Researchers from the Institute of Molecular Sciences in collaboration with scientists from the Institute of Chemistry of Condensed Matter of Bordeaux (CNRS) two Thai teams (VISTEC in Rayong and Kasetsart University in Bangkok) have just developed a new process for synthesizing asymmetric semiconductor particles. Such objects promise applications in the field of catalysis and more particularly photosynthesis of water.

Semiconductors

Do you know the particles of Janus? When an electric field is applied to a conductive object placed between two electrodes in a solution – a metal for example – the latter polarizes and acquires opposite charges at its ends. It can then undergo oxidation-reduction reactions, breaking the symmetry of the particle, leaving two distinct faces to appear. A particle of Janus is then obtained in reference to the Roman God with two faces.

This simple process, based on a so-called “wireless” electrochemical concept, makes it possible to synthesize these particles of Janus in large quantities. Problem: This transformation requires, in principle, good electrical conductivity of the particles to be modified which is why semiconductors so far could not be used in this context.

Indeed, researchers at the Bordeaux Institute of Molecular Sciences have subjected semiconductor particles not only to an electric field but also to UV irradiation. The role of light is to excite the electrons of the semiconductor making it more sensitive to the electric field. The polarization and consequently the dissymmetry of the particle can then take place.

The experiment was carried out with, as semiconductor, particles of titanium dioxide (TiO 2) commonly used to manufacture photovoltaic cells among others. Result: bathed in a solution of metallic salt simultaneously subjected to an electric field and irradiation, the particles are transformed and a double face appears one metal side and another side showing no modification.

These new hybrid semiconductor particles are integrated into a very wide field of application, which extends from the field of photo catalysis treatment of water air, antibacterial to cosmetic products. Particles of titanium dioxide (TiO 2) commonly used to make photovoltaic cells, among others.

Result: bathed in a solution of metallic salt, simultaneously subjected to an electric field and irradiation, the particles are transformed and a double face appears one side metallic, and another side showing no modification. These new hybrid semiconductor particles are integrated into a very wide field of application, which extends from the field of photo catalysis (treatment of water, air antibacterial to cosmetic products. Particles of titanium dioxide (TiO 2) commonly used to make photovoltaic cells, among others.

Result: bathed in a solution of metallic salt, simultaneously subjected to an electric field and irradiation, the particles are transformed and a double face appears one side metallic, and another side showing no modification. These new hybrid semiconductor particles are integrated into a very wide field of application, which extends from the field of photo catalysis treatment of water, air, antibacterial to cosmetic products. Subjected simultaneously to an electric field and an irradiation, the particles are transformed and a double face appears one metal side, and another side showing no modification. These new hybrid semiconductor particles are integrated into a very wide field of application, which extends from the field of photocatalysis (treatment of water, air antibacterial to cosmetic products.

Subjected simultaneously to an electric field and an irradiation, the particles are transformed and a double face appears one metal side, and another side showing no modification. These new hybrid semiconductor particles are integrated into a very wide field of application, which extends from the field of photo catalysis treatment of water, air antibacterial to cosmetic products.