Batteries: thermoelectric and photoelectric – Photoelectric – Cells
Reexamination Certificate
2000-08-03
2002-04-23
Diamond, Alan (Department: 1753)
Batteries: thermoelectric and photoelectric
Photoelectric
Cells
C136S256000, C429S111000, C429S307000, C429S304000, C429S324000, C429S326000, C429S327000, C429S328000, C429S336000, C429S339000, C252S062200, C546S297000, C546S301000, C546S339000, C546S347000, C546S001000, C548S347100, C548S349100, C548S354100
Reexamination Certificate
active
06376765
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electrolyte composition excellent in durability and a charge-transporting capability, a photoelectric conversion device comprising the electrolyte composition, and a photo-electrochemical cell composed thereof. The present invention also relates to a novel imidazolium compound and a novel pyridinium compound, which can be used for the electrolyte composition.
Conventionally, an electrolysis solution prepared by dissolving an electrolyte salt in a solvent has been used as an electrolyte for electrochemical devices such as a cell, a capacitor, a sensor, a display device, a recording device, etc. However, the electrochemical device comprising the prior art electrolysis solution often causes leakage of the solution during long-term operation or storage to be unreliable.
Nature, vol. 353, pp. 737-740 (1991), U.S. Pat. No. 4,927,721, etc. disclosed a photoelectric conversion device comprising dye-sensitized semiconductor particles, and a photo-electrochemical cell composed thereof. However, since the device also comprises the electrolysis solution in a charge-transporting layer, there is still a fear that its photoelectric conversion efficiency is extremely lowered, or its function is lost by leakage or depletion of the electrolysis solution during the long-term operation or storage.
Under these circumstances, International Patent No. 93/20565 disclosed a photoelectric conversion device comprising a solid electrolyte. Further, Nippon Kagaku Kaishi, 7, 484 (1997), Japanese Patent Laid-Open No. 7-2881142, Solid State Ionics, 89, 263 (1986) and Japanese Patent Laid-Open No. 9-27352 proposed a photoelectric conversion device using a solid electrolyte comprising a poly(ethylene oxide)-based, cross-linked polymer. However, the devices using the solid electrolyte are insufficient in photoelectric conversion characteristics, especially short-circuit current density. Additionally, durability of the devices is also insufficient.
Further, disclosed in WO 95/18456, Japanese Patent Laid-Open No. 8-259543, Denki Kagaku, 65, 11, 923 (1997), etc. is a method where a pyridinium salt, an imidazolium salt, a triazolium salt, etc. is used as the electrolyte for the photoelectric conversion device to prevent the leakage and depletion of the electrolytic solution. The salts are molten salts which are liquid at room temperature. The durability of the device is improved because solvents for dissolving the electrolyte such as water and organic solvents are not necessary or needed in only a little amount. However, the device using the molten salt generally has such a defect as a low photoelectric conversion efficiency.
OBJECT AND SUMMARY OF THE INVENTION
An first object of the present invention is to provide an electrolyte composition excellent in durability and a charge-transporting capability, a photoelectric conversion device comprising the electrolyte composition that exhibits high durability and excellent photoelectric conversion properties, and a photo-electrochemical cell composed thereof.
Another object of the present invention is to provide a novel imidazolium compound and a novel pyridinium compound, which can be used for the electrolyte composition.
As a result of intense research in view of the above objects, the inventors have found that an electrolyte composition comprising a compound having a substituent containing repetition of a substituted or unsubstituted ethyleneoxy group at a particular position is excellent in the durability and the charge-transporting capability. The present invention has been accomplished by the finding.
Thus, an electrolyte composition of the present invention comprises a compound represented by the following general formula (1):
wherein R represents a substituent containing a —(CR
1
R
2
—CR
3
R
4
—O)
n
— bond (in which R
1
to R
4
are independently a hydrogen atom or an alkyl group, n being an integer of 2 to 20); Q represents an atomic group forming an aromatic cation having a 5- or 6-membered ring structure with a nitrogen atom, and may have a substituent; and X
−
represents an anion. The electrolyte composition can be preferably used for a photo-electrochemical cell.
