TWI421215B - Titanium dioxide gel and its application method - Google Patents

Description

Titanium dioxide gel and application method thereof

The present invention relates to a titanium dioxide gel and a method for using the same, in particular to a titanium dioxide gel having rapid drying characteristics, and using the titanium dioxide gel with carbon dioxide laser as a heating source to produce a titanium dioxide film having broad absorption band optical properties. Methods.

Titanium dioxide film is an important component affecting the light absorption efficiency of solar cells. Currently, methods for preparing titanium dioxide film include composite plating, sol-gel, anodic oxidation, and evaporation. (evaporation), sputtering, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), and atomic layer deposition (atomic layer deposition, ALD), in which the composite plating method, the sol-gel method, the anodizing method and the like have the advantages of simple process and cheap equipment, but the composite plating method coats the photocatalyst oxide in the metal plating layer, so that the catalyst is limited in efficiency. The sol-gel method combines the synthesized titanium dioxide into a solvent gel and coats it on the surface of the substrate to form a film, which is suitable for a substrate with a complicated shape, and the doping composition has high variability, but it has a combination in the process. High temperature sintering and film are easily damaged by external force; anodizing is limited by the low adjustability of coating composition; Plating, chemical vapor deposition, atomic layer deposition, etc. require the use of a vacuum system, the cost of the process equipment is relatively high, and the evaporation and sputtering methods have a poor coating ability to the porous substrate, and the chemical vapor deposition method has The disadvantage of higher reaction temperature; in addition, the current research on the photoelectric properties of titanium dioxide Most of the research directions are limited to the study of the absorption spectrum shift or the influence of different base materials on the spectral absorption. There is no clear study on the wide band absorption spectrum, but how to enhance the absorption band range of the titanium dioxide film to sunlight, and then improve The light absorption efficiency of the overall solar cell should also be one of the key research directions.

It is known that titanium dioxide has three crystal phases of Rutile, Anatase and brookite, among which rutile phase and anatase phase are relatively stable, and it is in titanium dioxide film. The main crystal phase has emerged as one of the main materials for developing photoelectric properties, photocatalyst, dielectric properties and semiconductor properties with high refractive index; usually at 800 ° C under normal pressure, it is a stable phase of rutile phase, atmospheric pressure. Below 800 ° C is the metastable phase of the anatase phase. Some scholars have found that the anatase phase has a higher conversion efficiency after comparing the conversion efficiency of the dye-sensitized solar cell prepared by the pure rutile phase and the pure anatase phase. The conversion efficiency is attributed to the fact that the anatase phase structure can make a large area contact with the dye. Therefore, in addition to the type of pigment selected for the dye-sensitized solar cell, the quality of the titanium dioxide film will become an important key factor.

The present invention provides a quick-drying form and is different from the conventional titanium dioxide gel. By changing the molar ratio of the components in the titanium dioxide gel, the titanium dioxide crystal image in the titanium dioxide film formed by the titanium dioxide gel can be rutile or The phase control of anatase phase can be effectively applied to optical and optoelectronic technology related applications. The titanium dioxide film prepared by using the titanium dioxide gel of the invention has the optical characteristics of a wide absorption band, which is different from the conventional furnace annealing in the physical gas phase. Deposition or chemical vapor deposition produces a thin film of titanium dioxide with a narrow absorption band.

The titanium dioxide gel of the present invention comprises at least the following components: titanium isopropoxide in an amount of from 0.01 to 4 moles; Acetylacetone is added in an amount of 0.01 to 4 moles; ethanol is added in an amount of 0.01 to 10 moles; and water is added in an amount of 0.01 to 30 moles.

Among them, the titanium dioxide gel of the invention has the characteristics of quick drying, and the titanium dioxide film can be obtained after a simple coating step without complicated steps of purification, drying and sintering, so that it can be easily applied to the semiconductor. Manufacture of medium titanium dioxide film.

The invention also provides a method for applying a titanium dioxide gel, which uses a carbon dioxide laser as a thermal energy to heat a test piece coated with a titanium dioxide gel to produce a titanium dioxide film having a wide absorption band optical property, which comprises the following steps: (1) coating gel: applying a titania gel to a test piece; and (2) laser annealing: using a carbon dioxide laser as a heat source, and performing heat annealing on the test piece of step (1), The titanium dioxide gel was allowed to form a film of titanium dioxide having a crystal phase on the test piece.

Wherein, the titanium dioxide gel system comprises at least the following components: titanium isopropoxide, the amount of addition is 0.01 to 4 moles; acetamidine acetone, the addition amount is 0.01 to 4 moles; ethanol, the amount of addition is From 0.01 to 10 moles; and water, added in an amount of from 0.01 to 30 moles: the test piece is a tantalum wafer, ruthenium dioxide or glass.

When performing the carbon dioxide laser heating annealing of step (b), the output energy of the carbon dioxide laser is adjusted to be 0.1 to 10 W, and the scanning speed is 0.1 to 200 mm (mm/s) per second, and the focus position is Maintain a distance of 0 to 10 mm from the test piece.

Accordingly, the titanium dioxide gel of the present invention has the characteristics of quick drying, and the titanium dioxide film can be obtained after a simple coating step without complicated steps of purification, drying and sintering, so that it can be easily applied. a titanium dioxide film produced by using the titanium dioxide gel, wherein the titanium dioxide film is a single crystal phase or a mixed crystal phase and has a wide absorption band (350-730 nm) optical characteristics, and the titanium dioxide gel is adjusted by adjusting The ratio of the components in the middle can control the effect of the rutile or anatase phase in the titanium dioxide film, so the present invention provides a low-cost, fast, simple and high-quality titanium dioxide gel application method, which can be effectively applied. To improve the photoelectric performance of solar cells.

1‧‧‧ The test piece was coated with the titanium dioxide solution of formula 1 and was subjected to heat annealing on the surface of the test piece with a laser beam of laser energy of 0.5 W and a scanning speed of 11.4 mm/s.

2‧‧‧ The test piece was coated with the titanium dioxide solution of formula 2 and was subjected to heat annealing on the surface of the test piece with a laser beam of laser energy of 0.5 W and a scanning speed of 11.4 mm/s.

3‧‧‧ The test piece was coated with the titanium dioxide solution of Formulation III and heat-annealed on the surface of the test piece with a laser beam of laser energy of 0.5 W and a scanning speed of 11.4 mm/s.

4‧‧‧ Test strips coated with titanium dioxide solution but not annealed with carbon dioxide laser

1'‧‧‧ test piece coated with titanium dioxide solution of formula 1 and heat-annealed on the surface of the test piece with a carbon dioxide laser with a laser energy of 3.0 W and a scanning speed of 11.4 mm/s

2'‧‧‧ test piece coated with titanium dioxide solution of formula 2 and heat-annealed on the surface of the test piece with a carbon dioxide laser with a laser energy of 3.0 W and a scanning speed of 11.4 mm/s

The 3'‧‧‧ test piece was coated with the titanium dioxide solution of Formulation III and heat-annealed on the surface of the test piece with a carbon dioxide laser with a laser energy of 3.0 W and a scanning speed of 11.4 mm/s.

The 3'‧‧‧A test piece was coated with the titanium dioxide solution of Formulation III and was heat-annealed on the surface of the test piece with a laser energy of 3.0 W, a scanning speed of 11.4 mm/s and a CO 2 laser with a focusing distance of 4 mm.

The 3'‧‧‧B test piece was coated with the titanium dioxide solution of Formulation III and was heat-annealed on the surface of the test piece with a laser energy of 3.0 W, a scanning speed of 11.4 mm/s and a CO 2 laser with a focusing distance of 2 mm.

The 3'‧‧‧C test piece was coated with the titanium dioxide solution of Formulation III and was heat-annealed on the surface of the test piece with a laser energy of 3.0 W, a scanning speed of 11.4 mm/s and a CO 2 laser with a focusing distance of 0 mm.

4'‧‧‧ Test strips coated with titanium dioxide solution but not annealed with carbon dioxide laser

A‧‧‧ anatase phase

R‧‧‧Rutile

a‧‧‧CO2 laser

b‧‧‧Mirror

C‧‧‧ focusing mirror

D‧‧‧Substrate

The first figure is an X-ray diffraction analysis result of a carbon dioxide laser heating of a laser energy of 0.5 W and a scanning speed of 11.4 mm/s according to an embodiment of the present invention.

The second figure is a fluorescence spectrum analysis result of a carbon dioxide laser heating of a laser energy of 0.5 W and a scanning speed of 11.4 mm/s according to an embodiment of the present invention.

