Patent ID: 8093566

Claim:
An upconversion fluorescent nano-structured material comprising at least one compound of formula (M 1 ) j (M 2 ) k X n :(M 3 ) q and at least one polymer, the polymer having a concentration of 5-25 weight %, wherein each X is the same or different and is selected from the group consisting of: halogen, O, S, Se, Te, N, P and As; each M 1 , if present, is the same or different and is selected from the group consisting of: Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, O and NH 4 ; each M 2 is the same or different and is a metal ion; each M 3 , independently, is the same or different and is selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; j is 0≦j≦10; k is 1≦k≦10; n in 1≦n≦10; and q is 0≦q≦10, and wherein the polymer is on the nano-structured material.