Abstract: A method of manufacturing nanoparticles of a photoluminescent material, including the successive steps of: a) forming nanometer-range particles of said photoluminescent material; b) forming a dispersion containing the particles in a non-aqueous solvent, the dispersion further containing at least one surface agent; c) placing the dispersion in an autoclave at a pressure in the range from 2 MPa to 100 MPa; and d) recovering the particles.

Abstract: A method for producing a photo-luminescent material, including the following steps: (1) producing, according to a sol-gel method, a sol and then a gel of first precursors of a first substance from the sol; (2) crushing the gel; (3) optionally, annealing the gel in order to form first particles of the first substance of which the average size is between 1 pm and 20 um; (4) producing a colloidal dispersion of second particles of a second substance, different from the first substance or identical to the first substance, of which the average size is between 5 nm and 400 nm; (5) mixing the colloidal dispersion with the sol in step (1) before forming the gel or with the first particles after step (3); and (6) annealing the mixture obtained in step (5), resulting in an increase in the compactness of the mixture, the average size of the second particles after annealing being between 100 nm and 900 nm.

Abstract: A method of manufacturing nanoparticles of a photoluminescent material, including the successive steps of: a) forming nanometer-range particles of said photoluminescent material; b) forming a dispersion containing the particles in a non-aqueous solvent, the dispersion further containing at least one surface agent; c) placing the dispersion in an autoclave at a pressure in the range from 2 MPa to 100 MPa; and d) recovering the particles.

Abstract: A method for producing a photo-luminescent material, including the following steps: (1) producing, according to a sol-gel method, a sol and then a gel of first precursors of a first substance from the sol; (2) crushing the gel; (3) optionally, annealing the gel in order to form first particles of the first substance of which the average size is between 1 pm and 20 um; (4) producing a colloidal dispersion of second particles of a second substance, different from the first substance or identical to the first substance, of which the average size is between 5 nm and 400 nm; (5) mixing the colloidal dispersion with the sol in step (1) before forming the gel or with the first particles after step (3); and (6) annealing the mixture obtained in step (5), resulting in an increase in the compactness of the mixture, the average size of the second particles after annealing being between 100 nm and 900 nm.

Abstract: The present invention provides a process for preparing a rare earth borate by reacting together at least one rare earth salt, boric acid and a base. The process is characterized in that the reaction is carried out using an excess of acid with respect to the stoichiometry and under conditions such that the pH of the reaction medium at the end of the reaction is in the range of 6 to 8. The precipitate formed is then recovered and calcined. The phase purity of the borate obtained is good and it can be used as a luminophore.