Cadmium Sulphide Uses, Applications & Benefits

Cadmium sulfide, Molecular formula CdS, with a molecular weight of 144.46, is an N-type photoconductive semiconductor material. It belongs to group Ⅱ-Ⅵ compound semiconductor. There are crystals and amorphous objects. There are two kinds of crystals: α-type, lemon yellow powder, density 3.91 ~ 4.15; β-type, orange red powder, density 4.48 ~ 4.51. It is found in nature in hexagon crystals with a density of 4.82. It can sublimate in nitrogen. Slightly toxic, non-radioactive, slightly soluble in water and ethanol, soluble in acid, easily soluble in ammonia. The band gap width is 2.41 electron volts, the electron and hole mobility are 2×10-2 and 2×10-3 m 2/ volt · s, respectively, and the relative dielectric constant is 11.6. Used for fireworks, glass glazes, porcelain glazes, luminous materials, and used as paint, paper, rubber and glass pigments (Cadmium yellow and Cadmium red). High purity is a good semiconductor, from hydrogen sulfide into cadmium salt acid solution, the formation of precipitation, after filtering, washing, drying and. The cadmium sulfide solubility product is 3.6×10^-29.

The outstanding advantage of cadmium sulfide photoconductor is the large potential difference of electrostatic potential image and the large contrast of photocopied image. With insulation film on the surface, the wear resistance of the photoconductor is good. Because of its high sensitivity to light, it can be used in machines of all speeds. However, the insulating film on the surface of the photoconductor has some effect on the resolution of the image. Cadmium sulfide is very sensitive to temperature, and is afraid of moisture, because there is no protective film on its surface, it is not good for the operator's body, and is not conducive to the treatment of waste photoconductor, so it is used less and less at present.

Since cadmium sulfide is not easy to be made into single crystal, it has entered the practical stage earlier than germanium, silicon and gallium arsenide, but it has not been studied deeply, and its polycrystalline sintered body and thin film are mostly used. Cadmium sulfide is a sensitive N-type photoconductance device material as well as a piezoelectric device material. It and zinc sulfide solid solution can be made laser wavelength of (3300 ~ 4900) ×10-10 meters laser; The solid solution with cadmium selenide can be made into laser wavelength of (4900 ~ 6750)×10-10 meters; Thin-film heterojunction solar cells made with cadmium telluride are less than 10% efficient, but they are cheap and can be made into large-area devices.

Physicochemical properties of cadmium sulfide

CAS: 1306-23-6

EINECS: 215-147-8

Chemical formula: CdS

Molecular weight: 144.476

Density: 4.82 g/mL at 25 °C(lit.)

Melting point: 980°C (subl.)

Boiling point: 980°C (estimate)

Flash point: 4 °C

Solubility: insoluble

Storage condition: 2-8°C

Appearance: form powder color Yellow to orange

Application: It is used to color enamel, glass, ceramics, plastics, and paints

Cadmium sulfide production

1. The CdS precipitation of cubic crystals can be obtained by passing H2S gas into a hot solution of cadmium perchlorate acidified with a little perchlorate or an aqueous solution of cadmium sulfate acidified with sulfuric acid.

2. After cadmium chloride is acidified with hydrochloric acid, thioacetamide is added, and the solution is heated to produce precipitation. CdS obtained by this method is doped with halogen ions, and these impurities cannot be removed in the process of washing products. The resulting CdS are hexagonal crystals containing halogen ions.

Application of cadmium sulfide

Pigments, soap pigments, yellow glass, fabric, paper and rubber coloring, printing and dyeing inks, ceramic glazes, phosphors and phosphor screens, scintillation counters, photoconductors, semiconductors.

High-purity cadmium sulfide is widely used in solar cells, semiconductor materials, photoelectric devices in the visible light band, automatic camera control illuminometers, photoconductive drums, laser modulation, visible light detectors, laser window materials, infrared two-color detectors, photoluminescence, electroluminescence , The manufacture of cathode ray luminescent materials and pigments, etc.

Operational disposal and storage of cadmium sulfide

Precautions: In closed operation, pay attention to ventilation. Operators must be specially trained and strictly follow the operating procedures. It is recommended that operators wear self-priming filter type dust mask, chemical safety protective glasses, protective clothing, and rubber gloves. Avoid dust. Avoid contact with oxidants and acids. Handling should be light, to prevent damage to the packaging and containers. Equipped with leakage emergency treatment equipment. Empty containers may retain harmful substances.

Storage precautions: Store in a cool, ventilated warehouse. Keep away from fire and heat source. Should be separated from oxidants, acids, etc., do not mix storage. The storage area shall be equipped with suitable materials to hold the leakage.