Extremely fine grained luminescent materials - obtd by fractional sedimentation, using polar organic solvent contg. multivalent cations

摘要

The finest grains of luminescent material and the finest grained layers of the material are obtd. by suspending the initial luminophore powder in a medium and separating the coarse fractions by sedimentation. A polar organic solvent is used in which the luminophore, a small amt. of water, and a small amt. of the salts of multivalent cations are distributed. The polar organic solvent is pref. an alcohol of low molecular wt., esp. isopropanol and the cations Mg2+, Ca2+, Sr2+, La2+, Al3+, and/or Zr4+. The suspension pref. contains per litre, 2.5-10g of luminophore, 10-50 cm3 of water and 2.5-40 mg cations.