Luminescent materials that emit light in the visible range or the near infrared range and methods of forming thereof

Abstract

Luminescent materials and methods of forming such materials arc described herein. In one embodiment, a luminescent material has the formula: [A a Sn b X x X′ x′ X″ x″ ][dopant], wherein A is included in the luminescent material as a monovalent cation; X, X′, and X″ are selected from fluorine, chlorine, bromine, and iodine; a is in the range of 1 to 5; b is in the range of 1 to 3; a sum of x, x′, and x″ is a +2 b; and at least X′ is iodine, such that x′(a+2b)≧1/5.

1 . A luminescent material having the formula:
   [A a Sn b X x X′ x′ X″ x″ ][dopant],
   wherein   A is included in the luminescent material as a monovalent cation;   X, X′, and X″ are selected from fluorine, chlorine, bromine, and iodine;   a is in the range of 1 to 5;   b is in the range of 1 to 3;   a sum of x, x′, and x″ is a+ 2   b;  and   at least X′ is iodine, such that x′/(a+2b)≧⅕.   
     
     
         2 . The luminescent material of  claim 1 , wherein A is selected from potassium, rubidium, and cesium. 
     
     
         3 . The luminescent material of  claim 1 , wherein A is cesium, and a is 1 or 2. 
     
     
         4 . The luminescent material of  claim 1 , wherein b is 1 or 2. 
     
     
         5 . The luminescent material of  claim 1 , wherein at least one of X and X″ is fluorine. 
     
     
         6 . The luminescent material of  claim 1 , wherein at least one of X and X″ is chlorine. 
     
     
         7 . The luminescent material of  claim 1 , wherein at least one of X and X″ is bromine. 
     
     
         8 . The luminescent material of  claim 1 , wherein x′/(a+2b)≧½. 
     
     
         9 . The luminescent material of  claim 1 , wherein x′/(a+2b)≧⅔. 
     
     
         10 . The luminescent material of  claim 1 , wherein a is 1, and b is 1. 
     
     
         11 . The luminescent material of  claim 1 , wherein a is 1, and b is 2. 
     
     
         12 . The luminescent material of  claim 1 , wherein a is 2, and b is 1. 
     
     
         13 . The luminescent material of  claim 1 , wherein the dopant is included in the luminescent material in an amount less than 5 percent in terms of elemental composition. 
     
     
         14 . The luminescent material of  claim 1 , wherein the dopant is included in the luminescent material in an amount in the range of 0.1 percent to 1 percent in terms of elemental composition. 
     
     
         15 . The luminescent material of  claim 1 , wherein the dopant includes anions including oxygen. 
     
     
         16 . The luminescent material of  claim 14 , wherein the anions include at least one of O −2  and OH −1 . 
     
     
         17 . A method of forming a luminescent material, comprising:
 providing a source of A and X, wherein A is selected from at least one of elements of Group IA, and X is selected from at least one of elements of Group VIIB;   providing a source of B, wherein B is selected from at least one of elements of Group IVB;   subjecting the source of A and X and the source of B to vacuum deposition to form a set of films adjacent to a substrate; and   heating the set of films to a temperature T heat  to form a luminescent material adjacent to the substrate, wherein the luminescent material includes A, B, and X, one of the source of A and X and the source of B has a lower melting point T m1 , another of the source of A and X and the source of B has a higher melting point T m2 , and T m1 <T heat <T m2 .   
     
     
         18 . The method of  claim 17 , wherein T m1 <T heat <(T m1 +3T m2 )/4. 
     
     
         19 . The method of  claim 17 , wherein T m1 <T heat <(T m1 +T m2 )/2. 
     
     
         20 . The method of  claim 17 , wherein the source of A and X includes a compound having the formula AX, and the source of B includes a compound having the formula BY 2 , where Y is selected from at least one of elements of Group VIIB. 
     
     
         21 . The method of  claim 17 , wherein subjecting the source of A and X and the source of B to vacuum deposition includes:
 subjecting the source of A and X to at least one of electron-beam deposition and thermal evaporation; and   subjecting the source of B to thermal evaporation.   
     
     
         22 . The method of  claim 17 , wherein subjecting the source of A and X and the source of B to vacuum deposition includes:
 mixing the source of A and X and the source of B to form a mixture; and   subjecting the mixture to vacuum deposition to form the set of films adjacent to the substrate.