JPS6110011A - Production of photoconductive cadmium selenide - Google Patents

Abstract

PURPOSE:To improve the response, output, and signal-to-noise ratio of a photoconductive cadmium selenide obtained by the calcination of raw material, by treating the calcined produce with an organic solvent. CONSTITUTION:Unprocessed CdSe powder is calcined and crystallized to obtain photoconductive CdSe powder having particle diameter of about 1-5mu. The photoconductive CdSe is added to an organic solvent (capable of dissolving selenium, e.g. carbon disulfide, benzene, etc.), stirred at about 25-75 deg.C for about 0.2-1hr, filtered, and dried. The obtained final product is suitable as a raw material for the manufacture of an imaging device element.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to photoconductive cadmium selenide (hereinafter referred to as CdSe).
More specifically, the purpose is to provide a photoconductive material, particularly photoconductive CdSe with high output and high signal-to-noise ratio for use in imaging devices.

(Prior Art) Conventionally, CdS, Se, amorphous Si, etc. have been developed as photoconductive materials for imaging devices in OA equipment such as facsimiles. , and high power and high signal-to-noise ratio photoconductive materials are required to ensure readout.

(Problem to be solved by the invention) Currently, CdS, amorphous S1 or CdS
For example, CdS
has an extremely slow response speed, and Alphas Si has the drawback of not having a sufficient signal-to-noise ratio. CdS is a promising material, but its production involves secondary calcination, secondary calcination, or tertiary calcination as necessary, during which various activators and fluxes are mixed to increase the photoconductivity of CdSe. However, due to the complicated manufacturing method, it is not possible to obtain constant quality, and the S/N ratio and output necessary and sufficient for use in imaging devices cannot be obtained.

(Means for Solving the Problem) As a result of intensive research to solve the above-mentioned drawbacks of the conventional technology, the present inventor discovered that the cause of the instability and low performance of conventional photoconductive CdSe was during manufacturing. It was discovered that this is because free selenium and various other impurities that are generated surround the photoconductive CdSe particles and cannot be removed by post-firing treatments such as washing with water in the prior art. The present invention was completed based on the finding that by performing the treatment with an organic solvent, not only the drawbacks of the prior art were solved, but also the output and signal-to-noise ratio of CdSe were unexpectedly improved.

That is, the present invention provides photoconductive CdSe obtained after firing.
Photoconductive CdS characterized by treating with an organic solvent
This is the manufacturing method of e.

To explain the present invention in detail, the photoconductive CdSe used in the present invention is obtained by obtaining CdSe raw powder from various cadmium salts and selenium or selenium compounds in the same manner as in the prior art, and converting the raw powder into a conventionally known method. For example, the raw powder is mixed with an activator and a flux, and treated at a high temperature to cause diffusion of the activator and C.
A first calcination step to crystallize dSe, a second calcination step to diffuse halogen as a co-activator, a tertiary calcination step to be carried out as necessary, or various modified horn methods thereof. The photoconductive CdSe used in the method of the present invention is not limited to these methods and may be obtained by any method, but the most preferable one is that the particle size is about It is fired and crystallized to about 1 to 5 μm.

According to the inventor's detailed research, the photopic output of these conventional photoconductive CdSe is as follows under the conditions described in the Examples below.
Approximately 0.5 to 100 mV (load resistance IKΩ),
The dark output is about 0.1-11-1O0 (10 MΩ), and the sono-S/N ratio is about lo' to about 10.

The method of the present invention is characterized in that the photoconductive CdSe after firing as described above is treated with an organic solvent. The organic solvent used in the present invention is preferably an organic solvent that can dissolve selenium, and specifically, a 44-mer solvent such as carbon disulfide or benzene.

These solvents can be used alone or in mixtures, but S
Due to the solubility of impurities such as e, it is better to use them alone, and any amount may be used as long as the impurities can be removed.

According to detailed research by the present inventor, when an appropriate amount of photoconductive CdSe is added to an organic solvent, the temperature of about 0.2
This is done by stirring for ~1 hour, filtering, and drying.

(Function/Effect) The photoconductive CdSe of the present invention obtained as described above has an improved response speed as shown in the following implementation compared to the photoconductive CdSe obtained by the conventional method. At the same time, the output of famous spots has been greatly improved, and the signal-to-noise ratio has been significantly improved. Therefore, the photoconductive CdSe of the present invention is extremely useful as an element for imaging devices, and is also useful as a photosensitive material for various devices to which these are applied, such as facsimile machines, laser printers, and input devices for computers.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples. Note that "%" or "%" in the text is based on weight.

Example 1 Take the Cd5el O0 part that has not been imparted with photoconductivity.

100 parts of pure water, 5 to 5 parts of CDC+2O, and 0.0 parts
1 to 0.3 parts of CaCl,.2 H2O was mixed well with 200 parts of dissolved aqueous solution of CaCl, filtered and boiled at 120'O.
Let dry for at least 2 hours. Next, take 100 parts of this dried CdSe, put it in a quartz tube, fully exchange Ni, and
Bake at ~800°C for 30 minutes or more. The obtained powder was ground in a glass ball mill for 0.5 to 2 hours, the loosely sintered parts were loosened, and passed through a 500 mesh sieve.
Wash well with pure water, treat with CdCl□ solution in the same manner as above, filter, and dry at 120° C. for 12 hours or more. 100 parts of the CdSe thus obtained are taken for reheating. Put this in a quartz tube, and add enough N and l.
It was tested, baked at 400-600°C for 30 minutes or more, loosened lightly with a homomixer, passed through a 500 mesh sieve, washed with water for 2 minutes, and prepared with 99 parts of photoconductive Cd5et-
Obtained.

Next, 100 parts of carbon disulfide was added to the resulting photoconductive CdS.
Add to e and stir thoroughly with a stirrer. Then filter,
It was dried at 120° C. for 12 hours or more. The photoconductive Cd5elO portion thus obtained was mixed with 3 parts of a 5:l mixture of styrenic resin and toluene, applied to a comb-shaped aluminum evaporated electrode at a thickness of 100 gm, and dried at 120 °C. After that, the photoconductive properties were measured, and the results shown in Table 1 were obtained.

Example 2 Photoconductive CdSe obtained by firing in the same manner as in Example 1 is placed in 100 parts of benzene, thoroughly mixed with a stirrer, filtered, and then dried.

The photoconductive CdSe of the present invention thus obtained is
When the photoconductive properties were measured in the same manner as in Example 1, the results shown in Table 2 were obtained.

Fat 41EmuL- (+aV). (Pus V) No treatment 95 54 17.59
Is there 0 processing? 50 88 85,
230・Light source 695n・Light amount GOlux・Applied voltage 80 V

Claims (2)

[Claims] (1) A method for producing photoconductive cadmium selenide, which comprises treating the photoconductive cadmium selenide obtained after firing with an organic solvent. (2) The manufacturing method according to claim (1), wherein the organic solvent is selenium-soluble.