JPH03288134A - Recording method - Google Patents

Abstract

PURPOSE:To improve decoloring and coloring by light and decoloring and coloring sensitivity by simultaneously subjecting the color developing layer of an opto-electrochemical element to the impression of an electrochemical oxidation o reduction potential and photoirradiation. CONSTITUTION:After transparent electrodes consisting of ITO, etc., are formed on a transparent substrate consisting of glass, etc., the color developing layer of a transition metal oxide is formed by a vapor deposition method to form a coloring developing substrate. The transition metal oxide is exemplified by WO3, MoO3, etc. The color developing layer of the opto-electrochemical element having the color developing layer contg. the transition metal oxide in such a manner is simultaneously subjected to the impression of the electrochemical oxidation or reduction potential and the photoirradiation. Thereby, the photoelectric current direction is controlled by the impressed potential, the coloring and decoloring by light are executed in this way and the high-density coloring and high-sensitivity coloring and decoloring are executed by the synergistic effect of light and oxidation or reduction current.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a recording/erasing method for a photoelectrochemical device.

Conventional technology As an element utilizing photochromism of transition metal oxides, for example, an optical recording element capable of reversibly decoloring and developing
211848) has been proposed.

This is ``light with energy greater than the band gap of the transition metal oxide (light including light with a wavelength less than the intrinsic absorption edge)''.
This method utilizes optical writing and electrochemical erasing using a photoelectrochemical phenomenon. Characteristics include optical mode (non-thermal mode) recording and electrical erasing, and has memory and reversibility.

Problems to be Solved by the Invention When considering the realization of a large-area rewritable display element that takes advantage of the reversibility, memory properties, and good display quality of the electrochemical coloring phenomenon of transition metal oxides, it is important to consider the photochromism phenomenon. The recording method used has the following problems: (1) it cannot be erased by light; (2) the sensitivity to color development by light is low (color density is low);

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording method that improves color decolorization and color development by light, color development density, and color decolorization sensitivity.

Means for Solving the Problems In a photoelectrochemical element having a coloring layer containing at least a transition metal oxide, a recording method characterized in that applying an electrochemical oxidation or reduction potential to the coloring layer and irradiating it with light are performed simultaneously. It is.

By simultaneously applying an electrochemical oxidation or reduction potential and irradiating light, the direction of photocurrent can be controlled by the applied potential, making it possible to develop and decolorize with light.

Also, due to the synergistic effect with light and oxidation or reduction current,
High-density color development and high-sensitivity color decolorization are possible.

Therefore, control of decolorization and development by light and high density color development are realized.

Example First, the materials and structure will be explained.

A coloring layer containing at least a transition metal oxide is generally formed as follows.

1) After forming a transparent electrode such as TO on a transparent substrate such as glass, a transition metal oxide coloring layer is deposited on a transparent substrate of about 0.00% by vapor deposition. 1~
It is formed to a thickness of 4 μm and used as a coloring substrate.

Transition metal oxides include WO3, MOO3, v206, Ti
O2, Nb2O5, and the like are not particularly limited, but W O3 and M o O3 are particularly excellent in decoloring and developing properties in photochromism and electrochromism.

Further, the transition metal oxide does not need to be used alone, and a mixed film may be used.

The method for forming a thin film of a transition metal oxide is not limited to the vapor deposition method, but may also be a sputtering method, a coating method, or the like.

The transparent substrate is made of glass or various plastics, and the transparent electrode is generally a thin film of In2O3, SnO2, Au, or the like.

Furthermore, when light is irradiated from the coloring layer side, the substrate or electrode on which the transition metal oxide coloring layer is formed does not necessarily have to be transparent.

The color-decoloring process is performed by forming an electrode on a substrate and forming a color-forming layer thereon, with the color-forming layer of the color-forming substrate facing a counter electrode via an electrolyte.

The electrolyte may be a liquid electrolyte or a solid electrolyte. Furthermore, in the case of a liquid electrolyte, the solvent may be water or an organic solvent.

H+, Li, N,
The presence of Na″″K (″ in the electrolyte means that
Transition metal oxides are preferred from the viewpoint of decoloring and developing properties, and among them, Hl is particularly preferred because it has particularly high decoloring and developing sensitivity.

The counter electrode material is not particularly limited, and a counter electrode reaction layer such as a metal hydroxide may be present on the counter electrode.

The coloring substrates used in the examples were all glass substrates on which an ITO transparent electrode (approximately 20Ω/hole) was deposited over the entire surface, and then tungsten oxide or molybdenum oxide was deposited to a thickness of approximately 2 μm.

The recording method will be explained below.

Example 1 A molybdenum oxide coloring substrate on which a patterned transparent electrode was formed and a platinum electrode were mixed with 0 to 1 M/l of lithium perchlorate.
Dissolved propylene carbonate (unrefined, contains water)
When irradiated with mercury lamp light while performing cyclic portammetry at 10 mV/sec in a dark place, it was found that in the reduction (coloring) potential range of molybdenum oxide, light irradiation caused an increase in reduction current and oxidation ( In the decolorizing) potential range, a significant increase in oxidation current was observed upon light irradiation.

That is, by simultaneously applying electrochemical oxidation or reduction potential and light irradiation, the sensitivity to decolorization and color development was improved, and by controlling the applied potential, color development and decolorization by light irradiation could be realized.

Example 2 In place of the molybdenum oxide coloring substrate in Example 1,
A tungsten oxide coloring substrate was used, and the coloring substrate and platinum electrode were immersed in the propylene carbonate solution of Example 1.

First, after electrochemically bringing the entire surface of this coloring layer into a sufficiently decolorized state, 1/10 of the peak value of the reduction current in Example 1 was applied.
Applying a reduction rising potential equal to the current value of and wavelength 80
When irradiation with a semiconductor laser beam of 0 nm and output of 10 mW was performed for 5 seconds at the same time, only the irradiated spot developed a deep color, while the non-irradiated area did not develop a slight color.

Next, after electrochemically bringing this coloring layer into a sufficiently colored state over the entire surface, 1/1 of the peak value of the oxidation current in Example 1 was applied.
Applying an oxidation rising potential equal to a current value of 0 and a wavelength of 8
When irradiation with a semiconductor laser beam of 00 nm and output of 10 mW was performed for 5 seconds at the same time, only the irradiated spot was decolored and the non-irradiated area remained almost unchanged.

In other words, by applying voltage and irradiating light at the same time, a recording method can be obtained in which only the areas irradiated with light are selectively colored or decolored by the applied potential, and coloring and decoloring by light can be realized, and color development sensitivity and color decolorization can be achieved. Achieved improved decolorization sensitivity.

Example 3 A tungsten oxide substrate on which a patterned transparent electrode was formed was used instead of the tungsten oxide coloring substrate of Example 2, and the coloring substrate and platinum electrode were immersed in the propylene carbonate solution of Example 1.

When applying a reduction rising potential equal to a current value of 1/10 of the peak value of the reduction current in Example 1 and irradiating the entire surface with mercury lamp light for 5 seconds at the same time, only the patterned electrode part developed a deep color and other parts There was almost no color development in the area.

When coloring was performed at the same potential and time without irradiation with light, the patterned electrode portion was only slightly colored.

In other words, by applying voltage and irradiating light at the same time, only the parts to which voltage is applied will selectively develop color, and the parts that were irradiated with light but not voltage applied, and the parts to which voltage was applied but not irradiated with light, will develop color. We found a recording method that does not.

Effects of the Invention In a photoelectrochemical device having a coloring layer containing at least a transition metal oxide, there is provided a recording method characterized in that application of an electrochemical oxidation or reduction potential to the coloring layer and light irradiation are performed simultaneously. By controlling the potential,
Discoloration and color development by light, improvement in color density, and improvement in color decolorization sensitivity are realized.

Claims (5)

[Claims] (1) A recording method, in a photoelectrochemical device having a coloring layer containing at least a transition metal oxide, comprising simultaneously applying an electrochemical oxidation or reduction potential to the coloring layer and irradiating it with light. (2) The recording method according to claim 1, characterized in that electrochemical oxidation or reduction potential is applied to the entire surface of the device, and light irradiation is performed to a part of the device surface. (3) The recording method according to claim 1, wherein the electrochemical oxidation or reduction potential is applied to a part of the element surface, and the entire surface of the element is irradiated with light. (4) The transition metal oxide is at least one of tungsten oxide and molybdenum oxide,
The recording method according to claim 1. (5) Electrochemical oxidation or reflux potential application and simultaneous irradiation with light are performed in an electrolyte containing at least one type of cation among H^+, Li^+, Na^+, and K^+. The recording method according to claim 1, wherein: