KR20070100192A - Dye-sensitized solar cell prepared by low-temperature process using tio2 paste - Google Patents

Abstract

A dye-sensitized solar cell prepared by a low-temperature process using TiO2 paste is provided to develop the entire process for manufacturing the dye-sensitized solar cell. A dye-sensitized solar cell is prepared by a low-temperature process using TiO2 paste. A process for manufacturing inorganic binder sol including high concentration aqueous TiO2 includes a step of mixing water(10) with titanium alkoxide(20) using catalyst(30). Start materials for manufacturing inorganic binder sol including high concentration aqueous TiO2 include titanium alkoxide (TiRO4(20), wherein R=alkyl group), and distilled water(10). A low grade alcohol solvent includes ethanol, methanol, isopropanol, and butanol.

Description

 Dye-sensitized Solar Cell prepared by Low-temperature Process using TiO2 Paste}

  The dye-sensitized solar cell forms a porous titanium oxide film on a conductive substrate (glass, plastic, metal), adsorbs the Ru-based dye of FIG. 1 onto the surface of the titanium oxide, forms a counter electrode, and then injects an electrolyte between the electrodes. To form one cell.

)을 코팅한 유리기판 속에 나노 크기의 산화티탄(

)입자를 페이스트 상으로 도포하여, 이를 450 ℃로 소결한 것을 이용한다. 이때 산화티탄 층의 두께는 10-15μm이고 다공성 구조를 지닌다. 이 산화티탄 입자 표면에 카르복실기를 지닌 루덴니움 바이 피리딘 (Ruthenium bi-pyridine) 흡착체를 흡착시켜 두고, 전해액으로서 니트릴(nitrile)계 용매를 이용한 요오드/요오드화 이온으로 이루어진 레독스 전해액을 광 전극기판(산화티탄 후막 코팅된 ITO유리기판)과 대극 기판(Pt증착된 ITO코팅유리) 사이에 주입하여 밀봉한 샌드위치 구조를 지닌 모듈을 만든다. 태양 광 전환부품에서의 전류 형성 메카니즘을 도 3에 도식적으로 나타낸다. With reference to FIG. 2, the general diagram of a dye-sensitized solar cell is shown. The dye-sensitized solar cell is a negative electrode (photoelectrode) and a transparent conductive film (

Nano-size titanium oxide () in a glass substrate coated with

) The particles are applied in the form of a paste, and those obtained by sintering at 450 캜 are used. At this time, the thickness of the titanium oxide layer is 10-15μm and has a porous structure. A ruthenium bi-pyridine adsorbent having a carboxyl group is adsorbed on the surface of the titanium oxide particles, and a redox electrolyte composed of iodine / iodide ions using a nitrile solvent as an electrolyte is used as a photoelectrode substrate ( A module having a sandwich structure sealed by injection between a titanium oxide thick film coated ITO glass substrate) and a counter electrode substrate (Pt-deposited ITO coated glass) is formed. The current forming mechanism in the solar conversion component is shown schematically in FIG. 3.

)는 전극반도체 페르미 준위와 전해질의 산화환원 포텐셜 차이에 의해 결정된다. Referring to Fig. 3, in the process of ①, the sensitizing dye (currently Ru-based electrons are excited by the visible light irradiation in the sunlight, and the electron transition occurs from the ground state to the excited state. The electrons move to the conduction band of the positive electrode titanium oxide semiconductor, and these electrons move through the external circuit to the opposite electrode (negative electrode; generally Pt electrode is used). Is returned to the sensitizing dye by electrolytic reduction / oxidation, and this process is repeated to generate electrical energy.Unlike other conversion elements, the maximum output potential of the dye-sensitized solar cell (

) Is determined by the difference between the electrode semiconductor Fermi level and the redox potential of the electrolyte.

  In the process of realizing the above,

For flexible film-type solar cell binders and low temperature film formation, electrophoretic devices (Seramics, 39, 439-444 (2004)), autoclaves for hydrothermal devices (D.Zhang, T.Yoshida and H. Minoura, Adv) . Mater., 15, 814-17 ( 2003)), microwave apparatus (Uchida et al,機能材料, 23, 58-63 (2003)), the press device (G.Boschioo, H.Lindatrom, E.Magnusson, A. Homberg and A. Hagfeldt, J. Photochem.Photobiol.A. , 148, 11-15 (2002)), and equipment for film formation in the process, such as using a chemical vapor deposition machine, are required and the process is complicated.

  According to Japanese Patent Laid-Open Publication No. 2006-76855, 2006-172722, a binder-free inorganic paste for low temperature film formation without the use of the above-mentioned equipment was developed, but a method for preparing an inorganic titanium oxide sol, which is a core technology, is not directly described. It is only described that a general sol and gel process is used, and detailed process conditions are not described.

Accordingly, in the present invention, unlike the above methods, in the preparation of low temperature film forming paste, a low temperature process using only a general sol and gel process without using a separate equipment at low temperature is invented, and using the inorganic binder prepared in the above process, the nano It was confirmed through experiments that the titanium oxide paste prepared at a low temperature containing titanium oxide powder was completed and the present invention was completed.

Moreover, the objective is to develop and provide the whole process to the flexible plastic dye-sensitized solar cell module manufactured using said titanium oxide paste.

(1) Preparation of high concentration water soluble titanium oxide-containing inorganic binder sol

 4,

A process for preparing a high concentration water soluble titanium oxide (100) -containing inorganic binder sol is defined as mixing water (10) and titanium alkoxide (20) using a catalyst (30).

, 여기서 R= alkyl group)(20), 가수분해 및 용매로서 증류수(10)를 포함한다. Titanium alkoxide (Titanium alkoxide) is used as a starting material for preparing inorganic binder sol containing a high concentration (oxide content of 8-20 wt%) water-soluble titanium oxide (100).

, Wherein R = alkyl group) 20, hydrolysis and distilled water 10 as a solvent.

 In order to control the viscosity, ethanol (11), ethanol (12), isopropanol (13), buthanol (15), and the like are included as lower alcohol solvents.

 An acid catalyst 30 was used for acid peptization of the precipitate hydrated by hydrolysis of the titanium alkoxide. It is preferable to use nitric acid 31, hydrochloric acid 32, and acetic acid 33 as said acid catalyst.

  To prepare a sol having a concentration of 8.0-20 wt% of sol of titanium oxide (100) relative to the solvent, 20-35 mL of distilled water was placed in a Pyrex flask sealed container and the temperature was adjusted to a temperature of 50-80 ° C using a water bath reactor. Then, 20-30 mL of titanium alkoxide (20) is slowly added. Titanium alkoxide 20 is hydrolyzed as it is added, resulting in a precipitate. Thereafter, 1.0 -5.5 mL of an acid catalyst (here, 60 wt% nitric acid (31) is added, followed by vigorous stirring using a stiller. The stirring time is up to 46-48 hours. The gelation reaction takes place The concentrated titanium oxide sol, which has been titrated, becomes a pale blue viscous sol.

    For example, 25 mL of titanium alkoxide (20) was added to 35 mL of distilled water (10) in a concentration of 14.7 wt% water-soluble titanium oxide (100) sol, and then 2.0 mL of 60 wt% nitric acid (31) was added thereto. Can be prepared by stirring for 2 days. Titanium oxide sol is prepared with a viscous blue sol.

  Figure 5 shows the result of measuring the amount changed over time the viscosity change of the titanium oxide 100 sol of the concentration of 14.7 wt% prepared in the preparation example over time.

  5,

  Viscosity is lowered to about 7 cps after 13 days at 80 cps immediately after preparation, and there is little change in viscosity thereafter.

   5 and 6 show that the concentration of ethanol (12) and water (10) used as a solvent was changed to 12.64 wt%, 14.7 wt%, and 18.4 wt%, respectively. And an average particle diameter.

  6,

 When the titanium oxide (100) sol concentration was 14.7 wt%, the viscosity was the lowest at 6 cps.

  Referring to Figure 7,

  The average particle diameter was 27 nm.

 8 and 9 provide a fixed viscosity of the titanium oxide 100 sol concentration to 14.7 wt% and a change in viscosity and average particle diameter of the sample in which ethanol 12 is increased as a solvent.

 8 and 9,

 As the amount of ethanol (12) increases, the viscosity increases rapidly up to 270 cps, and the average particle size increases to 80 nm. The lower or smaller 14.7 wt% viscosity and average particle diameter than when the titanium oxide 100 sol concentration is 12.64 wt% provide a close relationship with the ethanol 12 concentration used as the solvent.

  In addition, increasing the concentration of ethanol (12) provides a relative dielectric constant lower than that of water in a solvent system composed of water (10) / ethanol (12), and agglomeration of ultrafine particles in the suspension sol, resulting in an increase in viscosity. do.

 10 and 11 show the result of irradiating the crystal phase with a pattern by powder X-ray diffraction analysis after drying the titanium oxide sol prepared in the preparation example.

 With reference to FIGS. 10 and 11,

 When the sol concentration is low and the amount of ethanol in the solvent is high, the rutile crystal phase is not observed.However, as in the case of the 14.7 wt% sol, the sol concentration is high, and the amount of ethanol in the solvent is low and the amount of water is high. Anatase, brookite and rutile crystalline phases are provided to produce.

 Therefore, the titanium oxide sol prepared in the solvent as water / ethanol = 59/41 (wt%) and the concentration of 14.7 wt% was selected as the inorganic binder composition for film formation, and the titanium oxide for low temperature film formation was selected. It is desirable to prepare a (100) paste.

  (2) Preparation of titanium oxide paste for low temperature film formation

   As a solvent, 0-25 mL of acetonitrile was added to 15-25 mL of four solvents such as isopropane, tert-butanone, 2-methoxetanol, and 1-propanol, followed by P-25 (Degussa). 0-0.6 g of 3.0-6.0 g average particle diameter (21 nm) and Nano-Chem. Powder (; average particle diameter 220 nm) were weighed and placed in a polyester vat pre-inserted with zirconia balls for ball milling. 1 hour. 5-10 mL of a titanium oxide (100) sol having a concentration of 14.7 wt% was added thereto, followed by a ball mill for 1-4 hours to prepare a low temperature film-forming paste.

 Titanium oxide (100) paste preparation example 1 for low temperature film-forming;

 Acetonitrile 1.5 mL, P-25 3.0 g, and nano-chem powder 0.6 g were formed on a PET film by a squeeze method in 25 mL of a solvent selected from one of the various solvents, and dried at 120 ° C. for 15 minutes.

   With reference to Figure 12, the sample prepared in Preparation Example 1 of the titanium oxide 100 paste for low temperature film formation

 It is a photograph (magnification 200 times) which observed the film | membrane state with the optical microscope, and the film | membrane state is a state which the crack went after drying.

 Titanium oxide (100) paste preparation example 2 for low temperature film-forming;

  1.5 mL of acetonitrile, 4.5 g of P-25 (130) powder, and 0.6 g of nano-chem powder were formed on a PEN film 150 by 25 mL of 1-propanol and dried at 120 ° C. for 15 minutes.

   With reference to Figure 13, prepared in Example 2 of a low temperature titanium oxide paste for film forming

 The state of the film was observed under an optical microscope (magnification 200 times), and the film state provided a homogeneous state.

   In the present invention, 1-propanol 110 may be used as a solvent for preparing a low temperature titanium oxide 100 paste.

