JP2008153047A - Photoelectric conversion element, solar cell, and optical sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion element excellent in photoelectric conversion efficiency or the like and showing stable performance, as well as a solar cell and an optical sensor. <P>SOLUTION: The photoelectric conversion element contains a pyrene system compound with high photoelectric conversion efficiency as a photoelectric conversion material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion element, a solar cell, and an optical sensor using a pyrene compound as a photoelectric conversion material.

  As other application examples of photoelectric conversion materials, in the field of solar cells and photosensors, technological development of photoelectric conversion materials using organic compounds at lower costs than those using conventional silicon semiconductors has been active.

  For this reason, the development of pigments and dyes having high sensitivity to short wavelength light of 350 nm to 600 nm is desired as photoelectric conversion materials.

  Conventionally, azo pigments and the like are known as pigments applied to optical sensors (Patent Document 1), but sufficient characteristics can be obtained even when these pigments are used as photoelectric conversion materials for solar cells or optical sensors. It is not done.

  Moreover, as a solar cell or an optical sensor using an organic compound, a Schottky photoelectric conversion element that joins a p-type organic semiconductor and a metal having a small work function, a p-type organic semiconductor and an n-type inorganic semiconductor, or a p-type organic semiconductor. And a heterojunction photoelectric conversion element that joins an electron-accepting organic compound. The organic compound photoelectric conversion materials used for these include synthetic dyes and pigments such as chlorophyll, perylene and disazo, conductive polymer materials such as polyacetylene, or composite materials thereof, and these can be vacuum deposited or cast. A photoelectric conversion element is formed by thinning the film by a method or a dipping method. However, solar cells using these photoelectric conversion elements have a problem that conversion efficiency is low and durability is poor.

  Further, by adsorbing a ruthenium complex-based dye on a porous titanium oxide electrode, it has now reached the same level of performance as a silicon solar cell (for example, Non-Patent Document 1).

  However, although the ruthenium complex dyes are known to have relatively excellent characteristics, the dyes are expensive, and there is concern about ruthenium, which is the central metal of the complex, as a rare element and stable supply in the future. Therefore, organic dyes that are cheaper and can be stably supplied are more preferable.

  Many organic dyes have been studied as alternatives to this ruthenium complex dye. For example, in addition to ruthenium complex dyes, merocyanine dyes, xanthene dyes, coumarin dyes, acridine dyes, phenylmethane However, the photoelectric conversion efficiency when these dyes are used is not yet sufficient, and there has been a demand for an organic dye that can constitute a photoelectric conversion element with higher conversion efficiency.

In addition, since dye-sensitized solar cells need to adsorb a dye to the surface of a nano-sized porous oxide semiconductor as described above, many solvent-soluble organic dyes are used, but organic dyes are generally durable. The solar cell used outdoors has a large deterioration in the high photoelectric conversion efficiency obtained in the initial stage. That is, the dye-sensitized solar cell is desired to have high durability in addition to high photoelectric conversion efficiency.
Japanese Patent Laid-Open No. 10-125976 J. et al. Am. Chem. Soc. 115 (1993) 6382

  The present invention has been made to solve the above problems. An object of the present invention is to provide a photoelectric conversion element using a novel photoelectric conversion material having high photoelectric conversion efficiency and useful as a solar cell or an optical sensor, and a solar cell and an optical sensor using the photoelectric conversion element. is there.

  As a result of searching for a new compound having high photoelectric conversion efficiency and improved durability, the present inventors have found a novel photoelectric conversion material having a high photoelectric conversion efficiency in the vicinity of a wavelength of 350 to 600 nm. completed.

That is, the present invention is achieved by forming a photoelectric conversion element using a pyrene compound having the following chemical structure as a photoelectric conversion material, a solar cell using the photoelectric conversion element, and an optical sensor.
1. A photoelectric conversion element comprising a pyrene compound containing at least one of the following general formulas (1) to (3) as a photoelectric conversion material.

(In the general formulas (1) to (3), X represents a divalent aromatic group or a divalent heterocyclic group, and R represents a monovalent aromatic group or a heterocyclic group.)
2. 2. The photoelectric conversion element as described in 1 above, wherein, in the thermogravimetric analysis of the pyrene compound, a mass reduction rate D400 / 450 from 400 ° C. to 450 ° C. defined by the following formula is 1.0% or less. .

D400 / 450 = {(G400−G450) / Gi} × 100
However, Gi is a mass at the start of measurement, and G400 and G450 are masses at 400 ° C. and 450 ° C.
3. 3. The photoelectric conversion element as described in 2 above, wherein the pyrene compound is obtained by multi-stage sublimation purification.
4). 3. The photoelectric conversion element as described in 2 above, wherein the pyrene compound is obtained by train sublimation purification.
5. 3. The photoelectric conversion element as described in 2 above, wherein the pyrene compound is obtained by heat treatment in a high boiling point solvent.
6). 3. The photoelectric conversion element as described in 2 above, wherein the pyrene compound is obtained by an acid paste treatment.
7). A solar cell comprising the photoelectric conversion element according to any one of 1 to 6 above.
8). An optical sensor comprising the photoelectric conversion element according to any one of 1 to 6 above.

  By using the pyrene compound of the present invention as a photoelectric conversion material to constitute a photoelectric conversion element, a solar cell, and an optical sensor, a photoelectric conversion element, a solar cell, and an optical sensor that exhibit high photoelectric conversion efficiency and excellent stability are obtained. Can be provided.

  Hereinafter, the present invention will be described in detail.

  The pyrene compound according to the present invention uses at least one of the general formulas (1) to (3) as a photoelectric conversion material.

  When the pyrene compound is represented by any one of the general formulas (1) to (3), the photoelectric conversion material has high-efficiency photoelectric conversion characteristics with respect to short-wavelength light, and is high. It is possible to provide and provide a photoelectric conversion element, a solar cell, and an optical sensor that exhibit photoelectric conversion efficiency and excellent stability.

  Hereinafter, the pyrene compound according to the present invention will be described.

  The pyrene compound according to the present invention has at least one chemical structure represented by the general formulas (1) to (3).

  In the general formulas (1) to (3), the divalent aromatic group represented by X and the divalent heterocyclic group include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyridine ring, Anthraquinone rings and the like can be mentioned, and particularly preferred are divalent groups introduced from a benzene ring, a naphthalene ring or the like. Examples of the substituent for X include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, an acyloxy group, a halogen atom, a nitro group, and a cyano group.

  Examples of R include substituted and unsubstituted phenyl groups, naphthyl groups, furyl groups, thienyl groups, and pyridyl groups. Particularly preferred are substituted and unsubstituted phenyl groups and naphthyl groups. Examples of the substituent on R include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, an acyloxy group, a halogen atom, a nitro group, and a cyano group.

  These compounds have a large potential attenuation value per unit exposure amount with respect to an exposure light source having a wavelength of 350 to 500 nm, and can form a small dot latent image sharply.

  The pyrene compound represented by the general formula (1) to the general formula (3) includes a pyrene-1,2,6,7-tetracarboxylic dianhydride derivative represented by the following general formula (6) and a general formula. It is produced by a dehydration condensation reaction of the diamino compound represented by (7).

(In General Formula (6), R is the same as R in General Formula (1) to General Formula (3). In General Formula (7), X is X in General Formula (1) to General Formula (3). Is the same as
The pyrene compounds represented by the general formulas (1) to (3) are structural isomers of each other, and the compounds produced in the condensation reaction are produced as a mixture of these structural isomers. However, even if they are used without being isolated, the effects of the present invention can be exhibited well. In the specific examples of the general formulas (1) to (3) described below, it is assumed that each compound can take a structural isomer. In the examples described later, organic photoreceptors are produced using a mixture of structural isomers as they are.

  Specific examples of the pyrene-based compound represented by any one of the general formula (1) to the general formula (3) are illustrated below.

  Next, synthesis examples of the above exemplary compounds will be described.

Synthesis Example 1 (C-1)
3,8-diphenylpyrene-1,2,6,7-tetracarboxylic dianhydride 2.5 g (0.005 mol), o-phenylenediamine 1.6 g (0.015 mol), anhydrous zinc chloride 1 g (0.001 mol) was heated to reflux in 50 ml of quinoline for 2 hours, and the precipitated crystals were collected by filtration. After washing with acetone and methanol, it was dried to obtain 2.8 g (88%) of Exemplified Compound C-1.

  The pyrene compound of the present invention preferably has a mass reduction rate D400 at 400 ° C. defined by the following formula of 1.0% or less in thermogravimetric analysis.

D400 = {(Gi−G400) / Gi} × 100
However, Gi is the mass at the start of measurement, and G400 is the mass at 400 ° C.

  The mass reduction rate D400 is a mass reduction rate produced when the pyrene compound is heated from room temperature to 400 ° C. This measurement can be performed under the following conditions.

  About 5 mg of sample was heated at a rate of 10 ° C. per minute under a nitrogen stream of 100 ml / min by “differential thermogravimetric simultaneous measurement device TG / DTA6200” (manufactured by Seiko Instruments Inc.). The mass reduction rate that occurs when the temperature is raised to 400 ° C. from the start of measurement (room temperature) is measured.

  In the pyrene compounds of the general formulas (1) to (3), the mass reduction rate in the above temperature range seems to indicate the amount of impurity components that volatilize near the sublimation point of the pyrene compounds, If such an impurity component is contained in a large amount in the pigment of the pyrene compound, it is considered that a large amount of impurity levels are generated in the pigment, which adversely affects the characteristics of the solar cell and the optical sensor.

  Next, with respect to a method for purifying a pyrene compound having a mass reduction rate of 1.0% or less according to the present invention using the pyrene compound (pigment) obtained in Synthesis Example 1, the following a to d ( Specific description will be given in the purification treatments a to d) of the pyrene compound.

a. Pyrene compounds obtained by multi-stage sublimation purification Multi-stage sublimation purification includes two or more sublimation steps. The first stage condenses an effective amount, for example about 1-10% by weight of the sublimate, onto the first substrate at a temperature slightly above the sublimation temperature of the pigment. Subsequently, in the second stage, the sublimation temperature is raised in the range of 10 to 100 ° C., and the sublimate is condensed on the second substrate, whereby a high-purity pigment containing no volatile impurities or decomposition impurities can be obtained. Depending on the case, three or more steps may be included.

Purification Example 1 (Specific example of multi-stage sublimation purification)
After putting 5 g of the pyrene compound (C-1) obtained in Synthesis Example 1 into a crucible and depressurizing the chamber of the sublimation apparatus to about 133.3 mPa to 13.3 mPa, the temperature of the crucible is raised at 420 ° C. to 10 Maintained for minutes and heat was turned off. When the temperature of the crucible became 200 ° C. or lower, the pressure in the chamber was changed to atmospheric pressure, and 0.5 g of sublimate (first stage sublimation C-1) was collected from the collector substrate. Next, after the pressure of the chamber of the sublimation apparatus was reduced to about 133.3 mPa to 13.3 mPa, the temperature of the crucible was heated at 450 ° C. for 2 hours. After cooling, 4.2 g of a pyrene compound (second stage sublimation C-1) attached to the collector substrate was obtained. The mass reduction rate of C-1 was 0.5%.

b. Pyrene-based compounds obtained by fractional sublimation purification In fractional sublimation purification, the pigment is first heated to a temperature T1 at a first position to evaporate the pigment and volatile impurities contained therein, and then maintained at a temperature T2 lower than T1. This is done by condensing the pigment vapor at the second position and then condensing the vapor of volatile impurities at the third position maintained at a temperature T3 lower than T2. Non-sublimable impurities remain in the first position with the starting material, and a purified pigment separated from volatile impurities is obtained. The fractional sublimation method of the present invention includes known purification methods such as train sublimation.

Purification example 2 (specific example of fractional sublimation purification)
5 g of the pyrene compound (C-1) obtained in Synthesis Example 1 was placed in a Pyrex (registered trademark) glass tube, and the tube was subjected to a temperature gradient (1 m) of about 480 ° C. to about 20 ° C. along the length of the tube. At a temperature gradient of about 480 ° C. to about 20 ° C.). The inside of the glass tube was depressurized to about 133.3 mPa to 13.3 mPa, and the position where the pyrene pigment to be purified was placed was heated to about 480 ° C. The generated vapor was transferred to the low temperature side of the tube and condensed to obtain 4.4 g of a pyrene compound (C-1) sublimate condensed in a region between about 300 to 420 ° C. The mass reduction rate of C-1 was 0.24%.

c. A pyrene compound obtained by heat treatment in a high-boiling solvent Heat treatment in a high-boiling solvent is a recrystallization or washing by heating an unpurified pigment in a high-boiling solvent having a boiling point of 150 ° C. or higher. It is to remove impurities that are highly soluble in the solvent. Preferred high boiling point solvents in the present invention include o-dichlorobenzene, 1-chloronaphthalene, nitrobenzene, quinoline, sulfolane and the like.

Purification Example 3 (Specific example of heat treatment in a high boiling point solvent)
5 g of the pyrene compound (C-1) obtained in Synthesis Example 1 is put in a crucible, the pressure of the chamber of the sublimation apparatus is reduced to about 133.3 mPa to 13.3 mPa, and then the temperature of the crucible is raised to 450 ° C. for 2 hours. Heated. After cooling, the pressure inside the chamber was changed to atmospheric pressure to obtain 4.5 g of sublimate adhering to the collector substrate. Next, 1.0 g of the sublimate was suspended in 100 ml of quinoline, heated at 200 ° C. for 1 hour, filtered, washed with acetone and then methanol, and dried to obtain purified C-1. The mass reduction rate of C-1 was 0.51%.

d. Pyrene-based compounds obtained by acid paste treatment Acid paste treatment is a process in which pigment is dissolved in a strong acid such as sulfuric acid, chlorosulfuric acid or trifluoroacetic acid and then poured into water to form fine particles, and at the same time, removal of water-soluble inorganic impurities and pigment particles This is a treatment that promotes the amorphization of the phthalocyanine, and is a treatment technique often used for phthalocyanine pigments. The acid paste treatment of the pyrene compound of the present invention is preferably performed using trifluoroacetic acid.

  Since the acid paste-treated pigment is a fine particle, the crystal after filtration after washing with water usually contains water 5 to 10 times the mass of the pigment and is obtained in the form of a wet cake or hydrous paste. Is dried to obtain the desired pigment.

Purification Example 4 (Specific example of acid paste treatment)
5 g of the pyrene compound (C-1) obtained in Synthesis Example 1 is put in a crucible, the pressure of the chamber of the sublimation apparatus is reduced to about 133.3 mPa to 13.3 mPa, and then the temperature of the crucible is raised to 450 ° C. for 2 hours. Heated. After cooling, the pressure inside the chamber was changed to atmospheric pressure to obtain 4.5 g of sublimate adhering to the collector substrate. Next, 1.0 g of the sublimate was dissolved in 30 ml of trifluoroacetic acid, and this was added dropwise to 500 ml of water. The precipitated pigment was filtered, suspended in 200 ml of water and washed. Washing with water was repeated until the electrical conductivity of the cleaning liquid reached 100 μS / less, and the resulting wet cake was dried to obtain purified C-1. The mass reduction rate of C-1 was 0.76%.

<< Photoelectric conversion element >>
The photoelectric conversion element of the present invention will be described with reference to FIG.

  FIG. 1 is a partial cross-sectional view showing an example of the structure of the photoelectric conversion element of the present invention.

  Reference numeral 1 denotes a transparent electrode, 2 denotes a photosensitive layer, 3 denotes a charge transfer layer, 4 denotes a counter electrode, and 5 denotes a partition wall. The transparent electrode 1 and the photosensitive layer 2 are also collectively referred to as a photoelectrode.

Transparent electrode The transparent electrode 1 includes a base 1a and a transparent electrode film 1b.

  The transparent electrode used in the photoelectric conversion element of the present invention and the solar cell of the present invention has a structure in which a conductive material is provided on a conductive material such as a metal plate or a non-conductive support such as a glass plate or a plastic film. Can be used. Examples of materials used for the conductive substance include metals (eg, platinum, gold, silver, copper, aluminum, rhodium, indium) or conductive metal oxides (eg, indium-tin composite oxide, tin oxide doped with fluorine) And carbon). The thickness of the transparent electrode is not particularly limited, but is preferably 0.3 mm to 5 mm.

  Further, the transparent electrode is preferably substantially transparent, and being substantially transparent means that the light transmittance is 10% or more, more preferably 50% or more, and 80% or more. Most preferably. In order to obtain a transparent electrode, it is preferable to provide a conductive layer made of a conductive metal oxide on the surface of a glass plate or a plastic film. The light is preferably incident from the transparent electrode side.

The surface resistance of the transparent electrode is preferably 50 Ω / cm ² or less, more preferably 10 Ω / cm ² or less.

  The photosensitive layer 2 is a layer containing the pyrene compound of the present invention as a photoelectric conversion material, and the charge transfer layer 3 usually contains a redox electrolyte and is in contact with the transparent electrode 1, the photosensitive layer 2, and the counter electrode 4. Used.

  In the photoelectric conversion element of the present invention, the photosensitive layer 2 preferably has a pn heterojunction type multilayer structure or a dye-sensitized single layer structure. In the pn junction type multilayer structure, an n-type semiconductor layer such as a phthalocyanine pigment is provided on a transparent electrode 1 as shown in FIG. 1, and a p-type semiconductor layer of a pyrene compound pigment of the present invention is provided thereon. The photosensitive layer 2 is formed.

  A pn junction type layer structure can be formed by dispersing a p-type or n-type pigment in a solvent and, if necessary, a medium such as a binder, and applying a dispersion obtained by the dispersion. Alternatively, the pn junction layer may be sintered after coating to form a pn junction type sintered layer.

  Examples of the pigment used for the n-type semiconductor layer include titanium oxide and zinc oxide in addition to the phthalocyanine pigment.

  The thickness of the p-type or n-type semiconductor layer is preferably in the range of 0.05 to 1 μm. Moreover, it is preferable that the content rate of the pigment contained in each layer of p or n is 30 mass% or more for each layer. Further, in the case of a pn junction type photoelectric conversion element, the charge transfer layer 3 in FIG. 1 is not necessary, and it is preferably composed of a transparent electrode, a photosensitive layer and a counter electrode.

Counter electrode The counter electrode 4 includes a base 4a, a transparent conductive film 4b, and a conductive layer 4c such as gold or platinum. The substrate 4a and the transparent conductive film 4b are manufactured using the same materials as those of the transparent electrode substrate 1a and the transparent electrode film 1b. The conductive layer 4c only needs to have conductivity, and an arbitrary conductive material is used. Examples thereof include a gold electrode, a platinum electrode, a material obtained by depositing gold or platinum on the surface of a conductive material, rhodium metal, ruthenium metal, ruthenium oxide, and carbon.

  On the other hand, in the dye-sensitized structure, the photosensitive layer is formed of a semiconductor layer such as titanium oxide, and the photosensitive layer 2 is color-sensitized by adsorbing the pyrene compound according to the present invention to the semiconductor layer. To do. In the case of this dye-sensitized type, the pyrene compound is dissolved in an appropriate solvent, and the semiconductor layer formed on the transparent electrode 1 is immersed in the solution. At that time, the semiconductor layer is preferably subjected to a firing treatment. By baking treatment, it is considered that a semiconductor material such as titanium oxide easily adsorbs a pyrene-based compound, and the color sensitization effect is enhanced. In addition, it is preferable that the semiconductor layer is preliminarily subjected to pressure reduction treatment or heat treatment to remove bubbles in the film so that the pyrene compound can enter deep inside the semiconductor layer.

Semiconductor materials used for the dye-sensitized semiconductor layer include SnO ₂ , Fe ₂ O ₃ , WO ₃ , ZnO, Nb ₂ O ₅ , CdS, ZnS, PbS, and Bi in addition to the titanium oxide (TiO ₂ ). ₂ S ₃ , CdSe, CdTe, GaP, InP, GaAs, CuInS ₂ , CuInSe ₂ , Ti ₃ N _{4 and the} like can be mentioned, but preferably used are TiO ₂ , ZnO, SnO ₂ , Fe ₂ O ₃ , WO ₃ , Nb ₂ O ₅ , CdS, and PbS. Of these, metal oxides or metal sulfide semiconductors are preferably used. Of these, a metal oxide semiconductor is more preferably used, and among them, TiO ₂ or Nb ₂ O ₅ is used, and TiO ₂ is more preferably used.

  In forming the photosensitive layer 2, the solvent used for dispersion or dissolution of the pyrene compound or titanium oxide is not particularly limited. For example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, cyclohexanol, Alcohols such as glycidol, furfuryl alcohol, benzyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Glycol derivatives such as butyl ether acetate, o-xylene, toluene, cyclohexane Hydrocarbons such as ethyl acetate, esters such as ethyl acetate, acetic acid-n-propyl, acetic acid-n-butyl, butyrolactone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, methyl-n-pentyl ketone, methyl isobutyl Ketones such as ketone, cyclopentanone, cyclohexanone, and cycloheptanone are exemplified.

  In the dye-sensitized structure, when the photosensitive layer 2 is formed on the transparent electrode 1, the counter electrode 4 is disposed so as to face the photosensitive layer 2. Further, a redox electrolyte as a charge transfer layer is injected between the semiconductor electrode and the counter electrode 4 to obtain a photoelectric conversion element.

《Solar cell》
The solar cell of the present invention will be described.

  In the solar cell of the present invention, as one aspect of the photoelectric conversion element of the present invention described above, optimal design and circuit design for sunlight are performed, and optimal photoelectric conversion is performed when sunlight is used as a light source. It has such a structure. That is, the semiconductor for photoelectric conversion material has a structure that can be irradiated with sunlight. When configuring the solar cell of the present invention, the entire solar cell structure is preferably resin-sealed.

  When the solar cell of the present invention is irradiated with sunlight or an electromagnetic wave equivalent to sunlight, the photoelectric conversion element using the pyrene compound of the present invention as a photoelectric conversion material absorbs the irradiated light or electromagnetic wave and excites it. The electrons or holes generated by the excitation then move to move to the counter electrode 4 via the transparent electrode 1. In this way, electrons flow, and a solar cell using the photoelectric conversion element of the present invention can be configured.

《Light sensor》
The optical sensor of the present invention can be used for an optical sensor for a digital camera using a solid-state imaging system such as a CCD or CMOS. As the basic structure of the optical sensor is described in Japanese Patent Application Laid-Open No. 2003-234460, etc., the photoelectric conversion film (electromagnetic wave absorption / photoelectric conversion part) and the scanning circuit part (charge transfer / reading part) are made of a conductive material. However, the photosensor of the present invention uses the pyrene compound as a photoelectric conversion material as a photoelectric conversion material for the photoelectric conversion film, and is used as a material that can improve the photoelectric conversion efficiency of the blue or green part. It is done.

  The photoelectric conversion film of the optical sensor can be configured with substantially the same structure as the photoelectric conversion element described above. However, an opaque conductive support is preferable for the counter electrode on the side where light is not directly incident. As such a support, an aluminum or copper metal support, a sheet surface-treated with these metals, or the like is preferably used.

  These photoconductive films may be laminated with another photoelectric conversion film having a long wavelength sensitivity of red or green to form a photoelectric conversion film corresponding to white or full color.

  These photoelectric conversion films are electrically connected to the scanning circuit unit, and can constitute an optical sensor.

  The scanning circuit unit can appropriately adopt a configuration in which a MOS transistor is formed on a semiconductor substrate for each pixel unit, or a configuration having a CCD as an image sensor.

  For example, in the case of a solid-state imaging device using a MOS transistor, charges are generated in the photoconductive film by incident light transmitted through the electrodes, and the charges are generated by an electric field generated between the electrodes by applying a voltage to the electrodes. It travels to the electrode through the photoconductive film, and further moves to the charge storage part of the MOS transistor, and charges are stored in the charge storage part. The charge accumulated in the charge accumulation unit moves to the charge readout unit by switching of the MOS transistor, and is further output as an electric signal. Thereby, a full-color image signal is input to the solid-state imaging device including the signal processing unit.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the following text, “part” means “part by mass”.

