Synthesis of selenium particles with various morphologies

• Stable aqueous dispersions of uniform selenium spheres were prepared.
• The selenium spheres are formed by the aggregation of nanosize subunits.
• The subunits are responsible for the optical properties of selenium particles.
• The spheres can be converted into anisotropic structures by recrystallization.
• The pH and presence of a co-solvent have a major effect on the recrystallization process.

Uniform selenium spherical particles were prepared by reducing selenous acid with hydroquinone in the presence of Daxad 11G. The red colored colloidal dispersions displayed a distinct plasmon band at ∼612 nm and were stable for extended time due to the negative surface potential of the particles. Structural analyses indicated that the Se spheres were aggregates of nanosize subunits crystallized in the hexagonal system. Selenium wires and rods were obtained by changing the pH and the composition of the precipitated dispersions and incubating them for extended time at moderate temperatures. The addition of a co-solvent played a major role in the re-crystallization of selenium spheres into anisotropic structures.

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