Quantum Dot White and Colored Light Emitting Devices

Abstract

A light-emitting device comprising a population of quantum dots (QDs) embedded in a host matrix and a primary light source which causes the QDs to emit secondary light and a method of making such a device. The size distribution of the QDs is chosen to allow light of a particular color to be emitted therefrom. The light emitted from the device may be of either a pure (monochromatic) color, or a mixed (polychromatic) color, and may consist solely of light emitted from the QDs themselves, or of a mixture of light emitted from the QDs and light emitted from the primary source. The QDs desirably are composed of an undoped semiconductor such as CdSe, and may optionally be overcoated to increase photoluminescence.

1 . (canceled) 
     
     
         2 . A light emitting device comprising:
 a primary light source; and   a glass tube in optical communication with the primary light source and comprising a solid matrix including a plurality of quantum dots dispersed therein which quantum dots are adapted to convert light from the light source to a single color, a mixed color or white light.   
     
     
         3 . The light emitting device of  claim 2 , wherein the glass tube is physically separated from the primary light source. 
     
     
         4 . The light emitting device of  claim 2 , wherein the solid matrix comprises an epoxy. 
     
     
         5 . The light emitting device of  claim 2 , wherein the primary light source comprises a blue LED light source and wherein the matrix comprises a first population of quantum dots of a material and size adapted to emit red secondary light and a second population of quantum dots of a material and size adapted to emit green secondary light. 
     
     
         6 . The light emitting device of  claim 2 , wherein the primary light source comprises a UV or laser light source and wherein the matrix comprises a first population of quantum dots of a material and size adapted to emit red secondary light, a second population of quantum dots of a material and size adapted to emit green secondary light, and a third population of quantum dots of a material and size adapted to emit blue secondary light. 
     
     
         7 . The light emitting device of  claim 2 , wherein the matrix comprises a first population of quantum dots of a material and size adapted to emit red secondary light. 
     
     
         8 . The light emitting device of  claim 5 , wherein the quantum dots in the first and second population each comprise a core comprising a material independently selected from the group comprising CdS, CdSe, CdTe, InP, alloys thereof, and mixtures thereof. 
     
     
         9 . The light emitting device of  claim 8 , wherein the quantum dots in the first and second population each comprise one or more shell layers comprising a material independently selected from the group comprising ZnS, ZnSe, ZnTe, alloys thereof, and mixtures thereof. 
     
     
         10 . The light emitting device of  claim 5 , wherein the quantum dots in the first and second population have a size distribution having less than 10% rms deviation in diameter of the core. 
     
     
         11 . The light emitting device of  claim 6 , wherein the quantum dots in the first, second and third population have a size distribution having less than 10% rms deviation in diameter of the core. 
     
     
         12 . The light emitting device of  claim 3 , comprising a medium between the primary light source and the glass tube. 
     
     
         13 . The light emitting device of  claim 12 , wherein the medium comprises air. 
     
     
         14 . The light emitting device of  claim 12 , wherein the medium comprises a liquid. 
     
     
         15 . The light emitting device of  claim 12 , wherein the medium comprises a polymer. 
     
     
         16 . The light emitting device of  claim 4 , wherein the quantum dots are reacted with epoxide monomers to form an epoxy mixture. 
     
     
         17 . The light emitting device of  claim 2 , where the matrix comprises a material selected from the group comprising polyacrylate, polystyrene, polyimide, polyacrylaraide, polyethylene, polyvinyl, poly-diacetylene, polyphenylene-vinylene, polypeptide, polysaccharide, polysulfone, polypyrrole, polyimidazole, polythiophene, polyether, epoxies, silica glass, silica gel, siloxane, polyphosphate, hydrogel, agarose, and cellulose.