  (3) film formation, pigment impregnation and electrolyte preparation

   In order to manufacture a film type solar cell, a PET or PEN film on which an ITO electrode is deposited is used as a substrate. As a film deposition method on a substrate, a spray or squeeze method is used. A film of 3 cm x 5 cm is deposited on a 200 μm thick ITO-deposited PEN film (up to 13 ohm sheet resistance) and dried at 120 ° C. In the film-form dried film, a pigment | dye is put into the ethanol solution containing R-535-bis-TBA Ruthenium type | system | group pigment | dye, and pigment | dye impregnation is carried out at room temperature for 24 hours.

))을 용매로 LiI 0.1M, I2 0.05M, DMPⅡ(

)0.6M, 4-tert-butylpyridine(TBP,

) 0.5M 농도로 조정하여 상온에서 6시간 혼합하여 제조한다. The electrolyte is methoxy acetonitrile (

)) As solvent LiI 0.1M, I2 0.05M, DMPII (

) 0.6M, 4-tert-butylpyridine (TBP,

) The mixture is adjusted to 0.5M and prepared by mixing at room temperature for 6 hours.

  14 is a process chart of manufacturing a film-type dye-sensitized solar cell titanium oxide (100) paste. The paste 1 (50) process and the paste 2 process 60 differ in the amounts of the P-25 powders 52 and 62, and the following processes are the same. 25 ml of 1-PrOH and 1.25 ml (51, 61) of acetonitrile were mixed, 2.5 g (52) of P-25 powder for paste 1 process, 3.0 g (62) of P-25 powder and 0.6 g of nano chemical for paste 2 process. Mix. The fine mill was pulverized with ball mills 53 and 63 for 1 hour to make sol 54 and 64, and the ball mills 55 and 65 were performed for the final 1 hour.

 The paste 3 (70) process is different from the paste 1 (50) process only in the amount of 1-PrOH (52, 71) mixed and is the same process below. The paste 1 (50) process had 25 ml of 1-PrOH (51) and the amount of 1-PrOH (71) had 18 ml.

)로 측정한 실험 결과이다. 페이스트 2(60)보다 P-25 함량이 높은 페이스트 1의 변환 효율이 2.14%로 높아졌으며, 용매 1-PrOH함량을 18mL로 줄인 페이스트 3(70)의 경우, 변환 효율은 2.58%로 본 실험에서는 최대치를 제공한다. 15 shows an example of measuring conversion efficiency according to a film-type dyeing-stopped solar stop paste manufacturing process chart. Photoelectric conversion efficiency measurement is based on open cell (cell area 0.25)

This is the experimental result measured by). The conversion efficiency of Paste 1, which is higher in P-25 than Paste 2 (60), is 2.14%, and the conversion efficiency is 2.58% for Paste 3 (70), which reduces the solvent 1-PrOH content to 18 mL. Provide the maximum.

 (4) Manufacture of film-type dye-sensitized solar cell module

)을 제조하였다. 이 모듈에 세 파장 형광등(27W)을 조사하였을 때, 흐르는 전류량을 측정하는 전류 값은 21.9 mA이고, 측정 전압은 약 0.72 mV얻었다. As a counter electrode of the film for positive electrodes, PEN film (Pecell Cell, Japan, 180 micrometers in thickness, resistance 5Ω) coated with platinum (Pt) is used. A UV-visible ray hardening resin is used as a sealing agent, and the hole for electrolyte injection is previously made in the counter electrode. After sealing, the electrolyte solution was added and the hole was again sealed with a resin to prepare a prototype module (light receiving area of about 20

) Was prepared. When the three-wavelength fluorescent lamp (27W) was irradiated to this module, the current value for measuring the amount of current flowing was 21.9 mA, and the measured voltage was about 0.72 mV.

   The present invention is to develop a low temperature process using only a typical sol and gel process without using a separate equipment at a low temperature in manufacturing a low temperature film forming paste, unlike the existing methods, and using the inorganic binder prepared as described above A low temperature titanium oxide paste containing a powder was invented, and the titanium oxide film was deposited to develop a flexible plastic dye-sensitized solar cell module manufacturing process.

   Through the present invention, the technology of solar cell material and module manufacturing has been established, and there is an alternative effect of the portable power source as an energy supply type suitable for high oil prices.

