JPS5944773A - Photoresponsive high-polymer electrolyte film - Google Patents

Abstract

PURPOSE:To give simply excellent photoresponsiveness to a film by making a polyanion type high-polymer electrolyte film to hold a tris(polypyridyl) metal (II) complex. CONSTITUTION:A polyanion type high-polymer electrolyte film such as naphion is made to hold a tris(polypyridyl) metal (II) complex belonging to the periodic law table VIII family. A photocurrent is remarkably increased when a proper oxidation-reduction reagent capable of electron mobile reaction is made to be melted or to coexist in said film during said metal (II) complex is in the excited condition.

Description

Detailed Description of the Invention 10 Background of the Invention [Technical Field] The present invention relates to a photoresponsive film, and more specifically, a tris(polypyridyl) metal complex in a polyanionic polymer film. The present invention relates to a photoresponsive film containing and retaining.

[Prior art and problems]

Most of the materials used for conventional photoconversion elements are metals and semiconductors that utilize optical physical processes. However, if we can fully utilize the chemical reaction of the photoexcited state of the compound, that is, if we can design all the conditions such that the compound that absorbs light and becomes excited state causes i°C charge separation, then based on the new theory, <
yt, it should be possible to use it as a conversion element. In the present invention, a photoconversion element based on such a new idea is manufactured by using a polymer electrolyte membrane. The realization of photoresponsive films based on such new principles has extremely high utility value as optical sensors, photovoltaic cells, water electrolytic membranes that rely on light, semiconductor devices, and completely new types of photodiodes.

It is well known that general (tris(polypyridyl) metal) loss complexes (hereinafter referred to as rM (ppy): +J) exhibit excellent photoreactivity in liquid.
Electrons are transferred from the photoexcited state to various Rn receptors, but because the reverse electron transfer reaction is fast, no photoresponse is observed at the electrode even if the electrode is completely immersed in a solution containing both.

However, the membrane obtained by supporting M (my): When the thin film is adhered and held, the excited state complex MCpp
tt)","It has become possible to conduct an electron transfer reaction on the surface of the thin film, and as a result, it has been found that it is possible to develop a photoresponsive function in a polymer electrolyte membrane (which originally does not have a photoresponsive mechanism). The invention was completed based on the above findings.

■1 Purpose of the Invention Therefore, the purpose of the present invention is to retain MCppy)'g"f, which exhibits excellent photoreactivity in solution, in a polymer film, thereby imparting photoresponsivity to the film. be.

The object of the present invention is to further provide photoreactive M(7+7ty
) To provide a photoresponsive polymer electrolyte membrane in which a thin film of an electrically conductive substance is adhered and retained on the surface of a polymer electrolyte membrane containing 0.40, in which a polymer membrane and a thin conductor are integrated. It is.

Specific Description of the Invention The polypyridyl ligand of A/(ppv)a+ used in the present invention includes, for example, 2,2'-bipyridine (hereinafter referred to as Cbpv), O-phenanthroline (hereinafter referred to as (
You can list all the words such as phen). In general, polymer compounds having polypyridyl groups in their molecules can also be used in the present invention.

Examples of such polymer compounds include the following.

One is a polypyridyl compound that has a vinyl foundation molecule,
For example, 4-vinyl-2,2'-bipyridyl, 4-methyl-4'-vinyl-2,2'-bipyridyl, 4-vinyl-〇-phenanthroline, 4-methyl-7-pinyl-O
- Polymer compounds obtained by polymerizing phenanthroline or the like alone, or polymer compounds obtained by copolymerizing with other vinyl compounds in any proportion are exemplified. Another example is a polypyridyl-containing polymer compound synthesized by reacting a polymer compound with a polypyridyl compound.

