阅读说明：本技术 一种高稳定性铋碘杂化光吸收剂及其制备与应用 (High-stability bismuth-iodine hybrid light absorber and preparation and application thereof ) 是由 赵若愚 刘广宁 许让栋 韦天慧 牛鹏飞 李村成 于 2019-10-10 设计创作，主要内容包括：本发明公开了一种高稳定性铋碘杂化光吸收剂Me4ppi-BiI<Sub>4</Sub>的制备方法与应用。所述材料的结构式为Me4ppi-BiI<Sub>4</Sub>,式中的Me4ppi代表甲基化的4-苯基吡啶阳离子,该材料中的BiI<Sub>4</Sub>阴离子则是三价铋离子和碘离子配位形成的一维阴离子链。选择三氯化铋,4-苯基吡啶,甲醇,乙腈和氢碘酸为反应原料,合成获得了化合物Me4ppi-BiI<Sub>4</Sub>的单晶,该材料在在75%相对湿度和太阳光下可以分别至少承受35天和7天并保持优异的光电响应能力,且粉末衍射证明该化合物在两种条件下均保持了其相纯度。(The invention discloses a high-stability bismuth-iodine hybrid light absorber Me4ppi-BiI 4 The preparation method and the application thereof. The structural formula of the material is Me4ppi-BiI 4 Me4ppi in the formula represents methylated 4-phenylpyridine cation, BiI in the material 4 The anion is a one-dimensional anion chain formed by coordination of trivalent bismuth ions and iodide ions. Selecting bismuth trichloride, 4-phenylpyridine, methanol, acetonitrile and hydroiodic acid as reaction raw materials to synthesize and obtain a compound Me4ppi-BiI 4 The material can bear at least 35 days and 7 days under 75% relative humidity and sunlight respectively and maintain excellent photoelectric response capability, and powder diffraction proves that the compound maintains the phase purity under both conditions.)

1. High-stability bismuth-iodine hybrid light absorber Me4ppi-BiI₄In which Me4ppi is a methylated 4-phenylpyridine cation, which compound is monoclinic and crystallizes in P2₁The crystal has a structural characteristic that the crystal has a dark red color and a molecule containing 4-phenylpyridine cation with one unit positive charge and one dimension [ BiI ] in the molecule₄]^—The anion chain and the anions are formed by in-situ self-assembly, the cation is formed by 4 phenylpyridine in-situ N-methylation and carries a positive charge, and the anion is a one-dimensional anion chain formed by coordination of trivalent bismuth ions and iodide ions.

2. The bismuth-iodine hybrid light absorber Me4ppi-BiI as claimed in claim 1₄Is characterized in thatIn the following steps: weighing the mixture in a molar ratio of 0.5: 0.2: 1 BiCl₃Adding HI, methanol and acetonitrile into 4-phenylpyridine and KCl, and keeping the temperature at 120 ℃ for three days to obtain a deep red crystalline product which is a compound Me4ppi-BiI₄。

3. The bismuth-iodine hybrid light absorber Me4ppi-BiI as claimed in claim 1₄The use of (a), characterized in that: the material has strong environmental stability and high photoelectric response, and is used in the fields of photovoltaics and optical detection as a light absorbent.

Technical Field

The invention relates to the field of inorganic-organic hybrid materials, in particular to a high-stability bismuth-iodine hybrid light absorber Me4ppi-BiI₄In which Me4ppi = methylation, and their use4-phenylpyridine of (1).

Background

Over the past few years, lead-based organometallic halide light absorbers such as CH₃NH₃PbX₃Photovoltaic research of (X = Cl, I, Br) has become one of the hot topics of modern chemistry and material science. CH from Miyasaka and coworkers₃NH₃PbX₃After being incorporated as a sensitizer in a dye-sensitized solar cell, a huge leap from 3.8% to 24% in energy conversion efficiency of the lead-based organic metal halide solar cell was achieved over ten years. This dramatic performance improvement should be attributed to the sum of its various physical properties, including strong optical absorption, moderate band gap, high defect tolerance, low exciton confinement energy, and high carrier mobility, among others. Nevertheless, environmental stability (e.g., humidity stability and light stability) and heavy metal toxicity under actual work have become great obstacles limiting the commercial promotion thereof, and therefore, it is imperative to explore a "take the essence, discard" non-lead material as a substitute.

Wherein, the same main group metal Ge is adopted²⁺And Sn²⁺Substitute for Pb²⁺Is the most straightforward method, however, no matter Ge²⁺Or is Sn²⁺They are more easily oxidized in air to the tetravalent state of Ge⁴⁺And Sn⁴⁺But rather makes the stability worse. Another solution is to introduce an isoelectric substance to replace Pb²⁺E.g. Sb³⁺And Bi³⁺. Due to their 6s²6p⁰Electronic configuration and Pb²⁺Similarly, stronger light absorption and long carrier lifetime can therefore theoretically also be achieved. In comparison with Bi³⁺It seems to be a better choice, Bi is a non-toxic heavy metal only in the periodic Table of elements, is very friendly to the human body, some coordination complexes of bismuth have even been used in pharmaceuticals, and Bi is a neighboring ion in the periodic Table³⁺And Pb²⁺Have very similar ionic radii, which can lead to Bi³⁺More readily incorporated into the perovskite lattice. However, it cannot be shaped due to its higher oxidation state of +3Generic MAPbI₃On the contrary, the common vertex connecting structure of (1) is more inclined to form two BiXs₆0-dimensional Bi of coplanar connection₂X₉Structure, despite the current Bi₂X₉The light absorbent achieves 2-3% of energy conversion efficiency in the solar cell, but due to the problem of low carrier transmission efficiency inherent in the zero-dimensional structure, Bi is limited₂X₉Further development of type light absorbers. On the other hand, most of the organic components of the existing Bi — X light absorbers are hydrophilic amine type cations or aromatic cations with strong hydrophilicity, which is very disadvantageous for their humidity stability.

Disclosure of Invention

The invention aims to solve the problems of low carrier transmission efficiency and poor stability of the existing zero-dimensional bismuth-halogen-based light absorber, and adopts low-cost BiI₃And 4-phenylpyridine are used as raw materials, and hydrophobic alkyl cations are generated through an in-situ alkylation reaction, so that the bismuth-iodine hybrid light absorber which is one-dimensional chain and has excellent stability is synthesized.

The technical scheme of the invention comprises the following contents:

1. high-stability bismuth-iodine hybrid light absorber Me4ppi-BiI₄Me4ppi in the formula represents a methylated 4-phenylpyridine cation. The compound is monoclinic system, and is crystallized in P2₁The/n space group, unit cell parameters a = 7.69 angstrom, b = 19.94.64 angstrom, c = 13.04 angstrom, α =90 degrees, β = 100.59 degrees, γ =90 degrees. The crystal color of the material is deep red and shows an ionic organic-inorganic hybrid structure. The specific structure is characterized in that cations in the structure are 4-phenylpyridine cations with a unit positive charge, the cations are formed by N atom methylation in 4-phenylpyridine, and anions are [ BiI ] formed by coordination of trivalent bismuth ions and iodide ions₄]^—A one-dimensional anionic chain, which is used to balance the positive charge of the 4-phenylpyridine cation, making the whole structure electrically neutral; BiI is adopted as bismuth ions in an anion chain₆An octahedral coordination mode, wherein iodide ions are connected with adjacent bismuth ions in an end group coordination mode or a mu 2 bridging group coordination mode, and hydrogen bonds and coulomb interaction exist between cations and anions.

2. The method for preparing a bismuth-iodine hybrid light absorber according to item 1, characterized in that: weighing the mixture in a molar ratio of 0.5: 0.2: 1 BiCl₃Adding HI, methanol and acetonitrile into 4-phenylpyridine and KCl, screwing, heating in an oven at 120 deg.C for three days, cooling to room temperature to obtain deep red crystalline product Me4ppi-BiI₄。

3. Use of the bismuth-iodine hybrid light absorber of item 1, characterized in that: the material is used as a light absorber and has strong absorption in visible light and ultraviolet regions.

The invention has the advantages that the product has high stability, can bear 35 days and 7 days respectively at least under 75% relative humidity and solar illumination, and is superior to MA₃Bi₂I₉And has excellent photoelectric conversion properties, and is useful as a light absorbing agent.

Drawings

FIG. 1 shows a bismuth-iodine hybrid light absorber Me4ppi-BiI₄A block diagram of a single asymmetric unit. Symmetric codes are A2-x, 1-y, 1-z and B1-x, 1-y, 1-z..

FIG. 2 shows a bismuth-iodine hybrid light absorber Me4ppi-BiI₄The scan voltage range of the I-V curve of (1) is-5 to 5 volts, and the scan rate is 50 millivolts/sec.

FIG. 3 shows a bismuth-iodine hybrid light absorber Me4ppi-BiI₄The I-T curve tested under the constant bias voltage of 2 volts and the optical power density of 85 milliwatts per square centimeter can still maintain excellent photoresponse capability and cyclicity after the compound is placed for 35 days at the relative humidity of 75 percent and is irradiated by sunlight for seven days, thereby proving that the material has higher stability.

FIG. 4 shows a bismuth-iodine hybrid light absorber Me4ppi-BiI₄The powder diffraction patterns under various environments are completely consistent with the simulated diffraction results of single crystals.

FIG. 5 shows a bismuth-iodine hybrid light absorber Me4ppi-BiI₄The absorption spectrum of (2) shows that the compound has strong absorption in both ultraviolet and visible light regions.

Detailed Description

(1) Compound Me4ppi-BiI₄Synthesis of (2)

0.158 g of BiCl₃0.075 g of KCl and 0.031 g of 4-phenylpyridine are put into a 25 ml of polytetrafluoroethylene inner container of an inner-sleeved glass small bottle, 0.5 ml of HI, 5 ml of methanol and 2 ml of acetonitrile are added, then the polytetrafluoroethylene inner container is put into a stainless steel reaction kettle, the stainless steel reaction kettle is heated in a 120 ℃ oven after being screwed, the temperature is kept constant for three days, then the mixture is cooled to the room temperature, and red columnar crystals are obtained after treatment, namely the compound Me4ppi-BiI₄。

(2) Photoelectrochemical testing

5 mg of fully ground Me4ppi-BiI₄Dispersing the powder in 0.3 ml of ethanol, ball-milling for thirty minutes, uniformly mixing, then dripping 3.5 microliters of the dispersion liquid on an interdigital electrode with the size of 1 multiplied by 1 square centimeter, repeating five times, drying in vacuum at 40 ℃ for four hours to obtain a thin film photoelectrode, and carrying out timing potential scanning and linear volt-ampere scanning on the photoelectrode under a light source with the optical power density of 85 milliwatt/square centimeter. The linear voltammetric scan voltage range is-5-5 volts, the scan rate is 50 millivolts/second, the timed potential scan potential is 2 volts, and the shutter time is set to 5 seconds.