Cadmium phosphide

Cadmium phosphide is an inorganic chemical compound. It is a grey or white bluish solid semiconductor material with a bandgap of 0.5 eV. It has applications as a pesticide, material for laser diodes and for high-power-high-frequency electronics.

Synthesis and reactions

Cadmium phosphide can be prepared by the reaction of cadmium with phosphorus:

Structure

Cd₃P₂ has a room-temperature tetragonal form.
The crystalline structure of cadmium phosphide is very similar to that of zinc phosphide (Zn₃P₂), cadmium arsenide (Cd₃As₂) and zinc arsenide (Zn₃As₂). These compounds of the Zn-Cd-P-As quaternary system exhibit full continuous solid-solution.

Applications

Over the last decade, interest in cadmium phosphide as a source for fast, near-IR emission has grown due to the development of cadmium phosphide quantum dots. Literature has demonstrated that these quantum dots possess tunable emission between 700 nm to 1500 nm. A recent paper investigated the effect of surface passivation on these quantum dots and showed that cadmium phosphide quantum dots may have an intrinsic band-edge relaxation time less than 100 ns.

Safety

Like other metal phosphides, it is acutely toxic when swallowed due to the formation of phosphine gas when it reacts with gastric acid. It is also carcinogenic and dangerous for the skin, eyes and other organs in a large part due to cadmium poisoning.