An example of this is polystyrene in which a polypyridyl group is introduced into the aromatic ring by brominating the aromatic nucleus of polystyrene (this is lithiated), and then a total reaction of the polypyridyl compound (this is done. Examples include polymer compounds obtained by reacting -2,2'-bipyridyl with all-polyvinyl alcohol, and polymer compounds obtained by reacting poly(4-vinylpyridine) with γ-picoline.These polypyridyl groups A sieve molecule metal complex synthesized by the reaction of a polymer compound containing M(ppy)i+ with M(ppy)i+ can be used in the present invention.
The middle metals include iron, cobalt, nickel, ruthenium, rhodium, palladium, which belongs to Ichihara of the periodic table.
Examples include osmium, iridium, and platinum. Usually, these extra salts, such as chloride JP sulfate, are reacted with the ligand in a suitable solvent to obtain the entire complex.

By using such a metal complex while holding it in a polyanionic polymer film, it is possible to impart photoresponsiveness to the film.

If an appropriate redox agent is dissolved or coexists in the liquid or film, the photocurrent increases significantly. The above-mentioned redox reagent means a reagent capable of electrodynamic reaction with the excited state of the tris(polypyridyl) metal complex, and includes an electron-accepting redox reagent and an electron-donating redox reagent. Electron-accepting redox reagents that accept electrons from the excited state of the complex include viologens, cupric salts, ferric salts, cyanide of iron, copper, nickel, cobalt, molybdenum, chromium, ruthenium, platinum, etc. Examples include complexes, ammine complexes, thiorad complexes, complexes with organic coordination compounds, quinones and derivatives thereof, tetracyanoquinodimethane, nitrobenzene and derivatives thereof. Among these, viologens include dimethyl viologen, diethyl viologen, etc., as well as dialkyl viologens having 20 or fewer carbon atoms, viologen derivatives such as polymeric viologens bonded to polymeric compounds, and polyxylyl viologens. Specific examples of donating redox reagents include aromatic amines, hydroquinone, and derivatives thereof.

The polyanion-type foveolar molecule TA membrane used in the present invention is Nafion (trade name: Heavy membrane No. 1 manufactured by DuPont).
20.125.315.415, etc.), strong anionic fluororesins such as Semireon (trade name: manufactured by Asahi Glass Co., Ltd.), and poly(methyl methacrylate).

As the conductor and semiconductor that coats the surface of the polymer electrolyte membrane in the form of a thin film, platinum, gold, ruthenium oxide, titanium oxide, zinc oxide, tin oxide, indium oxide, carbon, etc. are used. To prepare the entire 7114(ppy)3-containing polymer film for the polyanion-type foveal molecular film klffi, first prepare a stock solution containing MCppy)3 complex gold.
Soak the polymer membrane for a sufficient amount of time. As a result, MCp
py) Yu+ can be inserted and fixed into the membrane (N, Oyama &
F, ,C,Anson+ J,Electroche
m, 5oc-+ 127.247 (1980)). By the same method◆, electron-accepting redox reagents can also be retained in the polymer electrolyte membrane. Immersing the polymer membrane
) 3 Solution solvents include water, dimethyl sulfoxide (CDMSO), dimethyl formamide (DMF), etc. The membrane itself tends to contain solvents, and MCppy ) 'g+
A medium that dissolves the electron-accepting redox reagent and the electron-accepting redox reagent is preferred.

When immersed in Nafion (membrane no. 125) kl for 0 min in an aqueous solution of 10mM Ru (bpy), the membrane turned orange, and as determined by spectrophotometry,
In addition, a polymer metal complex (4) synthesized by the reaction of a polypyridyl-containing polymer compound and IvfCppv)7 (C Patent, Application No. 1985-39859) containing a ruthenium complex of more than mM was retained in the membrane. If the complex is DMSO
, DM'F, so this solvent was used as the entire medium.
When the above Nafion'fc was immersed in a stock solvent of OmATm degrees (concentration per ruthenium unit), the same amount of ruthenium complex could be retained in the film. The ruthenium-containing complex Nafion membrane prepared by the above method was immersed in pure water, and the retention stability of the ruthenium complex in the membrane was investigated.
+Reduction due to elimination of complex monomers and polymers (1%
Within the experimental error, almost no particles were observed and the film was extremely stably retained in the film. In dry conditions, the ruthenium complex was retained extremely stably in both the internally prepared membranes and the membranes.