The third figure is an X-ray diffraction analysis result of a carbon dioxide laser heating of a laser energy of 3.0 W and a scanning speed of 11.4 mm/s according to an embodiment of the present invention.

The fourth graph is a fluorescence spectrum analysis result of a carbon dioxide laser heating of a laser energy of 3.0 W and a scanning speed of 11.4 mm/s according to an embodiment of the present invention.

The fifth figure is a schematic diagram of focusing heating using a carbon dioxide laser.

The sixth figure is a schematic diagram of discrete focus heating using a carbon dioxide laser.

The seventh figure shows the X-ray diffraction analysis result of carbon dioxide laser heating at different in-focus positions at a laser energy of 3.0 W and a scanning speed of 11.4 mm/s according to the first embodiment of the present invention.

The titanium dioxide gel of the present invention is applicable to the manufacture of a semiconductor titanium dioxide film having Quick drying characteristics, after a complicated step without purification, drying and sintering, a thin coating film can be obtained after a simple coating step, and at least includes the following components: titanium isopropoxide, the amount of addition is 0.01 to 4 moles; acetamidine, added in an amount of 0.01 to 4 moles; ethanol in an amount of 0.01 to 10 moles; and water in an amount of 0.01 to 30 moles.

The application method of the titanium dioxide gel of the present invention comprises the following steps: (1) coating a gel: coating a titania gel on a test piece; and (2) laser annealing: using a carbon dioxide laser as a The heat source is subjected to heat annealing on the test piece of the step (1) to form a titanium oxide film having a crystal phase on the test piece.

Wherein, the titanium dioxide gel system comprises at least the following components: titanium isopropoxide, the amount of addition is 0.01 to 4 moles; acetamidine acetone, the addition amount is 0.01 to 4 moles; ethanol, the amount of addition is At 0.01 to 10 moles; and water, the amount added is between 0.01 and 30 moles.

The test piece is a wafer, ruthenium dioxide or glass.

When performing the carbon dioxide laser heating annealing of step (b), the output energy of the carbon dioxide laser is adjusted to be 0.1 to 10 W, and the scanning speed is between 0.1 and 200 mm (mm/s) per second, and the focus position is compared with the test. The film is kept at a distance of 0 to 10 mm, and the scanning mode of the carbon dioxide laser is not correct. The straight contour is scanned, and the asymmetric straight contour scan is a right angle turn scan.

By using the titanium dioxide gel application method of the present invention, a titanium dioxide film having a thickness ranging from 1 nanometer (nm) to 20 micrometers (μm) and having a visible light absorption range of 350 to 730 nm can be formed on the test piece, even more The crystal phase of titanium dioxide in the formed titanium dioxide film is controlled by adjusting the molar ratio of the components in the titanium dioxide gel, and a titanium dioxide film having a wide absorption band optical property is produced as an application in the field of optics and optoelectronics.

Effect of titanium dioxide gel formulation

The titanium dioxide gel component was mixed according to the ratio of Table 1, and the titanium dioxide gel was coated on a glass test piece by a spin coater to output an energy of 0.5 W and a scanning speed of 11.4 mm per second (mm/s). The carbon dioxide laser is scanned, and the X-ray diffraction analysis result and the fluorescence spectrum analysis result are shown in the first figure and the second figure. In the present embodiment, the water system is added with deionized water, wherein the label is 1 indicates that the test piece is coated with the titanium dioxide solution of the formula and is heated and annealed at a distance of 4 mm from the surface of the test piece with a carbon dioxide laser having a laser energy of 0.5 W. 2 indicates that the test piece is coated with the titanium dioxide solution of the formula II and The surface of the test piece is heat-annealed with a carbon dioxide laser having a laser energy of 0.5 W. The reference numeral 3 indicates that the test piece is coated with the titanium dioxide solution of the formula three and is separated from the surface of the test piece by a carbon dioxide laser having a laser energy of 0.5 W. Heat annealing was performed at a millimeter, and reference numeral 4 indicates that the test piece was coated with a titanium oxide solution but was not annealed by a carbon dioxide laser.

As can be seen from the figure, the titanium dioxide film produced by Formulation 1 has a broad visible light absorption range (350-700 nm), and when the proportion of titanium isopropoxide contained in the titanium dioxide gel rises, it is formed by the method of the present invention. The crystal phase of the titanium dioxide film approaches the anatase phase (shown by the mark A in the figure), and when the proportion of deionized water rises, the crystallinity of the titanium dioxide film is weak, and the crystal phase of the titanium dioxide film is in the rutile phase (in the figure) The mark R is mainly shown, so that the state of the crystal phase in the formed titanium oxide film can be controlled by the adjustment of the composition of the titanium dioxide gel.