(Example 1)
<< Production of Photoelectric Conversion Element 101 >>
A titanyl phthalocyanine layer having a thickness of 0.4 μm was formed by vapor deposition on a transparent conductive glass plate coated with tin oxide doped with fluorine (transparent electrode 1). On this titanyl phthalocyanine layer (N layer), a pyrene-based compound layer (P layer) having a thickness of 0.5 μm was formed by vapor deposition (Exemplary Compound C-1: Mass reduction rate of multistage sublimation purification: 0.50%) Furthermore, a 1 μm-thick gold layer was formed thereon as a counter electrode 4 by vapor deposition, and a PN junction type photoelectric conversion element 101 was produced.

<< Preparation of Photoelectric Conversion Elements 102-106 >>: Present Invention In the preparation of photoelectric conversion element 101, photoelectric conversion was performed in the same manner except that pyrene-based compound (C-1) was changed to each of the exemplified compounds shown in Table 1. Elements 102 to 106 were obtained.

<< Preparation of Photoelectric Conversion Element 107 >> Comparative Example Photoelectric conversion was performed in the same manner as in the preparation of the photoelectric conversion element 101 except that the pyrene compound (C-1) was changed to the following comparative compound CR shown in Table 1. Element 107 was obtained.

(Example 2)
<< Preparation of Solar Cells SC-101 to SC-107 >>: After the side surfaces of the photoelectric conversion elements 101 to 107 of the present invention are sealed with resin, lead wires are attached, and the solar cells SC-101 to SC-107 of the present invention are attached. Three lots were prepared for each.

<< Evaluation of photoelectric conversion efficiency of solar cells >>
When each of the solar cells SC-101 to SC-107 obtained above was irradiated with light having an intensity of 100 mW / m ² by a solar simulator (manufactured by JASCO (JASCO), low energy spectral sensitivity measuring device CEP-25). The photoelectric conversion efficiency was measured and shown in Table 1. The indicated value was the average value of the measurement results for three solar cells having the same configuration and production method.

Evaluation of photoelectric conversion efficiency (energy conversion efficiency) The above-described solar cells SC-101 to SC-107 were tested to evaluate the respective photoelectric conversion efficiency (energy conversion efficiency η). This evaluation test was conducted using a solar simulator (trade name: “WXS-85-H type” manufactured by Wacom Denso Co., Ltd.) and 100 mW / cm ² from a xenon lamp that passed through an AM filter (AM-1.5). The following procedure was performed by irradiating simulated sunlight.

  For each solar cell immediately after completion, the current-voltage characteristics were measured at room temperature using an IV tester, and the short circuit current (Jsc), the open circuit voltage (Voc), and the fill factor (FF) were obtained. From these, the photoelectric conversion efficiency (η (%)) was determined. In addition, the photoelectric conversion efficiency ((eta) (%)) of the solar cell was computed based on the following formula (A).

η = 100 × (Voc × Jsc × FF) / P (A)
Here, P is the incident light intensity [mW / cm ⁻² ], Voc is the open circuit voltage [V], Jsc is the short-circuit current density [mA · cm ⁻² ], F.V. F. Indicates a fill factor. Table 2 shows the photoelectric conversion efficiency obtained as a result.

From Table 2, the solar cells SC-101 to SC-106 of the present invention exhibit high photoelectric conversion characteristics, and it is effective to use the pyrene compounds of the general formulas (1) to (3) as the light conversion material of the solar cell. It is shown that. Among them, the SC-101 to SC-105 solar cells subjected to the multi-stage sublimation purification show particularly excellent effects. On the other hand, it is confirmed that the solar cell SC-107 of the comparative example has a significantly lower photoelectric conversion efficiency than the solar cell of the present invention. In addition, the solar cells SC-101 to SC-106 of the present invention are excellent in stability because no decrease in photoelectric conversion efficiency is observed even after 100 hours of light irradiation of 100 mW / m ² by a solar simulator. It was confirmed.

(Example 3)
<< Operation Confirmation of Optical Sensor >>: The operation of the optical sensor is confirmed in the following manner using the photoelectric conversion elements 101 to 107 (corresponding optical sensor Nos. Are LC-101 to LC-107). did.

  The usefulness as an optical sensor was evaluated by evaluating the current change by light irradiation of these optical sensors LC-101 to LC-107.

  Evaluation was performed by irradiating a light source of a xenon lamp (L2274, manufactured by Hamamatsu Photonics) with blue light obtained through a blue filter at an intensity of 20 lux with an applied voltage of 10 V applied to both ends of these photosensors. Irradiation light intensity was measured with an illuminometer (Minolta). The filter used has a characteristic that an average transmittance of 400 to 500 nm is 80% or more.

