The invention relates to a compound based on at least one element A chosen from
alkaline-earth metals, on at least one element B chosen from aluminium, gallium
and indium, on sulphur and on a dopant capable of giving the compound luminescence
properties, which is characterized in that it is in the form of a mixture of predominantly
an AB2S4-type crystallographic phase and a B2S3-type
crystallographic phase. This compound is prepared by a method in which a solution
or suspension comprising salts or sols of the elements A, B and of the dopant is
formed in a proportion such that the B/(A+dopant) atomic ratio is at least 2.06;
the solution or suspension is spray-dried; the product thus obtained is sulphurized.
This compound may be used as a phosphor, especially in cathodoluminescence.