    Application of the present invention is expected to increase the use of environmentally friendly and energy-saving film-type oxide solar cells inevitably increase the number of portable electronic devices that require secondary batteries such as mobile phones and toys as ubiquitous portable power supply, Other flexible display oxide electrodes.

 In preparing a high concentration water-soluble titanium oxide-containing inorganic binder sol, titanium alkoxide was added to a water / ethanol mixed solvent, and titrated with an acid catalyst, thereby preparing an inorganic binder for film film without an organic additive. The viscosity of the prepared sol was 6-270 cps and the average particle diameter was 27-80 nm, depending on the water / ethanol ratio, and the identified crystal phases were observed anatase, brookite and rutile.

The production of titanium oxide paste for low temperature film formation was performed by using 1-propaneol as a suitable solvent for the titanium oxide paste prepared above, and establishing conditions for preparing titanium oxide paste that can cope with various low temperature film formation methods by controlling the amount of solvent / powder. It was.

  For film formation, dye impregnation, and electrolyte preparation, a titanium oxide positive electrode was formed using a squeeze method with a light receiving area of 3 cm x 5 cm. After drying at 120 ° C, the film had good film strength.

  In the photoelectric conversion efficiency measurement, the maximum photoelectric conversion efficiency of 2.58% was obtained when the amount of titanium oxide powder, the amount of titanium oxide sol, the type and amount of solvent were adjusted.

 Film-type dye-sensitized solar cell module production When the three-wavelength fluorescent lamp (27W) was irradiated to the prototype module having a light receiving area of about 20 square centimeters, the current value generated was 21.9 mA and the measured voltage was about 0.72 mV.

Figure 1 is Ruthenium-based sensitizing pigment

2 is a general dye-sensitized solar cell module structure

3 is a schematic diagram of the light conversion mechanism

4 is an inorganic binder sol manufacturing process chart

5 is a time-dependent change in the viscosity of the titanium oxide (100) sol having a concentration of 14.7 wt%

Figure 6 is the viscosity change according to the concentration of sol titanium oxide (100)

7 is a particle size change according to the concentration of sol of titanium oxide (100)

8 is a viscosity change according to the amount of ethanol

9 is a change in particle size according to the amount of ethanol

10 is an X-ray diffraction pattern according to the sol concentration

11 is an X-ray diffraction pattern according to the amount of ethanol

12 is an optical micrograph (x200) of a film deposited on a PET film

Figure 13 shows the film formation state of the paste by 1-Propanol solvent

14 is a film dye-sensitized solar cell paste manufacturing process chart

Figure 15 shows the conversion efficiency of the film-type dye-sensitized solar cell paste

Claims (4)

Flexible dye-sensitized solar cell using a low temperature manufactured titanium oxide paste characterized by preparing an inorganic binder for film deposition without adding an organic additive by adding a titanium / alkoxide mixed solvent of water and ethanol, and titrating with an acid catalyst. The method of claim 1, Lower alcohol solvents include ethanol (11), ethanol (12), isopropanol (13), buthanol (15), and the like for adjusting the viscosity.  Low temperature production oxidation characterized by using nitric acid (31), hydrochloric acid (32), acetic acid (33) as acid catalyst (30) for acid peptization of the precipitate hydrated by hydrolysis of the titanium alkoxide. Flexible Dye-Sensitized Solar Cell Using Titanium Paste Flexible dye-sensitized solar cell using a low temperature titanium oxide paste prepared by low temperature film formation method by controlling the amount of solvent / powder using solvent 1-propanol  Titanium oxide positive electrode was formed by spraying or squeeze method, dried at 120 ° C, and then added to pigment-containing ethanol and impregnated at room temperature for drying. The amount of titanium oxide powder, the amount of titanium sol, and the type and amount of solvent were adjusted. Flexible dye-sensitized solar cell using low-temperature manufactured titanium oxide paste for maximum photoelectric change efficiency

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