Luminescent Composition

Abstract

The invention relates to a luminescent composition which is based on yttrium oxide sulfide and other oxide sulfides and to which at least one doping agent is added. The inventive composition has a characteristic emission spectrum and can optionally be used along with a reading system that is adjusted to the emission spectrum in order to mark substances or substance mixtures.

1 - 23 . (canceled) 
   
   
       24 . A luminescent composition comprising
 (a) an oxide sulfide of yttrium and oxide sulfides of at least three further elements selected from among lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium and   (b) at least one dopant selected from among oxides and fluorides of main group and transition group elements,   
     wherein the further oxide sulfides are selected from among oxide sulfides of erbium, ytterbium and of at least one further element, in particular of lutetium, gadolinium, holmium, thulium, dysprosium and/or europium. 
   
   
       25 . The composition as claimed in  claim 24 , characterized in that yttrium oxide sulfide is present in a proportion of ≧90 mol % based on the total component (a). 
   
   
       26 . The composition as claimed in  claim 24 , characterized in that the further oxide sulfides are present in a proportion of in each case up to 2 mol % based on the total component (a). 
   
   
       27 . The composition as claimed in  claim 24 , characterized in that it contains a fluoride as dopant. 
   
   
       28 . The composition as claimed in  claim 24 , characterized in that it contains an alkaline earth metal and/or a transition group element as dopant. 
   
   
       29 . The composition as claimed in  claim 28 , characterized in that it contains calcium, zinc and/or titanium. 
   
   
       30 . The composition as claimed in  claim 24 , characterized in that the dopants are present in a proportion of in each case up to 5 mol % based on the sum of the components (a) and (b). 
   
   
       31 . The composition as claimed in  claim 30 , characterized in that the dopants are present in a proportion of in each case up to 1 mol % based on the sum of the components (a) and (b). 
   
   
       32 . The composition as claimed in  claim 24 , characterized in that it is in crystalline form. 
   
   
       33 . The composition as claimed in  claim 24 , characterized in that it is present as a single phase. 
   
   
       34 . The composition as claimed in  claim 24  in the form of particles. 
   
   
       35 . The composition as claimed in  claim 34 , characterized in that the average particle size is in the range 1 nm-100 μm. 
   
   
       36 . The composition as claimed in  claim 24  introduced into or applied to a material or a mixture of materials. 
   
   
       37 . The composition as claimed in  claim 36  characterized in that it is present in a proportion of 10-500 ppm in the material or mixture of materials. 
   
   
       38 . The use of a luminescent composition as claimed in  claim 24  for marking materials or mixtures of materials. 
   
   
       39 . The use as claimed in  claim 38 , characterized in that a plurality of different compositions are introduced as mixture or as pattern into the material or the mixture of materials or applied thereto. 
   
   
       40 . The use as claimed in  claim 34 , characterized in that a luminescent composition having a characteristic emission spectrum is detected by means of a reading system matched thereto. 
   
   
       41 . The use as claimed in  claim 34 , characterized in that the composition is excited to luminescence by irradiation with a wavelength in the range of about 850-1500 nm, in particular about 920-1000 nm, and the emitted radiation in a range of 300-1700 nm is detected. 
   
   
       42 . The use of a reading system for detecting a marked material or mixture of materials, comprising:
 (i) a radiation source, preferably a radiation source in the IR range, and   (ii) one or more optical detectors provided for the selective detection of specific emission lines of a luminophor,   
     wherein the material or the mixture of materials is marked with at least one luminescent composition as claimed  claim 24 . 
   
   
       43 . The use as claimed in  claim 42 , characterized in that a plurality of optical detectors are provided for the selective detection of different emission lines. 
   
   
       44 . A material or mixture of materials into which a composition as claimed in  claim 24  has been introduced or applied thereto.