Zinc cadmium sulfide is a mixture of zinc sulfide (ZnS) and cadmium sulfide (CdS). It is used for its fluorescent properties. It is a semiconductor material commonly used in various applications, including optoelectronics, photovoltaics, and as a phosphor in display technologies. It typically exists in two crystalline forms: zinc blende and wurtzite.
Bioaccumulation of this chemical may occur along the food chain, for example in plants and in seafood. Long-term or repeated exposures are expected to have harmful effects on the kidneys, bones, and respiratory tract, resulting in kidney impairment, osteoporosis (bone weakness), and chronic inflammation of the respiratory tract.
Properties
- Chemical Composition: ZnCdS is a ternary compound with variable ratios of zinc to cadmium. Its formula can be expressed as Zn₁₋ₓCdₓS, where 𝑥x varies depending on the specific composition.
- Crystal Structure: It typically crystallizes in the hexagonal wurtzite or cubic sphalerite structure, depending on the proportions of zinc and cadmium.
- Color and Luminescence: ZnCdS is often yellowish-green in color and exhibits photoluminescence, making it useful in optoelectronic applications.
- Band Gap: The band gap energy of ZnCdS can be tuned by adjusting the ratio of Zn to Cd. It ranges from approximately 2.4 eV (for ZnS) to about 2.0 eV (for CdS).
- Solubility: It is slightly soluble in water and can be affected by pH, with solubility increasing in acidic conditions.
Occurrences
- Natural Occurrences: ZnCdS can be found in nature, often in mineral deposits alongside other sulfides.
- Synthetic Production: It is primarily produced synthetically for various applications, including photoconductors, phosphors, and solar cells.
Applications
- Optoelectronic Devices: Used in light-emitting diodes (LEDs) and laser diodes.
- Displays: Acts as a phosphor in cathode ray tubes and other display technologies.
- Solar Cells: Employed in thin-film solar cells for improved efficiency.
Toxicity
Cadmium is a toxic heavy metal, which raises environmental and health concerns regarding the use of ZnCdS.
