properties of titanium dioxide (TiO2) thin films grown by sol-gel (spin-coating) process on thickness
Goumri-Said et al. Europium incorporation dynamics within NiO films deposited by sol-gel spin coating: experimental and theoretical studies
Ivanova et al. Structural and optical characterization of nitrogen and gallium co-doped ZnO thin films, deposited by sol-gel method
Sypniewska et al. Structural, morphological and photoluminescent properties of annealed ZnO thin layers obtained by the rapid sol-gel spin-coating method
Thakur et al. Structural and optical study of nickel doped ZnO nanoparticles and thin films for dye sensitized solar cell applications
Eskandari et al. Growth of Al-doped ZnO nanorod arrays on the substrate at low temperature
Farhad et al. Synthesis and characterization of c-axis oriented Zinc Oxide thin film and its use for the subsequent hydrothermal growth of Zinc Oxide nanorods
Shoghi et al. Sol–gel synthesis of PZT thin films on FTO glass substrates for electro-optic devices
Hosseini et al. Optimizing physical properties of BiFe1-xMnxO3 perovskite thin films via a low-temperature sol-gel method
Lenzmann et al. Mesoporous Nb 2 O 5 films: influence of degree of crystallinity on properties
CN113279062B (en) Nickel-doped lead titanate single crystal film and preparation and application thereof
Kahouli et al. Enhanced structural and optical properties of ZnO nanopowder with tailored visible luminescence as a function of sodium hydroxide to zinc sulfate mass ratio
CN110246958B (en) Method for improving photoelectric response of BFO/ZnO heterojunction device
CN113249789B (en) Single crystal lead zirconate titanate film and preparation and application thereof
CN101697354B (en) Transparent extended p-n heterojunction thin film and preparation method thereof
Ankita et al. Nanopowder and thin films of ZnO by sol gel approach
Kayani et al. Growth and characterization of iron oxide nanocrystalline thin films via sol-gel dip coating method
Anh et al. Investigation of optical properties on BaSnO3 materials
Abdelbaki et al. Synthesis and Characterization of Al-doped NiO Nanostructured Thin Films Elaborated by Solar Spray Pyrolysis Technique, for Photovoltaic Cells
Srinivasa et al. Preparation and characterization of Sn doped NiO thin films by sol–gel spin coating technique
CN117305981A (en) Potassium niobate single crystal film, preparation and application thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant