阅读说明：本技术 一种铌掺杂二氧化钛纳米材料的制备方法及其应用 (Preparation method and application of niobium-doped titanium dioxide nano material ) 是由 陈加藏 程昌 于 2020-04-24 设计创作，主要内容包括：本申请涉及新能源领域,尤其涉及钙钛矿电池(PSCs)中一种铌掺杂纳米二氧化钛的制备和应用。铌掺杂纳米二氧化钛材料的具体制备方法如下：首先,将一定量的五水合五氯化铌、钛酸四异丙酯和冰醋酸置于聚四氟乙烯反应釜,220℃,12h后过滤洗涤干燥得到未烧结的铌掺杂二氧化钛；接着,将其先与松油醇一起球磨,后加入乙基纤维素热搅拌,再用无水乙醇稀释得到介孔层二氧化钛前驱体溶液；最后,将其旋涂均布在致密层二氧化钛之上,并于空气中煅烧若干小时得到内部富集铌的二氧化钛材料组成的介孔层。以该材料为介孔层所制备的介观型PSCs与未掺杂铌的普通二氧化钛相比,介观型PSCs光电转化效率提升的同时,显著改善了介观型PSCs的热稳定性和紫外稳定性。(The application relates to the field of new energy, in particular to preparation and application of niobium-doped nano titanium dioxide in perovskite batteries (PSCs). The specific preparation method of the niobium-doped nano titanium dioxide material comprises the following steps: firstly, putting a certain amount of niobium pentachloride pentahydrate, tetraisopropyl titanate and glacial acetic acid into a polytetrafluoroethylene reaction kettle, filtering, washing and drying at 220 ℃ for 12h to obtain unsintered niobium doped titanium dioxide; then, ball-milling the mesoporous titanium dioxide precursor solution and terpineol, adding ethyl cellulose, thermally stirring, and diluting with absolute ethyl alcohol to obtain a mesoporous titanium dioxide precursor solution; and finally, uniformly coating the titanium dioxide on the dense layer in a spin coating manner, and calcining the titanium dioxide in the air for a plurality of hours to obtain the mesoporous layer consisting of the titanium dioxide material with the niobium enriched inside. Compared with the common titanium dioxide not doped with niobium, the mesoscopic PSCs prepared by taking the material as the mesoporous layer have the advantages that the photoelectric conversion efficiency of the mesoscopic PSCs is improved, and meanwhile, the thermal stability and the ultraviolet stability of the mesoscopic PSCs are obviously improved.)

1. A method for synthesizing niobium-doped titanium dioxide nano material is characterized by comprising the following steps:

adding weighed tetrabutyl titanate and niobium chloride pentahydrate into a beaker according to a certain proportion, uniformly mixing and stirring to obtain a solution A, then adding glacial acetic acid into the solution A, and stirring for 15-20min to obtain a solution B; then transferring the solution B into a hydrothermal reaction kettle for hydrothermal reaction at 220 ℃ for 12 hours, and cooling to room temperature to obtain a niobium-doped titanium dioxide colloid substance; and finally, centrifuging, washing and drying the colloidal substance to obtain the niobium-doped titanium dioxide nano material.

2. The method for synthesizing the niobium-doped titanium dioxide nano material as claimed in claim 1, wherein the ratio of the tetrabutyl titanate, the niobium chloride pentahydrate and the glacial acetic acid is 10m L: 0.0529-0.2117 g:3.4224m L.

3. The method for synthesizing the niobium doped titanium dioxide nano-material as claimed in claim 1, wherein the washing is performed by absolute ethyl alcohol, and the drying is performed at 80 ℃ for 12 h.

4. A niobium doped titania nanomaterial synthesized by the method of any one of claims 1-3.

5. The application of the niobium-doped titanium dioxide nanomaterial of claim 4 in preparing a mesoporous layer of a mesoscopic perovskite solar cell is characterized in that the preparation method of the mesoporous layer comprises the following steps:

weighing the prepared niobium-doped titanium dioxide nano material, grinding the material into powder, adding terpineol and ethanol, then adding ethyl cellulose under heating and stirring, uniformly stirring, and carrying out ball milling at room temperature to obtain a white colloid substance; then, diluting the obtained white colloidal substance with ethanol to obtain a mesoporous layer precursor solution; and (3) dripping the prepared mesoporous layer precursor solution onto the prepared compact layer titanium dioxide, performing spin coating after the compact layer titanium dioxide flows and is fully paved, and roasting in the air to obtain the mesoporous layer of the mesoscopic perovskite solar cell consisting of the niobium-doped titanium dioxide nano material.