The same study as above was also conducted with electron-accepting redox reagents. First, 10 mA (Nafion membrane number 125 was immersed in methyl viologen aqueous solution for 10 minutes, then washed with water for 50 m
It was immersed in a solution containing MNα2St04 to convert all the methyl viologen retained in the Nafion membrane into monocation radicals, and the concentration of methyl viologen fixed in the membrane was measured by spectrophotometry, and it was found to be 1.0 M or more. . The experiment was conducted under Aτ airflow. Also, polymeric methyl viologens such as polyxylyl viologen and CB (dissolved in a 1:1 weight ratio solvent of methyl alcohol and DMSO)
Even if you use or its derivatives, C horn.

As expected, the compound could be inserted and retained in Nafion ++C River. j] The retention stability of the reagent under aqueous solution immersion conditions in Furnace II was good for both 7-mer and polymer. The distribution in 1 was not uniform compared to monomeric viologen.

When Nafion (membrane number 125) was immersed in an aqueous solution of LOmAI Fe(phen):+ for 30 minutes, the membrane turned reddish-orange, and as measured by spectrophotometry, il was 2.
More than mAl of iron complex was retained in the membrane. 1. As a result of immersing the fabricated iron-containing complex Nafion membrane in pure water and stabilizing the retention of the complex in the membrane, the reduction due to desorption of the complex by 6'C after 24 hours of immersion was 80 ~ 90%, and the complex is stably retained in the membrane J9. There wasn't.

A thin film of gas-conducting or semi-conducting material can be deposited on the side surface of the polymer membrane either before or after the metal complex or redox agent is inserted into the high force membrane. For example, a thin metal film is previously deposited on one side of the polymer membrane surface by vacuum deposition, electroless plating, etc., and a metal complex is inserted into the hindlimb membrane.

Alternatively, after inserting a metal complex or the like, the side surface of the membrane is coated. (For example, in the case of Ru02N film production, the film is
When coating with 1LO4, the film surface substance is oxidized Jl
, Ru0z thin film is deposited. In general, the thickness of a thin film is
Considering the light transmittance, adhesion to the polymer film, conductivity, mechanical strength, expansion coefficient, etc., a good result of about 6 give.

During light irradiation, if fine particles of metal are dispersed and held in a film holding a metal complex or the redox reagent, it becomes possible to change or increase the photoresponsiveness. Metal fine particles can be retained on the film by the following method. For example, after fully immersing a polymer electrolyte membrane fPtCl knee or PttC bow in a solution, one side of the membrane is A'a,
B11* C% Kaisho 55-38934] and N2114
The membrane is immersed in an alkaline solution containing 1) t and Pd metal can be precipitated on the bottom surface and inside of the membrane by the reduction reaction of metal 4-one. .

The photo-functionalized film thus prepared (hereinafter referred to as 1) was connected to the counter electrode with a conductive wire, and the photofunctionalized film (hereinafter referred to as 1) was connected to the counter electrode with a conductive wire, and the photofunctionalized film (hereinafter referred to as 1) was connected to the counter electrode with a conductive wire, and the film was washed with water or a polar organic medium, such as alcohol, in which the supporting electrolytic strip was dissolved.
acetonitrile, detrahydrofuran, sioxin,
I) MF, 11 M I) When immersed in a solution such as A and irradiated with light to the working N electrode, a photocurrent is observed. When a polar organic medium is used, halogenated tetraalkylammonium salts, alkali metal salts of organic acids, etc. are used as the support material.

As a light source for irradiating the working electrode, for example,
Lamps, fluorescent lamps, tomoe/senonranno, ri/kusuden halogen lamps, sunlight, etc.''1 stone.

The response mechanism of the photoresponsive film of the present invention is explained as follows. .

MCppy was retained in the polymer electrolyte membrane),
generates M(ppy)3 under light irradiation, and when an appropriate electron-accepting compound (hereinafter abbreviated as 1kawa) coexists, charge transfer occurs, and A, 1(7
) TIJ) Generates "3" and A-.

