CN105742506A - Organic-inorganic hybrid photoelectrochemical anode electrode and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of photoelectrochemistry, and particularly relates to an organic-inorganic hybrid photoelectrochemical anode electrode and a preparation method thereof. The electrode comprises a back electrode, wherein the back electrode is provided with a silicon substrate; organic conjugated molecules are deposited on the silicon substrate; the insolubility and the stability of the organic conjugated molecules are improved by a coupling agent on the silicon substrate; and the coupling agent comprises any one or more of a silane coupling agent, a titanate coupling agent, an organic chromium complex coupling agent and a zirconium compound coupling agent. An organic conjugated molecule film on the electrode is relatively stable in water and not liable to fall off; and the performance of the electrode is improved.

Description

A kind of organic-inorganic hybrid photoelectrochemical anode electrode and preparation method thereof

technical field

The invention belongs to the technical field of photoelectrochemistry, and in particular relates to an organic-inorganic hybrid photoelectrochemical anode electrode and a preparation method thereof.

Background technique

In recent years, energy issues have increasingly become a major issue for the survival and development of human society. The use of new energy has become a necessary means to solve energy problems. Among them, photoelectrochemical water splitting has attracted extensive attention and research because it can effectively convert solar energy into chemical energy for storage. Silicon material is an ideal material for photovoltaic devices and optoelectronic devices because of its high-efficiency photoelectric conversion effect, carrier transport effect, mature process, and relatively low cost. At the same time, silicon material is also an important photoelectrochemical electrode material. Higher efficiency can be achieved by depositing noble metals such as platinum, ruthenium, and iridium on silicon materials, but its cost is high, and due to the limited earth reserves of noble metal elements, it is not suitable for mass production of photoelectrochemical electrodes.

By depositing organic conjugated molecules on the surface of silicon materials, photoelectrochemical electrodes can be prepared, avoiding the use of noble metals, and realizing the photolysis of water. Organic conjugated materials can be polymers such as polythiophene (PTH), polypyrrole (PPY), polyaniline (PANI), polyacetylene (PA), polyparaphenylene vinylene (PPV), etc., because they are used in many reactions Excellent catalytic performance, can be prepared by solution spin coating method, high conductivity, low cost and other advantages, it has certain application prospects in organo-silicon photoelectrochemical electrodes, but because its film is easily destroyed and unstable in water, etc. The reason is that in order to prevent the film from falling off and improve its stability, it must be treated to a certain extent.

In view of the above-mentioned defects, the designer is actively researching and innovating in order to create an organic-inorganic hybrid photoelectrochemical anode electrode and its preparation method, so that it has more industrial application value.

Contents of the invention

In order to solve the above-mentioned technical problems, the object of the present invention is to provide an organic-inorganic hybrid photoelectrochemical anode electrode and its preparation method. The organic conjugated molecular film on the electrode is relatively stable in water, not easy to fall off, and improves the performance of the electrode.

The present invention proposes an organic-inorganic hybrid photoelectrochemical anode electrode, including a back electrode, on which there is a silicon substrate, on which organic conjugated molecules are deposited, wherein, on the silicon substrate, by using a couple The coupling agent improves the insolubility and stability of organic conjugated molecules, and the coupling agent includes any one of silane coupling agent, titanate coupling agent, organic chromium complex coupling agent, and zirconium compound coupling agent or more.

Further, the silane coupling agent includes γ-(2,3-glycidoxy)propyltrimethoxysilane, aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-Glycidoxypropyltrimethoxysilane, γ-Methacryloxypropyltrimethoxysilane, γ-Mercaptopropyltrimethoxysilane, Acrylpropyltrimethoxysilane, γ- Chloropropyltriethoxysilane, Vinyltriethoxysilane, Vinyltrimethoxysilane, Vinyltris(β-methoxyethoxy)silane, N-β-(Aminoethyl)-γ- Aminopropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-chloropropyltriethoxysilane, vinyltri-tert-butylperoxysilane, vinyltrichlorosilane Any one or more of silane, vinyltrimethoxysilane, phenylaminopropyltrimethoxysilane, and γ-isocyanatepropyltriethoxysilane.

Further, the titanate coupling agent includes isopropyl tris (dioctyl pyrophosphate acyloxy) titanate, isopropyl tris (dioctyl phosphate acyloxy) titanate, isopropyl Any one of dioleic acid acyloxy (dioctyl phosphate acyloxy) titanate, monoalkoxy unsaturated fatty acid titanate, bis (dioctyloxypyrophosphate) ethylene titanate one or more species.

Further, the organic conjugated molecule includes any one or more of polythiophene, polypyrrole, polyaniline, polyacetylene, polyphenylene vinylene, polyalkylene oxide, self-doped or undoped high molecular compound.