6. The application of the niobium-doped titanium dioxide nanomaterial in preparing a mesoporous layer of a mesoscopic perovskite solar cell according to claim 5, wherein the preparation method of the dense-layer titanium dioxide comprises the following steps:

the precursor solution of the titanium dioxide of the dense layer is prepared by mixing absolute ethyl alcohol, hydrochloric acid and diisopropyl di (acetylacetonate) titanate, and the precursor solution of the titanium dioxide of the dense layer is attached to the FTO glass by adopting a thermal spraying technology, so that the titanium dioxide of the dense layer is obtained.

7. The application of the niobium-doped titanium dioxide nanomaterial in preparing the mesoporous layer of the mesoscopic perovskite solar cell as claimed in claims 5-6, wherein the mass ratio of the niobium-doped titanium dioxide nanomaterial to terpineol to ethyl cellulose is 1:2:4, the addition amount of ethanol before heating and stirring is 3ml for each gram of niobium-doped titanium dioxide nanomaterial, the heating temperature under stirring is 60 ℃, the dilution amount of ethanol is 8.5ml for each gram of white colloid substance, the spin-coating rotation speed is 5000rmp, the spin-coating time is 30s, and the spin-coating acceleration is 3000 rmp/s.

8. The application of the niobium-doped titanium dioxide nanomaterial in preparing the mesoporous layer of the mesoscopic perovskite solar cell according to claims 5-7 is characterized in that the roasting temperature is 450-550 ℃, and the roasting time is 10-40 min.

9. The application of the niobium-doped titanium dioxide nanomaterial in preparing a mesoporous layer of a mesoscopic perovskite solar cell as claimed in claim 5, wherein the thickness of the mesoporous layer of the mesoscopic perovskite solar cell consisting of the niobium-doped titanium dioxide nanomaterial is 150-200 nm.

10. Use of niobium doped titania nanomaterial according to any of claims 6-9 in the preparation of mesoporous layers for mesoscopic perovskite solar cells, characterized in that the FTO glass uses 30-45 μ L mesoporous layer precursor solution per square centimeter.

Technical Field

The invention relates to the field of new energy, in particular to a niobium-doped titanium dioxide nano material, a synthesis method and application of the niobium-doped titanium dioxide nano material as a mesoporous layer in Perovskite Solar Cells (PSCs for short).

Background

With the increasing demand for energy from human beings, the application of traditional fossil fuels is also more extensive. However, the use of non-renewable fossil fuels in large quantities also poses a number of problems, such as energy crisis, environmental pollution, etc. Among many new energy sources, solar energy is widely concerned due to its green, environmental protection, large storage capacity, and no geographical restriction.

Perovskite solar cells have been a research hotspot since being discovered as a brand new solar energy utilization mode. Through the continuous efforts of a plurality of researchers, the cell efficiency of the perovskite is improved to 25.2% from the initial 2.3%, and the performance of the perovskite can be comparable to that of a crystalline silicon solar cell obtained under the laboratory condition. Compared with the crystalline silicon solar cell, the novel PSCs have the advantages of simple manufacturing process, lower cost and higher theoretical photoelectric conversion efficiency.

PSCs have a variety of structures, the two most typical of which are mesoscopic and planar. The invention mainly researches mesoscopic PSCs, and the structure mainly comprises a conductive glass substrate, a charge transport layer, a mesoporous layer, a perovskite layer, a hole transport layer and a counter electrode. At present, TiO is adopted by most mesoscopic PSCs₂As a mesoporous layer. TiO compared with other semiconductor materials₂Has the advantages of high forbidden band width, good photocatalytic activity and photoelectric property, no toxicity and low cost. However, when the mesoporous material is used as a mesoporous layer, the thermal stability and the ultraviolet stability of the perovskite battery are poor, and the service life and the service performance of the perovskite battery are influenced.

Disclosure of Invention

To overcome the single TiO₂The invention provides a niobium-doped titanium dioxide nano material, a preparation method and application thereof as a mesoporous layer in a mesoscopic perovskite solar cell, and solves the problem that the thermal stability and the ultraviolet stability of the perovskite solar cell are poor when the material is used as the mesoporous layer.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for synthesizing niobium-doped titanium dioxide nano material comprises the following steps:

adding weighed tetrabutyl titanate and niobium chloride pentahydrate into a beaker according to a certain proportion, uniformly mixing and stirring to obtain a solution A, then adding glacial acetic acid into the solution A, and stirring for 15-20min to obtain a solution B; then transferring the solution B into a hydrothermal reaction kettle for hydrothermal reaction at 220 ℃ for 12 hours, and cooling to room temperature to obtain a niobium-doped titanium dioxide colloid substance; and finally, centrifuging, washing and drying the colloidal substance to obtain the niobium-doped titanium dioxide nano material.

Preferably, the ratio of tetrabutyl titanate, niobium chloride pentahydrate and glacial acetic acid is 10m L: 0.0529-0.2117 g:3.4224m L.