The effect of carbon dioxide laser energy

Referring to the first to fourth figures, the titanium dioxide gel component is mixed according to the ratio of Table 1, and the titanium dioxide gel is coated on a glass test piece by a spin coater to output an energy of 0.5 W. Or a 3.0W, scanning speed of 11.4 mm (mm / s) of carbon dioxide laser scanning.

Wherein the reference numeral 1' indicates that the test piece is coated with the titanium dioxide solution of the formula 1 and is subjected to heat annealing on the surface of the test piece with a carbon dioxide laser having a laser energy of 3.0 W, and the numeral 2' indicates that the test piece is coated with the titanium dioxide of the formula II. The solution was heated and annealed at a distance of 4 mm from the surface of the test piece with a laser energy of 3.0 W of laser energy. The reference numeral 3' indicates that the test piece was coated with a titanium dioxide solution of Formulation III and a CO 2 laser with a laser energy of 3.0 W. Heat annealing was performed 4 mm from the surface of the test piece, and reference numeral 4' indicates that the test piece was coated with a titanium oxide solution but was not annealed by a carbon dioxide laser.

Table 2. Table of test conditions for investigating the effect of carbon dioxide laser energy on the method of the present invention

As can be seen from the figure, after the steel sheet coated with the titania gel is subjected to heat annealing using a laser energy of 3.0 W, the crystal phase of the formed titanium dioxide film is rutile phase (R), when the laser output is The energy is raised upwards and the relative surface temperature is also increased. Compared with the formula 2, the titanium dioxide gel of the formula has a higher ratio of titanium isopropoxide, so the relative energy intensity is increased, and the formed titanium dioxide is formed. The film has a stable and broad absorption capacity for visible light having a wavelength between 350 and 730 nm, and the relative energy intensity is also increased with an increase in the proportion of titanium isopropoxide.

Analysis of the X-ray diffraction spectrum of titanium dioxide film shows that the increase or decrease of alcohol content affects the crystallinity of the titanium dioxide film, so that the formed titanium dioxide film is crystallization of the rutile phase in the (110) direction, and the excessive solvent in the titanium dioxide gel causes titanium. The ions are too thin, which indirectly affects the crystallization characteristics of the titanium dioxide film, so that the formed titanium dioxide film lacks the main crystalline phase, and the increase of titanium ions in the titanium dioxide gel can enhance the crystallization characteristics of the titanium dioxide film. In the low wattage power output environment, the same processing conditions The titanium dioxide phase selection (rutile phase or anatase phase) can be controlled by the mixing ratio change, that is, the crystal phase of the titanium dioxide film is brought close to the anatase item by increasing the proportion of titanium isopropoxide.

Laser focus distance effect

Please refer to the fifth and sixth figures. After mixing the titanium dioxide gel components according to the ratio of Table 3, the titanium dioxide gel is coated on a glass test piece by a spin coater to output energy of 3W and scan. The CO2 laser with a speed of 11.4 mm (mm/s) per second was scanned 6 times to compare the effect of laser focusing on the production of carbon dioxide film. The spot size and relative energy intensity can be controlled at different focus positions. Larger energy feedback and higher surface treatment temperature (focus) can be obtained on the surface of the sheet, while the relative energy of the surface of the test piece is smaller and the surface treatment temperature is lower when the focus position moves above the surface of the test piece (discrete Focusing), after performing carbon dioxide laser heating annealing, X-ray diffraction analysis is performed by D/max wide-angle diffractometer, and fluorescence spectrum analysis is performed. The label 3'B test piece is coated with the titanium dioxide solution of the formula 3 and is subjected to heat annealing on the surface of the test piece with a laser energy of 3.0 W, a scanning speed of 11.4 mm/s, and a carbon dioxide laser with a focusing distance of 2 mm; The label 3'A test piece is coated with the titanium dioxide solution of formula III and is subjected to heat annealing on the surface of the test piece with a laser energy of 3.0 W, a scanning speed of 11.4 mm/s, and a carbon dioxide laser with a focusing distance of 4 mm; 4' is the test piece without the laser annealing of the formula 3; the 3'C test piece is coated with the titanium dioxide solution of the formula 3 and has a laser energy of 3.0 W, a scanning speed of 11.4 mm/s and a carbon dioxide with a focusing distance of 0 mm. The result of the thermal annealing of the laser on the surface of the test piece; the reference a is a carbon dioxide laser, the reference b is a mirror, the reference c is a focusing mirror, and the reference d is a substrate.

Please refer to the seventh figure. When the defocus distance is increased, a more stable titanium dioxide film structure can be obtained. This type of carbon dioxide laser can etch the oxide material. When the spot is focused on the surface of the test piece, a large input energy can be obtained. The structure of the titanium dioxide film also has considerable damage. The focus spot change also indirectly changes the spot size, which can make the laser spot have overlapping effect and obtain a more stable crystal structure. The crystal direction obtained by this parameter is the rutile phase (R) crystal which is mainly in the (110) direction.

In summary, the titanium dioxide gel of the present invention has the characteristics of quick drying, and the titanium dioxide film can be easily obtained after a simple coating step without complicated steps of purification, drying and sintering. Used in the manufacture of titanium dioxide thin films in semiconductors, and by controlling the molar ratio of the components in the titanium dioxide gel to control the titanium dioxide rutile or anatase crystal phase in the formed titanium dioxide film to produce a broad absorption band optical property. The titanium dioxide film is used for the application in the field of optics and optoelectronics. The titanium dioxide film prepared by using the titanium dioxide gel in the invention has an absorption band of 350-730 nm, which is different from the conventional furnace annealing in physical vapor deposition or chemistry. Vapor deposition to form a narrow absorption band of titanium dioxide film, in addition, the method of the present invention can also carry out large-area coating operation at room temperature, the formed titanium dioxide film has a large area coating and is different from the traditional process The invention provides a low-cost, fast and simple titanium dioxide gel application method. Applied Optics and effectively applicable to the related art of the photoelectric technology.

1‧‧‧ The test piece was coated with the titanium dioxide solution of formula 1 and was subjected to heat annealing on the surface of the test piece with a laser beam of laser energy of 0.5 W and a scanning speed of 11.4 mm/s.

2‧‧‧ The test piece was coated with the titanium dioxide solution of formula 2 and was subjected to heat annealing on the surface of the test piece with a laser beam of laser energy of 0.5 W and a scanning speed of 11.4 mm/s.

3‧‧‧ The test piece was coated with the titanium dioxide solution of Formulation III and heat-annealed on the surface of the test piece with a laser beam of laser energy of 0.5 W and a scanning speed of 11.4 mm/s.

4‧‧‧ Test strips coated with titanium dioxide solution but not annealed with carbon dioxide laser

Claims (7)

A method for producing a titanium dioxide film, comprising at least the following steps: (1) coating a gel: coating a titanium dioxide gel on a test piece, wherein the gel comprises an addition amount of 0.01 to 4 m Titanium isopropoxide, acetonitrile acetone added in an amount of 0.01 to 4 moles, ethanol added in an amount of 0.01 to 10 moles, and water added in an amount of 0.01 to 30 moles; and (2) laser annealing Using a carbon dioxide laser as a heat source, the test piece of step (1) is subjected to heat annealing, so that the titanium dioxide gel forms a crystalline phase of titanium dioxide film on the test piece, wherein the laser has a range of 0.1 to 10 W. The output energy, a scanning speed of 0.1 to 200 mm per second (mm/s), and a focus position that maintains a distance of 0 to 10 mm from the test piece. The method of producing a titanium dioxide film according to claim 1, wherein the test piece is a wafer, ruthenium dioxide or glass. The method for producing a titanium dioxide film according to claim 1 or 2, wherein the titanium oxide gel component titanium isopropoxide: acetonitrile:ethanol:water has a molar ratio of 2:1:3: 15. The titanium dioxide film formed has a single or mixed crystalline phase. The method of producing a titanium dioxide film according to claim 1, wherein the carbon dioxide laser system performs linear contour scanning in an asymmetric manner. The method for producing a titanium dioxide film according to claim 1, wherein the titanium dioxide film has a thickness of from 1 nanometer (nm) to 20 micrometers (μm). The method for producing a titanium dioxide film according to claim 1, wherein the titanium dioxide film has a visible light absorption range of from 350 to 730 nanometers (nm). A method of producing a titanium dioxide film according to claim 1, wherein the carbon dioxide laser is a right angle turn scan.