Further, the polythiophene includes poly(3,4-ethylenedioxythiophene), (3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), (3,4-ethylenedioxythiophene) Dioxythiophene)-any one or more of polyethylene glycol, poly-3-hexylthiophene, and poly-3-methylthiophene.

Further, the organic conjugated molecule is (3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid).

Further, the silicon substrate is a single crystal flat bottom silicon or a silicon substrate with a surface structure.

Further, the back electrode is a titanium electrode.

The present invention also proposes a method for preparing an organic-inorganic hybrid photoelectrochemical anode electrode, comprising the following steps:

(1) pretreatment of silicon substrate;

(2) preparing a solution of organic conjugated molecules doped with a coupling agent;

(3) Depositing the organic conjugated molecule solution in step (2) on the silicon substrate by spin coating, and performing annealing treatment;

(4) Depositing a back electrode on the back of the silicon substrate by means of electron beam deposition or vacuum thermal evaporation.

By means of the above scheme, the present invention has at least the following advantages: In the present invention, a coupling agent is introduced as an additive, which is doped into the organic conjugated material, and the organic conjugated material is deposited on the silicon substrate by spin coating to obtain an electrode , the coupling agent can improve the contact force between the organic conjugated molecular film and the silicon substrate, thereby improving the quality of the formed Schottky junction. In addition, the hydrolysis of the coupling agent generates groups attached to the surface of the silicon substrate, which can It plays a passivation role, effectively reduces the surface recombination rate of solar cells, and is more conducive to the separation and collection of electrons.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below.

Description of drawings

Fig. 1 is the structural representation of organic-inorganic hybrid photoelectrochemical anode electrode;

Fig. 2 is the linear sweep voltammetry characteristic curve of organic-inorganic hybrid photoelectrochemical anode electrode in embodiment 1;

Fig. 3 is the linear sweep voltammetry characteristic curve of the organic-inorganic hybrid photoelectrochemical anode electrode in Example 2.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

Referring to Figure 1, the 0.05-0.1Ωcm ^-1 flat-bottomed silicon substrate was ultrasonically cleaned with acetone, ethanol, and deionized water for 20 minutes. A mixed solution of AgNO ₃ and 4.8mol/L HF etched the silicon wafer for 10 minutes, rinsed with deionized water and placed in concentrated nitric acid to remove silver, took it out, rinsed and dried it, placed it in the HF solution to remove the silicon oxide layer on the surface, and placed it React in a tetramethylammonium hydroxide (TMAH) solution with a volume concentration of 1% for 30 seconds to prepare a silicon nanowire substrate. Add 5% and 1% dimethyl sulfoxide (DMSO) and Triton (polyethylene glycol octylphenyl ether) to (3,4-ethylenedioxythiophene)-poly( Styrene sulfonic acid) (PEDOT:PSS) in aqueous solution, and add the silane coupling agent γ-(2,3-epoxypropoxy)propyltrimethoxysilane (GOPS) with a volume percentage of 0.3% , stir well. Spin coating method is used to deposit PEDOT:PSS on the surface of silicon nanowire substrate, the rotation speed is 3000RPM, and the time is 1min. In other embodiments, methods such as spraying, printing, gas phase polymerization, electrochemical polymerization or electrospinning can also be used. The organic conjugated molecules are deposited with a deposition thickness of 20-200 nm, and in this embodiment, the deposition thickness is 100 nm. Then, after annealing at 125° C. for 10 minutes, electron beam deposition is used to deposit 10-300 nm of Ti on the back surface of the silicon nanowire substrate. In this embodiment, the thickness of Ti is 30 nm.

Under the irradiation of a 100mW/cm ² AM1.5 solar simulator, the above-mentioned photoelectrochemical anode electrode was placed in an electrolytic cell, and it was tested using a three-electrode system. The counter electrode was a platinum electrode, and the reference electrode was a saturated Ag electrode. /AgCl electrode, the electrolyte solution is HI solution, in other embodiments, the counter electrode can also be a carbon electrode, other electrochemical electrodes or other corresponding photoelectrochemical electrodes, and the electrolyte solution can be HBr solution. The measured electrode linear sweep volt-ampere characteristic curve is shown in Figure 2. Devices prepared by the method described above have the following characteristics:

(1) The polarizing potential of the electrode is -0.18V (relative to the standard hydrogen electrode), the photovoltage is 650mV, and the current density at the potential of 0 (relative to the standard hydrogen electrode) is 24.7mA/cm ² .

(2) The hydrogen production efficiency of the electrode is ~11.1%.

Example 2

Referring to Figure 2, the 0.05-0.1Ωcm ^-1 flat-bottomed silicon was ultrasonically cleaned with acetone, ethanol, and deionized water for 20 minutes. After drying with an inert gas, it was treated with a mixed solution of concentrated sulfuric acid and hydrogen peroxide at 60°C for 30 minutes. silicon oxide layer. Add 5% and 1% dimethyl sulfoxide (DMSO) and Triton to (3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) aqueous solution respectively , and add 0.3% by volume of silane coupling agent γ-aminopropyltriethoxysilane, and stir evenly. Deposit PEDOT:PSS on the surface of the flat-bottom silicon substrate by spin coating method, the rotation speed is 3000RPM, and the time is 1min. In other embodiments, it can also be deposited by spraying, printing, gas phase polymerization, electrochemical polymerization or electrospinning. The organic conjugated molecules are deposited in a thickness of 20-200 nm, and in this embodiment, the deposition thickness is 100 nm. Then, after annealing at 125° C. for 10 minutes, electron beam deposition is used to deposit 10-300 nm of Ti on the back of the flat-bottomed silicon substrate. In this embodiment, the thickness of Ti is 30 nm.

Under the irradiation of a 100mW/cm ² AM1.5 solar simulator, the above-mentioned photoelectrochemical anode was placed in an electrolytic cell, and it was tested using a three-electrode system. The counter electrode was a platinum electrode, and the reference electrode was a saturated Ag/ For the AgCl electrode, the electrolyte solution is HI solution. In other embodiments, the counter electrode can also be a carbon electrode, other electrochemical electrodes or other corresponding photoelectrochemical electrodes, and the electrolyte solution can be HBr solution. The measured electrode linear sweep volt-ampere characteristic curve is shown in Figure 3, and the device made by the above method has the following characteristics:

(1) The polarizing potential of the electrode is -0.17V (relative to the standard hydrogen electrode), the photovoltage is 640mV, and the saturation current density is 17.0mA/cm ² .

(2) The hydrogen production efficiency of the electrode is ~7.7%.

Example 3

A flat-bottomed silicon substrate with a resistance value of 1-10Ωcm ^-1 was ultrasonically cleaned with acetone, ethanol, and deionized water for 20 minutes in sequence. After drying with an inert gas, it was treated with a mixed solution of concentrated sulfuric acid and hydrogen peroxide at 60°C for 30 minutes, and then treated with 0.2mol/L AgNO ₃ Etch the silicon wafer with a mixed solution of 4.8mol/L HF for 10 minutes, rinse with deionized water and put it in concentrated nitric acid to remove silver, take it out, rinse and dry it, place it in the HF solution to remove the silicon oxide layer on the surface, and place it at a volume concentration react in 1% tetramethylammonium hydroxide (TMAH) solution for 30 seconds to prepare the silicon nanowire substrate. The polyaniline solution was dissolved in dimethyl sulfoxide to prepare a 10 mg/ml solution, and a titanate coupling agent isopropyl tris(dioctyl pyrophosphate acyloxy) was added with a volume percentage of 0.5% ) titanate, stir evenly. Polyaniline is deposited on the surface of the silicon nanowire substrate by spin coating at a speed of 2000 RPM for 1 min. In other embodiments, it can also be deposited by spraying, printing, gas phase polymerization, electrochemical polymerization or electrospinning. The organic conjugated molecules are deposited in a thickness of 20-200nm, and in this embodiment, the deposition thickness is 80nm. Then, after annealing at 125° C. for 10 minutes, electron beam deposition is used to deposit 10-300 nm of Al on the back surface of the silicon nanowire substrate. In this embodiment, the thickness of Al is 200 nm. The working electrolyte solution of the electrode can be H ₂ SO ₄ , HI, HBr, HCl and other solutions.

Example 4

The 0.5-1Ωcm ^-1 flat-bottomed silicon was ultrasonically cleaned with acetone, ethanol, and deionized water for 20 minutes in sequence. After drying with an inert gas, it was treated with a mixed solution of concentrated sulfuric acid and hydrogen peroxide at 60°C for 30 minutes, and the silicon oxide layer on the surface was removed in HF solution. Add 1% isopropyl tris(dioctyl phosphate acyloxy) titanate by volume to the nitromethane solution of PEDOT-PEG, and stir evenly. Deposit PEDOT-PEG on the surface of the flat-bottom silicon substrate by spin-coating at a speed of 4000 RPM for 1 min. In other embodiments, methods such as spraying, printing, gas-phase polymerization, electrochemical polymerization, or electrospinning can also be used to deposit PEDOT-PEG. The organic conjugated molecules are deposited in a thickness of 20-200 nm, and in this embodiment, the deposition thickness is 30 nm. Then, after annealing at 125° C. for 10 minutes, electron beam deposition is used to deposit 10-300 nm of Ag on the back of the flat-bottomed silicon substrate. In this embodiment, the thickness of Ag is 30 nm.

The working electrolyte solution of the electrode can be H ₂ SO ₄ , NaOH, H ₃ PO ₄ , LiBr and other solutions.

In summary, the present invention introduces a coupling agent as an additive, dopes it into an organic conjugated molecule, and forms an electrode on a silicon substrate by a solution processing method such as spin coating, spray coating, doctor blade coating or printing, The silicon substrate can be single crystal silicon, polycrystalline silicon or amorphous silicon, which can realize efficient and stable photoelectrochemical reaction in electrolyte solution. The organic conjugated catalytic material that the present invention adopts has polythiophene (PTH), polypyrrole (PPY), polyaniline (PANI), polyacetylene (PA), polyparaphenylene vinylene (PPV) etc. as backbone polymer, and organic Materials such as conjugated small molecules. The silane coupling agent is hydrolyzed under acidic or alkaline conditions, and the -OH bond formed by hydrolysis at one end interacts with organic conjugated molecules, and the other end is hydrolyzed to form a Si-O bond, which is connected to the Si-H bond and Si -OH reaction, under annealing conditions, a molecule of water is removed to form Si-O-Si, which becomes a dense network, thereby improving the contact force between the organic conjugated molecular film and the silicon wafer, thereby improving the formed Schottky junction. quality, effectively preventing the film from falling off in the aqueous electrolyte. The silane coupling agent is hydrolyzed to form a group attached to the surface of the silicon wafer, which can passivate the silicon wafer, effectively reduce the surface recombination rate of the solar cell, and is more conducive to the separation and collection of electrons.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can be made without departing from the technical principle of the present invention. and modifications, these improvements and modifications should also be considered as the protection scope of the present invention.

Claims (9)

1. An organic-inorganic hybridization photoelectrochemical anode electrode is characterized in that: comprise back electrode, on described back electrode, silicon base is arranged, on described silicon base, organic conjugated molecule is deposited, wherein, on silicon base, pass Use coupling agents to improve the insolubility and stability of organic conjugated molecules, and the coupling agents include any of silane coupling agents, titanate coupling agents, organic chromium complex coupling agents, and zirconium compound coupling agents. one or more. 2. The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 1, characterized in that: the silane coupling agent comprises γ-(2,3-glycidoxy) propyltrimethoxysilane, Aminopropyltriethoxysilane, γ-Aminopropyltriethoxysilane, γ-Glycidoxypropyltrimethoxysilane, γ-Methacryloxypropyltrimethoxysilane, γ -Mercaptopropyltrimethoxysilane, Acrylpropyltrimethoxysilane, γ-Chloropropyltriethoxysilane, Vinyltriethoxysilane, Vinyltrimethoxysilane, Vinyltri(β- Methoxyethoxy)silane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-chloropropyl trimethoxysilane Ethoxysilane, vinyl tri-tert-butyl peroxysilane, vinyl trichlorosilane, vinyl trimethoxysilane, phenylaminopropyl trimethoxysilane, γ-isocyanate propyl triethoxysilane any one or more of. 3. The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 1, characterized in that: the titanate coupling agent comprises isopropyl tris (dioctyl pyrophosphate acyloxy) titanate, Isopropyl tris (dioctyl phosphate acyloxy) titanate, isopropyl dioleic acid acyloxy (dioctyl phosphate acyloxy) titanate, monoalkoxy unsaturated fatty acid titanate, Any one or more of bis(dioctyloxypyrophosphate)ethylene titanates. 4. The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 1, characterized in that: said organic conjugated molecules include polythiophene, polypyrrole, polyaniline, polyacetylene, polyparaphenylene vinylene, polyepoxy Any one or more of alkanes, self-doped or non-doped polymer compounds. 5. The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 4, characterized in that: said polythiophene comprises poly(3,4-ethylenedioxythiophene), (3,4-ethylenedioxythiophene), (3,4-ethylenedioxythiophene) Any one or more of poly(oxythiophene)-poly(styrenesulfonic acid), (3,4-ethylenedioxythiophene)-polyethylene glycol, poly-3-hexylthiophene, poly-3-methylthiophene kind. 6. The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 5, characterized in that: the organic conjugated molecule is (3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) . 7 . The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 1 , wherein the silicon substrate is a single crystal flat bottom silicon or a silicon substrate with a surface structure. 8. The organic-inorganic hybrid photoelectrochemical anode electrode according to claim 1, characterized in that: the back electrode is a titanium electrode. 9. according to the preparation method of organic-inorganic hybrid photoelectrochemical anode electrode described in any one of claim 1 to 8, it is characterized in that: comprise the following steps: (1) pretreatment of silicon substrate; (2) preparing a solution of organic conjugated molecules doped with a coupling agent; (3) Depositing the organic conjugated molecule solution in step (2) on the silicon substrate by spin coating, and performing annealing treatment; (4) Depositing a back electrode on the back of the silicon substrate by means of electron beam deposition or vacuum thermal evaporation.