  Measure the steady current 2.0 seconds after the start time of light irradiation and increase the current value relative to the steady current before light irradiation (steady current 2.0 seconds after the start time / steady state before light irradiation). Current) was calculated to evaluate each optical sensor. The results are shown in Table 3.

  From Table 3, it can be seen that the increase rate of the current value of the photosensors LC-101 to LC-106 is excellent and high as compared with the photosensor LC-107 of the comparative example.

Example 4
<< Production of Photoelectric Conversion Element 111 >>
A titanyl phthalocyanine layer having a thickness of 0.4 μm was formed by vapor deposition on a transparent conductive glass plate coated with tin oxide doped with fluorine (transparent electrode 1). On this titanyl phthalocyanine layer (N layer), a pyrene-based compound layer (P layer) having a film thickness of 0.5 μm was formed by vapor deposition (Exemplary Compound C-1: Mass reduction rate of fractional sublimation purification 0.24%) Furthermore, a 1 μm-thick gold layer was formed thereon as a counter electrode 4 by vapor deposition to produce a PN junction type photoelectric conversion element 111.

<< Preparation of Photoelectric Conversion Elements 112 to 116 >>: Present Invention In the preparation of photoelectric conversion element 101, photoelectric conversion was performed in the same manner except that pyrene-based compound (C-1) was changed to each of the exemplified compounds shown in Table 4. Elements 112 to 116 were obtained.

(Example 5)
<< Preparation of Solar Cells SC-111-SC-116 >>: After Encapsulating the Sides of the Photoelectric Conversion Elements 111-116 with Resin, the Lead Wires are Attached to the Solar Cells SC-111-SC-116 of the Present Invention. Three lots were prepared for each.

<< Evaluation of photoelectric conversion efficiency of solar cells >>
Each of the solar cells SC-111-SC-116 obtained above was evaluated in the same manner as in Example 2. Table 5 shows the results of photoelectric conversion efficiency obtained in this manner.

From Table 5, the solar cells SC-1111 to SC-116 of the present invention exhibit high photoelectric conversion characteristics, and the solar cell is a pyrene compound of the general formulas (1) to (3) and subjected to fractional sublimation purification. It is shown that it is effective to use as a light conversion material. Moreover, the solar cells SC-111-SC-116 of the present invention were confirmed to be excellent in stability because no decrease in photoelectric conversion efficiency was observed even after 100 hours of light irradiation of 100 mW / m ² by a solar simulator. did.

(Example 6)
<< Operation Confirmation of Optical Sensor >>: The operation of the optical sensor is confirmed as follows using the photoelectric conversion elements 111 to 116 (corresponding optical sensor Nos. Are LC-1111 to LC-116) of the present invention. did.

  Changes in current due to light irradiation of these photosensors LC-1111 to LC-116 were evaluated in the same manner as in Example 3 to evaluate their usefulness as photosensors. The results are shown in Table 6.

  From Table 6, it can be seen that the increase rate of the current value of the optical sensors LC-1111 to LC-116 is superior and higher than that of the optical sensor LC-107 of the comparative example.

(Example 7)
<< Production of Photoelectric Conversion Element 121 >>
A titanyl phthalocyanine layer having a thickness of 0.4 μm was formed by vapor deposition on a transparent conductive glass plate coated with tin oxide doped with fluorine (transparent electrode 1). On this titanyl phthalocyanine layer (N layer), a pyrene-based compound layer (P layer) having a film thickness of 0.5 μm was formed by vapor deposition (Exemplary Compound C-1: Mass reduction rate of heat treatment in high boiling point solvent 0 Further, a gold layer having a thickness of 1 μm was formed thereon as a counter electrode 4 by vapor deposition to produce a PN junction type photoelectric conversion element 121.

<< Preparation of Photoelectric Conversion Elements 112 to 116 >>: Present Invention In the preparation of photoelectric conversion element 121, photoelectric conversion was performed in the same manner except that pyrene-based compound (C-1) was changed to each of the exemplified compounds shown in Table 7. Elements 122 to 128 were obtained.

(Example 8)
<< Preparation of Solar Cells SC-121 to SC-128 >>: The present invention The side surfaces of the photoelectric conversion elements 121 to 128 are encapsulated with resin, then lead wires are attached, and the solar cells SC-121 to SC-128 of the present invention are attached. Three lots were prepared for each.

<< Evaluation of photoelectric conversion efficiency of solar cells >>
Each of the solar cells SC-121 to SC-128 obtained above was evaluated in the same manner as in Example 2. Table 8 shows the results of the photoelectric conversion efficiency obtained as described above.

From Table 8, the solar cells SC-121 to SC-128 of the present invention exhibit high photoelectric conversion characteristics, and it is effective to use the pyrene-based compounds of the general formulas (1) to (3) as the light conversion material of the solar cell. It is shown that. Among these, solar cells SC-121 to SC-127 using compounds subjected to heat treatment in a high-boiling solvent show higher photoelectric conversion characteristics. In addition, it was confirmed that the solar cells SC-121 to SC-128 of the present invention were excellent in stability because no decrease in photoelectric conversion efficiency was observed even after 100 hours of light irradiation of 100 mW / m ² by a solar simulator. did.