A photoelectric conversion device of the present invention has an electrically conductive layer, a photosensitive layer, a charge-transporting layer and a counter electrode, and the charge-transporting layer comprises the electrolyte composition of the present invention. The photoelectric conversion device exhibits the high durability and the excellent photoelectric conversion properties.
Further, a photo-electrochemical cell of the present invention comprises the photoelectric conversion device.
With respect to the electrolyte composition, the photoelectric conversion device and the photo-electrochemical cell of the present invention, the durability, the charge-transporting capability and the photoelectric conversion properties are further improved by satisfying any of the following conditions.
(1) Q preferably has a substituent containing a —(CR
1
R
2
—CR
3
R
4
—O)
n
— bond (in which R
1
to R
4
are independently a hydrogen atom or an alkyl group, n being an integer of 2 to 20).
(2) Q is preferably composed of atoms selected from the group consisting of carbon, hydrogen, nitrogen, oxygen and sulfur atoms.
(3) The 5- or 6-membered ring formed by Q is particularly preferably an imidazole ring or a pyridine ring.
(4) It is preferable that the compound represented by the general formula (1) is further represented by the following general formula (2) or (3):
wherein R
5
represents a substituent containing a —(CR
1
R
2
—CR
3
R
4
—O)
n
— bond (in which R
1
to R
4
are independently a hydrogen atom or an alkyl group, n being an integer of 2 to 20); R
6
to R
10
independently represent a hydrogen atom or a substituent; X
−
represents an anion; and two or more of said R
5
to R
10
may be bonded together to form a ring.
(5) n in the general formula (1), (2) or (3) is preferably an integer of 2 to 6.
(6) The total number of —CR
1
R
2
—CR
3
R
4
—O— bonds (in which R
1
to R
4
are independently a hydrogen atom or an alkyl group) in the compound represented by the general formula (1) is preferably 4 to 6.
(7) X
−
is preferably I
−
, N
−
(CF
3
SO
2
)
2
, BF
4
−
, R
a
—COO
−
(in which R
a
is a hydrogen atom, an alkyl group, a perfluoroalkyl group or an aryl group), R
b
—SO
3
−
(in which R
b
is an alkyl group, a perfluoroalkyl group or an aryl group) or SCN
−
, more preferably I
−
.
(8) It is preferable that the electrolyte composition further comprises an iodine salt in addition to the compound represented by the general formula (1). A cation of the iodine salt is preferably a nitrogen-containing aromatic cation having a 5- or 6-membered ring structure.
(9) In the case where X
−
is I
−
, it is preferable that the electrolyte composition comprises a salt containing an anion selected from the group consisting of N
−
(CF
3
SO
2
)
2
, BF
4
−
, R
a
—COO
−
(in which R
a
is a hydrogen atom, an alkyl group, a perfluoroalkyl group or an aryl group), R
b
—SO
3
−
(in which R
b
is an alkyl group, a perfluoroalkyl group or an aryl group) and SCN
−
. A cation of the salt is preferably a nitrogen-containing aromatic cation having a 5- or 6-membered ring structure.
(10) It is preferable that the electrolyte composition further comprises iodine.
(11) A solvent-content of the electrolyte composition is particularly preferably 10 weight % or less based on the total thereof.
(12) The photosensitive layer of the photoelectric conversion device preferably comprises semiconductor fine particles sensitized by a dye. The semiconductor fine particles are preferably composed of a metal chalcogenide, and the metal chalcogenide is preferably TiO
2
. The dye is preferably a metal complex dye and/or a methine dye.
A novel imidazolium compound represented by the following general formula (4):
wherein R
401
represents a substituent; R
402
to R
405
independent
Ono Michio
Qian Chang-yi
Wariishi Koji
LandOfFree
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