Even if the normal reaction system coexists in a solution, the reverse reaction caused by ) is extremely fast, so no photoresponse is observed in this solution system using a normal electrode. However, when the reaction system is held in a polymer electrolyte membrane and a conductive thin film is attached for observing and measuring the photocurrent, the electron transfer reaction with the conductor occurs due to the difference in the dominant reaction near the conductor surface. occurs, and cathode photocurrent and anodic photocurrent are observed. In the above reaction mode, when there is a conductive thin film on the left side, the anode photocurrent #J''-1 is observed, and the resulting photocurrent is approximately 2 On the other hand, at the anode, the flow ζ is almost unaffected. (r>py)",'
This is thought to be because the amount of λ accumulated near the thin film increases, which has an advantageous effect on the electrode reaction.

When fine particles of metal such as platinum are retained in the above-mentioned photoresponsive film, the cathode photocurrent, ano-I/light gravity, and current are both about 10
The doubling of 1, i'+ can be considered to be due to the increase in the effective electrode area and the reaction promoting effect of the holding metal.

Generally, the temperature conditions for obtaining photoresponsiveness are selected from the range of about 0° C. to 80° C., but usually room temperature is sufficient. Lid LE of the present invention
,, The responsive polymer electrolyte membrane has extremely high industrial value because it can easily impart photoresponsiveness to polymer membranes that are not originally photoresponsive1.The photofunctionalized membrane of the present invention It is extremely valuable in applications such as sensors, light weight 4W5, light-based water surface layer film semiconductor devices, and use as a completely new type of photodiode. The present invention will be explained in more detail with reference to Examples below.

Example 1 Cuff 1/(membrane number 125) was washed with 1.0M perchloric acid. Next, it was boiled in a 1.0&#αOH aqueous solution for about 1 hour, and then thoroughly washed with water. This film is Ru (bpv) 7.
& When immersed in an aqueous solution, the ruthenium complex is retained in the Naphimeno membrane.

After washing this membrane with water and drying, one surface of the membrane is coated with Rub< and coated with a Ru0z thin film. This membrane, which was in contact with a platinum wire, was heated with 10rr+Jf methylviologe/and C
It was immersed in an aqueous solution of pJll containing 02M of F3CO()Na, and using a platinum mesh as a counter electrode and a salt-saturated calomel electrode (hereinafter abbreviated as 'E') as a reference electrode, at room temperature, from 500 W xeno/lamp. The light of RuO
2 When irradiated from opposite sides of the thin film, -0.3 volts vs. 5S
A cathodic photocurrent of approximately 10 μA/cdl was generated at the potential of CH. Approximately 160 at a potential of +0.8 volts vs. 5SCE
An anode photocurrent of μA/art was generated. The experiment was conducted under an argon atmosphere.

Example Z The ruthenium-containing complex polymer solution membrane specially produced in Example 1 was treated with methyl viologen (1,1'-dimethyl-4,4'-dipyridine dichloride, hereinafter abbreviated as IMV J and #') 1
0 mM for 10 minutes. After washing with water, it was dried and coated with an RtLO2 thin film as described in Section 2.

When this film was immersed in an aqueous H7 solution containing 0.2 M of CP'3COONα and irradiated with light from a 500 Watt xenon lamp from the opposite side of the Ru02 thin film at room temperature, -0,
Approximately 15 μA/1 nfl at a potential of 3 volts vs. 5.5 CE
Cathode photocurrent of +0.8 volts vs. S S C' E
An anodic photocurrent of approximately 160 μA/ctt4 was generated.

The experiment was conducted under an argon atmosphere. A similar experiment,
Oxygen saturation II (1,2+I/ (,1"3COOA'
When the aqueous solution was 71 V, the Kan-1.

Examples & A Nafion membrane cleaned as in Example 1 is placed at the boundary of two chambers containing the heterovolume solution. One room has 20mA/
Pour the 112PtC16 aqueous solution, and add 0.5 to the remaining one.
Add an alkaline aqueous solution of M Na and BH4.1. 3,
After several minutes at room temperature, platinum begins to precipitate onto the side of the Nafion membrane containing the H4FtC16 solution.

After leaving this state for about 1 hour, the membrane was thoroughly washed with water.