Example 9
<< Operation check of optical sensor >>: The operation of the optical sensor is confirmed as follows using the photoelectric conversion elements 121 to 128 (corresponding optical sensor Nos. Are LC-121 to LC-128) of the present invention. did.

  Changes in current due to light irradiation of these photosensors LC-121 to LC-128 were evaluated in the same manner as in Example 3 to evaluate their usefulness as photosensors. The results are shown in Table 9.

  From Table 9, it can be seen that the rate of increase in the current value of the photosensors LC-121 to LC-128 is superior to the photosensor LC-107 of the comparative example.

(Example 10)
<< Production of Photoelectric Conversion Element 131 >>
A titanyl phthalocyanine layer having a thickness of 0.4 μm was formed by vapor deposition on a transparent conductive glass plate coated with tin oxide doped with fluorine (transparent electrode 1). On this titanyl phthalocyanine layer (N layer), a 0.5 μm-thick pyrene-based compound layer (P layer) was formed by vapor deposition (Exemplary Compound C-1: Mass reduction rate of 0.76% in acid paste treatment) Furthermore, a 1 μm-thick gold layer was formed thereon as a counter electrode 4 by vapor deposition, and a PN junction type photoelectric conversion element 131 was produced.

<< Preparation of Photoelectric Conversion Elements 132 to 135 >>: Present Invention In the preparation of the photoelectric conversion element 131, photoelectric conversion was performed in the same manner except that the pyrene-based compound (C-1) was changed to each of the exemplified compounds shown in Table 10. Elements 132 to 135 were obtained.

(Example 11)
<< Preparation of Solar Cells SC-131 to SC-135 >>: The Solar Cells SC-131 to SC-135 of the Present Invention are Attached with Leads after Encapsulating the Sides of the Photoelectric Conversion Elements 131 to 135 with Resin Three lots were prepared for each.

<< Evaluation of photoelectric conversion efficiency of solar cells >>
Each of the solar cells SC-131 to SC-135 obtained above was evaluated in the same manner as in Example 2. Table 11 shows the results of the photoelectric conversion efficiency obtained as described above.

From Table 11, the solar cells SC-131 to SC-135 of the present invention exhibit high photoelectric conversion characteristics, and it is effective to use the pyrene compounds of the general formulas (1) to (3) as the light conversion material of the solar cell. It is shown that. In addition, it was confirmed that the solar cells SC-131 to SC-135 of the present invention were excellent in stability because no decrease in photoelectric conversion efficiency was observed even after 100 hours of light irradiation of 100 mW / m ² by a solar simulator. did.

(Example 12)
<< Operation check of optical sensor >>: The present invention uses the photoelectric conversion elements 131 to 135 (corresponding optical sensor Nos. LC-131 to LC-135) to check the operation as an optical sensor in the following manner. did.

  Changes in current due to light irradiation of these photosensors LC-131 to LC-135 were evaluated in the same manner as in Example 3 to evaluate their usefulness as photosensors. The results are shown in Table 12.

  From Table 12, it can be seen that the increase rate of the current values of the photosensors LC-131 to LC-135 is excellent and high as compared with the photosensor LC-107 of the comparative example.

It is a fragmentary sectional view which shows an example of the structure of the photoelectric conversion element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent electrode 2 Photosensitive layer 3 Charge transfer layer 4 Counter electrode

Claims (8)

A photoelectric conversion element comprising a pyrene compound containing at least one of the following general formulas (1) to (3) as a photoelectric conversion material.

(In the general formulas (1) to (3), X represents a divalent aromatic group or a divalent heterocyclic group, and R represents a monovalent aromatic group or a heterocyclic group.) 2. The photoelectric conversion according to claim 1, wherein, in the thermogravimetric analysis of the pyrene-based compound, a mass reduction rate D400 / 450 from 400 ° C. to 450 ° C. defined by the following formula is 1.0% or less. element.
D400 / 450 = {(G400−G450) / Gi} × 100
However, Gi is a mass at the start of measurement, and G400 and G450 are masses at 400 ° C. and 450 ° C. The photoelectric conversion element according to claim 2, wherein the pyrene compound is obtained by multi-stage sublimation purification. The photoelectric conversion element according to claim 2, wherein the pyrene compound is obtained by train sublimation purification. The photoelectric conversion element according to claim 2, wherein the pyrene compound is obtained by heat treatment in a high boiling point solvent. The photoelectric conversion element according to claim 2, wherein the pyrene compound is obtained by an acid paste treatment. A solar cell comprising the photoelectric conversion device according to claim 1. An optical sensor comprising the photoelectric conversion element according to claim 1.

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