Methods for Encapsulating Nanocrystals and Resulting Compositions

Abstract

The present invention provides methods for hermetically sealing luminescent nanocrystals, as well as compositions and containers comprising hermetically sealed luminescent nanocrystals. By hermetically sealing the luminescent nanocrystals, enhanced lifetime and luminescence can be achieved.

1 - 20 . (canceled) 
     
     
         21 . A microsphere comprising:
 (a) a central region;   (b) a first layer on an outer surface of the central region, the first layer comprising one or more luminescent nanocrystals; and   (c) a barrier layer on an outer surface of the first layer.   
     
     
         22 . The microsphere of  claim 21 , wherein the central region comprises silica. 
     
     
         23 . The microsphere of  claim 21 , wherein the first layer comprises an inorganic material. 
     
     
         24 . The microsphere of  claim 23 , wherein the inorganic material comprises silica or titania. 
     
     
         25 . The microsphere of  claim 21 , wherein the luminescent nanocrystals are core-shell luminescent nanocrystals. 
     
     
         26 . The microsphere of  claim 25 , wherein the core-shell luminescent nanocrystals are selected from the group consisting of CdSe/ZnS, CdSe/CdS and InP/ZnS. 
     
     
         27 . The microsphere of  claim 21 , wherein the luminescent nanocrystals are between about 1-10 nm in size. 
     
     
         28 . The microsphere of  claim 21 , wherein the barrier layer comprises an inorganic layer. 
     
     
         29 . The microsphere of  claim 28 , wherein the barrier layer comprises SiO 2 , TiO 2  or AlO 2 . 
     
     
         30 . The microsphere of  claim 21 , wherein the microsphere has a diameter of less than about 500 microns. 
     
     
         31 . The microsphere of  claim 30 , wherein the microsphere has a diameter of less than about 10 microns. 
     
     
         32 . The microsphere of  claim 30 , wherein the microsphere has a diameter of less than about 1 micron.