Next, this Il* is treated in the same manner as in Example 2, and Ru(b7NI)"3+ and AlF2 are retained in this film. Next, the other film 111 on which platinum is not precipitated is Then, with Ru O4: T-tain, RtL(
Deposit J2 thin film. A lead was taken with a platinum wire as the Rqb O2 thin film electrode. Q, 2J/ (1' FsCOON a (F/7
When the platinum thin film is immersed in an aqueous solution of 7) and irradiated with light from a 500 xenon lamp at room temperature, -0,
Cathode photocurrent of 0.1 mA/crlr at potential of 3V vs. 5SCE, +0.8V vs. S, L5mA at 5CE
An anode photocurrent of /cy/i was generated3, and the experiments were performed under an argon atmosphere. When a similar experiment was performed under an oxygen atmosphere, the cathode photocurrent increased approximately twice.

Example 4 A Nafion membrane cleaned in the same manner as in Example 1 was treated with LOmMF.
The film is immersed in a solution containing e(phen)3 for 30 minutes to retain the iron complex in the film. Next, MV2+ is maintained by the same handling as in Example 2. The photoresponsiveness of the II film thus prepared was observed in the same manner as in Example 2. - Cathode photocurrent of about 3 μA/- at potential of 0.3 volts versus 5SCE, about 20 μA at +0.8 volts versus 5SCE
An anode photocurrent of /d is observed, +' also. The experiment was conducted under an argon atmosphere.

Examples & Nafion membranes washed in the same manner as in Example 1 were treated with 10mM (
It was immersed for about 1 hour in a DMSO solution of a ruthenium polymer complex of the formula (4) containing (ruthenium unit concentration). After washing this membrane with pure DMSO, it was immersed in an aqueous solution of polyxylyl viologen containing 10 m# (viologen unit concentration) for about 1 hour to produce a ruthenium-containing complex polymer and violoken polymer polymer electrolyte membrane. An experiment regarding this hip response was conducted in the same manner as in Example 2, and as a result, a cathode photocurrent of about 5 μA/cd at -0, 3 volts vs. 5 SCE,
At +0.8 volts vs. 5SCE an anode photocurrent of approximately 50 μA/e, 71, was produced.

Example 0 An experiment similar to Example 5 was conducted using a membrane in which the viologen polymer of formula (B) was retained in the Nafion membrane instead of polyxylyl viologen. In this case, a 1:1 (weight ratio) mixed solvent of methyl alcohol and DMSO was used to prepare the viologen polymer solution. When irradiated with light in the same way, -0, 3 volts; tJ, 5 scE, approximately 3 μA
Cathode photocurrent in /ca, 5.5 vs. 0.8 volts
At 6E, an anode photocurrent of approximately 20 μA/s occurred.

Example 7: A white thin film of about 100A (light transmittance 45%) was prepared using the water method using a piece of Nafion (film number 120) (111j).
A ruthenium complex and methyl biologe were prepared on the surface (-) by the same method as in Examples 1 and 2 to hold the ruthenium complex and methyl biologe in the film.Example 1 When irradiated with light in the same manner as above, the potential of -0.3 volts versus 5SCE is approximately 0.5
The cathode photocurrent of ~lμA/- is generated, +9.3 Holt vs.
An anode photocurrent of &.

Patent attorney Ryoji Kawase'', 1 373-

Claims (1)

[Scope of Claims] (1) A photoresponsive polymer electrolyte membrane characterized by retaining a tris(polypyridyl) metal (II) complex of Group I metal of the periodic table in a polyanionic polymer electrolyte membrane. desolate membrane. (2) A photoresponsive polymer characterized by retaining tris (polypyridyl) metal (ID complex and redox reagent), which is a metal of group Ⅰ of the periodic table, in the polyanion type polymer electrolyte film. Electrolyte membrane. (8) Tris (polypyridyl), a group V■ metal of the periodic table.
A polyanionic polymer electrolyte membrane that retains a metal (II) complex and a redox reagent and, if necessary, metal fine particles, and a thin film of an electrically conductive or semiconductive substance deposited on at least one side of the membrane. A photoresponsive polymer decomposition-resistant membrane.