Preferably, the washing is carried out by absolute ethyl alcohol, the drying temperature is 80 ℃, and the drying time is 12 h.

In addition, the invention also claims the niobium-doped titanium dioxide nano material prepared by the method and the application of the niobium-doped titanium dioxide nano material in preparing a mesoporous layer of a mesoscopic perovskite solar cell, wherein the preparation method of the mesoporous layer of the mesoscopic perovskite solar cell comprises the following steps:

weighing the prepared niobium-doped titanium dioxide nano material, grinding the material into powder, adding terpineol and ethanol, then adding ethyl cellulose under heating and stirring, uniformly stirring, and carrying out ball milling at room temperature to obtain a white colloid substance; then, diluting the obtained white colloidal substance with ethanol to obtain a mesoporous layer precursor solution; and (3) dripping the prepared mesoporous layer precursor solution onto the prepared compact layer titanium dioxide, performing spin coating after the compact layer titanium dioxide flows and is fully paved, and roasting in the air to obtain the mesoporous layer of the mesoscopic perovskite solar cell consisting of the niobium-doped titanium dioxide nano material.

Preferably, the dense layer titanium dioxide is prepared as follows: the precursor solution of the titanium dioxide of the dense layer is prepared by mixing absolute ethyl alcohol, hydrochloric acid and diisopropyl di (acetylacetonate) titanate, and the precursor solution of the titanium dioxide of the dense layer is attached to the FTO glass by adopting a thermal spraying technology, so that the titanium dioxide of the dense layer is obtained.

Preferably, the mass ratio of the niobium-doped titanium dioxide nano material to terpineol to ethyl cellulose is 1:2:4, the adding amount of ethanol before heating and stirring is 3ml for each gram of niobium-doped titanium dioxide nano material, the heating temperature under stirring is 60 ℃, the diluting amount of ethanol is 8.5ml for each gram of white colloid material, the spin-coating speed is 5000rmp, the spin-coating time is 30s, and the spin-coating acceleration is 3000 rmp/s.

Preferably, the roasting temperature is 450-550 ℃, and the roasting time is 10-40 min.

Preferably, the thickness of the meso-porous layer of the meso-perovskite solar cell, which is composed of the niobium-doped titanium dioxide nano material, is 150-200 nm.

Preferably, the FTO glass uses 30-45 μ L mesoporous layer precursor solution per square centimeter.

After the meso-porous layer of the meso-perovskite solar cell consisting of the niobium-containing doped titanium dioxide nano material is prepared by the method, a final meso-perovskite solar cell product can be obtained only by preparing a perovskite layer, preparing a hole transport layer and preparing a counter electrode, wherein the preparation of the perovskite layer, the preparation of the hole transport layer and the preparation of the counter electrode are as follows:

preparation of perovskite layer: the perovskite precursor is prepared by mixing methyl ammonium bromide, formamidine hydroiodide, lead bromide, lead iodide, N-N dimethylformamide and dimethyl sulfoxide; spin-coating the prepared perovskite precursor into a mesoscopic perovskite solar cell semi-finished product taking the niobium-doped titanium dioxide nano material as a mesoporous layer, and heating at 100 ℃ for 30min to obtain a perovskite layer;

preparation of hole transport layer: the hole transport layer precursor solution is prepared from 2,2',7,7' -tetra [ N, N-di (4-methoxyphenyl) amino ] -9,9' -spirobifluorene (Spiro-OMeTAD), anhydrous chlorobenzene, 4-tert-butylpyridine, a lithium bistrifluoromethanesulfonylimide solution and a cobalt-based bistrifluoromethanesulfonylimide salt solution, and the prepared hole transport layer precursor solution is spin-coated on the prepared perovskite layer;

preparing a counter electrode: and (3) putting the mesoscopic perovskite solar cell semi-finished product with the hole transport layer prepared into a mask plate, and evaporating a layer of metal counter electrode under the vacuum degree by adopting a vacuum coating method to complete the preparation of PSCs.

The mesoscopic perovskite solar cell prepared by the invention has a structural schematic diagram shown in figure 1, and is sequentially provided with an FTO glass substrate (1) from bottom to top; a dense layer titanium dioxide (2); a mesoporous layer (3); a perovskite layer (4); a hole transport layer (5); a counter electrode (6).

The technical scheme provided by the invention has the following obvious beneficial effects:

(1) according to the invention, the niobium-doped titanium dioxide nano material is calcined, and niobium is enriched in the titanium dioxide, so that the doping effect of niobium is ensured.

(2) According to the invention, the titanium dioxide material is doped with niobium, so that the niobium-doped mesoporous layer and the perovskite layer are better matched. Among PSCs, perovskite and anatase TiO₂The lattice mismatch therebetween becomes severe with increasing temperature because perovskites have a higher coefficient of thermal expansion than TiO₂By a factor of about 3, the strain generated internally in the doped niobium material of the present application may act on the surface and may enlarge the lattice spacing of the undoped region, may effectively mitigate the lattice mismatch, and may reduce the lattice strain generated between anatase and perovskite.

(3) Compared with PSCs prepared by taking titanium dioxide materials without niobium as mesoporous layers, PSCs prepared by taking niobium-doped titanium dioxide nano materials as mesoporous layers have obviously slow photoelectric conversion efficiency reduction rate along with the prolonging of heating time; with the extension of the ultraviolet irradiation time, the photoelectric conversion efficiency is reduced to a certain degree and then tends to be stabilized at a higher value. The PSCs prepared by taking the niobium-doped titanium dioxide nano material as the mesoporous layer have better thermal stability and ultraviolet stability, and show that the PSCs prepared by the niobium-doped titanium dioxide nano material can endure harsher use environment, have wider use occasions and have better applicability; meanwhile, from the viewpoint of photoelectric conversion efficiency, the maximum PSCs manufactured by using the niobium-doped titanium dioxide nano material as the mesoporous layer can reach 21.07%, while the photoelectric conversion efficiency of the PSCs manufactured by using the non-niobium-doped titanium dioxide material as the mesoporous layer is only 20.3%, so that the photoelectric conversion efficiency is improved to a certain extent, and the utilization efficiency of solar energy resources can be improved. In a word, the invention provides a synthesis method of a complete niobium-doped titanium dioxide nano material and application of the complete niobium-doped titanium dioxide nano material in a mesoscopic perovskite solar cell, the whole process is simple, the prepared PSCs have good thermal stability and ultraviolet stability, the service performance of the PSCs is improved, the PSCs have wide market prospect, better utilization of solar resources is facilitated, the use ratio of the solar resources is improved, fossil energy consumption can be reduced to a certain extent, and the invention has double meanings of good economic benefit and high environmental protection benefit.

Drawings

FIG. 1 is a schematic structural diagram of mesoscopic PSCs assembled according to the present invention.

FIG. 2 is a comparison of XPS before and after calcination of the niobium doped titanium dioxide nanomaterial of the present invention. It can be analyzed from the figure that the doped Nb is mainly enriched on the surface before calcination, and the Nb is enriched in the titanium dioxide after high-temperature heat treatment at 500 ℃.

FIG. 3 is a graph showing the photoelectric conversion efficiency of PSCs fabricated by using titanium dioxide with different Nb/Ti molar doping ratios as mesoporous layers and PSCs fabricated by using titanium dioxide material without niobium doping as mesoporous layers in the present invention. As can be seen from the figure, PSCs prepared by using titanium dioxide doped with 1% Nb as a mesoporous layer have the highest photoelectric conversion efficiency.

FIG. 4 is a graph showing the thermal stability of PSCs fabricated using titanium dioxide doped with 1% Nb as a mesoporous layer in accordance with the present invention compared to PSCs fabricated using titanium dioxide undoped with Nb as a mesoporous layer. Compared with PSCs prepared by taking titanium dioxide which is not doped with Nb as a mesoporous layer, PSCs prepared by taking titanium dioxide which is doped with Nb as a mesoporous layer have higher thermal stability.

Fig. 5 is a graph comparing the uv stability of PSCs fabricated with titanium dioxide doped with 1% Nb as a mesoporous layer and PSCs fabricated with titanium dioxide undoped with Nb as a mesoporous layer according to the present invention. Compared with PSCs prepared by taking titanium dioxide not doped with Nb as a mesoporous layer, PSCs prepared by taking titanium dioxide doped with 1% of Nb as a mesoporous layer have higher ultraviolet stability.

FIG. 6 is a graph showing the comparison of photoelectric conversion efficiency of the PSCs prepared by calcining the mesoporous layer of 1% Nb-doped titanium dioxide at 500 ℃ for different time periods. As can be seen from the figure, the effect is best when the calcination is carried out for 30 min.

FIG. 7 is a graph showing the comparison of photoelectric conversion efficiency of PSCs prepared by calcining 1% Nb-doped titanium dioxide as mesoporous layer at different temperatures for 30 min. As can be seen from the figure, the effect is best at a calcination temperature of 500 ℃.

Wherein the reference numerals are as follows:

the preparation method comprises the following steps of 1-FTO glass substrate, 2-dense layer titanium dioxide, 3-mesoporous layer, 4-perovskite layer, 5-hole transport layer and 6-counter electrode.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples. The following examples are intended to illustrate the invention only and are not intended to limit the scope of the invention.